Fever and microbiology Flashcards

Question

What is Brill-Zinnzer disease?

Answer 1

* delayed relapse of epidemic typhus, caused by Rickettsia prowazekii * after a patient contracts epidemic typhus from the fecal matter of an infected louse (Pediculus humanus), rickettsia can remain latent and reactivate months or years later * symptoms similar to or even identical to the original attack of typhus, including a maculopapular rash. * this reactivation event can be transmitted to other individuals through fecal matter of the louse vector, and form the focus for a new epidemic of typhus.

Answer 2

* syphillis * non-venereal trepanomates (yaws) * leptospirosis * Lyme * rat bite fever * relapsing fevers

Answer 3

* Leptospirosis * rodents and other small animals most important animal reservoirs, infected in infancy and remain chronically infected, excreting spirochetes in urine * larger mammals may become sick or chronically infected * orgs live in soil or water for weeks * incidence increases after flooding * _Risk factors_ * Occupational (30-50%); farmers, abattoirs workers, vets, sewer workers, rice field workers, military personnel * Recreational; fresh water swimming, fishing, canoeing, * Household exposure; pet dogs, domesticated livestock, rodent infestation

Answer 4

* infection acquired by leptospira penetrating skin via minor cuts or mucous membranes. ?intact skin controversial * Leptospiraemia affects any organ, **usually liver and kidney** * ****Kidneys: Migrates to interstitium, tubules-tubulo-interstitial nephritis * Liver: Centrilobular necrosis. Proliferation in Kupffer cells. Jaundice (icterus) and hepatocellular dysfunction * Skeletal muscle: necrosis * With severe disease disseminated vasculitis * Eye: Recurrent uveitis * Multiplies in blood and tissue.

Answer 5

* leptospirosis * variable, many asymptomatic seroconvertors to mild non-specific febrile illness * incubation period 10 days (2-26) * sudden onset fever, rigors, myalgia, headache, nausea, vomiting, diarrhea, cough * o/e conjunctival suffusion, muscle tenderness, rarely lymphadenopathy, chest signs and rash * ?meningeal signs * biphasic? as immune response appears pt may deteriorate and develop: * aseptic meningitis or * Weil's disease: jaundice, thrombocytopenia, renal failure * Pulmonary syndrome, pulmonary hemorrhage (xray below) * myocarditis leading to cardiac fever

Answer 6

* slender, spiral anaerobic rods * dx usually by serology * IgM RDT available * Elisa IgM * Microscopic Agglutination Test (MAT) * x-reactivity with spirochetes and legionella * though can be seen microscopically in blood or urine, rarely used * blood or urine cultures * PCR

Answer 7

* **Mild leptospirosis:** doxycycline, amoxicillin * in endemic area, **if unable to differentiate from rickettsial illness, doxycycline makes sense** * **Severe leptospirosis:** parenteral penicillin/cephalosporins or erythromycin * **short term prophylaxis for high risk circumstances:** doxycycline weekly * **Jarisch-Herxheimer reaction:**?steroids, evidence inconclusive, concern about increased infections

Answer 8

* leptospirosis * it is found everywhere except the polar regions

Answer 9

* Borrelia spp., at least 4 cause Lyme Disease * B. burgdorferi (North America, Europe, Asia) * B. lonestari (recently described in US) * B. afzelli, B. garinii, B. valaisaiani (Europe, Asia) * microaerophilic, fastidious organism, hard to stain and culture * Ixodes tick (below, note scutum) * In Africa or Asia might be Borrellia spp. where it is reported to be the most common bacterial infection. Transmitted by soft tick (Ornithodoros). Nb cases in Western US, BC and Mexico also.

Answer 10

* *Ixodes scapularis* * ***Lyme disease*** * *Babesiosis* * *Ehrlichiosis* * *See life cycle below. Key points are that* * *nymphs bite humans and transmit Borellia spp. responsible for Lyme disease* * *Adults bite large animals* * *Borellia is transmitted transstadially and transovally*

Answer 11

* Borrellia sp. possibly *Borrellia recurrentis or B. africae* * *or* A family of diseases caused by different species of *Borrelia.* * 2 Kinds generally: * Epidemic Relapsing Fever, or Louse-Borne Relapsing Fever caused by *Borrellia recurrentis* and transmitted mainly by *Pediculosis humanis var corporis* * Endemic or Tick-Borne Relapsing Fever caused by other species of *Borrellia* and transmitted by Soft Ticks. * large spirochetes measuring 10-30 x 0.2-0.5 µm visible in Giemsa * Borrelia genome consists of combination of linear and circular plasmids *

Answer 12

* an agglutination test based on antigenic cross-reactivity between Rickettsia sp and serotypes of Proteus. * non-specific * poor sensitivity and specificity * supplanted by IFA, other serologic methods and PCR for dx of epidemic or louse-borne typhua * not to be confused ith Widal test, which is used for *salmonella* infections

Answer 13

* epidemic or **louse borne typhus** is transmitted when *Rickettsia prowazecki* - infected species of human body lice (*Pediculosis humanus)* shits on human and this is rubbed in through wound or conjunctivae. (Not transmitted by **bite** of louse.)

Answer 14

* recurrent louse-borne typhus occurring from latent infection with *Rickettsia prowazeki* becoming re-activated * may occur months or years after original infection

Answer 15

* because once *Rickettsiae* multiply sufficiently in the louse they rupture the louse intestine, and the louse dies in 8-12 days * the infection incubates for about 12 days before becoming symptomatic

Answer 16

* also known as louse-borne typhus * incubation period about 12 days * presents with high fever, myalgia, **headache** & prostration. Conjunctiva suffused, delirium * rash about day 4, central, and macular, lesions may later become petechial or purpuric * Complications: pneumonia +/- meningoencephalitis, myocarditis * untreated, high mortality

Answer 17

* doxycycline 200 mg stat dose in epidemic situations of Epidemic or Louse-Borne Typhus * in Meditteranean Spotted Fever (*Rickettsia conorii)* 200 mg x 2 effective * **Otherwise** * doxycycline at least 5 days for severe cases an in RMSF (Rocky Mountain Spotted Fever) * chloramphenicol 500 mg q 6 hrs x 7 days an alternative * Rifampicin in areas where TetR (eg. northern Thailand) * prospective trials needed for fluroquinolones, azithromycin etc.

Answer 18

* Med vs African Spotted Fevers * org: *R. conorii* vs *R. africae* * affects tourists: rare vs common * fever: in both * rash: common vs less common * eschar: single vis multiple * regional nodes: yes to both but more common in ASF * Mortality 2% vs rare

Answer 19

* murine typhus is similar in presentation but less severe than epidemic typhus, which itself is usually less severe than tick borne typhus which is less severe than scrub typhus * i.e. in terms of severity: scrub typhus\>tick-borne typhus\>epidemic typhus\>murine typhus * caused by *R. typhi* rather than *R. prowazecki* and transmitted by fleas (Xenopsylla cheopis, the Oriental rat flea) rather than lice (Pediculosis humanus) * typically no eschar in murine typhus

Answer 20

* species of hard ticks: Amblyomma, dermacentor * unlike Ixodes, these remain a short time on the host, so less likely to be detected * fever and eschar in \>90% of cases, followed by rash, headache, regional lymphadenitis and arthralgia ( in that order) * *R. africae* has displaced *R. conorii* * *dogs, rondents, wild animals eg. hippo are main vectors*

Answer 21

* less severe syndrome * also easier on the vector, which is the oriental rat flee. *R. typhi* does not kill the flea, so they can pass the disease onto rats and other reservoir mammals (e.g opossums, racoons and skunks). This helps to maintain a large reservoir of rats, which can in turn infect more fleas * bit of rat can rarely transmit *R. typhi*

Answer 22

* *Borrelia recurrentis causes LBRF* * the vector is *Pediculosis humanus* * many species of Borrelia cause TBRF * Untreated LBRF ~70% * Untreated TBRF ~10%

Answer 23

* *Ornithodoros moubata* * Tick Borne Relapsing Fever * Bite is painful, relatively brief, occurs at night * transmitted through feces smeared into skin, conjunctiva * Various species of *Borellia* esp *B. duttoni* and *B. crocidurae* in Africa

Answer 24

* tends to occur in epidemics in situations of overcrowding * although called "epidemic" it is also endemic in **highland** regions of Ethiopia and Burundi as well as other **highland** areas of Africa, India and the Andes. * Humans are the reservoir host. * Vector is pediculosis capitis * organism is *Borrelia recurrentis* * *louse provokes itching and is crushed with scratching, releasing* Borrellia via abrasions and mucous membranes

Answer 25

* *Borrelia* multiply by simple fission, taken up by Reticuloendothelial system, esp Liver and spleen * Intrahepatic cholestasis * Neurotropic (TBRF \>\>\> LBRF) * Bleeding dyscrasias (hemorrhage/micro-thrombosis (LBRF \> TBRF) * Thrombocytopaenia * myocardial and pulmonary injury common * relapses result from antigenic variation

Answer 26

* incubation usually 4-8 days (range 2-15) * typically sudden onset high fever, headache, confusion, meningism, myalgia, arthralgia, nause, vomiting, sometimes dysphagia * dyspnea, cough may be severe, sputum may contain Borrelia * Hepatomegaly * jaundice 50% with LBRF, \<10% TBRF * splenomegaly, increased risk of rupture * petechiae, rashes, epistaxis, conjunctival injection, hemorrhages more common in LBRF * complications: pneumonia, nephritis, parotitis, arthritis, cranial and per neuropathies, meningoencephalitis, meningitis, acute ophthalmitis, iritis * myocarditis ⇒ sudden, fatal arrhythmias * most complications more common and more severe in LBRF with case fatality rate \> 70% in epidemics * mortality rate \<10 % in TBRF

Answer 27

* incubation period 4-8 days (range 2-15) * Abrupt onset (“crisis phase”) * High fever * Headache * Delirium * Cough * Jaundice esp in LBRF * Hepatosplenomegaly * Conjunctival suffusion and rash (macular or petechial) - these & bleeding more common in LBRF * dyspnea, cough, sputum may be +ve *Borrelia* * *Untreated LBRF case fatality 70%, TBRF only 10%* * *Complications include:* * *pneumonia* * *nephritis* * *parotitis* * *arthritis* * *cranial and peripheral neuropathy* * *meningitis & meningoencephalitis* * *opthalmitis, iritis* * *myocarditis*

Answer 28

* malaria * typhus * typhoid * meningococcal septicemia/meningitis * dengue * hepatitis * leptospirosis * yellow fever * other VHF

Answer 29

* microsopy: Borrelia large spirochetes measuring 10-30 x 0.2-0.5 µm * visible in Giemsa or Field stain or dark-field or immune fluorescent microscopy * Spirochaete density **10x higher** in B recurrentis vs B duttonii * may be surprise finding in pt with suspected malaria and dual infections may occur in which Borrelia may be overlooked * may be concentrated in Buffy Coat after centrifugation * infected blood or CSF innoculated in mice or rats yields borreliae in blood after 2-3 days * Serology unreliable * PCR increasing role * Lab findings: non-haemolytic anemia; polymorphonuclear leukocytosis; thrombocytopenia; transaminitis; lymphocytic CSF in patients with meningeal sxs * GlpQ serology: useful for differentiating between non-Lyme and Lyme Borrelia species; if patient already on treatment

Answer 30

* doxycycline single dose effective in most LBRF and TBRF * however, usual practice is to give 5-10 day course to minimize relapse * ceftriaxone recommended for meningitis or encephalitis * Jarisch Herxheimer rxn in 80-90% of pts treated for LBRF and 50% of TBRF, esp if treated with bactericidal Abx (pen, ceftriaxone) * managed with fluid support, ?Mestazinol - partial opioid antaganist? one study showed monoclonal FAb directed against TNF reduces severity, but only experimental * Main thing is fluids and don't give up

Answer 31

* De-louse (Don’t scratch, don’t crush) * DDT, Permethrin or Malathion powder to skin and clothing * Heat sterilize clothing ideally but impossible in refugee camps * Improve routine hygiene facilities * Mass pre-exposure prophylaxis not recommended but consider single doses during de-lousing * Tick-borne: cut grass, residual spraying * No vaccine

Answer 32

* Relapsing fever is a common and underdiagnosed cause of fever in many areas of Africa * Diagnosis may be difficult especially in tickborne * Louse-borne may carry a high mortality in outbreaks * The Jarisch-Herxheimer reaction can be difficult to manage

Answer 33

* Dengue * Hantavirus * Viral hepatitis * Malaria * Meningitis * EBV and CMV * HIV * Rickettsial disease * Typhoid fever

Answer 34

* the most widespread zoonosis, found everywhere except polar regions * 2 main pathogenic species *L. interrogans and L. bireflexa* although 250 serovars potentially pathogenic * motile spirochetes infect rats and mice, and other mammals. rats relatively assymptomatic carriers, other mammals, inc dogs become sick * survive weeks in water and in soil * most commonly enter body via breaks in skin or mucous membranes, occ via inhalation, bite of infected animal, sexual contact

Answer 35

* morphologically and serologically identical to *Treponema pallidum* subsp. *pallidum* * only minor antigenic differences * **all show +ve syphilis serology** * differ only in clinical presentation * transmission usually through direct contact * can be latent infection for many years

Answer 36

* post WWWII large tropical areas Yaws endemic * massive treatment programme with Benzathine Penicillin from 1952-1964 reduced incidence from 150 million to 2.5 million - 95% reduction * since then widespread elimination programme stopped, resurgence of Yaws since 90's leading to new global strategy launched in 2012 aimed at trying to eliminate Yaws by 2020 * India now free of Yaws

Answer 37

* *Treponema pallidum* subsp. *pertenue* * contagious non-venereal infection * primarily affecting children \<15 yrs (peak 6-10), M=F * Warm tropical humid rural areas (Africa, Asia, South America, Oceania) * associated with overcrowding and poor sanitation

Answer 38

* Primary * incubation 3 wks (9-90 days) * Mother Yaw initial lesion at inocularion site * often at site of prior skin injury or insect bite * Secondary * Widespread dissemination of treponemes * multiple skin lesions last for \>6 months * "Crab Yaws" diff. walking due to lesions on palms & soles, hyperkeratoses * Latent * Usually assymptomatic * skin lesions can relapse for up to 5 yrs * most remain non-infectious and in latent phase for lifetime * Tertiary * after 5-10 yrs 10% untreated progress to tertialy with bone, joint, soft tissue deformities

Answer 39

* Mother Yaw and Daughter Yaws * seen Primary Stage of Yaws * incubation period 3 wk (9-90 days) * Initial lesion at inoculation site often appears at site of prior skin injury or inoculations site * during incubation ⇒ subq lympatic and hematogenous spread to produce daughter Yaws * lesion enlarges to papilloma then resolves after 3-6 months

Answer 40

* Secondary Stage of Yaws * widespread lymphatic and hematological dissemination of treponemes * multiple skin lesions, near primary site or elsewhere * lesions last \> 6 months * macules, papules, nodules and hyperkeratotic lesions. * may develop 'Crab Yaws' - referring to diff walking due to lesions on palms, soles, hyperkeratoses * lesions can ulcerate or heal spontaneously

Answer 41

* usually assymptomatic * skin lesions can relapsue for up to 5 yrs * most remain non-infectious * **most remain in latent phase for lifetime**

Answer 42

* Tertiary yaws with gummatous periostitis leading to monodactylitis on left, sabre tibia on right * other bone, joint, soft tissue deformities occur * rare to see cardio-neural involvement * chronic periostitis of tibia lead to sabre shins * monodactylitis, juxta-articular nodules * rhinopharyngitis mutilans (nasal cartilage destroyed)

Answer 43

* impetigo * leishmaniasis * leprosy * molluscum contagiosum * sickle cell anemia * **tuberculosis** * tungiasis * scabies * tropical ulcer * plantar warts * psoriasis * **venereal syphilis** * Bejel * osteomyelitis

Answer 44

* Primary lesion of Bejel or Endemic syphilis * caused by *T. pallidum* subsp *endemicum* * worldwide distribution, now only dry, arid regions Central, Southern Africa, Middle East, Turkey * Increasing in Sahara, Mali, Burkina Faso * Freq unknown, seropositivity 22% in Burkina Faso, 12% Niger

Answer 45

* mucous patches of Bejel or endemic syphilis * these are the most common initial lesions * spread by direct contact via skin or mucous membranes * 75% of cases children 2-15 yrs * adults affected when in close proximity to kids * F\>M * mothers more affected via breast feeding * Whole families can be affected

Answer 46

* angular stomatitis of Bejel, a primary lesion * Primary, Secondary, Latent, Tertiary * Incubation period 9-90 days * skin lesions resemble chancres of venereal syphilis, small/white ulcers, usually painless * oral lesions easily missed * primary lesions heal in 1-6 wks (often undiagnosed)

Answer 47

* macerated, eroded patches on lips, tongue, tonsils * condyloma lata can appear in anogenital area * non-tender generalized lymphadenopathy common * painful osteoperiostitis of long bones occurs * angular stomatitis

Answer 48

* destructive gummas of skin, bone, cartilage in tertiary Bejel leading to "Saddle nose" * palate perforation also possible * skin depigmentation after healing * ocular manifestations may include uveitis, optic atrophy, chorioretinitis * (neuro and cardiac involvement uncommon)

Answer 49

* eczema * mycoses * psoriasis * leprosy * herpes * **_Later Stages:_** * **__**malignancy * mycosis fungoides * lupus vulgaris * SLE

Answer 50

* tertiary venereal syphilis * tb * leprosy * mucocutaneous leishmaniasis * Wegener's granulomatosis

Answer 51

* Pinta, caused by *T. pallidum* supsp. *carateum* * pigmentary changes and depigmentation major characteristic * more benign course * tends to affect **Young Adults, peak age 15-30** * **M=F** * geography different: this tends to be Central and South America, Cuba * now relatively rare, only ?a few hundred cases reported per year, much more common in 80's

Answer 52

* Primary * incubation 2-3 wksSave * skin lesions macule/papule/plaque on exposed areas * enlarges and becomes pigmented and hyperkeratotic * Secondary * 3-9 months after infection" disseminated lesions or *pintids.* * Latent * assymptomatic * Tertiary * disfiguring pigmentary lesions: hypochromic/achromic/hyperpigmented/atrophic * lesions appear red, white, blue, violet and brown

Answer 53

* leprosy * syphilis * yaws * discoid lupus * eczema * tinea versicolor * vitiligo

Answer 54

* yaws, bejel, pinta * serodiagnosis for syphilis can be used, all +ve * non-treponemal test * RPR/VDRL * confirmatory treponemal tests: TPHA, FTA, EIA (IgG/IgM) * dark field microsopy of early lesions * epidermal histology shows treponemes

Answer 55

* Benzathine penicillin drug of choice * Adults: 2.4 MU IM one doses * Ped: 50,000 U/kg once, not to exceed 2.4 MU * Usually non-infectious after 24-48 hrs * If unavailable Pen V x 7-10 days or * tetracycline or erythromycin x 15 days * Azithomycin non-inferior (Lancet 2012) * Probable effectiveness of single lower dose as used for trachoma

Answer 56

* inhalation via aerosols * ingestion of dairy products * inoculation/hypersentivity * human breast milk * sexual transmission * blood transfusiom

Answer 57

* Gm -ve coccobacillus, Brucella * causes Undulant Fever * It is a zoonosis, occasionally infecting man * B. melitensus infects goats & cattle: **aggressive, acute infection in man** * B. abortus infects cattle causes **chronic infection in man** * B. suis, pigs, causes **abscesses in mans**

Answer 58

* If there is a history of exposure to fresh water (including swimming pools) in the past month then the presence of fever, myalgia, and redness and oedema of the conjunctiva (especially of the palpebral conjunctiva) makes the diagnosis very probable. Routine blood tests are non-specific. The WBC may be normal, decreased or increased. Platelets are usually decreased but not alarmingly so. Liver function and/or kidney function may be altered, but again the results are non-specific. Urine contains leptospires during the first week but results of culture take some weeks to read and are of low sensitivity. Urinary antigen tests and rapid dipstick tests are attractive but do not cover all the possible strains. The MAT test is difficult to perform and usually requires paired sera 1–2 weeks apart so that the diagnosis is only made during convalescence or when the disease is progressing unfavourably. The MAT test involves antigens representing 20 serogroups of leptospirosis and will detect agglutination with serum or urine antibody providing the matching serovar is present. It is positive in many cases from the 5th day onwards. Polymerase chain reaction (PCR), including real-time PCR assays, are excellent but are not available everywhere. Doxycycline is a cheap and reliable treatment when given in time. Doxycycline can also be used as a chemoprophylaxis in a dose of 200 mg once a week. Frequently, in an endemic area, the clinician is unable to differentiate quickly between leptospirosis and a rickettsial infection and vice versa. In such a situation oral doxycycline 100 mg daily is a sensible option.

Answer 59

* majority asymptomatic seroconversion * incubation period about 10 days * general: sudden onset fever rigors, headache, n, v, diarrhea; conjunctival suffusion & muscle tenderness * more rarely hepatosplenomegaly, lymphadenopathy, chest signs & rash * as immune response appears may develop one of 4 specific sx 1. aseptic meningitis - up to 50-80% 2. Weil's disease: jaundice, thrombocytopenia, renal failure, liver fx usually rel well preserved 3. pulmonary syndrome: severe pul hemorrhage and rds 4. cardiac syndrome: myocarditis * diff dx: malaria, typhoid, influenza, rickettsial infection (esp scrub typhus), arbovirus inf (inc dengue)

Answer 60

* Undulant fever or Brucellosis * undulating pattern with a periodicity of 10-14 days. 1. asymptomatic 2. acute\<1 month 3. subacute/relapsing 1-6 months 4. chronic \> 6 months 5. hypersensitivity * prefer the term "active brucellosis with or without localisation" * also consider focal symptoms, which may be easily missed because of chronicity, non-specificity: * Fever * GI disturbance * MSK: myalgia, arthralgia, backache, lethargy * headache * respiratory * GU - orchitis * psychiatric - primarily depression, not psychosis * hepato/splenomegaly in a minority

Answer 61

* Brucella melitensis - goats & camels - aggressive, acute disease * B. abortus - cattle - chronic * B. suis - pigs - abscesses * B. canis - dogs - rare in man * (recently B. pinnipedialis (seals) and B. cetis (whales))

Answer 62

* note: very easy to miss without high index of suspicion because of chronicity 1. Non-specific * fever, lethargy, sweats, anorexia * difficutly walking * pain "all over" or localized 2. Monoarthritis esp in children 3. Spinal disease: * men * \>50 * chronic

Answer 63

* Brucellosis, is the commonest zoonosis, about 500,000 cases annually. * Leptospirosis is the most widespread zoonosis, occurring everywhere except polar regions. * Ascariasis is the most common helminthic infection in the world with over 1 billion people infected.

Answer 64

* based on a systematic review 2008 BMJ * Should be treated with 2 drugs one from: * doxycycline * cotrimoxazole * rifampicin * with either * streptomycin or * gentamycin for the first 2 weeks * uncomplicated acute disease should be treated for a total of 6 weeks * Chronic or complicated (endocarditis, neurologic disease or bone disease) should be treated for total of 3 months

Answer 65

* In endemic area, **think Brucella.** * **take history!** * In ALL spinal TB consider Brucella and vice versa. * Full micro work-up before treatment - consult with lab * Over-treat to prevent relapse, use 2 drugs (one of which aminoglycoside) - in brackets my addition * Prolonged f/u * Coordinated human and veterinary public health approach

Answer 66

* can't control human disease without controlling animal disease * Brucellosis is one of several diseases where combined approach advocated (also HAT) * Human disease is controlled by animal disease control (animal hygeine + vaccine) plus pasteurization * Control by animal vaccination only cost-effective if both animal and human cost savings are included * So Need * Animal control * test and slaughter (compensate farmers) * hygeine * vaccination * People * vaccination (in development) * health education * lab safety * effective animal control

Answer 67

* Culture if possible, from blood, bone marrow or other tissue or fluid. * But not sensitive * Lab needs alerting as brucella culture aerosolizes, safety issue for lab * Serology - Tube Agglutination Titre or ELISA * Prozone effect: high Ab titres lead to cross-linking of Ab's and blocking of agglutination with Ag. Need to dilute for agglutination to occur.

Answer 68

* an organism that supports the immature or non-reproductive forms of a parasite. * eg malaria, trypanosomiasis

Answer 69

* typhoid * blood culture

Answer 70

* Ceftazidime or carbopenem * This is a clinical description of melioidosis, in an individual with relevant risk factors (diabetic Thai rice famer). Ceftazidime (or carbopenems) would give adequate cover for B. pseudomallei, whereas the other options, including ceftriaxone, would not.

Answer 71

* This antibiogram is so unusual for Pseudomonas that it has been used successfully as a screen for B. pseudomallei. * Ceftazidime or meropenem x at least 10 days * follow by cotrimoxazole orally x 12-20 wks to prevent relapse (otherwise relaps rate is 5-25%)

Answer 72

Melioidosis is caused by gram-negative bipolar, safety pin-shaped bacillus, B. pseudomallei. Familiarity with different presentations of this infection is essential for early diagnosis as delayed diagnosis contributes to increased mortality and morbidity. Melioidosis is associated with a range of mortality from 10% [3] to 39% [4]. For those with septic shock, it can rise up to 86% [5]. Globally, it is seen in tropical climates, especially in Southeast Asia (Malaysia, Thailand and Singapore), China, Taiwan and northern Australia [6, 7]. It has been reported anecdotally from all developing countries, although it frequently goes unrecognized. From India, cases are reported frequently from all regions, suggesting that it is becoming an endemic disease, but a large number of cases are not diagnosed [8]. This perceived low prevalence is due to the lack of awareness among physicians, microbiologists and poor laboratory facilities. It is usual for laboratories in non-endemic locations to misidentify the bacterium as commensal. Although there has been expansion of the disease in tropical countries due to global warming and population movement, many cases are unmasked by improved clinical surveillance and better diagnostic methodology [9]. Melioidosis is transmitted by inhalation of contaminated dust or water droplets, percutaneous inoculation and ingestion of contaminated water. Our patient most probably acquired the infection by ingesting contaminated water. It is a seasonal disease more common in wet season and epidemics occur during tropical monsoonal storms, cyclones, hurricanes and typhoons [10]. There may be a shift from inoculation to inhalation as the predominant route of spread during epidemics [11]. It is a disease of adults with \<5% cases belonging to paediatric age group [12]. Risk factors for melioidosis are diabetes mellitus, chronic renal failure, alcohol abuse, thalassaemia, chronic lung or liver disease, malignancy and immunosuppression. Diabetes mellitus is found in up to 60.9% of affected patients [1]. Latent infection is common, with one study reporting a 4% reactivation rate into active illness [13]. This can occur many years after exposure—at one point in time, this was referred to as the Vietnamese time bomb due to its reactivation in returned serviceman from Vietnam [14]. Melioidosis is divided into subclinical, acute and chronic disease. Acute cases are those where symptoms were present for \<2 months. The spectrum of clinical presentations ranges from to asymptomatic or minor localized abscess or nodule to severe, fulminant disease (such as shock, multiorgan abscesses and death). Exposure to bacilli most commonly results in subclinical disease. Clinical disease presents most commonly in acute form and only 9% presents as chronic illness [12]. The most common presentation of melioidosis is pneumonia, occurring in more than half the cases [15]. Acute melioidosis commonly presents as pneumonia and may progress to septic shock with mortality in up to 90% of cases [13]. Infiltrates can occur in lungs which coalesce and cavitate and may cause multiple metastatic abscesses. Initially, our patient had chest infiltrates that were non-specific. Chronic disease closely mimics tuberculosis or malignancy [6]. However, melioidosis can present in a wide variety of patterns, ranging from genitourinary symptoms to encephalomyelitis [13]. Treatment has two phases: the intravenous intensive phase for acute disease, followed by eradication phase [16]. Intravenous ceftazidime (2 g, 6 hourly) and meropenem (1 g, 8 hourly) are agents of choice in the intensive phase. Cotrimoxazole is used in the maintenance phase. Treatment duration depends on local versus severe systemic infection. In local or mild disease, intensive phase is of 2–4 weeks followed by 3 months of maintenance therapy. In severe infection including neurological disease, initial intensive therapy is prolonged for 6–8 weeks. It is followed by an eradication phase with oral cotrimoxazole for the next 6 months [17]. Meropenem in double dose is preferred in neurological melioidosis [13].

Answer 73

* **Risk factors** * Travel history is key. Longest reported incubation period is 62 years. * **Major (by proportion)** * Exposure to soil and surface water in endemic area * Diabetes mellitus (risk x12) * **Minor** * Thalassaemia major * Immune suppression (corticosteroid use) Cancer * Renal failure and kidney stones

Answer 74

* anthrax bacillus * large * encapsulated Gm +ve * non-motile * spore forming bacillus (picture of spores attached below) * note growth in chains * tacky, granular, bee's eye growth in colonies * non-hemolytic

Answer 75

* anthrax spores * spores inoculated into portal of entry * skin, gut, lungs * ingested by macrophages * migrate to regional lymph nodes * spores germinate to vegetative bacilli * bacillary capsule coded by virulence plasmid pX02 resists phagocytosis * bacilli release toxin coded by pX01 with 3 components * Protective antigen (PA) binds cell receptor ⇒ entry * Edema factor (EF) + PA produce edema toxin * Lethal factor (LF) + PA produce lethal toxin * Toxins lead to cell death * Clinically produces widespread edema and necrosis

Answer 76

1. cutaneous (95%) * wool sorters disease 2. GI (rare, ?underreported) 3. Inhalational 4. (meningeal)

Answer 77

* cutaneous anthrax (hide handler's disease) * 95% of naturally occurring cases * subQ inoculation of spores * hands, forearm, head, neck, back * incubation \< 1 to 7 days * Small **painless** papule ulcer with marginal vesicles (24-28 hrs) * Eschar with local **edema** (2-6 d) * Untreated mortality 5-20% * **Edema, no pain, no pus, exposure (occ) history**

Answer 78

* Cellulitis (Strep/Staph) * Tick Typhus * Leishmania * Pseudomonas * Herpes viral skin infection * Ulceroglandular tularemia * Spider bite * Plague * zoonotic pox (orf from sheep or cowpox)

Answer 79

* rare (\<5% reported cases) * prob underdx * 1 case US 2001 * Oropharyngeal * adenopathy, edema, ulceration etc * Intestinal * fever,syncope, malais * abd pain, n, v * ascites, acute abd, shock * High mortality * may need surgery

Answer 80

* Wool sorter's disease * some knowledge from Sverdlosk accident * much from US terror attacks * incubation 1-5 days * hemorrhagic adenopathy, mediastinitis * pleural effusions * bacteremia * meningitis common accompaniment

Answer 81

* cipro 400 mg iv bid * cipro 500 mg po bid * (doxy 100 mg bid/ benz pen) * PEP prophylaxis for 30-60 days * because sporulated forms may remain in lungs for 2 months * cipro 500 mg bid (+/- vaccination) * doxy 100 mg bid * Vaccine used by US/UK troops

Answer 82

80% in US 45% in UK 50% worldwide

Answer 83

* Four recommendations 1. Reduce use of medically important antimicrobials 2. Stop use of antimicrobials for growth promotion 3. Stop use of antimicrobials when no clinical illness present 4. Control and restrict the use of antimicrobials in animals that are considered critically important to human health

Answer 84

* *Commonest* * *H. influenza - small, non motile* Gm neg coccobacillus (may look Gm pos unless gm stain carefully performed) * *N. meningitidis -* Gm neg diploccocus * ind clusters or epidemics * *S. pneumoniae -* Gm pos lanceolate diplococcus, may occur singly or short chains * *Neonates* * *Grp. B Strep -* Gm pos coccus * *E. coli -* Gm neg rods * individual cases or clusters * *L. monocytogenes - small* Gm pos rods

Answer 85

* Gm neg diplococcus * 10-20% carriage rate, higher in epidemic situations * 13 meningococcal serogroups * infections mainly by A, B, C, W, X, Y * A causes 80% of outbreaks * B causes endemic meningitis in Africa

Answer 86

* *H. influenza* * small, motile, Gm neg coccobacillus * may look gm pos on poorly done stain * 6 serotypes * B causes most disease * Pharyngeal carriage important, vaccine success may be due to reduced carriage rate * Most disease under 5; rare above this * in young children fatality rate gen higher than N. meningitidis

Answer 87

* all kids under 5 * 2, 4, 6 months, booster at 12-15 mo * also at risk inc. splenectomized, sickle cell, leukemia, HIV

Answer 88

* E. coli * Gm neg bacillus * grows well on common media * lactose fermenting and beta hemolytic on blood agar

Answer 89

* *Strep pneumoniae* * lanceolate, Gm pos diplococcus, sometimes growing singly or in short chains * Alpha hemolytic * normal inhabitant of resp tract * causes pneumonia, sinusitis, otitis medi, meningitis; also osteomyelitis, septic arthritis, endocarditis, peritonitis, cellulitis, brain abscess * meningitis mostly in very young and very old

Answer 90

* *Listeria monocytogenes* * small Gm pos rods, sometimes in short chains, in direct smears may look coccoid and be taken for streptococci * Hemolyic on blood agar not sufficient to dx from other Listeria * sepsis and meningitis/encephalitis in neonates * also preg women and adults with weakened immune systems

Answer 91

* *Pseudomonas aeruginosa* * Gm neg rod shaped bacillus * almost all strains motile by means of single polar flagellum * increasingly important cause of nosocomial infection in pts with compromised host defenses, elderly, hospitalized \> 1 wk, sev burns, HIV * UTI, respiratory, dermatitis, soft tissue infections, bacteremia, bone and joint, GI, meningitis

Answer 92

* *Cryptococcus neoformans* * pleomorphic, uninucleate thin walled yeast 2-20 µm diameter * usually spherical to elliptical surrounded by thick mucinous capsule * single "tear drop" budding frequently seen * Stains: because only pathogenic fungus with capsular material, easily demonstrated with variety of stains inc mucicarmine, PAS or alcian blue. Also stains with Gm stain and easily dx from bacteria

Answer 93

* f.u tests * H. flu wil be oxidase neg * N. meningitidis will be oxidase +ve * Can also do sugar metabolism test: * N. meningitidis uses Glucose and Maltose but not Lactose or Sucrose

Answer 94

* N. meningitidis (and H. flu) are both Oxidase Positive and turn blue with oxidase reagant, so the distinction between them relies on morph differences on gm stain. * also metabolizes glucose and maltose, but not lactose or sucrose.

Answer 95

* Fever \>38.3 ⁰C on 3 occasions * \>3 wk duration * Exclusion of immunocompromised pts: * neutropenia (WBC \< 1 x10⁹/L &/or ANC \< 0.5 x 10⁹/L) during at least 1 wk within 3 months preceding the fever * known HIV * known hypogammaglobulinemia (IgG \< 50% normal) * use of equiv of \>10 mg pred during at least 2 wk in prev 3 months * Diagnosis uncertain after thorough history-taking, physical exam and following obligatory investigations: ESR or CRP, Hgb, Plt count, WBC, diff, lytes, cr, TP, protein electrophoresis, alk phos, serum transaminases, LDH, CK, ANA, RF, U/A, blood cultures x 3, urine culture, cxr, abd us, TST or IGRA, HIV test

Answer 96

* Infections * Bacterial * infective endocarditis * abd abscess * diverticulitis * renal abscess * lung abscess * prostatitis * sinusitis * infected vascular catheter * septic arthritis or osteomyelitis * spondylodiscitis & epidural abscess * infected joint/vascular prosthesis * dental infection * brucellosis * Q fever * rickettsiosis * tuberculosis * enteric fevers * Viral * cmv * coxsackie virus * EBV * Hep A, B, C, or E * HIV * parvovirus * Fungal * endemic mycosis * aspergillosis * candidiasis * cryptococcosis * histoplasmosis * Parasitic * malaria * leishmaniasis * Non-Infectious Inflammatory Disorders * Systemic rheumatic diseases * AS, Behcet's disease, cryoglobulinemia, dermatomyositosis, Felty's syndrome, gout/pseudogout, mixed CT disease, polymyositis, reactive arthritis, RA, SLE, Sjögren's sydnrome * Vasculitis * Eosinophilic granulomatosis with polyangitis (Churg-Strauss syndrome), giant cell vasculitis/PMR, granulomatosis with polyangiitis (Wegener's granulomatosis), polyarteritis nodosa, Takayusu's arteritis * Autoinflammatory disorders * Adult onset Still's disease, Familial Mediterranean Fever * Granulomatous disease * Sarcoid * Neoplasia * Hematological * lymphoma, leukemia, multiple myeloma, myelodysplastic syndrome, myelofibrosis * Solid tumours * breast ca, colon ca, hepatocellular ca, lung ca, pancreatic ca, renal cell ca * Misc. * Adrenal insufficiency, amyloidosis, atrial myxoma, autoimmune hemolytic anemia, autoimmune hepatitis, Castleman's disease, drug fever, factitious fever, Inflammatory Bowel Disease, hemaophagocytic syndrome, pheochromocytoma, pulmonary embolus/thrombosis

Answer 97

* Q fever, also called query fever, is a bacterial infection caused by the bacteria Coxiella burnetii. The bacteria are most commonly found in cattle, sheep, and goats around the world. Humans typically get Q fever when they breathe in dust that was contaminated by infected animals

Answer 98

* Whipple disease is a systemic disease most likely caused by a gram-positive bacterium, Tropheryma whippelii. [1, 2] Although the first descriptions of the disorder described a malabsorption syndrome with small intestine involvement, the disease also affects the joints, central nervous system, and cardiovascular system. * (not for TM course)

Answer 99

* Ehrlichiosis is the general name used to describe several bacterial diseases that affect animals and humans. Human ehrlichiosisis a disease caused by at least three different ehrlichial species in the United States: Ehrlichia chaffeensis, Ehrlichia ewingii, and a third Ehrlichia species provisionally called Ehrlichia muris-like (EML). Ehrlichiae are transmitted to humans by the bite of an infected tick. The lone star tick (Amblyomma americanum) is the primary vector of both Ehrlichia chaffeensis and Ehrlichia ewingii in the **United States**. Typical symptoms include: fever, headache, fatigue, and muscle aches. Usually, these symptoms occur within 1-2 weeks following a tick bite. Ehrlichios is diagnosed based on symptoms, clinical presentation, and later confirmed with specialized laboratory tests. The first line treatment for adults and children of all ages is doxycycline.

Answer 100

* Tularemia is a disease of animals and humans caused by the bacterium **Francisella tularensis**. **Rabbits, hares, and rodents** are especially susceptible and often die in large numbers during outbreaks. Humans can become infected through several routes, including: **Tick and deer fly bites** **Skin contact with infected animals** **Ingestion of contaminated water** **Inhalation of contaminated aerosols or agricultural dusts** **Laboratory exposure** In addition, humans could be exposed as a result of bioterrorism. Symptoms vary depending on the route of infection. Although tularemia can be life-threatening, most infections can be treated successfully with antibiotics. Steps to prevent tularemia include: Use of insect repellent Wearing gloves when handling sick or dead animals Avoiding mowing over dead animals In the United States, naturally occurring infections have been reported from all states except Hawaii.

Answer 101

* Blastomyces dermatitidis, Histoplasma capsulatum, Paracoccidioides brasiliensis, (Coccidioides immitis) is in parentheses because it changes to a spherule of endospores, not yeast, in the heat), Sporothrix schenckii. This phrase says "Probably" because there is always an exception (in this case fungi like Candida albicans) which change in the opposite direction: to mold in the heat!

Answer 102

* 10⁵orgs. Innocula up to 10⁹ wil just shorten the incubation period * average 14 days (1-3+ wks) * onset gradual, rigors unusual * grad rising fever in first week, evening rise * then high for a week and falling by lysis in 3rd or 4th week * present with malaise, gen aches and pains, anorexia, abd pain or discomfort, headache, diarrhea or constipation, non-productive cough * Complications start about day 15. * early looks well, after 2 weeks may look very toxic, mentally stuporose and gravely dehydrated * high fever, apathy, signs of bronchitis and meningism * Truncal Rose spots from day 7 - blanching with spots * relative bradycardia * The organisms penetrate the small intestine and are carried via the lymphatic duct to the general circulation. They lodge in lymph nodes, especially in Peyer’s patches, and in the macrophages of the liver and spleen where they multiply. They then spill out from these sites causing a second bacteraemia. As a result there is a pan-organ systemic infection with a predilection for the gall bladder, bone, brain and spleen. This second bacteraemia coincides with the start of clinical disease. The incubation period is generally in the region of 1–3 weeks depending on the magnitude of the infecting load and the resistance of the patient. Overt disease is common in younger people viz. the 2–10 years of age bracket.

Answer 103

* Perforation * Hemorrhage: rptd small bleeds, poss massive hemorrhage in 3rd week * Severe toxemia: delirium, obtundation, stupor, coma, shock * Hemolytic anemia: typhoid depressed G6PD in normal as well as def pts * Typhoid lobar pneumonia * meningitis * renal disease: failure or acute nephrotic syndrome * Typhoid abscess anywhere: spleen, liver, brain, breast, skeletal * septic arthritis, osteomyelitis, Zenkers muscle degeneration, polymositis * other: parotitis, acute cholecystitis, dvt, psych, Guillain Barré

Answer 104

* blood culture, esp in 1st and 2nd week, need large volume * bone marrow culture * aspirate rose spots * csf * abscess pus * stool but pt may be chronic carrier * Serology * Widal test lacks spec and sens * Treatment: depends on local sensitivity * generally iv ceftriaxone, cefotaxime, cefixime best (IV route preferred at first) * alternatives inc fluroquinolones, amoxil, coterimoxazole (beware nephrotoxicity) * steroids very iffy

Answer 105

* Typhoid: Salmonella enterica serovar Typhi and * serovars Paratyphi A, B, C * Gm neg bacilli of the Enterobacteriacae * All carry O (somatic) and H (flagellar) antigens. This is the basis for the Widal test (see below). However the Vi antigen is peculiar to S. typhi and S. paratyphi C.

Answer 106

* Sickle cell and G6PD more likely to have hemolysis * Chronic fecal carriers may have * chronic cholecystitis with or without gallstones * path abnormalities in urinary tract including S. hematobium * S. mansoni may be assiseiated with relapsing non-typhoid Salmonella septicemia

Answer 107

* Filiariasis * *Wuchereria bancrofti* * 90% of ~120 million cases * "all over the tropics: Africa, India, SE Asia, Pacific Islands, Caribbean & South America" * *Brugia malayi* * **restricted to southeast Asia, with closely related *Brugia timori* in southeastern Indonesia * Onchocerciasis - River Blindness * *Onchocerca volvulus*

Answer 108

* Definitive Host: Human * Intermediate Host: Mosquito 1. Mosquito takes a blood meal, L3 larvae enter skin. 2. Adults in lymphatica 3. Adults produce **sheathed** microfilariae that migrate into lymph and blood channels 4. Mosquito takes a blood meal ingests microfilariae 5. Microfilariae shed sheaths, penetrate mosquito's midgut and migrate to thoracic muscles 6. L1 larvae (sausage larvae) 7. L3 larvae 8. Migrate to head and mosquito's proboscis

Answer 109

* Vectors for *Wucheria bancrofti,* filiariasis * Anopheles gambiae (bottom left) in sub-Saharan Africa * nocturnally periodic * *Culex* (generally *quinquefasciatus*) (bottom right) in Americas, Asia, east Africa * *Mansonia uniformis (top right)* in Papua New Guinea * *Aedes* species (top left) * diurnally subperiodic in Pacific and Asia * nocturnally subperiodic in Thailand

Answer 110

* *Wucheria bancrofti microfilarial stage* * *sheathed larvae* * *nuclei stain purple and are sharply defined* * *nuclei do not extend all the way to the tip of the tail* * *sheath is stained a paler colour*

Answer 111

* *Brugia malayi* microfilaria * sheathed * usually 'kinked' picture on left * tail tapered with significant gap between terminal nuclei and two discrete sub-terminal nuclei (right) * *Mansonia* (open swamp) * *Aedes* * filiariasis, about 13 million people, 10% of worlds total

Answer 112

* *W. bancrofti (left)* * *sheath does not stain* * *nuclei stain deep blue* * *(can't see here but nuclei don't go all the way to the end of the tail)* * *B. malayi* * *deep purple staining nuclei* * *pink staining sheath* * *(can't see here but two distinct terminal nuclei separate from the rest, go all the way to the end of the tail)*

Answer 113

* vast majority assymptomatic but almost all have sub clinical lymphatic damage * 40% have renal involvement with proteinuria and haematuria 1. Asymptomatic Infection (Lymphatic Dilatation) 2. Acute Lymphadenitis and Filarial Fevers 3. Elephantiasis 4. Tropical Pulmonary Eosinophilia (TPE)

Answer 114

* Filarial worms have evolved to have diurnal cycle coincident with biting habits of their regional vector * **nocturnally periodic**: * *W. bancrofti* Sub-Saharan Africa vector is usually malaria mosquito *Anopheles gambiae*, which generally bites at night, so midnight is preferred time for blood collection * In the Pacific and Asia, the Vector is a **diurnally supperiodic** form of *Aedes*. Microfilaria are present all the time but are at peak blood levels between 10 am and 2 pm * in Thailand it is a **nocturnally subperiodic** form

Answer 115

* rapid Ag detection test for W. bancrofti using polyclonal and Mab's * Sensitivity 96% * no cross-reactions with other human infective filariae * finger prick blood, any time of day without regard to periodicity of parasitie

Answer 116

* Loa Loa * microfilaria 250-300 µm long * sheathed, column of irregularly spaced nuclei extends to tip of tail, which is often bent to one side * species has diurnal periodicity so blood levels highest between 10 am and 2 am * vector is day biting fly *Chrysops*

Answer 117

* *Chrysops* fly, vector for *Loa Loa* * fly breeds under rainforest canopy and in mud at side of streams, more common in rainy season * rubber plantations bring humans into contact vor work, so more exposure in adults than kids * West Africa affecting Nigeria, Cameroon, Zaire, Angola, Gabon, Chad, South Sudan and Central African Republic * Overlaps with distribution of *Filiarisis and Onchocerciasis* and complicates community treatment plans. *Loa Loa* is relatively assymptomatic, but treatment with Ivermectin may precipitate encephalitic crisis through killing *Loa Loa* microfilaria.

Answer 118

* Definitive Host: Human * Intermediate Host/Vector: Chrysops Fly (Deer Fly) * 3 larval stages, microfilariae 1. *Chrysopos* takes a blood meal, L3 Larve enter bite wound 2. Adults in subcutaneous tissue 3. Adults produce sheathed microfilariae that are found in spinal fluid, urine, sputum, peripheral blood and lungs 4. Fly takes a blood meal, injesting microfilariae 5. Microfilariae shed sheaths, penetrate fly's midgut, migrate to thoracic muscles 6. L1 (sausage) Larvae 7. L3 Larvae 8. Migrate to head and fly's proboscis

Answer 119

* *Mansonella perstans* * a nematode of minor medical importance * does not cause many symptoms but worm can swim about the pericardium and peritoneum and produce some swelling * **unsheathed** * 190-200 µm long * tail blunt and nuclei extend to tip of tail * smaller than other species of microfilaria * Lifecycle * similar to *W. bancrofti, B. malayi* except vector/intermediate host is midge (genus *Culicoides*)

Answer 120

* coinfection in endemic area with * *W. bancrofti and* * *M. perstans* * coinfections usually involve *Mansonella* and another genus * size difference easily seen, sheath visible on larger *W. bancrofti*

Answer 121

* by ingesting unpasteurized milk products * eating raw liver or meat of infected animals * inhalation: farms or labs * contact with parturient animals * contact of skin or conjunctiva with soiled surfaces * other: human breast milk * sexual transmission * blood broducts, bone marrow transplanatation

Answer 122

* The goal of the draft global action plan is to ensure, for as long as possible, continuity of successful treatment and prevention of infectious diseases with effective and safe medicines that are quality-assured, used in a responsible way, and accessible to all who need them. * To achieve this goal, the global action plan sets out five strategic objectives: 1. to improve awareness and understanding of antimicrobial resistance; 2. to strengthen knowledge through surveillance and research; 3. to reduce the incidence of infection; 4. to optimize the use of antimicrobial agents; and 5. develop the economic case for sustainable investment that takes account of the needs of all countries, and increase investment in new medicines, diagnostic tools, vaccines and other interventions.

Answer 123

* Malaria (cerebral or otherwise) * typhoid * pneumonia * urinary tract infection * otitis media/sinusitis * severe pediatric gastroenteritis * brucellosis * rickettsial disease * subarachnoid hemorrhage * cerebral abscess or other SOL including tuberculoma * causes of lymphocyti CSF (TB, cryptococcus, viral meningitis etc) * encephalitis * poisoning (alcohol, drugs, etc.) and other causes of coma * drug-induced extrapyramidal signs (phenothiazines, antiemetics)

Answer 124

* pyogenic * bacterial * lymphocytic with normal glucose * most viruses (polio, enteroviruses, coxsackie, arboviruses) * rickettsiae * HIV * early TB * misc (eg endocarditis, neoplastic) * lymphocytic with low glucose * partially treated bacterial meningitis * cerebral abscess * TB * some viral (eg mumps) * fungal (eg cryptococcus, aspergillus) * brucellosis * syphilis * leptospirosis * trypanosomiasis * Eosinophilic * angiostrongylus cantonensis (rat lung worm) * taenia solium (cysticercosis) * paragonomiasis * amebic (rare) * naegleria or balamuthia mandrillaris

Answer 125

* cranial nerve palsy * hemiplegia * deafness * subdural empyema * abscess * late hydrocephalus

Answer 126

* Polysaccharide vaccines do not provoke T-cell immunity and therefore **their effect does not provoke the formation of either memory B or memory T cells**. The consequent lack of an anamnestic response means that a second or subsequent exposure to that same meningococcal polysaccharide antigen fails to induce the production of an appropriate antibody. Thus polysaccharide vaccines * lose their effect fairly rapidly, * need to be repeated every 3 years, and * fail to induce a satisfactory response in the young (0–5 years). * Furthermore every subsequent vaccination starts from scratch and this is technically not a booster\*. * Repeated vaccination with polysaccharide meningococcal A/C vaccine may well give reduced functional antibody responses to the serogroup C portion of the vaccine despite increased responses to the serogroup A. These vaccines should always be transported via a cold chain with the temperature kept below 5 °C. \* The term ‘booster’ implies stimulation of dormant immunogenicity by a repeat immunization. Repeat polysaccharide vaccines are therefore not boosters. * less effective in malnourished, malaria, HIV * aborts epidemics but not nasal carriage

Answer 127

* ***S. pneumoniae*** is the commonest cause of pyogenic meningitis worldwide at any age, including those in the 0–14 year age group. It is certainly the most common cause of bacterial meningitis in adults, and the second most common cause of all types of meningitis in children older than age 2 years (after viral causes). ***H. influenzae*** seldom affects children over 5 years of age. Some pathogens are more common in some places rather than in others. For example – in Vietnam – ***Streptococcus suis*** is the most common cause of pyogenic meningitis in adults. ***Staphylococcal*** meningitis (S. aureus or coagulase negative staphylococci) is usually the result of haematogenous spread from elsewhere or develops as a complication of a surgical procedure. * ***Listeria*** can affect older people as well as neonates.

Answer 128

* Serotype A causes the majority of cases of meningococcal meningitis in Africa and, indeed, worldwide. * Some serotypes are more prevalent in certain areas, e.g. serotype C in South America, serogroup Y in the US. * W135 has become an important cause of meningitis in recent times with outbreaks reported in Burkina Faso, in the African meningitis belt and isolated cases in South Africa. It was responsible for a large outbreak in pilgrims returning from the Hajj in 2000 when it was transported back to many countries including the UK. The authorities in Saudi Arabia now insist on immunization, within 3 years, with conjugate vaccine against this strain in all those going to do the Hajj or Umrah pilgrimages. Note that of the 13 types of Meningococcus described (all Gram negative cocci) only 6 are pathogenic viz. serotypes A, B, C, Y, W135 and X. Vaccines are now available against all these except serotype X. * In Europe and Canada serotype B has become most dominant since the introduction of quadrivalent ACWY vaccine.

Answer 129

* Streptococcus pneumoniae • many serogroups (numbers) * Neisseria meningitidis * serogroups A, B, C, Y, W135 * A, W135 in Africa, A much reduced in areas where Men A vaccine introduced * B in Europe & Canada after introduction of quad vaccine (A, C, W, Y) * Y in US * Haemophilus influenzae type b • many children \<5y * S. suis in Thailand, Vietnam * Staph and Listeria in elderly, immunocompromised

Answer 130

* see below * alert threshold is \>15 cases per 100,000, i.e. 2 or more cases in a camp of 10,000 people * other features suggesting an epidemic are shift from \<5 to teenagers or older esp in high risk situation * eg refugee camp in meningitis belt in dry season * if more than 3 yrs since last epidemic then alert threshold reduced to \>10/100,000

Answer 131

* early recognition is key * group vaccinations of appropriate vaccine according to serotype * mass chemoprophylaxis if org sulfa-sensitive or if decision to use fluoroquinolone

Answer 132

* blood cultures and csf early to identify organism * antibiotics ASAP, initially broad spectrum and take account of local sensitivities * ceftriaxone has supplanted most others, but chloramphenicol and tifomycin (long-acting chloramphenicol) may still be only options in some resource poor settings. * in areas of high antibiotic resistance to pneumococcus such as Thailand or Vietnam, vancomycin should be added pending culture and sensitivity. * Steroids * although evidence of reduced disability in some settings in high-income settings, studies do not show same benefit of routine use for pyogenic meningitis in resource-poor settings. * studies with glycerol have shown no benefit

Answer 133

* although responsive to benzyl-penicillin and chloramphenicol, ceftriaxone now widely available and drug of choice * uncomplicated meningococcal meningitis has mortality of \<10% and rarely needs more than 5-7 days treatment * meningococcal septicemia +/- meningitis has mortality \>40%, needs max intensive care * up to 10% have immune complex disease inc uveitis, pericarditis, polyarthritis, usually in second week, can be treated with nsaids or steroids * Contact treatment * cipro (or rifampicin or ceftriaxone) single dose can be given to contacts * 'ring' vaccination of contacts may be more appropriate in epidemic situation

Answer 134

* choice of antibiotic depends on local resistance patterns * high rates of penicillin resistance, in some settings chloramphenicol resistance * eg PNG, Thailand, Vietnam (nb also p. suis) * High dose ceftriaxone eg. 2 gm im or iv bid * add vancomycin or give Meropenem if available in cases of P&C resistance * treat **minimum 10 days, possibly 14+ days** * up to 40% of survivors will have neuro deficits

Answer 135

* TPE is an asthma-like condition due to an exaggerated immunological response to the common filarial parasites Wuchereria bancrofti or Brugia malayi. Sometimes the acronym **TFPE** is often used with the ‘F’ standing for ‘filaria’. TFPE shows a marked eosinophilia. However a similar high eosinophil count is found in TPE from other causes e.g. when associated with worms migrating through the lungs such as Ascaris,hookworm and Strongyloides. Although TPE starts as an acute lung condition, it may ultimately progress to a chronic restrictive lung disease with a decrease in pulmonary diffusion capacity. Chronic TPE develops most often in people under 40 years of age. It occurs in less than 0.5% in those \>40 years of age. The condition usually presents with persistent coughing, wheezing (especially at night) and systemic signs such as mild fever and weight loss. It is due to an allergic hyper-responsiveness to dead and dying microfilariae in the lungs. TPE should be suspected in immigrants with these symptoms even if they have left endemic countries many years ago. Misdiagnoses of acute-onset asthma or even of a recrudescence of latent TB have been made in these patients. If the patient fails to respond favourably to a 3-week course of diethylcarbamazine (DEC) then a second course should be given together with three weeks of albendazole. Alternatively doxycycline may be used for several weeks, followed by ivermectin. TPE is commonly seen in West Africa and India. * In true TFPE, apart from a peripheral blood eosinophilia of \>3000cells/μl, a massive rise in IgE is typical. The usual person who presents with TFPE is a young adult male from India. TFPE is one manifestation of ‘occult filariasis’. Other organs affected by occult filariasis are the kidneys (glomerulonephritis), the heart (fibrosis), the large joints (especially the knee) and the breast (granulomata).

Answer 136

* Loeffler’s syndrome was originally described in 1932 by Wilhelm Loeffler as an acute eosinophilic pneumonia due to a reaction to a variety of parasites that normally migrate through the lungs e.g. Ascaris lumbricoides, Strongyloides stercoralis and hookworms such as Ancylostoma duodenale and Necator americanus (See Chapter 24, Section B, Q2). Although TFPE broadly fits into this definition the history is almost always that of chronic lung dysfunction rather than that of an acute transient pneumonia. Using this definition Loeffler’s syndrome affects only a very small proportion of those living in filarial endemic areas. * Note: many nowadays include any lung disease in which eosinophils accumulate in the lungs due to a parasitic infection under the heading of Loeffler’s syndrome.

Answer 137

* Leptospirosis is a biphasic disease that begins suddenly with fever accompanied by chills, intense headache, severe myalgia (muscle ache), abdominal pain, conjunctival suffusion (red eye), and occasionally a skin rash. * The symptoms appear after an incubation period of 7–12 days. * leptospira species * contact with water * Widespread, temperate and tropical, more common tropical

Answer 138

1. CSF pressure varies from 10 cm H2O in children to 20 cm H2O in adults 2. Glucose concentration is only two-thirds that of plasma and is further reduced in bacterial infections. 3. CSF is free from white blood cells apart from a few lymphocytes. 4. The protein content should be \<10 mg/ml. 5. The pH of the CSF is slightly acidic compared to that of plasma and remains surprisingly constant despite wide pH variations in body fluids.

Answer 139

* The GCS is based on best motor responses, best verbal responses and eye opening. The maximum for each is 6, 5 and 4 respectively, viz. a total of 15. Unrousable coma occurs with a score \<9 and is a contraindication to LP. Although it is useful in diagnosing and differentiating the different types of meningitis, an LP should not be performed within 2 h of a convulsive seizure. Considerable clinical acumen is often needed in deciding when and when not to do a lumbar puncture. Many patients with raised CSF pressure will either have equivocal, marginal or actually no papilloedema. In many places a CT scan may not be available.

Answer 140

1. A moderate to high neutrophilia and chronic fever, worst in the evening, is found in deep sepsis, e.g. subphrenic abscess, hepatic abscess. 2. The invasive stage of schistosomiasis is often, but by no means always, accompanied by a marked eosinophilia not a neutrophilia. 3. TB and 4. brucellosis frequently show a neutropenia.

Answer 141

* Always beware of TB in such patients. Pulmonary examination may be negative but many co-infected patients have extrapulmonary TB. In HIV, fever only accompanies an acute attack or HIV seroconversion, where symptoms resemble infectious mononucleosis (IM) and IM-like syndromes, e.g. cytomegalovirus and toxoplasmosis. Opportunistic infections, e.g. thrush, P. jirovecii, nontyphoid salmonellosis, Kaposi changes and intractable candidiasis will occur once the CD4 count drops below 200 x 106/L.

Answer 142

* Evidence of preceding Strep pyogenes infection + two major or one major and 2 minor manifestations * Major manifestations * carditis * polyarthritis * chorea * erythema marginatum * subcutaneous nodules * Minor manifestations * arthralgias * fever * elevated ESR or CRP * EKG evidence of prolonged PR interval

Answer 143

* Pastia's Lines * Pastia's sign, Pastia lines, or Thompson's sign is a clinical sign in which pink or red lines formed of confluent petechiae are found in skin creases, particularly the crease in the antecubital fossa, the soft inside depression on the inside of the arm; the folding crease divides this fossa where the forearm meets the (upper) arm (the biceps, triceps, humerus section of the upper extremity); the inside of the elbow (the inside flexor depression (fossa) of the elbow. It occurs in patients with scarlet fever prior to the appearance of the rash and persists as pigmented lines after desquamation.

Answer 144

* salicylates first-line agents - ie. ASA * 80-100 mg/kg/day to target plasma concentrations 200-300 mg/L * after 2 wks reduce to 60-70 mg/day for 3-6 wks. * do not shorten analgesic and anti-pyretic * treat heart failure with bed rest and corticosteroids * diuretics, dig, captopril for more severe * Chorea usually self limiting * treat haloperidol * steroids ? IVIG, plasmapheresis * secondary prophylaxis with antibiotics long term, 5 yrs with mild carditis, 10 yr or lifelong with chronic carditis

Answer 145

* Koplik’s spots—small white lesions on the buccal mucosa, might be visible during the prodrome * incubation period 7-21 days * rash usually starts 4 days after onset fever, lasts 3-5 days * Fever, cough, coryza, and conjunctivitis * Malnourished children: pigmented rash that desquamates during recovery. In uncomplicated measles, clinical recovery begins soon after appearance of the rash * Complications in up to 40% of patients due to immune suppression. Risk of complication in very young and malnourished

Answer 146

* Noma is a “gangrenous affection of the mouth, especially attacking children in whom the constitution is altered by bad hygiene and serious illness especially from eruptive fevers, beginning as an ulcer of the mucous membrane with edema of the face extending from within out, rapidly destroying the soft tissues and the bone and almost always quickly fatal”. The term noma originates from the greek word “nomein” which means to devour or to graze. * terrible complication of measles in malnourished kids

Answer 147

* Family:Paramyxoviridae * Genus:Morbillivirus * Species:Measles morbillivirus * Measles virus (MeV) is a single-stranded, negative-sense, enveloped (non-segmented) **RNA virus** of the genus Morbillivirus within the family Paramyxoviridae.

Answer 148

* Rickettsia prowazeki * Disease * headaches, prostration, chills, coughing and severe muscular pain CFR 40% without treatment * treatment with tetracycline and chloramphenicol antibiotics * Transmission by the vector Louse ingests Rickettsia ⇒ invade midgut epithelium and multiply ⇒ rupture into gut lumen ⇒ high numbers in gut faeces infection occurs through the conjuctiva or by inhalation of louse faeces faeces may remain infective for \>70 days * Epidemiology Mainly occurs in colder regions of Africa and S/C. America Humans only reservoir (sylvatic cycle in Americas?) Can occur in epidemics (Burundi 1997- 100,000 cases) asymptomatic carriers- recrudescences (Brill-Zinsser disease) leading to epidemic

Answer 149

* Bartonella quintana * milder than typhus; ‘rare’, but in immunocompromised hosts 5-day relapsing fever, severe persistent pain in legs * treatment with doxycycline, erythromycin, or azithromycin * Transmission bacteria remain in the gut lumen and do not kill the **louse** infection via faeces * Epidemiology cosmopolitan distribution associated with socially disadvantaged Re-emerging disease? – found in homeless in France, US, Japan and Russia

Answer 150

* Borrelia recurrentis * Disease Restricted/ rare, though seen immuno-compromised hosts Neurological involvement common – mild neck stiffness, headache Severe disease with 2-5 % CFR even after antibiotic treatment * Transmission Louse ingests spirochaetes in host blood All spirochaetes leave the louse’s gut into haemocoele and multiply greatly The louse survives Human infection occurs after the louse is killed - e.g. crushed by human, releasing spirochaetes that infect via mucosa, cuts, etc (not in faeces, not by bloodfeeding) * Epidemiology formerly cosmopolitan Today, restricted to Ethiopia with outbreaks traced back to here (e.g. South Sudan)

Answer 151

* Yersinia pestis * Xenopsyalla cheopsis (oriental rat flea) or Pulex irritans var hominis (human flea) * Insecticidal control of fleas must precede or at least be coincident with rodent control * Xenopsylla control * residual insecticide spraying of domestic rat runs and burrows * during outbreaks, treat all dwellings \< 200m of affected one * a range of insecticides available, but resistance is common * for wild rodent fleas, insecticide in bait boxes (e.g. bamboo tubes) * Volatile insecticides inside freight containers on ships * Rodent control * • domestic * – rodenticides (e.g. warfarin, many others) – rodent chemosterilization (long term) * • wild * Hydrogen cyanide (HCN) or methyl bromide gas

Answer 152

* These two species are morphologically identical – only distinguish this based on where they are found (on head or in clothes) * Only the body louse transmits disease. They transmit -Louse-borne epidemic typhus, Trench fever and Epidemic relapsing fever. All can be treated with antibiotics * Frequently change/wash clothes. Insecticide powder

Answer 153

1. Quarantine cases of pneumonic plague 2. Diagnose and treat with antibiotics 3. Kill the fleas (this must be done before you tackle the rodents). Use insecticides (but pyrethroid resistance now common) and apply to rodent burrows and rat runs. During outbreaks, treat all dwellings \< 200m of affected one 4. Use rodenticides * Antibiotic resistance, insecticide resistance

Answer 154

* Cell Wall * Beta lactam * vancomycin * DNA/RNA synthesis * fluroquinolones * rifamycins * folate synthesis * trimethoprim * sulfonamides * cell membrane * Daptomycin * protein synthesis * linezolid * tetracyclines * macrolides * aminoglycosides

Answer 155

* currently about 700,000 (low estimate) * predicted 10 million, would dwarf most other causes (cancer currently 8.3 million)

Answer 156

* accumulation of inherently-resistant bacteria * mutant selection, sometimes during therapy * spread of resistance genes among bacteria * spread of resistant strains amoung humans * Darwinian evolution * the level of antibiotics in an environment selects for those organisms resistant to the antibiotic

Answer 157

1. transformation: transfer of DNA from a dead bacterium to recipient 2. conjugation: transfer of a plasmid or conjugative transposon from a donor bacterium to recipient 3. transduction: transfer of a gene from a bacterium infected with a virus via delivery system

Answer 158

* Commonest * TB * Strep pneumonia * Non-typhoidal salmonella * **Then** * ****E. coli * Klebsiella sp * Other Enterobacteriaceae * S. aureus * other strep/enterococcus * Fungus * In High HIV prevalence areas? * non-typhoid salmonella, e.g. *Salmonella typhimurium*

Answer 159

* •TB * •Brucellosis * •Leptospirosis * •Rickettsia * •Viruses * •Vhf * •Influenza * •Arbovirus * •Fungi * •Histoplasma * •Penicillium marneffei

Answer 160

* lack of surveillance or of accurate diagnostic tools means we don't know what the non-malaria causes of febrile illness are * nor drug susceptibility patterns * necessitates increasing use of broad spectrum antibiotics, which drives continuing resistance ...

Answer 161

* in high burding settings, MTBBSI is leading cause of death in hospitalized PLWHIV * presentation v different to 'classic' TB * Dx difficult but earlier treatment important to reduce mortality * Urine Based rapid diagnostics huge breakthrough * Use clinical judgement about empirical therapy and factor risk of dying into that decision * prognosis is poor, but possibly slightly better with good supportive care and empirical treatment

Answer 162

* TB * the major killer of adult inpatients in South Africa * "disseminated" in 90% of post mortem cases * in public hospital in Cape Town, microbiologically-confirmed TB found in 1/3 of **all** HIV-positive acute adult medical admissions

Answer 163

* Altered clinical presentations of TB * increase in smear neg pulmonary disease * increase in extra-pulmonary/disseminated forms * sputum smear microscopy less sensitive during HIV infection * typical and atypical CXR features depending on severity of immunosuppression * Sensitivity **about** 79% and specificity 50% * Sensitivity depends on prevalence of TB varying from 98% with 5% prev to 90% with 20% prevalence

Answer 164

* Signs & Sx * Cough, Fever, Sweats, Weight Loss * Wasting * inability to walk unaided * Pallor * doughy, tender abdomen * lymphadenopathy * fever, but rigors less common * raised RR (but remember PCP) * Blood results * Low CD4 * **anemia - good predictor:** Hepcidin sequesters Fe extracellularly, hepatocytes, RBC Fe to macrophages, decreased GI absorption * low platelets * hyponatremia * low albumin * lactic acidosis * low monocyte count * most patters of LFT derangement * Renal dysfx

Answer 165

* CXR: miliary pattern, mediastinal nodes * US spleen: microabscesses * US abdomen: lymphadenopathy * (Cavitation on CXR **not** typical finding)

Answer 166

* Blood cultures NOT helpful: too slow, expensive, often not available * Urinary LAM or Gene Expert better than sputum * Gene Xpert on concentrated Urine or sputum * Blood LAM or Gene Xpert has low yield, is not sensitive

Answer 167

* same as for TB

Answer 168

* Yersinia pestis: cause of plague * Y. pseudotruberculosis/Y. enterocolitica * enteropathogenic strains * Gm -ve (1-3µm) bipolar staining bacillus belonging to Enterobaceriaceaa

Answer 169

* zoonotic infection "rodent disease affecting humans" * transmitted by flea bites on skin (Xenopsylla cheopsis) or ingestion of infected animal materia (guinea pigs in Peru, camels in Asia) * most important reservoirs Rattus rattus (black), R. norvegicus * other urban and sylvatic rodents * marmots, chipmunks, squirrels * rodents tolerate plague, develop long term bacteremia allowing fleas to transmit * **Man is accidental host in cycle** * only pneumonic plague is transmitted man to man

Answer 170

* flea ingest blood from bacteremic reservoir, blood 'clots' in foregut, blocking flea's swallowing * regurgitates organisms into skin and blood stream while feeding again * bacteri migrat by cutaneous lymphatics to regional lymph nodes * bacilli phagocytosed, resist destruction and divide. Lysis of neutrophils release bacteria * Lymph nodes necrotic with large # bacilli and neutrophils

Answer 171

* incubation 2-7 days * malaise * high fever * pain or tenderness over lymph nodes, enlarge to be called buboes * bacteremia initially intermittent then constant * DIC * shock, convulsions * "black death" diffuse, hemorrhagic changes in skin and cyanose from necrotizing pneumonia give rise to dark skin at extremities * Presentations: 1. bubonic plague 2. septicemic plague 3. pneumonic 4. meningitis

Answer 172

* most common presentation (80-95%) * fever and painful nodes * invubation 2-8 days after bite * bacteria divide in regional lymph nodes * sudden onset fever, chills, weakness, headache at same time or just after developing bubo * Bubo * intense pain over lymph nodes, usually groin, axillae, neck * warm, edema, smooth or irregular non-fluctuant masses * tender * death btw 2-4 days * skin lesions unusual \<25% can be pustules, vesicles, papules, eschar * purpua may become necrotic leading to distal gangrene * 5% hematogenous spread to lungs - pneumonic plague * **Mortality 50-90% if untreated**

Answer 173

* 20-25% of cases * no bubo, massive growth of bacilli * without tx 100% mortality * with tx 15-20% mortality * death rapid

Answer 174

* spread by aerosol inhalation * 5% hematogenous * high mortality, very contagious * only human-human form * incubation 1-2 days, death can be within 24 hrs * fever, lymphadenopathy, cough, chest pain, **hemoptysis** * 100% mortality without tx, 50% with

Answer 175

* more uncommon, usually week or so after inadequately treated bubonic plague * usually associated with axillary nodes * v. unusual to present without previous lymphadenitis * clinical: fever, headach, meningism * csf: pleocytosis, pmn's, bacteria gm stain

Answer 176

* consider in endemic area, e.g. Madagascar, Western US * neutrophilia, leukemoid rxn, esp kids * DIC, hepatorenal failure * microbiological: * aspirate bubo and gem stain for cocco bacilli - Safety pine apppearance * Wayson's stain - fuschin + methylene blue * innoculate on MacConkey agar * serologica testing

Answer 177

* plague bacteria * gm -ve coccobaccilli * safety pin appearance

Answer 178

* supportive * iv fluids, oxygen, I & d bubo prn * Antibiotics: 50% mortality without, 5% with 1. Streptomycin 2. Gent + tetracycline as effective 3. doxycycline x 7 days 4. if meningitis add chloramphenicol 5. cipro/tetracycline/co-trimoxazole * **Penicillin completely ineffective**

Answer 179

* yes but not licenced, unpleasant reactions * prophylaxis with cotrimoxazole, tetracycline recommended by WHO x 7 days for exposure * CDC added cipro for biological threat

Answer 180

1. S. typhoi - typhoid fever 2. S. paratyphi - paratyphoid fever 3. Non-typhoidal salmonella * S. typhiumriu * S. enteridis * 1 & 2 are host specific, invasive orgs with rel high mortality * 3 are generalists and cause enteric/diarrheal disease with rel low mortality

Answer 181

* incubation 7-14 days * wk 1: * slowly rising step-wise fever * headache, abd pain, vomiting, cough, malaise * wk 2 * high grade fever ~40⁰ C * obvious abd sx * diarrhea or constipation * hepatomegaly, splenomegaly * Rose spots (30%) * wk 3 * complications 10-15%: intestinal bleeding & perf, pneumonia etc * wk 4 * advanced illness: apathetic expression ("typhoid facies"), agitated delirium

Answer 182

* blood culture, culture rose spots * blood culture may be neg due to low numbers of orgs * RDT * Widal test: agglutinating ab against O lipopolysaccharide ag, H flagellar ag, Vi capsular ag * WBC normal, plts normal * liver fx mildly elevated

Answer 183

* Fever without focus * malaria * rickettsia * dengue * leptospirosis * brusellosis * trypanosomiasis * Fever with focus * rti * tb * cns infection * deep abscess/amebic liver abscess * infectious hepatitis * Non-infective * lymphoproliferative/CT diseases

Answer 184

* 70-90% as OP * general supportive * oral rehydration * antibiotics * inpatient care * oral or iv rehydration * abx * +/- icu * +/- pressure area care * +/- surgery * +/- blood transfusion * +/- steroids * Antibiotics * Fluroquinolones very effective in susceptible infections, probs with resistance * ceftriaxone, cefixime slow response to treatment but little resistance * azithromycin excellent intracellular penetration, resistance rates unclear * **nb emergence of ESBL resistance in Pakistan, India etc** * nb steroids improve survival in severe and complicated disease

Answer 185

* gi bleed * perforation * encephalopathy, shock * hepatititis * cholecystitis * myocarditis * psychiatric * bone and joint * meningitis * pneumonia * anemia * DIC * Relapse: chronic carriage (\>1yr) * ca gallbladder

Answer 186

* prolonged course of Abx * guided by sensitivity * if gallstones, consider cholecystectomy

Answer 187

* Life threatening organ dysfunction due to a dysregulated host response to infection * final common pathway for mortality due to many infectious diseases * 31.5 million sepsis cases/yr * 5.3 million deaths

Answer 188

* syphilis * non-venereal treponematoses * leptospirosis * Lyme: Borrellia burgdorffi * Rat Bite Fever, Asian Form Sodoku: Spirillum minus (North American form is Streptobacillus moniliformis) * Relapsing Fevers: Borrelia recurrans, B. duttoni and others

Answer 189

* Leptospira interrogans * Slender spiral anaerobic rods * can be seen microscopically * unclear virulence factors * **Serology most useful method of diagnosis** * ****MAT (micro agglut test) * x reacts with spirochetes and legionella * Elisa IGM, PCR may be an option * Culture specimens but slow * blood, csf, urine

Answer 190

* The most common and widespread zoonosis in the world * Leptospira interrogans has 250 serovars * natural host mammals of all kinds, widespread in rats * animals can develop clinical disease, 10% mortality in dogs * animas shed organism in urine for weeks/months after infection * can stay viable for months

Answer 191

* exposure to water or infected animals * occupational: 30-50%: farmers, abbatoir workers, vets, sewer workers, rice farmers, military personnel * recreational: fresh water exposure, swimmers, canoists, fishing * Household exposure: dogs, domest. livestock, rodent exposure * Epidemic after floods eg phillipines

Answer 192

* after entry multiplies in blood and tissues, affects any organ esp liver and kidneys * Kidneys: intertitium, tubulo-interstitial nephritis * Liver: centrilobular necrosis. Proliferation in Kupffer cells, jaundice and hepatocellular dysfx * skeletal muscle: necrosis with severe disseminated vasculitis * Eye: recurren uveitis

Answer 193

* 15-40% assymptomatic, maybe more, poss flu-like illness, incubation 7-12 days (2-20) * 90% mild anicteric, usually self limiting * Biphasic: * leptospiremic and leptospiuric * brief period of 1-3 days between 2, some improvement, temp settles, pt improves * then fever recurs, antibodies detected and org isolated from urine * **_Meninges, liver, eyes, kidney_** * Anicteric vs Icteric * **Anicteric:** aseptic meningitis in 50%, cranial nerve palsies, encephalitis, mild delirium * meningitis usually 1-2 days, may last 1-2 wk * abd pain with diarrhea or constipation, hepatosplenomegaly, n,v, anorexia * Uvietis 2-10% * subconjunctival hemorrhage most common ocular complication * renal, pulmonary sx, adenopathy, rashes, muscular pain * **Death extremely rare in anicteric** * Icteric: Weil syndrome * jaundice, renal dysfx, hepatic necrois, pulomnary dysfx and hemorrhagic diathesis (\<5%) * Jaundice may persist for weekes, may lead to renal failure, hemorrhagic diathesis, multi organ failure, ARDS, hemolysis, hemoptyisis * also splenomegaly, myocarditis, chf, myocarditis and pericarditis * Mortality rate 5-10 % worse with age up to 50%

Answer 194

* dengue, lassa, hantavirus and other VHF * viral hepatitis * malaria * meningitis * EBV, CMV * HIV * rickettsial disease * typhoid fever

Answer 195

* mild doxy, amoxil * severe: parenteral penicillin, cephalosporins or erythromycin * doxy prohylaxis weekly for short term exposure * steroids? -inclonclusive * Jarisch-Herxheimer rxn may develop

Answer 196

* good sanitation, prevent livestock urine from entering water * control leptospira in pets and lifestock * disinfect contaminated work areas * worker education * pretective equipment * case finding in suspected outbreaks * identify infected areas and avoid exposure where possible * following floods in areas where known exposure consider administering weekly doxycycline: prophylactic abx

Answer 197

* multisystem inflammatory disease caused by sprirochetes Borrelia burgdorfi (NA, Europe, Asia) * caused by 4 other species in Europe and Asia * B. lonestari - NA * B. afzelli, B. garinii, B. valaisaiani

Answer 198

1. early localized 2. early disseminated 3. late chronic 4. post-Lyme

Answer 199

1. Early localized * **Erythema migrans (EM)** * 90%, usually within 1 month of bite, only 3O% recall bite * Constitutional: viral syndrome, local.general lymphadenopathy, arthralgia, myalgia, headache, neck stiffness, lethargy fever, malaise 2. Early disseminated disease * days to months after infection * Carditis: 8% of untreated Lyme * any degree of heart block and any form of myopericarditis * majority resolves before tx 3. Neurologic manifestations * approx 10% * lymphocytic meningitis (resolves spontaneously) * cranial nerve palsies, esp VII, can be bilateral * radiculoneuritis * Cutaneous manifestation: Borrelial lymphocytoma, usually resolves with treatment 4. Post Lyme Syndromes (chronic Lyme) * fibromyalgia common * headache * CFS

Answer 200

* serology to confirm dx, not a screen * tx: early localized: * amoxil, doxy, cefuroxime * late disease doxy

Answer 201

* arenavirus, ss RNA * zoonotic, multimammate rate excretes virus in urine for extended period * transmission: ingestion/direct contact/?inhalation of aerosol * 100-300,00 infections each year * high inpatient mortality and nosocomial transmission with h to h spread * seasonal in Sierra Leone and Nigeria * highest incidence in dry season (nov-apr)

Answer 202

* suspected case: * illness with gradual onset of malaise, fever, headache, sore throat, cough, nausea, vomiting, diarrhea, myalgia, chest pain, hearing loss * hx of contact with rodent excreta or a case of Lassa fever * confirmed case: * suspected case that is lab confirmed * +ve IgM ab, PCR or virus isolation, or epidemiologically linked to confirmed case

Answer 203

* incubation 6-21 days * Stage 1 (d1-3) * gen weakness and malaise * high fever, \>39 constant with peaks of 40-41 * Stage 2 (d4-7) * sore throat (white exud patches) v common * headache, back, chest, side or abd pain * conjunctivitis * n&v, d * prod cough * proteinuria * low bp (sytolic \<100 mmHg) * anemia * Stage 3 (d7+) * edema face and neck * convulsions * mucosal bleeding (mouth, eyes, nose) * internal bleeding * encephalopathy with confusion or disorientation * Stage 4 (d14+) * coma * death * Complications * sn hearing loss in 30%, no relation to severity * during convalescence transient alopecia and ataxia * more severe in pregnancy (80% fetal loss in 3rd trimester)

Answer 204

* early lab: lymphopenia, thrombocytopenia * fatal lassa associated with Age, acute kidney injury, AST\>150 and high VL * Def dx 1. rev transcriptase pcr assay 2. ab ELISA 3. ag det tests 4. virus isolation by cell culture * tx Ribavirin + support, antipyretic * early dx critical as tx \>7 d asstd higher mortality * nb recent jan-mar outbreak in Nigeria

Fever and microbiology Flashcards

(249 cards)