infectious diseases Flashcards

Question

what is infectious mononucleosis and what are its features

Answer 1

Infectious mononucleosis (glandular fever) is caused by the Epstein-Barr virus (also known as human herpesvirus 4, HHV-4). It is most common in adolescents and young adults. Features: ``` sore throat lymphadenopathy pyrexia malaise, anorexia, headache palatal petechiae ``` splenomegaly - occurs in around 50% of patients and may rarely predispose to splenic rupture hepatitis presence of 50% lymphocytes with at least 10% atypical lymphocytes haemolytic anaemia secondary to cold agglutins (IgM) a maculopapular, pruritic rash develops in around 99% of patients who take ampicillin/amoxicillin whilst they have infectious mononucleosis

Answer 2

URTI symptoms + amoxicillin → rash ?glandular fever A rash develops in around 99% of patients who take amoxicillin whilst they have infectious mononucleosis. Her treatment should be supportive as detailed below. Diagnosis heterophil antibody test (Monospot test) Management is supportive and includes: rest during the early stages, drink plenty of fluid, avoid alcohol simple analgesia for any aches or pains consensus guidance in the UK is to avoid playing contact sports for 8 weeks after having glandular fever to reduce the risk of splenic rupture

Answer 3

Chickenpox is caused by primary infection with varicella zoster virus. Shingles is reactivation of dormant virus in dorsal root ganglion ``` Chickenpox is highly infectious spread via the respiratory route can be caught from someone with shingles infectivity = 4 days before rash, until 5 days after the rash first appeared* incubation period = 10-21 days ``` Clinical features (tend to be more severe in older children/adults) fever initially itchy, rash starting on head/trunk before spreading. Initially macular then papular then vesicular systemic upset is usually mild

Answer 4

Management is supportive keep cool, trim nails calamine lotion school exclusion: current HPA advice is 5 days from start of skin eruption. They also state 'Traditionally children have been excluded until all lesions are crusted. However, transmission has never been reported beyond the fifth day of the rash.' immunocompromised patients and newborns with peripartum exposure should receive varicella zoster immunoglobulin (VZIG). If chickenpox develops then IV aciclovir should be considered. This patient is immunocompromised secondary to the chemotherapy and is therefore at risk of a severe varicella infection. She should therefore be given varicella zoster immunoglobulin. A common complication is secondary bacterial infection of the lesions. Rare complications include: pneumonia encephalitis (cerebellar involvement may be seen) disseminated haemorrhagic chickenpox arthritis, nephritis and pancreatitis may very rarely be seen *it was traditionally taught that patients were infective until all lesions had scabbed over

Answer 5

Necrotising fasciitis is a medical emergency that is difficult to recognise in the early stages It can be classified according to the causative organism: type 1 is caused by mixed anaerobes and aerobes (often occurs post-surgery in diabetics) type 2 is caused by Streptococcus pyogenes Features acute onset painful, erythematous lesion develops extremely tender over infected tissue Management urgent surgical referral debridement to get rid of necrotic tissue. otherwise rapidly fatal. intravenous antibiotics - benzylpen (covers group a strep) + ciproflox (covers gram neg) + clindamycin (covers both and high tissue penetration and as inhibits protein synth helps switch off toxin production) key features - disproportionately sick and pain compared to apparent skin look severity.

Answer 6

Management benzylpenicillin alternatives: doxycycline in those allergic to penicillin the Jarisch-Herxheimer reaction is sometimes seen following treatment. Fever, rash, tachycardia after first dose of antibiotic. It is thought to be due to the release of endotoxins following bacterial death and typically occurs within a few hours of treatment.

Answer 7

Systemic inflammatory response syndrome (SIRS) at least 2 of the following: body temperature less than 36°C or greater than 38.3°C heart rate greater than 90/min respiratory rate greater than 20 breaths per minute blood glucose > 7.7mmol/L in the absence of known diabetes white cell count less than 4 or greater than 12 SIRS may occur as a result of an infection (bacterial, viral or fungal) or in response to a non-infective inflammatory cause, for example burns or pancreatitis. Sepsis is defined as SIRS in response to a proven or presumed infection. The mortality rate of sepsis is around 10%.

Answer 8

Recently the Sepsis Trust have introduced the concept of 'red flag' sepsis. They recommend starting the 'sepsis six' if any 1 of the following are present: ``` Red flag signs: systolic blood pressure 40mmHg fall from baseline mean arterial pressure 131 per minute respiratory rate > 25 per minute* AVPU = V, P or U* ``` They also detail a number of laboratory findings which indicate severe sepsis. Severe sepsis sepsis with end organ dysfunction or hypoperfusion (indicated by hypotension, lactic acidosis or decreased urine output or others) Septic shock severe sepsis with persistently low blood pressure which has failed to respond to the administration of intravenous fluids.

Answer 9

Management Clearly the underlying cause of the patients sepsis needs to be identified and treated and the patient supported regardless of the cause or severity. If however any of the red flags are present the 'sepsis six' should be started straight away: 1. Administer high flow oxygen. 2. Take blood cultures 3. Give broad spectrum antibiotics 4. Give intravenous fluid challenges 5. Measure serum lactate and haemoglobin 6. Measure accurate hourly urine output

Answer 10

``` Investigations suggested by NICE full blood count CRP coagulation screen blood culture whole-blood PCR blood glucose blood gas ``` Lumbar puncture if no signs of raised intracranial pressure Management All patients should be transferred to hospital urgently. If patients are in a pre-hospital setting (for example a GP surgery) and meningococcal disease is suspected then intramuscular benzylpenicillin may be given, as long as this doesn't delay transit to hospital. just a holding measure. BNF recommendations on antibiotics: interchange cefotaxime with ceftriaxone as that is what med school says. Initial empirical therapy aged 50 years Intravenous cefotaxime + amoxicillin Meningococcal meningitis Intravenous benzylpenicillin or cefotaxime Pneuomococcal meningitis Intravenous cefotaxime add in dexamethasone Meningitis caused by Haemophilus influenzae Intravenous cefotaxime Meningitis caused by Listeria Intravenous amoxicillin + gentamicin If the patient has a history of immediate hypersensitivity reaction to penicillin or to cephalosporins the BNF recommends using chloramphenicol.

Answer 11

There are around 1,500-2,000 cases each year of malaria in patients returning from endemic countries. The majority of these cases (around 75%) are caused by the potentially fatal Plasmodium falciparum protozoa. The majority of patients who develop malaria did not take prophylaxis. It should also be remembered that UK citizens who originate from malaria endemic areas quickly lose their innate immunity. Up-to-date charts with recommended regimes for malarial zones should be consulted prior to prescribing one example is malarone: Atovaquone + proguanil (Malarone) GI upset, take 1 - 2 days before travel, end 7 days after return

Answer 12

Hand, foot and mouth disease is a self-limiting condition affecting children. It is caused by the intestinal viruses of the Picornaviridae family (most commonly coxsackie A16 and enterovirus 71). It is very contagious and typically occurs in outbreaks at nursery Clinical features mild systemic upset: sore throat, fever oral ulcers followed later by vesicles on the palms and soles of the feet Management general advice about hydration and analgesia reassurance no link to disease in cattle children do not need to be excluded from school* *The HPA recommends that children who are unwell should be kept off school until they feel better. They also advise that you contact them if you suspect that there may be a large outbreak.

Answer 13

Start anti-retrovirals in HIV when CD4

Answer 14

Whilst the organism Pneumocystis carinii is now referred to as Pneumocystis jiroveci, the term Pneumocystis carinii pneumonia (PCP) is still in common use Pneumocystis jiroveci is an unicellular eukaryote, generally classified as a fungus but some authorities consider it a protozoa PCP is the most common opportunistic infection in AIDS all patients with a CD4 count

Answer 15

Investigation CXR: typically shows bilateral interstitial pulmonary infiltrates but can present with other x-ray findings e.g. lobar consolidation. May be normal exercise-induced desaturation sputum often fails to show PCP, bronchoalveolar lavage (BAL) often needed to demonstrate PCP (silver stain shows characteristic cysts) Management co-trimoxazole IV pentamidine in severe cases steroids if hypoxic (if pO2

Answer 16

The most common cause of non-falciparum malaria is Plasmodium vivax, with Plasmodium ovale and Plasmodium malariae accounting for the other cases. Plasmodium vivax is often found in Central America and the Indian Subcontinent whilst Plasmodium ovale typically comes from Africa Features general features of malaria: fever, headache, splenomegaly Plasmodium vivax/ovale: cyclical fever every 48 hours. Plasmodium malariae: cyclical fever every 72 hours Plasmodium malariae: is associated with nephrotic syndrome Ovale and vivax malaria have a hypnozoite stage and may therefore relapse following treatment. Treatment non-falciparum malarias are almost always chloroquine sensitive patients with ovale or vivax malaria should be given primaquine following acute treatment with chloroquine to destroy liver hypnozoites and prevent relapse

Answer 17

Genital warts (also known as condylomata accuminata) are a common cause of attendance at genitourinary clinics. They are caused by the many varieties of the human papilloma virus HPV, especially types 6 & 11. It is now well established that HPV (primarily types 16,18 & 33) predisposes to cervical cancer. Features small (2 - 5 mm) fleshy protuberances which are slightly pigmented may bleed or itch Management topical podophyllum or cryotherapy are commonly used as first-line treatments depending on the location and type of lesion. Multiple, non-keratinised warts are generally best treated with topical agents whereas solitary, keratinised warts respond better to cryotherapy imiquimod is a topical cream which is generally used second line genital warts are often resistant to treatment and recurrence is common although the majority of anogenital infections with HPV clear without intervention within 1-2 years

Answer 18

Leptospirosis Also known as Weil's disease*, leptospirosis is commonly seen in questions referring to sewage workers, farmers, vets or people who work in abattoir. It is caused by the spirochaete Leptospira interrogans (serogroup L icterohaemorrhagiae), classically being spread by contact with infected rat urine. Weil's disease should always be considered in high-risk patients with hepatorenal failure ``` Features fever flu-like symptoms renal failure (seen in 50% of patients) jaundice subconjunctival haemorrhage headache, may herald the onset of meningitis ``` Management high-dose benzylpenicillin or doxycycline *the term Weil's disease is sometimes reserved for the most severe 10% of cases that are associated with jaundice

Answer 19

An aspergilloma is a mycetoma (mass-like fungus ball) which often colonises an existing lung cavity (e.g. secondary to tuberculosis, lung cancer or cystic fibrosis) Usually asymptomatic but features may include cough haemoptysis (may be severe) Investigations chest x-ray containing a rounded opacity high titres Aspergillus precipitins

Answer 20

Gonorrhoea is caused by the Gram negative diplococcus Neisseria gonorrhoea. Acute infection can occur on any mucous membrane surface, typically genitourinary but also rectum and pharynx. The incubation period of gonorrhoea is 2-5 days Features males: urethral discharge, dysuria females: cervicitis e.g. leading to vaginal discharge rectal and pharyngeal infection is usually asymptomatic Local complications that may develop include urethral strictures, epididymitis and salpingitis (hence may lead to infertility). Disseminated infection may occur Management 1 - ceftriaxone 500 mg intramuscularly as a single dose with azithromycin 1 g oral as a single dose. The azithromycin is thought to act synergistically with ceftriaxone and is also useful for eradicating any co-existent Chlamydia infections

Answer 21

Mycoplasma pneumoniae is a cause of atypical pneumonia which often affects younger patients. It is associated with a number of characteristic complications such as erythema multiforme and cold autoimmune haemolytic anaemia. Epidemics of Mycoplasma pneumoniae classically occur every 4 years. It is important to recognise atypical pneumonias as they may not respond to penicillins or cephalosporins due to it lacking a peptidoglycan cell wall. Features the disease typically has a prolonged and gradual onset flu-like symptoms classically precede a dry cough bilateral consolidation on x-ray complications may occur as below Complications cold agglutins (IgM) may cause an haemolytic anaemia, thrombocytopenia erythema multiforme, erythema nodosum meningoencephalitis, Guillain-Barre syndrome bullous myringitis: painful vesicles on the tympanic membrane pericarditis/myocarditis gastrointestinal: hepatitis, pancreatitis renal: acute glomerulonephritis Investigations diagnosis is generally by Mycoplasma serology positive cold agglutination test Management erythromycin/clarithromycin tetracyclines such as doxycycline are an alternative

Answer 22

Syphilis is a sexually transmitted infection caused by the spirochaete Treponema pallidum. Infection is characterised by primary, secondary and tertiary stages. A painless ulcer (chancre) is seen in the primary stage. The incubation period= 9-90 days Syphilis is a sexually transmitted infection caused by the spirochaete Treponema pallidum. Infection is characterised by primary, secondary and tertiary stages. The incubation period is between 9-90 days Primary features chancre - painless ulcer at the site of sexual contact local non-tender lymphadenopathy often not seen in women (the lesion may be on the cervix) Secondary features - occurs 6-10 weeks after primary infection systemic symptoms: fevers, lymphadenopathy rash on trunk, palms and soles buccal 'snail track' ulcers (30%) condylomata lata ``` Tertiary features gummas aortic aneurysms general paralysis of the insane tabes dorsalis ``` ``` Features of congenital syphilis blunted upper incisor teeth keratitis saber shins saddle nose deafness ```

Answer 23

Chancroid is a tropical disease caused by Haemophilus ducreyi. It causes painful genital ulcers associated with unilateral, painful inguinal lymph node enlargement. The ulcers typically have a sharply defined, ragged, undermined border.

Answer 24

Lymphogranuloma venereum (LGV) is caused by Chlamydia trachomatis. Typically infection comprises of three stages stage 1: small painless pustule which later forms an ulcer stage 2: painful inguinal lymphadenopathy stage 3: proctocolitis LGV is treated using doxycycline.

Answer 25

genital herpes syphillis chancroid Lymphogranuloma venereum Other causes of genital ulcers Behcet's disease carcinoma granuloma inguinale: Klebsiella granulomatis* *previously called Calymmatobacterium granulomatis

Answer 26

Hepatitis A | Human Normal Immunoglobulin (HNIG) or hepatitis A vaccine may be used depending on the clinical situation

Answer 27

Hepatitis B HBsAg positive source: if the person exposed is a known responder to HBV vaccine then a booster dose should be given. If they are in the process of being vaccinated or are a non-responder they need to have hepatitis B immune globulin (HBIG) and the vaccine unknown source: for known responders the green book advises considering a booster dose of HBV vaccine. For known non-responders HBIG + vaccine should be given whilst those in the process of being vaccinated should have an accelerated course of HBV vaccine 20-30% conversion rate

Answer 28

Hepatitis C monthly PCR - if seroconversion then interferon +/- ribavirin 0.5-2% conversion rate

Answer 29

HIV a combination of oral antiretrovirals (e.g. Tenofovir, emtricitabine, lopinavir and ritonavir) as soon as possible (i.e. Within 1-2 hours, but may be started up to 72 hours following exposure) for 4 weeks serological testing at 12 weeks following completion of post-exposure prophylaxis reduces risk of transmission by 80% 0.3% conversion rate in needlestick

Answer 30

Varicella zoster | VZIG for IgG negative pregnant women/immunosuppressed

Answer 31

Early features erythema chronicum migrans (small papule often at site of the tick bite which develops into a larger annular lesion with central clearing, 'bulls-eye'. Oc curs in 70% of patients) systemic symptoms: malaise, fever, arthralgia Later features CVS: heart block, myocarditis neurological: cranial nerve palsies, meningitis polyarthritis

Answer 32

Exacerbations of chronic bronchitis Amoxicillin or tetracycline or clarithromycin Uncomplicated community-acquired pneumonia Amoxicillin (Doxycycline or clarithromycin in penicillin allergic, add flucloxacillin if staphylococci suspected e.g. In influenza) severe CAP - (IV) Co-amoxiclav or 2nd/3rd gen. cephalosporin + Macrolide Pneumonia possibly caused by atypical pathogens Clarithromycin Hospital-acquired pneumonia: Within 5 days of admission: co-amoxiclav or cefuroxime More than 5 days after admission: piperacillin with tazobactam OR a broad-spectrum cephalosporin (e.g. ceftazidime) OR a quinolone (e.g. ciprofloxacin)

Answer 33

Legionnaire's disease is caused by the intracellular bacterium Legionella pneumophilia. It is typically colonizes water tanks and hence questions may hint at air-conditioning systems or foreign holidays. Person-to-person transmission is not seen ``` Features flu-like symptoms including fever (present in > 95% of patients) dry cough relative bradycardia confusion lymphopaenia hyponatraemia deranged liver function tests pleural effusion: seen in around 30% of ptients ``` Diagnosis urinary antigen Management treat with erythromycin

Answer 34

Investigation serology: antibodies to Borrelia burgdorferi Management doxycycline if early disease. Amoxicillin is an alternative if doxycycline is contraindicated (e.g. pregnancy) ceftriaxone if disseminated disease Jarisch-Herxheimer reaction is sometimes seen after initiating therapy: fever, rash, tachycardia after first dose of antibiotic (more commonly seen in syphilis, another spirochaetal disease)

Answer 35

Clostridium difficile is a Gram positive rod often encountered in hospital practice. It produces an exotoxin which causes intestinal damage leading to a syndrome called pseudomembranous colitis. Clostridium difficile develops when the normal gut flora are suppressed by broad-spectrum antibiotics. Clindamycin is historically associated with causing Clostridium difficile but the aetiology has evolved significantly over the past 10 years. Second and third generation cephalosporins are now the leading cause of Clostridium difficile. ``` Features diarrhoea abdominal pain a raised white blood cell count is characteristic if severe toxic megacolon may develop ``` Diagnosis is made by detecting Clostridium difficile toxin (CDT) in the stool Management first-line therapy is oral metronidazole for 10-14 days if severe or not responding to metronidazole then oral vancomycin may be used for life-threatening infections a combination of oral vancomycin and intravenous metronidazole should be used

Answer 36

Escherichia coli is a facultative anaerobic, lactose-fermenting, Gram negative rod which is a normal gut commensal. E. coli infections lead to a variety of diseases in humans including: diarrhoeal illnesses UTIs neonatal meningitis Serotypes E. coli may be classified according to the antigens which may trigger an immune response: O, K and H. E. coli O157:H7 is a particular strain associated with severe, haemorrhagic, watery diarrhoea. It has a high mortality rate and can be complicated by haemolytic uraemic syndrome. It is often spread by contaminated ground beef.

Answer 37

Travellers' diarrhoea may be defined as at least 3 loose to watery stools in 24 hours with or without one of more of abdominal cramps, fever, nausea, vomiting or blood in the stool. The most common cause is Escherichia coli

Answer 38

Another pattern of illness is 'acute food poisoning'. This describes the sudden onset of nausea, vomiting and diarrhoea after the ingestion of a toxin. Acute food poisoning is typically caused by Staphylococcus aureus, Bacillus cereus or Clostridium perfringens.

Answer 39

Seasonal influenza still accounts for a significant morbidity and mortality in the UK each winter, with the influenza season typically starting in the middle of November. This may vary year from year so it is recommended that vaccination occurs between September and early November. There are three types of influenza virus; A, B and C. Types A and B account for the majority of clinical disease. Prior to 2013 flu vaccination was only offered to the elderly and at risk groups. Remember that the type of vaccine given routinely to children and the one given to the elderly and at risk groups is different (live vs. inactivated) - this explains the different contraindications Children A new NHS influenza vaccination programme for children was announced in 2013. There are three key things to remember about the children's vaccine: it is given intranasally the first dose is given at 2-3 years, then annually after that it is a live vaccine (cf. injectable vaccine below)

Answer 40

The Mantoux test is the main technique used to screen for latent tuberculosis. In recent years the interferon-gamma blood test has also been introduced. It is used in a number of specific situations such as: the Mantoux test is positive or equivocal people where a tuberculin test may be falsely negative (see below) Mantoux test 0.1 ml of 1:1,000 purified protein derivative (PPD) injected intradermally result read 2-3 days later, the larger the swelling the greater the reactivity. 6-15 mm suggests immune, over 15 suggests current infection. Heaf test The Heaf test was previously used in the UK but has been since been discontinued. It involved injection of PPD equivalent to 100,000 units per ml to the skin over the flexor surface of the left forearm. It was then read 3-10 days later.

Answer 41

The low platelet count and raised transaminase level is typical of dengue fever Dengue fever Dengue fever is a viral infection which can progress to viral haemorrhagic fever (also yellow fever, Lassa fever, Ebola) Basics transmitted by the Aedes aegyti mosquito incubation period of 7 days a form of disseminated intravascular coagulation (DIC) known as dengue haemorrhagic fever (DHF) may develop. Around 20-30% of these patients go on to develop dengue shock syndrome (DSS) ``` Features causes headache (often retro-orbital) fever myalgia pleuritic pain facial flushing (dengue) maculopapular rash ``` Treatment is entirely symptomatic e.g. fluid resuscitation, blood transfusion etc

Answer 42

Types 6 and 11 are responsible for 90% of genital warts cases Genital warts Genital warts (also known as condylomata accuminata) are a common cause of attendance at genitourinary clinics. They are caused by the many varieties of the human papilloma virus HPV, especially types 6 & 11. It is now well established that HPV (primarily types 16,18 & 33) predisposes to cervical cancer. Features small (2 - 5 mm) fleshy protuberances which are slightly pigmented may bleed or itch Management topical podophyllum or cryotherapy are commonly used as first-line treatments depending on the location and type of lesion. Multiple, non-keratinised warts are generally best treated with topical agents whereas solitary, keratinised warts respond better to cryotherapy imiquimod is a topical cream which is generally used second line genital warts are often resistant to treatment and recurrence is common although the majority of anogenital infections with HPV clear without intervention within 1-2 years

Answer 43

Kaposi's sarcoma caused by HHV-8 (human herpes virus 8) presents as purple papules or plaques on the skin or mucosa (e.g. gastrointestinal and respiratory tract) skin lesions may later ulcerate respiratory involvement may cause massive haemoptysis and pleural effusion radiotherapy + resection

Answer 44

Focal neurological lesions Toxoplasmosis accounts for around 50% of cerebral lesions in patients with HIV constitutional symptoms, headache, confusion, drowsiness CT: usually single or multiple ring enhancing lesions, mass effect may be seen management: sulfadiazine and pyrimethamine Primary CNS lymphoma accounts for around 30% of cerebral lesions associated with the Epstein-Barr virus CT: single or multiple homogenous enhancing lesions treatment generally involves steroids (may significantly reduce tumour size), chemotherapy (e.g. methotrexate) + with or without whole brain irradiation. Surgical may be considered for lower grade tumours Differentiating between toxoplasmosis and lymphoma is a common clinical scenario in HIV patients. It is clearly important given the vastly different treatment strategies. The table below gives some general differences. Please see the Radiopaedia link for more details. toxo overview - Multiple lesions Ring or nodular enhancement Thallium SPECT negative lymphoma overview - Single lesion Solid (homogenous) enhancement Thallium SPECT positive Tuberculosis much less common than toxoplasmosis or primary CNS lymphoma CT: single enhancing lesion

Answer 45

Encephalitis may be due to CMV or HIV itself HSV encephalitis but is relatively rare in the context of HIV CT: oedematous brain Cryptococcus most common fungal infection of CNS headache, fever, malaise, nausea/vomiting, seizures, focal neurological deficit CSF: high opening pressure, India ink test positive CT: meningeal enhancement, cerebral oedema meningitis is typical presentation but may occasionally cause a space occupying lesion Progressive multifocal leukoencephalopathy (PML) widespread demyelination due to infection of oligodendrocytes by JC virus (a polyoma DNA virus) symptoms, subacute onset : behavioural changes, speech, motor, visual impairment CT: single or multiple lesions, no mass effect, don't usually enhance. MRI is better - high-signal demyelinating white matter lesions are seen AIDS dementia complex caused by HIV virus itself symptoms: behavioural changes, motor impairment CT: cortical and subcortical atrophy

Answer 46

HIV seroconversion is symptomatic in 60-80% of patients and typically presents as a glandular fever type illness. Increased symptomatic severity is associated with poorer long term prognosis. It typically occurs 3-12 weeks after infection ``` Features sore throat lymphadenopathy malaise, myalgia, arthralgia diarrhoea maculopapular rash mouth ulcers rarely meningoencephalitis ``` Diagnosis antibodies to HIV may not be present HIV PCR and p24 antigen tests can confirm diagnosis

Answer 47

There are two strains of the herpes simplex virus (HSV) in humans: HSV-1 and HSV-2. Whilst it was previously thought HSV-1 accounted for oral lesions (cold sores) and HSV-2 for genital herpes it is now known there is considerable overlap Features primary infection: may present with a severe gingivostomatitis cold sores painful genital ulceration Management gingivostomatitis: oral aciclovir, chlorhexidine mouthwash cold sores: topical aciclovir although the evidence base for this is modest genital herpes: oral aciclovir. Some patients with frequent exacerbations may benefit from longer term aciclovir

Answer 48

Who should be screened for MRSA? all patients awaiting elective admissions (exceptions include day patients having terminations of pregnancy and ophthalmic surgery. Patients admitted to mental health trusts are also excluded) from 2011 all emergency admissions will be screened

Answer 49

nasal swab and skin lesions or wounds the swab should be wiped around the inside rim of a patient's nose for 5 seconds the microbiology form must be labelled 'MRSA screen'

Answer 50

nose: mupirocin 2% in white soft paraffin, tds for 5 days skin: chlorhexidine gluconate, od for 5 days. Apply all over but particularly to the axilla, groin and perineum

Answer 51

vancomycin teicoplanin linezolid - very narrow spectrum. high conc in tears and sweat. causes blood dycrasias and optic neuropathy (irreversible), can turn tongue black. can also mimic MAOI so risk of serotonin syndrome in SSRIs.

Answer 52

Campylobacter Campylobacter is the commonest bacterial cause of infectious intestinal disease in the UK. The majority of cases are caused by the Gram-negative bacillus Campylobacter jejuni. It is spread by the faecal-oral route and has an incubation period of 1-6 days. Features prodrome: headache malaise diarrhoea: often bloody abdominal pain Management usually self-limiting the BNF advises treatment if severe or the patient is immunocompromised. Clinical Knowledge summaries also recommend antibiotics if severe symptoms (high fever, bloody diarrhoea, or more than eight stools per day) or symptoms have last more than one week the first-line antibiotic is clarithromycin, another source says ciprofloxacin though Complications Guillain-Barre syndrome may follow Campylobacter jejuni infections Reiter's syndrome septicaemia, endocarditis, arthritis

Answer 53

Leishmaniasis is caused by the intracellular protozoa Leishmania, usually being spread by sand flies. Cutaneous, mucocutaneous leishmaniasis and visceral forms are seen Cutaneous leishmaniasis caused by Leishmania tropica or Leishmania mexicana crusted lesion at site of bite may be underlying ulcer Mucocutaneous leishmaniasis caused by Leishmania braziliensis skin lesions may spread to involve mucosae of nose, pharynx etc ``` Visceral leishmaniasis (kala-azar) mostly caused by Leishmania donovani occurs in the Mediterranean, Asia, South America, Africa fever, sweats, rigors massive splenomegaly. hepatomegaly poor appetite*, weight loss grey skin - 'kala-azar' means black sickness pancytopaenia secondary to hypersplenism ``` *occasionally patients may report increased appetite with paradoxical weight loss

Answer 54

Staphylococci are a common type of bacteria which are often found normal commensal organisms but may also cause invasive disease. Some basic facts include: Gram-positive cocci facultative anaerobes produce catalase The two main types of Staphylococci you need to know about are Staphylococcus aureus and Staphylococcus epidermidis. staph aureus = • Coagulase-positive • Causes skin infections (e.g. cellulitis), abscesses, osteomyelitis, toxic shock syndrome staph epidermidis = • Coagulase-negative • Cause of central line infections and infective endocarditis. typically a contaminant in a culture but is problematic in long term lines or prosthetic materials.

Answer 55

Community acquired pneumonia (CAP) may be caused by the following infectious agents: Streptococcus pneumoniae (accounts for around 80% of cases) Haemophilus influenzae Staphylococcus aureus: commonly after the 'flu atypical pneumonias (e.g. Due to Mycoplasma pneumoniae) viruses Klebsiella pneumoniae is classically in alcoholics

Answer 56

CURB-65 criteria of severe pneumonia Confusion (abbreviated mental test score 7 mmol/L Respiratory rate >= 30 / min BP: systolic = 65 years Patients with 3 or more (out of 5) of the above criteria are regarded as having a severe pneumonia Patients with a CURB-65 score of 0 should be managed in the community. Patients with a CURB-65 score of 1 should have their Sa02 assessed which should be >92% to be safely managed in the community and a CXR performed. If the CXR shows bilateral/multilobar shadowing hospital admission is advised. Patients with a CURB-65 score of 2 or more should be managed in hospital as this represents a severe community acquired pneumonia. The CURB-65 score also correlates with an increased risk of mortality at 30 days with patients with a CURB-65 score of 4 approaching a 30% mortality rate at 30 days. Other factors associated with a poor prognosis include: presence of coexisting disease hypoxaemia (pO2

Answer 57

``` acute otitis media: 4 days acute sore throat/acute pharyngitis/acute tonsillitis: 1 week common cold: 1 1/2 weeks acute rhinosinusitis: 2 1/2 weeks acute cough/acute bronchitis: 3 weeks ```

Answer 58

A no antibiotic prescribing or delayed antibiotic prescribing approach is generally recommended for patients with acute otitis media, acute sore throat/acute pharyngitis/acute tonsillitis, common cold, acute rhinosinusitis or acute cough/acute bronchitis. However, an immediate antibiotic prescribing approach may be considered for: children younger than 2 years with bilateral acute otitis media children with otorrhoea who have acute otitis media patients with acute sore throat/acute pharyngitis/acute tonsillitis when 3 or more Centor criteria are present ``` The Centor criteria* are as follows: presence of tonsillar exudate tender anterior cervical lymphadenopathy or lymphadenitis history of fever absence of cough ``` If the patient is deemed at risk of developing complications, an immediate antibiotic prescribing policy is recommended

Answer 59

Strongyloides stercoralis is a human parasitic nematode worm. The larvae are present in soil and gain access to the body by penetrating the skin. Infection with Strongyloides stercoralis causes strongyloidiasis. Features diarrhoea abdominal pain papulovesicular lesions where the skin has been penetrated by infective larvae e.g. soles of feet and buttocks larva currens: pruritic, linear, urticarial rash if the larvae migrate to the lungs a pneumonitis similar to Loeffler's syndrome may be triggered Treatment ivermectin and albendazole are used

Answer 60

Head lice (also known as pediculosis capitis or 'nits') is a common condition in children caused by the parasitic insect Pediculus capitis, which lives on and among the hair of the scalp of humans Diagnosis fine-toothed combing of wet or dry hair Management treatment is only if living lice are found a choice of treatments should be offered - malathion, wet combing, dimeticone, isopropyl myristate and cyclomethicone School exclusion is not advised for children with head lice

Answer 61

Remember: Gram positive cocci = staphylococci + streptococci (including enterococci) Gram negative cocci = Neisseria meningitidis + Neisseria gonorrhoeae, also Moraxella ``` Therefore, only a small list of Gram positive rods (bacilli) need to be memorised to categorise all bacteria - mnemonic = ABCD L Actinomyces Bacillus anthracis (anthrax) Clostridium Diphtheria: Corynebacterium diphtheriae Listeria monocytogenes ``` Remaining organisms are Gram negative rods

Answer 62

``` Acute encephalitis Acute infectious hepatitis Acute meningitis Acute poliomyelitis Anthrax Botulism Brucellosis Cholera Diphtheria Enteric fever (typhoid or paratyphoid fever) Food poisoning Haemolytic uraemic syndrome (HUS) Infectious bloody diarrhoea Invasive group A streptococcal disease Legionnaires Disease Leprosy Malaria Measles Meningococcal septicaemia Mumps Plague Rabies Rubella SARS Scarlet fever Smallpox Tetanus Tuberculosis Typhus Viral haemorrhagic fever (VHF) Whooping cough Yellow fever ```

Answer 63

asymptomatic in around 70% of women and 50% of men

Answer 64

Features target lesions initially seen on the back of the hands / feet before spreading to the torso upper limbs are more commonly affected than the lower limbs pruritus is occasionally seen and is usually mild If symptoms are severe and involve blistering and mucosal involvement the term Stevens-Johnson syndrome is used. Causes viruses: herpes simplex virus (the most common cause), Orf* idiopathic bacteria: Mycoplasma, Streptococcus drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine connective tissue disease e.g. Systemic lupus erythematosus sarcoidosis malignancy

Answer 65

Giardiasis is caused by the flagellate protozoan Giardia lamblia. It is spread by the faeco-oral route Features often asymptomatic lethargy, bloating, abdominal pain non-bloody diarrhoea chronic diarrhoea, malabsorption and lactose intolerance can occur stool microscopy for trophozoite and cysts are classically negative, therefore duodenal fluid aspirates or 'string tests' (fluid absorbed onto swallowed string) are sometimes needed Treatment is with metronidazole

Answer 66

Lower urinary tract infection - Trimethoprim (unless pregnant) or Amoxicillin (most e. coli now resistant by making beta lactamase, use in pregnancy first though then check to see if effective) / Nitrofurantoin /Ciprofloxacin. A 3-day course is usually sufficient. Severe (IV) Co-amoxiclav or 2nd/3rd gen. cephalosporin ± gentamicin Acute pyelonephritis Broad-spectrum cephalosporin or quinolone. cefuroxime, or ciprofloxacin if pen allergic. Acute prostatitis Quinolone or trimethoprim

Answer 67

Clostridium difficile First episode: metronidazole Second or subsequent episode of infection: vancomycin Campylobacter enteritis Clarithromycin Salmonella (non-typhoid) Ciprofloxacin Shigellosis Ciprofloxacin

Answer 68

The tetanus vaccine is a cell-free purified toxin that is normally given as part of a combined vaccine. ``` Tetanus vaccine is currently given in the UK as part of the routine immunisation schedule at: 2 months 3 months 4 months 3-5 years 13-18 years ``` This therefore provides 5 doses of tetanus-containing vaccine. Five doses is now considered to provide adequate long-term protection against tetanus. Intramuscular human tetanus immunoglobulin should be given to patients with high-risk wounds (e.g. Compound fractures, delayed surgical intervention, significant degree of devitalised tissue) irrespective of whether 5 doses of tetanus vaccine have previously been given If vaccination history is incomplete or unknown then a dose of tetanus vaccine should be given combined with intramuscular human tetanus immunoglobulin for high-risk wounds

Answer 69

Cellulitis is a term used to describe an inflammation of the skin and subcutaneous tissues, typically due to infection by Streptococcus pyogenes or Staphylcoccus aureus. Features commonly occurs on the shins erythema, pain, swelling there may be some associated systemic upset such as fever Management The BNF recommends flucloxacillin as first-line treatment for mild/moderate cellulitis (can add penicillin V). Clarithromycin or clindamycin is recommend in patients allergic to penicillin. Many local protocols now suggest the use of oral clindamycin in patients who have failed to respond to flucloxacillin. Severe cellulitis should be treated with intravenous benzylpenicillin + flucloxacillin.

Answer 70

``` Amoxicillin • Rash with infectious mononucleosis Co-amoxiclav • Cholestasis Flucloxacillin • Cholestasis Erythromycin • Gastrointestinal upset • Prolongs QT interval ``` Ciprofloxacin • Lowers seizure threshold • Tendonitis/rupture Metronidazole • Reaction following alcohol ingestion Doxycycline • Photosensitivity Trimethoprim • Rashes, including photosensitivity • Pruritus • Suppression of haematopoiesis

Answer 71

Hospital acquired pneumonias are defined as a pneumonia occurring > 48 hours after hospital admission. They are most often caused by gram negative enterobacteria so antibiotic therapy should represent this.

Answer 72

Anaerobic organisms are often implicated in aspiration pneumonias (anaerobic organisms from the oropharynx pass into the lungs) and Metronidazole is included in most treatment regimes for this. In this question there is no mention of this patient having any risk factors for aspiration (poor swallow, oesophageal disorders, neurological disorders).

Answer 73

Remember: Gram positive cocci = staphylococci + streptococci (including enterococci) Gram negative cocci = Neisseria meningitidis + Neisseria gonorrhoeae, also Moraxella ``` Therefore, only a small list of Gram positive rods (bacilli) need to be memorised to categorise all bacteria - mnemonic = ABCD L Actinomyces Bacillus anthracis (anthrax) Clostridium Diphtheria: Corynebacterium diphtheriae Listeria monocytogenes ``` Remaining organisms are Gram negative rods

Answer 74

Croup (or laryngotracheobronchitis) is a respiratory condition that is usually triggered by an acute viral infection of the upper airway. The infection leads to swelling inside the throat, which interferes with normal breathing and produces the classical symptoms of a "barking" cough, stridor, and hoarseness. It may produce mild, moderate, or severe symptoms, which often worsen at night. It is often treated with a single dose of oral steroids; occasionally inhaled epinephrine is used in more severe cases. Hospitalization is rarely required. Croup is diagnosed on clinical grounds, once potentially more severe causes of symptoms have been excluded (i.e. epiglottitis or an airway foreign body). Further investigations—such as blood tests, X-rays, and cultures—are usually not needed. It is a relatively common condition that affects about 15% of children at some point, most commonly between 6 months and 5–6 years of age. It is almost never seen in teenagers or adults.

Answer 75

Behcet's syndrome is a complex multisystem disorder associated with presumed autoimmune mediated inflammation of the arteries and veins. The precise aetiology has yet to be elucidated however. The classic triad of symptoms are oral ulcers, genital ulcers and anterior uveitis Epidemiology more common in the eastern Mediterranean (e.g. Turkey) more common in men (complicated gender distribution which varies according to country. Overall, Behcet's is considered to be more common and more severe in men) tends to affect young adults (e.g. 20 - 40 years old) associated with HLA B5* and MICA6 allele around 30% of patients have a positive family history Features classically: 1) oral ulcers 2) genital ulcers 3) anterior uveitis thrombophlebitis arthritis neurological involvement (e.g. aseptic meningitis) GI: abdo pain, diarrhoea, colitis erythema nodosum, DVT Diagnosis no definitive test diagnosis based on clinical findings positive pathergy test is suggestive (puncture site following needle prick becomes inflamed with small pustule forming) *more specifically HLA B51, a split antigen of HLA B5

Answer 76

1 - beta-lactams - penicillin, cephalosporins 2 - glycopeptides - vancomycin, teicoplanin 3 - carbapenems - imipenem 4 - monobactams - aztreonam

Answer 77

1 - aminoglycosides - gentamycin 2 - tetracyclines - tetracycline, doxycycline 3 - macrolides - erythromycin, clarithromycin (imp for those allergic to penicillins. remember this!) 4 - some others - chloramphenicol, fusidic acid

Answer 78

1 - Quinolones - Ciprofloxacin, Ofloxacin 2 - Others - Metronidazole, Trimethoprim, Rifampicin, Sulphonamides

Answer 79

Penicillins Very useful against Gram +ve (some have additional Gram -ve cover). 4 major types 1. Basic penicillins (pneumococcus, streptococcus, meningococcus) - Benzylpenicillin (penicillin G) (must be given parenterally, infective endo carditis, celllulitis, meningococcal meningitis) - excreted v quickly. - Phenoxymethypenicillin (penicillin V) (oral but poor bioavailability, QDS which is bad for compliance, poor tissue distribution, used for Strep throat, prophylaxis in splenectomy against streps. ) only PO 2. Broad-spectrum penicillins (Gram -ve cover e.g. As above + E.coli, H. Inﬂuenzae) - Amoxicillin - 3. β-lactamase resistant peniccillins: - Flucloxacillin (for staphylococci - pproduces a beta lactase hence can't use basic penicillins. v narrow spectrum, pretty much staph only. PO for simple things in the community e.g. access. IV for infective endocarditis, osteomyelitis and septic arthritis.) - Co-amoxiclav (Augmentin). the beta lactase preferentially binds the clavulonic acid, gets saturated and lets the amox work. 4. Anti-pseudomonal penicillins - Pipericillin + Tazobactam (another beta lactamase inhibitor) = Tazocin . only available IV. v potent for gram positive and negative and pseudomonas. and ESBLs. be cautious to prevent resistance development.

Answer 80

C.I.s - Hypersensitivity Important S.E.s - Rash, Anaphylaxis, Nausea/vomiting Interactions - Reduced efficacy of COC

Answer 81

Cephalosporins There are 3 generations whose Gram -ve activity becomes greater as you ascend... Types - Drug - Indications 1st generation - Rubbish! Cefalexin is orally active - Rubbish! Used for UTIs, refractory cystitis. cefadroxil, cefixime. all 3 are oral. different trusts use different ones. pretty much only use is first line uncomplicated UTI in pregnancy over amox due to resistance emerging. 2nd generation - Cefuroxime - IV principally. does not cover pseudomonas but is otherwise broad spectrum. gram neg cover. covers quite a lot. pneumonias, UTIs. not anti anaerobes. 1st line cephalosporin for most indications. poor CNS penetration 3rd generation - - Cefotaxime - Meningitis - Ceftazidime - Anti-psudomonal. only IV. poor gram positive cover. - Ceftriaxone - Good for serious infections E.g. Pneumonia, septicaemia

Answer 82

C.I.s - Important S.E.s - Interactions Hypersensitivity (10% who are allergic to penicillin with also be allergic) SEs - C. Difficile (so sometimes not stocked except cefotaxime for meningitis)!! Bleeding, Thrombophlebitis interactions - not so much

Answer 83

3. Glycopeptides e. g. vancomycin (IE/MRSA/C. difﬁcile), teicoplanin (bad gram +ve infections) These agents are generally active against aerobic and anerobic Gram +ve. pretty narrow spectrum. only IV. oral vancomycin only for C. diff. not good against gram negative as cannot penetrate.

Answer 84

Important S.E.s - Ototoxicity, Nephrotoxicity, Thrombophlebitis Interactions - Increased risk of ototoxicity with loop diuretics. Increased risk of nephrotoxicity with cyclosporin and aminoglycosides

Answer 85

Carbapenems e.g. imipenem, meropenem, ertapenem(exception - not antipseudomonal). These agents have a very wide broad specture against Gram +ve and Gram -ve. staph, extended gram negative, anaerobe activity. drug of choice for ESBL producing drugs. v expensive. Best single choice for nosocomial infection ((of a disease) originating in a hospital) remember them for what they DON'T do. only IV. by and large don't do the problem gram positive. USE WITH CAUTION IN PENICILLIN ALLERGY AS THOUGHT TO BE SOME OVERLAP BUT CONTENTIOUS. essentially the last line drug in resistant cases.

Answer 86

Nausea/vomiting | Seizures

Answer 87

Aminoglycosides e.g. gentamicin (topicals, 2nd line in severe Gram -ve infection. v water soluble so primarily a bacteraemia drug, tissue penetration is not great. not good in lung as consolidation prevents aeration. often used as an adjunct to other antibiotics in this way. infective endocarditis. ), streptomycin (resistant TB) These are agents that inhibit protein synthesis through binding to the 30S ribosome They are inactive orally Requre therapeutic drug monitoring (measure 1 hour post-administration

Answer 88

C.I.s - Pregancy, myasthena gravis Important S.E.: - Nephrotoxicity = important, check renal function before starting and monitor. - Ototoxicity (direct damage to C VIII) - Thrombophlebitis Interactions - Loop diuretics and cyclosporin potentiate nephrotoxicity - Antagonise anitcholinesterases

Answer 89

Tetracycline - e.g. tetracycline (acne), doxycycline (chlamydia, lyme disease, anthrax) - These are relatively broad specturm agents that have particular action against intracellular organisms

Answer 90

C.I.s - Renal impairment (slight CI), may exacerbate. Important S.E. - Teeth discolouration/bone deposits(do not use Deposited in bone and teeth  grey staining Avoid in pregnancy and breast feeding and children

Answer 91

Macrolides act on the ribosome. pretty narrow spectrum, no real gram negative cover. largely bacteriostatic so need host immune system to finish bacteria off. e. g. erythromycin (good respiratory antibiotics, useful in penicillin-allergic), clarithromycin (more potent). bad IV thrombophlebitis. not good brain penetration. alternative to staph and strep. drug of choice for atypicals. - first drugs to think of if you're thinking of a penicillin but the patient is penicillin allergic. These drugs do not cross the blood-brain barrier so not useful in meningitis Erythromycin is not known to be harmful in pregnancy Clarithromycin has useful activity against haemophilus azithromycin - chlamydia trachomatus.

Answer 92

Important S.E. - Nausea/vomiting - Cholestatic jaundice Interactions - CP450 inhibitor - Stop statins

Answer 93

Quinolones work on DNA gyrase e.g. ciproﬂoxacin, oﬂoxacin These drugs are active against many Gram -ve and Gram +ve organisms - staph not strep, all gram neg inc pseudomonas (the only non beta lactam antipseudomonal), but not anaerobe. good intracellular, decent CNS penetration. misuse so now related to C. diff not licensed in pregnancy and children but has been used in them, no reports of issues in children e.g. in cystic fibrosis. good for 'all the dangly bits' epididmitis, prostatitis. don't give for pneumonia as not strep. newer quinolones do work against pneumococcus. levofloxacin and moxifloxacin.

Answer 94

C.I.s - Epilepsy (lower seizure threshold) - History of tendon damage Important S.E.s - GI disurbance - Tendon damage Interactions - CP450 inhibitor

Answer 95

Metronidazole This agents is very active against anaerobes and protozoal infections (entamoeba histolytics, giardia lamblia, trichomonas) It is a well tolerated drug•It requires monitoring if used > 10 days

Answer 96

C.I.s - Hepatic impairement - History of tendon damage Important S.E.s - GI disturbance - Antabuse reaction with alcohol Interactions - Increases phenytoin levels - Increases warfarin levels

Answer 97

RIPE Drug - Indications - Problems Rifampicin - Tuberculosis Leprosy - Contact prophylaxis in meningitis - Deranged LFTs, Orange secretions, CP450 inducer Isoniazed - Tuberculosis - Peripheral neuropathy (Rx - pyridoxine - Pyridoxine is one form of vitamin B6.), Hepatotoxicity Pyrazinamide - Tuberculosis, Hepatocellular toxicity Ethambutol - Tuberculosis (if isoniazid resistance is likley), Retrobulbar neuritis(

Answer 98

``` Community acquired: Tends to be - Streptoccoccus/haemophilus - Mycoplasma - Atypicals (legionella, chlamydia, PCP ``` use the CURB score to grade severity. MILD - Amoxicillin po + erythromycin po. amox covers the typicals such as strep, and erythromycin to cover the atypicals SEVERE -IV therapy - Co-amoxiclav/cefuroxime + erythromycin Atypicals - clarithryomycin, co-tromoxazole (PCP)

Answer 99

tend to be more serious and selective gram positives and negatives so need broader coverage than CAP. Aminoglycoside IV + 3rd gen. cephalosproin hospitals have their own very specific guidelines though so always check those in this instance.

Answer 100

Cefuoxime IV + metronidazole IV (metro covers the anaerobes)

Answer 101

Rifampicin Isoniazid Pyrazinamide Ethambutol+ pyridoxine (to prevent isoniazid neuropathy)

Answer 102

Take blood cultures | Anti-psudomonal penicillin IV + cefuroxime IV

Answer 103

Take blood cultures Piperacillin IV + Gentamicin IV most common infection source is endogenous from their own gut. high rate of ESBL hence tazocin. can rationalise later. if no response within 48 hours consider: 1 - escalating tazocin to meropenem 2 - then add teicoplanin for better staph cover, check any central lines. MRSA and CNS is the worry. 3 - adding in anti-fungal. unusual post solid tumour chemo but more common in haematological cancers.

Answer 104

Urine MC & S = Microscopy, Culture and Sensitivities MILD - Trimethoprim (or amoxicillin in pregnancy (although 50% will be resistant)) SEVERE - Co-amoxiclav. most caused by UTi.

Answer 105

``` Based up +ve swab result Vancomycin po(teicoplanin) ``` VRSA not yet found in the uk

Answer 106

Often following cephalosporin treatment Metranidazole po Vancomycin po

Answer 107

Usually staph. and/or strep. need to cover both. Benzylpenicillin - covers strep Flucloxacillin - covers staph

Answer 108

To cover anaerobes Metronidazole IV Cefuroxime IV both, together.

Answer 109

The case vignette describes a typical presentation of measles. Measles is one of the most highly infectious illnesses caused by an RNA paramyxovirus. Patients typically present with a prodrome of non-specific cold-like symptoms such as coryza, cough, fever and conjunctivits. These symptoms are usually present for one week prior to the development of the rash. The rash itself is erythematous and maculopapular. It typically starts from behind the ears and spreads down the trunk and the rest of the body. The grey/white spots described are 'Koplik spots'. These appear on mucous membrane of the mouth 2-3 days before the rash appears and may be present for a further couple of days afterwards. They are pathognomonic for measles. The treatment for measles is conservative with symptom management. Often patients can be managed at home, but in severe cases or if there are any complications, hospital admission is required. Children remain infectious until five days after the rash appeared. Following an episode of measles, the child is then immune to it.

Answer 110

surprisingly in a cochrane review it appeared that oral antibiotics were more effective than IV for moderate and severe cellulitis.

Answer 111

``` Pneumococcus (Strep. pneumoniae) Haemophilus influenzae Moraxella catarrhalis viral ``` Amoxicillin Or Clarithromycin Or Tetracycline

Answer 112

Viruses Rotavirus, norwalk virus Adenovirus, HIV, HSV ``` bacteria E. coli Salmonella Campylobacter Shigella Staph. aureus CLOSTRIDIUM DIFFICILE ``` protozoa Amoebic dysentery Giardia Cryptosporidia

Answer 113

Staph. aureus (wounds) Mixed faecal flora including anaerobes 2nd/3rd gen. cephalosporin + metronidazole or Co-amoxiclav alone

Answer 114

Bacterial dihydrofolate reductase inhibitor Broad spectrum, some resistance Well tolerated Excreted in urine Avoid in pregnancy (1st trimester), give amoxicillin instead (50% of the E. coli responsible for most UTI will be resistant so then culture the urine to see if cleared) Useful for empirical treatment of UTI and respiratory infections

Answer 115

``` Idiopathic/unknown - 17-60% Sarcoidosis 15-30% Streptococcal infection (URTI) - 10-50% Tuberculosis 5-10% Infections other than TB or strep¶ Pregnancy or oral contraceptives 10% Drugs other than OCAs Inflammatory bowel disease Behcet's disease ``` Erythema nodosum (EN) is characterized by red or violet subcutaneous nodules that usually develop in a pretibial location. EN is presumed to represent a delayed hypersensitivity reaction to antigens associated with the various infectious agents, drugs, and other diseases with which it is associated, although the pathogenesis is largely unclear. EN occurs in a variety of disorders for which the etiology remains unknown; for example, sarcoidosis, inflammatory bowel disease, and Behçet’s disease.

Answer 116

is a sign of appendicitis. If palpation of the left lower quadrant of a person's abdomen increases the pain felt in the right lower quadrant, the patient is said to have a positive Rovsing's sign and may have appendicitis.

Answer 117

can genotype for resistance genes to some medicaions. for example the resistance gene for rifampicin is 95% of the time the same gene. not useful for all antibiotics.

Answer 118

Severe sepsis sepsis with end organ dysfunction or hypoperfusion (indicated by hypotension, lactic acidosis or decreased urine output or others) Septic shock severe sepsis with persistently low blood pressure which has failed to respond to the administration of intravenous fluids.

Answer 119

both are target lesions. multeforme are small lesions, coin sized and all over the body. marginatum is the rash seen in tic bites lyme disease, these are one big rash that has an edge that migrates/expands and covers a large area.

Answer 120

as it causes phlebitis. you can give clarithromycin IV but as these have good oral bioavailability you should give PO as soon as the PT is able.

Answer 121

it does not have a peptidoglycan cell wall

Answer 122

gram positives have a thick peptidoglycan cell wall as the outermost surface. gram negatives have a thin peptidoglycan layer of cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane.

Answer 123

blood cultures if signs of sepsis sputum - M,C and S. urinary antigens - for legionella and streptococcus pneumoniae. also in the bigger centres sputum PCR can be used.

Answer 124

- infective endocarditis. this can cause weight loss, fatigue, and clubbing if around for long enough. on top of all the signs that are well known eg splinter haemorrhages.

Answer 125

Roth's spots are retinal hemorrhages with white or pale centers. Present-day analysis shows that they can be composed of coagulated fibrin including platelets, focal ischemia, inflammatory infiltrate, infectious organisms, or neoplastic cells. [1] They are typically observed via fundoscopy. They are usually caused by immune complex mediated vasculitis often resulting from bacterial endocarditis.

Answer 126

infective endocarditis can cause microscopic haematuria and proteinuria as vegetations are thrown off and damage the kidneys or immune complexes get stuck in there.

Answer 127

try to take 3 sets of blood cultures with 6 hours in between to show a persistant bacteraemia. only if clinically stable.

Answer 128

streptococci and enterococci. so cannot tell them apart under the microscope with gram staining. staphylococci are also gram positive cocci but form clusters not chains.

Answer 129

staph aureus.

Answer 130

bad dentition or recent dental surgery can allow strep viridians classically into the blood. these then settle on a valve and cause infective endocarditis.

Answer 131

means that they have amuch greater risk of having a colorectal malignancy. its not clear why this is, could be carcinogenic bacteria or it could be that the cancer allows this normal gut commensal an entry point into the circulation, but this is the association so you need to check.

Answer 132

Management of contacts: prophylaxis needs to be offered to household and close contacts of patients affected with meningococcal meningitis oral ciprofloxacin or rifampicin or may be used. The Health Protection Agency (HPA) guidelines now state that whilst either may be used ciprofloxacin is the drug of choice as it is widely available and only requires one dose the risk is highest in the first 7 days but persists for at least 4 weeks meningococcal vaccination should be offered to close contacts when serotype results are available, including booster doses to those who had the vaccine in infancy for pneumococcal meninigitis no prophylaxis is generally needed. There are however exceptions to this. If a cluster of cases of pneumococcal meninigitis occur the HPA have a protocol for offering close contacts antibiotic prophylaxis. Please see the link for more details

Answer 133

eukaryotes. they have chromosomes and organelles and give rise to plants, animals and fungi.

Answer 134

This is depend on the species involved but in unknown always treat for P. Falciparum. 1. P. Falciparium → quinine + tetracycline or doxycycline. 2. Non-falciparium → chloroquine + primaquine (used to improve liver clearance of ovale and vivax)

Answer 135

``` "Having Flu Symptoms Can Make Moaning Children A Nightmare": Headache Fever Sore throat Chills Myalgias Malaise Cough Anorexia Nasal congestion ```

Answer 136

``` narrow = gram positive bacteria only broad = gram positive and negative. no better than narrow spectrum against the staphs and streps. ultra = positive, negative and anaerobes. ```

Answer 137

staph = flucloxacillin meningitis = ceftriaxone UTI = trimethoprim atypicals (M.pneumo, chlamydia pneumo, legionella pneumophila) = erythromycin PO or clarithromycin IV. these don't have a cell wall so have to have an agent that attacks in the cell. clari also covers haemophilus.

Answer 138

``` pretty much all the same allergy otherwise quite safe can be given in children and pregnant. fine in normal renal function ``` big problem is that its cleaved by beta lactams

Answer 139

its a staph aureus that is resistant to flucloxacillin. methicillin is only used in the lab but reflects fluclox resistance

Answer 140

1 - MRSA 2 - WRE - vancomycin resistant enterococci. many are resistant to amoxicillin. 3 - coagulase negative staphylococci (CNS) - line infections and prosthetic infections. most resistant to fluclox. manage these problem agents with the GLYCOPEPTIDES. vancomycin and teicoplanin. jobs won't work in VRE. In VRE the first stop is the oxazolidinones e.g. linezolid (new, good penetration inc brain, but myelosuppression, peripheral neuropathy inc optic neuritis, can't give with MAOI) . or daptomycin

Answer 141

vancomycin and gentamycin. as both are nephrotoxic and make sure safe therapeutic levels.

Answer 142

not beta lactamase stable to not used in staph. can be used in strep but not empirically in sore throat due to EBV. used in cellulitis, pneumonias. TDS and well absorbed PO instead of other penicillins. it is the penicillin IV to oral switch agent. enterococcal infections and listeria.

Answer 143

you could as you have the beta lactam inhibitor but you wouldn't as you are giving too broad a spectrum and you could hit it with a narrower spect e.g. fluclox.

Answer 144

gram positive and negative and potent against anaerobes. aspiration pneumonia - as mouth flora, streps and anaerobes. chronic osteomyelitis in diabetics etc anything where gut organisms could translocate e.g. diverticulitis, appendicitis (or could use metronidazole for anaerobes and cefuroxime for the rest). tooth abcesses. CAP secondary to exacerbation of COPD to cover strep and haemophilus (as H. influenzae makes beta lactamase) sepsis when you don't know the cause. v. broad but doesn't cover pseudomonas = tazocin.

Answer 145

``` metronidazole - prototypic. co-amoxiclav - (but this will also attack all the normal bowel flora so reserve for where multiple organisms are possibly involved) tazobactam carbapenems (last resort) clindamycin ```

Answer 146

``` pseudomonas - some klebsiella - lots enterobacter - lots proteus serratia - lots acinetobacter - some ``` these tend to be multi drug resistant. due to ESBLs, extended spectrum beta lactamases so takes out beta lactams inc cephalosporins. cannot use cephalosporins as will cleave. some beta-lactamase inhibitors will also fail. the final chance is with carbapenems, these have beta lactam at the core still though, drug of choice but expensive.

Answer 147

lots of different types, just need to know the one that your hospital stocks. can be used to treat staphs but much higher MIC than fluclox so not as good. . UTI in pregnancy, if can't use amoxicillin. this is basically the only use of it at the moment. bad PO bioavail and tissue pen but conc in urine.

Answer 148

the 3 primary causes of bacterial meningitis - meningococcus, pneumococcus, H. influenzae

Answer 149

a lincosamide. similar to macrolides gram positive staph and strep and anaerobic but no gram negative. weird. acts on the ribosome and switches of toxin making machinery so good in necrotising fasciitis and toxic shock syndrome etc. alternative to flucloxacillin in orthopaedics as it penetrates bone and joint well. PO and IV. associated with c. diff

Answer 150

human herpes virus 5 = cytomegalovirus. this causes retinitis which can lead to blindness without treatment with ganciclovir. it can afffect other organ systems as well eg skin, GI tract, peripheral nerves and brain,

Answer 151

can reduce visual acuity and colour vision so do snellen and ischihara as a baseline before starting. causes a toxic optic neuropathy. this is largely reversible though.

Answer 152

a fever that peaks every third day with rigors, jaundice and general malaise. it should be suspected in all those who have a fever of unknown origin and have traveled to an endemic area.

Answer 153

fever, headache, rash, myalgia, arthralgia

Answer 154

headache and slow rising fever and a relative bradycardia. as it progressess you get a hepatosplenomegaly and a green pea soup diarrhoea. intestinal haemorrhage perforation and neurological complicaitons can occur.

Answer 155

HBsAG - denotes acute infection, if stilll present 6 months later then this denotes chronic infection HBcAG - denotes acute/chronic infection but is present for life anti-HBs this denotes immunity after vaccination or acute infection anti- HBe IgM - this lasts for less than 6 months after an acute infeection anti-HBc IgG this is a lifelong marker of past infection

Answer 156

a drug used to treat chronic HBV infection

Answer 157

a sore discharging ear can be associated with swimming in non sterile bodies of water pain increases with movement of the tragus. a topical treatment is the treatment of choice. gentamicin and hydrocortisone drops TDS

Answer 158

E. coli in most cases. | also some staph, klebsiella, enterococcus and proteus

Answer 159

pseudomonas aeruginosa, but patients can initially be infected by stpah aureus and h. influenzae but usually its pseudomonas by mid teens.

Answer 160

red sore area on face then it produces a lot of serous fluid before crusting over. mainly caused by staph aureus and treated with fusidic acid cream or in severe cases oral fluclox.

Answer 161

orange/red fluids cyp450 inducer hepatitis and liver failure

Answer 162

metronidazole ciprofloxacin clarithromycin

Answer 163

an anaphylactoid reaction due to vancomycin induced mast cell degranulation and release of histamine. usually due to an overly rapid infusion rate. pruritis and erythematous rash and usually disappears after discontinuation of the infusion. most severe reactions are inversely proportiona lto the age of the patient. .

Answer 164

gram negative bacteria convert nitrates to nitrites.

Answer 165

it doesnt require monitoring. vanco however is first line but is renally cleared, has a narrow therapeutic range and needs level monitoring for nephro and ototoxicity.

Answer 166

warfarin. reduces effectiveness by sequestering.

Answer 167

increase activity as its a prodrug.

Answer 168

VACATE AHA ``` V - valproate A - aminosalicylates C - chemo A - atypical antipsychotics T - thiazides E - estrogen due to lipid increasing effect ``` A - azathioprine H - HIV drugs A - antiglycaemic medic.

Answer 169

strep throat - although most get better on their own, good if you don't want to give amoxicillin due to rise of ebv rash - prophylaxis for splenectomy.

Answer 170

due to the MIC, its very high in order to dent strep vs staph so you need high doses which causes side effects. so you could treat in theory but not good in practice, add benpen.

Answer 171

clavulinic acid is highly emetogenic. use benpen and fluclox to cover streps and staphs

Answer 172

to prevent people accidentally giving it to people with penicillin allergies.

Answer 173

clusters of grapes

Answer 174

chains unless pneumococci where it is pairs.

Answer 175

linezolid - very narrow spectrum. high conc in tears and sweat. causes blood dycrasias and optic neuropathy (irreversible), can turn tongue black. can also mimic MAOI so risk of serotonin syndrome in SSRIs. used against VRSA staphs e.g. MRSA resistant to teicoplanin and vancomycin.

Answer 176

PT found to be MRSA carrier. exp what needs to be done. 1 - colonisation vs infection exp. 2 - what you're going to do and why. reduce numbers to reduce infection risk to ourself and others. not more virulent just more difficult to treat. 3 - chlorhexidine body wash and shampoo, mupirocin nasal ointment 4 - don't need to retest as the test is DNA based and will stay positive for a while even when bacteria are dead 5 - cannot eradicate but looking to suppress. 6 - other people at home don't need to go through it unless tested positive when admitted to hospital .

Answer 177

tend to cover pseudomonas

Answer 178

ceftazidime has poor gram positive.

Answer 179

ciprofloxacin - only one that is oral but resistance gentamicin ceftazidime tazocin meropenem - if the others haven't worked.

Answer 180

``` mild = 0-1 oral amoxicillin moderate = 2 = amox and clarith severe = 3 or above = co-amox and clarith ``` if pen allergy can use clari and teicoplanin.

Answer 181

macrolide is bacteriostatic but amoxicillin is bactericidal.

Answer 182

``` non-pneumonic = amox or doxy pneumonic = amoxi recurrent = co-amox ```

Answer 183

co-amoxiclav

Answer 184

90%- staph aurea 10% - beta haemolytic 1st line mild to mod = fluclox severe = benzylpen and fluclox. pen allergy = clindamycin .

Answer 185

teicoplanin - treat as if MRSA infection

Answer 186

co-amoxiclav to cover skin flora. consider tetanus prophylaxis.

Answer 187

most likely alpha group strep e.g. viridians. 1st line = amoxicillin and gentamicin if you know viridian group strep = benzylpen instead of amoxicillin as not resistant. 2 weeks iv then 4 weeks oral amox. IVDU or more fulminant e.g. high fever - staph aureus, very destructive. = fluclox prosthetic valve - new valve, skin flora e.g. CNS staph - teicoplanin + gentamicin + rifampicin - older than 6 weeks valve - normal viridans group - treat as native valve. pen allergy = teicoplanin and gentamicin for synergistic value.

Answer 188

many get better on their own or are viral. 1st line = ciprofloxacin as most are gram negative rods. e.g. salmonella. shigella (bloody) if campylobacter - diarrhoea, vomiting, really really bad abdo cramps is the differentialting factor over E coli. a helix gram negative, not a gram negative rod. most are resistant to cipro so use a macrolide e.g. erythromycin. if c. diff = oral metronidazole for 10-14 days. recurrence = vancomycin oral, doesn't work here if IV as wont cross gut. if really severe e.g. toxic megacolon use both metronidazole and vancomycin. if these all fail the 3rd line is fidaxomicin but never prescribed without consultant micro author.

Answer 189

sensory polyneuropathy = irreversible.

Answer 190

most = virus, most settle by themselves. choice of ABX is based on where they have been. africa or middle east = e. coli = oral ciprofloxacin asia and india = azithromycin due to cipro resistance giardia = slow course disease, nausea bloating, gassy, watery. tinidazole or metronidazole.

Answer 191

most gut bacteria = gram negatives. a few gram positives 1st line = cefuroxime for most + metronidazole for anaerobes. penicillin allergy = ciprofloxacin and metronidazole.

Answer 192

1st = co-amoxiclav penicillin allergy = ciprofloxacin and metronidazole if severe = cefuroxime and metronidazole

Answer 193

cefuroxime and metronidazole.

Answer 194

trimethoprim = 1 tablet twice a day for 3 days, or a week in men second line is nitrofurantoin

Answer 195

its antifolate. ABSOLUTE CI in pregnancy esp 1st trimester.

Answer 196

pulmonary fibrosis also CI in pre due to haemolysis in the newborn.

Answer 197

absolute CI

Answer 198

benpen in community ceftriaxone IV inhospital acyclovir if encephalitis possible if pneumococcus likely add dexamethasone if listeria poss add in ampicillin penicillin allergy = iv chloramphenicol.

Answer 199

gram positive diplococci - check

Answer 200

gram negative diploccoci

Answer 201

gram negative rod

Answer 202

they can look pretty ok but die within an hour or so.

infectious diseases Flashcards

(235 cards)