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Flashcards in Infectious Disease Deck (105)
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What is botulism?

gram-positive bacteria associated with home canned food products
-presents as muscle weakness and respiratory paralysis, "floppy babies"
-exposure to moist heat at 120 C (248 F) for 30 min kills the spores
-toxins, on the other hand, are readily destroyed by heat and cooking food at 80 C (176 F) for 30 min safeguards against botulism
-honey (no honey for babies) - it is recommended that you wait until your baby is at least 12 moths before introducing honey


What is the the tx fo botulism?

botulinum antitoxin


What is vaginal candidiasis?

-presents with vulvar itching, erythema and white curdy discharge
-KOH shoes hyphae


What is the tx for vaginal candidiasis?

miconazole cream x 1-7 days or fluconazole 150 mg PO single dose


What is esophageal candidiasis?

-very common in AIDS patients
-may present with substernal dysphagia, GE reflux, or nausea with or without pain
-diagnosis is by EGD with biopsy will demonstrate linear erosions on endoscopy


What is the tx of esophageal candidiasis?

treat with fluconazole


What is oral thrush?

friable white plaques that bleed if scraped


What is the tx for oral thrush?

treat with nystatin


What is intertrigo?

moist macerated areas, pruritic rash BEEFY RED ERYTHEMA with distinct scalloped borders and satellite lesions


What is the tx of intergtrigo?

treat with clotrimazole, ketoconaozle, miconazole, topical, keep the area dry


What is chlamydia?

the most common sexually transmitted infections
-gram-negative rods, intracellular
-asymptomatic, dysuria
-diagnosis: NAAT
-gram stain reveals no organisms


What is the tx for chlamydia?

(1) azithromycin 1 g PO x 1 (2) doxycycline 100 mg PO two times per days for 7 days
+ceftriaxone 250 mg IM x 1 to cover for gonorrhea
-erythromycin 500 mg QID x 7 days
-levofloxacin 500 mg P daily x 7 days
-in pregnancy: azithromycin 1 g PO single dose or amoxicillin 500 mg PO tid x 7 days


What is cholera?

an acute infectious disease of the small bowel caused by vibrio cholerae a gram-negative bacteria which secretes a toxin causes a life-threatening, rice water diarrhea


What are the characteristics of cholera?

-typically through contaminated water or seafood
-characteristics include severe "rice water" diarrhea with extreme fluid and electrolyte depletion, vomiting, muscle cramps, prostration, and potential death without replacement of fluids and electrolytes
-diagnosis is confirmed by stool cultures
-endemic areas: india, Southeast Asia, Africa, Middle East, southern europe, oceania, south, Central American


How do you tx cholera?

treat with oral rehydration + antibiotics (macrolides, fluoroquinolone, and tetracyclines


What is cryptococcus?

AIDS-defining illness, diagnose with CSF and serum serology


What are the charcterisitcs of cryptococcus?

-tranmission is through inhalation, budding yeast found in soil contaminated with pigeon/bird droppings
-India ink may be postive


What is the tx of cryptococcus?

treat with amphotericin B + flucytosine for two weeks followed by fluconazole for 10 weeks
-prophylaxis in HIV; fluconazole if CD4 <100


What is cytomegalovirus?

is an enveloped double-stranded linear DNA virus in the herpesvirus family
-it is also called human herpevirus 5
-it can cause infections that have a wide range of severity


What are the characteristics of cytomeglovirus?

-CMV can cause a syndrome that is similar to infectious mononucleosis but lacks severe pharyngitis
-CMV can cause pneumonia and inflammation of the retina (CMV retinitis) and esophagus in the immunosuppressed, especially in transplant recipients
-associated with a CD4 count < 50
-severe systemic disease can develop in neonates
-it is one of the TORCHES infections and can cause hearing loss, seizures, and petechial rash in newborns
-visulization of owl's eye inclusions in a cell sightly specific for cytomegalovirus


What is the tx of cytomegalovirus?

treatment is with Ganciclovir, valganciclovir, foscarnet, and cidofovir


What is diptheria?

URI with thick gray psudomembrane in the throat that bleeds ifs capped in someone who wasn't vaccinated
-patient may have neck swelling due to enlarged cervical lymphadenopathy (bull neck)
-rare in the US due to routine vaccination at 2, 4, 6, and 15-18 months with a booster at 4-6 years of age


What is the tx of diphtheria?

treat with antitoxin and antibiotic (penicillin or macrolide)


What is Epstein - Barr infection?

epstien barr mononucleosis is a viral illness characterized by a classic triad of fever + lymphadenopathy + pharyngitis


What are the characteristics of Epstein-Barr infection?

-diagnosed with positive heterophiles antibody screen (mono spot) - may not appear early in the illness (positive within 4 weeks)
-atypical lymphocytes with enlarged nuclei and prominent nucleoli
-maculopapular rash develops in 80% of patients treated with ampicillin
-left upper quadrant pain secondary to splenomegaly and are at risk for splenic rupture - athletes should avoid vigorous sports for at least the first three to four weeks of the illness


What is the tx for Epstein-Barr Infection?



What is gonococcal infections?

caused by neisseria gonorrhoeae - a gram-negative diplococcus
-women: often asymptomatic, prolonged infection can result in pelvic inflammatory disease when the bacterium travels into the pelvic peritoneum
-men: yellow, creamy, profuse and purulent discharge


What is the tx of gonococcal infections?

-ceftriaxone 125 mg IM x 1 + treatment for chlamydia (azithromycin 1 g PO single dose or doxycycline 100 mg PO BID for 7 days)


What is gonococcal pharyngitis?

is usually asymptomatic but may cause a sore throat
-neonatal conjunctitivits and pharyngitis
-disseminated infections can occur resulting in septic arthritis, tenosynovitis, and pustules on the hands and feet


What is herpes simplex infection?

-prodromal symptoms > 24 hours prior (burning, tingling) followed by painful grouped vesicles on an erythematous base


What is herpes simplex virus type 1?

gingivostomatitis, Bell's palsy, keratoconjunctivitis, cutaneous herpes, genital herpes, encephalitis, herpes lbialis, esophagitis, pneumonia, hepatitis


What is herpes simplex virus type 2?

gential herpes, cutaneous herpes, gingivostomatitis, neontal herpes, aseptic meningitis, disseminated infection, hepatitis


What is varicella-zoster virus?

-human herpesvirus 3
-chickenpox, herpes zoster, disseminated herpes zoster


What is Epstein-barr virus?

-human herpesvirus 4
-infectious mononucleosis, hepatitis, encephalitis, nasopharyngeal carcinoma, hodkin lymphoma, burkitt lymphoma, lymphoproliferative syndromes, oral hairy leukoplakia


What is human herpesvirus 6?

roseola infantum, otitis media with fever, encephalitis


What is human herpesvirus 7?

roseola infantum


What is kaposi sacroma-associated herpesvirus?

not a known cause of acute illness but has a causative role in Kaposi sarcoma and AIDS-related non-hodgkin lymphomas that grow primarily in the pleural, pericardial, or abdominal cavities as lymphomatous effusions
-also linked with multi centric cattleman disease


What is histoplasmosis?

AIDS-defining illness, associated with soil containing birds and bat droppings in the Mississippi and Ohio river valleys
-highest risk is with a CD4 <100, patients develop fever and mutliorgan failure, fulminant disease septic shock, and death are common
-increased alkaline phosphatase and LDH, (+) blood cultures if disseminated


What is the tx of histoplasmosis?

treat with itraconazole orally for weeks to months or amphotericin B if severe or failed itraconazole
-in general antigunal prophylaxis with itraconazole is not administered to prevent primary infection with special indications


What is the treatment for human immunodeficiency virus with a CD4 count 700-1,500?

disease normal


What is the treatment for human immunodeficiency virus with a CD4 count >500?



What is the treatment for human immunodeficiency virus with a CD4 count 500-200?

-tuberculosis, kaposi sarcoma, thrush, lymphoma, zoster
-primary prophylaxis: INH
-secondary prophylaxis: rifampin


What is the treatment for human immunodeficiency virus with a CD4 count <200?

-PJP, histoplasmosis
-primary prophylaxis: TMP/SMX, itraconazole
-secondary prophylaxis: dapsone, amphotericin B


What is the treatment for human immunodeficiency virus with a CD4 count <100?

-toxoplasmosis, cryptococcus
-primary prophylaxis: TMP/SMX, fluconazole
-secondary prophylaxis: pyrimethamine + sulfadiazine + colonic acid, amphotericin B


What is the treatment for human immunodeficiency virus with a CD4 count <50?

-MAC, CMV retinitis
-primary prophylaxis: valganciclovir
-secondary prophylaxis: Ganciclovir + foscarnet


What is the post exposure prophylaxis of HIV?

-PEP should be started within 72 hours of exposure
-the chances of contracting HIV from a needle stick injury involving a patient with known HIV is <0.3%
-testing should be done on worker and the patient - resting at 6 weeks, 3 months, and 6 months
-can take antiretrovirals - combo therapy with drugs from different classes should be continued for at least 4 weeks, full course PEP reduced the chance of HIV transmission by up to 70%


What is influenza?

everyone ages > 6 mo should receive annual influenza vaccination
-antiviral treatment reduces the duration of illness by about 1 day and should be specifically considered for high-risk patients


What is the tx of influenza?

Oseltamivir and Zanamivir (neuraminidase inhibitors) treat A + B


What is Lyme disease?

caused by borrelia burgdorferi (gram-negative spirochete) that is spread by lxodes (deer) tick
-transmission via tick bite (lxodes) - enters blood - spreads to tissues and organs; especially joints, heart, nervous system


What are the three stages of Lyme disease?

-locailzed disease (occurs 3-30 days after exposure) - non-painful, gradually expanding eythema mirgans (EM) "bull's-eye" rash appearing at the site of tick bite; feels warm to palpation; may itch
-constitutional: low-grade fever, chlls, headache, fatigue, myalgia, arthralgia, lymphadenopathy
-disseminated disease (days to months after exposure; multisystem involvement): musculoskeletal, flu-like syndrome, consisting of malaise, fatigue, chills, fever, headache, stiff neck, myalgias, and arthralgia that may last for weeks, cardiac (AV block)
-late/chronic disease (months to years after exposure): presence of nonspecific (e.g headaches, fatigue, joint pain) that persists after treatment for lyme disease


How is Lyme disease dx?

CDC testing criteria - two-tiered testing for lyme disease
-first test: enzyme immunoassay (EIA) or immunofluorescence assay (IFA)
-the second test (as needed): IgM and/or IgG western blot
-Other laboratory findings:
-blood chemistry: increased ESR, serum creatine phosphokinase, aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT)
-blood studies: anemia, leukocytosis, thrombocytopenia


What is the tx of Lyme disease?

-treat with doxycycline or amoxicillin (10-21 days) it started immediately after diagnosis
-prophylaxis: doxycycline 200 mg x 1 dose within 72 hours if lxodes tick


What is helminth infestations?

-helminth infections are all intestinal infections
-helminths are worm-like parasites that infect several species
-those that infect humans include the following:
-nematodes: roundworm (ascaris), hookworm, pinworm - cause GI symptoms and cough, treat with mebendazole
-pinworm: anal pruritus in a child in the morning, scotch tape test - the parent will go in early in the morning before the child wakes and apply scotch tape on the rectum and present for exam, also with pinworm paddles
-ascaris lumbricoides (roundworm) - most common internal helminth worldwide found in contaminated soil - small worm load will be asymptomatic, larger load may cause value abdominal symptoms, a high load may migrate to the pancreatin duct, bile duct, appendix, diverticula and cause symptoms at the site
-cestodes: tapeworm - cause GI symptoms and weight loss, treat with praziquantel
-trematodes: flukes, including Schistosoma, avian and mammal schistosomes (mercurial dermatitis or swimmer's itch)
-in any parasitic infection, eosinophilia may be presents


What is the tx of helminth infestations?

-pinworm and most other roundworms with mebendazole
-tapeworms and flukes with praziquantel


What is the presentation of malaria?

presents with periods chills, fever and sweats (fever every 3 days)
-caused by plasmodium vivax, p. malaria, p. oval, p. falciparum (most virulent)
-transmitted by anopheles mosquito
-splenomegaly typically after > 4 days of symptoms
-diagnose with giemsa stain peripheral smear (thin and thick) - parasites in RBCs, thrombocytopenia, increased LDH


What is the treatment of malaria?

treat with chlorquine or mefloquine for chloroquine-resistant p. falciparum


What are pinworms?

pinworms infection, also known as enterobiasis vermicularis is a human parasitic disease caused by the pinworm (a type of roundworm)
-the most common symptoms is itching in the anal area
-this can make sleeping difficult


What are the characteristics of pinworms?

-perianal itching especially at night (eggs are laid at night)
-eggs cling to the fingers while itching and are transmitted to other people either directly or through food or surfaces
-the eggs can thrive for 2-3 weeks on an inanimate object
-diagnosis is with a "scotch tape test" done in the early morning
-can see the eggs under microscopy


What is the tx fo pinworms?

treatment is with albendazole or mebendazole


What is toxoplasmosis?

toxoplasma gondii is a parasitic protozoan that causes the disease toxoplasmosis
-triad of encephalitis + chorioetinitis + intracranial calcifications in AIDS patients with a CD4< 100
-pregnant females with exposure to cat feces: toxoplasmosis is the reason we tell pregnant mother not to change cat litter
-CT of the brain shows ring-enchains lesions, Toxo Egg and IgM
-congential toxoplasmosis is part of ToRCH syndrome


What is the tx of toxoplasmosis?

prophylaxis for all HIB patients with CD4 count < 100 with Bactrim


What is pertussis?

Whooping cough (pertussis) is highly contagious respiratory tract infection marked by a severe hacking cough followed by a high-pitched intake of breath that sounds like a whoop
-gram-negative bacteria Bordetella pertussis - high contagious


What are the characteristics of pertussis?

-consider in adults with cough > 2 weeks, patients < 2 years
-catarrhal stage: cold-like symptoms, poor feeding, and sleeping
-paroxysmal stage: high-pitched "inspiratory whoop"
-convalescent stage: residual cough (100 days)


How is pertussis dx?

nasopharyngeal swab of nasopharyngeal secretions - culture


What is the tx of pertussis?

macrolide (clarithromycin/azithromycin); supportive care with steroids/beta2 agonists
-vaccinations 5 doses = 2, 4,6, 15-18 mo, 4-6 yrs (DTap)
-11-18 yo = 1 dose Tdap
-expectant mothers should getT Tdap during each pregnancy, usually at 27-36 weeks


What is pneumocystis?

AIDS-defining illness, associated with soil containing birds and bat droppings in the Mississippi and Ohio Rive Valleys
-originally called pneumocystis carinii pneumonia, then renamed pneumocystis jirovecii but still referred to as PCP
-most common opportunistic infection in patients with HIV especially if CD4 count <200


How is pneumocystis dx?

chest x-ray characteristically shows diffuse, bilateral perihilar infiltrates


What is the tx for pneumocystis?

trimethoprim-sulfamethoxazole (bactrim) and steroids
-if sulphate allergen, pentamidine
-prophylaxis with daily bactrim for high-risk patients with a CD4 count of less than 200 or with a history of PJP infection


What is rabies?

caused by a ribonucleic acid (RNA) rhabdovirus affecting mammals, including humans
-transmission via dogs, raccoons, skunks, bats, fox, coyote
-hydrophobia (inability to swallow water) is a classic symptom, pharyngeal spasms, aerophobia (fear of drafts of fresh air) and hyperactivity


How is rabies dx?

negri bodies (eosinophilic inclusion bodies in the cytoplasm of hippocampal nerve cells) are considered pathognomonic and are found in the brain of dead animals


What is the tx of rabies?

post-exposure treatment: rabies immunoglobulin + inactiavted vaccine (4 doses over 14 days)
-fatal when there are neurological symptoms


What is Rocky Mountain spotted fever?

caused by rickettsia rickettsia a species of bacterium that is spread to humans by the American dog tick (dermacentor variables)


What are the characteristics of Rocky Mountain spotted fever?

-2-14 days after tick bit will develop flu-like symptoms: fevers and chills, myalgia, and headache
-red maculopapular rash first on wrists and ankles (palms and soles) then spreading centrally over 2-3 days
-face is usually spared
-indirect fluorescent antibody (IFA) test remains the standard method of diagnosis of RMSF


What is the tx of Rocky Mountain spotted fever?

treat with doxycycline or chloramphenicol second line


What is salmonellosis?

although there are many types of salmonella, they can be divided into two broad categories: those the cause typhoid and enteric fever and those that primarily induce gastroenteritis:


What is enteric fever?

(salmonella typhi): a flu-like bacterial infection characterized by fever, GI symptoms, and headache
-transmitted via the consumption of fecally contaminated food or water
-GI symptoms may be marked constipation or "pea soup diarrhea"
-rose spots may be present (2-3 mm papule on trunk usually)
-more common in the developing world (usually immigration cases)


What is gastroenteritis?

(salmonella typhimurium, Enteritidis, and newport): results from improperly handled food that has been contaminated by animal or human fecal material
-it is estimated that 1 in 10,000 egg yolks is infected with salmonella Enteritidis


What is the tx for salmonellosis?

treat with ceftriaxone or other medications based on the sensitivity


What is shigellosis?

gram-negative bacteria shigella that results in watery diarrhea or dysentery (the frequent and often painful passage of small amounts of stool that contains blood, pus, and mucus)


What are the characteristics of shigellosis?

-the illness starts abruptly with diarrhea, lower abdominal cramps, and tenesmus accompanied by fever, chills, anorexia, headache, and malaise
-stools are loose and mixed with blood and mucus
-the abdomen is tender; dehydration is common


What is the tx for shigellosis?

treat with TMP-SMX or ciprofloxacin


What is syphilis?

is caused by the spirochete treponema palladium and has increased in incidence over the last 10 years; it is associated with risk-taking behavior such as drug use
-the disease has 3 phases, with an incubation of about 3 weeks


What is primary syphilis?

presents as a painless chancre in the genital or groin region persisting 3 to 6 weeks


What is secondary syphilis?

presents as an erythematous rash involving the palms and soles or a condyloma lata which is similar to lesions on primary syphilis in its infectivity but differs in appearance


What is tertiary syphilis (latent)?

affects about 30% and is a representation of widespread systemic involvement and can present with major vessel changes, such as in the aorta, permanent CNS changes (neurosyphilis), or even benign mucosal growths called gummas


How is syphilis dx?

diagnosis is by RPR/VDRL and confirmed by treponemal antibody-absorption test (FTA-ABS)
-lyme disease can cause a false positive


What is the tx for syphilis?

-IM benzathine penicillin for primary and secondary disease
-IV penicillin G (for gummas) for congenital and late disease


What is tetanus?

results from a toxin produced by the anaerobic bacteria Clostidium retain
-the toxin makes muscles become rigid and contract involuntarily (spasm)
-clostridium tetani spores are ubiquitous in soil
-the spores germinate in wounds where the bacteria produce a neurotoxin (tetanospasmin), which interferes with neurotransmission at spinal synapses of inhibitory neurons
-the result is uncontrolled spasm and exaggerated reflexes
-puncture wounds are most susceptible
-the elderly, migrant workers, newborns, and injection drug users are at particular risk


What are the symptoms of tetanus?

first symptom is pain and tingling at the site of inoculation
-later muscle spasms, respiratory muscle tetany, and lockjaw
-gram postive organism
-transmission: rusty nail


What is the tx of tetanus?

treat with immunoglobulin, wound debridement and penicillin
-prognosis: high mortality


What is the vaccination for tetanus?

-DTaP is usually given at 2, 4, 6, and 12 to 15 months, with an additional dose at 4 to 6 years
-Tdap adolescent preparation is recommended at age 11 to 12 years for those who have completed the recommended childhood DTP/DTaP vaccination series and have not received tetanus and diphtheria toxoid (td) booster dose
-subsequent boosters of Tdap are recommended every 10 years


What is toxoplasmosis?

toxoplasma gondii is a parasitic protozoan that causes the disease toxoplasmosis
-triad of encephalitis + chorioretinitis + intracranial calcifications in AIDS patients with a CD4 < 100
-pregnant female with exposure to cat feces: toxoplasmosis is the reason we tell pregnant not to change cat litter
-CT of the brain shows ring-enhancing lesions
-toxo IgG and IgM
-congential toxoplasmosis is part of ToRCH syndrome


What is the tx for toxoplasmosis?

prophylaxis for all HIV patients with CD4 count < 100 with Bactrim


What is tuberculosis?

organism: mycobacterium tuberculosis
-presentation: cough, night sweats, weight loss, post-tussive rales endemic area, immunocompromised
-xray: cavitary lesions, infiltrates, ghon complexes in the apex of lungs
-acid-fast bacilli stain
-biopsy: caveating granulomas


When is the Mantoux skin test positive?

- > 5 mm: patients at high risk of developing active TB if infected, such as those who have chest x-ray evidence of past TB, who are immunosuppressed because of HIV infection or drugs (eg TNF - alpha inhibitors, corticosteroid use equivalent to prednisone 15 mg/day for > 1 mo), or who are close contacts of patients with infectious TB
- > 10 mm: patients with some risk factors, such as injection drug users, recent immigrants from high-prevalence areas, residents of high-risk settings (eg prisons, homeless shelters), patients with certain disorders (eg silicosis, renal insufficiency, diabetes, head or neck cancer), and those who have had gastrectomy or jejunoileal bypass surgery
- > 15 mm: patients with no risk factors (who typically should not be tested)


What is the treatment for latent TB?

-rifampin (RIF) daily for four months (regiment abbreviations: 4R)
-isoniazid (INH) and RIF daily for three months (regimen abbreviations: 3HR)
-isoniazid 5 mg/kg (300 mg maximum) orally daily for 9 months
-isoniazid 5 mg/kg (300 mg maximum) orally daily for 6 months
-isoniazid 15 mg/kg (900 mg maximum) orally twice weekly for 9 or 6 months


What is the treatment for active TB?

-active treatment: quad therapy - isoniazid, rifampin, ethambutol, pyrazinamide for 8 weeks - peripheral neuropathy (give with B6)
-rifampin - orange body fluids, hepatitis
-ethambutol - optic neuritis, red-green blindness
-pyrazinamide - hyperuricemia


What is the prophylaxis treatment for household members of patients that have TB?

isoniazid for 1 year


What is varicella (chickenpox)?

primary infections - cluster of vesicles on an erythematous base
-dewdrops on a rose petal in different stages
-it starts on the face and spreads down
-acutely causes chickenpox - becomes latent in the Doral root ganglion
-symptomatic treatment may use acyclovir in special populations


What is Herpes zoster (shingles)?

varicella reactivation causing a maculopapular rash along one dermatome
-identified via tzanck smear with visualization of multinucleate giant cells


What is zoster opthalmicus?

shingles involving CCN V, dendritic lesions on slit lamp exam if keratoconjunctivits is present


What is zoster optics (Ramsay-hunt syndrome)?

facial nerve (CN VII) otalgia, lesions on the ar, auditory canal and TM, facial palsy auditory symptoms


What is the tx of shingles?

acyclovir, valacyclovir, and famciclovir - given within 72 hours to prevent post-herpetic neuralgia


What is postherpetic neuralgia?

pain > 3 months, paresthesia or decreased sensation
-treat with gabapentin or TCA, topical lidocaine gel, and capsaicin


What are the characteristics of the shingles vaccine?

herpes zoster vaccine is a liver, attenuated virus vaccine - vaccination is recommend for immunocompetent adults > 60 years of age