Step 1 - Micro 4

tifeyagi's version from 2016-06-30 03:19


Question Answer
Bartonella spp. 1. Cat scratch fever 2. Bacillary angiomatosis in immunocompromised patients (often confused with Kaposi’s sarcoma)
Borrelia burgdorferi1. Lyme disease 2. From tick bite - ixodes tick that lives on deer and mice
Brucella spp.1. Brucellosis/undulant fever 2. Dairy products, contact with animals
Francisella tularensis1. Tularemia 2. Tick bite, rabbits, deer
Yersinia pestis 1. Plague 2. Flea bite; rodents, especially prarie dogs
Pasteurella multocida1. Cellulitis 2. Animal bite, cats, dogs
Gardnerella vaginalis1 . Gram variable rod 2. Vaginosis presenting as gray vaginal discharge 3. Fishy smell 4. Nonpainful 5. Mobiluneus (anaerobe) also involved 6 clue cells 7. Metronidazole
Rickettsiaeobligate intracellular organisms that need CoA and NAD+ 2. Transmitted by arthropod vector (except coxiella - aerosol transmission) 3. Classic triad of headache, fever and rash (vasculitis), coxiella causes pneumonia 4. Treat with tetracycline
Rickettsial disease rashesRickets starts on hand and feet, typhus centrally and spreads outward without palmos or soles.
Rocky mountain spotted fevertick vector caused by rickettsia rickettsii - 2. Rash on palms and soles migrating to wrists ankles then trunk, headache, fever 3. Endemic east coast 4. treat with tetracycline
Endemic typhusflea vector caused by Rickettsia typhi- treat with tetracycline
Epidemic typhushuman body louse vector caused by rickettsia prowazekii- treat with tetracycline
Ehrlichiosistick vector caused by ehrlichia- headache, muscle ache, fatigue - treat with tetracycline
Q feverinhaled aerosols (no vector) - caused by coxiella burnetii- treat with tetracycline
Weil-Felix reactionpatients with Rickettsial infection have antibodies against rickettsia - patient serum mixed with proteus antigens = agglutination Coxiella is negative weil-felix
Chlamydiae1. Obligate intracellular (can’t make own ATP) 2. Two forms: Elementary body (small, dense, infectious enters cell via endocytosis), Reticulate body (replicated in cell by fission) 3. Laboratory diagnosis seen on Giemsa or fluorescent antibody-stained smear
Chlamydiae trachomatiscauses reactive arthritis, conjunctivitis, nongonococcal urethritis, PID
Chlamydiae pneumoniae, psittacicause atypical pneumonia - aerosol transmission
Chlamydia types A,B,Cchronic infection, cause blindness in Africa
Chlamydia types D-KUrethritis/PID, ectopic pregnancy, neonatal pneumonia, neonatal conjunctivitis.
Chlamydia L1-L3Lymphgranuloma venereum (acute lymphadenitis - positive frei test). Do not confuse with granuloma iguinale (donovanosis), which is caused by Calymmatobacterium granulomatis
Mycoplasma pneumoniaeClassic cause of atypical “walking” pneumonia (insidious onset, headache, nonproductive cough, diffuse interstitial infiltrate). X-ray look worse than patient. High titer of cold agglutinins(IgM) which can agglutinate or lyse RBCs. Grown on Eaton’s agar Membrane contains cholesterol. More common in pts <30y Frequent outbreaks in military recruits and prisons
Mycoplasma pneumoniae treatmenttetracycline or erythromycin (bugs are penicillin resistant b/c no cell walls)


Question Answer
Conidiaasexual fungal spores
Histoplasmosis1. Endemic in mississippi, ohio river valleys 2. Pneumonia 3. Hides within macrophages 4. In bird and bat droppings
Blasomycosis1. Endemic in states east of mississippi river and central america 2. Causes inflammatory lung disease and can disseminate to skin and bone 3. Causes granulomatous nodules 4. Blasto buds (broadly)
Coccidiodomycosis1. Endemic in SW US, Ca 2. Causes pneumonia and meningitis: can disseminate to bone and skin. 3. Case rate ↑ after earthquakes (sphenules are thrown up in the air) 4. Coccidio crowds in the spherule
Paracoccidiodomy1. Endemic in Latin america 2. Captain’s wheel appearance
Fungal treatment fluconazole or ketoconazole for local infection; amphotericin B for systemic infection - systemic mycoses can mimic TB (granuloma formation)
Tinea versicolor1. Cutaneous mycoses 2. Malassezia furfur 2. Degradation of lipids produces acids that damage melanocytes and cause hypopigmented patches. 3. Occurs in hot, humid weather. 4. Spaghetti and meatball appearance on KOH prep 5. Treatment with topical miconazole, selenium sulfide(Selsun)
Tinea pedis, cruris, corporis, capitisPruritic lesions with central clearing resembling a ring, caused by dermatophytes (Microsporum, Trichophyton, Epidermophyton) Mold hyphae in KOH prep - not dimorphic. Pets are a resevoir for Microsporum and can be treated with a topical azoles
Candida albicans1. Opportunistic fungal infection 2. Systemic or superficial fungal infection. 3. Yeast with pseudohyphae in culture at 20C germ tube formation at 37C (diagnostic) 4. Oral and esophageal thrush in immunocompromised (neonates, steroids, diabetes, AIDS) 5. Vulvovaginitis (high pH, diabetes, use of antibiotics) 6. Diaper rash 7. Endocarditis in IV drug users 8. Disseminated candidiasis (to any organ) 9. Chronic mucocutaneous candidiasis
Candida albicans treatmentNystatin for superficial infection; amphotericin B for serious systemic infection
Aspergillus fumigatus1. Allergic bronchopulmonary, lung cavity aspergilloma, invasive. 2. Especially in immunocompromised and those with chronic gramulomatous disease 3. Mold 4. Septate hyphae that branch at acute angles - think “A” for acute angles in aspergillus - not dimorphic
Cryptococcus neoformans1. Meningitis, cryptococcosis 2. Heavily encapsulated yeast - not dimorphic 3. Culture on sabourauds agar, stains with india ink 4. Latex agglutination test detects polysaccharide capsular antigen 5. Soap bubble lesions in the brain
Mucor and Rhizopus1. Mucormycosis 2. Mold with irregular nonseptate hyphae branching at wide angles 3. Disease mostly in ketoacidotic diabetic and leukemic patients 4. Fungi also proliferate in the walls of blood vessels and cause infarction and necrosis of distal tissue 5. Rhinocerebral frontal lobe abscesses
Make drawing of pictures - 159, 160, 161draw
Pneumocystis jiroveci1. Diffuse interstitial pneumonia 2. Yeast (used to be protozoan) 3. Inhaled 4. Most infections are asx 5. Immunosuppression predisposed to disease 6. Diffuse bilateral CXR 7. Diagnosed by lung biopsy or lavage - methenamine silver stain of lung tissue 8. Treatment by TMP-SMX, pentamidine, dapsone - start prophylaxis when CD4 drops <200cells/ml)
Sporothrix schenkii1. Dimorphic fungus that lives on vegetation 2. Introduced by thorn causes local pustule or ulcer with nodules along draining lymphatics (ascending lymphangitis) 3. Little systemic illness - cigar shaped budding yeast visible in pus. 4. Treat with itraconazole or potassium iodide
Giardia lamblia1. Transmission by cysts in water 2. Bloating, flatulence, foul smelling fatty diarrhea (often seen in campers/hikers) 3. Diagnosis by trophozoites or cysts in stool 4. Treatment with Metronidazole
Entamoeda histolytica1. Transmission by cysts in water 2. Bloody diarrhea (dysentary), liver abscess, RUQ pain - histology shows flask-shaped ulcer if submucosal abscess of colon rupture) 3. Diagnosis by serology 4. Treatment with metronidazole and iodoquinol
Cryptosporidium1. Transmission by cysts in water 2. Severe diarrhea in AIDS, mild disease (watery diarrhea) in non-immunocompromised 3. Cysts on acid fast stain 4. Treatment by prevention (by filtering city water supplies)
Toxoplasma gondii1. Transmission by cysts in meat or cat feces; crosses placenta 2. Brain abscess in HIV (ring enhancing brain lesion) 3. congenital toxoplasmosis - chorioretinitis, hydrocephalus and intracranial calcifications 4. Diagnosis by serology or biopsy 5. Treat with sulfadiazine + pyrimethamine
Naegleria fowleri1. Transmission by swimming in freshwater lakes - enter via cribiform plate 2. Diagnosed by amoebas in spinal fluid 3. Rapidly fatal meningoencephalitis 4. No treatment
Trypanosoma1. Gambiense or rhodesiense 2. Transmission by Tsetse flu - a painful bite 3. African sleeping sickness: enlarged lymph nodes, recurring fever (due to antigenic variation), somnolence, coma 4. Diagnosis by blood smear 5. Treatment with Suramin for blood borne disease, Melarsoprol for CNS penetration
Trypansoma cruzi1. Spread by “kissing bug” - a painless bite 2. Causes Chaga’s disease (dilated cardiomyopathy, megacolon, megaesophagus) - predomnantly in South america 3. Diagnosed by blood smear 4. Treated with nifurtimox
Leishmania donovani1. Spread by sandfly 2. Visceral causes spiking fevers, hepatosplenomegaly, pancytopenia 3. Diagnosed by macrophages containing amastigotes 4. Treated with Sodium stibogluconate but amphotericin if resistant
Plasmodium vivax/ovale1. Spread by mosquito (anopheles) 2. Cyclic fever that occur every other day - dormant form in liver 3. Diagnosis by blood smear 4. Treat with chloroquine, then mefloquine or with primaquine for dormant forms in liver
Plasmodium malarie1. Spread by mosquito 2. Cyclic fever, headache, anemia, splenomegaly 3. Diagnosis by blood smear 4. Treat with chloroquine, or meflquine if resistant
Plasmodium falciparum1. Spread by mosquito 2. Severe, daily cyclic headache, parasitized RBCs occlude capillaries in brain (cerebral malaria), kidneys, lungs 3.diagnosis by blood smear 4. Treat with chloroquine, mefloquine if resistant
Babesia 1. Spread by Ixodes tick (same as lyme disease) 2.. Diagnosis by blood smear - no RBC pigment = maltese cross 3. Fever and hemolytic anemia - predominantly in NE 4. Treat with quinine, clindamycin
Trichomonas vaginalis1. STD 2. Foul smelling, greenish discharge, itching and burning; do not confuse with gardneralla 3. Diagnosis by wet mount 4. Treat with metronidazole
Helminthmulticellular organism - life cycle involves stages in other organisms
Enterobius vermicularis (pinworm)1. Transmitted in food contaminate with eggs 2. Intestinal infection causes anal pruritis (scotch tape test) 3. Treat with bendazole or pyrantel pamoate 4. Type of roundworm
Ascaris lumbricoides1. Giant roundworm 2. Eggs are visible in feces 3. Intestinal infection 4. Treat with bendazoles or pyrantel pamoate 5. Type of roundworm
Trichinell spiralis1. From undercooked meat, usually pork 2. Causes inflammation of muscle (larvae encyst in muscle) and periorbital edema 3. Treatment with bendazoles 4. Type of roundworm
Strongyloides stercoralis1. Larvae in soil penetrate the skin 2. Intestinal infection causing vomitin, diarrhea and anemia 3. Treat with bendazoles or ivermectin 4. Type of roundworm
Ancylostoma duodenale, Necator amercanus1. Larvae penetrate skin of feet 2. Intestinal infection can cause anemia 3. Treat with bendazoles or pyrantel pamoate 4. Type of roundworm
Dracunculus medinensisguinea worm 1. Drinking water 2. Causes skin inflammation and ulceration 3. Treat with Niridazole
Onchocerca volvulus1. Transmitted by female blackflies 2. Causes hyperpigmented skin and river blindness - can have allergic reaction to microfloria 3. Treated with Ivermectin (Iver for River blindnesS) 4. Type of roundworm
Loa loa1. Transmitted by deer fly, horse fly and mango fly 2. Causes swelling in skin (can see worm crawling in conjunctiva) 3. Treat with diethylcarbamazine 4. Type of roundworm
Wuchereria bancfortia1. Transmitted by female mosquito 2. Causes blockage of lymphatic vessels (elephantitis) 3. Takes 9 months to 1 year after bite to get symptoms 4. Treat with diethylcarbamazine 5. Type of roundworm
Toxocara canis1. Transmitted by food contaminated with eggs 2. Causes granulomas (if in retina→blindness) and visceral larva migrans 3. Diethylcarbamazine 4. Type of roundworm
Taenia solium1. Transmitted by ingestion of larvae encysted in undercooked pork leads to intestinal tapeworm, ingestion of eggs causes cysticerosis and neurocysticerosis, mass lesions in brain. (swiss cheese appearance) 2. Praziquantel (use bendazoles for neurocysticercosis) 3. Type of tapeworm
Diphyllobothrium latum1. Transmitted by ingestion of larvae in raw freshwater fish 2. Causes vitamin B12 deficiency→anemia 3. Type of tapeworm 4. Treat with praziquantel
Echinococcus granulosus1. Transmitted by eggs in dog feces to lead to cysts in liver. 2. Causes anaphylaxis if echinococcal antigens are released from cysts (surgeons inject ethanol before removal to neutralize antigens) 3. Type of tape worm 4. Treat with bendazoles
Schistosoma1. Snails are host - cercariae penetrate skin of humans 2. Cause granuloma, fibrosis and inflammation of spleen and liver 3. Chronic infection with S. Haematobium can lead to SCC of the bladder 4. Treat with praziquantel 5. Fluke worm
Clonorchis sinensis1. Spread by undercooked fish 2. Causes inflammation of the biliary tract→pigmented gallstones 3. Associated with cholangiocarcinoma 4. Treat with praziquantel 5. Fluke worm
Paragonimus westermani1. Spread by undercooked crab meat 2. Causes inflammation and secondary bacterial infection of lung - causing hemoptysis 3. Treat with praziquantel 4. Fluke worm
Ingested nematodesenterobius, Ascaris, Trichinella (EAT)
Cutaneous nematodes Strongyloides, Ancylostoma, Necator (SANd)
Parasite showing brain cysts, seizuresTaenia solium (cysticercosis)
Parasite showing Liver cystsEchinococcus granulosus
Parasite showing B12 deficiencyDiphyllobothrium latum
Parasite showing Biliary tract disease, cholangiosarcomaClonorchis sinensis
Parasite showing HemoptysisParagonimus westermani
Parasite showing Portal hypertensionSchistosoma Mansoni
Parasite showing Hematuria, bladder cancerSchistosoma haematobium
Parasite showing microcytic anemiaAncylostoma necator
Parasite showing perianal pruritisEnterobius