Sketchy Micro

Giardia Lambia

(backpackers on river)

Infection: Camping/hiking contaminated water with cysts

Features: Diarrhea/steatorrhea, Affects fat soluble vitamin absorption

Dx: Trophozoite (look like shields) found in stool; ELISA stool antigen

Tx: Metronidazole

Entamoeba Histolytica

(archeologic site)

Infection: Fecal/oral transmission, anal sex

Features: Bloody diarrhea because invades colon wall (flask shaped ulcers), liver abscess (anchovy paste).

Dx: Stool O&P shows trophozoites with engulfed RBCs

Tx: Metranidazole/Paramycin/Iodoquinal

Cryptosporidium

(crypt)

Infection: HIV + usually, fecal/oral ingestion of cysts

Features: Profound diarrhea

Dx: Acid fast staining

Tx: Nitazoxanide, Spiromycin (macrolide)

Prevent: Oocytes can be removed by filtration

Toxoplasmosis

(cat lady)

Infection: Raw meat (cysts), feces in water (oocytes), animal feces, transplacental, affects immunocompromised and neonates

Features: chorioretinitis, hydrocephalus, deafness, intracranial calcifications

Dx: Ring enhancing lesions on MRI, differentiate from CNS lymphoma with biopsy

Tx: Sulfadiazine, pyramethazine

Prevent: Bactrim prophylaxis in CD4 <100 and IgG +

Trypansoma brucei

(sleeping beauty)

Types: Gambiense and Rhodesiense

Infection: Tse tse fly

Features: cervical lymphadenopathy, undulating fevers, coma (sleeping sickness)

Dx: Trypmastogores on blood smear

Tx: Suriamin (blood) and melarsoprol (CNS infection)

Naegleria fowleri

(Niagra falls)

Infection: fresh water, infects CNS via cribiform plate

Features: Rapidly fatal meningitis, encephalitis

Dx: Lumbar puncture

Tx: Amphotericin

Trypansoma cruzi

(che guevara)

Infection: Kissing bug in SA leaves feces on the skin that can get into wound/mucus membranes

Features: Acute form may show as fever or asymptomatic or Romana's sign. Chronic form can cause DCM, megacolon, mega esophagus

Dx: Blood smear

Tx: Nifurtimox

Babesia

(vampire babes)

Infection: Ioxdes tick, same as lyme disease found more in NE. More likely to cause problems in asplenic (SS)

Features: Hemolytic anemia > jaundice, sweating and fever

Dx: Maltese cross RBCs on blood smear

Tx: Atovaquone and azithromycin (macrolide)

Plasmodium

(African war lords)

Types: Vivax, ovale, falciparum, malariae

Infection: Anopholese mosquito in equatorial regions

Features: Cycling fever (V/O: every 4th day M: every 3rd day, F: irregular). Infected RBCs can occlude vessels > organ system damage/CNS sxs

Dx: Banana shaped parasite on microscopy (gametozoite) or rings in the RBCs (merozoite)

Tx: Chloroquine, primaquine + chloroquine (liver), mefloquine (caribbean), palanquine (prophylaxis in caribbean), Atovaquone + proguanil (caribbean), IV artesonate (severe), quinidine (resistant strains)

Malaria life cycle

Anopholese mosquito bites > sporozoites enter blood and go to liver > trophozoites form and burst out of the liver > merozoites infect RBCs > these form either gametozites or can be transmitted to another host

Malaria drugs

Chloroquine

primaquine + chloroquine (liver)

mefloquine (caribbean)

palanquine (prophylaxis in caribbean)

Atovaquone + proguanil (caribbean),

IV artesonate (severe)

quinidine (resistant strains)

Leishmania

(Desert mania)

Types: Braziliense and Donovani

Infection: Sand fly infects with promastigote > amastigote is engulfed by macrophages

Features: Cutaneous discoid ulcerated lesions, visceral (donovani) causes hyperpigmented spots, black fever, pancytopenia, hepatosplenomegaly, fatal

Dx: Purple stained nuclei with amastigotes in macrophages

Tx: Amphotericin

Trichomonas

Infection: STI

Features: cervicitis, vaginitis, strawberry cervix, burning, itching, yellow discharge

Dx: Wet mount showing motile trophozoites

Tx: Metronidazole

GI Nematodes

(superheroes)

Types:

Enterobius vermicularis (pinworms)

Ancylostoma duodenale, necator americanus (hook worm)*

Ascaris lumbricoides*

Strondyloides sterocoralis*

Trichonella spiralis

Infection: Pinworms are fecal/oral, (*) are skin - resp - GI, trichonella is from eating uncooked pork

Features: All cause some level of GI issue (itching > inflammation > vomiting). Hook worm causes severe iron deficiency anemia. Those with respiratory tract transmission can cause resp problems. All cause eosinophilia.

Dx: scotch tape test (pinworms)

Tx: Albendazole

Tissue Nematodes

(Horror movie characters)

Types and modes of transmission, treatment:

Dracunuculus medinesis (guinea worm): contaminated water, pull out with rod

Onchocerca volvulus (river blindness): black fly bite, ivermectin

Wucheria bancrofti (elaphantiasis): mosquitoes, diethylcarbamazine

Toxicara canis (dog roundworm, blindness): dog feces, albendazole

Loa Loa (eye worm): deer flies, diethylcarbamazine, albendazole

All cause eosinophilia

Cestodes

(circus/carnival)

Types: Tinnea soleum (pig) and sagginatum (cow):

Infection: Ingestion of eggs causes neurocystosarcosis (swiss cheese on MRI).

tx: paraziquantal, albendazole

Other cestodes:

Diphyllobothrium latum (fish) > B12 deficiency > megaloblastic anemia

Echinococcus granulosus (sheep) > egg shell calcifications in liver on CT

All cause eosinophilia

Histoplasma capsulatum

(historian's cave)

Infection: Ohio/MS river valley, caves, bat droppings, mold in the cold yeast in the beast

Features: pneumonia with granulomas (can look like TB), erythema nodosum, in IC can have hepatosplenomegaly

Dx: KOH - Macrophages filled with ovoid bodies (smaller than RBC), Rapid serum and urine antigen tests also

Tx: Azole drugs, amphotericin if systemic

Blastomycoses

(cannon/civil war)

Infection: Great lakes, Ohio river valley, mold in the cold yeast in the beast

Features: pneumonia with patchy alveolar infiltrate, systemic spread if IC (osteomyelitis, skin)

Dx: KOH - Broad based budding, same size as RBC, rapid urine antigen test

Tx: Azole drugs, amphotericin if systemic

Coccidioides

(presidio san juaquin)

Infection: San Juaquin valley, CA, more likely after earthquakes, mold in the cold but spherule of endospores in the body

Features: pneumonia with maybe cavities, arthralgias, erythema nodosum, meningitis, systemic spread if IC (osteomyelitis)

Dx: KOH - Spherules, larger than RBC or IgM against cocci

Tx: Azole drugs, amphotericin if systemic

Paracoccidioides

(piratas del sur)

Infection: South America, mold in the cold yeast in the beast

Features: pneumonia with granulomas, cervical lymphadenopathy, mucosal ulcers and cutaneous lesions

Dx: KOH - captains wheel

Tx: Azole drugs, amphotericin if systemic

Malessezia furfur

(italian restaurant)

Infection: hot and humid conditions, fungi stay in the top layer of skin, rarely due to TPN but can cause sepsis in neonates this way

Features: light and dark patches on the skin, back and chest, due to lipid degradation and damage to the melanocytes

Dx: KOH- spaghetti and meatballs on skin scrapings

Tx: selsun blue (selenium sulfate)

Tineas

(tin man)

Types: Trichophyton, epidermophyton, microsporum

Infection: Athletes at risk, can get from pets

Features: capis, corpis, cruris, pedis, itchy scaly rings, onchomycosis

Dx: KOH - hyphae on skin scrapings

Tx: Azole drugs, griseofulvan if serious

Sporothrix schnechii

(rose garden)

Infection: farm workers, rose gardeners, skin trauma allows the fungus to get in

Features: pustules follow the lymphatics

Dx: Biopsy shows cigar shaped budding yeast, multinucleated giant cells

Tx: Azole drugs, old tx: KI

Candida albicans

Infection: opportunistic, only at normal pH (4.0)

Features: causes thrush (IC, oral steroids) can be scraped off, vaginal candidiasis (OCPs, ABs, DM), diaper rash, endocarditis (IV drug users), esophageal (AIDS defining <100 CD4)

Dx: germ tubules @37, pseudo hyphae @20, catalase positive

Tx: Azoles, amphotericin for major infections, Nystatin for oral or esophageal

Aspergillus

(farmers)

Infection: Inhalation of condiophores, likely farm workers

Features: Allergic bronchopulmonary aspergillus (Type 1 HS Rxn) causes wheezing, fever. Can also cause aspergillomas fungus balls, associated with TB. If IC: angioinvasive leading to kidney failure, endocarditis

Dx: KOH - Acute branching with septations, condiophores with fruiting bodies

Tx: Azoles, amphotericin for major infections, Nystatin for oral or esophageal

Cryptococcus

(mummy crypt)

Infection: Pigeon droppings and soil, inhaled. Opportunistic and most likely to happen if IC, malignancy, steroids.

Features: Respiratory infection, meningitis (very bad)

Dx: Bronchopulmonary washes show soap bubbles. Tissue samples stain mucicarmine red or silver. Lumbar puncture, india ink with encapsulated halos. Soap bubble lesions on MRI.

Tx: Amphotericin + flucytosine, followed by fluconazole

Mucormycoses

(car shop)

Infection: IC, DM with ketoacidosis, spore inhalation

Features: Invades blood vessels, goes in via cribiform plate to CNS, necrosis (black eschar)

Dx: Biopsy shows hyphae that are non-septate with wide angle (90) branching

Tx: Amphotericin

Pneumocystis jiroveci

(ping pong)

Infection: IC (AIDS with CD4 <200)

Features: Insidious onset of pulmonary symptoms

Dx: ground glass on CXR, Methamine silver stain shows disc shaped yeast

Tx: Bactrim (pentadamine if sulfa allergy)

Prevent: Bactrim if CD4 <200

RNA + sense viruses

Picornaviruses

Calicivirus

Flavivirus

Togaviruses

Coronavirus

Retrovirus

Picornaviruses

Hep A

Enterovirus (Polio, cocksackie A and B)

Rhinovirus

Calicivirus

Norovirus

Falviviruses

Hep C

Dengue

Yellow Fever

West Nile Virus

Togaviruses

Rubella

Arbovirus (equine encephalitis, east, west and venezuelan)

Orthomyxoviruses

Influenza A, B, C

Paramyxoviruses

Measles

Mumps

RSV

Parainfluenza (croup)

Rhabdovirus

Rabies

Filovirus

Marburg

Ebola

Arena virus

Lymphocytic choriomeningitis

Riovirus

Rotavirus

Colorado tick virus