Parasitology Flashcards
Pt presents with bloating, flatulence, foul smelling, fatty diarrhea
Giardia Lamblia causing giardiasis
Trasmitted via cysts in water
dx when multinucleated trophozoites or cysts are found in stool and antigen detected
tx: metronidazole
Pt presents with bloody diarrhea and RUQ pain. It was later found that they had a liver abscess and flask shaped ulcers in their colon.
Entamoeba histolytica
transmitted via cysts in water
Entamoeba eats erythroctes - trophozoites engulf the RBCs
tx with metronidazole
Pt was dx with AIDS 3 years prior and now presents with severe diarrhea. Oocysts were identified on an acid fast stain
Cryptosporidium
Severe diarrhea in aids
Mild dz if immunocompetent (give nitazoxanide)
Prevent by filtering water supplies
Pt is a newborn that presents with chorioretinitis, hydrocephalus, and intracranial calcifications
This is the classic triad for Congenital toxoplasmosis caused by toxoplasma gondii
If reactivation in AIDS then see brain abscesses on MRI
Cysts in meat (most common) or oocytes in cat feces. Crosses placenta and so pregnant women should avoid cats
Tx with sulfadiazine + pyrimethamine
Pt went swimming in a warm freshwater lake and then developed meningoencephalitis
Naegleria fowleri
Enters via cribriform plate
Dx when amoebas are found in the CSF
Tx with Amphotericin B
Pt was bit by a fly and now presents with enlarged lymph nodes, recurring fever, somnolence, coma
Trypanosoma brucei
Tsetse fly
Trypomastigote in blood smear
Tx with suramin for bloodborne disease or melarsoprol for CNS penetration (“melanin helps with sleep”)
Pt presents with fever, headache, anemia, and splenomegaly
Malaria due to plasmodium spp thats transmitted via anopheles mosquito
Plasmodium vivax/ovale - 48 hr cycle, fever on first and 3rd day, dormant form (hypnozoite) in liver
Plasmodium falciparum - severe irregular fever patterns. Cerebral malaria where parasitized RBCs occlude capillaries in brain, kidneys, lungs
Plasmodium malariae - 72 hr cycle
on blood smear you see trophozoite ring within RBC, schizont containing merozoites, red granules (Schuffner stippling) throughout RBC cytoplasm seen with P vivax/ovale
Pt was bit by a tick and now presents with fever and hemolytic anemia. Pt is from northeastern untied states
Babesia from Ixodes tick
Babesiosis - fever and hemolytic anemia. Asplenia increases severity of dz
look for ring form and latese cross on blood smear
Pt is from South America and presents with one eye appearing swollen shut after being bit by a bug
This is the Romana sign due to the bite of a triatomine bug which is a reduviid bug that deposits feces in a painless bite
Chagas disease- dilated cardiomyopathy with apical atrophy, megacolon, megaesophagus
See trypomastigote in blood smear
Visceral and cutaneous Leishmaniasis
Leishmania donovani
Visceral - spiking fevers, hepatosplenomegaly, pancytopenia
Cutaneous- skin ucers
Spread via sandfly. Macrophages containing amastigotes
Pt presents with foul smelling green discharge from vagina accompanied with burning and itching. You note a “strawberry cervix”
Trichomonas vaginalis
STI
Trophozoites (motile) on wet mount
Pt received the tape test in the anal region and saw eggs
Enterobius vermicularis (pinworm)
Ascaris lumbricoides (giant roundworm)
obstruction at ileocecal valve
biliary obstruction
intestinal perforation
migrates from the nose/mouth
knobby coated oval eggs in feces under microscope
Strongyloides stercoralis (thread worm)
Larvae in soil penetrate skin
Autoinfection: some larvae may penetrate the intestinal wall to enter the bloodstream without leaving the body
Ancylostoma duodenale, Necator americanus (hook worms)
microcytic anemia by sucking blood from intestinal wall
cutaneous larva migrans - pruritic, serpiginous rash from walking barefoot on contaminated beach
Trichinella spiralis
From undercooked meat (esp pork)
Larvae enter bloodstream, encyst in striated mm and cause inflammation
Trichinosis - fever, vomiting nausea, periorbital edema, myalgia
Trichuris trichiura (whipworm)
Loose stools, anemia, rectal prolapse in children due to heavy infection
Toxocara canis
Visceral larva migrans - nematodes migrate to blood through intestinal wall causing inflammation and damage
Heart, liver, eyes, and CNS
Onchocerca volvulus
Female blackfly
causes river blindness - black flies, black skin nodules, black sight
Loa Loa
Swelling in skin
Worm in conjunctiva
deer fly, horse fly, mango fly
Wuchereria bancrofti
Lymphatic filariasis (elephantiasis) - worms invade lymph nodes –> inflammation –> lymphedema
female mosquito
Taenia solium
Intestinal tapeworm: Ingestion of larvae encysted in undercooked pork
Cysticercosis, neurocysticercosis (cystic CNS lesions, seizures) : ingestion of eggs in food contaminated with human feces
Diphyllobothrium latum
Vitamin B12 deficiency (tapeworm competes for B12) –> megaloblastic anemia
Ingestion of larvae in raw freshwater fish
Echinococcus granulosus
Hydatid cysts “eggshell calcification” in liver
cyst ruptures and causes anaphylaxis
Ingestion of eggs in food contaminated with dog feces
Schistosoma
S. Mansoni , egg with lateral spine- liver and spleen enlargement, fibrosis, inflammation, portal hypertension
S. Haematobium , egg with terminal spine- squamous cell carcinoma of the bladder, painless hematuria, pulmonary HTN
Clonorchis sinensis
Biliary tract inflammation - pigmented gallstones
cholangiocarcinoma
undercooked fish
Sarcoptes scabiei
mites burrow into stratum corneum
serpiginous burrows in webspace of hands and feet
tx with permethrin cream
pediculus humanus phthirus pubis
Blood sucking lice
can transmit Rickettsia prowazekii (epidemic typhus) Borrelia recurrentis (Relapsing fever) Bartonella quintana (trench fever)
