Micro

Question 1

Giardia lamblia

Answer 1

Protozoa
Bloating, flatulence, foul-smelling, fatty diarrhea
Campers/hikers
Transmitted cysts in water
Multinucleated trophozoite or cysts in stool
Tx metronidazole

Question 2

Entamoeba histolytica

Answer 2

Protozoa
Bloody diarrhea, liver abscess w anchovy paste exudate, RUQ pain
Histo: flask-shaped ulcer
Trasnmitted cysts in water
Trophozites w engulfed RBCs or multinucleate cysts in stool
Tx: metronidazole, iodoquinol for asymptomatic carriers

Question 3

Cryptosporidium

Answer 3

Protozoa
Severe diarrhea in AIDS
Mild, watery diarrhea in immunocompetent
Transmitted oocytes in water
Oocytes on acid-fast stain
Prevent by water filtration
Tx: nitazoxanide for immunocompetent

Question 4

Enterobius vermicularis

Answer 4

Nematode
pinworm
Intestinal infection --> anal pruritus
Scotch tape test diagnosis
Fecal-oral
Bendazoles

Question 5

Ascaris lumbricoides

Answer 5

Nematode
giant roundworm
Intestinal infection --> possible obstruction of ileocecal valve
Fecal-oral
Eggs visible in feces under microscope
Bendazoles

Question 6

Strongyloides stercoralis

Answer 6

Nematode
threadworm
Intestinal infection --> vomiting, diarrhea, epigastric pain (mimics peptic ulcer disease!)
Larvae in soil penetrate skin
Ivermectin or bendazoles

Question 7

Ancylostoma duodenale, Necator americanus

Answer 7

Nematode
hookworms
Intestinal infection –> anemia by sucking blood from intestinal wall
Cutaneous larva migrant: pruritic, serpiginous rash from walking barefoot on contaminated beach
Larvae penetrate skin
Bendazoles or pyrantel pamoate

Question 8

Trichinella spiralis

Answer 8

Nematode
Intestinal infection: larvae enter bloodstream –> encyst in striated muscle cells –> inflammation of muscle (myalgia)
Trichinosis: fever, vomiting, nausea, periorbital edema, myalgia
Fecal-oral; undercooked meat (pork!)
Bendazoles

Question 9

Toxocara canis

Answer 9

Nematode
Visceral larva migrant: nematodes migrate to blood through intestinal wall --> inflammation and damage
Organs often affected: heart, liver, CNS
Fecal-oral (cat or dog feces)
Bendazoles

Question 10

Onchocerca volvulus

Answer 10

Nematode
Skin changes, loss of elastic fibers, river blindness
Allergic rxn to microfilaria
Transmitted by female blackfly
Ivermectin

Question 11

Loa loa

Answer 11

Nematode
Swelling in skin, worm in conjunctiva
Transmitted by deer fly, horse fly, mango fly
Diethylcarbamazine

Question 12

Wuchereria bancrofti

Answer 12

Nematode 
Elephantiasis: worms invade lymph node--> inflammation --> blocked lymphatic vessels
9mo-1yr for bite to be symptomatic 
Transmitted by female mosquito
Diethylcarbamazine

Question 13

Taenia solium

Answer 13

Cestode
Intestinal tapeworm - larvae encysted in pork - praziquantel
Cysticercosis, neurocysticercosis - eggs contaminated w human feces - praziquantel, albendazole (for neuro)

Question 14

Diphyllobothrium latum

Answer 14

Cestode
Vit B12 deficiency (bc tapeworm competes for it in intestine) –> megaloblastic anemia
Larvae from raw freshwater fish
Praziquantel

Question 15

Echinococcus granulosus

Answer 15

Hydatid cysts in liver –> anaphylaxis if antigens released (cysts injected to kill daughter cysts before removal)
Eggs in dog feces, sheep are intermediate host
Albendazole

Question 16

Schistosoma

Answer 16

Trematodes
Hepatoslpenomegaly (S mansoni - egg w lateral spine), fibrosis, inflammation
Chronic infection (S haematobium - egg w terminal spine) –> SCC of bladder w painless hematuria and pulmonary HTN
Snails are host, cercariae penetrate human skin
Praziquantel

Question 17

Clonorchis sinensis

Answer 17

Trematode
Biliary tract inflammation --> pigmented gallstones
Assoc w cholangiocarcinoma
Undercooked fish
Praziquantel