Worms

Question 1

Schistosomiasis: Acute disease

Answer 1

 Cercarial dermatitis

 Katayama fever = fevers, abdominal pain, eosinophilia

Question 2

Schistosomiasis: Chronic disease

Answer 2

 granulomatous colitis (S. mansoni)

 portal hypertension (S. mansoni)

 granulomatous cystitis (S. haematobium)

 bladder fibrosis and cancer (S. haematobium)

 CNS disease (eggs to brain/spinal cord, esp S. japonicum)

Question 3

Katayama Fever

Answer 3

Acute Schistosomiasis

• fever, myalgias, abdominal pain, headache, diarrhea, urticaria
• Eosinophilia, ^AST, ^alkaline phosphatase

Question 4

When to consider Schistosomiasis

Answer 4

• Fresh water exposure in an endemic region.
• Acute: Fever, abd pain, myalgias, eosinophilia
• Chronic: schistosomiasis (abdominal pain, blood in stool, loose stools, evidence of portal HTN, hematuria, eosinophilia)

Question 5

Fasciola hepatica (a liver fluke)

Risk factors:

S&S:

Dx:

Answer 5

• acquired by eating encysted larvae on aquatic vegetation (e.g. water chestnuts)
• fluke migration through the liver: RUQ pain and hepatitis; can induce biliary obstruction
• Dx: eggs in stool exam (low sensitivity), serology

Question 6

Clonorchis sinensis “Chinese Liver Fluke”

Opisthorchis viverrini Southeast Asian Liver Fluke”

Chronic complications

Answer 6

• biliary obstruction
• cholelithiasis
• cholangiocarcinoma

Question 7

HTLV-1 infection

(worms)

⇔

Answer 7

Strongiloides sterocoralis

Question 8

Taenia solium ⇔

Taenia saginatum ⇔

Diphyllobothrium latum ⇔

Answer 8

Taenia solium ⇔ pork, Neurocysitcercosis

Taenia saginatum ⇔ beef

Diphyllobothrium latum ⇔ B12 deficiency

Question 9

Paragonimus westermani “lung fluke”

Answer 9

freshwater crabs and crayfish; undercooked seafood

Adults migrate to LUNGS, frequent EOSINOPHILIA

• fever, cough, diarrhea during acute migration
• later, may have chest pain as worms migrate through lungs
• can develop chronic pulmonary symptoms

Dx: Sputum and/or stool exam for eggs.

Question 10

Echinococcus granulosus - Most cysts (65%) in the liver 25% in the lung

Common presentations

Answer 10

• allergic symptoms/anaphylaxis due to cyst rupture after trauma
• cholangitis and biliary obstruction due to rupture into biliary tree
• peritonitis b/c intraperitoneal rupture
• pneumonia symptoms due to rupture into the bronchial tree

Typically treat with albendazole for several days before surgery or PAIR (usually 2d-1wk before, and 1-3 months after)

Question 11

Enterobius vermicularis (pinworm)

Answer 11

• Humans are the only hosts
• peri-anal itching in some pts Dx: “scotch tape test” or swube, eggs with one flat side

Rx: albendazole, mebendazole, or pyrantel pamoate single dose repeat in 2 wks b/c risk reinfection.

 treat all members of households

Question 12

Body location of filarial infections

Answer 12

Wuchereria bancrofti / Brugia malayi (lymphatic filariasis) –mosquitoes–

• lymphatics

Loa loa (eyeworm) –Chrysops flies–

• SQ tissues (moving)

Onchocerciasis (river blindness) –blackflies–

• SQ tissues (nodules)

Question 13

Onchocerca lupi -> an infection of wolves

Answer 13

as with O. volvulus, is transmitted by blackflies - 6 human cases reported to date - 3 with deep nodules near cervical spinal cord - Southwestern U.S.(Arizona, New Mexico, Texas)

Question 14

Trichinellosis

Answer 14

Eat meat containing cysts (pork, boar, horse, wild game)

ABDOMINAL CRAMPS and DIARRHEA IF HEAVY INFXN

Larvae migrate to striated muscle, causing:

• SEVERE MUSCLE PAIN
• PERIORBITAL EDEMA
• EOSINOPHILIA +/- fever and urticaria

Question 15

Angiostrongylus cantonensis (the rat lungworm)

Answer 15

• Primarily found in SE Asia, Pacific basin, Caribbean (Jamaica)
• Caused by ingestion of parasites in snail or slugs (often on vegetables) OR ingestion of paratenic hosts (prawns, shrimps, crabs)
• In humans, develop to young adults and cause meningitis 1-2 weeks after infection

Question 16

Anisakis

Answer 16

> undercooked seafood/sushi (found worldwide);

> parasite buries its head into gastric mucosa.

Symptoms 1) due to invasion of worm (pain, vomiting) 2) due to allergic rxn to worm (mild urticaria, itchy sensation back of throat, anaphylactic shock)