Tissue Invasive Nematodes

Question 1

How do we get Trichinella Spiralis?

Answer 1

Undercooked meat will give us this intestinal nematode

Question 2

Discuss the pathology and symptoms of Trichinella Spiralis

Answer 2

Sx: fever, vomiting, muscle pain/myalgia , abdominal cramps, periorbital edema, myocarditis, encephalitis, pneumonia

Path: larvae ingested → mature in intestine→ larvae shed into blood stream → deposit in striated muscle as new cysts (also in brain and heart)

Question 3

Discuss the lab values and how we diagnose Trichinella Spiralis

Answer 3

Labs: Eosinophilia
Dx: muscle biopsy (often insensitive); serology

Question 4

Treatment for Trichinella Spiralis?

Answer 4

Tx:Albendazole (disrupts microtubules)

Question 5

Discuss the pathology of Strongyloides stercoralis

Answer 5

intestinal nematode: (hookworm)
foot (skin)– blood –lungs – gi– feces
eggs laid in intestinal wall repenetrate and enter blood stream
intestinal nematode: (hookworm)
foot (skin)– blood –lungs – gi– feces
eggs laid in intestinal wall repenetrate and enter blood stream

Question 6

How does Strongyloides present?

Answer 6

sx: diarrhea, bloating

Question 7

Discuss the diagnosis and treatment for strongyloides

Answer 7

dx: larvae in stool
tx: Albendazole , ivermectin; steroids contraindicated

Question 8

Pathology and presentation of Enterobius vermicularis

Answer 8

intestinal nematode: (pinworm)
enterobiasis
ingestion of pinworm eggs, by hands, food, or water
sx: itching in the anal area where eggs are lain

Question 9

How to diagnose and treat enterobius vermicularis

Answer 9

dz: eggs on scotch-tape test
tx: Albendazole

Question 10

What the hell is Angiostrongylius cantonensis? Where do we get it from?

Answer 10

tissue trematode: (rat lungworm)

most common cause of eosinophilic meningitis worldwide

source: ingesting infected snails or slugs, prawns or crabs (paratenic hosts), or (snail) contaminated vegetables

Found in SE Asia and Caribean

Question 11

Discuss the pathology and presentation of Angiostrongylius cantonensis

Answer 11

In rats, adults develop in 2-3 weeks and migrate from brain surface to pulmonary arteries through venous system
In humans, adults develop and cause meningitis 1-2 weeks post infection

Question 12

How do we diagnose and treat Angiostringylius cantonensis?

Answer 12

Dx: CSF eosinophilia + meningitis + exposure history

Tx: corticosteroids may help

Question 13

Three presentation types of Filariasis

Answer 13

threadlike worms coming out of skin

Lymphatic filariasis (Wuchereria bancrofti and Brugia malayi)can be asymptomatic or cause lymphangitis ( acute filarial lymphangitis is inflammatory nodule with descending lymphangitis due to adult worms. Can cause dermatolymphngioadenitis (acute dermatolymphangioadenitis is ascending bacterial cellulits /lymphangitis). Can also cause lymphatic obstruction (lymphedema, elephantiasis, hydrocele)

pulmonary eosinophilia which manifests as paroxysmal nocturnal asthma, pulmonary infiltrates

Question 14

Discuss source and labs we see for filariasis in general

Answer 14

abs: blood eosinophilia, IgE elevation, and/ or filarial antibody titers
Source: spread by black flies (Simulium type) and mosquitoes.

Question 15

Treatment of Filariasis

Answer 15

Tx: elevation, hygiene, foot care, cutaneous fungal infections/ bacterial infections

Question 16

Discuss the source and location for Wuchereria

Answer 16

source: mosquito
lavae introduced to skin – invades lymphatics– blood
location: found in tropics

Question 17

Discuss the disease progression of Wucheria bancrofti

Answer 17

Dz: Chronic Lymphatic filariasis → elephantiasis; also cough from filariasis in lungs
granulomas obstruct the lymphatic system → lymphedema

Question 18

How do we diagnose and treat Wucheria bancrofti?

Answer 18

Dx: see microfilariae in nightime blood smear, or detection of antigen, or adult worm (biopsy or U/S)
tx: diethylcarbamazine (DEC)

Question 19

Discuss the source and pathogenesis of onchocerca volvulus

Answer 19

source: blackfly
location: Africa, Americas
larvae introduced to skin– adults mate in subcutaneous fat layer of the skin– microfila enter lymph and blood – accumulate in skin and eye

Question 20

Sympoms for onchocerca volvulus

Answer 20

dz: Subcutaneous filariasis and river blindness
sx: nodules under the skin, hyper/hypopigmented spots, severe itching, hanging groin, and blindness (begins as punctate keratitis)

Question 21

Discuss the diagnosis and treatment for onchocerca volvulus

Answer 21

dx: microfilariae on microscopy of skin punch biopsy, serology, nodulectomy
tx: ivermectin

Question 22

Discuss Loaloa

Answer 22

“african eyeworm”
Vector: deer fly
host: human only (no reservoir)
blood borne microfilariae
adult worms live in subcutaneous tissue
found in Africa

Question 23

Symptoms for Loa loa

Answer 23

Sx: may be asymptomatic, non-specific (fatigue, urticaria, arthralgia, myalgia)
subcutaneous angioedematous swelling (calabar swelling), eyeworm (does not cause blindness)

Question 24

Diagnosis and treatment for Loa loa

Answer 24

Dx: ID adult worm in conjunctiva, microfilaria seen in noon blood smear, or clinical picture + antifilarial antibodies
Tx: DEC

Question 25

What causes heartworm?

Answer 25

Dirofilaria Immitis (Heartworm)

Question 26

What type of bug is Toxocariasis and how do we get it?

Answer 26

tissue nematodes
Humans acquire infection by ingestion of eggs in dog/cat feces. Larvae hatch in intestine and travel to liver, spleen, lungs, brain, and/ or eye

Question 27

Symptoms of Toxocriasis

Answer 27

Sx: visceral larva migrans in 2-5 y.o.: fever, eosinophilia, hepatomegaly, wheezing, pneumonia, splenomegaly
10-15 y.o.: ocular larva migrans- retinal lesions that appear as solid tumors near macula (can cause blindness)

Question 28

Diagnosing and treating Toxocariasis

Answer 28

Dx: clinical picture + serology
Tx: self-limited or albendazole for acute

Question 29

Typical clinical vignette for Toxocariasis

Answer 29

kid in sandbox with dogs

Question 30

Source and pathogenesis for Anisalkis simplex

Answer 30

tissue nematodes
source: ingestion of raw or undercooked seafood (worldwide but many cases in Japan and Spain)
Inhabits stomach of final host. The parasite will bury head in gastric mucosa causing intra-abdominal abscess. Worm eventually dies.

Question 31

Symptoms and treatment for Anisakis simplex

Answer 31

Sx: Pain, vomiting, allergic rxn (urticaria, itchy throat, anaphylactic shock)
Tx: endoscopic removal

Question 32

Pathogenesis and risk factors for getting schistosomiasis

Answer 32

Trematodes (flat flukes)
risk: swimming in feces water
snail– free worms – penetrate human skin– blood– liver –eggs in bowel/bladder
migrates against venous blood flow to liver

patho: granulomas (eggs and eosinophils) → fibrosis of liver and urinary tract → obstruction and portal HTN

Question 33

Symptoms for Schistosomiasis

Answer 33

sx: swimmer’s itch, portal htn, liver problems, hematuria, squamous cell carcinoma of bladder

Question 34

Histology and treatment for Schistosomiasis

Answer 34

histo: eggs in stool: spines look different: mansoni =large lateral spine; japonicum= small lateral spine; haematobium= large terminal spine
tx: praziquantel

Question 35

Discuss the presentation and treatment of Taenia solium if obtained from infected meat

Answer 35

source: worm infected meat (pig) worm has hooks unlike saginata (beef tapeworm)
dz: taeniasis- GI sx; attaches to intestinal wall, consumes food ingested by host, eggs are then passed in feces
tx: praziquantel

Question 36

If Taenia solium is obtained from eggs in feces water, how does it present? How do we treat it?

Answer 36

dz: eggs hatch in intestines, penetrate intestinal wall and travel to other tissue: cysticercosis- cysts in skin and neurocysticercosis- cysts in brain = sz and hydrocephalus
patho: hooklets attach to GI tract → auto-reproduce–> brain/muscle/skin
tx: albendazole

Question 37

How do we get Echinococcus granulosis and what is it?

Answer 37

cestodes (tapeworms)

source: dogs through feces; sheep are intermediate host

Question 38

Symptoms of tape worm

Answer 38

sx: echinococcal cyst in liver (also lung, brain, bones) with egg shell calcifications
cyst rupture may have anaphylactic rxn and acute abdomen

Question 39

How do we diagnose and treat tapeworm?

Answer 39

dx: imaging
tx: albendazole