Tissue Invasive Nematodes Flashcards
How do we get Trichinella Spiralis?
Undercooked meat will give us this intestinal nematode
Discuss the pathology and symptoms of Trichinella Spiralis
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)
Discuss the lab values and how we diagnose Trichinella Spiralis
Labs: Eosinophilia
Dx: muscle biopsy (often insensitive); serology
Treatment for Trichinella Spiralis?
Tx:Albendazole (disrupts microtubules)
Discuss the pathology of Strongyloides stercoralis
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
How does Strongyloides present?
sx: diarrhea, bloating
Discuss the diagnosis and treatment for strongyloides
dx: larvae in stool
tx: Albendazole , ivermectin; steroids contraindicated
Pathology and presentation of Enterobius vermicularis
intestinal nematode: (pinworm)
enterobiasis
ingestion of pinworm eggs, by hands, food, or water
sx: itching in the anal area where eggs are lain
How to diagnose and treat enterobius vermicularis
dz: eggs on scotch-tape test
tx: Albendazole
What the hell is Angiostrongylius cantonensis? Where do we get it from?
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
Discuss the pathology and presentation of Angiostrongylius cantonensis
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
How do we diagnose and treat Angiostringylius cantonensis?
Dx: CSF eosinophilia + meningitis + exposure history
Tx: corticosteroids may help
Three presentation types of Filariasis
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
Discuss source and labs we see for filariasis in general
abs: blood eosinophilia, IgE elevation, and/ or filarial antibody titers
Source: spread by black flies (Simulium type) and mosquitoes.
Treatment of Filariasis
Tx: elevation, hygiene, foot care, cutaneous fungal infections/ bacterial infections
Discuss the source and location for Wuchereria
source: mosquito
lavae introduced to skin – invades lymphatics– blood
location: found in tropics
Discuss the disease progression of Wucheria bancrofti
Dz: Chronic Lymphatic filariasis → elephantiasis; also cough from filariasis in lungs
granulomas obstruct the lymphatic system → lymphedema
How do we diagnose and treat Wucheria bancrofti?
Dx: see microfilariae in nightime blood smear, or detection of antigen, or adult worm (biopsy or U/S)
tx: diethylcarbamazine (DEC)
Discuss the source and pathogenesis of onchocerca volvulus
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
Sympoms for onchocerca volvulus
dz: Subcutaneous filariasis and river blindness
sx: nodules under the skin, hyper/hypopigmented spots, severe itching, hanging groin, and blindness (begins as punctate keratitis)
Discuss the diagnosis and treatment for onchocerca volvulus
dx: microfilariae on microscopy of skin punch biopsy, serology, nodulectomy
tx: ivermectin
Discuss Loaloa
“african eyeworm” Vector: deer fly host: human only (no reservoir) blood borne microfilariae adult worms live in subcutaneous tissue found in Africa
Symptoms for Loa loa
Sx: may be asymptomatic, non-specific (fatigue, urticaria, arthralgia, myalgia)
subcutaneous angioedematous swelling (calabar swelling), eyeworm (does not cause blindness)
Diagnosis and treatment for Loa loa
Dx: ID adult worm in conjunctiva, microfilaria seen in noon blood smear, or clinical picture + antifilarial antibodies
Tx: DEC
What causes heartworm?
Dirofilaria Immitis (Heartworm)
What type of bug is Toxocariasis and how do we get it?
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
Symptoms of Toxocriasis
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)
Diagnosing and treating Toxocariasis
Dx: clinical picture + serology
Tx: self-limited or albendazole for acute
Typical clinical vignette for Toxocariasis
kid in sandbox with dogs
Source and pathogenesis for Anisalkis simplex
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.
Symptoms and treatment for Anisakis simplex
Sx: Pain, vomiting, allergic rxn (urticaria, itchy throat, anaphylactic shock)
Tx: endoscopic removal
Pathogenesis and risk factors for getting schistosomiasis
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
Symptoms for Schistosomiasis
sx: swimmer’s itch, portal htn, liver problems, hematuria, squamous cell carcinoma of bladder
Histology and treatment for Schistosomiasis
histo: eggs in stool: spines look different: mansoni =large lateral spine; japonicum= small lateral spine; haematobium= large terminal spine
tx: praziquantel
Discuss the presentation and treatment of Taenia solium if obtained from infected meat
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
If Taenia solium is obtained from eggs in feces water, how does it present? How do we treat it?
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
How do we get Echinococcus granulosis and what is it?
cestodes (tapeworms)
source: dogs through feces; sheep are intermediate host
Symptoms of tape worm
sx: echinococcal cyst in liver (also lung, brain, bones) with egg shell calcifications
cyst rupture may have anaphylactic rxn and acute abdomen
How do we diagnose and treat tapeworm?
dx: imaging
tx: albendazole
