Helminths and ectoparasites Flashcards
Nematodes ingested
“EAT”
Enterobius vermicularis
Ascaris lumbricoides
Trichinella spiralis
Nematodes through skin
“SANd”
Stronygloides
Ancylostoma
Necator
Cestodes “tapeworms”
Taenia solium
Diphyllobothrium latum
Echinococcus granulosus
Trematodes “flukes”
Schistosoma
Paragonimus westermani
Clonorchis sinensis
Nematode not GI involved
Wuchereria bancrofti
Ectoparasites
Lice, scabies, bedbugs
Enterobius vermicularis
Pin worm
Female worm lays eggs at anus -> anal pruritis
Dx: scotch tape test
Benzimidazoles: albendazole, mebendazole
pyrantel pamoate
Ascaris lumbricoides
Round worm
Eggs released into stool – 200K /day
Ingested eggs hatch in intestine
Released larvae penetrate bowel, travel to lungs
Larvae migrate up trachea to oropharynx -> swallowed
Worms mature in intestine -> eggs released in stool
Causes Loffler eosinophilic pneumonitis
-dyspnea
tx: Benzimidazole: mebendazole, albendazole
pyrantel pamoate
Trichinella spiralis
Undercooked meat – pork, wild game
Larvae migrate from GI to muscles Myositis Fever Eosinophilia Periorbital edema
Tx: benzimidazole
Strongyloides stercoralis
Larvae in soil penetrate skin of feet -> enter blood stream -> lung -> swallowed -> GI tract
Tx: ivermectin, albendazole
Ancylostoma and Necator
Hook worms
Penetrate skin of feet -> vasculature -> lungs -> oropharynx -> intestines
Hook into intestinal wall and suck blood
Abdominal discomfort, anemia
Tx: benzimidazoles: albendazole, mebendazole
Pyrantel pamoate
Taenia solium
“pork tapeworm”
ingestion of larvae in undercooked pork
-GI tract infection by adult worm
-2-8 m long, lives 10-20 yrs
ingest eggs in contaminated food or water
- > larval infection: cysticercosis: muscles, brain (swiss cheese)
- immigrant w/ new seizure or CNS and psych problems
Tx:Albendazole, praziquantel, dexamethasone (protect CNS from worse sx from dying larvae)
Diphyllobothrium latum
“fish tapeworm”
larvae ingested in raw fish
-> B12 deficiency -> megaloblastic anemia
tx: praziquantel
Echinococcus granulosus
“dog tapeworm”
transmitted through dog feces
eggs hatch in intestines -> larval cysts in parenchyma
cysts in liver, lungs can leak fluid -> anaphylaxis
tx: surgery
Schistosoma
“blood fluke”
eggs released -> larvae mature in freshwater snails -> cercaria penetrate skin -> swimmers itch
migrate to lungs or liver to mature
- Mesenteric vessels – S. mansoni
- Lower urinary tract – S. haematobium
Can cause portal htn and splenomegaly w/ obstruction of portal v.
S. haematobium assoc w/ squamous cell carcinoma of bladder
-Egyptian w/ hematuria
Tx: praziquantel
