helminths - trematodes and cestodes Flashcards
Schistosomiasis
- caused by S mansoni, S. japonicum, S. haematobium, secondarily to malaria as a disabling dz
- LIVER, BLADDER (IRREV). lesion: circumscribed granulating cellular infiltrate (eosinophils and neutrophils around eggs)–> SELF-LIMITED INTENSELY PRURITIC RASH. if its an older–> giant cells and epitheloid macrophages. if much older–> densely fibrotic
- LIVER: periportal granulomatous infl –> dense peripheral fibrosis (PIPESTEM FIBROSIS) –> PORTAL HTN –> SPLENOMEGALY, ASCITES, ESOPHAGEAL VARICES
- UROGENITAL: eggs in bladder, ureter, seminal vesicles, may reach lungs, colon, appendix. causes granulomatous rx, and fibrosis. URINARY OBST–> infection –> CHRONIC CYSTITIS, can also cause bladder SCC (most common cancer where heamatobiumis present) and hematouria, recurrent UTIs, renal failure
- TX: antihelm
sch egg gets in water and becomes miracidium –> snail –> cercaria, cercaria looses tail and becomes schistasomula. if human steps on it –> blood to tissues to lungs to liver (intestine: mature, sex, eggs)
- S. mansoni and Japonicum: eggs deposit in intestinal venules –> matures as it travels from intestinal walls to feces
- S. trematobium: bladder veins –>eggs mature as it travels from bladder to urine
- eggs hatch in fresh water and releases miracidia, re-cycles
what are the 4 trematodes?
trematodes = flukes = flatworms
- Schistosomiasis
- Clonorchiasis
- paragonimiasis
- fascioliasis
clonorchiasis
- clonorchiasis/chinese liver fluke caused by clonorchis sinensis
- BILIARY OBST, STONE, CHOLANGITIS, pancreatic ducts may fibrosis, CANCER(cholangiocarcinoma)
- Cause: ingest fish with C. sinensis. similar to schistomiasis (cercariae infects humans) - duodenum –> ampula of Vater –> CBD –> mature into adults in the distal BILE DUCTS
-causes stroma to hyperplasia then metaplasia –> fibrotic. if there are eggs in liver –> FIBROUS AND GRANULOMATOUS RXN,
TX: antihelm
paragonimiasis
- paragonimiasis / lung fluke, caused by paragonimus westermani, asian countries, may be misdiagnosed as TB but diff in that paragon has eosinophilia
- ingestion of uncooked crabs
- SX: fever, malaise, night sweats, CP, cough with sputum sometimes tinged with blood
- CXR: DIFFUSE PUL INFILTRATES, if get to ectopic brain lesions –> fatal. if not, the prognosis is good.
fascioliasis
- caused by fasciola hepatica - sheep liver fluke, from vegetations such as watercress thats contaminated with cysts passed by sheep.
- BILIARY DZ from sheep: SX: ACUTE GASTRIC PAIN, EOSINOPHILIA, VOMITING. FATAL UNTX
- duodenum –> peritoneal cavity –> liver parenchyma –> bile ducts (intra and interhep bile ducts - fibrosis, BILIARY OBST). adults move back to liver and eat liver cells and deposit eggs –> liver abscess and granulomas
Fasciolopsiasis: caused by fasciolopsis buski intestinal fluke. aquatic vegs, intestines –> may ulcerate. pain like peptic ulcer, obst. Tx antihelm
what are the intestinal tapeworms (cestodes)?
- taeniasis and cysticercosis (taenia solium)
- cystic hydatid dz/echinococcosis (echinococcus granulosus)
- diphyllobothrium latum
taeniasis
-caused by T. solium (pork), T.saginata = beef
(animals get it from eating human feces)
T.latum = fish (areas raw fish common. takes up B12 –> pernicious anemia)
cystic larval stages in mm’s –> worm stages in humans
cysticercosis
caused by t. solium, fecal oral spread
- systemic infection caused by larvae of pork tapeworm
- infected humans feces (eggs)–> another human –> eggs relase oncospheres that go to gut wall and eventually go to tissues to encysts and develop into cysticerci (has scolex)
- cysts okay but can compress on adj tissue. degenerating cysts causes inflm (eosin, neutro, lymphocytes, plasma cells). if cysts in BRAIN: SWISS CHEESE. IF MASSIVE –> CONVULSIONS AND DEATH
-SX: headaches, SEIZURES, depends on brain structure; eyes - blind, hear - arrythemias and death
cystic hydratid dz
- cystic hydatid/echinococcosis caused by larval cestodes of echinococcus granulosus
- ZOONATIC INF: adult tapeworm lives in carnivorus SI –> feces –> grass. humans may ingest grass –> eggs get in blood and infect organs, organs grow LARGE CYSTS (slow growth) with brood capsules and scolices.
-hepatic cyst: RUQ mass –> compress ducts –> obst jaundice, if cyst ruptures –> severe diffuse pain, resembles PERITONITIS
-pul cyst: Asx, found on CXR accidentally. if rupture–>PNEUMOTHORAX, EMPYEMA
-if seed into adj tissues: MORE CYSTS -> PAIN LIKE PERITONITIS. if rupture: SEVERE ALLERGIC RXN
TX: careful surgery, cyst must be sterilized with formalin first before drainage or extirpation to prevent intraoperative anaphylactic shock
