Lesson 3 - Trematodes Flashcards
Trematodes
Oriental fluke; Blood flukes.
Reside in the mesentric and portal veins.
Adult schistosomes exist as separate sexes (others are hermaphrodites)
Can cause schistosomiasis (aka bilharzias, bilharziasis, or snail fever).
Schistosoma japonicum / S. mansoni / S. haematobium
Snail: Oncomelania hupensis quadrasi
Schistosoma japonicum
Affects veins of small intestine, liver
Schistosoma japonicum
Diagnostic feature of eggs: Small lateral spine (‘knob’)
Schistosoma japonicum
Snail: Biomphlaria glabrata
S. mansoni
Affects veins of colon
S. mansoni
Diagnostic feature of eggs: Large, prominent lateral spine
S. mansoni
Snail: Bulinus truncatus
S. haematobium
Affects veins of Urinary Bladder
S. haematobium
Chronic Schistosomiasis:
Painless hematuria and fibrosis of the bladder. Hydronephrosis. Associated with squamous cell carcinoma of the bladder.
S. haematobium
Diagnostic feature of eggs: large terminal spine
S. haematobium
Intestinal Schistosomiasis
Acute schistosomiasis:
- Cercarial dermatitis (swimmer’s itch)
- Katayama fever
Schistosoma japonicum / S. mansoni / S. haematobium
Chronic Schistosomiasis:
- Pseudopolyps in colon
- Liver granulomas leading to presinusoidal obstruction, hepatomegaly, and portal hypertension.
- Gastrointestinal hemorrhage, massive splenomegaly
Schistosoma japonicum / S. mansoni
Liver UTZ: clay pipestem fibrosis with lacelike pattern.
MCC of death: exsanguination from ruptured esophageal varices.
Schistosoma japonicum / S. mansoni
Diagnostic Test:
- Fecalsys (kato-katz)
- Circumoval precipitin test (COPT)
- Rectal imprint
Schistosoma japonicum / S. mansoni / S. haematobium
Adult flukes living in mesentric or bladder veins la eggs that cause granulomas
Schistosoma japonicum / S. mansoni / S. haematobium
Japanese Lung fluke, Hermaphrodite
Paragonimus westermani
Snail: Antemelania asperata
Mountain crab: Sundathelphusa philippina
Paragonimus westermani
Infective stage - Larvae (metacercariae)
Transmitted by ingestion of raw crabmeat/crayfish
Paragonimus westermani
Affects the Lungs. Adult flukes live in the lungs.
Paragonimus westermani
Paragonimiasis
Within the lung, the worm exists in a fibrous capsule communicating with a bronchiole - granulomatous reaction. Secondary bacterial infection frequently occurs.
Paragonimus westermani
Main symptom: chronic cough with blood sputum
CXR: ring shadow opacity
Closely resembles tuberculosis
Paragonimus westermani
Diagnostic test: 3% NaOH preparation
Paragonimus westermani
Diagnostic feature of eggs: Operculated / unembryonated egg in sputum or feces
Paragonimus westermani
Chinese Liver fluke / Oriental liver fluke, Hermaphrodite
Clonorchis sinensis
Snail: Parafossarulus
Fish: Cyprinidae
Clonorchis sinensis
Infective stage: Larvae (metacercariae)
Transmitted by ingestion of undercooked fish.
Clonorchis sinensis
Affects the Liver, especially the common bile duct. Adult flukes live in the liver.
Clonorchis sinensis
Inflammatory response can cause hyperplasia and fibrosis of the biliary tract.
Clonorchis sinensis
Acute disease:
- Fever, eosinophilia, lymphadenopathy, tender hepatomegaly.
Chronic disease:
- Hepatobiliary disease
- Pancreatitis
- Cholangiocarcinoma (Klatskin tumor)
- Neurocirculatory dystonia
Clonorchis sinensis
Diagnostic Test:
- Direct fecal smear
- Potassium permanganate stain (showing melon-like ridges with abopercular protuberance)
Clonorchis sinensis
Treatment of Choice: PRAZIQUANTEL
Schistosoma japonicum, S. mansoni, S. haematobium, Paragonimus westermani, Clonorchis sinensis
Sheep liver fluke
- Humans are infected by eating watercress (or other aquatic plants)
- Symptoms are due primarily to the presence of the adult worm in the biliary tract.
Fasciola hepatica
In early infection, RUQ pain, fever, and hepatomegaly can occur but most infections are asymptomatic.
Months or years later, obstructive jaundice can occur.
Halzuon is a painful pharyngitis caused by the presence of adult flukes on the posterior pharyngeal wall.
Fasciola hepatica
Drug of choice is TRICLABENDAZOLE
Fasciola hepatica
Giant Intestinal fluke
Intestinal parasites of humans and pigs that is endemic to Asia and India. Humans are infected by eating aquatic vegetation that carries the cysts.
Pathologic findings are due to damage of the intestinal mucosa by the adult fluke.
Fasciola buski
Most infections are asymptomatic, but ulceration, abscess, formation, and hemorrhage can occur.
Worm intoxication: anasarca and coma resulting from accumulation of toxins.
Fasciolopsis buski
Intestinal parasite of people living in Africa, the Middle East, and Asia, who are infected by eating raw fish containing cysts.
Pathologic findings are due to inflammation of the intestinal epithelium as a result of the presence of the adult flukes.
Heterophyes heterophyes
Mimics peptic ulcer disease.
Heterophyes heterophyes
PRAZIQUANTEL is the treatment of choice.
Fasciolopsis buski / Heterophyes heterophyes
