Trematodes — MCQs
Which Schistosoma species is primarily associated with eggs being discharged in urine?
A 52-year-old recent immigrant from Vietnam presents with abdominal swelling, weight loss, and upper abdominal pain of three weeks' duration. His past medical history includes malaria and infection with Clonorchis sinensis. On palpation, the liver is hard. An abdominal CT scan reveals a hypo-attenuated mass with lobulated margins in the liver, and a biopsy shows well-differentiated neoplastic glands embedded in a dense fibrous stroma. What is the most likely diagnosis?
Which of the following statements about trematodes is true?
Painless terminal hematuria is seen as one of the manifestations in the infection caused by ?
An Egyptian fisherman develops lower abdominal pain and pain on urination, and reports seeing blood in his urine. Which of the following parasites is the most likely cause of urinary symptoms in this patient?
A 36-year-old male patient complaining of cough, cold, fever, and rusty sputum, with a history of travel to China and consumption of crab. Name the infection.
A man on return from East Asia complains of pain in abdomen, jaundice, with increased alkaline phosphatase and conjugated hyperbilirubinemia. Ultrasound shows blockage in the biliary tree. What could be the cause?
Cercariae are the infective form of which of the following parasites?
The following organism is called:
A 35 year old man presented with dry cough and rusty colored sputum. He has a history of eating in a Chinese restaurant very often with consumption of crabs. What is the probable causative agent in this condition?
Trematodes Indian Medical PG Practice Questions and MCQs
Question 1: Which Schistosoma species is primarily associated with eggs being discharged in urine?
- A. S. haematobium (Correct Answer)
- B. S. japonicum
- C. S. mansoni
- D. S. mekongi
Explanation: ***S. haematobium*** - *S. haematobium* specifically targets the **urinary bladder plexus**, leading to the discharge of eggs in the **urine**. - Infection with *S. haematobium* is the primary cause of **urinary schistosomiasis** and is associated with complications like **hematuria** and bladder cancer. *S. japonicum (intestinal)* - *S. japonicum* primarily infects the **mesenteric veins of the small intestine** and discharges its eggs in **feces**, not urine. - This species is known for causing severe **intestinal and hepatic schistosomiasis** due to the large number of eggs produced. *S. mansoni (intestinal)* - *S. mansoni* also primarily infects the **mesenteric veins, mainly of the large intestine**, and its eggs are excreted in **feces**. - It is a common cause of **intestinal schistosomiasis**, leading to symptoms such as abdominal pain, diarrhea, and hepatosplenomegaly. *S. mekongi* - *S. mekongi* is another **intestinal schistosome**, closely related to *S. japonicum*, and its eggs are discharged in **feces**. - This species is found in specific regions of Southeast Asia and causes similar symptoms to other intestinal schistosomes.
Question 2: A 52-year-old recent immigrant from Vietnam presents with abdominal swelling, weight loss, and upper abdominal pain of three weeks' duration. His past medical history includes malaria and infection with Clonorchis sinensis. On palpation, the liver is hard. An abdominal CT scan reveals a hypo-attenuated mass with lobulated margins in the liver, and a biopsy shows well-differentiated neoplastic glands embedded in a dense fibrous stroma. What is the most likely diagnosis?
- A. Cholangiocarcinoma (Correct Answer)
- B. Gallbladder carcinoma
- C. Angiosarcoma
- D. Hepatic adenoma
Explanation: ***Cholangiocarcinoma*** - The history of **Clonorchis sinensis** infection is a significant risk factor for the development of cholangiocarcinoma, a malignancy of the bile ducts [1]. - The presentation of a **hypo-attenuated mass** with well-differentiated glands in the biopsy is characteristic of cholangiocarcinoma, especially given the patient's background. [1] *Carcinoma of the gallbladder* - Typically presents with mass lesions, but would more likely show **gallbladder wall thickening** rather than a hypo-attenuated mass in the liver. - Associated with **gallstones** and chronic inflammation, which are not indicated in this patient's history. *Hemangiosarcoma* - More commonly found in the spleen or heart; liver involvement is rare. - Biopsy would show **vascular spaces** rather than well-differentiated neoplastic glands, making it less likely in this case. *Hepatocellular carcinoma* - Generally develops in patients with **chronic liver disease** and shows a more **vascular** appearance on imaging [2]. - The biopsy findings of well-differentiated glands and the absence of cirrhotic liver history point away from hepatocellular carcinoma.
Question 3: Which of the following statements about trematodes is true?
- A. Segmented
- B. Anus present
- C. Body cavity present
- D. Two hosts required (Correct Answer)
Explanation: ***Two hosts required (Correct)*** - Trematodes typically require at least **two hosts** to complete their life cycle: an intermediate host (usually a **snail**) and a definitive host (a vertebrate). - This complex lifecycle involving multiple hosts is a characteristic feature of **flukes**. - This is a fundamental distinguishing feature that separates trematodes from some other helminths. *Segmented (Incorrect)* - Trematodes (flukes) have **unsegmented, leaf-shaped or cylindrical bodies**, unlike cestodes (tapeworms) which are segmented. - The absence of body segmentation is a key morphological distinction from other helminths. *Anus present (Incorrect)* - Trematodes have an **incomplete digestive system** with a mouth and an esophagus, but **no anus**. - Waste products are expelled back through the **mouth**. - This blind-ending gut is characteristic of the class Trematoda. *Body cavity present (Incorrect)* - Trematodes are **acoelomates**, meaning they lack a true fluid-filled body cavity (coelom). - Their internal organs are embedded in **parenchymatous tissue** filling the space between body wall and organs.
Question 4: Painless terminal hematuria is seen as one of the manifestations in the infection caused by ?
- A. Plasmodium falciparum
- B. Schistosoma japonicum
- C. Schistosoma haematobium (Correct Answer)
- D. Schistosoma mansoni
Explanation: ***Schistosoma haematobium*** - *Schistosoma haematobium* characteristically infects the **urinary bladder**, leading to inflammation and ulceration of the bladder wall [1]. - This irritation often manifests as **painless terminal hematuria**, which is the passage of blood at the end of micturition without associated pain [1]. *Plasmodium falciparum* - *Plasmodium falciparum* is the causative agent of **malaria**, a parasitic infection that primarily affects red blood cells and the liver. - While it can cause severe systemic symptoms, **hematuria** is not a typical or distinguishing feature of *P. falciparum* infection; rather, it often presents with fever, chills, and organ damage. *Schistosoma japonicum* - *Schistosoma japonicum* primarily infects the **mesenteric veins** of the small intestine, leading to intestinal and hepatic schistosomiasis [1]. - Symptoms are usually gastrointestinal (e.g., abdominal pain, diarrhea) or hepatic (e.g., hepatosplenomegaly), with **urinary tract involvement** and hematuria being highly uncommon [1]. *Schistosoma mansoni* - *Schistosoma mansoni* mainly infects the **mesenteric veins** of the large intestine, causing intestinal schistosomiasis. - Its clinical manifestations typically include **abdominal pain**, bloody diarrhea, and liver fibrosis, but not urinary symptoms like **hematuria**.
Question 5: An Egyptian fisherman develops lower abdominal pain and pain on urination, and reports seeing blood in his urine. Which of the following parasites is the most likely cause of urinary symptoms in this patient?
- A. Clonorchis sinensis
- B. Schistosoma haematobium (Correct Answer)
- C. Fasciola hepatica
- D. Diphyllobothrium latum
Explanation: ***Schistosoma haematobium*** - The patient's presentation with **lower abdominal pain**, **dysuria**, and **hematuria** is highly characteristic of urinary schistosomiasis, caused by *Schistosoma haematobium*. - The patient's origin as an **Egyptian fisherman** places him in an **endemic area** where contact with contaminated fresh water containing the parasite's larval forms (cercariae) is common. *Clonorchis sinensis* - This parasite causes **clonorchiasis**, an infection primarily affecting the **biliary tract** and liver, leading to symptoms like cholangitis, cholecystitis, and hepatomegaly. - It is typically acquired by consuming **raw or undercooked freshwater fish**, but does not cause urinary symptoms. *Fasciola hepatica* - *Fasciola hepatica* causes **fascioliasis**, a **liver fluke infection** that primarily affects the **biliary ducts** leading to symptoms like right upper quadrant pain, fever, and jaundice. - It is acquired by ingesting **metacercariae on aquatic plants**, particularly watercress, and does not cause urinary manifestations. *Diphyllobothrium latum* - This is the **fish tapeworm**, which causes **diphyllobothriasis**, an intestinal infection. - Symptoms are usually mild or asymptomatic, but can include abdominal discomfort, nausea, and notably **vitamin B12 deficiency** leading to megaloblastic anemia, not urinary symptoms.
Question 6: A 36-year-old male patient complaining of cough, cold, fever, and rusty sputum, with a history of travel to China and consumption of crab. Name the infection.
- A. Paragonimus westermani (Correct Answer)
- B. Fasciola hepatica
- C. Fasciolopsis buski
- D. Entamoeba histolytica
Explanation: ***Paragonimus westermani*** - This patient's symptoms of **cough**, **fever**, and **rusty sputum**, combined with a history of **travel to China** and consumption of **crab**, are highly suggestive of **paragonimiasis**. - *Paragonimus westermani* is a **lung fluke** endemic to East Asia, and its larvae are acquired by ingesting undercooked **crabs** or **crayfish**. *Fasciola hepatica* - *Fasciola hepatica* causes **fascioliasis**, primarily affecting the **liver** and **biliary ducts**, leading to symptoms like **fever**, **abdominal pain**, and **hepatomegaly**. - It is acquired by consuming **contaminated watercress** or other aquatic plants, not crabs. *Fasciolopsis buski* - *Fasciolopsis buski* causes **fasciolopsiasis**, an **intestinal fluke infection** presenting with **abdominal pain**, **diarrhea**, and **malabsorption**. - It is transmitted through ingestion of **contaminated aquatic plants**, and does not typically cause respiratory symptoms or "rusty sputum." *Entamoeba histolytica* - *Entamoeba histolytica* is a **protozoan** that causes **amoebiasis**, primarily presenting as **dysentery** or **amoebic liver abscess**. - While it can manifest as fever and liver involvement, it does not cause respiratory symptoms like "rusty sputum" and is not acquired from crabs.
Question 7: A man on return from East Asia complains of pain in abdomen, jaundice, with increased alkaline phosphatase and conjugated hyperbilirubinemia. Ultrasound shows blockage in the biliary tree. What could be the cause?
- A. Strongyloides
- B. Clonorchis sinensis (Correct Answer)
- C. Fasciola buski
- D. Ancylostoma
Explanation: ***Clonorchis sinensis*** - This parasitic fluke, common in East Asia, infects the **biliary ducts**, causing **cholangitis**, obstruction, and the symptoms described. - The combination of travel history, abdominal pain, jaundice, increased alkaline phosphatase, and conjugated hyperbilirubinemia, along with a blocked biliary tree on ultrasound, is highly suggestive of **clonorchiasis**. *Strongyloides* - This nematode primarily infects the **small intestine** and can cause abdominal pain, diarrhea, and malabsorption. - It does not typically cause biliary obstruction with jaundice and increased alkaline phosphatase. *Fasciola buski* - This fluke primarily infects the **small intestine** and causes symptoms like abdominal pain, diarrhea, and malabsorption, similar to Strongyloides. - While other Fasciola species (e.g., *F. hepatica*) can affect the biliary tree, *F. buski* is not known for causing biliary obstruction leading to jaundice. *Ancylostoma* - This hookworm primarily causes **iron-deficiency anemia** due to chronic blood loss in the intestines. - It does not typically cause symptoms related to biliary obstruction or jaundice.
Question 8: Cercariae are the infective form of which of the following parasites?
- A. Schistosoma hematobium (Correct Answer)
- B. Paragonimus westermani
- C. Fasciola hepatica
- D. Taenia solium
Explanation: ***Schistosoma hematobium*** - **Cercariae** are the motile, free-swimming larval stage of **Schistosoma** species, including *S. hematobium* - They **actively penetrate human skin** to initiate infection, making cercariae the infective form for humans *Paragonimus westermani* - The infective form for humans is **metacercariae**, which are ingested by consuming insufficiently cooked **crabs or crayfish** - Cercariae develop into metacercariae in secondary intermediate hosts (crustaceans) *Fasciola hepatica* - Humans are infected by ingesting **metacercariae** present on aquatic vegetation, such as **watercress** - Cercariae encyst on plants to form metacercariae, not directly infective *Taenia solium* - The infective forms are **cysticerci** in undercooked pork (for adult tapeworm) or **embryonated eggs** (causing cysticercosis) - This cestode has a different life cycle and does **not** involve cercariae
Question 9: The following organism is called:
- A. Cestode (Correct Answer)
- B. Nematode
- C. Trematode
- D. Annelid
Explanation: ***Cestode*** - The image displays a long, **segmented, ribbon-like worm**, which is characteristic morphology of a **tapeworm (cestode)**. - Cestodes typically possess a head (scolex) for attachment and a body composed of repeating segments called **proglottids**. *Nematode* - **Nematodes** are generally **unsegmented**, cylindrical, and elongated worms, often described as roundworms. - They lack the distinct proglottids and flattened, ribbon-like appearance seen in the image. *Trematode* - **Trematodes**, also known as flukes, are typically **leaf-shaped** and **unsegmented**. - They are much broader and flatter than the organism shown, and do not have the visible segmentation. *Annelid* - **Annelids** are segmented worms like earthworms and leeches, but they have a **cylindrical body** with visible external ring-like segments. - Unlike cestodes, annelids have a complete digestive system and lack the flat, ribbon-like morphology and internal proglottid structure characteristic of tapeworms.
Question 10: A 35 year old man presented with dry cough and rusty colored sputum. He has a history of eating in a Chinese restaurant very often with consumption of crabs. What is the probable causative agent in this condition?
- A. Pneumocystis jirovecii
- B. Paragonimus westermani (Correct Answer)
- C. Strongyloides stercoralis
- D. Diphyllobothrium latum
Explanation: ***Paragonimus westermani*** - The key clinical features are **dry cough**, **rusty-colored sputum**, and a history of consuming **crabs**. These are classic indicators of **paragonimiasis**. - *Paragonimus westermani* is a **lung fluke** acquired by eating undercooked freshwater crabs or crayfish. *Pneumocystis jirovecii* - This fungus typically causes pneumonia in **immunocompromised individuals**, like those with HIV/AIDS. - While it can cause a dry cough, **rusty-colored sputum** is not a characteristic sign, and there's no mention of immunocompromise. *Strongyloides stercoralis* - This parasite primarily causes **gastrointestinal symptoms** (e.g., abdominal pain, diarrhea) and can lead to cutaneous manifestations (larva currens). - While lung involvement can occur in severe cases (hyperinfection), it does not typically present with **rusty sputum** or a direct association with crab consumption. *Diphyllobothrium latum* - This is the **fish tapeworm**, acquired by eating undercooked freshwater fish. - It primarily causes **gastrointestinal symptoms** such as abdominal pain and diarrhea, and is known for causing **vitamin B12 deficiency** leading to megaloblastic anemia, not pulmonary symptoms.
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