DDSEP® 8 Quick Quiz

Question 1

Publish date: November 30, 2021

Q1. A 36-year-old man presents to the clinic with a history of diarrhea and significant fatigue for the last 2 months. He has no significant past medical history and works as a chef in a local sushi bar. He complains of six to seven watery stools daily with nocturnal symptoms. Diarrhea is associated with abdominal cramps, and he denies any passage of blood. His physical examination, including vital signs, is unremarkable. Laboratory investigation reveals 9.8 g/dL hemoglobin, with a mean corpuscular volume 110 fL. Peripheral eosinophilia is also noted. A stool sample is sent to the lab and is pending.

Which of the following is the most likely cause of this illness?

Diphyllobothrium latum

Hymenolepis diminuta

Hymenolepis nana

Taenia saginata

Taenia solium

Correct answer: A. Diphyllobothrium latum.

Rationale
This is likely a tapeworm infection with Diphyllobothrium latum. D. latum infection can be acquired from ingesting certain forms of freshwater fish, and those who consume raw fish, including sushi, are at increased risk. The classical manifestation of infection with D. latum is megaloblastic anemia due to vitamin B12 deficiency. D. latum has a unique affinity for vitamin B12 and therefore competes with the host for absorption. Humans become infected with Taenia by ingesting raw or undercooked infected meat containing cysticerci. Infection with Hymenolepis is common in children secondary to breaches in fecal-oral hygiene. Most infections are asymptomatic.

Reference
Webb C, Cabada MM. Curr Opin Infect Dis. 2017 Oct;30(5):504-10.

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