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USMLE · Question #595

A 35-year-old male comes to the physician due to fatigue. He recently returned from a trip to Japan. Laboratory results are as follows: Hemoglobin " 9 g/dL - Mean corpuscular volume " 108 fl MCHC " 33

The correct answer is C. raw fish. Diphyllobothrium latum is a tapeworm which can cause vitamin B12 deficiency because it competes for this vitamin in the small intestine. Infection with this tapeworm occurs after consumption of raw or undercooked freshwater fish. Vitamin B12 deficiency may occur in infected patie

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Question

A 35-year-old male comes to the physician due to fatigue. He recently returned from a trip to Japan. Laboratory results are as follows:

Hemoglobin " 9 g/dL - Mean corpuscular volume " 108 fl MCHC " 33 g/dL - Mean corpuscular hemoglobin " 35 pg A peripheral blood smear is obtained which reveals enlarged red blood cells and hyper segmented neutrophils. If these findings were caused by an infection, the most likely source of the infection is via:

Options

  • Ablackfly bite
  • Bdog feces
  • Craw fish
  • Dsnails
  • Eundercooked pork

How the community answered

(46 responses)
  • A
    2% (1)
  • B
    13% (6)
  • C
    76% (35)
  • D
    2% (1)
  • E
    7% (3)

Explanation

Diphyllobothrium latum is a tapeworm which can cause vitamin B12 deficiency because it competes for this vitamin in the small intestine. Infection with this tapeworm occurs after consumption of raw or undercooked freshwater fish. Vitamin B12 deficiency may occur in infected patients and presents with fatigue due to the macrocytic megaloblastic anemia with hyper segmented neutrophils. Treatment of the infection is with praziquantel.

Topics

#Diphyllobothrium latum#megaloblastic anemia#B12 deficiency#helminth transmission

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