October 25, 2010

Q&A: Diagnostic Assessment Of Seafood Poisoning

As world travel and trade grow, physicians are increasingly likely to encounter patients poisoned by marine toxins. The world's oceans harbor hundreds of different types of marine toxins, and the epidemiology and clinical manifestations of these toxins vary widely. Several of these toxins are produced by dinoflagellates or phytoplankton during algae or marine diatom blooms. Shellfish and pufferfish poisoning arise from consumption of seafood that is contaminated by various toxins

This article is for Medical Students & Professionals
This is a Question & Answer revision article designed for medical students and professionals preparing for the PLAB, MRCP or USMLE examinations. They are based on actual questions from these examinations. You may find the Diarrhoea article more useful, or one of our many articles on Diseases & Conditions, Medical Syndromes, Health & Wellness or Home Remedies.
In this article:
Food poisoning
MCQ: clinical scenario
MCQ: answer
MCQ: explanation

Food poisoning

Shellfish and pufferfish poisoning arise from consumption of seafood that is contaminated by various toxins. In most instances the ingested seafood smells, appears, and tastes normal. Clinical features of the most common forms of shellfish or pufferfish poisoning typically develop within minutes to hours of ingestion. A food history that identifies ingestion of seafood commonly associated with the specific toxin, clinical features consistent with the specific poisoning, and detection of elevated levels of the toxin in the ingested seafood provides the diagnosis. Treatment is supportive.

MCQ: clinical scenario

A 40yr old man visiting a coastal area had sea food for dinner consisting of oyster and shrimps. Next morning he developed severe abdominal pain, diarrhea, vomiting and fever. The stools were blood stained. The man did not require any rehydration therapy and was treated with Ciprofloxacillin and recovered in about 2 days.

These clinical features are typical of infection by:

a) Vibrio cholerae
b) Vibrio parahaemolyticus
c) Vibrio vulnificus
d) Salmonella typhi
e) Rota virus

MCQ questions & answers on medicalnotes.info

MCQ: answer

The correct answer is B

MCQ: explanation

Vibrio parahaemolyticus is an important cause of gastroenteritis and food poisoning world wide. The gastroenteritis due to this organism is specifically and characteristically associated with the intake of sea food especially shrimps and oysters. It causes an acute diarrheal disease within 24hrs of ingestion of the infected food. The patient develops severe abdominal pain, diarrhea, vomiting and fever. The stools in a severe infection may be blood stained. The disease is more or less self limiting and is cured within 1-3 days.

Vibrio cholerae is incorrect since it causes a very severe gastroenteritis which has characteristically rice water stools and not blood stained stools. Also it has no association with consumption of sea food. The patient is severely dehydrated and if not rehydrated can die within hours.

Vibrio vulnificus also causes an infection after consumption of sea food but it is not the correct answer since it does not typically cause any gastrointestinal manifestations. The organism is absorbed quickly and causes a fatal septicemia.

Salmonella typhi does not typically cause an acute diarrheal disease. It does not manifest within 24hrs and has an incubation period of 7-14 days. Also it is a systemic infection and does not cause any gastrointestinal manifestations.

Rota virus causes mild diarrhea, usually in infants and children. It rarely infects adults. Also the diarrhea is very mild associated with little or no abdominal pain and rarely fever. It has no definite association with sea food

1). UpToDate: Overview of shellfish and pufferfish poisoning. Available online: https://www.uptodate.com/contents/overview-of-shellfish-and-pufferfish-poisoning

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