A 48-year-old man comes to the emergency department due to the sudden onset of nausea, vomiting, and cramping abdominal pain. The patient has also had 2 episodes of watery diarrhea. The symptoms began 4 hours after eating at a buffet restaurant, and his sister, who had the same food, experienced similar symptoms. The patient was recently diagnosed with hemochromatosis and is receiving periodic phlebotomy.
Vital signs are within normal limits with no orthostatic changes. The abdomen is soft with mild, generalized tenderness. There is no guarding, rebound tenderness, or hepatosplenomegaly. Bowel sounds are increased.
Laboratory results are as follows:
Which of the following is the most likely causative organism of this patient's current illness?

Question

A 48-year-old man comes to the emergency department due to the sudden onset of nausea, vomiting, and cramping abdominal pain.  The patient has also had 2 episodes of watery diarrhea.  The symptoms began 4 hours after eating at a buffet restaurant, and his sister, who had the same food, experienced similar symptoms.  The patient was recently diagnosed with hemochromatosis and is receiving periodic phlebotomy.
Vital signs are within normal limits with no orthostatic changes.  The abdomen is soft with mild, generalized tenderness.  There is no guarding, rebound tenderness, or hepatosplenomegaly.  Bowel sounds are increased.
Laboratory results are as follows:
 Which of the following is the most likely causative organism of this patient's current illness?

Quizplus · Accepted Answer

11ec193a_964d_a0a3_853d_bf5785612950_MD0002_00 This patient and his sister developed similar gastrointestinal symptoms a few hours after consuming food at a buffet restaurant, raising strong suspicion for a foodborne illness. Nearly 50 million cases of foodborne illness occur in the United States annually. Although the underlying pathogen is rarely isolated, the organism can often be assumed based on presenting symptoms, type of food ingested, and the time interval from eating to symptom onset. Vomiting-predominant cases are commonly due to Staphylococcus aureus or Bacillus cereus enterotoxins, which are formed prior to ingestion and lead to rapid-onset (within 1-6 hours) illness. Manifestations primarily include abdominal cramps and vomiting, but fever and/or diarrhea can occasionally occur. (Choice A) Campylobacter jejuni is a common cause of diarrhea; symptom onset typically occurs 2-5 days (rather than hours) after ingestion and includes frequent small-volume diarrhea that often (but not always) has blood or mucus. Only about 20% of patients develop vomiting. Many cases are linked to contaminated poultry. (Choice B) Foodborne illness due to Clostridium perfringens is also toxin-mediated, so onset is relatively quick (<24 hours). However, this pathogen causes a watery diarrhea-predominant illness; vomiting is rare. (Choice C) Enterotoxigenic Escherichia coli (ETEC) causes a diarrhea-predominant illness that usually begins >24 hours after ingestion. ETEC is one of the most common causes of traveler's diarrhea. (Choice E) Vibrio parahemolyticus typically causes a diarrhea-predominant illness and is usually linked to the consumption of raw shellfish. Educational objective: Staphylococcus aureus and Bacillus cereus enterotoxins are common causes of vomiting-predominant, foodborne illness. Symptoms tend to arise rapidly, usually within 1-6 hours of ingestion. Abdominal cramps and vomiting are the primary features, but fever or diarrhea can occasionally occur. __________ References: Diagnosis and management of foodborne illness. (http://www.ncbi.nlm.nih.gov/pubmed/11214980) Staphylococcal enterotoxins. (http://www.ncbi.nlm.nih.gov/pubmed/11028954)

A 48-Year-Old Man Comes to the Emergency Department Due to the Sudden