A 47-year-old previously healthy man comes to the office due to 3 days of abdominal discomfort, nausea, and diarrhea. He has had 10-12 small-volume stools per day with no visible blood or mucus. He has had no fever or vomiting but did have generalized aches and a sense of being unwell prior to the onset of diarrhea. The patient has not taken any antibiotics or traveled recently. He ate at an outdoor cookout 2 days before he developed symptoms.
Vital signs are within normal limits with no orthostatic changes. Examination shows moist mucous membranes. Mild periumbilical tenderness is present with no guarding or rebound tenderness. Bowel sounds are increased. Rectal examination reveals no blood.
Which of the following is the most likely cause of this patient's symptoms?

Question

A 47-year-old previously healthy man comes to the office due to 3 days of abdominal discomfort, nausea, and diarrhea.  He has had 10-12 small-volume stools per day with no visible blood or mucus.  He has had no fever or vomiting but did have generalized aches and a sense of being unwell prior to the onset of diarrhea.  The patient has not taken any antibiotics or traveled recently.  He ate at an outdoor cookout 2 days before he developed symptoms.
Vital signs are within normal limits with no orthostatic changes.  Examination shows moist mucous membranes.  Mild periumbilical tenderness is present with no guarding or rebound tenderness.  Bowel sounds are increased.  Rectal examination reveals no blood.
Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec193a_9860_f09b_853d_e9c5f0bc81c3_MD0002_00 This patient who ate at an outdoor cookout developed frequent, small-volume stools several days later, raising strong suspicion for inflammatory diarrhea due to a foodborne illness. Inflammatory diarrhea is usually due to infection with Campylobacter, Shigella, or Salmonella. These pathogens invade the large bowel and result in abrupt-onset, crampy abdominal pain and frequent small-volume diarrhea several days after consumption. Blood and mucus are often (but not always) present in the stool. There may also be an associated febrile prodrome with nausea and vomiting. With the exception of enterohemorrhagic Escherichia coli (EHEC), most cases of inflammatory diarrhea are mild and self-limited. By contrast, noninflammatory diarrhea is usually due to the ingestion of enterotoxin-producing bacteria. Most cases affect the small bowel and lead to large-volume watery diarrhea with or without nausea, vomiting, abdominal cramps, and bloating. Fever is rarely present. Noninflammatory diarrhea is most commonly due to Clostridium perfringens and enterotoxigenic E coli (Choice B). (Choice C) Norovirus infection typically presents with headache, myalgias, acute-onset vomiting, and diarrhea (nonbloody with loose or watery stools). Symptoms usually resolve within 72 hours with full recovery. (Choice D) EHEC produces Shiga toxin and is typically transmitted by the consumption of undercooked ground beef. Manifestations include hemorrhagic colitis and, in 10%-15% of cases, hemolytic uremic syndrome. This patient had no blood in his stool or rectal vault, making EHEC less likely than Campylobacter. (Choice E) Staphylococcus aureus foodborne illness is due to the ingestion of preformed toxins and presents with sudden-onset nausea and vomiting 1-6 hours after consumption. Diarrhea and fever can occasionally occur. Educational objective: Inflammatory diarrhea usually originates in the large bowel and presents with small-volume, frequent diarrhea; possible febrile prodrome; and possible blood or mucus in the stool. Noninflammatory diarrhea originates in the small bowel and usually presents with large-volume, watery diarrhea. Organisms with preformed toxins typically cause sudden-onset nausea and vomiting 1-6 hours after ingestion without significant diarrhea. __________ References: Clinical features of sporadic Campylobacter infections in Norway. (http://www.ncbi.nlm.nih.gov/pubmed/1287808) Campylobacter enteritis: clinical and epidemiologic features. (http://www.ncbi.nlm.nih.gov/pubmed/380433)

A 47-Year-Old Previously Healthy Man Comes to the Office Due