Diarrhea Case 3

A 25-year-old woman is hospitalized for multiple injuries to her arms and legs from an automobile accident. She is treated with several intravenous broad-spectrum antibiotics because of significant concern that her wounds are becoming infected with a mixed flora of organisms. She responds over the next several days to the antibiotics with an initial decrease in fever. However, on the fourth day after her accident, she develops severe diarrhea with fever, vomiting, cramping abdominal pain, tenesmus, abdominal distension, and fluid losses severe enough to require IV fluids.

Q1

Proctoscopic examination demonstrates discrete yellow plaques up to 2 cm diameter which are scattered over the colonic mucosa. Which of the following would most likely be demonstrated on colonic biopsy?

/ A. Acid fast bacteria

/ B. Neoplastic polyps

/ C. Parasitic eggs

/ D. Pseudomembrane formation

/ E. Small granulomas

Q2

Which of the following organisms has been implicated in this disease?

/ A. Clostridium botulinum

/ B. Clostridium difficile

/ C. Clostridium perfringens

/ D. Clostridium septicum

/ E. Clostridium tetani

Q 3

Which of the following tests would be most helpful in confirming the diagnosis?

/ A. CT scan

/ B. MRI scan

/ C. "Scotch tape" test

/ D. Specific toxin in stool

/ E. Stool for ova and parasites

Q 4

This patient should not undergo barium contrast studies because of the increased risk in her disease of which of the following

/ A. AIIergic reaction

/ B. Gut perforation

/ C. Predisposition for cancerous transformation

/ D. Secondary appendicitis

/ E. Trapping of dye in diverticula

Q 5

Which of the following drugs is most likely to be effective in this case?

/ A. 3rd generation cephalosporin

/ B. Amoxicillin

/ C. Ampicillin

/ D. CIindamycin

/ E. Vancomycin

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Diarrhea Case 3 Answers

A1

The correct answer is D. This patient's history and proctoscopic examination are typical of severe pseudomembranous colitis (also sometimes called antibiotic associated colitis). Patients with milder disease may have only diarrhea. On pathologic examination, pseudomembranes composed of fibrin, neutrophils, necrotic material, and bacteria are seen overlying partially disrupted glands with prominent submucosal edema.

Acid fast bacteria (choice A) would suggest tuberculosis or atypical mycobacterial infection.

Neoplastic polyps (choice B) are seen as isolated findings or as part of familial polyposis syndromes.

Pseudomembranous colitis is not related to parasitic infection (choice C).

Small granulomas (choice E) could suggest either Crohn disease or tuberculosis.

A2

The correct answer is B. The clostridia are gram-positive, anaerobic, spore-forming rods that can produce a variety of nasty diseases. This patient's disease, pseudomembranous colitis, is due to bacterial gut overgrowth with Clostridium difficile, usually in the aftermath of broad-spectrum antibiotic therapy. Both children and adults may become infected. Probably in most cases, the patients already had small numbers of the organisms in their guts before antibiotic therapy, although isolated examples of transmission within wards have also been documented.

Clostridium botulinum(choice A) causes botulism.

Clostridium perfringens(choice C) and Clostridium septicum(choice D) cause gas gangrene.

Clostridium tetani(choice E) causes tetanus.

A3

The correct answer is D. Clostridium difficile produces toxins A and B, which can now be rapidly identified in stool samples. This is the best confirmatory test following proctoscopy, as the results will be back much faster than the pathology report on a tissue sample. The toxins cause necrosis of the superficial gut mucosa that, in turn, leads to pseudomembrane formation. True infection of the gut wall by the bacteria does not occur. (The bacteria like to live in and eat the necrotic material and fibrin of the pseudomembrane.)

CT scan (choice A) and MRI scan (choice B) are expensive tests that will not contribute to the diagnosis.

The "Scotch tape" test (choice C) involves using tape to collect pinworm eggs from the perirectal skin.

Clostridium difficile is a bacterium rather than a larger parasite, so stool for ova and parasites (choice E) would not be helpful.

A4

The correct answer is B. In addition to the immediate risks related to hypotension, dehydration, and electrolyte imbalance in these sometimes critically ill patients, complications that can incur include colonic perforation (which may be induced by barium contrast studies) and toxic megacolon.

Pseudomembranous colitis does not alter allergic reactions (choice A), predispose for appendicitis (choice D) or cancer (choice C), or induce formation of diverticula (choice E).

A5

The correct answer is E. Clostridium difficile is resistant to most antibiotics, which is why it tends to cause a bowel bacterial overgrowth when broad-spectrum antibiotics are used. The two antibiotics to which it is usually sensitive, and that are consequently most often used to treat pseudomembranous colitis, are vancomycin and metronidazole. The other agents listed in the choices are frequently reported causes of pseudomembranous colitis.

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Gastrointestinal Bleeding case 4

A 25-year-old man presents to the emergency department complaining of passing bright red blood per rectum. He reports no prior episodes of gastrointestinal bleeding, but he has had occasional lower abdominal pain and diarrhea for the past ten months. He reports a 7 kg weight Ioss since the onset of these symptoms. He denies sick contacts. On examination, he is febrile with moderate, diffuse abdominal pain to palpation and percussion. Rectal examination is positive for blood.

Q 1

Which of the following is the most likely diagnosis?

/ A. Chronic pancreatitis

/ B. Duodenal ulcer

/ C. Infectious colitis

/ D. Inflammatory bowel disease

/ E. Ischemic colitis

Q 2

A colonoscopy is performed and mucosal ulceration with bleeding extending continuously from the rectum to the cecum is seen. The terminal

ileum is spared. Had the terminal ileum been affected, the patient would have been at risk for which of the following conditions?

/ A. Diabetes mellitus

/ B. Folate deficiency

/ C. Iron deficiency anemia

/ D. Kwashiorkor

/ E. Pernicious anemia

Q 3

At colonoscopy the colonic mucosa appears granular, and is ulcerated. Numerous crypt abscesses and pseudopolyps are observed. Which of

the following is the most likely diagnosis?

/ A. Celiac disease

/ B. Clostridium difficile colitis

/ C. Crohn disease

/ D. Rectal diverticulosis

/ E. Ulcerative colitis

Q 4

Several months pass and this patient's symptoms progress. He continues to have frequent bloody diarrhea and abdominal pain. Abruptly, this

patient experiences the acute onset of severe abdominal pain and is taken to the emergency department by friends. In the emergency

department, he is febrile, and his abdomen is rigid, with severe pain to palpation and percussion. Laboratory findings are consistent with

dehydration. Amylase and lipase are normaI. Which of the following most likely explains this patient's new findings?

/ A. Abdominal aortic aneurysm rupture

/ B. Acute pancreatitis

/ C. Bowel perforation and peritonitis

/ D. Sepsis from fulminant infectious colitis

/ E. Severe ischemic colitis

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Gastrointestinal Bleeding case 4 answers

A1

The correct answer is D. Patients with inflammatory bowel disease can present with a variety of symptoms. While ulcerative colitis and Crohn disease patients may have distinct presentations, mixed presentations are common. Distinguishing Crohn disease and ulcerative colitis is difficult, based on clinical findings. Symptoms typical for Crohn disease include: abdominal pain, fever, diarrhea, weight loss, and anal disease. Symptoms typical for ulcerative colitis include: bloody diarrhea, fever, and weight loss.

Chronic pancreatitis (choice A) presents as epigastric pain that radiates to the back, weight loss, and steatorrhea. In many cases, a history of alcoholism is present. Thus the location of this patient's pain and his lower GI bleeding are not consistent with chronic pancreatitis.

Duodenal ulcer (choice B) may present as epigastric pain, and with severe disease, severe bleeding may be present. Patients with duodenal ulcer rarely have diarrhea and weight loss. Thus this diagnosis is unlikely.

Infectious colitis (choice C) presents as abdominal pain and bleeding. Many infectious agents may cause GI bleeding, including Salmonella, Shigella, Campylobacter jejuni, and E. coli. The chronic nature of this patient's complaints and the lack of sick contacts suggests a different diagnosis.

Ischemic colitis (choice E) presents as acute onset of severe abdominal pain often with copious bright red blood per rectum. On examination, they display the classic finding of "pain out of proportion to examination." They are typically elderly patients with a history of atherosclerotic or embolic disease.

A2

The correct answer is E. Pernicious anemia is a hypochromic, megaloblastic anemia that may be associated with neurologic complications. It occurs as a result of a lack of vitamin B 12. The B12/intrinsic factor complex is absorbed in the terminal ileum by active transport. If this patient's ulcerative colitis extended into the terminal ileum, this condition could complicate his disease. Crohn disease almost invariably affects the terminal ileum, and this malabsorptive condition is more common in that setting. Ulcerative colitis usually affects only the colon, but ileal extension has been observed.

Diabetes mellitus (choice A) is an endocrine condition, and is unrelated to the absorptive capacity of the terminal ileum.

Folate (choice B) is absorbed in the proximal small intestine. Ileal involvement would not affect its absorption.

Iron (choice C) is also absorbed in the proximal small intestine. Ileal involvement would not affect its absorption.

Kwashiorkor (choice D) is protein malnutrition. Protein is absorbed throughout the small intestine. Ileal involvement would not affect its absorption.

A3

The correct answer is E. Granular, flat mucosa with ulcers, crypt abscesses, and pseudopolyps are characteristic findings in ulcerative colitis.

Celiac disease (choice A) is a disease of the intestine resulting from a hypersensitivity to the protein gluten. The intestinal mucosa is smooth and atrophic.

Clostridium difficile colitis (choice B) or "pseudomembranous colitis" is a colonic infection seen after extensive antibiotic use, which disturbs the colonic flora, promoting overgrowth of C. difficile. Fibrinous pseudomembranes are seen in the colon at colonoscopy.

Endoscopic evaluation of Crohn disease (choice C) reveals swollen mucosa with transverse fissures and linear ulcers. Biopsy findings demonstrate transmural involvement with granuloma formation.

Diverticula are outpouchings of the intestinal mucosa. They may bleed, or they may become infected, leading to a painful condition, diverticulitis. The findings here do not suggest diverticulosis (choice D).

A4

The correct answer is C. This patient's chronic course with acute exacerbation suggests that this patient has viscus perforation with peritonitis secondary to exacerbation of his ulcerative colitis. The inflammatory processes in ulcerative colitis can be so severe that erosion from inflammation can cause colonic perforation. Bowel contents then leak into the peritoneal cavity, causing peritonitis. Peritonitis is characterized by fever, severe abdominal pain, abdominal tenderness to palpation and percussion, and rigidity of the abdominal wall.

Abdominal aortic aneurysm rupture (choice A) presents as abdominal pain that radiates to the back. It is accompanied by hemodynamic instability that may deteriorate to shock. This presentation is not consistent with findings in this patient.

Acute pancreatitis (choice B) can cause severe abdominal pain and fever. The pain, however is usually epigastric and radiating to the back. Typically nausea and vomiting accompany pancreatitis. Amylase and lipase are elevated.

This patient does not display the symptoms of sepsis (choice D). In sepsis, patients are febrile with hemodynamic instability.

Ischemic colitis (choice E) can lead to perforation and peritonitis, and if the patient had symptomatology consistent with ischemic colitis, it could be the source of this patient's peritonitis. This patient did not report bright red blood per rectum, or "pain out of proportion to examination," making ischemic colitis less likely.