General Surgery

Front 1

A 24-year-old man presents for evaluation of a 4-month history of postprandial diarrhea, weight loss of 9 pounds, and lower abdominal pain. He denies recent travel or antibiotic use. On physical examination, his temperature is 38.0 C (100.4 ), and he has several oral aphthous ulcers. On abdominal examination, there is tenderness and mild voluntary guarding in the right lower quadrant. A rectal examination reveals brown stool that is strongly guaiac positive. Which of the following is most likely causing this patient's symptoms?

Back 1

The correct answer is E. This patient, with postprandial diarrhea, weight loss, low-grade fever, and right lower quadrant findings on physical examination, has the typical presentation of Crohn disease, which most commonly involves the terminal ileum. Inflammation in this disease is transmural, as opposed to the inflammation in ulcerative colitis that is limited to the mucosa of the large intestine.

Although the etiology of Crohn disease is not known, gram-negative organisms (choice A) have not been demonstrated to be causative.

Folate deficiency (choice B) does not cause a diarrheal illness. It can, however, result infrequently from Crohn disease if there is severe proximal small bowel malabsorption.

Mucosal ulceration in the ascending colon (choice C) may be seen during a colonoscopy in patients with Crohn disease, but the inflammation in fact is transmural.

Toxin-producing organisms (choice D), such as enterotoxigenic Escherichia coli and Vibrio cholerae produce a watery diarrheal syndrome without any other of the findings described in this patient.

Hint 1

ileum

Front 2

A 19-year-old woman presents with a 2-week history of frequent episodes of loose stools. The symptoms are accompanied by severe fecal urgency, and she has awoken with diarrhea several nights weekly. Over the past week, the stools have become increasingly bloody. A sigmoidoscopy reveals continuous, symmetric inflammation from the anal verge to the proximal sigmoid colon. Which of the following infections is most likely causing this patient's symptoms?

A. Campylobacter jejuni
B. Cryptosporidium
C. Giardia lamblia
D. Herpes simplex
E. Yersinia enterocolitica

Back 2

The correct answer is A. This patient has an acute onset of bloody diarrhea consistent with colitis, which is confirmed with the sigmoidoscopy. Of the organisms listed, Campylobacter jejuni is the one most likely to cause these symptoms. This organism can cause diarrhea in all age groups, although the peak of incidence is in young children. C. jejuni can be acquired through exposure to contaminated food (especially undercooked poultry) or water, or through exposure to infected domestic or wild animals. The diarrhea can be either watery or bloody and is often accompanied by a sometimes high fever. White blood cells are commonly seen in the fecal material. You should also be aware that there appears to be an association between summer outbreaks of diarrheal disease due to this organism, and subsequent development of the peripheral nervous system autoimmune disease Guillain-Barré syndrome.

Cryptosporidium(choice B) causes a small bowel rather than colonic infection, as was demonstrated by sigmoidoscopy.

Giardia lamblia(choice C) causes nausea, vomiting, eructations, and upper gastrointestinal symptoms more commonly than diarrhea.

Herpes simplex (choice D) does not cause a bowel infection.

Yersinia enterocolitica(choice E) tends to infect the area of the cecum rather than the distal colon, causing right lower quadrant findings and diarrhea that can mimic the symptoms of Crohn disease

Front 3

A 24-year-old white woman presents complaining of 6 months of crampy abdominal pain. The pain has been localized to the right lower quadrant and is made worse by eating. She has also noted an increase in the number of her bowel movements to approximately four per day, and the stools have become semi-formed. She denies any fevers, chills, or night sweats during this period. She has lost 15 pounds from her baseline weight of 128 pounds over the past 6 months. She has also noted aching in her knees and ankles during this interval. On physical examination, she is slightly pale and has two oral aphthous ulcers on the inner lower lip. The abdomen is soft but tender in the right lower quadrant. No masses are palpable, and there is no hepatosplenomegaly. A rectal examination reveals brown stool, which is guaiac positive. Which of the following diagnostic tests would be most appropriate for this patient?

A. Abdominal CT scan
B. Barium enema
C. Sigmoidoscopy
D. Abdominal sonogram scan
E. Upper gastrointestinal and small bowel barium x-ray films

Back 3

The correct answer is E. This patient has the classic presentation of Crohn disease. This generally presents in young adults with subacute or chronic symptoms, typically of right lower quadrant pain, diarrhea, and weight loss. She also has extraintestinal manifestations of aphthous ulcers and arthralgias. The description of this patient's pain suggests that it is located in the terminal ileum. This area is best seen with an upper gastrointestinal and small bowel barium study.

An abdominal CT scan (choice A) is sometimes useful in patients with Crohn disease with a suspected abscess or fistula. However, this is not suggested by the history or physical in this case.

An abdominal sonogram (choice B) would not provide sufficient infromation for the diagnosis of Crohn disease. Barium studies are much better for visualization of the typical features of inflammatory bowel disease.

A barium enema (choice C) is not as effective a test as a small bowel series at visualizing the terminal ileum. The barium enema would demonstrate evidence of colonic Crohn disease but the history and physical here suggest ileal disease is more likely.

A sigmoidoscopy (choice D) would not be of value in assessing the terminal ileum.

Front 4

A 22-year-old man is diagnosed with Crohn disease limited to the terminal ileum. His symptoms of mild right lower quadrant pain and postprandial diarrhea resolve after the initiation of treatment with mesalamine. Two years later, he develops recurrent episodes of abdominal distention, nausea, and vomiting after large meals. On two occasions, these symptoms are accompanied by inability to pass flatus or bowel movements. Which of the following has this patient most likely developed?

A. Fibrosis and a stricture in the terminal ileum
B. A fistula from the ileum to the sigmoid
C. Gastric outlet obstruction
D. An obstructing cecal carcinoma
E. An obstructing ileal carcinoid

Back 4

The correct answer is A. This patient with Crohn disease has developed symptoms of a small bowel obstruction, which is a common and important complication of this condition. This occurs in Crohn disease as a result of chronic transmural inflammation, which both partially destroys the normal bowel wall and constricts it with thick bands of fibrosis. Other important intestinal complications can include fistula formation and chronic abscesses. In addition, a wide variety of extraintestinal complications can include autoimmune diseases (arthritis, aphthous ulcers, erythema nodosum, pyoderma gangrenosum, eye involvement, ankylosing spondylitis primary sclerosing cholangitis) and complications related to disrupted bowel physiology (renal complications, including kidney stones and urinary tract obstruction, malabsorption, and amyloidosis secondary to longstanding inflammation).

A fistula from the ileum to the sigmoid (choice B) can develop in patients with Crohn disease but will present with symptoms of diarrhea (because of the bypass of a large portion of the colon) and not obstruction.

Gastric outlet obstruction (choice C) may produce vomiting, usually of only partially digested foods, and does not usually result in significant abdominal distension. Furthermore, there is no impairment of passage of flatus or bowel movements.

Cecal carcinoma (choice D) can cause obstruction, but it would be extraordinarily rare in a 22-year-old man. Carcinoma is more likely to complicate ulcerative colitis than Crohn disease.

There is nothing in his history to suggest the development of carcinoid syndrome (choice E) in this young patient. These tumors, when they do occur, rarely present with a bowel obstruction, but may present with the carcinoid syndrome, i.e., facial flushing, diarrhea, wheezing, and tricuspid regurgitation.

Front 5

A 21-year old college senior presents with a 2-month history of frequent episodes of loose stool, preceded by lower abdominal cramping. Over the past 4 weeks, the stools have become increasingly bloody. On a number of occasions he has the sensation of rectal fullness but is unable to pass any fecal matter. A sigmoidoscopy is performed and reveals inflammation in a circumferential pattern from the anal verge to the mid-sigmoid colon, where a transition to normal mucosa is seen. Which of the following is the most appropriate treatment for this patient?

A. IV hydrocortisone
B. IV infliximab
C. Oral azathioprine
D. Oral prednisone
E. Topical mesalamine

Back 5

The correct answer is E. The patient described here has ulcerative colitis confined to the distal colon, also known as ulcerative proctosigmoiditis. Since the disease is limited to the distal colon, topical agents such as mesalamine (or alternatively hydrocortisone) would be effective in reducing inflammation. Mesalamine is an anti-inflammatory drug used principally to control ulcerative colitis. Its active ingredient is also known as 5-aminosalicylic acid, which is available in the forms of rectal suspension, suppositories, delayed release oral tablets, and controlled release oral capsules. The mode of action is unknown, but is thought to involve topical (since mesalamine is poorly absorbed), rather than systemic, modulation of arachidonic acid metabolites, including prostaglandins, leukotrienes, and hydroxyeicosatetraenoic acids. It is usually well tolerated, but it can cause significant allergic reactions related to sulfite sensitivity.

IV hydrocortisone (choice A) is reserved for patients who do not respond to high doses of oral prednisone.

IV infliximab (choice B) is used for patients with severe refractory Crohn disease.

Oral azathioprine (choice C) is used in Crohn disease and ulcerative colitis in patients already refractory or dependent on steroids to control symptoms or maintain remission.

Oral prednisone (choice D) is not warranted in patients who have not been treated previously with safer medications, such as topical mesalamine or hydrocortisone or oral mesalamine or sulfasalazine.