Diarrhea Case 1

A 52-year-old woman consults a physician because she has been having increasingly frequent episodes of abdominal cramps and diarrhea.

These episodes are accompanied by an uncomfortable flushing of her skin. She thinks they are sometimes precipitated by eating, alcohoI, or emotional distress, but she has also recently been having episodes that had no obvious trigger.

Q 1

Her physician suspects that she may have a hormone-secreting tumor. Ectopic secretion of which of the following substances would be most

Iikely to cause diarrhea?

/ A. Gastrin

/ B. GIucagon

/ C. Histamine

/ D. Insulin

/ E. Serotonin

Q2

Which of the following laboratory tests would be most appropriate to test for excess secretion of the hormone causing the diarrhea?

/ A. Dexamethasone test

/ B. Hemoglobin A1C

/ C. Urinary 5-hydroxyindoleacetic acid

/ D. Urinary aminolevulinic acid

/ E. Urinary porphobilinogen

Q 3

CT scan demonstrates several probable metastatic tumors in the patient's liver. These are most likely which of the following histologic types?

/ A. Burkitt lymphoma

/ B. Carcinoid tumor

/ C. Hepatocellular carcinoma

/ D. Kaposi sarcoma

/ E. Squamous cell carcinoma

Q 4

The metastases most likely originated from which of the following?

/ A. Central nervous system

/ B. Gastrointestinal tract

/ C. Reproductive tract

/ D. Respiratory tract

Q 5

These tumors are thought to be derived from which of the following cell lines?

/ A. Endothelial cells

/ B. Enterochromaffin cells

/ C. Fibroblasts

/ D. Lymphocytes

/ E. Smooth muscle cells

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Diarrhea Case 1 Answers

A1

The correct answer is E. Excess serotonin can act on smooth muscle to produce diarrhea, colic, and malabsorption.

Excess gastrin secretion (choice A) can cause peptic ulceration secondary to stimulation of gastric glands.

Excess glucagon secretion (choice B) can cause rash and impaired glucose tolerance.

Excess histamine secretion (choice C), as well as excess bradykinin secretion, can coexist with excess serotonin secretion, and can contribute to the flushing seen in this patient.

Excess insulin secretion (choice D) can cause hypoglycemia.

A2

The correct answer is C. 5-hydroxyindoleacetic acid is the major urinary metabolite of serotonin.

The dexamethasone test (choice A) is used to screen for Cushing syndrome.

Hemoglobin A1c (choice B) is a marker for long-term glycemic control.

Urinary porphobilinogen (choice E) and urinary aminolevulinic acid (choice D) are used in the diagnosis of the porphyrias.

A3

The correct answer is B. The patient's clinical presentation is typical for carcinoid syndrome, which is a clinical manifestation of hormone-secreting carcinoid tumors. It is usually seen in the presence of metastatic disease involving the liver. None of the other tumors listed would be expected to secrete hormones.

A4

The correct answer is B. Approximately 90% of carcinoid tumors occur in the gastrointestinal tract, with the most common site in the gastrointestinal tract being the small intestine (39%, data from www.carcinoid.org web site). Involvement of the appendix (26%) and rectum (15%) is also fairly common. Other sites include colon (5-7%), stomach (2-4%), pancreas (2-3%), liver (less than 1%), bronchial system (10%, choice D), and rarely gonads (choice C), gallbladder and bile ducts, urinary bladder and kidneys (choice E), prostate, breast, and thymus. The central nervous system (choice A) does not appear to be a significant site of origin.

A5

The correct answer is B. Carcinoid tumors are thought to be derived from the glandular endocrine hormone-producing cells, known as enterochromaffin cells, which are widely distributed through the body. They occupy a borderline category between benign and malignant, because only a fairly small percentage of them eventually metastasize, and pathologists are unable, histologically, to tell which ones will or will not. Most of the malignant ones are derived from the small intestine (1/5 metastasize and 1/3 of those cause carcinoid syndrome), and they tend to produce the clinical symptoms of carcinoid syndrome illustrated in the case history only when they have metastasized to the liver. The tumors probably secrete hormones prior to metastasis; the absence of carcinoid syndrome in these patients is attributed to the fact that the venous drainage of the gut passes through the liver via the portal system, clearing the blood of excess vasoactive substances. Also, some of the tumors do not secrete clinically significant amounts of hormones. Serotonin, histamine, and bradykinin are the most common hormones secreted that produce symptoms. Carcinoid tumors are found incidentally in approximately 0.5% of appendectomy specimens; appendiceal carcinoids only rarely metastasize. The tumors may also be a component of the multiple endocrine neoplasia (MEN) syndromes. Tumors that are identified incidentally before metastasis can be cured surgically. No effective chemotherapy or radiotherapy is available for metastatic disease, but the tumors grow so slowly that 10-15 year survival times are not unusual. The somatostatin analog octreotide can help control symptoms.

Endothelial cells (choice A) give rise to vascular tumors such as Kaposi sarcoma and angiosarcoma.

Fibroblasts (choice C) can give rise to a variety of fibromas and fibrosarcomas.

Lymphocytes (choice D) can give rise to leukemias and lymphomas.

Smooth muscle cells (choice E) can give rise to leiomyomas and leiomyosarcomas.

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Gastrointestinal Bleeding case 5

A 47-year-old, darkly pigmented man with a known history of alcohol abuse begins vomiting large quantities of blood and is brought by ambulance to the emergency department.

Q 1

In the emergency department, the man is found to have a temperature of 36.7 C (98.1 F), blood pressure of 65/40 mm Hg and dropping rapidly, a weak pulse of 130/min, and respirations of 29/min. These vital signs suggest that which of the following is developing?

/ A. Congestive heart failure

/ B. Meningitis

/ C. Pneumonia

/ D. Septicemia

/ E. Shock

Q 2

A blood sample is drawn and an IV Iine is started. While the patient is being cross-matched, the physical examination is continued. The patient's sclerae are noted to be icteric and his nail beds and palms have a yellowish hue. A caput medusa

is noted. Which of the following is the most accurate description of a caput medusa?

/ A. Ecchymoses over the mastoid process

/ B. Paradoxical increase in venous distension and pressure during inspiration

/ C. Reflex movement of the eyes in the opposite direction to that in which the head is moved

/ D. Small bony masses found on the terminal phalanges

/ E. Varicose veins radiating from the area of the umbilicus

Q 3

Caput medusa specifically suggests which of the following diagnoses?

/ A. BIadder infection

/ B. Duodenal ulcer

/ C. Gastric ulcer

/ D. Pancreatitis

/ E. Portal hypertension

Q 4

Which of the following is the most common cause of this patient's disorder in the United States?

/ A. Hepatic cirrhosis

/ B. Hepatic vein thrombosis

/ C. Hepatocellular carcinoma

/ D. Metastatic disease to the liver

/ E. Portal vein thrombosis

Q 5

Endoscopic studies demonstrate that this patient has bleeding esophageal varices, and the bleeding is successfully stopped with

sclerotherapy. What percentage of patients with bleeding esophageal varices have another episode of variceal bleeding at a subsequent

time?

/ A. 5%

/ B. 25%

/ C. 40%

/ D. 70%

/ E. 95%

Q 6

Following blood transfusions and sclerotherapy, the patient initially feels reasonably well and is able to converse with medical personneI. Over

the next 12 hours, while he does not begin to rebleed, his mental status deteriorates. Arterial blood levels of which of the following would be

most helpful in confirming the likely diagnosis?

/ A. Ammonia

/ B. Angiotensin l

/ C. Calcitonin

/ D. Carbon monoxide

/ E. Ceruloplasmin

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Gastrointestinal Bleeding case 5 answers

A1

The correct answer is E. The patient's low and dropping blood pressure, tachycardia, high respiratory rate, and slightly below normal body temperature are all consistent with impending shock. At this point, the other conditions listed in the choices have not yet been ruled out, but clinically, the patient should begin to be immediately treated for the shock, even if the therapeutic workup for underlying conditions must be temporarily deferred

A2

The correct answer is E. Medusa was a goddess with snakes instead of hair on her head. The caput medusa (Medusa's head) is an old term still in fairly common use for numerous varicose veins radiating over the abdomen from the area of the umbilicus.

Choice A describes Battle's sign, which is suggestive of basal skull fracture.

Choice B describes Kussmaul's sign, which is seen in constrictive pericarditis.

Choice C describes the doll's eye sign, which is looked for in the evaluation of comatose patients and suggests functional integrity of the brainstem tegmental pathways and cranial nerves involved in eye movement.

Choice D describes Heberden's nodules, which are seen in osteoarthritis.

A3

The correct answer is E. The caput medusa develops when severe portal hypertension induces dilation of the anastomotic channels between the portal venous system and the systemic venous system, some of which involve the superficial veins near the umbilicus. The other answers are distracters.

A4

The correct answer is A. The overwhelmingly most common cause of portal hypertension in the United States is hepatic cirrhosis, which is usually due to either alcoholism or hepatitis viral infection. In this patient's case, the diagnosis of cirrhosis is further clinically substantiated by his jaundice, as evidenced by his sclera, nail beds, and palms. (Look in these areas on individuals in whom dark skin pigmentation may mask the jaundice generally.) The other entities listed are occasional causes of portal hypertension.

A5

The correct answer is D. Patients who have had one episode of bleeding from esophageal varices have an approximately 70% chance of developing a second incident of bleeding, and one third of these episodes of rebleeding is fatal.

A6

The correct answer is A. Hepatic encephalopathy is seen in end-stage cirrhosis patients, and can either present or worsen in the presence of gastrointestinal bleeding. The blood in the upper gastrointestinal tract behaves essentially as a high protein load, and increases the absorption of ammonia and nitrogen, which cannot be appropriately metabolized by the liver. GI bleeding may also predispose for inadequate renal function secondary to hypotension.

Angiotensin I (choice B) is part of the renin-angiotensin-aldosterone system for blood pressure and sodium ion control.

Calcitonin (choice C) is a hormone secreted by the thyroid, which may be increased in medullary carcinoma of the thyroid.

Carbon monoxide (choice D) increases in the blood in smokers.

Ceruloplasmin (choice E) is a copper-carrying protein monitored in patients with Wilson disease.