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Select the ONE answer that is BEST in each case.
A 56-year-old woman presents with weight loss and watery diarrhea. She also notices periumbilical pain and bloating after eating. A small bowel x-ray reveals an area of narrowing and the lesion is surgically resected. The pathology report shows this to be the most common endocrine tumor of the GI tract.
Carcinoid tumors account for up to 75% of all GI endocrine tumors. They are frequently multiple. Primary carcinoid tumors of the appendix are common but rarely metastasize. Those in the large colon may metastasize but do not function. Carcinoids are the most common GI endocrine tumors. They arise from neuroendocrine cells most commonly in the GI tract, pancreas, or bronchi. GI carcinoids cause abdominal pain, bleeding, or even obstruction (usually via intussusception). Carcinoid syndrome is characterized by flushing, diarrhea, and valvular heart disease.
A 72-year-old man is investigated for iron deficiency anemia. There is no clinical history of upper or lower GI bleeding, but his stools are fecal occult blood positive. His colonoscopy is negative for any obvious sources of bleeding, but upper endoscopy reveals ulceration in the distal duodenum that is biopsied. The pathology report shows this to be the most common primary malignancy of the small bowel.
Adenocarcinoma of the small bowel accounts for about 50% of malignant tumors of the small bowel. They are most commonly found in the distal duodenum and proximal jejunum. Hemorrhage, or obstruction, is the most common presenting symptom. X-ray findings can mimic chronic duodenal ulcer disease or Crohn’s disease.
A 23-year-old man of Middle Eastern decent is investigated for symptoms of chronic diarrhea, vomiting, and abdominal cramps. He has lost 20 lb and appears unwell. A small bowel x-ray shows diffuse nonspecific mucosal abnormality. Upper endoscopy is performed to visualize the small bowel and obtain biopsies. The pathology report identifies the mucosal abnormality as “immunoproliferative small intestinal disease” (IPSID). This form of small bowel tumor can be treated with antibiotics in its early stages.
There is one unique form of lymphoma called IPSID or Mediterranean lymphoma. It diffusely involves the small intestine and usually presents with diarrhea and steatorrhea. Oral antibiotics, early in the disease, provide some benefit, suggesting a possible infectious component to the disorder. Antibiotics and chemotherapy are frequently combined.
A 21-year-old woman develops acute periumbilical pain that localizes to the right lower quadrant. She appears unwell, and on examination, there is tenderness and guarding in the right lower quadrant. A pregnancy test is negative and a pelvic examination rules out pelvic inflammatory disease. A clinical diagnosis of acute appendicitis is made and she has an uncomplicated laparoscopic appendectomy. The pathology report notes acute inflammation and a tumor for which the appendix is a very common site of involvement.
Appendiceal tumors make up nearly half of all carcinoid tumors and are a frequent finding in routine appendectomy specimens. They are usually small, solitary, and benign. Even if they invade locally, they rarely metastasize.
A 57-year-old woman with a 20-year history of celiac disease now presents with weight loss, cramps, and abdominal discomfort. She is adherent to her gluten-free diet, and is not taking any new medications. On examination, her abdomen is soft and there is fullness in the right lower quadrant. A small bowel x-ray reveals an area of narrowing in the distal ileum, and there is thickening and nodularity of the mucosal folds. She undergoes surgical resection of the lesion, and the pathology report confirms a tumor that is more common in patients with celiac disease, Crohn’s disease, or depressed immune function such as human immunodeficiency virus (HIV).
Primary small bowel lymphoma is more common in the settings of celiac disease, regional enteritis, congenital immune disorders, prior organ transplantation, autoimmune disorders, and AIDS.
A 43-year-old woman has had a 10-year history of severe and recurrent peptic ulcer disease (PUD) that is refractory to medical therapy. She has had ulcers at multiple sites of the small bowel including the distal duodenum and jejunum. She also has chronic diarrhea, but not enough fat to make the diagnosis of steatorrhea. Evaluation for Helicobacter pyloriinfection is negative.
Zollinger-Ellison syndrome is caused by a nonbeta islet cell tumor of the pancreas. It may be associated with the syndrome of multiple endocrine neoplasia, type I (MEN I). The syndrome should be suspected in patients with multiple ulcers, ulcers resistant to therapy, ulcers in unusual locations, strong family history of ulcers, unexplained diarrhea, or evidence of MEN I.
A 79-year-old woman with severe constipation is found to have multiple diverticuli on colonoscopy. Which of the following is the most appropriate next step in management?
Diverticula are present in over 50% of octogenarians. Most patients remain asymptomatic. They are most common in the sigmoid colon and decrease in frequency in the proximal colon. The relative scarcity of diverticula in underdeveloped nations has led to the hypothesis that low fiber diets result in decreased fecal bulk, narrowing of the colon, and an increased intraluminal pressure to move the small fecal mass. This results in thickening of the muscular coat, and eventually herniations or diverticula of the mucosa at the points where nutrient arteries penetrate the muscularis.
A 77-year-old woman is brought to the emergency room because of nonspecific abdominal discomfort. She has no anorexia, fever, chills, or weight loss. Her abdomen is soft and nontender on physical examination. Abdominal x-rays show lots of stool in the colon, but no free air or air-fluid levels. The amylase is 150 U/L (25–125 U/L), and the rest of her biochemistry and complete blood count are normal. Which of the following conditions can cause a falsepositive elevation in the serum amylase?
Amylase accumulates in the setting of renal failure and thus becomes a less-valuable diagnostic test. Numerous other conditions involving the pancreas, the gut, and the salivary glands can raise amylase levels. Sulfonamides cause pancreatitis; therefore, an elevated amylase is not confusing, but rather a useful test for pancreatitis in patients taking the drug. Morphine can elevate amylase levels in the absence of pancreatitis.
A 71-year-old man develops progressive weight loss and dysphagia over a 3-month period. Upper endoscopy and biopsy of the lesion confirm esophageal cancer. Which of the following statements regarding this cancer is most likely correct?
This presentation is typical of esophageal cancer. Lesions in the upper two-thirds of the esophagus are squamous, but in the distal esophagus, most are adenocarcinomas. The adenocarcinomas develop more commonly from columnar epithelium in the distal esophagus (Barrett’s esophagus). Adenocarcinomas of the esophagus have the biologic behavior of gastric cancers. The incidence of squamous cell cancer of the esophagus is decreasing while adenocarcinoma is increasing. Currently, over 50% of esophageal cancer is adenocarcinoma. The 5-year survival for esophageal cancer is <5%. Combination therapy seems to be more effective than surgery alone.
A 23-year-old woman presents with weight loss and chronic diarrhea. She appears unwell and cachectic. Routine laboratory tests reveal a low hemoglobin level and an increased international normalized ratio (INR) even though she is not taking any anticoagulants. The liver enzymes are normal, but the albumin and calcium levels are low, suggesting generalized malnutrition. Which of the following is the most appropriate initial diagnostic test for malabsorption?
Fat malabsorption demonstrated on stool collection for 72 hours is the gold standard, but does not indicate the exact cause. The Schilling test is useful in testing for vitamin B 12 absorption. X-rays can be helpful in diagnosing underlying disorders, but are nonspecific. Small intestinal biopsy is useful in determining the cause of malabsorption.
A 33-year-old man has never been vaccinated for hepatitis B. Serologic tests reveal negative hepatitis B surface antigen (HBsAg) and positive antibody to surface antigen. Which of the following conditions does this serologic pattern best fit with?
The antibody can be demonstrated in 80–90% of patients, usually late in convalescence, and indicates relative or absolute immunity. In contrast, HBsAg occurs very early and disappears in <6 months. Persistence of HBsAg indicates chronic infection. The pattern in this patient is also seen postvaccination, and perhaps as a consequence of remote infection.
A 29-year-old woman is found, on routine annual blood testing, to have an increase in unconjugated bilirubin. There is no evidence of hemolysis and liver tests are otherwise normal. Which of the following is the most likely diagnosis?
Gilbert’s syndrome may be associated with impaired hepatic uptake of bilirubin. It is caused by hereditary decrease in the activity of glucoronosyltransferase in the uridine diphosphate glycosyltransferase 1 (UGT1) family. More severe enzyme deficits are the cause of the two variants of Crigler-Najjar syndrome.
An 18-year-old woman was diagnosed 7 years earlier with precocious pseudopuberty secondary to ovarian tumor. Physical examination reveals oral and lingual dark pigmentation. Which of the following is the most likely diagnosis?
Intestinal polyposis is a possible indication of Peutz-Jeghers syndrome associated with dark brown spots on the lips and palate. There is characteristic distribution of pigment around lips, nose, eyes, and hands. Tumors of the ovary, breast, pancreas, and endometrium are associated with this syndrome.
A 63-year-old man has stools positive for occult blood. Which of the following is the most likely location of bowel cancer?
Despite some decline, distal tumors are still the most common. The fact that up to 60% of tumors are located in the rectosigmoid is the rationale for screening via flexible, fiberoptic sigmoidoscopes. Occult blood testing and colonoscopy are other possible screening techniques.
A 74-year-old man underwent some type of peptic ulcer surgery years ago. He has symptoms that include abdominal pain and bloating about 30–40 minutes after eating, accompanied by nausea. If he vomits, the symptoms are relieved. Which of the following is the most likely cause for his symptoms?
This pattern of symptoms is characteristic of afferent loop syndrome. It is caused by distention and incomplete drainage of the afferent loop and requires surgical correction. Bacterial overgrowth of the afferent loop is more common. Its clinical presentation includes postprandial abdominal pain, bloating, and diarrhea. Fat and vitamin B 12 malabsorption can occur.
A 29-year-old man with acquired immune deficiency syndrome (AIDS) comes to the emergency department because of progressively increasing abdominal discomfort. Examination shows voluntary guarding in the upper abdomen. His biochemistry is normal except for an elevated amylase at 370 U/L (25–125 U/L). Which of the following infections can trigger this disorder in AIDS patients?
Pancreatitis in AIDS patients can be caused by cytomegalovirus and cryptosporidium as well as M. aviumcomplex. Drugs are another cause of AIDS-related pancreatitis.
A 55-year-old man from China is known to have chronic liver disease, secondary to hepatitis B infection. He has recently felt unwell, and his hemoglobin level has increased from 130 g/L, 1 year ago, to 195 g/L. Which of the following is the most appropriate initial diagnostic test?
Hepatoma is the most likely diagnosis in this man. In China, it is estimated that the lifetime risk of hepatoma in people with chronic hepatitis B is close to 40%. AFP elevations, over 500–1000 mg/L in the absence of a colonic tumor (or pregnancy), suggest hepatoma. Paraneoplastic syndromes are not common but include erythrocytosis, hypercalcemia, and acquired porphyria.
A 63-year-old man with a long history of alcohol abuse presents with ascites. He is experiencing mild abdominal discomfort and nausea. Examination reveals tense ascites and generalized tenderness but no rigidity. A diagnostic paracentesis of the fluid is performed. Which of the following ascitic fluid results is most likely to suggest an uncomplicated ascites due to portal hypertension from cirrhosis?
Ascitic fluid in uncomplicated cirrhosis of the liver shows a specific gravity <1.016. Protein is <25 g/L, and the gross appearance is straw-colored. In spontaneous bacterial peritonitis, the fluid may be cloudy and the number of white cells (neutrophils) increased. In uncomplicated ascites, the difference between plasma albumin and ascitic fluid albumin is >1.1 g/dL.
A 64-year-old woman develops sudden-onset abdominal discomfort after eating a large meal. The pain is constant, localizes to the epigastric area with radiation to her right scapula. She also has nausea and vomiting. It eventual subsides 1 hour later. An ultrasound of the abdomen reveals a dilated common bile duct secondary to stones. Which of the following statements regarding common bile duct stones is most likely true?
Common duct stones can be painless, or may give rise to severe pain, chills, and fever. The jaundice is generally conjugated hyperbilirubinemia. Partial obstruction of the common duct produces variable amounts of jaundice and is influenced by the presence of concurrent hepatocellular disease or cholangitis. Although most such stones originate in the gallbladder, hemolytic disorders and parasitic infections can result in primary bile duct stones.
A 53-year-old man presents with diarrhea. He also complains of facial flushing lasting minutes at a time. Physical examination reveals facial telangiectasias and a heart murmur not present 2 years before. This murmur is accentuated by deep breathing. Which of the following is the most appropriate initial diagnostic test?
The syndrome is characteristic of carcinoid of midgut origin. The cardiac lesions are more common on the right side (hence murmur accentuation on deep inspiration). Foregut carcinoids (bronchus, stomach, duodenum) frequently are associated with wheezing. The most important mediator of the carcinoid syndrome is serotonin. Serotonin is rapidly metabolized to 5-HIAA, which is rapidly cleared by the kidneys. The measurement of 5-HIAA in the urine is thus the most useful diagnostic test. Its specificity is enhanced by an appropriate diet before testing.
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