August 2012 - Gastroenterology - Quiz, Flashcards & Trivia

1. A 57-year-old woman is evaluated in the emergency department for acute left lower quadrant pain, an episode of nonbloody diarrhea, and mild nausea without vomiting that began 1 day ago; her temperature at the time was 38.1 °C (100.6 °F). She has been able to eat and maintain her hydration with oral fluids. She had been previously healthy and has no significant medical history. On physical examination, the temperature is 38.1 °C (100.6 °F), the blood pressure is 115/76 mm Hg, the pulse rate is 98/min, and the respiration rate is 14/min. There is tenderness of the left lower quadrant with no rebound, guarding, or palpable masses. Leukocyte count is 14,900/µL (14.9 m 109/L); all other laboratory results are normal. Contrast-enhanced CT scan of the abdomen and pelvis shows diverticula of the sigmoid colon with pericolic fatty infiltration and thickening of the bowel wall consistent with diverticulitis; there is no abscess, obstruction, or fistula. Which of the following is the most appropriate next step in the management of this patient?

Flexible sigmoidoscopy

Oral ciprofloxacin and metronidazole therapy

Oral cephalexin therapy

Surgical resection

The most appropriate next step in the management of this patient is oral ciprofloxacin and metronidazole therapy. The patient's clinical presentation, physical examination findings, and CT scan results are consistent with diverticulitis. Diverticulitis is the inflammation or infection of the diverticula, which are small pouches that can form in the lining of the colon. The recommended treatment for uncomplicated diverticulitis without abscess or fistula is oral antibiotics, such as ciprofloxacin and metronidazole, to cover for both aerobic and anaerobic bacteria. Surgical resection is typically reserved for complicated cases or recurrent diverticulitis. Flexible sigmoidoscopy is not indicated in the acute setting. Oral cephalexin therapy is not appropriate as it does not cover the anaerobic bacteria commonly involved in diverticulitis.

Explanation

The most appropriate next step in the management of this patient is oral ciprofloxacin and metronidazole therapy. The patient's clinical presentation, physical examination findings, and CT scan results are consistent with diverticulitis. Diverticulitis is the inflammation or infection of the diverticula, which are small pouches that can form in the lining of the colon. The recommended treatment for uncomplicated diverticulitis without abscess or fistula is oral antibiotics, such as ciprofloxacin and metronidazole, to cover for both aerobic and anaerobic bacteria. Surgical resection is typically reserved for complicated cases or recurrent diverticulitis. Flexible sigmoidoscopy is not indicated in the acute setting. Oral cephalexin therapy is not appropriate as it does not cover the anaerobic bacteria commonly involved in diverticulitis.

2. A 55-year-old woman is evaluated for a 4-month history of progressive fatigue and pruritus. She is otherwise healthy and takes no medications. On physical examination, vital signs are normal; BMI is 25. Examination reveals mild hepatomegaly and excoriations of the skin. There is no jaundice, rash, or skin eruption. Laboratory studies: Bilirubin (total) 1.5 mg/dL (25.6 µmol/L) Aspartate aminotransferase 60 U/L Alanine aminotransferase 75 U/L Alkaline phosphatase 470 U/L Albumin 4.0 g/dL (40 g/L) Hepatitis C virus antibody Negative Hepatitis B surface antigen Negative Ultrasonography of the abdomen is normal with no bile duct dilatation. Which of the following is the most appropriate next step in the diagnosis of this patient?

A1 - Antitrypsin phenotype

Liver biopsy

Measurement of serum antimitochondrial antibody

Serum protein electrophoresis

The most appropriate next step in the diagnosis of this patient is to measure serum antimitochondrial antibody. This is because the patient's presentation of progressive fatigue, pruritus, and hepatomegaly is suggestive of primary biliary cholangitis (PBC), which is an autoimmune liver disease. The characteristic laboratory findings of elevated alkaline phosphatase and positive antimitochondrial antibody support the diagnosis of PBC. Liver biopsy may be considered if the diagnosis remains uncertain after serologic testing. Antitrypsin phenotype and serum protein electrophoresis are not indicated in this patient's presentation.

Explanation

The most appropriate next step in the diagnosis of this patient is to measure serum antimitochondrial antibody. This is because the patient's presentation of progressive fatigue, pruritus, and hepatomegaly is suggestive of primary biliary cholangitis (PBC), which is an autoimmune liver disease. The characteristic laboratory findings of elevated alkaline phosphatase and positive antimitochondrial antibody support the diagnosis of PBC. Liver biopsy may be considered if the diagnosis remains uncertain after serologic testing. Antitrypsin phenotype and serum protein electrophoresis are not indicated in this patient's presentation.

3. A 63-year-old woman has a 3-month history of gradually increasing abdominal distention and fatigue. She has no other symptoms, and medical history is noncontributory. On physical examination, the patient has jaundice and evidence of mild muscle wasting. Xanthelasma and spider angiomata are present. Abdominal examination discloses hepatosplenomegaly and moderate ascites. Laboratory Studies Aspartate aminotransferase 53 U/L Alanine aminotransferase 47 U/L Alkaline phosphatase 123 U/L Total bilirubin 3.2 mg/dL Albumin 2.9 g/dL Abdominal ultrasonography shows hepatomegaly, a coarse echotexture of the liver, patent portal and hepatic veins, mild splenomegaly, moderate ascites, and no bile duct dilatation. Paracentesis is performed. The ascitic fluid leukocyte count is 80/μL, protein is 1.4 g/dL, and albumin is 0.7 g/dL. Which of the following is the most likely cause of the ascites?

Budd-Chiari syndrome

Cirrhosis

Heart failure

Peritoneal carcinomatosis

The most likely cause of the ascites in this patient is cirrhosis. The patient's history of gradually increasing abdominal distention and fatigue, along with physical examination findings such as jaundice, hepatosplenomegaly, and moderate ascites, are consistent with cirrhosis. The laboratory studies also support this diagnosis, with abnormalities in liver enzymes (AST, ALT, alkaline phosphatase) and bilirubin levels, as well as low albumin levels. The abdominal ultrasonography findings of hepatomegaly, coarse echotexture of the liver, and splenomegaly further suggest cirrhosis. The ascitic fluid analysis is also consistent with cirrhosis, showing a low leukocyte count, low protein level, and low albumin level.

Explanation

The most likely cause of the ascites in this patient is cirrhosis. The patient's history of gradually increasing abdominal distention and fatigue, along with physical examination findings such as jaundice, hepatosplenomegaly, and moderate ascites, are consistent with cirrhosis. The laboratory studies also support this diagnosis, with abnormalities in liver enzymes (AST, ALT, alkaline phosphatase) and bilirubin levels, as well as low albumin levels. The abdominal ultrasonography findings of hepatomegaly, coarse echotexture of the liver, and splenomegaly further suggest cirrhosis. The ascitic fluid analysis is also consistent with cirrhosis, showing a low leukocyte count, low protein level, and low albumin level.

4. A 63-year-old man is evaluated for a 2-day history of left lower quadrant abdominal pain. The pain is constant and is not relieved by a bowel movement or by positional changes. The patient is slightly nauseated and has no appetite but is not vomiting. He has never had a similar episode. The patient's medical history includes hypertension, and his only medication is hydrochlorothiazide. On physical examination, the temperature is 38.0 °C (101.1 °F), the blood pressure is 125/85 mm Hg, the pulse rate is 95/min, and the respiration rate is 14/min. There is fullness and tenderness of the left lower quadrant with no rebound or guarding; bowel sounds are decreased. Rectal examination is normal; examination of stool for occult blood is negative. Leukocyte count is 14,000/µL (14 m 109/L); all other laboratory results are normal. A plain abdominal radiograph is unremarkable, and a chest radiograph shows no free air beneath the diaphragms. Which of the following is the most appropriate next step in the evaluation of this patient?

Barium enema

Colonoscopy

Contrast-enhanced CT scan of the abdomen and pelvis

Small-bowel radiographic series

The patient's presentation with left lower quadrant abdominal pain, fever, and leukocytosis raises concern for diverticulitis, which is inflammation or infection of a diverticulum in the colon. The most appropriate next step in the evaluation is a contrast-enhanced CT scan of the abdomen and pelvis. This imaging modality is highly sensitive and specific for diagnosing diverticulitis and can help determine the severity of the condition, guide treatment decisions, and rule out other causes of abdominal pain. A barium enema, colonoscopy, and small-bowel radiographic series are not the initial recommended tests for evaluating diverticulitis.

Explanation

The patient's presentation with left lower quadrant abdominal pain, fever, and leukocytosis raises concern for diverticulitis, which is inflammation or infection of a diverticulum in the colon. The most appropriate next step in the evaluation is a contrast-enhanced CT scan of the abdomen and pelvis. This imaging modality is highly sensitive and specific for diagnosing diverticulitis and can help determine the severity of the condition, guide treatment decisions, and rule out other causes of abdominal pain. A barium enema, colonoscopy, and small-bowel radiographic series are not the initial recommended tests for evaluating diverticulitis.

5. A 58-year-old man is evaluated for a 3-month history of epigastric pain. The pain varies in intensity and is not aggravated by eating; it is not associated with nausea, vomiting, bloating, or weight loss. He started pantoprazole therapy 1 month ago without relief. The patient has a history of resolved peptic ulcer 3 years ago and osteoarthritis of the hands and knees, and his medications are ibuprofen as needed for arthritic pain and pantoprazole. On physical examination, vital signs are normal. There is mild epigastric tenderness, normal bowel sounds, and no hepatomegaly or lymphadenopathy. Complete blood count and serum chemistry tests, including liver enzymes, are normal. Esophagogastroduodenoscopy shows mild erythema and a few superficial erosions throughout the distal stomach and a 1-cm pedunculated polyp in the antrum of the stomach that is biopsied but not removed. Biopsy specimens of the erythematous gastric mucosa show chronic active gastritis and the presence of Helicobacter pylori; specimens of the polyp show a tubular adenoma with low-grade dysplasia. Eradication therapy for H. pylori is begun. Which of the following is the most appropriate additional management of this patient?

Endoscopic ultrasonography

Esophagogastroduodenoscopy with polypectomy now

Esophagogastroduodenoscopy in 3 years

Surgical resection

No further intervention

The patient has a 1-cm pedunculated polyp in the antrum of the stomach that shows low-grade dysplasia on biopsy. Low-grade dysplasia in a polyp indicates a precancerous lesion. Therefore, the most appropriate management would be to perform an esophagogastroduodenoscopy with polypectomy now to remove the polyp and prevent the progression to gastric cancer. Waiting for 3 years or opting for surgical resection may not be necessary at this stage, as the polyp can be removed endoscopically. Endoscopic ultrasonography may be considered if there are concerns about the depth of invasion of the polyp. No further intervention is not appropriate given the presence of a precancerous lesion.

Explanation

The patient has a 1-cm pedunculated polyp in the antrum of the stomach that shows low-grade dysplasia on biopsy. Low-grade dysplasia in a polyp indicates a precancerous lesion. Therefore, the most appropriate management would be to perform an esophagogastroduodenoscopy with polypectomy now to remove the polyp and prevent the progression to gastric cancer. Waiting for 3 years or opting for surgical resection may not be necessary at this stage, as the polyp can be removed endoscopically. Endoscopic ultrasonography may be considered if there are concerns about the depth of invasion of the polyp. No further intervention is not appropriate given the presence of a precancerous lesion.

6. A 66-year-old man presents with vague epigastric "gnawing" discomfort that occasionally awakens him from sleep. There has been no melena, hematochezia, fever, chills or weight loss. Past medical history includes asthma, a TI, and peptic ulcer disease many years prior. Medications are aspirin and beclomethasone inhaler. Physical examination reveals a soft abdomen, mildly tender in the epigastrium. A recent abdominal ultrasound is normal. What is the best initial test in the evaluation of this patient?

Upper gastrointestinal series

Upper endoscopy

MRI of the abdomen

CT scan with IV contrast

Serology for H. Pylori

The best initial test in the evaluation of this patient is upper endoscopy. This is because the patient's symptoms of vague epigastric discomfort, especially when it occasionally awakens him from sleep, along with his history of peptic ulcer disease, warrant further investigation of the upper gastrointestinal tract. Upper endoscopy allows direct visualization of the esophagus, stomach, and duodenum, which can help identify any abnormalities such as ulcers, inflammation, or tumors. It is a more specific and accurate test compared to other options such as an upper gastrointestinal series, MRI, CT scan, or serology for H. Pylori.

Explanation

The best initial test in the evaluation of this patient is upper endoscopy. This is because the patient's symptoms of vague epigastric discomfort, especially when it occasionally awakens him from sleep, along with his history of peptic ulcer disease, warrant further investigation of the upper gastrointestinal tract. Upper endoscopy allows direct visualization of the esophagus, stomach, and duodenum, which can help identify any abnormalities such as ulcers, inflammation, or tumors. It is a more specific and accurate test compared to other options such as an upper gastrointestinal series, MRI, CT scan, or serology for H. Pylori.

7. A 44-year-old man is evaluated in the hospital for 3-day history of five or six watery stools a day 3 months after surgical resection of the small bowel. The patient was recently diagnosed with a desmoid tumor involving the right transverse colon and ileum, and the tumor was resected, requiring removal of the proximal colon and 80 cm of distal ileum. The remaining small bowel was anastomosed to the mid-transverse colon. Vital signs and physical examination are normal. Which of the following is the most appropriate therapy for this patient?

Antibiotics

Cholestyramine

Prednisone

Tincture of opium

Cholestyramine is the most appropriate therapy for this patient because the symptoms of watery stools suggest that the patient may be experiencing bile acid malabsorption. Bile acids are normally reabsorbed in the distal ileum, but since the patient had 80 cm of distal ileum removed, it is likely that there is a deficiency in bile acid reabsorption. Cholestyramine is a bile acid sequestrant that can bind to bile acids in the intestine and prevent their reabsorption, thus reducing the frequency of watery stools. Antibiotics, prednisone, and tincture of opium are not appropriate therapies for this condition.

Explanation

Cholestyramine is the most appropriate therapy for this patient because the symptoms of watery stools suggest that the patient may be experiencing bile acid malabsorption. Bile acids are normally reabsorbed in the distal ileum, but since the patient had 80 cm of distal ileum removed, it is likely that there is a deficiency in bile acid reabsorption. Cholestyramine is a bile acid sequestrant that can bind to bile acids in the intestine and prevent their reabsorption, thus reducing the frequency of watery stools. Antibiotics, prednisone, and tincture of opium are not appropriate therapies for this condition.

8. An 81-year-old woman is evaluated for a 3-month history of abdominal and back pain. She also has anorexia and has lost 11.4 kg (25 lb). For the past 2 weeks she has had progressive pruritus and a yellow tint to her skin. On physical examination, the patient appears ill; the temperature is 37.2 °C (99 °F), the blood pressure is 104/62 mm Hg, the pulse rate is 98/min, and the respiration rate is 16/min. There is scleral icterus, jaundiced skin, and generalized abdominal tenderness. Laboratory studies reveal a leukocyte count of 13,200/µL (13.2 m 109/L), total bilirubin 12.4 mg/dL (212 µmol/L), alkaline phosphatase 748 U/L, and CA 19-9 822 U/L. CT scan shows a 3.2-cm lesion in the head of the pancreas with dilation of the pancreatic and bile ducts and multiple lesions throughout the liver that are consistent with metastases. Endoscopic ultrasonography biopsy specimen of the mass is positive for adenocarcinoma. Which of the following is the most appropriate next step in the management of this patient?

Biopsy of a liver lesion

Placement of a metal biliary stent

Radiation to the pancreas and liver lesions

Surgical resection of the pancreatic lesion and adjuvant chemotherapy

The patient's presentation is consistent with pancreatic cancer with metastasis to the liver. The presence of jaundice, elevated bilirubin levels, and dilation of the pancreatic and bile ducts suggest obstruction of the common bile duct. Placement of a metal biliary stent is the most appropriate next step to relieve the obstruction and alleviate symptoms. This can be done endoscopically or percutaneously, and it will improve the patient's quality of life by reducing pruritus and improving appetite. Surgical resection is not appropriate due to the advanced stage of the disease. Radiation therapy may be considered for palliative purposes, but it is not the first-line management for this patient. Biopsy of a liver lesion is not necessary since the endoscopic ultrasonography biopsy of the pancreatic mass already confirmed the diagnosis of adenocarcinoma.

Explanation

The patient's presentation is consistent with pancreatic cancer with metastasis to the liver. The presence of jaundice, elevated bilirubin levels, and dilation of the pancreatic and bile ducts suggest obstruction of the common bile duct. Placement of a metal biliary stent is the most appropriate next step to relieve the obstruction and alleviate symptoms. This can be done endoscopically or percutaneously, and it will improve the patient's quality of life by reducing pruritus and improving appetite. Surgical resection is not appropriate due to the advanced stage of the disease. Radiation therapy may be considered for palliative purposes, but it is not the first-line management for this patient. Biopsy of a liver lesion is not necessary since the endoscopic ultrasonography biopsy of the pancreatic mass already confirmed the diagnosis of adenocarcinoma.

9. Endoscopy shows a 1-cm ulcer in the gastric antrum. If biopsies show mucosa-associated lymphoid tissue (MALT) lymphoma, what is the best initial treatment?

5-FU/cisplatin

Surgical resection

Lansoprazole, amoxicillin, clarithromycin

External beam radiation

The best initial treatment for mucosa-associated lymphoid tissue (MALT) lymphoma is a combination of lansoprazole, amoxicillin, and clarithromycin. This treatment regimen is known as triple therapy and is used to eradicate Helicobacter pylori infection, which is strongly associated with the development of MALT lymphoma. By eradicating the infection, the inflammatory response in the gastric mucosa is reduced, leading to regression of the lymphoma. Surgical resection may be considered if there is no response to triple therapy or in cases of localized disease. 5-FU/cisplatin and external beam radiation are not typically used as initial treatments for MALT lymphoma.

Explanation

The best initial treatment for mucosa-associated lymphoid tissue (MALT) lymphoma is a combination of lansoprazole, amoxicillin, and clarithromycin. This treatment regimen is known as triple therapy and is used to eradicate Helicobacter pylori infection, which is strongly associated with the development of MALT lymphoma. By eradicating the infection, the inflammatory response in the gastric mucosa is reduced, leading to regression of the lymphoma. Surgical resection may be considered if there is no response to triple therapy or in cases of localized disease. 5-FU/cisplatin and external beam radiation are not typically used as initial treatments for MALT lymphoma.

10. A 35-year-old woman is evaluated for a 6-month history of right upper quadrant abdominal pain that has slowly increased in intensity and is worse on deep inspiration. The patient is otherwise well, and her only medication is an oral contraceptive pill that she has taken for 15 years. She drinks alcohol socially but has no history of heavy alcohol use, injection drug use, or blood transfusion. On physical examination, vital signs are normal; BMI is 26. There is slight hepatomegaly with mild discomfort on deep palpation in the right upper quadrant and mid-epigastrium. There is no jaundice or ascites. The lungs are clear. Complete blood count and serum biochemistry studies, including aminotransferases, bilirubin, and α-fetoprotein, are normal. Ultrasonography shows a solitary hyperechoic 9-cm lesion in the right lobe of the liver. CT scan shows a well-demarcated lesion with peripheral enhancement after injection of intravenous contrast; there is no central scar. Liver biopsy specimen reveals sheets of hepatocytes, with no bile ducts or Kupffer cells. Which of the following is the most likely diagnosis?

Focal nodular hyperplasia

Hepatic adenoma

Hepatocellular carcinoma

Simple hepatic cyst

The most likely diagnosis in this case is hepatic adenoma. The patient's history of long-term oral contraceptive pill use is a risk factor for the development of hepatic adenomas. The physical examination findings of hepatomegaly and discomfort on deep palpation in the right upper quadrant are consistent with a hepatic adenoma. The imaging studies, including ultrasonography and CT scan, show a well-demarcated lesion in the liver, which is characteristic of a hepatic adenoma. The liver biopsy specimen also supports the diagnosis, as it reveals sheets of hepatocytes without bile ducts or Kupffer cells, which is consistent with a hepatic adenoma. Focal nodular hyperplasia and hepatocellular carcinoma typically have different imaging and histological features, while a simple hepatic cyst would not cause the symptoms described by the patient.

Explanation

The most likely diagnosis in this case is hepatic adenoma. The patient's history of long-term oral contraceptive pill use is a risk factor for the development of hepatic adenomas. The physical examination findings of hepatomegaly and discomfort on deep palpation in the right upper quadrant are consistent with a hepatic adenoma. The imaging studies, including ultrasonography and CT scan, show a well-demarcated lesion in the liver, which is characteristic of a hepatic adenoma. The liver biopsy specimen also supports the diagnosis, as it reveals sheets of hepatocytes without bile ducts or Kupffer cells, which is consistent with a hepatic adenoma. Focal nodular hyperplasia and hepatocellular carcinoma typically have different imaging and histological features, while a simple hepatic cyst would not cause the symptoms described by the patient.

11. A 25-year-old man is evaluated after being turned down as a blood donor because of abnormal liver chemistry tests. The patient is healthy, takes no medications, does not smoke, and drinks alcohol socially. His parents and siblings are alive and healthy; his maternal grandfather developed type 2 diabetes mellitus at age 75 years. The review of systems is normal. On physical examination, vital signs and BMI are normal. Laboratory studies: Hemoglobin 11.9 g/dL (119 g/L) Mean corpuscular volume 76 fL Cholesterol (total) 155 mg/dL (4.01 mmol/L) LDL cholesterol 85 mg/dL (2.2 mmol/L) HDL cholesterol 33 mg/dL (0.85 mmol/L) Bilirubin (total) 0.5 mg/dL (8.55 µmol/L) Aspartate aminotransferase 25 U/L Alanine aminotransferase 58 U/L Alkaline phosphatase 110 U/L Serologic tests for hepatitis virus infection are normal. Which of the following is the most appropriate diagnostic test for this patient?

Anti-tissue transglutaminase antibody

α1-Antitrypsin concentration

Blood alcohol level

Liver biopsy

The patient's abnormal liver chemistry tests and normal serologic tests for hepatitis virus infection suggest a non-infectious cause for his liver dysfunction. The presence of abnormal liver enzymes, specifically elevated alanine aminotransferase (ALT), suggests hepatocellular injury. Additionally, the patient's low HDL cholesterol and high LDL cholesterol levels are consistent with nonalcoholic fatty liver disease (NAFLD), which is commonly associated with insulin resistance and metabolic syndrome. Given these findings, the most appropriate diagnostic test for this patient is anti-tissue transglutaminase antibody to evaluate for celiac disease, which is associated with both NAFLD and abnormal liver enzymes. Liver biopsy is not indicated at this time as it is an invasive procedure and should be reserved for cases where the diagnosis remains unclear despite initial evaluation.

Explanation

The patient's abnormal liver chemistry tests and normal serologic tests for hepatitis virus infection suggest a non-infectious cause for his liver dysfunction. The presence of abnormal liver enzymes, specifically elevated alanine aminotransferase (ALT), suggests hepatocellular injury. Additionally, the patient's low HDL cholesterol and high LDL cholesterol levels are consistent with nonalcoholic fatty liver disease (NAFLD), which is commonly associated with insulin resistance and metabolic syndrome. Given these findings, the most appropriate diagnostic test for this patient is anti-tissue transglutaminase antibody to evaluate for celiac disease, which is associated with both NAFLD and abnormal liver enzymes. Liver biopsy is not indicated at this time as it is an invasive procedure and should be reserved for cases where the diagnosis remains unclear despite initial evaluation.

12. A 72-year-old man has a 6-week history of epigastric discomfort that is not relieved with over-the-counter antacids. He does not have fever, heartburn, jaundice, or change in bowel habits but believes that his clothes are becoming loose, although he has not weighed himself recently. The patient has a 15-year history of hypertension, treated with a thiazide diuretic, and a several-month history of type 2 diabetes mellitus, treated with an oral hypoglycemic agent. He also takes a statin and low-dose aspirin. Physical examination reveals a thin, elderly man who appears uncomfortable. Vital signs and abdominal examination are normal. There is no scleral icterus. Laboratory Studies Hemoglobin 11.8 g/dL Glucose 145 mg/dL Total bilirubin 2.8 mg/dL Aspartate aminotransferase 35 U/L Alanine aminotransferase 48 U/L Alkaline phosphatase 350 U/L Amylase 140 U/L Which of the following diagnostic studies is most appropriate at this time?

Endoscopic retrograde cholangiopancreatography

Endoscopic ultrasonography

Helical CT scan of the abdomen

Mesenteric angiography

The most appropriate diagnostic study at this time is a helical CT scan of the abdomen. This is because the patient's presentation with epigastric discomfort, weight loss, and elevated liver enzymes suggests a possible pancreatic malignancy. A helical CT scan of the abdomen can help evaluate the pancreas for any abnormalities, such as a tumor. Endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasonography (EUS) are invasive procedures that are typically reserved for further evaluation or intervention after a pancreatic mass has been identified. Mesenteric angiography is not indicated in this case as there are no signs or symptoms suggestive of mesenteric ischemia.

Explanation

The most appropriate diagnostic study at this time is a helical CT scan of the abdomen. This is because the patient's presentation with epigastric discomfort, weight loss, and elevated liver enzymes suggests a possible pancreatic malignancy. A helical CT scan of the abdomen can help evaluate the pancreas for any abnormalities, such as a tumor. Endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasonography (EUS) are invasive procedures that are typically reserved for further evaluation or intervention after a pancreatic mass has been identified. Mesenteric angiography is not indicated in this case as there are no signs or symptoms suggestive of mesenteric ischemia.