The following cases and commentary, which address acute pancreatitis, are excerpted from ACP's Medical Knowledge Self- Assessment Program (MKSAP14).
Case 1: Acute-onset abdominal pain in a patient with controlled diabetes
A 51-year-old woman is hospitalized because of the acute onset of moderately severe, constant upper abdominal pain associated with nausea and vomiting. She has type 2 diabetes mellitus controlled with an oral hypoglycemic agent. Other medications are a statin and low-dose aspirin.
On physical examination, the patient is obese. Temperature is normal. There is moderate upper abdominal tenderness without rebound. Laboratory values are as follows: serum total bilirubin, 0.8 mg/dL (13.68 µmol/L); serum aspartate aminotransferase, 180 U/L; serum alanine aminotransferase, 285 U/L; serum alkaline phosphatase, 152 U/L; serum amylase, 1010 U/L; and serum lipase, 950 U/L.
Symptomatic treatment for pancreatitis is begun with intravenous fluids and pain management as needed. On evaluation 12 hours later, the patient has minimal symptoms. Repeated laboratory studies are as follows: serum total bilirubin, 0.9 mg/dL (15.39 µmol/L); serum aspartate aminotransferase, 82 U/L; serum alanine aminotransferase, 100 U/L; serum alkaline phosphatase, 130 U/L; serum amylase, 580 U/L; and serum lipase, 410 U/L.
Which of the following is the most appropriate next step in managing this patient?
A. Abdominal ultrasonography
B. Cholescintigraphy (HIDA scan)
C. Endoscopic retrograde cholangiopancreatography
D. Laparoscopic cholecystectomy
Case 2: Pancreatitis
A 42-year-old woman is hospitalized because of pancreatitis. On physical examination, the patient appears ill and dehydrated. Temperature is 37.6°C (99.6°F), pulse rate is 110 beats/minute, respiration rate is 19 breaths/minute, and blood pressure is 120/90 mm Hg. Abdominal examination discloses diffuse tenderness without rebound.
Laboratory values are as follows: hematocrit, 54%; plasma glucose, 290 mg/dL (16.1 mmol/L); serum triglycerides, 1482 mg/dL (16.73 mmol/L); serum total bilirubin, 0.9 mg/dL (15.39 mmol/L); serum aspartate aminotransferase, 220 U/L; serum alkaline phosphatase, 110 U/L; serum lactate dehydrogenase, 540 U/L; serum amylase, 62 U/L; serum lipase, 250 U/L; and moderately elevated serum C-reactive protein.
The patient is given narcotics as needed for pain control. A CT scan of the abdomen performed three hours after admission shows marked pancreatic edema and diffuse peripancreatic stranding.
In addition to continuing pain relief as needed, which of the following is the most appropriate next step in managing this patient?
A. Intravenous hyperalimentation
B. Vigorous intravenous hydration
C. Endoscopic ultrasonography
D. Endoscopic retrograde cholangiopancreatography
Case 3: Severe abdominal pain in a patient with poorly controlled diabetes and hypertension
A 48-year-old man is hospitalized because of acute severe upper abdominal pain associated with nausea and vomiting. The patient has mild hypertension and poorly controlled type 2 diabetes mellitus (his most recent hemoglobin A1C measurement was 10%). Medications are glyburide, hydrochlorothiazide, an angiotensin-converting enzyme inhibitor, a statin and low-dose aspirin, all of which he has been taking for three years. He does not drink alcoholic beverages and has no recent history of abdominal trauma. There is no family history of pancreatic disease.
Physical examination discloses only mild epigastric tenderness to palpation without rebound. Laboratory values are as follows: plasma glucose, 320 mg/dL (17.76 mmol/L); serum calcium, 9.1 mg/dL (2.27 mmol/L); serum phosphorus, 3.9 mg/dL (1.26 mmol/L); serum total bilirubin, 0.1 mg/dL (1.71 µmol/L); serum aspartate aminotransferase, 48 U/L; serum alanine aminotransferase, 61 U/L; serum alkaline phosphatase, 128 U/L; serum amylase, 125 U/L; and serum lipase, 390 U/L.
Abdominal ultrasonography shows a normal gallbladder without stones, mild fatty liver disease, and normal bile duct diameter. The pancreas is not well visualized. A CT scan of the abdomen shows marked peripancreatic stranding with a small amount of fluid around the tail of the pancreas.
Which of the following diagnostic studies should be done next?
A. Thyroid function tests
B. Serum triglyceride measurement
C. Repeat transabdominal ultrasonography
D. Endoscopic ultrasonography
Answers and commentary
Correct answer: A. Abdominal ultrasonography
This patient has the classic presentation of acute gallstone pancreatitis with markedly abnormal liver chemistry studies (including serum aminotransferase values) and pancreatic enzyme values that rapidly return toward normal. Abdominal ultrasonography may be required to exclude cholelithiasis rather than CT scanning and should be done to verify the diagnosis because a CT scan may not detect gallstones or sludge. Cholescintigraphy (HIDA scan) may demonstrate cystic duct obstruction indicative of chronic cholecystitis but will not show gallstones. Endoscopic retrograde cholangiopancreatography is indicated if the patient's liver chemistry tests become significantly abnormal, especially if jaundice develops and abdominal ultrasonography shows ductal dilatation. Since the relapse rate for gallstone pancreatitis is high, laparoscopic cholecystectomy should be performed before hospital discharge but should not be done until diagnostic studies are obtained.
- Patients with acute gallstone pancreatitis present with elevated serum aminotransferase values and pancreatic enzyme values that rapidly return toward normal.
Correct answer: B. Vigorous intravenous hydration
This patient has hyperlipidemic pancreatitis with several laboratory findings indicative of a poor prognosis (elevated glucose, aspartate aminotransferase, and lactate dehydrogenase levels). She is markedly volume depleted (as indicated by the elevated hematocrit value), which is also a poor prognostic sign. Vigorous hydration is critical in order to maximize pancreatic perfusion and thus possibly reduce the number of subsequent complications.
Intravenous hyperalimentation is inappropriate because a patient with severe pancreatitis requires enteral, rather than parenteral, nutritional supplementation. Endoscopic ultrasonography is usually done to exclude common bile ducts stones in a patient with acute pancreatitis. However, stones are unlikely to be present in someone with hyperlipidemic pancreatitis. Likewise, endoscopic retrograde cholangiopancreatography is appropriate for diagnosing suspected common bile duct stones and cholangitis in a patient with severe biliary pancreatitis but not with hyperlipidemic pancreatitis.
- Marked volume depletion is a poor prognostic sign in a patient with acute pancreatitis.
- Vigorous hydration is critical in a patient with acute pancreatitis and marked volume depletion in order to maximize pancreatic perfusion and reduce subsequent complications.
Correct answer: B. Serum triglyceride measurement
This patient presents with acute pancreatitis of undetermined cause. He may have hypertriglyceridemia because of his poorly controlled diabetes mellitus. In addition, the normal serum amylase value may be a clue to the presence of an elevated serum triglyceride level because hypertriglyceridemia affects the accuracy of the amylase assay and may cause false-negative results. However, this patient's serum triglyceride level was not assessed initially and should be done now.
Hyper- or hypothyroidism is not a cause of acute pancreatitis, and thyroid function tests are therefore not indicated. The initial abdominal ultrasound examination showed no gallstones or sludge. Assuming that the original study was of good quality, a repeat examination is not indicated at this time. Although endoscopic ultrasonography is more sensitive than transabdominal ultrasonography for detecting gallbladder stones and sludge, hyperlipidemia should be excluded before more invasive studies are done.
- A patient with acute pancreatitis should be evaluated for the presence of hypertriglyceridemia.