Macroamylasemia: A Simple Stepwise Approach

Typically, macroamylasemia is a condition of elevated serum amylase in the absence of symptomatic disease. However, in the presence of symptoms, especially of abdominal origin, it is important that this condition be identified accurately in order to avoid unnecessary treatment for pancreatitis or other related diseases. This report offers a review of the literature, a case example, and an algorithm for systematically considering the diagnosis of macroamylasemia. (J Am Bd Fam Pract 1989; 2:279-82.) The typical presentation of acute pancreatitis includes an elevated serum amylase level and steady, severe upper abdominal pain radiating to the back. It is often accompanied by nausea and vomiting. Abdominal radiographs can show an enlarged duodenum, a sentinel loop, or pancreatic calcification. Hospitalization is almost always required, and the patient is fed intravenously with or without nasogastric suctioning. Successful therapy is determined by decreased clinical symptoms and a decrease in the amylase level. Few other diseases rely so heavily on a single laboratory value for diagnosis and assessment of therapy. It is essential, therefore, that the family physician be familiar with some of the other common non pancreatic causes of an elevated level of serum amylase, in particular, macroamylasemia (Tables 1, 2) in order to avoid diagnostic confusion, needless hospitalization, and delayed or inappropriate treatment. We present a case example and discussion of macroamylasemia, one of the common nonpancreatic causes of an elevated level of serum amylase. Macroamylasemia is not a disease in itself but a condition associated with hyperamylasemia. We also include an algorithm to assist in a stepwise approach to diagnosis of this condition and to avoid its misdiagnosis as pancreatic disease. Case Report A 58-year-old black man was evaluated in the emergency department because of right flank From the Family Practice Residency Program, Bayfront Medical Center, St. Petersburg, Florida. Address reprint requests to David Parrish, M.D., 500 Seventh Street South, St. Petersburg, FL 33701. pain thought originally to be from pancreatitis. His medical history and review of systems were pertinent for alcoholism. The patient admitted to heavy drinking and had attended Alcoholics Anonymous meetings while living in another area of the country. He stated that he had to stop drinking because of recurrent blackouts and gastrointestinal bleeding, which were believed to be from esophageal varices. The patient was not working and lived with a woman friend. One daughter had sickle cell anemia, but there was no family history of alcoholism. According to the patient and to reliable, though estranged, family members, he had not drunk alcohol for almost 2 years prior to the presenting illness. On examination, the patient was well developed, slim, and in no acute distress. He had mild right costovertebral angle tenderness, but his abdomen was soft and nontender. Initial laboratory tests showed that the amylase level was 573 U/L (310 somogyi units/dL) (normal range 30 to 110 U/L). Liver function tests were normal, and blood urea nitrogen and creatinine were 11 mgldL 0.9 mmol/L) (normal range 7 to 18 mg/dL) and 0.9 mgldL (79.6 f.,Lmol/L) (normal range 0.5 to 1.2 mg/dL), respectively. To confirm the provisional diagnosis of alcoholic pancreatitis, his test for serum lipase was 47 U/L (0.17 f.,L/mL) (normal range 22 to 208 U/L). Computed tomography scan of the abdomen showed no pseudocyst and a normal-appearing pancreas, spleen, and liver; however, there were stones in the gall bladder without dilated ducts. Because the chest radiograph showed a large cavitary lesion (pneumatocele) in the right lung, the patient was hospitalized. The pneumatocele was believed to be caused by regurgitation and aspiration, the result of an esophageal stricture