Macroamylasemia: A Benign Cause for High Serum Amylase.

Hyperamylasemia is the most common biochemical marker for the diagnosis of acute pancreatitis, but has low specificity. A 9-year-old girl presented to our hospital with complaints of pain abdomen, fever and vomiting for a week. Her serum amylase done elsewhere was 3500 U/ L, and with suspicion for acute pancreatitis, she was referred to our center. On examination, her abdomen was soft with mild tenderness in right iliac area. Her blood investigations indicated a neutrophilia (white blood cell count 13 × 109/L), high serum amylase (4310 U/L), normal serum lipase (32 U/L), and normal serum creatinine. Ultrasonography of abdomen showed mild peri-appendicular edema and normal pancreas. In view of above findings and non-fulfillment of diagnostic criteria for acute pancreatitis [1], patient was managed conservatively as a case of acute appendicitis. At followup after 4 weeks, she was asymptomatic, but her serum amylase continued to be abnormally high (2588 U/L), with normal lipase. Ultrasound and contrast-enhanced computed tomography of abdomen were normal. With no obvious intrabdominal or salivary pathology to explain such high amylase values in absence of renal failure, possibility of macroamylasemia was considered. Amylase creatinine clearance ratio (ACCR) [(urine amylase/serum amylase) × (serum creatinine/urine creatinine)×100] estimation was done which was 0.36 (normal 1-4%), confirming the diagnosis of macroamylasemia.