Primary systemic amyloidosis: a cause of malabsorption syndrome

Although malabsorption syndrome is encountered frequently by general internists and gastroenterologists and is common to various underlying disease processes, primary amyloidosis is often overlooked during medical evaluation. We describe the diagnosis, natural history, and laboratory features of a subgroup of patients with primary amyloidosis who presented predominantly with gastrointestinal symptoms and with evidence of a malabsorption syndrome.

We reviewed all patients diagnosed with amyloidosis and malabsorption syndrome who had been seen at the Mayo Clinic from 1960 through 1998. Nineteen patients with small bowel biopsy results showing primary amyloid and with laboratory evidence of a malabsorption syndrome were studied.

The most common symptoms were diarrhea or steatorrhea in 95% of patients (n = 18), anorexia in 42% (n = 8), and dizziness in 32% (n = 6). The most common signs included weight loss in all 19 patients, with a median weight loss of 30 pounds (range, 2 to 134 pounds) and hypotension or orthostatic changes in 10 patients (53%). The median time from symptom onset to diagnosis was 7 months. Most patients had evidence of amyloid involvement of other organs. Only 3 patients (16%) were diagnosed correctly upon initial presentation. Serum or urine protein electrophoresis results were positive in 95% of patients (n = 18). Median survival was 11 months from histologic diagnosis.

Primary systemic amyloidosis should be considered in the differential diagnosis of malabsorption syndrome. All patients over 30 years of age with a malabsorption syndrome should have screening serum and urine immunofixation before undergoing a small bowel biopsy.