A 52‐year‐old previously healthy man with history of prior alcohol dependence and a Billroth II procedure 25 years ago for peptic ulcer disease presented with 100 pounds of unintentional weight loss associated with new‐onset diarrhea over the past 6 months. His diarrhea was postprandial, occurring 20–30 minutes after all meals. Physical exam was notable for BMI of 15, orthostatic hypotension, and global muscle wasting. Laboratory studies were significant only for thrombocytosis. Stool studies were negative for infection. Initial testing for HIV, autoimmune and endocrine disease, and age appropriate cancer screenings were unremarkable. Imaging of the chest, abdomen, and pelvis identified SMV with splenic vein thrombosis and pancreatic atrophy, but no mass lesion. A definitive diagnosis of light‐chain amyloidosis (AL type) was ultimately made with Congo red stain and biochemical tests of a duodenal biopsy specimen and bone marrow aspirate.
Unintentional weight loss is a common presenting complaint that hospitalists encounter with a broad differential diagnosis including gastrointestinal, endocrine, cardiovascular, malignant, metabolic, connective tissue, neurologic, infectious, and mental health causes. Comprehensive evaluation can be lengthy and expensive, though clues in the history and physical help guide targeted testing. Amyloidosis is an uncommon cause of unintentional weight loss that presents with variable clinical features because numerous amyloid fibril types exist, which require divergent treatments. Amyloidosis occurs when misfolded proteins are unusually robust; making them resistant to normal proteolytic degradation. They aggregate into amyloid fibrils that alter the function of normal cellular tissues. The disease process can be systemic or localized, and classifications are now based on chemical composition, rather than prior primary or secondary characterization. Biopsy of an abdominal wall fat pad is often not sensitive enough to identify not only the presence, but the type of amyloid; therefore necessitating biopsy of an affected organ. Light‐chain amyloidosis (AL) is the most common systemic form and is related to multiple myeloma (MM). AL typically affects the heart, kidney, peripheral nervous system, and gastrointestinal tract. Treatment modalities for AL mirror those for MM. AL carries the poorest prognosis of any subtype with median survival around 12 months, although early diagnosis and treatment initiation improve life expectancy.
Amyloidosis is a rare cause of unintentional weight loss that carries a poor prognosis. Testing for amyloidosis should be considered in any patient whose initial broad weight loss evaluation has been nondiagnostic. Although abdominal fat pad biopsy may establish a preliminary diagnosis, biopsy of an affected organ is usually needed for confirmation and characterization of the subtype that will guide treatment.
To cite this abstract:Larson J. 100 Pounds of Unintentional Weight Loss: An Old Foe with a New Presentation. Abstract published at Hospital Medicine 2013, May 16-19, National Harbor, Md. Abstract 377. https://www.shmabstracts.com/abstract/100-pounds-of-unintentional-weight-loss-an-old-foe-with-a-new-presentation/. Accessed February 18, 2019.