Amyloid light-chain amyloidosis presenting as abdominal bloating: a case report

BACKGROUND: We present a case of amyloid light-chain amyloidosis with occult plasma cell dyscrasia, with the rare initial presentation of gastroparesis. While amyloidosis is known to affect the gastrointestinal system, rarely do patients present with gastrointestinal symptoms as their first symptom. To the best of our knowledge, this is the first such case reported with a definitive diagnosis made on gastroscopy. CASE PRESENTATION: A 52-year-old Malay man with abdominal bloating, early satiety, and weight loss was found to have significant gastroparesis. He had a past medical history of stable non-ischemic cardiomyopathy. Results from initial screening were negative for common causes of gastroparesis, such as diabetes or offending medications. Gastroscopy did not show any mechanical gastric outlet obstruction. Our patient subsequently developed symptoms of postural giddiness, which then prompted further investigations for possible autonomic dysfunction. These finally revealed evidence of systemic involvement, including postural hypotension, speckled myocardium with infiltrative cardiomyopathy on a transthoracic echocardiogram, and multifocal motor neuropathy on nerve conduction studies, from which he had been relatively asymptomatic. These findings were collectively suggestive of infiltrative disease. Retrospective Congo red staining of a gastric biopsy specimen confirmed the diagnosis of gastric amyloidosis. The final diagnosis was amyloid light-chain amyloidosis secondary to plasma cell dyscrasia, which was confirmed by bone marrow examination. Our patients was started on chemotherapy and prokinetic agents, with some improvement in gastrointestinal symptoms on follow-up. CONCLUSION: We present this case to highlight that, although rare, gastroparesis can be the initial sole presentation of amyloidosis. It is important for the internist, gastroenterologist, and hematologist to consider amyloidosis as a differential diagnosis in the investigation of gastroparesis and to be vigilant in monitoring for other systemic involvement.