Primary amyloidosis is a disorder in which abnormal proteins build up in tissues and organs. Clumps of the abnormal proteins are called amyloid deposits. Primary amyloidosis can lead to conditions that include:Carpal tunnel syndrome;Heart muscle damage (cardiomyopathy) leading to congestive heart failure;Intestinal malabsorption;Liver enlargement;Kidney failure;Nephrotic syndrome;Neuropathy (nerves that do not work properly);Orthostatic hypotension (abnormal drop in blood pressure with standing);The deposits build up in the affected organs, causing them to become stiff, which decreases their ability to function. An amyloid tissue deposition disease that may have a primary cause or be secondary to other diseases. Usually presents with unexplained weight loss, fatigue, and edema resistant to diuretic therapy. Immunofixation of the serum and urine confirms the presence of monoclonal light chains in primary systemic amyloidosis. Biopsy verification of amyloid deposits is essential. Treatment includes appropriate management of resulting clinical syndromes, such as nephrotic syndrome, cardiomyopathy, and conduction disorders. Definitive treatment of primary systemic amyloidosis (AL amyloidosis) includes myeloablative high-dose chemotherapy with stem cell reconstitution in selected patients, or chemotherapy.