What is the best method for confirming amyloidosis
Ref Robbins 9/e p262 Amyloidosis may be an unsuspected finding at autopsy in a patient who has no apparent related clinical manifesta- tions, or it may be responsible for serious clinical dysfunc- tion and even death. The clinical course depends on the paicular sites or organs affected and the severity of the involvement. Nonspecific complaints such as weakness, fatigue, and weight loss are the most common presenting manifestations. Later in the course, amyloidosis tends to manifest in one of several ways: by renal disease, hepato- megaly, splenomegaly, or cardiac abnormalities. Renal involvement giving rise to severe proteinuria (nephrotic syndrome) (Chapter 13) often is the major cause of symp- toms in reactive systemic amyloidosis. Progression of the renal disease may lead to renal failure, which is an impor- tant cause of death in amyloidosis. The hepatosplenomeg- aly rarely causes significant clinical dysfunction, but it may be the presenting finding. Cardiac amyloidosis may mani- fest as conduction disturbances or as restrictive cardiomy- opathy (Chapter 10). Cardiac arrhythmias are an impoant cause of death in cardiac amyloidosis. In one large series, 40% of the patients with AL amyloid died of cardiac disease. The diagnosis of amyloidosis may be suspected from the clinical signs and symptoms and from some of the findings mentioned; however, more specific tests must often be done for definitive diagnosis. Biopsy and subsequent Congo red staining is the most impoant tool in the diag- nosis of amyloidosis. In general, biopsy is taken from the organ suspected to be involved. For example, renal biopsy is useful in the presence of urinary abnormalities. Rectal and gingival biopsy specimens contain amyloid in as many as 75% of cases with generalized amyloidosis. Examination of abdominal fat aspirates stained with Congo red is a simple, low-risk method. In suspected cases of AL amyloi- dosis, serum and urinary protein electrophoresis and immunoelectrophoresis should be performed. Bone marrow examination in such cases usually shows plasma- cytosis, even if skeletal lesions of multiple myeloma are not present. Proteomic analysis of affected tissue is now being widely used for detection of small amounts of amyloid (from fat aspirates) and for definitive identification of the type of amylo
Colonoscopy
Sigmoidoscopy
Rectal biopsy
Tongue biopsy
General anatomy