Amyloidosis

Background

• Accumulation of proteins (amyloid fibrils) in tissues
• Heart and kidneys most commonly affected organs
• Causes:
  • Primary amyloidosis, hereditary amyloidosis
  • Secondary (due to systemic inflammatory condition)
  • ESRD-associated (caused by β2-microglobulin amyloids, not filtered out by dialysis membranes))
  • Senile amyloidosis (causes cardiac amyloid)

Clinical Features

Systemic light change amyloidosis: A. Macroglossia with lateral scalloping of the tongue. B. Bilateral periorbital purpura. C. Pseudo athletic appearance secondary to diffuse muscular infiltration. D. Voluminous hepatomegaly due to primary hepatic amyloidosis. E. Diffuse bilateral interstitial lung disease. F. Submandibular gland enlargement. G-H. Localized AL amyloidosis. G. Nodular conjunctival amyloidosis. H. Laryngeal supraglottic amyloid lump.

• Nephrotic syndrome with kidney involvement
• Restrictive cardiomyopathy
• Sensory and autonomic neuropathies (no CNS involvement)
  • Sensory neuropathy: symmetrical pattern, progresses distal to proximal
  • Autonomic neuropathy: orthostatic hypotension or nonspecific GI symptoms
• Hepatomegaly, elevated serum AST and AlkPhos
• Diabetes secondary to pancreatic infiltration
• Macroglossia

Evaluation

• Evaluate for other causes of symptoms
• Diagnosis via fat pad biopsy: apple-green birefringence with Congo red stain

Management

• Varies depending on underlying etiology and organ systems involved