Amyloidosis is caused by the deposition of amyloid proteins in tissue and organs. It may have a primary cause, may be inherited, or may be secondary to other diseases.
Immunoglobulin light chain (AL) amyloidosis (also called primary systemic amyloidosis) is the most common type of amyloidosis.
Amyloidosis 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 AL amyloidosis. Biopsy verification of amyloid deposits is essential. Accurate classification of amyloid deposit in tissues is necessary prior to initiating appropriate therapy.
Treatment includes management of resulting clinical syndromes, such as nephrotic syndrome, neuropathy, cardiomyopathy, and conduction disorders.
Treatment for AL amyloidosis is high-dose myeloablative chemotherapy with autologous stem cell transplantation (in selected patients) or systemic therapy, or both.
Amyloidosis is caused by the deposition of amyloid proteins in tissue and organs. Any histologic tissue specimen that binds Congo red and demonstrates green birefringence when viewed under polarized light is, by definition, an amyloid deposit.
Deposits of amyloid may be localized in tissue or part of a systemic process. Progressive deposition of amyloid is disruptive to tissue and organ function and manifests its clinical sequelae by the dysfunction of those organs in which it deposits.
History and exam
Key diagnostic factors
- jugular venous distention
- lower extremity edema
- periorbital purpura
- eyelid petechiae
Other diagnostic factors
- weight loss
- dyspnea on exertion
- peripheral neuropathy
- autonomic neuropathy
- nausea or vomiting
- abdominal cramps
- alternating bowel habit
- lightheaded/orthostatic hypotension
- submandibular salivary gland enlargement
- shoulder pad sign
- diffuse muscular weakness
- Carpal tunnel syndrome
- monoclonal gammopathy of undetermined significance (MGUS)
- inflammatory polyarthropathy
- chronic infections
- inflammatory bowel disease
- familial periodic fever syndromes
- Castleman disease
1st investigations to order
- serum immunofixation
- urine immunofixation
- immunoglobulin free light chain assay
- comprehensive metabolic profile
- 24-hour urine collection
- tissue biopsy
Investigations to consider
- mass spectrometry
- immuno-electron microscopy
- immuno-histochemical studies
- genetic testing
- serum troponin level
- N-terminal pro-B-type natriuretic peptide
- echocardiogram (with tissue Doppler and global longitudinal strain)
- cardiac MRI
- scintigraphy (bone)
immunoglobulin light chain (AL) amyloidosis
secondary (AA) amyloidosis (non-familial)
familial periodic fever syndromes
transthyretin (TTR) amyloidosis
relapsed or refractory AL amyloidosis
- Hypertrophic cardiomyopathy (HCM)
- Membranous glomerulopathy
- Monoclonal gammopathy of undetermined significance (MGUS)-associated neuropathy
- NCCN clinical practice guidelines in oncology: systemic light chain amyloidosis
- Guidelines for high dose chemotherapy and stem cell transplantation for systemic AL amyloidosis: EHA-ISA working group guidelines
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