AA amyloidosis
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Etiology
- chronic suppuration or tissue breakdown
- rheumatoid arthritis (50%)
- ankylosing spondylitis
- Crohn's Disease
- chronic infection
- tuberculosis
- osteomyelitis
- infection in paraplegic patients
- bronchietasis
- familial Mediterranean fever
- Castleman disease
- lymphoma
- vasculitis
Pathology
- amyloid contains protein A, a fragment of serum acute phase protein (SAA)
- amyloid fibrils in AA amyloidosis mostly deposit in liver, spleen & kidneys
- end-stage renal disease is major cause of death (40-60%)
Clinical manifestations
- renal failure (nephrotic syndrome) is most common presentation
- gastrointestinal* (image)[5]
- hepatosplenomegaly
- heart failure[1]
Laboratory
- serum protein electrophoresis: polyclonal gammopathy
- urinalysis: hematuria & pyuria minimal or absent
Diagnostic procedures
- electrocardiogram: low voltage
- renal biopsy
- yellow-green birefringence in polarized light
Differential diagnosis
- AL-amyloidosis
- post-infectious glomerulonephritis
- lupus nephritis:
- low serum complement C3, serum complement C4 & CH50
- anti-dsDNA Ab in serum present in high titer
- hematuria, erythrocyte casts in urine
- IgA nephropathy
- microscopic hematuria
- nephrotic syndrome is an unusual presentation
- interstitial nephritis
- pyuria
- proteinuria generally not nephrotic range unless NSAID-induced
Management
- tocilizumab has been used in patients with rheumatoid arthritis[1][5]
- Fibrillex (Neurochem Inc, Phase II/III clinical trials in 2003) <orphan drug status in the U.S. and in Europe>
- poor prognosis: 5 year survival 50%
More general terms
References
- ↑ Jump up to: 1.0 1.1 1.2 Medical Knowledge Self Assessment Program (MKSAP) 11, 18. American College of Physicians, Philadelphia 1998, 2018.
- ↑ http://www.neurochem.com/ResearchActivities.htm
- ↑ Bodin K et al. Antibodies to human serum amyloid P component eliminate visceral amyloid deposits. Nature 2010 Nov 4; 468:93.
- ↑ Obici L, Raimondi S, Lavatelli F, Bellotti V, Merlini G. Susceptibility to AA amyloidosis in rheumatic diseases: a critical overview. Arthritis Rheum. 2009 Oct 15;61(10):1435-40. PMID: https://www.ncbi.nlm.nih.gov/pubmed/19790131 Free Article
- ↑ Jump up to: 5.0 5.1 5.2 Izuka S, Yamashita H Images in Clinical Medicine. Gastrointestinal Amyloidosis. N Engl J Med 2021; 384:2144 PMID: https://www.ncbi.nlm.nih.gov/pubmed/34077646 https://www.nejm.org/doi/full/10.1056/NEJMicm2034179
- ↑ NEJM Knowlege+
Lane T, Pinney JH, Gilbertson JA et al Changing epidemiology of AA amyloidosis: clinical observations over 25 years at a single national referral centre. Amyloid. 2017 Sep;24(3):162-166. PMID: https://www.ncbi.nlm.nih.gov/pubmed/28686088 Clinical Trial.
Lachmann HJ, Goodman HJ, Gilbertson JA et al Natural history and outcome in systemic AA amyloidosis. N Engl J Med. 2007 Jun 7;356(23):2361-71. PMID: https://www.ncbi.nlm.nih.gov/pubmed/17554117 Free article. https://www.nejm.org/doi/pdf/10.1056/NEJMoa070265