Amyloidosis in chronic inflammatory disease — Rapid

Synopsis

Detect AA amyloidosis in chronic inflammatory disease, confirm and type deposits rather than assuming their precursor, suppress serum amyloid A production through cause-specific control, and protect kidney and systemic function through coordinated specialist care.

AA amyloidosis is a complication of prolonged serum amyloid A elevation from inflammatory, autoinflammatory or infectious disease; it is not interchangeable with AL amyloidosis.
The common presentation is increasing albuminuria or proteinuria, nephrotic syndrome and progressive kidney impairment in someone with years of inflammatory burden.
First-line detection is urine ACR or PCR, albumin, creatinine and eGFR plus inflammatory activity and serum amyloid A where available; normal symptoms do not ensure low SAA.
Reference diagnosis requires Congo-red-positive tissue and accurate fibril typing, preferably mass spectrometry. Never infer AA type solely from rheumatoid disease or a negative monoclonal screen.
Screen every suspected case for a monoclonal process with serum and urine immunofixation plus serum free light chains interpreted for kidney function because AL requires urgent clone-directed care.
The disease-modifying first-line principle is sustained control of the source inflammation so SAA remains near normal; a pragmatic expert target is below 10 mg/L when the assay is available.
For FMF, continuous colchicine is first-line even when attacks improve; persistent inflammation or AA risk prompts adherence review, maximum tolerated dose and specialist IL-1 blockade.
Choose biologic treatment for the underlying disease: IL-1 inhibition for appropriate autoinflammatory disease, IL-6 inhibition for selected arthritis, Still or Castleman disease, and antimicrobial source control for infection.
Renal care includes ACE inhibitor or ARB for albuminuria when tolerated, careful salt and loop-diuretic management, vaccination, thrombosis assessment and timely kidney-replacement planning.
There is no routine licensed drug that directly dissolves AA deposits; response is judged by SAA suppression, proteinuria, eGFR, albumin, symptoms and specialist whole-body burden assessment.

Key red flags

Breathlessness, hypoxaemia, rapidly increasing oedema, oliguria or severe hypertension requires urgent evaluation for pulmonary oedema, acute kidney injury and nephrotic fluid complications.

Pleuritic pain, haemoptysis, unilateral leg swelling, sudden abdominal or flank pain and catheter dysfunction raise venous thrombosis, pulmonary embolism or renal-vein thrombosis.

Fever, rigors, hypotension or confusion in nephrotic or immunosuppressed disease requires immediate sepsis treatment because urinary, respiratory, skin and line infection can progress rapidly.

A monoclonal protein, abnormal free-light-chain ratio beyond renal explanation, cardiomyopathy, neuropathy, macroglossia or bruising means AL amyloidosis remains possible until deposit typing is secure.

Rapidly active urine sediment, haematuria, complement consumption or abrupt renal decline is atypical for pure glomerular AA deposition and requires a second renal process assessment.

Persistently high serum amyloid A despite few symptoms indicates ongoing precursor exposure and future deposition risk; symptom control alone is not sufficient.

Nephrotic emergency

Sudden dyspnoea, limb swelling, flank pain, oliguria, infection or hypotension can signal thrombosis, pulmonary oedema, sepsis or acute kidney injury.

Investigation priorities

Urine ACR or PCR and renal profileFirst step

Detect and stage renal involvement.

Management branches

Diagnostic sequenceConfirm deposits, type them, then identify the source

Persistent proteinuria, nephrotic syndrome or organ dysfunction occurs with chronic inflammation.

Quantify urine protein and renal function, measure inflammatory activity and screen urgently for nephrotic complications and atypical urine sediment.
Perform serum and urine immunofixation and free light chains, then obtain the safest informative Congo-red-positive tissue for expert fibril typing.
Only after type is secure, integrate the inflammatory or infectious source and stage kidney and systemic burden through the amyloidosis service.

First-line disease modificationSuppress serum amyloid A continuously

AA type is confirmed and the precursor source is identifiable.

Set a measurable inflammatory target using SAA where available, CRP and disease activity and correct adherence, interaction and infection barriers.
Escalate cause-specific therapy: continuous colchicine for FMF, appropriate targeted DMARD for inflammatory disease, or antimicrobial and procedural source control for infection.
Reassess SAA repeatedly and change strategy if biochemical exposure continues even when symptoms or attack frequency improve.

Key medicines

ColchicineFor adult FMF use 1–1.5 mg orally daily initially, once or divided; increase by 0.5 mg steps according to attacks and SAA to a maximum 3 mg daily if tolerated and specialist supervised.Reduce or avoid in significant renal or hepatic impairment, monitor FBC and CK, and never combine casually with strong CYP3A4 or P-glycoprotein inhibitors such as clarithromycin.

CanakinumabFor an adult weighing at least 40 kg, give 150 mg subcutaneously every four weeks; if response is inadequate, specialist product guidance permits 300 mg every four weeks.Specialist prescribing; screen infection and TB risk, avoid live vaccines, monitor neutrophils and injection reactions, and plan pregnancy individually.

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