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# Amyloidosis

Misfolded proteins form insoluble fibres (amyloid) that build up in the heart, kidney, nerves and other organs and make them fail.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Kidneys](https://durgical.com/en/anatomy/kidney/)
- [Liver](https://durgical.com/en/anatomy/liver/)
- [Spleen](https://durgical.com/en/anatomy/spleen/)
- [Tongue](https://durgical.com/en/anatomy/tongue/)
- [Median nerve](https://durgical.com/en/anatomy/median-nerve/)
- [Carpal tunnel](https://durgical.com/en/anatomy/carpal-tunnel/)

## In biochemistry

- [Molecular chaperones and heat shock proteins](https://durgical.com/en/biochemistry/topics/molecular-chaperones-and-heat-shock-proteins/)
- [Proteasome (26S, β5 subunit)](https://durgical.com/en/biochemistry/enzymes/proteasome/)
- [Protein structure and folding](https://durgical.com/en/biochemistry/topics/protein-structure-and-folding/)
- [Plasma proteins and electrophoresis](https://durgical.com/en/biochemistry/topics/plasma-proteins-and-electrophoresis/)
- [Immunoglobulins (antibodies)](https://durgical.com/en/biochemistry/enzymes/immunoglobulins/)
- [Transthyretin (prealbumin)](https://durgical.com/en/biochemistry/enzymes/transthyretin/)

## Why it happens

- [Special stains in diagnosis: Congo red, Prussian blue, PAS, Ziehl–Neelsen, Gram](https://durgical.com/en/general-pathology/special-stains-in-diagnosis-congo-red-prussian-blue-pas-ziehl-neelsen-gram/)
- [Systemic effects of inflammation: fever, acute-phase proteins, leukocytosis, sepsis](https://durgical.com/en/general-pathology/systemic-effects-of-inflammation-fever-acute-phase-proteins-leukocytosis-sepsis/)
- [Endoplasmic reticulum stress and the unfolded protein response](https://durgical.com/en/general-pathology/endoplasmic-reticulum-stress-and-the-unfolded-protein-response/)
- [Chronic inflammation: causes, cells and features](https://durgical.com/en/general-pathology/chronic-inflammation-causes-cells-and-features/)

## What it is

A group of diseases in which a misfolded plasma protein is laid down outside cells as cross-β-sheet fibrils; each type is named after its protein (AL, AA, ATTR…).

## Who gets it

Uncommon. AL is the commonest systemic type in high-income countries; wild-type ATTR is increasingly recognised in older men with heart failure. No Colombia-specific figures were found.

## Causes

- AL: immunoglobulin light chains from a plasma-cell clone (sometimes with myeloma)
- AA: serum amyloid A protein in chronic inflammation (rheumatoid arthritis, tuberculosis, familial Mediterranean fever)
- ATTR: variant (hereditary) or normal (older adults) transthyretin
- Others: β2-microglobulin (long-term dialysis), β-amyloid (Alzheimer, localised), amylin (islets in type 2 diabetes)

## Risk factors

- Monoclonal gammopathy (MGUS, myeloma)
- Chronic inflammatory diseases
- TTR variants and family history
- Older age and male sex (wild-type ATTR)
- Many years of haemodialysis

## Pathophysiology

The precursor protein loses its native shape (from an unstable variant, overproduction or age), exposes segments that stack into β-sheets and forms fibrils that resist breakdown. The fibrils settle in the extracellular matrix with serum amyloid P component and glycosaminoglycans, thicken walls and push cells apart: the myocardium stiffens (restrictive cardiomyopathy), the glomerulus leaks protein (nephrotic syndrome) and nerves are compressed or degenerate. Pre-fibrillar oligomers are toxic too.

## Classification

- AL (light chains)
- AA (serum amyloid A)
- Hereditary ATTR and wild-type ATTR
- Localised (cerebral β-amyloid, amylin, calcitonin in medullary thyroid carcinoma)

## Symptoms and signs

- Breathlessness, oedema and fatigue from heart failure with thick walls
- Foamy urine and oedema from nephrotic syndrome
- Tingling and pain in feet and hands, bilateral carpal tunnel syndrome
- Dizziness on standing, diarrhoea or constipation (autonomic neuropathy)
- Macroglossia and bruising around the eyes (typical of AL)
- Weight loss and hepatomegaly

## Red flags

- Syncope or arrhythmias
- Rapidly progressive heart failure
- Nephrotic-range proteinuria with kidney failure
- Bleeding from factor X deficiency (AL)

## Diagnosis

**Clinical**
Suspect it with heart failure plus thick walls and low voltage, unexplained nephrotic syndrome, neuropathy with bilateral [carpal tunnel](https://durgical.com/en/anatomy/carpal-tunnel/), or macroglossia.

**Tests**
Biopsy (abdominal fat, salivary gland or affected organ) with Congo red: apple-green birefringence under polarised light; typing by immunohistochemistry or mass spectrometry; serum and urine electrophoresis and immunofixation and free light chains; proteinuria, troponin and NT-proBNP; electrocardiogram (low voltage); TTR genetic testing.

**Imaging**
Echocardiography (thick walls, restrictive pattern, strain with apical sparing); cardiac MRI with diffuse late enhancement; technetium pyrophosphate bone scintigraphy for ATTR.

## Treatment

**Medical**
AL: treatment aimed at the plasma-cell clone (proteasome inhibitors, anti-CD38 antibodies, corticosteroids)

**Procedure**
AL: autologous haematopoietic stem cell transplant in selected patients

**Medical**
ATTR: transthyretin stabilisers (tafamidis, acoramidis) or silencers of its synthesis (patisiran, vutrisiran)

**Medical**
AA: control the underlying inflammatory disease (colchicine in familial Mediterranean fever, biologics in rheumatoid arthritis)

**Conservative**
Management of heart and [kidney](https://durgical.com/en/anatomy/kidney/) failure with diuretics and fluid control; some cardiac drugs are poorly tolerated

**Surgical**
Heart, kidney or [liver](https://durgical.com/en/anatomy/liver/) transplant in selected cases

## Complications

- Heart failure and sudden death
- End-stage kidney disease
- Disabling neuropathy
- Orthostatic hypotension

## Prognosis

Depends on the type and on cardiac damage at diagnosis; advanced heart involvement worsens the outlook greatly. Targeted treatments have improved survival.

## Test yourself

Think of the answer, then tap the question to see it.

## Which stain confirms amyloid in a biopsy?

Congo red, which shows apple-green birefringence under polarised light because of the cross-β-sheet structure.

## Which protein does AL amyloid come from, and what is it linked to?

Immunoglobulin light chains from a plasma-cell clone; it is linked to gammopathies and myeloma.

## Which amyloidosis develops in chronic inflammation?

AA, from serum amyloid A, an acute-phase reactant the liver overproduces.

## Which imaging test points to transthyretin cardiac amyloidosis?

Technetium pyrophosphate scintigraphy, which shows intense uptake in ATTR myocardium.

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## Related conditions

- [Multiple myeloma](https://durgical.com/en/conditions/multiple-myeloma/)
- [Prion diseases (Creutzfeldt–Jakob)](https://durgical.com/en/conditions/prion-diseases/)
- [Heart failure](https://durgical.com/en/conditions/heart-failure/)
- [Carpal tunnel syndrome](https://durgical.com/en/conditions/carpal-tunnel-syndrome/)
- [Alzheimer disease](https://durgical.com/en/conditions/alzheimer-disease/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Amyloidosis: MedlinePlus](https://medlineplus.gov/amyloidosis.html) (MedlinePlus, US National Library of Medicine, 2026); [Primary amyloidosis: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000533.htm) (MedlinePlus, US National Library of Medicine, 2026); [Transthyretin amyloidosis: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/transthyretin-amyloidosis/) (MedlinePlus, US National Library of Medicine, 2026); [TTR gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/ttr/) (MedlinePlus, US National Library of Medicine, 2026).

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