Amyloidosis

Question 1

Define:

Answer 1

Heterogeneous group of diseases characterised by extracellular deposition of amyloid fibrils

Question 2

Aetiology/Risk factors:

Answer 2

Can be systemic or localised e.g. in the pancreatic islets (T2DM), cerebral cortex (alzheimer’s), blood vessels (amyloid angiopathy) and in bones and joints.

Type AA - this is from increased amounts of inflammation as amyloid is an acute phase protein. Deposits in Kidney, spleen and liver

Type AL- deposits in heart, kidneys, nerves, gut and vascular

Type ATTR - familial - renal, cardiac and autonomic/sensory neuropathy

Question 3

Epidemiology:

Answer 3

AA - 1-5% of those with an inflammatory condition will develop amyloidosis

AL - 300-600 cases in the UK

ATTR - make up 5% of amyloidosis cases

Question 4

Signs and symptoms:

Answer 4

Renal - renal failure, proteinuria, nephrotic syndrome

Cardiac - restrictive cardiomyopathy, angina, arrythmias, heart failure

GI - malabsorption, weight loss, macroglossia, bleeding, hepatosplenomegaly

Nerves- sensory, motor and autonomic neuropathy, carpal tunnel

Skin - waxy skin, easy bruising, purpura around eyes, plaques and nodules

joints - painful asymmetrical joints

haematological - easy bleeding

Question 5

Investigations:

Answer 5

Urine - proteinuria + free Ig light chains

Bloods - CRP/ESR, rheumatoid factor, Ig levels, serum protein electrophoresis, LFT’s and U + E’s

SAP scan - radio labelled SAP will localise the deposits of amyloid

Tissue biopsy