Amyloidosis

Question 1

Define amyloidosis.

Answer 1

Any histological tissue specimen that binds the cotton wool dye, Congo red, and demonstrates green birefringence when viewed under polarised light is, by definition, an amyloid deposit. The patient with this deposit has amyloidosis. Deposits of amyloid may be localised 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.

Question 2

Explain the aetiology/risk factors of amyloidosis.

Answer 2

Monoclonal gammopathy of undetermined significance (MGUS)
Inflammatory polyarthropathy
Chronic infections
Inflammatory bowel disease
Familial periodic fever syndromes

Question 3

Summarise the epidemiology of amyloidosis.

Answer 3

In the UK, the age-adjusted incidence is between 5.1 and 12.8 per 1 million per year, with around 60 new cases annually.

Question 4

Recognise the presenting symptoms of amyloidosis. Recognise the signs of amyloidosis on physical examination.

Answer 4

Fatigue
Weight loss
Dyspnoea on exertion
Jugular venous distention
Lower extremity oedema

Question 5

Identify appropriate investigations for amyloidosis and interpret the results.

Answer 5

Serum immunofixation - positive in 60% of patients with amyloidosis
Urine immunofixation - positive in 80% of patients with amyloidosis
Immunoglobulin free light chain assay - >95% sensitivity
Bone marrow biopsy - done on all patients with suspected amyloidosis