Polyarteritis nodosa - Vasculitis

Polyarteritis nodosa

Definition

Polyarteritis nodosa is a rare intense necrotising vasculitis affecting small and mediumsized arteries.

Age

Middle age

Sex

4M : 1F

Aetiology/pathophysiology

Associated with hepatitis B infection in 10–20% because of hepatitis B surface antigen immune complexes. Also associated with hairy cell leukaemia. Transmural neutrophil infiltration of mediumsized arteries occurs, causing degeneration, weakness and microaneurysm formation. Veins are also affected and the condition may result in thrombosis and tissue infarction.

Clinical features

Polyarteritis nodosa is usually an acute illness characterised by calf pain, general malaise, myalgia and weight loss for a few days prior to visceral manifestations:

·        Musculocutaneous: Migratory arthralgia or arthritis, purpura and subcutaneous haemorrhage.

·        Cardiovascular system: Coronary arteritis leading to cardiac arrhythmias, failure and myocardial infarction.

·        Gastrointestinal system: Mesenteric arteritis causing pain, haemorrhage and mucosal ulceration.

·        Genitourinary system: Haematuria, proteinuria, hypertension, renal infarction and renal failure.

·        Nervous system: Polyneuropathy (mononeuritis multiplex) with motor and sensory deficits.

Investigations

Raised ESR and white blood count. Patients are usually p-ANCA positive. Angiography reveals multiple microa-neurysms of the renal or intestinal vessels. Diagnosis may be made on biopsy of affected organs.

Management

Corticosteroids and immunosuppressive agents (e.g. cyclophosphamide) in severe acute cases.