26th February 2025

Medium-vessel vasculitis

Polyarteritis nodosa (PAN)

This is a rare condition; however, questions are relatively common in examinations. 

Systemic features such as fever, weight loss, arthralgia and fatigue are very common. Cutaneous manifestations, including ulcers, livedo reticularis, and purpura, occur in around 50% of patients. Other common features include non-specific abdominal pain, orchitis and mononeuritis multiplex. Up to half of all patients will have some renal involvement, usually renal ischaemia causing hypertension due to activation of the renin-angiotensin-aldosterone pathway. Renal artery aneurysms can also be present.

Antibodies are typically negative, although p-ANCA is sometimes positive. Inflammatory markers can be elevated. Treatment is generally with glucocorticoids, and then steroid-sparing agents such as cyclophosphamide can be used.

There is a correlation with hepatitis B infection, and this should be screened for at diagnosis.

Kawasaki’s disease

This generally occurs in children; however, sequelae can cause morbidity and mortality in the adult population. Classical features include fever over 40 degrees for over 5 days, widespread erythematous rash, strawberry tongue, desquamation to the hands and feet and bilateral conjunctival erythema. The most important complication to be aware of is coronary artery aneurysms, so monitoring with echocardiography is essential. Treatment is with IVIG and aspirin; urgent treatment is important to avoid the development of cardiovascular complications.