A vasculitis affecting medium sized arteries with necrotising inflammation leading to aneurysm formation.

• PAN is more common in middle aged men
• associated with hep-B infection

PC

• fever, malaise, arthralgia
• weight loss
• hypertension
• mononeuritis multiplex, sensorimotor polyneuropathy
• abdominal pain - mesenteric ischaemia
• testicular pain
• livedo reticularis
• hameaturia (renal failure)

Investigations

• perinuclear-antineutrophil cytoplasmic antibodies (ANCA) are found in around 20% of patients with 'classic' PAN
• hepatitis B serology positive in 30% of patients
• Skin biopsy

Differential Diagnosis