Synopsis
Recognise polyarteritis nodosa as a medium-artery necrotising vasculitis causing renal, gastrointestinal, skin, nerve and testicular ischaemia, distinguish it from small-vessel ANCA disease, and coordinate angiographic, biopsy and hepatitis-directed treatment.
- PAN is necrotising vasculitis of muscular medium and small arteries, producing renal-vascular, gastrointestinal, skin, nerve, muscle and testicular ischaemia without primary glomerulonephritis or pulmonary capillaritis.
- Look for fever, weight loss, livedo, tender nodules, ulcers, myalgia, mononeuritis multiplex, severe hypertension, abdominal pain after meals, GI bleeding and testicular pain.
- Urinalysis is often bland or shows non-glomerular abnormalities; red-cell casts or pulmonary haemorrhage should redirect toward AAV, anti-GBM or immune-complex disease.
- Test HBsAg, anti-HBc and HBV DNA early because HBV-associated PAN needs antiviral-led specialist treatment and limited rather than prolonged immunosuppression.
- Use CTA or MRA to identify renal, mesenteric and hepatic stenoses, occlusions, infarcts and microaneurysms; catheter angiography is the anatomical reference when intervention or high-resolution assessment is required.
- Biopsy accessible symptomatic skin, muscle, nerve or testis when safe, seeking transmural necrotising arteritis and avoiding blind sampling of unaffected tissue.
- Severe idiopathic PAN receives high-dose glucocorticoid plus cyclophosphamide; non-severe disease may use glucocorticoid with another steroid-sparing agent under specialist care.
- HBV-PAN treatment combines potent antiviral therapy, a short glucocorticoid course and often plasma exchange in expert care, avoiding prolonged immunosuppression that sustains viral replication.
- Manage mesenteric infarction, aneurysm rupture, coronary disease and critical limb ischaemia with surgical, interventional and vascular teams in parallel.
- ANCA testing is usually negative and not a diagnostic criterion; diagnosis rests on the medium-artery phenotype, imaging or biopsy and exclusion of infection and mimics.
Key red flags
Severe pain out of proportion, guarding, lactate rise or GI bleeding may indicate mesenteric infarction or perforation and requires immediate surgical and vascular imaging.
Abrupt hypertension, AKI or flank pain suggests renal-artery ischaemia or infarction; glomerular casts instead argue against classic PAN.
New foot or wrist drop with painful asymmetric deficits indicates nerve infarction and needs urgent disease control.
Chest pain, troponin rise, arrhythmia or heart failure may indicate coronary arteritis and requires acute cardiology.
HBsAg positivity changes treatment toward antiviral and specialist immune-complex management rather than prolonged conventional immunosuppression alone.
Postprandial or severe acute abdominal pain, bleeding and peritonism signals bowel arterial injury and possible infarction.
Painful asymmetric sensory loss followed by foot or wrist drop reflects sequential nerve-artery infarction.
Investigation priorities
Assess inflammation, ischaemic organ injury and whether urine suggests a small-vessel glomerulonephritis alternative.
Management branches
Painful skin, nerve, renal-vascular, bowel or testicular features suggest PAN.
- Assess organ threat and map pulses, pressure, skin, nerve, abdominal and testicular findings, urine and cardiopulmonary absence or presence.
- Test hepatitis and infection, obtain CTA or MRA of involved territories and select accessible deep tissue for biopsy.
- Use catheter angiography when fine anatomy or embolisation is required and do not delay surgery for suspected bowel necrosis.