Makindo Medical Notes

Related Subjects: |Relapsing Polychondritis |Reactive Arthritis |Raynaud's Phenomenon |Polymyositis |Polyarteritis nodosa |Osteoporosis |Osteogenesis Imperfecta |Osteopetrosis |Polyarteritis nodosa |Rheumatoid Arthritis |Systemic Sclerosis (Scleroderma) |Rheumatology Autoantibodies |Overlap Syndrome |Inclusion Body Myositis |Inflammatory Myopathies |Psoriatic Arthritis |Adult Onset Still's Disease |Alkaptonuria |Behcet's Syndrome

💡 If a systemic vasculitis case is presented with hypertension, renal impairment, and is associated with Hepatitis B, always consider Polyarteritis Nodosa (PAN).

🧾 About

• PAN is a systemic necrotising vasculitis affecting medium and small arteries, usually sparing capillaries and venules.
• Leads to vessel wall inflammation, fibrinoid necrosis, thrombosis, microaneurysms, and tissue infarction.

🧬 Aetiology

• Strongly associated with Hepatitis B virus (HBV) and sometimes cryoglobulinaemia.
• Pathology hallmark: fibrinoid necrosis of vessel walls with inflammatory cell infiltration.

⚠️ Clinical Features

• Constitutional: PUO, fatigue, weight loss, myalgia, arthralgia.
• Neurological: Mononeuritis multiplex (painful, asymmetric motor/sensory deficits due to nerve ischaemia).
• Skin: Palpable purpura, livedo reticularis, subcutaneous nodules.
• Renal: Hypertension, renal impairment, haematuria, proteinuria without glomerulonephritis.
• Gastrointestinal: Abdominal pain (mesenteric ischaemia), risk of bowel infarction, orchitis in men.
• Cardiovascular: Myocardial infarction, pericarditis, and stroke risk increased.

🔬 Investigations

• Bloods: FBC (anaemia, raised WCC), ↑ ESR/CRP.
• Renal function: U&E for renal impairment.
• Hepatitis B serology: Key association.
• ANCA: Typically negative (helps distinguish from microscopic polyangiitis).
• Imaging: Angiography (renal/mesenteric) → “string of beads” microaneurysms.
• Biopsy: Fibrinoid necrosis + transmural inflammation of arteries.

💊 Management

• Multidisciplinary care: Nephrology, rheumatology, infectious diseases.
• Corticosteroids: High-dose steroids are mainstay.
• Immunosuppressants: Cyclophosphamide, azathioprine for severe disease.
• Antivirals: In HBV-associated PAN → antiviral therapy + possible plasma exchange.

Cases — Polyarteritis Nodosa (PAN)

• Case 1 — Systemic vasculitis 💉: A 45-year-old man presents with fever, weight loss, muscle aches, and abdominal pain. Exam: livedo reticularis over the thighs and tender nodules along medium-sized arteries. Labs: raised ESR/CRP, negative ANCA. Angiography: multiple microaneurysms of renal and mesenteric arteries. Diagnosis: classic systemic PAN. Managed with high-dose corticosteroids and cyclophosphamide.
• Case 2 — Renal involvement 🩸: A 52-year-old woman reports new-onset hypertension and haematuria. Exam: reduced renal function, BP 180/100 mmHg. Biopsy: necrotising arteritis of medium-sized renal arteries, no glomerulonephritis. Diagnosis: PAN with renal artery involvement. Managed with immunosuppression and blood pressure control.
• Case 3 — Hepatitis B–associated PAN 🦠: A 39-year-old man with chronic hepatitis B develops abdominal pain, mononeuritis multiplex (wrist and foot drop), and testicular pain. Angiography: aneurysms in mesenteric arteries. Diagnosis: HBV-associated PAN. Managed with antivirals, corticosteroids, and plasma exchange.

Teaching Point 🩺: Polyarteritis Nodosa is a necrotising vasculitis of medium-sized arteries. It classically spares the lungs, is ANCA-negative, and can cause systemic, renal, neurological, and gastrointestinal disease. Always check for hepatitis B association.