Polyarteritis nodosa

Background/Epidemiology

  • Inflammation of medium sized vessels.  Rare (incidence ~2:1000000, although some report much higher ~3-5/100000); Peak age between 40-50; male preponderance (2:1)
  • Hepatitis B seems to be an important risk factor

Presentation

  • Systemic features e.g. fever, myalgia, arthralgia and weight loss
  • Multisystem disease processes
    • Skin: Palpable purpura, ulceration, livedo reticularis
    • Nervous: peripheral neuropathy (commonly causing both sensory and motor dysfunction)
    • Renal: nephrotic syndrome; hypertension; impaired renal function/AKI (NB Nephritis is rare cf MPA)
    • Gastrointestinal: post-prandial abdominal pain (ischaemia); rarely necrosis and perforation

Investigations

  • Routine investigations
    • Elevated PV/ESR
    • Leucocytosis, normochromic/normocytic anaemia, thrombocytosis
    • Elevated creatinine/low eGFR
    • Mild proteinuria
    • Elevated LFTs
    • NOTE that ANCA serology is not necessary for the investigation (although it may be measured as part of investigations into other causes)
      • Only 30% are ANCA positive and most are p-ANCA
    • Hepatitis B screen
  • Angiography
    • Multiple aneurysms and smooth narrowing of mesenteric, hepatic or renal systems
  • Muscle/sural nerve biopsy
    • Necrotising arteritis with mixed cellular infiltrate
    • Axonal degeneration/fibre loss

Management

  • High dose steroids and immunosuppressants
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