📿

Polyarteritis nodosa

💡
Vasculite segmentar de vasos arteriais de médio calibre (arteríolas e artérias)
 
Definição
  • Poliarteritis - means multiple arteries. Prototypical multisystem vasculitis
    • Renal (HTN)
    • Mesenteric (abdominal pain, melena)
    • Hepatic
    • Visceral/gonadal
    • Coronary vessels
    • Adipose tissue - septal panniculitis
    • Lungs are spared
  • Nodosa - segmental fibrinoid transmural necrosis of medium sized arteries, eventually healing with fibrosis producing a “string of pearls” which are hard hence nodosa
 
Etiologia
  • maioria idiopatico
  • Associations
    • Hepatite B
    • Caso na SPDV de associação a tricoleucemia
    • IBD, Group A Strep, HCV, SLE, leukemias, FMF, Cogan’s syndrome (keratitis with vestibular auditory problems)
    • Mutations in CERC1 gene
    • VEXAS syndrome
 
2 formas principais
  • PAN clássica - multissistémica
  • PAN cutânea
    • “Benign” or limited variant of PAN
    • More common in pediatric population
    • Painful nodules with livedo reticularis and ulceration
      • Stellate scarring or atrophie blanche seen
    • Chronic, relapsing
    • Mild constitutional symptoms, myalgia, peripheral neuropathy, orchitis
    • Same associations as PAN
    • P-ANCA may be present
 
Apresentação clínica
  • Cutaneous lesions in 25-65% of cases
    • Vasos médios
      • Nodulos subcutaneos
        • 5mm-1cm subcutaneous nodules along the vessel (painful, pulsatile or ulcerated), livedo reticularis
        • Typically dependent sites (lower extremities)
      • Livedo racemoso
      • Purpura retiforme (aspeto reticulado)
      • Ulceras
      • Necrose se mais distal
  • Manifestações sistémicas
    • Renal: Hypertension, rather than glomerular
    • Mesenteric: abdominal pain, melena
    • Hepatic: edema
    • Visceral/gonadal
    • Coronary vessels: tachycardia
    • Neuronal: Mononeuritis multiplex: foot drop
    • Fever, weight loss
    • Adipose tissue - panniculitis
 
Diagnóstico:
  • No serologic evidence
  • Biópsia
    • “segmental necrotizing vasculitis of medium sized vessels”
    • symptomatic skin, but also muscle, testes, sural nerve
    • Como a vasculite segue o vaso, por vezes é melhor uma biópsia excisional para o patologista seguir o vaso que 1 ou 2 punch
    • Histologia
      • Semelhante nas 2 formas
      • Biópsia deve ser feita na área branca no meio
      • Vasculite necrosante de arteríolas musculares na derme profunda e hipoderme
      • As alterações podem ser focais
      • Necrose fibrinóide (pode destruir a parede muscular e lamina elastica interna
      • Infiltrado misto (neutrófilos, eosinófilos, mononucleares)
      • Se paniculite
        • PMN’s in the wall of septal arterioles and arteries
        • Targetoid appearance: eosinophilic ring of fibrinoid necrosis in the tunica intima
        • Later
          • Mixed inflammatory cells
          • May have thrombi but not predominate
          • DIF: IgM and complement in vessel wall
  • Renal biopsy if active urine sediment
  • angioTC
    • Artérias renais
    • Aneurisma aorta abdominal
  • Urina com sedimento
  • 20% with + p-ANCA
 
Treatment
  • Systemic PAN is life-threatening
    • Cutaneous PAN can be treated with NSAIDs initially
  • Before steroids, survival past 5 years was 15%
  • 1-2mg/kg/day prednisone if visceral involvement
  • May follow ESR for therapeutic response
  • If associated with HBV, poor prognosis
    • IFN with antivirals + plasma exchange shown beneficial
    • Plasma exchange in those without HBV not beneficial