What is the prognosis of idiopathic polyarteritis nodosa (PAN)?

Updated: Dec 17, 2020
  • Author: Dana Jacobs-Kosmin, MD, FACP; Chief Editor: Herbert S Diamond, MD  more...
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Traditionally, it has been taught that relapses of polyarteritis nodosa (PAN) are rare in individuals who completely recover. However, a study in Sweden described 10 patients with PAN, 57% of whom experienced relapse within 5 years. [31]

Recovery from neurologic deficits due to PAN can take up to 18 months. Central nervous system (CNS) involvement carries a worse prognosis than does peripheral nerve involvement. [20]

The prognosis is markedly worse in patients with acute abdominal syndromes characterized by extensive bowel involvement. [32] Multiple perforations may be found, relapses are common, and the postoperative course is complicated by infections and delayed healing. Surgery performed for cholecystitis or appendicitis does not appear to worsen prognosis in the same way.

The prognosis is better in patients with cutaneous PAN without systemic involvement. This disease is benign but tends to relapse. Kato et al reported higher risk of relapse in patients with cutaneous PAN who had pretreatment cutaneous ulcers, elevated C-reactive protein level, higher absolute neutrophil count (> 4.9 × 103/μL) and neutrophil-to-lymphocyte ratio, and higher systemic immune-inflammation index. [33]

In a retrospective study of 52 patients with childhood-onset PAN who were followed for a mean of 6.2 years, 27 patients (51.9%) were in clinical remission without medication at follow-up, 17 (32.7%) were in clinical remission while on medication, and six patients (11.6%) had a persistent or relapsing disease course. Two patients (3.8%) with severe cerebral involvement died. Cranial nerve palsy occurring during the course of disease was significantly correlated with a worse prognosis. Nephrogenic hypertension at disease onset and seizures during the course of the disease were significantly associated with irreversible organ damage. [34]

Relapses were more frequent among PAN patients with severe gastrointestinal involvement in a retrospective study of 69 pediatric patients, while a higher cumulative dose of cyclophosphamide was associated with a lower relapse risk. During follow-up with a median duration of 6 years, the relapse rate was 35%. The mortality rate was 4%. [35]

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