Background/Purpose: ANCA-associated vasculitis (AAV) sometimes presents mononeuritis multiplex which worsens the prognosis and activity of daily living in patients. This study aimed to determine theprognostic factorsand clinical feature of mononeuritis multiplex associated with AAV.

Methods: Consecutive patients with AAV who visited Tokyo Medical Center between April 2006 and February 2020 were included in this study. We examined the following clinical features: prevalence of neuropathy, age of onset, sex, the worst blood test values before the initial therapy (WBC, Eo, MPO-ANCA, PR3-ANCA, and CRP levels), MMT score of 20 muscles (Max 100 points), and time (days) from the initial neuropathy to the initial induction therapies. Fisher’s exact test, univariate analysis of variance, and logistic regression analysis were applied for evaluation of the risk.

Results: A total of 89 patients with AAV were identified. Among them, 19 patients had eosinophilic granulomatosis with polyangiitis (EGPA) (8 males and 11 females, mean age 59.3 ± 22.0), 9 patients had granulomatosis with polyangiitis (GPA) (0 males, 9 females, meanage 75.6 ± 3.9), and 61 patients had microscopic polyangiitis (MPA) (17 males, 44 females, mean age 78.2 ± 1.5). Of the 89 AAV patients, 26 had sensory neuropathy (15/19 EGPA (78.9%), 11/61 MPA (18.0%), and 0/9 GPA (0%)). Motor neuropathy was observed in 19 patients (EGPA 14/19 (73.7%), MPA 5/61 (8.2%), GPA 0/9 (0%)). 15 patients had both sensory and motor neuropathies (EGPA 12/19 (63.2%), MPA 3/61 (4.9%), GPA 0 (0%)).In patients with both sensory and motor neuropathy, sensory impairment preceded in all cases. AmongThe time from initial sensory neuropathy to initial induction therapy in patients with and without motor neuropathy was 34 ± 10.1 days and 30 ± 10.8 days (p = 0.77) respectively. Also, when comparing those who were treated within 3 days from the onset of motor neuropathy with those who were treated later, MMT score two weeks after the start of treatment were 92.15 ± 1.47 vs. 91.25 ± 2.65 (p = 0.77).

Between the patients with EGPA with and without sensory neuropathy, there were no significant differences in the following: highest WBC（19620.0 ± 2082.6 vs. 19350.0 ± 4033.5 cells/uL (p = 0.953)）, highest Eo（10790.6 ± 1774.8 vs 12440.8 ± 3436.9 cells/uL (p = 0.6750)）, and highest CRP levels (4.46 ± 0.96 vs 2.70 ± 1.85 mg/dL (p = 0.41)) before the initial therapy. On the other hand, comparing the EGPA patients with and without motor neuron disorder, CRP levels were significantly higher in those with motor impairment than those without（WBC 20978.6 ± 2049.8 vs. 15600.0 ± 3429.9 cells/uL (p = 0.20); Eo 12213.4 ± 1775.5 vs. 8127.0 ± 2971.0 cells/uL (p = 0.25); CRP 5.13 ± 0.89 vs. 1.20 ± 1.48 mg/dL (p = 0.04)）. And in patients with motor neuropathy, the decrease in MMT score was significantly correlated with the worst levels of CRP（p = 0.001）while the decrease was not correlated with the other blood tests. In similar analyses of patients with MPA, there were no significant findings.

Conclusion: Worst CRP levels before the initial therapy are a poor prognosis factor for motor neuropathy in patients with EGPA. EGPA patients with high CRP levels need to be paid more attention to because of possible development of motor neuropathy.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/prognostic-factors-for-mononeuritis-multiplex-associated-with-anca-associated-vasculitis/