1. Morning Report
10/5/17

2. Neuropathy in vasculitis
Ischemia tends to happen randomly along nerves, affecting longer nerves first and thus can present quite asymmetrically
Mononeuritis multiplex is the most specific presentation for vasculitis; that said, sensorimotor polyneuropathy is also very common and can be asymmetric; it is difficult to distinguish the two without EMG!
Of note, neuropathies in vasculitis tend to be painful

3. Microscopic polyangiitis
Characterized by small vessel necrotizing arteritis, without formation of granulomas.
Often associated with MPO-ANCA (AKA p-anca)
Vessel wall injury is thought to be cell-mediated injury, not immune complex deposition.
Gwathmey KG, Burns TM, Collins MP, Bonham Dyck PJ. Vasculitic Neuropathies. Lancet Neurology. 2014;13(1):67-82

4. Microscopic polyangiitis and neuropathy
About 30-40% of microscopic polyangiitis cases will have evidence of nervous system involvement, typically peripheral neuropathy (can be mononeuritis multiplex or polyneuropathy).
Rare that this is the initial presenting syndrome of the disease (9% of cases)
Zhang W, Zhou G, Shi Q, Zhang X, Zeng F, Zhang C. Clinical analysis of nervous system involvement in the ANCA-associated systemic vasculitides. Clin Exp Rheumatol 2009; 27: S65-S69.

5. ANCA vasculitis-associated myopathy
Mostly just described in case reports as a standalone entity
When both muscle and nerve are biopsied (thought to increase diagnostic yield), 30% of cases both muscle and nerve are found to have evidence of disease, and 30% of time disease is only found in muscle (despite clinical neuropathy). So, probably there is quite a bit of subclinical myopathy in patients with ANCA- associated neuropathy
Said G, Lacroix C. Primary and secondar vasculitic neuropathy. J Neurol ; 252:
Said G, Lacroix C. Primary and secondary vasculitic neuropathy. J Neurol ; 252:

6. Take home points
Vasculitic neuropathies tend to be painful and asymmetric, with associated elevated inflammatory markers
You will not always find mononeuritis multiplex as the clinical presentation. Prominent asymmetry should make you suspicious!