**4. Symptoms and clinical features of the neuropathy in ANCA-associated vasculitis**

PN is usually the first clinical presentation of systemic vasculitis especially in EGPA and MPA. In other cases, the PN is associated with systemic symptoms of the disease such as asthenia, weight loss, fever, arthralgia or arthritis and vascular purpura. PN is characterized by an acute onset of pain, weakness and sensory loss that predominantly affects the distal portion of the extremity. Initially, the PN may present as a mononeuritis evolving over weeks or months later into multifocal neuropathy or mononeuritis multiplex [16]. The pain is described as throbbing and aching rather than burning. The lower limbs are usually affected and the most common involved nerve is the deep peroneal nerve [11–14, 17–22]. In the upper limb, the ulnar nerve is the most common affected nerve [17]. The mononeuritis multiplex pattern evolves into an asymmetrical or symmetrical polyneuropathy pattern, which can progress into a generalized sensorimotor neuropathy [17]. Muscle weakness and atrophy is also variable inially mild but subsequently prominent [23]. Uncommon presentations of PN in AAV are symmetrical polyneuropathy from onset and pure motorneuropathy [17, 24].
