# Vasculitic neuropathy

Vasculitic neuropathy is a peripheral neuropathic disease. In a vasculitic neuropathy there is damage to the vessels that supply blood to the nerves. It can be as part of a systemic problem or can exist as a single-organ issue only affecting the peripheral nervous system (PNS). It is diagnosed with the use of electrophysiological testing, blood tests, nerve biopsy and clinical examination. It is a serious medical condition that can cause prolonged morbidity and disability and generally requires treatment. Treatment depends on the type but it is mostly with corticosteroids or immunomodulating therapies.

## Types

There are three main categories of vasculitic neuropathies: primary, secondary and non-systemic.

### Primary systemic vasculitic neuropathy

Some patients with systemic vasculitis will have their multi-organ disease spread to the peripheral nervous system; this is primary vasculitic neuropathy. Some examples of systemic vasculitic disease are: IgA vasculitis, Hypocomplementemic urticarial vasculitis, polyarteritis nodosa (PAN) and anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitides such as granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA) and microscopic polyangiitis (MPA).

### Vasculitic neuropathy secondary to other disease

Some patients with a non-vasculitic systemic disease or another illness such as infection or malignancy can subsequently develop vasculitic neuropathy as a direct consequence of the former illness; this is secondary vasculitic neuropathy. Some examples of such illness which can cause vasculitic neuropathy are:
* Connective tissue diseases: rheumatoid arthritis, systemic lupus erythematosus, primary sjögren's, dermatomyositis.
* Infectious diseases: hepatitis B, hepatitis C, human immunodeficiency virus (HIV), cytomegalovirus, lyme disease, human T-cell-lymphotrophic virus-I, parvovirus B19.
* Malignancy.
* Drugs (amphetamines, sympathomimetics, cocaine, etc.)
* Vaccinations.

### Non-systemic vasculitic neuropathy

Non-systemic vasculitic neuropathy (NSVN) is a diagnosis of elimination. When no systemic illness can be found, yet evidence of a vasculitic neuropathy exists, a diagnosis of non-systemic vasculitic neuropathy is made. It is a single-organ problem. A nerve biopsy is required in order to make the diagnosis of non-systemic vasculitic neuropathy.
There are distinct subtypes of NSVN with evolving categorisation in the literature. Currently accepted subtypes are:
* 'Classical' distal-predominant NSVN
* Wartenberg migratory sensory neuropathy
* Post-surgical inflammatory neuropathy
* Diabetic radiculoplexus neuropathy (lumbosacral, thoracic or cervical predominant)
* Neuralgic amyotrophy
* Non-systemic skin/nerve vasculitis (for example, cutaneous PAN)

#### 'Classical' distal-predominant NSVN

There is an ongoing debate over this categorisation, particularly its overlap with the condition non-diabetic radiculoplexus neuropathy. This neuropathy involves a clinical picture where the nerve damage is distally predominant as demonstrated in a nerve biopsy.

#### Warternberg migratory sensory neuropathy

Warternberg migratory sensory neuropathy is typically a multi-focal neuropathy where there is pure sensory deficits. It is characterised by sudden-onset and chronicity as well as having a propensity for relapse. It generally resolves slowly with time.

#### Postsurgical inflammatory neuropathy

Postsurgical inflammatory neuropathy is typically a multi-focal neuropathy which manifests thirty days after a surgical procedure. It mostly presents with motor and sensory symptoms. It is generally a self-limiting condition that has resolved with and without treatment.

## Diagnosis

Diagnosis of a vasculitic neuropathy depends on whether the patient first presents with multiple symptoms pointing at a systemic disorder or else primary neuropathic complaints. In the former case the patient is more likely to be assessed first by a rheumatologist and in the latter a neurologist or neurosurgeon.

## Treatments

Treatment of vasculitic neuropathy depends on the type.