Ischemic Monomelic Neuropathy
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Joseph Nasr, M.D.[2]
Overview
Ischemic monomelic neuropathy (IMN) is a rare but severe neurologic complication that occurs after creation of an arteriovenous access for hemodialysis, most commonly with brachial artery–based fistulas or grafts. It is characterized by acute ischemic injury to peripheral nerves of the forearm and hand, resulting in profound sensory and motor deficits despite preserved distal pulses and a warm, well-perfused extremity.
IMN is a medical and surgical emergency. Delay in recognition and treatment leads to permanent neurologic disability.
Epidemiology
Ischemic monomelic neuropathy is uncommon, with an estimated incidence of approximately 0.1% to 0.5% following hemodialysis access creation. It occurs almost exclusively in patients with end-stage kidney disease and is strongly associated with brachial artery–based arteriovenous access.[1][2]
Pathophysiology
IMN results from acute diversion of arterial blood into a newly created arteriovenous access, leading to sudden hypoperfusion of the vasa nervorum supplying the median, ulnar, and radial nerves. Unlike access-related hand ischemia, distal arterial flow to skin and muscle may remain sufficient, while neural tissue—highly sensitive to ischemia—undergoes axonal injury and infarction.
Risk factors include diabetes mellitus, peripheral vascular disease, preexisting peripheral neuropathy, and limited collateral circulation.[1][2]
Clinical features
Symptoms typically develop within minutes to hours after access creation and include:
- Severe, deep, burning pain in the forearm and hand
- Global sensory loss involving multiple nerve distributions
- Profound motor weakness or paralysis of the hand
- Loss of wrist extension and intrinsic hand muscle function
On physical examination:
- The hand is warm and well perfused
- Distal pulses are palpable
- Capillary refill is preserved
These findings distinguish IMN from classic access-related hand ischemia.
Differential diagnosis
Ischemic monomelic neuropathy must be differentiated from:
- Access-related hand ischemia (steal syndrome) Presents with coolness, pallor, diminished pulses, and tissue ischemia
- Carpal tunnel syndrome Median nerve–limited symptoms, nocturnal worsening, no acute onset
- Ulnar neuropathy Gradual onset, focal ulnar distribution, typically compressive
- Postoperative pain or residual nerve block
Failure to recognize IMN is common due to preserved distal perfusion and misleading physical findings.
Diagnosis
Diagnosis is clinical and based on:
- Acute onset of severe neurologic deficits after access creation
- Global involvement of multiple peripheral nerves
- Preserved distal pulses and hand warmth
Noninvasive hemodynamic studies are typically normal. Electrodiagnostic testing may demonstrate axonal loss but should not delay treatment.
Management
Immediate ligation of the arteriovenous access is required.
There is no effective conservative or reconstructive therapy for IMN. Delay in access ligation results in irreversible nerve injury and permanent motor and sensory deficits.[1]
Prognosis
Even with prompt intervention, neurologic recovery may be incomplete. Delayed diagnosis is associated with permanent hand dysfunction, disability, and loss of independence.
References
- ↑ 1.0 1.1 1.2 Thermann F, Kornhuber M. Ischemic monomelic neuropathy: a rare but important complication after hemodialysis access placement—a review. J Vasc Access. 2011;12(2):113-119. doi:10.5301/JVA.2011.6365
- ↑ 2.0 2.1 Wilbourn AJ, Furlan AJ, HulleyW, Ruschhaupt W. Ischemic monomelic neuropathy. Neurology. 1983;33(4):447-451. doi:10.1212/WNL.33.4.447