Ischemic monomelic neuropathy.

Ischemic monomelic neuropathy is an uncommon complication associated with the creation of arteriovenous (AV) fistula for hemodialysis. After placement of an arteriovenous fistula, there can be shunting of arterial blood away from the distal extremity resulting in damage to distal nerve fibers with acute neurologic symptoms. It can present with global muscle pain, weakness, and a warm hand with palpable pulses starting within the 1 st h after the creation of the AV fistula. It is a devastating complication and can result in permanent disability. We hereby report two cases of ischemic monomelic neuropathy associated with the creation of a brachiocephalic AV fistula for hemodialysis access.

Introduction

Ischemic monomelic neuropathy is an uncommon complication associated with the creation of arteriovenous (AV) fistula for hemodialysis.[1] It is a distinct clinical entity involving dysfunction of multiple upper extremity peripheral nerves. Symptom onset is usually immediate, and neurologic symptoms are dominant, often in the absence of significant clinical ischemia of the hand. The etiology is considered to be an ischemic insult to the proximal limb which results in multiple axonal loss mononeuropathies.[23] It is a devastating complication of AV access which can result in permanent disability even if intervened immediately. We hereby report two cases of ischemic monomelic neuropathy associated with the creation of a brachiocephalic AV fistula for hemodialysis access.

Case Reports

Case 1

A 49-year-old male, with a history of long-standing Type 2 diabetes mellitus with neuropathy and chronic kidney disease presented to the emergency department with severe breathlessness and features of volume overload. He was initiated on hemodialysis via jugular access. However, for long-term maintenance hemodialysis, a brachiocephalic AV fistula was created on the left side [Figure 1a]. Around 1 h later, he felt severe pain and paraesthesia of the left forearm and hand and was unable to move his fingers and wrist. The left hand remained warm, and the radial pulse was well felt. On clinical examination, he was unable to flex the wrist and fingers of the left hand. He had clawing of left hand [Figure 1b]. He was also unable to extend the wrist and fingers of the left hand [Figure 1c]. He had loss of sensations involving the palm and dorsum of the left hand. Finger flexion reflex was absent in the left hand. Other deep tendon reflexes were present. Clinical features were suggestive of median, radial, and ulnar nerve palsy involving the left upper limb. A Doppler study of the left upper limb was done, and it was normal. Nerve conduction study was done, and the left median and ulnar nerves were not stimulatable, and compound muscle action potential from left radial was significantly reduced, suggestive of a severe neuropathy involving the left median, ulnar and radial nerves. In view of the acute onset of dysfunction involving multiple nerves of the upper extremity after the creation of an AV fistula, with a well palpable radial pulse, the possible diagnosis of ischemic monomelic neuropathy was considered. Two days later, he underwent closure of the brachiocephalic fistula. However, his symptoms did not show marked improvement.

Figure 1

(a) Left brachiocephalic arteriovenous fistula. (b) Clawing of the left hand. (c) Inability to extend wrist and fingers of the left hand

Case 2

A 62-year-old male with a history of long-standing Type 2 diabetes mellitus was diagnosed to have chronic kidney disease 2 months back. A brachiocephalic AV fistula was created on the left side for being initiated on hemodialysis. Soon after the procedure, he developed numbness in his left hand and was unable to move the fingers of his left hand. His left radial pulse was well palpable. On clinical examination, he was unable to flex or extend his left wrist and was unable to flex or extend the fingers of the left hand, with sensory loss over the dorsum and palmar aspect of the left hand, suggestive of radial, median, and ulnar nerve palsy on the left side. Nerve conduction study was done, and the left median, radial and ulnar nerves were not stimulatable.

Hence, the possibility of an ischemic monomelic neuropathy was considered. He did not undergo the brachiocephalic fistula closure. His neurological deficit was persisting on review at 1 month.

Discussion

Ischemic monomelic neuropathy is a potentially devastating complication of AV access for hemodialysis. It was first described by Wilbourn et al. in 1983.[4] He described it as a condition with arterial insufficiency (ischemic) involving a single extremity (monomelic) and causing selective dysfunction (neuropathy) of multiple peripheral nerves. After placement of an AV fistula, there can be shunting of arterial blood away from the distal extremity resulting in damage to distal nerve fibers with acute neurologic symptoms but insufficient ischemia to cause muscle or skin ischemia or necrosis. The true incidence of ischemic monomelic neuropathy following hemodialysis access surgery is not established.[5] Zanow et al., in his review on more than 5000 procedures, found the incidence of access-related ischemia to be 0.3% for wrist fistulas and 1.8% for elbow fistulas.[1] Risk factors include female sex, diabetes with peripheral neuropathy and atherosclerotic vascular disease. Symptoms include pain, paresthesias, and numbness in the distribution of all three forearm nerves and diffuse motor weakness or paralysis. These deficits often are less severe proximally and more severe distally. The hand is usually warm, and often a palpable radial pulse or audible Doppler signal is present. Nerve conduction studies in patients with IMN show axonal loss and reduced motor and sensory nerve conduction velocities in the radial, ulnar, and median nerves. The differential diagnosis of IMN includes vascular steal, neurologic complications of axillary block anesthesia or patient positioning, carpal tunnel syndrome or other peripheral nerve compression, and postoperative pain and functional deficit secondary to surgical trauma or venous hypertension and postoperative swelling.[6]

The kidney disease outcome quality initiative recommends that immediate closure of the AV fistula is mandatory.[78] However, even with early access closure, paralysis, and pain may be permanent or only partially reversible.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.