An investigation of the pathophysiology of ischaemic neuropathy

Ischaemic monomelic neuropathy of the lower limb

Background: Ischaemic mononeuropathy (IMN) is a rarely reported type of peripheral neuropathy secondary to an ischaemic injury, due to a complication of haemodialysis access. Although underreported, this phenomenon typically occurs in diabetic patients and may reflect the predisposition to neuropathic injury on a background of chronic deleterious changes in the microvasculature in diabetes. It is characterised by mononeuropathic features such as paraesthesia, pain and motor weakness and usually is reported as a rare complication of brachiocephalic fistula. We report a case of IMN which occurred in a patient with end-stage diabetic nephropathy following polytetrafluoroethylene (PTFE) graft placement in the groin as vascular access for haemodialysis.

Postpartum Sciatic Neuropathy After Uncomplicated Vaginal Delivery

Postpartum neuropathies are common, including femoral neuropathy, peroneal neuropathy, lumbosacral trunk plexopathy, and lateral femoral cutaneous neuropathy. Sciatic mononeuropathy in the peripartum period is rare. Postpartum sciatic neuropathy (PSN) in the setting of cesarean section has been reported before. We present a case series of 2 sciatic mononeuropathies after vaginal delivery. Case 1 is a 25-year-old woman who presented with a left foot drop after normal vaginal delivery after being in labor for 3 hours. Case 2 is a 24-year-old woman who presented with a right foot drop after normal vaginal delivery and being in labor for 31 hours. Both cases noted foot drops in the immediate postpartum period. Neurologic examinations revealed flail foot, 4/5 hamstring muscle strength on MRC scale and intact hip abduction. They had paresthesia on the posterolateral aspect of the leg, dorsal and plantar aspect of the foot with absent ankle reflex. MRI did not show evidence of spinal cord, nerve root or plexus involvement. Electrodiagnostic studies revealed evidence of sciatic mononeuropathy proximal to the short head of biceps femoris. They were discharged home with an ankle brace and therapy. At 3 months follow up, they had complete resolution of weakness. There have been a few reported cases of PSN secondary to cesarean section. Sciatic involvement after vaginal delivery is extremely rare. We report 2 cases of PSN after vaginal delivery to highlight that sciatic mononeuropathy can occur not only after cesarean section, but also after uncomplicated vaginal delivery and should raise awareness of this risk to clinicians.

Spontaneous ischemic neuropathy of the sciatic nerve due to arterial occlusion – a rare cause of acute neuropathy not to be missed, a report of two cases

Background

Ischemic neuropathy of the sciatic nerve without preceding vascular surgical procedures is a rare condition and may be due to arterial occlusion in one limb.

Case presentations

We present two cases with acute onset of pain and sensory symptoms such as pins and needles and numbness in the foot with no or mild motor symptoms. In the neurological work-up, electrophysiological signs of axonal neuropathy of both peroneal and tibial nerves were demonstrated and T2 hyperintensity was seen in the distal sciatic nerves on MR neurography as well as signs indicating arterial thrombosis in the corresponding vessels. Recanalization was obtained in both patients angiographically with significant improvement in one patient.

Conclusions

Spontaneous arterial occlusion of major or peripheral arteries is a rare but important cause of acute onset of single or multiple axonal mononeuropathies of one extremity. Recognition of this infrequent cause is essential since it requires immediate and specific therapeutic options.

Ischemic Monomelic Neuropathy after Arteriovenous Fistula Surgery: Clinical Features, Electrodiagnostic Findings, and Treatment

Ischemic monomelic neuropathy (IMN) is a rare complication of vascular access in the hemodialysis patients, characterized by multiple mononeuropathies in the absence of clinical ischemia. Most commonly seen in the female gender, diabetes mellitus, and it must be differentiated from vascular steal syndrome, where we see clinical ischemia as the main pathognomonic feature. Early recognition of the symptoms and prompt intervention was shown to be beneficial. A delay in the treatment can lead to irreversible damage to the nerves and muscles. This article is depicting a case of an elderly male patient who presented with signs and symptoms of IMN which developed after arteriovenous (AV) fistula graft surgery.

Ischemic Monomelic Neuropathy: An Underappreciated Cause of Pain and Disability following Vascular Access Surgery

The establishment and maintenance of a functioning arteriovenous access site is essential for the care of the hemodialysis (HD) patient. Ischemic monomelic neuropathy (IMN) represents an underappreciated complication and an unrecognized source of short- and long-term disability because of its protean manifestations in the post-operative period. Delayed diagnosis of IMN greatly reduces the chance of avoiding irreversible disability. Prompt diagnosis and early management of IMN can avoid morbidity for the patient, diminish healthcare costs for the system and avoid medical liability for care providers. A multidisciplinary awareness of the symptoms of IMN is essential to permit prompt diagnosis and management.

A Case of Acute Ischemic Monomelic Neuropathy and Review of the Literature

Ischemia monomelic neuropathy is rare and underrecognized complication of hemodialysis access (HA), characterized by diffuse multiple mononeuropathies in the absence of significant clinical ischemia. It is important to diagnose this syndrome early because ligation of the HA is the most accepted treatment to prevent or at least halt irreversible neural dysfunction and therefore, chronic pain and disability. Literature describing this fistulae-related pathology is rare, and we attempt to increase its awareness.

Ischemic Monomelic Neuropathy: A Rare but Important Complication after Hemodialysis Access Placement - a Review

The creation of a vascular access for hemodialysis is a frequently performed procedure. Ischemic monomelic neuropathy (IMN) is a rare, but important complication of hemodialysis access (HA) procedures, which can lead to severe and nonreversible limb dysfunctions. Therefore, in any case of postoperative neurological malfunction, immediate neurological investigations should be undertaken. If IMN is diagnosed, improvement of distal perfusion should be established without delay. IMN is a form of hemodialysis-associated ischemic syndrome (as the so-called steal syndrome), but experiences with this complication are small. Every case of IMN should be carefully documented and if possible published, to gain more experience about this rare but important complication.

Complications of arteriovenous hemodialysis access: recognition and management

English language citations reporting complications of arteriovenous access for hemodialysis are critically reviewed and discussed. Venous hypertension, arterial steal syndrome, and high-output cardiac failure occur as a result of hemodynamic alterations potentiated by access flow. Uremic and diabetic neuropathies are common but may obfuscate recognition of potentially correctable problems such as compression or ischemic neuropathy. Mechanical complications include pseudoaneurysm, which may develop from a puncture hematoma, degeneration of the wall, or infection. Dysfunctional hemostasis, hemorrhage, noninfectious fluid collections, and access-related infections are, in part, manifestations of the adverse effects of uremia on the function of circulating hematologic elements. Impaired erythropoiesis is successfully managed with hormonal stimulation; perhaps, similar therapies can be devised to reverse platelet and leukocyte dysfunction and reduce bleeding and infectious complications.

Acute painless paraparesis due to bilateral femoral artery occlusion

Acute peripheral arterial occlusion is a medical emergency manifesting with pain, pallor, absence of pulse, paralysis, and paresthesia. Neurological deficits have occasionally been described as the presenting symptoms of acute arterial ischemia. We report a patient with acute bilateral occlusion of the femoral arteries and an underlying severe atherosclerotic aorto-iliac disease who presented with acute painless paraplegia and anesthesia in the lower extremities. The patient underwent arterial thrombectomy of the right and left femoral artery, followed by angioplasty and stent insertion of the right and left common iliac artery within 5 h from the onset of his symptoms. Subsequent physical therapy resulted in rapid improvement in the strength of his lower extremities and the patient was able to walk unaided after two weeks.

Ultrasound therapy facilitates the recovery of acute pressure-induced conduction block of the median nerve in rabbits

Though the use of ultrasound for the treatment of carpal tunnel syndrome (CTS) or compression neuropathy has been described, its effect remains controversial. A test model of acute CTS was developed using rabbits. Acute median nerve compression was induced by the infusion of saline into the carpal tunnel under general anesthesia to elevate the intracarpal pressure. A reduction in the compound muscle action potential (CMAP) amplitude of the abductor pollicis was noted after intracarpal pressure increased. To investigate the efficacy of ultrasound in acute CTS, rabbits with acute median nerve compression were divided into 3 groups (10 each) and ultrasound was applied at different intensities to each group as follows: 1.5 W/cm(2) to group 1; 0.2 W/cm(2) to group 2; 0.0 W/cm(2) (sham) to group 3. A total of 10 treatment sessions were given over a period of 2 weeks. Following ultrasound application, the CMAP amplitudes showed significant improvement in group 1 compared to the other two groups (P < 0.05), indicating facilitated recovery from acute CTS in this pressure-induced median nerve compression rabbit model. The benefits of ultrasound application in a clinical setting must be verified by further clinical trials.

Sensory axonopathy in mild to moderate peripheral arterial disease

The effect of mild to moderate arterial occlusive disease on peripheral nervous system conduction was prospectively investigated in 18 subjects and 18 control subjects, aged 40 to 85 years. Experimental and control subjects underwent a thorough history and physical followed by vascular and electrophysiologic studies. The primary outcome measure was the sensory nerve action potential. Although 33% of the subjects with peripheral arterial disease had experienced paresthesias, the clinical evaluation of sensation was relatively unaffected. Sensory conduction studies revealed 30% absent sural responses and 56% absent superficial peroneal nerve responses in subjects with peripheral arterial disease compared with 3 and 14% absent responses in control subjects, respectively (P = 0.044; 0.025). There were no differences in distal latency or sensory amplitude, although the superficial peroneal amplitude did approach significance (P = 0.06). No significant differences were found in motor distal latency, amplitude, or conduction velocity. Age, leg length, temperature, disease severity, presence of paresthesias, cholesterol levels, and past alcohol or tobacco ingestion did not account for the difference in sensory responses. These results support the presence of a mild sensory axonopathy in subjects with peripheral arterial disease. Electromyographers should be cognizant of absent distal responses from peripheral arterial disease so as not to ascribe the findings to an alternative pathology and should not attribute abnormal motor conduction results to the presence of this degree of peripheral arterial disease.

Foot drop as a harbinger of aortic occlusion

A man presented with foot drop and 2 months later an infrarenal occlusion of his abdominal aorta was discovered. Initial evaluation found no structural etiology for his nerve injury. His neurologic deficits progressed until gangrenous changes developed in his feet leading to the discovery of aortic occlusion. This case demonstrates that peripheral nerve injury in the legs may signal underlying large vessel occlusive disease. We discuss the localization and potential mechanisms of ischemic nerve injury.

Ischemic monomelic neuropathy: an under-recognized complication of hemodialysis access

During the past 3 years six episodes of ischemic monomelic neuropathy (IMN) have been identified in five patients as a complication of upper extremity dialysis grafts. All patients had long-standing insulin-dependent diabetes, peripheral neuropathy, and brachial artery graft origins, whereas 60% had peripheral vascular disease. Five episodes occurred immediately after graft placement, whereas one was due to a graft-related thromboembolus. Diagnostic delay was common with initial findings attributed to anesthesia, positioning, or surgical trauma. Electrophysiologic studies showed underlying diabetic neuropathy with severe multifocal neuropathy distal to the grafts. Digital pressure indices were reduced but there was no critical ischemia. In three cases ischemia was completely corrected with improvement in one. One patient had proximal balloon angioplasty with no improvement and of the two untreated patients, one improved slightly. Ischemic monomelic neuropathy is a rare but disabling complication of dialysis access in diabetic uremic patients. Its occurrence is unpredictable and diagnostic delay is common. Correction of ischemia is indicated but usually does not improve the neuropathy. Prevention requires further research to more accurately characterize the patients at risk.