Non-length dependent small fibre neuropathy/ganglionopathy.

OBJECTIVE: To describe the clinical and laboratory features of a painful non-length dependent, small fibre ganglionopathy (SFG). BACKGROUND: The syndrome of generalised SFG with early involvement of the face, trunk or proximal limbs is not well recognised and contrasts with the burning feet syndrome of small fibre neuropathy (SFN) and classical large fibre features of sensory ganglionopathy. METHODS: Retrospective case review including skin biopsies from four neuromuscular centres. Patients with pre-existing diseases associated with ganglionopathies were excluded. RESULTS: 12 men and 11 women, with an average age of 50 years, were studied. Neuropathic pain developed over days in eight and over months in the other patients. The face (n = 12), scalp (n = 10), tongue (n = 6), trunk (n = 15) and acral extremities (n = 21) were involved. Symptoms began in the hands or face before the legs in 10. The pain was characterised as burning (n = 22), prickling (n = 13), shooting (n = 13) or allodynic (n = 11). There was loss of pinprick sensation in affected regions in 19, with minimal or no loss of large fibre sensibility. Laboratory findings included abnormal glucose metabolism in six patients, Sjögren syndrome in three and monoclonal gammopathy, sprue and hepatitis C infection in one each, with the remainder idiopathic. Sensory nerve action potentials were normal in 12 and were reduced in the hands but normal in the legs in six. Skin biopsy in 14 of 17 showed reduced nerve fibre density in the thigh equal to or more prominent than in the calf. Two of seven patients improved with immune therapies, 13 symptomatically with analgesic medications and the remainder had little improvement. Ten considered the pain disabling at the last follow-up (mean 2 years). CONCLUSION: The pattern of symmetric, non-length dependent neuropathic pain with face and trunk involvement suggests a selective disorder of the dorsal ganglia cells subserving small nerve fibres. It can be distinguished from distal SFN. A potential metabolic or immune process was detected in half of the cases and the disorder was often refractory to treatment.

Additional causes for distal sensory polyneuropathy in diabetic patients.

OBJECTIVE: To assess the frequency of additional causes of distal sensory polyneuropathy (DSP) in patients with diabetes mellitus (DM). METHODS: Retrospective review of patients with DM and DSP during a 5 year period. A quantitative sensory score (QSS) was determined at the initial evaluation and extensive laboratory and EMG studies were performed. Patients with one or more potential causes for DSP were compared to those with DM alone. RESULTS: Fifty five patients (53%) had potential additional causes for DSP. These included: neurotoxic medications (seven), alcohol abuse (six), and B12 deficiency and renal disease (four each). The most common laboratory abnormalities were: abnormally low levels of vitamin B6 (11) or B1 (10), monoclonal gammopathy (eight), and hypertriglyceridaemia (eight). Twenty six (25%) subjects had more than one additional cause. Nine (9%) had three or more demyelinating features on EMG. There was a trend toward a lower QSS score (p = 0.05) and reduced mean amplitude of the sensory potentials in those with additional causes. Those with additional causes more often had upper limb sensory symptoms (p = 0.001) and sensory findings (p = 0.003). CONCLUSION: There was a high frequency of additional sources of DSP in patients with DM. These patients more often had sensory symptoms and findings in the hands. Tests that may be useful in the evaluation of DSP in diabetic patients include measures of vitamins B1, B6, B12, serum triglycerides, and immunofixation.

Serum potassium level and dietary potassium intake as risk factors for stroke.

BACKGROUND: Numerous studies have found that low potassium intake and low serum potassium are associated with increased stroke mortality, but data regarding stroke incidence have been limited. Serum potassium levels, dietary potassium intake, and diuretic use in relation to risk for stroke in a prospectively studied cohort were investigated. METHODS: The study comprised 5,600 men and women older than 65 years who were free of stroke at enrollment. Baseline data included serum potassium level, dietary potassium intake, and diuretic use. Participants were followed for 4 to 8 years, and the incidence and types of strokes were recorded. Low serum potassium was defined as less than 4.1 mEq/L, and low potassium intake as less than 2.4 g/d. RESULTS: Among diuretic users, there was an increased risk for stroke associated with lower serum potassium (relative risk [RR]: 2.5, p < 0.0001). Among individuals not taking diuretics, there was an increased risk for stroke associated with low dietary potassium intake (RR: 1.5, p < 0.005). The small number of diuretic users with lower serum potassium and atrial fibrillation had a 10-fold greater risk for stroke compared with those with higher serum potassium and normal sinus rhythm. CONCLUSIONS: A lower serum potassium level in diuretic users, and low potassium intake in those not taking diuretics were associated with increased stroke incidence among older individuals. Lower serum potassium was associated with a particularly high risk for stroke in the small number of diuretic users with atrial fibrillation. Further study is required to determine if modification of these factors would prevent strokes.

Rapid infusion of intravenous immune globulin in patients with neuromuscular disorders.

The safety and efficiency of a novel method of rapid-infusion IV immunoglobulin (IVIg) were retrospectively reviewed in 50 patients with neuromuscular disorders. There were 89 adverse events after 341 rapid infusions (26%), 3.5% of which were considered to be major (requiring hospitalization) and 66% minor. All patients recovered without sequelae, and there were no deaths. Fourteen of 17 patients (82%) receiving maintenance therapy preferred rapid IVIg infusion because of its convenience. Rapid-infusion IVIg can be given safely and conveniently in many patients with neuromuscular disorders.

Chronic ischemic monomelic neuropathy from critical limb ischemia.

OBJECTIVE: To describe the peripheral neuropathy resulting from chronic and critical arterial leg ischemia. METHODS: The authors evaluated 19 patients on entry to a gene therapy treatment trial for chronic and critical leg ischemia. Measurements included medical history, examination, neurologic symptom (NSS) and neurologic examination (NES) scores, motor and sensory nerve conduction studies, and quantitative sensory testing. The critically ischemic leg was compared with the less affected contralateral limb. RESULTS: All patients experienced pain from skin ulceration or vascular claudication, but many also had rest pain (58%), numbness (58%), burning (42%), and paresthesias (37%) in the ischemic foot that were consistent with peripheral nerve ischemia. Only three patients (16%) were free of neuropathic symptoms. The most common asymmetric neurologic signs included hypalgesia (74%), toe weakness (64%), hyperesthesia (63%), and pallanesthesia (53%) in the distal leg. NSS and NES were more abnormal in the critically ischemic leg, as were distal motor, total motor, and sensory examination subscores (p < 0.01 for each). Sural sensory potentials were reduced or absent, frequently on both sides. The symptomatic limb had reduced tibial motor amplitudes and increased thermal (cold) sensory thresholds (p < 0.01 for both) whereas the distal latencies, conduction velocities, and vibration thresholds were similar in the two legs. CONCLUSIONS: There is a predominantly sensory neuropathy associated with chronic and critical limb ischemia. Neuropathic symptoms are often obscured by the effects of ischemia on other tissues. The neurophysiologic changes suggest that the underlying pathophysiology is a distal axonopathy affecting nerve fibers of all sizes. Measures of blood flow in the leg correlate with neurologic symptom scores, examination scores, and electrophysiologic testing.

Nonpoliovirus poliomyelitis simulating Guillain-Barré syndrome.

BACKGROUND: Paralytic poliomyelitis due to the wild-type poliovirus has been eradicated in the United States because of effective immunization programs. In the postvaccination era, most cases are caused by other RNA viruses, such as coxsackievirus or echovirus. The condition usually begins with a fever and upper respiratory tract or gastrointestinal tract symptoms that progress to a "paralytic" phase characterized by limb weakness, areflexia, and, occasionally, respiratory failure that superficially resemble Guillain-Barré syndrome. OBJECTIVE: To describe 2 patients with nonpoliovirus poliomyelitis and highlight the findings on magnetic resonance imaging of the spinal cord to distinguish these cases from variants of Guillain-Barré syndrome. DESIGN AND SETTING: Case series from an academic medical center. PATIENTS: Following a viral illness, the patients, aged 35 and 50 years, had painless, progressive, asymmetrical weakness in the arms followed by respiratory failure in one patient, and generalized limb weakness in the other patient, reaching a nadir in 1 week. Both patients had fevers but no signs of meningitis at onset. Tendon reflexes were absent or reduced in affected regions. The cerebrospinal fluid findings were as follows: mononuclear leukocyte counts of 100 000 cells/mm(3) and 700 000 cells/mm(3), respectively, and the protein level was above 10 g/dL in both patients. Compound muscle action potential amplitudes were reduced in some nerves with active denervation in clinically affected muscles, and F-responses were absent but there were no other demyelinating features. Magnetic resonance imaging showed discrete T2-weighted signal changes of the ventral horns of the spinal cord, and one had elevated coxsackievirus titers in the serum. There was little recovery and significant atrophy in weak muscles after 3 years. CONCLUSIONS: The poliomyelitis syndrome still occurs in adults in developed countries. It has superficial similarities to a motor axonal variant of Guillain-Barré syndrome but can be distinguished by clinical, cerebrospinal fluid, and, perhaps specifically, magnetic resonance imaging characteristics.

Mild Guillain-Barré syndrome.

BACKGROUND: The unpredictability of the early course of Guillain-Barré syndrome (GBS) makes it difficult to determine which patients' conditions will worsen under observation. Most large randomized treatment trials for GBS have used an inability to walk as the enrollment criterion. Consequently, little is known about the treatment of those patients with milder degrees of affection. OBJECTIVES: To determine the approximate frequency of mild GBS with the persistent ability to walk and to see if there were features that predicted that the illness would remain mild. SETTING: A registry of patients with GBS seen on the wards and in the neurology clinic from January 1,1992, to May 1, 2000, in a 400-bed community teaching hospital. PATIENTS: Twelve (4.7%) of 254 patients in our case series were able to walk throughout their illness. Eight had been treated with plasmapheresis or intravenous immunoglobulin; the others were observed without treatment. RESULTS: There was no age, sex, or seasonal preponderance in comparison with large case series that included cases of all severities. Nine of 12 patients had a preceding respiratory tract infection, 10 had paresthesias, 7 had prominent pain, and 9 had ataxia. Seven of 10 patients who were examined had normal cerebrospinal fluid protein levels. It took 8 days, on average, to reach the maximal degree of weakness. One additional treated patient, excluded from our case series, had mild weakness for the first 3 weeks and subsequently worsened with a relapsing course more typical of chronic inflammatory demyelinating polyneuropathy. Eleven patients demonstrated proximal, intermediate, or distal conduction block, and only 3 had a mild degree of denervation. There were no distinguishing clinical or electrophysiologic features between treated and untreated patients with mild GBS and, except for the mild degree of affection and the absence of substantial electromyographic changes of axonal disruption, there were no important differences between these mild cases as a group and patients who developed more severe GBS. CONCLUSIONS: Cases of mild GBS reach a clinical nadir in a similar time to those with more severe disease. Treatment may be unnecessary in patients who are able to walk during the second week of illness, but observation until approximately the eighth day seems appropriate to be certain that the illness does not progress. In all likelihood there are mild cases of GBS that never come to the attention of a neurologist.

Improvement in chronic ischemic neuropathy after intramuscular phVEGF165 gene transfer in patients with critical limb ischemia.

OBJECTIVE: To investigate the effects of vascular endothelial growth factor gene therapy on ischemic neuropathy in patients with critical limb ischemia. DESIGN: An open-label, dose-escalating trial. Patients with angiographically proven critical leg ischemia received injections of phVEGF(165) human plasmid in the muscles of the ischemic limb. Testing before treatment and at 3 and 6 months included (1) symptom severity score, (2) clinical examination score, and (3) electrophysiologic studies. Clinical and electrophysiologic examiners were masked to each other's findings. SETTING: A tertiary care referral hospital and a major teaching affiliate of Tufts University School of Medicine, Boston, Mass. RESULTS: Of 29 consecutive patients enrolled, 17 (19 limbs) completed the 6 months of study. Six patients had diabetes. Compared with baseline studies, treated patients had significant clinical improvements in the symptom score (P<.01), sensory examination score (P<.01), total examination score (P =.01), peroneal motor amplitude (P =.03), and quantitative vibration threshold (P =.04). Improvement in the vascular ankle-brachial index in treated legs (P<.01) corresponded to improvement in neuropathy in the same limb. Neurologic improvement was seen in 4 of 6 patients with diabetes who completed the study. No clinical, electrophysiologic, or vascular improvements were observed in untreated legs. CONCLUSIONS: Ischemic neuropathy might be a reversible condition, and therapeutic angiogenesis might be an effective treatment. The presence of diabetes does not preclude a response to this therapy.

Reversal of experimental diabetic neuropathy by VEGF gene transfer.

The pathogenetic basis for diabetic neuropathy has been enigmatic. Using two different animal models of diabetes, we have investigated the hypothesis that experimental diabetic neuropathy results from destruction of the vasa nervorum and can be reversed by administration of an angiogenic growth factor. Nerve blood flow, as measured by laser Doppler imaging or direct detection of a locally administered fluorescent lectin analogue, was markedly attenuated in rats with streptozotocin-induced diabetes, consistent with a profound reduction in the number of vessels observed. A severe peripheral neuropathy developed in parallel, characterized by significant slowing of motor and sensory nerve conduction velocities, compared with nondiabetic control animals. In contrast, 4 weeks after intramuscular gene transfer of plasmid DNA encoding VEGF-1 or VEGF-2, vascularity and blood flow in the nerves of treated animals were similar to those of nondiabetic control rats; constitutive overexpression of both transgenes resulted in restoration of large and small fiber peripheral nerve function. Similar experiments performed in a rabbit model of alloxan-induced diabetes produced comparable results. These findings support the notion that diabetic neuropathy results from microvascular ischemia involving the vasa nervorum and suggest the feasibility of a novel treatment strategy for patients in whom peripheral neuropathy constitutes a secondary complication of diabetes.

Treatment experience in patients with anti-myelin-associated glycoprotein neuropathy.

We report our experience with 24 consecutively treated patients (15 men and 9 women, median age 64 years) with anti-myelin-associated glycoprotein (anti-MAG) neuropathy. The rates of response to plasma exchange (40%), immune globulin (16%), and cyclophosphamide-based therapy (36%) were similar. Five (24%) responded to the first treatment modality, 32% to a second, alternative modality, and 31% to a third. Only 4 of 12 responders had sustained improvement; the others relapsed after a median of 7 months. In those 4 patients, the median immunoglobulin M (IgM) level dropped by 25% compared to an increase of 24% in the nonresponders (P = 0.04). Thus, most patients with anti-MAG neuropathy failed to have sustained improvement after treatment, and none of the therapies emerged as superior. Disability improved transiently after therapy in approximately 50% of cases. A 25% reduction of the IgM level predicted sustained improvement, but was difficult to achieve. There were no clinical or electrodiagnostic features associated with a treatment response, nor did a reduction of the anti-MAG antibody titer correlate with clinical improvement.

Flaccid quadriplegia from tonsillar herniation in pneumococcal meningitis.

A young woman with fulminant pyogenic meningitis became quadriplegic, areflexic and flaccid due to herniation of the cerebellar tonsils and compression of the upper cervical cord. This state of spinal shock was associated with absent F-waves. Intracranial pressure was greatly elevated and there was an uncertain relationship of tonsillar descent to a preceding lumbar puncture. Partial recovery occurred over 2 years. Tonsillar herniation can cause flaccid quadriplegia that may be mistaken for critical illness polyneuropathy. This case demonstrates cervicomedullary infarction from compression, a mechanism that is more likely than the sometimes proposed infectious vasculitis of the upper cord.

A case of Balamuthia mandrillaris meningoencephalitis.

Balamuthia mandrillaris is a newly described pathogen that causes granulomatous amebic encephalitis, an extremely rare clinical entity that usually occurs in immunosuppressed individuals. We report a case of pathologically proven Balamuthia encephalitis with unusual laboratory and radiologic findings. A 52-year-old woman with idiopathic seizures and a 2-year history of chronic neutropenia of unknown cause had a subacute illness with progressive lethargy, headaches, and coma and died 3 months after the onset of symptoms. Cerebrospinal fluid (CSF) glucose concentrations were extremely low or unmeasurable, a feature not previously described (to our knowledge). Cranial magnetic resonance imaging scans showed a single large temporal lobe nodule, followed 6 weeks later by the appearance of 18 ring-enhancing lesions in the cerebral hemispheres that disappeared after treatment with antibiotics and high-dose corticosteroids. The initial brain biopsy specimen and analysis of CSF samples did not demonstate amebae, but a second biopsy specimen and the postmortem pathologic examination showed Balamuthia trophozoites surrounded by widespread granulomatous inflammation and vasculitis. The patient's neutropenia and antibiotic use may have caused susceptibility to this organism. Amebic meningoencephalitis should be considered in cases of subacute meningoencephalitis with greatly depressed CSF glucose concentrations and multiple nodular lesions on cerebral imaging. Arch Neurol. 2000;57:1210-1212

Progressive necrotic myelopathy: clinical course in 9 patients.

OBJECTIVE: To review the clinical, laboratory, and radiological findings of 9 patients who had progressive idiopathic myelopathy with evidence of spinal cord necrosis. DESIGN AND METHODS: We reviewed personally examined cases of myelopathy that fulfilled the following criteria: (1) regional loss of reflexes, flaccidity, and muscle atrophy; (2) magnetic resonance imaging showing a shrunken or cavitated cord without evidence of arteriovenous malformation; (3) electromyogram showing denervation over several contiguous spinal cord sgements with preservation of sensory potentials in some cases; and (4) the absence of evidence of systemic disease or neoplasm. RESULTS: The illness began in these patients after the age of 40 years, with prominent burning or tingling limb pain, occasionally with radicular features or with less well-defined back, neck, or abdominal pain. Leg or infrequently arm weakness appeared concurrently or soon after the onset of pain. The most distinctive feature was a saltatory progression of symptoms, punctuated by both acute and subacute worsenings approximately every 3 to 9 months, culminating in paraplegia or tetraplegia. The distinguishing clinical findings, together indicative of destruction of gray matter elements of the cord, were limb atrophy, persistent areflexia, and flaccidity. The concentration of cerebrospinal fluid protein was typically elevated between 500 g/L and 1000 g/L, without oligoclonal bands, accompanied infrequently by pleocytosis. Magnetic resonance imaging showed features suggesting cord necrosis, specifically swelling, T2-weighted hyperintensity, and gadolinium enhancement over several spinal cord segments, succeeded months later by atrophy in the same regions. Necrosis of the cord was found in biopsy material from one patient and postmortem pathology in another case, but inflammation and blood vessel abnormalities were absent. Only 2 patients had prolonged visual evoked responses. The disease progressed despite immune-modulating treatments although several patients had brief epochs of limited improvement. CONCLUSIONS: The saltatory course, prolonged visual evoked responses in 2 patients, and a cranial abnormality on magnetic resonance imaging in another, raised the possibility of a link to multiple sclerosis. However, the normal cranial magnetic resonance imaging scans in 6 other patients, uniformly absent oligoclonal bands, and poor response to treatment were atypical for multiple sclerosis. On the basis of shared clinical and laboratory features, idiopathic progressive necrotic myelopathy is indistinguishable from a limited form of Devic disease.

Favorable effect of VEGF gene transfer on ischemic peripheral neuropathy.

Ischemic peripheral neuropathy is a frequent, irreversible complication of lower extremity vascular insufficiency. We investigated whether ischemic peripheral neuropathy could be prevented and/or reversed by gene transfer of an endothelial cell mitogen designed to promote therapeutic angiogenesis. Intramuscular gene transfer of naked DNA encoding vascular endothelial growth factor (VEGF) simultaneously with induction of hindlimb ischemia in rabbits abrogated the substantial decrease in motor and sensory nerve parameters, and nerve function recovered promptly. When gene transfer was administered 10 days after induction of ischemia, nerve function was restored earlier and/or recovered faster than in untreated rabbits. These findings are due in part to enhanced hindlimb perfusion. In addition, however, the demonstration of functional VEGF receptor expression by Schwann cells indicates a direct effect of VEGF on neural integrity as well. These findings thus constitute a new paradigm for the treatment of ischemic peripheral neuropathy.

Influence of diabetes mellitus on chronic inflammatory demyelinating polyneuropathy.

Patients with diabetes occasionally develop clinical and electrodiagnostic features suggestive of chronic inflammatory demyelinating polyneuropathy (CIDP). To clarify the role of diabetes in patients with a CIDP-like syndrome, we compared the clinical, pathological, and electrodiagnostic features of 14 patients (10 men, 4 women) with diabetes and CIDP (DM-CIDP) to 60 patients with idiopathic CIDP (I-CIDP). The average duration of diabetes was 9 years. The patients with DM-CIDP were older and more often complained of imbalance compared to the idiopathic group, but the frequency of other symptoms and neurologic findings were similar. The mean amplitude of the ulnar compound muscle action potential in the DM-CIDP group was comparatively reduced, the sural sensory nerve action potential was more often absent, and axonal loss was more commonly observed on nerve biopsy. The response rate to treatment was similar, but the magnitude of functional recovery was greater in patients with I-CIDP. Thus, our patients with diabetes and CIDP had clinical features similar to those with idiopathic CIDP, but their nerve conduction studies and nerve biopsies showed more severe axonal loss and the degree of improvement following treatment was less favorable. These differences most likely reflect the additive effects of superimposed diabetic axonal polyneuropathy in patients who develop CIDP.

Upper limb predominant, multifocal chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy (CIDP) presents in rare instances with focal or multifocal upper limb involvement. We reviewed the clinical and electromyographic (EMG) characteristics of 10 such patients (UL-CIDP) and compared them with patients with typical generalized CIDP (G-CIDP) and multifocal motor neuropathy (MMN). There were six men and four women, with a mean age of 54 years. Symptoms began in one arm or hand in six patients and in both arms or hands in four and included numbness (n = 10), paresthesias (n = 9), weakness (n = 8), and pain (n = 6). Findings were initially restricted to the ulnar nerve distribution in three patients, and median and axillary nerve in one patient each, and involved multiple nerves in five. Conduction block was detected in the forearm segment of 68% of the median and ulnar motor nerves tested; in contrast to multifocal motor neuropathy, 73% of the sensory nerves tested were abnormal, and none had anti-GM1 antibodies. Aside from a regional onset, there were no clinical or electrophysiological features that distinguished patients with UL-CIDP from those with G-CIDP. However, the magnitude of recovery following treatment was greater in patients with G-CIDP. We conclude that a multifocal variant of CIDP begins with upper extremity sensorimotor symptoms, simulates isolated or multiple mononeuropathies, can be distinguished from MMN, and may have a less favorable response to treatment.

Chronic motor axonal neuropathy: pathological evidence of inflammatory polyradiculoneuropathy.

Chronic immune and inflammatory motor neuropathies may resemble motor neuron disease, and the distinction may be particularly difficult if conduction block or GM1 antibodies are absent. The pathology of this axonal type of chronic motor neuropathy has not been characterized except in a few cases associated with paraproteinemia. We describe the clinical, electrophysiological, and pathological findings in a patient with a chronic motor axonal neuropathy, normal immunoelectrophoresis, and no GM1 antibodies. At autopsy the spinal cord was normal with the exception of chromatolytic motor neurons. All the ventral roots were greatly thinned. Of 10 mixed nerves and numerous spinal roots sampled, five showed areas of perineurial, perivascular lymphocytic infiltration. There was severe axonal loss in the motor roots that was not as evident in mixed nerves, and the sensory nerves and roots were virtually unaffected. Our findings suggest that a chronic motor axonal neuropathy without paraproteinemia or GM1 antibodies may, in some cases, result from an inflammatory process.