Chronic cryptogenic sensory polyneuropathy: clinical and laboratory characteristics.

BACKGROUND: Chronic sensory-predominant polyneuropathy (PN) is a common clinical problem confronting neurologists. Even with modern diagnostic approaches, many of these PNs remain unclassified. OBJECTIVE: To better define the clinical and laboratory characteristics of a large group of patients with cryptogenic sensory polyneuropathy (CSPN) evaluated in 2 university-based neuromuscular clinics. DESIGN: Medical record review of patients evaluated for PN during a 2-year period. We defined CSPN on the basis of pain, numbness, and tingling in the distal extremities without symptoms of weakness. Sensory symptoms and signs had to evolve for at least 3 months in a roughly symmetrical pattern. Identifiable causes of PN were excluded by history, physical examination findings, and results of laboratory studies. We analyzed clinical and laboratory data from patients with CSPN and compared findings in patients with and without pain. RESULTS: Of 402 patients with PN, 93 (23.1%) had CSPN and stable to slowly progressive PN syndrome. These patients presented with a mean age of 63.2 years and a mean duration of symptoms of 62.9 months. Symptoms almost always started in the feet and included distal numbness or tingling in 86% of patients and pain in 72% of patients. Despite the absence of motor symptoms at presentation, results of motor nerve conduction studies were abnormal in 60% of patients, and electromyographic evidence of denervation was observed in 70% of patients. Results of laboratory studies were consistent with axonal degeneration. Patients with and without pain were similar regarding physical findings and laboratory test abnormalities. Only a few patients (<5%) had no evidence of large-fiber dysfunction on physical examination or electrophysiologic studies. All 66 patients who had follow-up examinations (mean, 12.5 months) remained ambulatory. CONCLUSIONS: Cryptogenic sensory polyneuropathy is a common, slowly progressive neuropathy that begins in late adulthood and causes limited motor impairment. Isolated small-fiber involvement is uncommon in this group of patients. Management should focus on rational pharmacotherapy of neuropathic pain combined with reassurance of CSPN's benign clinical course.

Myasthenia gravis activities of daily living profile.

The authors have developed an MG activities of daily living (ADL) profile (MG-ADL)-a simple eight-question survey of MG symptoms. In 254 consecutive encounters with established MG patients, the authors compared scores from the MG-ADL to the quantitative MG score (QMG)-a standardized, reliable scale used in clinical trials. The mean MG-ADL score was 4.89+/-3.63. The mean QMG score was 10.80+/-5.70. Pearson's correlation coefficient was 0.583 (p < 0.001). The MG-ADL is an easy-to-administer survey of MG that correlates well with the QMG and can serve as a secondary efficacy measurement in clinical trials.

Brachial amyotrophic diplegia: a slowly progressive motor neuron disorder.

OBJECTIVE: To describe a sporadic motor neuron disorder that remains largely restricted to the upper limbs over time. BACKGROUND: Progressive amyotrophy that is isolated to the upper limbs in an adult often suggests ALS. The fact that weakness can remain largely confined to the arms for long periods of time in individuals presenting with this phenotype has not been emphasized. METHODS: We reviewed the records of patients who had a neurogenic "man-in-the-barrel" phenotype documented by examination at least 18 months after onset. These patients had severe bilateral upper-extremity neurogenic atrophy that spared lower-extremity, respiratory, and bulbar musculature. RESULTS: Nine of 10 patients meeting these criteria had a purely lower motor neuron disorder. During follow-up periods ranging from 3 to 11 years from onset, only three patients developed lower-extremity weakness, and none developed respiratory or bulbar dysfunction or lost the ability to ambulate. CONCLUSION: Patients presenting with severe weakness that is fully isolated to the upper limbs, without pyramidal signs, may have a relatively stable variant of motor neuron disease.

Distal myasthenia gravis.

Myasthenia gravis (MG) characteristically involves ocular, bulbar, and proximal extremity muscles. Distal extremity muscles are typically spared or less prominently involved. The authors performed a retrospective chart review of MG patients treated at two university-based neuromuscular clinics. From a total population of 236, nine patients (3%) had distal extremity weakness exceeding proximal weakness by at least one Medical Research Council grade during their illness. Hand muscles, particularly finger extensors, were involved more frequently than were distal leg and foot muscles.

Axonal multifocal motor neuropathy without conduction block or other features of demyelination.

BACKGROUND: Conduction block is considered an essential finding for the distinction between motor neuropathies and lower motor neuron disorders. Only a small number of reports describe patients with multifocal motor neuropathies who lack overt conduction block, although in these cases other features of demyelination still suggest the presence of a demyelinating disorder. In contrast, a purely axonal multifocal motor neuropathy has not been described. METHODS: This report describes nine patients with slowly or nonprogressive multifocal motor neuropathies who had purely axonal electrodiagnostic features. RESULTS: GM1 antibodies titers were normal in all nine cases. Six patients were treated with either prednisone or IV immunoglobulin and three showed convincing improvement. CONCLUSIONS: These findings suggest an immune-mediated motor neuropathy with axonal electrophysiologic features that appears to be distinct from both multifocal motor neuropathy and established motor neuron disorders.

Denture cream: an unusual source of excess zinc, leading to hypocupremia and neurologic disease.

BACKGROUND: Chronic, excess zinc intake can result in copper deficiency and profound neurologic disease. However, when hyperzincemia is identified, the source often remains elusive. We identified four patients, one previously reported, with various neurologic abnormalities in the setting of hypocupremia and hyperzincemia. Each of these patients wore dentures and used very large amounts of denture cream chronically. OBJECTIVE: To determine zinc concentration in the denture creams used by the patients as a possible source of excess zinc ingestion. METHODS: Detailed clinical and laboratory data for each patient were compiled. Tubes of denture adhesives were analyzed for zinc content using dynamic reaction cell-inductively coupled plasma-mass spectrometry. Patients received copper supplementation. Copper and zinc levels were obtained post-treatment at varying intervals. RESULTS: Zinc concentrations ranging from about 17,000 to 34,000 mug/g were identified in Fixodent and Poli-Grip denture creams. Serum zinc levels improved in three patients following cessation of denture cream use. Copper supplementation resulted in mild neurologic improvement in two patients who stopped using denture cream. No alternative source of excess zinc ingestion or explanation for hypocupremia was identified. CONCLUSION: Denture cream contains zinc, and chronic excessive use may result in hypocupremia and serious neurologic disease.

Leprous neuropathy: an American perspective.

Although its overall prevalence is decreasing, leprosy continues to be a major cause of neuropathy worldwide. In the United States, it is a relatively rare condition. As a result, physicians may lack familiarity with the disease, which can delay diagnosis and treatment. Leprous neuropathy is characterized by involvement of dermal nerves and superficial peripheral nerve trunks in cooler body regions. A continuing pattern of immigration from endemic areas may allow practicing neurologists in any region of the country to become involved in the care of patients with leprosy. The diagnosis should be considered in patients from endemic regions presenting with peripheral neuropathy with or without skin lesions. Readily available diagnostic testing, access to subspecialists, and modern transportation and information systems through the satellite clinics of the Hansen's Disease center serve as major advantages for the management of leprosy patients in the United States.

Recurrent critical illness myopathy in an asthmatic patient treated with corticosteroids.

We report a case of recurrent critical illness myopathy in an asthmatic patient who was treated for respiratory failure with high doses of intravenous corticosteroids alone without exposure to nondepolarizing neuronmscular-bloclong agents. Each episode was followed by substantial symptomatic improvement. Our experience indicates that intravenous corticosteroids should be used with special caution in patients with a history of critical illness myopathy.

Post-radiation lower motor neuron syndrome.

UNLABELLED: Objective To describe the clinical features of four patients we encountered with post-radiation lower motor neuron syndromes and to review the related literature BACKGROUND.: Radiation therapy for malignant neoplasms has been associated with a post-radiation lower motor neuron syndrome (PRLMNS). The earliest descriptions date back to World War II. METHODS: We evaluated four patients who developed a lower motor neuron syndrome several years after the completion of radiation therapy to treat malignancies. The clinical and electrophysiological features of these patients are described. RESULTS: Our patients with PRLMNS developed weakness, muscle atrophy, loss of reflexes, and fasciculations in myotomal distributions that corresponded to the regions that had been exposed to radiation The mean time between radiation exposure and onset of motor symptoms was 14 years. Sensory symptoms were either absent or minor. Motor and sensory nerve conduction studies were normal or only mildly affected, Needle electromyography showed varying degrees of active and chronic denervation changes, primarily in the distributions that had received radiation. Magnetic resonance imaging of the spine and myelography were unremarkable. Serum creatine kinase levels were elevated in two patients. The patients followed a stable to slowly progressive course at a mean follow up of 6.5 years. CONCLUSIONS: . Patients presenting with lower motor neuron syndromes should be questioned about prior radiation exposure. A diagnosis of PRLMNS carries a relatively favorable prognosis when compared with amyotrophic lateral sclerosis, another acquired motor neuron disorder.

Cervicobrachial involvement in diabetic radiculoplexopathy.

Diabetic radiculoplexopathy is commonly viewed as a condition affecting the lower extremities. However, other regions may also be affected and the presence of upper extremity involvement has rarely been emphasized. Our goal was to illustrate the clinical features of arm involvement in this condition. Of 60 patients with diabetic lumbosacral radiculoplexopathy, we identified 9 who also had upper extremity involvement. The study included 8 men and 1 woman, ranging in age from 36 to 71 years. Upper limb involvement developed simultaneously with the onset of lower limb disorder in 1 patient, preceded it by 2 months in another patient, and occurred between 3 weeks and 15 months later in the remaining 7. In 5 cases, arm involvement developed after symptoms in the legs began to improve. The upper extremity weakness affected the hands and forearms most severely. It was unilateral in 5 patients and bilateral but asymmetric in 4. Pain was often present, but it was not a prominent feature. In most patients, neurologic deficits in the arms improved spontaneously after 2-9 months. We conclude that diabetic radiculoplexopathy may involve the cervical region before, after, or simultaneously with the lumbosacral syndrome. The upper limb process is similar to that in the legs, with subacutely progressive weakness and pain followed by spontaneous recovery.

Multifocal acquired demyelinating sensory and motor neuropathy: the Lewis-Sumner syndrome.

We report 11 patients with multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy, defined clinically by a multifocal pattern of motor and sensory loss, with nerve conduction studies showing conduction block and other features of demyelination. The clinical, laboratory, and histological features of these patients were contrasted with those of 16 patients with multifocal motor neuropathy (MMN). Eighty-two percent of MADSAM neuropathy patients had elevated protein concentrations in the cerebrospinal fluid, compared with 9% of the MMN patients (P < 0.001). No MADSAM neuropathy patient had elevated anti-GM1 antibody titers, compared with 56% of MMN patients (P < 0.01). In contrast to the subtle abnormalities described for MMN, MADSAM neuropathy patients had prominent demyelination on sensory nerve biopsies. Response to intravenous immunoglobulin treatment was similar in both groups (P = 1.0). Multifocal motor neuropathy patients typically do not respond to prednisone, but 3 of 6 MADSAM neuropathy patients improved with prednisone. MADSAM neuropathy more closely resembles chronic inflammatory demyelinating polyneuropathy and probably represents an asymmetrical variant. Given their different clinical patterns and responses to treatment, it is important to distinguish between MADSAM neuropathy and MMN.