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Biomedical subjects

R J Barohn

Publications and source records attributed to R J Barohn.

At least 37 records · Page 2Linked to original sources
PubMed2000

Distal acquired demyelinating symmetric neuropathy.

OBJECTIVE: To characterize an acquired, symmetric, demyelinating neuropathic variant with distal sensory or sensorimotor features. BACKGROUND: Classic chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients have prominent proximal and distal weakness. However, chronic demyelinating neuropathies may present with different phenotypes. An approach that distinguishes these disorders primarily according to the pattern of weakness may be useful to the clinician. METHODS: A total of 53 patients with acquired symmetric demyelinating polyneuropathies were classified primarily according to the pattern of the neuropathy and secondarily according to the presence and type of monoclonal protein (M-protein) in this retrospective review. The authors distinguished between patients with distal sensory or sensorimotor involvement, designated as distal acquired demyelinating symmetric (DADS) neuropathy, from those with proximal and distal weakness, who were designated as CIDP. RESULTS: M-proteins were present in 22% of patients with CIDP. There were no features that distinguished clearly between CIDP patients with or without an M-protein, and nearly all of these patients responded to immunomodulating therapy. In contrast, nearly two-thirds of the patients with DADS neuropathy had immunoglobulin M (IgM) kappa monoclonal gammopathies, and this specific combination predicted a poor response to immunomodulating therapy. Antimyelin-associated glycoprotein (anti-MAG) antibodies were present in 67% of these patients. CONCLUSION: Distinguishing acquired demyelinating neuropathies by phenotype can often predict the presence of IgM kappa M-proteins, anti-MAG antibodies, and responses to immunomodulating therapy.

Adult↗
PubMed2000

McArdle's disease presenting with asymmetric, late-onset arm weakness.

McArdle's disease or myophosphorylase deficiency is one of the most common muscle glycogenoses and typically presents in childhood or adolescence with exercise intolerance, myalgia, myoglobinuria, and cramps in exercising muscle. We describe an elderly man who developed asymmetric proximal arm weakness at age 73. He had no history of exercise-induced cramps, myalgias, or myoglobinuria. Creatine kinase levels were elevated, serum lactate did not rise on ischemic exercise testing, and muscle biopsy showed a vacuolar myopathy with absent myophosphorylase activity. This unusual case demonstrates that McArdle's disease may present with fixed, asymmetric proximal weakness at an advanced age and should be considered in this clinical setting, especially when a history of poor exercise tolerance can be elicited.

Aged↗
PubMed1999

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.

Adult↗
PubMed1999

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.

Activities of Daily Living↗
PubMed1999

The exercise test in Andersen syndrome.

BACKGROUND: Andersen syndrome is a rare form of periodic paralysis (PP) associated with dysmorphic features and potentially fatal cardiac dysrhythmias. To date, no electrodiagnostic abnormalities have been reported that can be used to confirm the presence of PP in this condition. OBJECTIVES: To determine if the exercise test could be used to confirm the diagnosis of PP in Andersen syndrome. To evaluate the exercise test as a means to assess neuromuscular status during treatment. METHODS: We performed the exercise test on 2 patients with Andersen syndrome. In 1 patient, we used a modified version of the test to document responsiveness to treatment with tocainide. RESULTS: Studies in both patients demonstrated a progressive decline in the compound muscle action potential amplitude after exercise that was characteristic of the phenomenon seen in other forms of PP. In 1 patient, improvement in interattack strength and a reduction in the number of attacks of weakness correlated with improvement in the test results. CONCLUSIONS: Our cases demonstrate that the exercise test can confirm the diagnosis of PP in Andersen syndrome. A modified version of exercise testing may also be considered as an objective method for documenting treatment responses in PP.

Abnormalities, Multiple↗
PubMed1999

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.

Adult↗
PubMed1999

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.

Adult↗
PubMed1999

Distal myopathies.

Although muscle disease classically presents with proximal extremity weakness, some myopathic disorders, including several types of muscular dystrophy, result in predominantly, or exclusively, distal muscle involvement. Accurate diagnosis of these relatively uncommon conditions can be challenging for the clinician, because of both the unusual phenotype and the significant overlap in the clinical features of many of these entities. Advances in molecular genetics have permitted a tentative classification of these disorders and have led to the identification of the responsible gene lesion for several of these entities. This review summarizes current understanding of this interesting group of muscular dystrophies and briefly summarizes other myopathies that can present with distal weakness.

Atrophy↗
PubMed1999

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.

Adolescent↗
PubMed1998

Overview of distal myopathies: from the clinical to the molecular.

Five distinct predominantly distal myopathies have been identified with discrete clinical and genetic patterns as follows: (1) Welander myopathy (late adult onset, type 1), with autosomal dominant inheritance and unknown molecular localization; (2) Markesbery-Griggs/Udd myopathies (late adult onset, type 2), with autosomal dominant inheritance and linkage to chromosome 2q; (3) Nonaka myopathy (early adult onset, type 1), with autosomal recessive inheritance and molecular localization to 9p1-q1. Nonaka myopathy is identical to quadriceps-sparing familial inclusion body myopathy; (4) Miyoshi myopathy (early adult onset, type 2), with autosomal recessive inheritance and localization to 2p; (5) Laing myopathy (early onset, type 3), with autosomal dominant inheritance and linkage to chromosome 14. The gene and abnormal gene product have not yet been defined for any of the distal myopathies. However, it is already clear that disorders allelic to the distal myopathies can begin with proximal weakness. Given such major phenotypic variation, it is possible that some of the diseases we regard as distal myopathies may become obsolete. Instead, these conditions may become known by their genetic mutation or abnormal gene product, much like Duchenne and Becker dystrophy.

Age of Onset↗
PubMed1998

Approach to peripheral neuropathy and neuronopathy.

Neuropathic disorders encompass those that affect the neuron's cell body or neuropathies, those affecting the peripheral process, or peripheral neuropathies. The peripheral neuropathies can be broadly subdivided into the myelinopathies and axonopathies. These conditions can be hereditary or acquired. Each of these disorders has distinct clinical features that enable neurologists to recognize the various patterns of presentation. Once a particular pattern is established, further laboratory studies including electrophysiologic testing, nerve biopsy, and blood and cerebrospinal fluid examination can be performed to confirm the clinical impression. Therapy is available in some to correct the underlying disease state or at least to improve symptoms.

Education, Medical, Continuing↗
PubMed1998

Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy.

Acute and chronic inflammatory demyelinating polyneuropathies represent an important group of disorders. Although the acute form is more common, all clinical neurologists will eventually encounter patients with these disorders. Acute inflammatory demyelinating polyneuropathy, or Guillain-Barré syndrome, is the most common cause of acute generalized weakness. Chronic inflammatory demyelinating polyneuropathy, characterized by progressive or relapsing weakness, is important to recognize because it represents a significant number of all initially undiagnosed acquired neuropathies. There are a variety of reasonable therapies available for both of these acquired demyelinating neuropathies. Recently much has been learned about pathogenesis and treatment. This review describes the clinical presentations, laboratory studies, diagnostic criteria, treatment, and prognosis for each disorder.

Demyelinating Diseases↗
PubMed1998

Cryptogenic sensory and sensorimotor polyneuropathies.

Chronic sensory or sensorimotor polyneuropathy is a common clinical problem referred to neurologists. Even with modern diagnostic approaches, up to one-third of them will remain unclassified. Recent studies have provided insight into their clinical spectrum and course. The age of onset tends to be in the sixth to seventh decade of life. Symptoms progress slowly, and most patients present with paresthesias or pain. Cryptogenic polyneuropathies are almost exclusively axonal on clinical, electrophysiologic, and histologic grounds. Overall, the prognosis is favorable, and only a small minority of patients develop significant motor disability or physical incapacitation. Progression to a nonambulatory state essentially never occurs. Successful management should focus on rational pharmacotherapy for painful paresthesias combined with patient education and reassurance.

Education, Medical, Continuing↗
PubMed1998

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.

Adult↗
PubMed1998

Diabetic neuropathic cachexia: report of a recurrent case.

Diabetic neuropathic cachexia is an uncommon peripheral neuropathy associated with diabetes mellitus and characterised by profound weight loss and painful dysaesthesias over the limbs and trunk. The pathophysiological basis of this disorder remains unknown and there have been no published cases of recurrent episodes. A hispanic man who experienced two episodes of diabetic neuropathic cachexia over a seven year period is described.

Adult↗