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Biomedical subjects

Richard J Barohn

Publications and source records attributed to Richard J Barohn.

11 recordsLinked to original sources

Primary lateral sclerosis.

The spectrum of motor neuron diseases ranges from disorders that clinically are limited to lower motor neurons to those that exclusively affect upper motor neurons. Primary lateral sclerosis (PLS) is the designation for the syndrome of progressive upper motor neuron dysfunction when no other etiology is identified. Distinction between PLS and the more common amyotrophic lateral sclerosis (ALS) relies primarily on recognition of their symptoms and signs, as well as on ancillary, although non-specific, laboratory data. In this review, we survey the history of PLS from the initial descriptions to the present. We discuss the role of laboratory, electrodiagnostic, and imaging studies in excluding other diagnoses; the findings from major case series of PLS patients; and proposed diagnostic criteria. Consistent differences are evident in patients classified as PLS compared to those with ALS, indicating that, despite its limitations, this clinical designation retains important utility.

Age of Onset↗

Supportive care for patients with Guillain-Barré syndrome.

A multidisciplinary consensus group searched MEDLINE from 1966 to May 2003, extracted relevant references, and prepared recommendations on supportive care for Guillain-Barré syndrome. In the absence of randomized controlled trials, we agreed on recommendations by consensus based on observational studies and expert opinion. In the acute phase in bed-bound adult patients, the group recommended the use of heparin and graduated pressure stockings to prevent deep vein thrombosis, monitoring for blood pressure, pulse, autonomic disturbances, and respiratory failure, and the timely institution of artificial ventilation and tracheostomy. Pain management is difficult, but carbamazepine or gabapentin may help. The cautious use of narcotic analgesics may be needed. Disabled patients should be treated by a multidisciplinary rehabilitation team and should receive an assistive exercise program. Persistent fatigue following Guillain-Barré syndrome is common and may be helped by an exercise program. Because of a very small and possibly only theoretical increase in the risk of recurrence following immunization, the need for immunization should be reviewed on an individual basis. More research is needed to identify optimal methods for all aspects of supportive care.

Autonomic Nervous System Diseases↗

Interferon-alpha/beta-mediated innate immune mechanisms in dermatomyositis.

Dermatomyositis has been modeled as an autoimmune disease largely mediated by the adaptive immune system, including a local humorally mediated response with B and T helper cell muscle infiltration, antibody and complement-mediated injury of capillaries, and perifascicular atrophy of muscle fibers caused by ischemia. To further understand the pathophysiology of dermatomyositis, we used microarrays, computational methods, immunohistochemistry and electron microscopy to study muscle specimens from 67 patients, 54 with inflammatory myopathies, 14 with dermatomyositis. In dermatomyositis, genes induced by interferon-alpha/beta were highly overexpressed, and immunohistochemistry for the interferon-alpha/beta inducible protein MxA showed dense staining of perifascicular, and, sometimes all myofibers in 8/14 patients and on capillaries in 13/14 patients. Of 36 patients with other inflammatory myopathies, 1 patient had faint MxA staining of myofibers and 3 of capillaries. Plasmacytoid dendritic cells, potent CD4+ cellular sources of interferon-alpha, are present in substantial numbers in dermatomyositis and may account for most of the cells previously identified as T helper cells. In addition to an adaptive immune response, an innate immune response characterized by plasmacytoid dendritic cell infiltration and interferon-alpha/beta inducible gene and protein expression may be an important part of the pathogenesis of dermatomyositis, as it appears to be in systemic lupus erythematosus.

Adult↗

Management of myasthenia gravis.

Although once a severe and often fatal illness, myasthenia gravis can now be well managed with several relatively safe and effective therapies. Management involves a graded approach, beginning with cholinesterase inhibitors for mild symptoms and advancing to immunomodulating medications for more severe weakness. There are several immunomodulating agents from which to choose; selection is based largely on time to clinical effect and adverse effects. This review will discuss the selection and use of therapies for patients with myasthenia gravis.

Cholinesterase Inhibitors↗

Challenges in the identification of cobalamin-deficiency polyneuropathy.

BACKGROUND: Diagnosing cobalamin (Cbl) deficiency as a cause of polyneuropathy (PN) is problematic, as the frequency of both disorders increases with age, and serum Cbl levels can be difficult to interpret. OBJECTIVES: To identify unique clinical or laboratory features among PN patients with Cbl deficiency and to examine the role of testing of serum metabolite levels in the identification of Cbl deficiency. DESIGN: Cohort survey comparing patients with Cbl deficiency and cryptogenic PN identified during a 2-year period. Cobalamin deficiency was diagnosed using low serum Cbl levels or elevated serum methylmalonic acid or homocysteine levels. SETTING: Academic neuromuscular clinic. RESULTS: Of 324 PN patients, 27 were diagnosed as having Cbl deficiency. Twelve had Cbl levels within the normal range, but elevated serum metabolite levels. Compared with patients with cryptogenic sensory/sensorimotor PN, those with Cbl deficiency were more likely to have concomitant involvement of the upper and lower extremities and experience symptom onset in the hands and a sudden onset of symptoms (P<.005). These differences were seen regardless of whether Cbl deficiency was defined using low Cbl levels or elevated serum metabolite levels. Autoimmune pernicious anemia was identified in 6 (50%) of 12 Cbl-deficient patients with normal serum Cbl levels. The patients with PN and Cbl deficiency showed little objective improvement after parenteral replacement therapy; however, progression occurred less often in these patients compared with those with cryptogenic sensory/sensorimotor PN (P =.02). CONCLUSIONS: This study highlights the challenges of proving that Cbl deficiency is the cause for PN and identifies clinical features that suggest Cbl-deficiency PN. Testing of serum metabolite levels may identify Cbl deficiency in some patients with normal serum Cbl levels.

Adult↗

Late-onset distal muscular dystrophy affecting the posterior calves.

Miyoshi myopathy, caused by mutations in the membrane protein dysferlin, is the most common muscular dystrophy that presents in the posterior calves. Its onset is before the age of 30 years and it is associated with marked elevations of serum creatine kinase (CK). In contrast, little is known about calf myopathies with onset after the age of 30, and it is not clear whether such patients have a dysferlinopathy. We describe five patients with a myopathy predominantly affecting the calf muscles, with onset after the age of 30. Muscle tissue was analyzed by immunoblot for dystrophin and dysferlin. All five had normal dysferlin but one had a dystrophinopathy. Serum CK levels ranged from 3 to 15 times the upper limit of normal. In contrast, all of 13 patients presenting before age 30 with calf weakness had a dysferlinopathy. Thus, isolated calf atrophy and weakness with onset after age 30, and associated with serum CK levels that are only moderately elevated, represents a distinct myopathy phenotype. Most of these cases are sporadic, although the overall phenotype appears genetically heterogeneous and dysferlinopathy is uncommon.

Adult↗

Current concepts and controversy in chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired, immune-mediated demyelinating neuropathy. It is the most common treatable acquired polyneuropathy and represents a significant number of initially undiagnosed neuropathy patients. This article reviews the common clinical, laboratory, and electrodiagnostic features of CIDP. In addition, current areas of uncertainty are discussed.

Adrenal Cortex Hormones↗

Standards of measurements in myasthenia gravis.

In 1997, the Medical Scientific Advisory Board of the Myasthenia Gravis Foundation of America formed a Task Force to develop classification and outcome measures for myasthenia gravis (MG). The goal of the Task Force was to achieve uniformity in recording and reporting clinical trials and outcomes research. The Task Force met frequently over a three-year period, obtained input from national and international experts, and produced a consensus document on recommendations for MG clinical research standards. In this article, the essential elements of the Task Force's recommendations will be summarized. In addition, several other MG measurement tools that are in various stages of development are mentioned.

Activities of Daily Living↗

Randomized, controlled trial of intravenous immunoglobulin in myasthenia gravis.

We initiated a randomized, double-blinded, placebo-controlled trial of intravenous immunoglobulin (IVIG) treatment in myasthenia gravis (MG). Patients received IVIG 2 gm/kg at induction and 1 gm/kg after 3 weeks vs. 5% albumin placebo. The primary efficacy measurement was the change in the quantitative MG Score (QMG) at day 42. Fifteen patients were enrolled (6 to IVIG; 9 to placebo) before the study was terminated because of insufficient IVIG inventories. At day 42, there was no significant difference in primary or secondary outcome measurements between the two groups. In a subsequent 6-week open-label study of IVIG, positive trends were observed.

Adult↗