In myotonic dystrophy, there is resistance of forearm muscle to physiologic concentrations of insulin. To determine whether this resistance is due to a shift in the dose-response curve resulting from decreased numbers of insulin receptors, we measured the effects of supraphysiologic insulinization (200 mu U per kilogram per minute) on the uptake of glucose by forearm muscle in three patients with myotonic dystrophy and five denervated patients with comparable wasting. Although insulin levels were higher in patients with myotonic dystrophy than in controls, peak glucose uptake remained significantly lower in myotonic dystrophy patients. The findings are consistent with a postinsulin receptor defect of muscle and with altered membrane function in myotonic dystrophy.

Adult↗

PubMed1980

3-methylhistidine excretion in myotonic dystrophy.

3-Methylhistidine (3-MH) excretion reflects the rate of muscle protein catabolism, since 3-MH occurs almost exclusively in muscle actin and myosin and is not reutilized or catabolized. We studied 3-MH excretion in 9 patients with myotonic dystrophy, 8 normals, and 10 disease controls with Duchenne dystrophy and other disorders. 3-MH excretion was expressed relative to muscle mass as determined by both urinary creatinine and total body potassium (40K method). Absolute 3-MH excretion was decreased in myotonic dystrophy patients but was normal when related to muscle mass. The finding of normal 3-MH excretion in myotonic dystrophy suggests that the muscle wasting in this disorder results from impaired anabolic processes rather than accelerated muscle destruction.

Adolescent↗

PubMed1980

Heterozygous C2-deficiency and myasthenia gravis.

Complement deficiency states in myasthenia gravis (MG) have not been reported previously. We describe a 19-year-old woman with typical MG and heterozygous C2 deficiency, along with HLA typing of the patient and her immediate family.

Acetylcholine↗

PubMed1980

Recovery from the locked-in syndrome.

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Adult↗

PubMed1980

Arrhythmic complications in the Guillain-Barré syndrome.

The occurrence of cardiac arrhythmia in Guillain-Barré syndrome (GBS) was examined in a retrospective study of 16 consecutive patients with GBS admitted to an intensive care unit primarily for respiratory insufficiency, Bradyarrhythmias, including sinus arrest or atrioventricular block rhythms, and/or tachyarrhythmias, supraventricular as well as ventricular, were observed in 13 patients. Two patients required pacemaker insertion because of recurrent asystolic episodes. Of the four fatalities, however, none were considered cardiac in origin. While clinically apparent autonomic nervous system dysfunction accompanied many of the observed arrhythmias and may be involved in arrhythmogenesis, these patients also suffered from pulmonary, infectious, and thromboembolic complications that could produce similar arrhythmic complications and must also be considered whenever such arrhythmias are seen.

Adolescent↗

PubMed1979

Orbicularis fatigue: the 'peek' sign of myasthenia gravis.

Three patients with myasthenia gravis demonstrated a distinctive sign of orbicularis fatigue. After momentary opposition on gentle sustained lid closure, the lid margins separated, resulting in widening of the palpebral fissure and scleral exposure. The patient thus appeared to "peek" at the examiner. The "peek" sign was not observed in 200 control patients and in 49 of 50 patients with facial weakness secondary to a spectrum of neuromuscular disorders. Three of 25 patients with myasthenia gravis displayed this sign, and in one patient it was the major diagnostic finding. The presence of the "peek" sign suggests the diagnosis of myasthenia gravis.

Adult↗

PubMed1979

A 'firm' system for graduate training in general internal medicine.

The faculty of the Department of Medicine at Cleveland Metropolitan General Hospital has responded to the challenge of fostering general internal medicine in a graduate training program by organizing a "firm" system of medical care which has appealed to academic internists with broad interests in clinical medicine. This firm system consists of four medical teams which care for distinct patient populations, closely integrating their outpatient and inpatient care. The firms are made up of all the house staff in training in internal medicine together with senior and junior faculty members who are directors for the firms. Medical students in general medicine are also assigned to firms. This firm system is relatively simple to understand and establish and is readily applicable to other academic departments with general medical responsibilities.

Education, Medical, Graduate↗

PubMed1979

Regulation of plasma potassium in hyperkalemic periodic paralysis.

Hyperkalemic periodic paralysis is frequently considered a disorder in which episodes of weakness and an attendant rise in plasma potassium interrupt a baseline of normal strength and potassium. We studied venous potassium throughout a 36-hour period in two patients with hyperkalemic periodic paralysis and in nine normals under rigidly controlled conditions. At no time did the patients with periodic paralysis have an attack of weakness, but their mean potassium concentrations were above the normal range for 33 to 36 hours. In hyperkalemic periodic paralysis, the postprandial change in potassium relative to insulin release exceeded normal. There appears to be a continuous alteration in potassium regulation in our patients with hyperkalemic periodic paralysis.

Female↗

PubMed1978

Effects of acetazolamide on myotonia.

Myotonia can occur in the periodic paralyses, particularly the hyperkalemic form. The beneficial response to acetazolamide in hypokalemic and hyperkalemic periodic paralysis has led us to study the effect of acetazolamide in 9 patients with disorders having myotonia as the major problem, 7 with myotonia congenita and 2 with paramyotonia congenita. Patients were studied before acetazolamide administration with glucose and potassium loading tests. All patients had an increase in myotonia with potassium, but no weakness occurred with either test. Acetazolamide treatment decreased myotonia in all patients and in 3 proved the most satisfactory therapy. Side-effects during acetazolamide therapy included paresthesias in 5 patients and renal calculus in 1. Flaccid weakness occurred in a patient with paramyotonia congenita. Acetazolamide treatment was associated in all patients with partially compensated metabolic acidosis and lowering of serum potassium within the normal range. Kaliuresis was also noted during introduction of therapy. Acetazolamide appears to be an acceptable treatment for occasional patients with myotonia who are unresponsive to or intolerant of other therapies.

Acetazolamide↗

PubMed1978

Metabolic implications of distal atrophy. Carbohydrate metabolism in centronuclear myopathy.

Centronuclear myopathy, like myotonic dystrophy, is characterized by muscle wasting and type 1 fiber atrophy. To determine whether this disorder might include a derangement in carbohydrate metabolism similar to that in myotonic dystrophy, 3 comparably wasted patients with centronuclear myopathy, myotonic dystrophy, and neurogenic atrophy were investigated. The patient with centronuclear myopathy had mild glucose intolerance and hypoinsulinemia after oral glucose ingestion in bold contrast to the normal glucose tolerance and hyperinsulinemia observed in the myotonic dystrophy patient. No abnormality was seen in oral glucose tolerance in the patient with neurogenic atrophy, and all 3 patients had normal insulin tolerance. Forearm insulin infusion demonstrated normal stimulation of muscle glucose uptake in the patients with centronuclear myopathy and neurogenic atrophy in contrast to the markedly diminished response to insulin seen in the patient with myotonic dystrophy. These data indicate that neither distal wasting or type 1 fiber atrophy are responsible for the abnormalities in carbohydrate metabolism in myotonic dystrophy.

Adult↗

PubMed1978

Decreased insulin sensitivity of forearm muscle in myotonic dystrophy.

Previous studies of patients with myotonic dystrophy have demonstrated hyperinsulinism after glucose loading. This hyperinsulinism has been attributed by some investigators to tissue insulin resistance. We have directly studied insulin sensitivity of forearm muscle in patients having such hyperinsulinism. The effect of an intrabrachial arterial insulin infusion (100 mu U/kg per min) on glucose uptake was determined in six cases of myotonic dystrophy, six normal subjects, and in seven disease control subjects with myotonia or wasting from other disorders. There was no significant difference in insulin tolerance comparing myotonic dystrophy patients to the normal and disease control groups. Glucose tolerance and basal insulin levels were normal in the myotonic dystrophy patients, but hyperinsulinism occurred after glucose ingestion. After 25 min of intra-arterial insulin, the mean peak muscle glucose uptake in myotonic dystrophy was 2.54 +/- 0.54 mu mol/min per 100 ml forearm compared to 5.24 +/- 0.86 mu mol/min per 100 ml for disease controls (P is less than 0.05). Myotonic dystrophy patients showed a peak glucose uptake increment of only 2.6 +/- 0.2-fold over basal contrasted with the disease control value of 6.5 +/- 1.0-fold (P is less than 0.02) and the normal control value of 8.8 +/- 1.1-fold (P is less than 0.01). Thus, there was an absolute as well as a relative decrease in muscle insulin sensitivity in myotonic dystrophy patients compared to both control groups. The peak increments in arterio-superficial venous glucose concentration differences after insulin infusion were not significantly different comparing myotonic dystrophy and control groups. These data suggest that in myotonic dystrophy, there is insulin insensitivity of skeletal muscle.

Adult↗

PubMed1978

Hereditary paroxysmal ataxia: response to acetazolamide.

From early childhood, eight patients in a kindred had paroxysmal bouts of ataxia, dysarthria, and nystagmus. The disorder was inherited as an autosomal dominant. Attacks occurred weekly and lasted 1 to 6 hours; there were slight cerebellar signs between attacks. Although the etiology was not determined, a serendipitous trial of acetazolamide completely abolished attacks, and all patients have remained free of attacks for as long as 5 years.

Acetazolamide↗

PubMed1978

Note on plasma exchange therapy in Refsum's disease.

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Adult↗

PubMed1977

Distal myopathy: electron microscopic and histochemical studies.

This report describes the clinical, laboratory, and muscle biopsy histochemical and electron microscopic studies of one inherited and two sporadic cases of distal myopathy. Histopathologic and histochemical studies showed numerous myopathic alterations and no significant evidence of denervation. Electron microscopic studies showed a broad spectrum of nonspecific alterations similar to those in other forms of muscular dystrophy. Autophagic vacuoles were prominent in all cases. The inherited case was characterized by an unusual focal granular degeneration that, ultrastructurally, was composed of homogeneous fine granules devoid of other organelles or myofilamens.

Adult↗