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At least 271 records · Page 15Linked to original sources
PubMed1983

Chest wall stiffness in patients with chronic respiratory muscle weakness.

Using the weighted spirometer technique we studied chest wall compliance (Cw) in 16 nonobese patients with chronic weakness of the respiratory muscles and 20 healthy control subjects. In order to evaluate the validity of the technique, while Cw was being measured, we monitored thoracoabdominal configuration with 2 pairs of linearized magnetometers and electrical activity of the external oblique with a concentric needle electrode in 3 healthy subjects and 4 patients; in addition, we recorded in 3 subjects the electrical activity from the intercostal muscles and diaphragm throughout the procedure. The method was reproducible within 5.8% and provided Cw values that compared well with those yielded by the relaxation technique. In each subject, the weight-induced shifts in end-expiratory lung volume showed a very good linear correlation with the changes in transrespiratory pressure at end-expiration (r greater than or equal to 0.91). In addition, in none of the subjects tested did the electromyograms reveal any intercostal, diaphragmatic, or abdominal muscle activity at end-expiration, nor did the end-expiratory level ever show a significant departure from the relaxed thoracoabdominal configuration, thus suggesting adequate respiratory muscle relaxation. The reduction in inspiratory muscle force in the patients ranged from 17 to 94% of predicted (mean +/- SE, 43 +/- 6). The decrease in vital capacity, total lung capacity, and functional residual capacity averaged 59, 34, and 15% of predicted, respectively. Both the patient and the control groups showed a large interindividual variability regarding Cw. It varied from 0.117 to 0.258 L/cm H2O (mean +/- SE, 0.162 +/- 0.012) in the patients and from 0.163 to 0.366 L/cm H2O (mean +/- SE, 0.248 +/- 0.013) in the healthy subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗
PubMedDate not supplied

[A case with severe respiratory muscle weakness due to chronic myositis associated with PBC].

We report a 37-year-old woman with slowly developing muscular weakness for 2 years following insidious stiffness of calf muscle. Serum CK was elevated up to 4,207 IU/l. She presented sleepiness, weakness of proximal and truncal muscles and systemic muscular atrophy. While she had not experienced dyspnea, her arterial blood gas analysis revealed extreme hypoxia and hypercapnea due to weakness of respiratory muscles. Echocardiogram showed thinness and hypokinesis of left ventricular wall, and arrhythmia was pointed out by holter ECG. Needle elctromyogram of the proximal muscles exhibited polyphasic units with low amplitude. Muscle biopsy showed degeneration and necrosis of muscle fibers as well as regeneration. Mild infiltration of inflammatory cells was shown. Serological examination showed positive antimitochondrial M2 antibody, especially specific for primary biliary chirrhosis (PBC). She was diagnosed as chronic myositis associated with PBC. Four cases of idiopathic myositis with severe weakness of respiratory muscle, associated with PBC had been reported. These cases and our present case share the similar feature in respect of insidious or chronic course and resistance to therapy. In our present patient, respiration had been supported by BiPAP and she has been successfully improving slowly by oral steroid following 4 courses of methylprednisolone pulse therapy.

Adult↗
PubMed1997

Does parkinsonian action tremor contribute to muscle weakness in Parkinson's disease?

The aim of this study was to see whether action tremor contributes to the weakness which can be measured in some muscles in patients with Parkinson's disease, by preventing fully fused contraction of motor units. Strength and action tremor were recorded during maximal wrist extension in patients when they were on and off antiparkinsonian medication, and in age- and sex-matched healthy subjects. Peak torque and mean rectified EMG levels were reduced by 25% and 30% (n = 7), respectively, when patients were off medication (compared with when they were on medication). In parkinsonian patients off treatment, action tremor was visible in torque and EMG records, and had a frequency of approximately 10 Hz. The absolute amplitude of this tremor was considerably smaller in patients on medication and in control subjects. In patients, medication reduced action tremor in torque and EMG by 37% and 57%, respectively, so that tremor amplitude approached that in normals. Similar changes were seen when action tremor was expressed as % peak torque of % mean rectified EMG. In parkinsonian patients off medication, a 10-Hz synchronizing influence dominates muscle activity at the wrist. The results is an incompletely fused muscle contraction, which is an important factor contributing to the weakness present in the off-medication state. Antiparkinsonian medication releases motor units from the 10-Hz synchronizing influence, enabling higher discharge rates, fused contraction and improved force generation.

Aged↗
PubMed1989

Reversible respiratory muscle weakness in hyperthyroidism.

Breathlessness is a common complaint in patients with hyperthyroidism, and respiratory failure requiring artificial ventilation, although rare, can occur. While a proximal myopathy is frequently recognized, diaphragm muscle function has not hitherto been studied in detail in thyrotoxicosis. The strength of the quadriceps femoris and respiratory muscles was therefore assessed in seven consecutive thyrotoxic patients, on presentation and during medical treatment, when euthyroid. Prior to therapy, reduced quadriceps muscle strength, vital capacity, and global expiratory and inspiratory muscle strength were found. Diaphragmatic weakness was present in one of four patients studied by measuring transdiaphragmatic pressures during maximal sniffs and during bilateral phrenic nerve stimulation at 1 Hz (twitch). After treatment, significant improvement occurred in quadriceps muscle strength, vital capacity, and global respiratory muscle strength. Sniff and twitch transdiaphragmatic pressures also increased significantly. These results indicate that respiratory muscle weakness occurs in hyperthyroidism and that such weakness is reversible with medical treatment. It is important to realize that respiratory muscles may be directly affected when assessing thyrotoxic patients with breathlessness, as severe involvement of the respiratory muscles may cause respiratory failure.

Chronic Disease↗
PubMed1991

In mice, the muscle weakness due to age is absent during stretching.

1. The contractile force was compared in isolated soleus muscles from young (2.5-8 months old) and aged (28-31 months old) mice. Force was measured at 25 degrees C during isometric tetanic contractions during isovelocity stretching and shortening contractions. 2. The normalized isometric force was lower by 13.3% in muscles from aged mice. Muscles from young and aged mice produced 0.951 +/- 0.031 N mg-1 (n = 12) and 0.824 +/- 0.048 N mg-1 (n = 9) respectively. The relaxation time, from 90 to 10% of the tetanic force, of muscles from aged mice was 102.1 +/- 3.7 ms (n = 6), which was longer than that for muscles from young mice, 84.4 +/- 3.8 ms (n = 6) (means +/- S.E.M.). 3. The force during shortening was also reduced in muscles from aged animals by the same proportion as the isometric force. Therefore the force during shortening relative to the isometric force was the same in muscles from young and aged mice. 4. During rapid stretching soleus muscles from aged mice produced a similar force to those from young mice. Therefore stretch can remove the weakness in muscles of aged mice. 5. These changes in muscles from aged mice are similar to those produced when inorganic phosphate (Pi) levels are raised, in skinned rabbit psoas fibres, or during fatigue or with low intracellular pH (pHi), in frog muscle. It is possible therefore that the force loss due to ageing may be due to a higher Pi level or a lower pHi.

Aging↗
PubMed1992

An unusual presentation of polymyalgia rheumatica with severe muscle weakness.

An 83-year-old woman suddenly developed profound weakness of proximal and distal muscles in both upper limbs. Electromyography revealed abnormal changes but serum creatine kinase was normal. The weakness responded dramatically to steroid therapy. These unusual features of polymyalgia rheumatica are discussed.

Aged↗
PubMed2004

Interventions for sarcopenia and muscle weakness in older people.

OBJECTIVE: three major strategies have been tested for combating the losses in muscle mass and strength that accompany ageing. Those strategies are testosterone replacement for men, growth hormone replacement and resistance exercise training. This review will cover the risks and benefits associated with each of these interventions. METHODS: searches of PubMed and Web of Science through May 2004 yielded 85 relevant citations for the following descriptors: sarcopenia, aging/ageing, elderly, testosterone, hormone replacement, growth hormone, resistance training, exercise, muscle mass, nutrition and strength. RESULTS AND CONCLUSIONS: testosterone replacement in elderly hypogonadal men produces only modest increases in muscle mass and strength, which are observed in some studies and not in others. Higher doses have not been given for fear of accelerating prostate cancer. Growth hormone replacement in elderly subjects produces a high incidence of side-effects, does not increase strength and does not augment strength gains resulting from resistance training. Some alternate strategies for stimulating the growth hormone/insulin-like growth factor (IGF) pathway continue to hold promise. The latter include growth hormone releasing hormone (GHRH) and the complex of IGF-I with its major circulating binding protein (IGF-I/IGFBP-3). Resistance training remains the most effective intervention for increasing muscle mass and strength in older people. Elderly people have reduced food intake and increased protein requirements. As a result, adequate nutrition is sometimes a barrier to obtaining full benefits from resistance training in this population.

Adult↗
PubMed2006

Thigh muscle weakness in ACL-deficient knees persists without structured rehabilitation.

UNLABELLED: We evaluated whether quadriceps and hamstrings weakness depended on chronicity in amateur athletes with anterior cruciate ligament deficiencies. We hypothesized that the weakness would not recover to the level of healthy control subjects without structured rehabilitation. Secondarily, we asked whether quadriceps and hamstrings side-to-side percent asymmetry in strength was consistent at different stages of chronicity. Thirty-six male amateur athletes forming equal groups of short, intermediate, and long chronicity (mean, 4, 12, and 56 months, respectively) were tested isokinetically against control subjects at 60 degrees per second. Weakness was substantial in both muscle groups and at all times ranging from 32% to 21% compared with the control subjects. However, side-to-side deficits revealed a linear trend of lessening with time. The quadriceps had greater side-to-side asymmetry that ranged from 23% to 10%, whereas the hamstrings asymmetry ranged from 14% to almost 0%. Acquiring symmetric strength earlier than 1 year after injury only occurred in the hamstrings. It can be inferred that participation in organized rehabilitation would minimize the detrimental effects of anterior cruciate ligament rupture on thigh muscle strength. LEVEL OF EVIDENCE: Prognostic Study, Level II.

Anterior Cruciate Ligament Injuries↗
PubMedDate not supplied

Perineurial cell ensheathement of muscle fibers: a new syndrome of fatigable muscle weakness mimicking myasthenia gravis.

Many newly discovered pathological and physiological variants of neuromuscular junction function have been identified. We report a case of a myasthenia gravis-like syndrome with onset of ptosis at age six years and eventual evaluation for peripheral weakness twenty years later. Subsequent muscle biopsy showed a previously unreported finding of perineurial cell ensheathement of the muscle fibers. We suggest that the ensheathement of the muscle cells by perineurial cells may alter the microenvironment interfering with neuromuscular transmission.

Adult↗
PubMed1993

[Muscle weakness].

A 61 year old man complained initially about pain in the left lower leg with increasing swelling of the entire left leg. A slight swelling of the left ankle and knee and an erythematous skin change of 5 cm diameter developed and disappeared after a few hours. Two days later the patient complained about a sudden and massive weakness of the proximal skeletal muscles, progressive disturbance of swallowing, hoarseness and dark red to bluish erythematous skin eruptions on the right knee and buttock. An elevated creatinine-kinase and lactate-dehydrogenase were found. Dermatomyositis was diagnosed and treatment with high dose steroids initiated. Under this treatment the patients condition deteriorated dramatically. A treatment with plasmapheresis and cyclophosphamide was begun. A significant improvement occurred over three weeks. The patient was discharged, rehabilitated and remains free of symptoms on 10 mg cortisone. A neoplasm has so far not been detected.

Acute Disease↗