Subjective Muscle Weakness Research Articles

Characterizing Mechanical Changes in the Biceps Brachii Muscle in Mild Facioscapulohumeral Muscular Dystrophy Using Shear Wave Elastography.

There is no general consensus on evaluating disease progression in facioscapulohumeral muscular dystrophy (FSHD). Recently, shear wave elastography (SWE) has been proposed as a noninvasive diagnostic tool to assess muscle stiffness in vivo. Therefore, this study aimed to characterize biceps brachii (BB) muscle mechanics in mild-FSHD patients using SWE. Eight patients with mild FSHD, the BB were assessed using SWE, surface electromyography (sEMG), elbow moment measurements during rest, maximum voluntary contraction (MVC), and isometric ramp contractions at 25%, 50%, and 75% MVC across five elbow positions (60°, 90°, 120°, 150°, and 180° flexion). The mean absolute percentage deviation (MAPD) was analyzed as a measure of force control during ramp contractions. The shear elastic modulus of the BB in FSHD patients increased from flexed to extended elbow positions (e.g., p < 0.001 at 25% MVC) and with increasing contraction intensity (e.g., p < 0.001 at 60°). MAPD was highly variable, indicating significant deviation from target values during ramp contractions. SWE in mild FSHD is influenced by contraction level and joint angle, similar to findings of previous studies in healthy subjects. Moreover, altered force control could relate to the subjective muscle weakness reported by patients with dystrophies.

OA15 Missing the wood(-y induration) for the trees

OA15 Missing the wood(-y induration) for the trees

EP03 Parechovirus in a pathologist

Case report - IntroductionA 42-year-old pathologist presented with a 1-week history of muscle pain and subjective weakness. CK level on 2 occasions was >3000.The patient was systemically well with no past medical history, medication, or foreign travel. He had 1-day history of shivering with no recorded pyrexia. He reported pain in his proximal muscles and neck and subjective muscle weakness and lack of finger dexterity with no objective findings. Case report - Case descriptionAutoantibody panel and inflammatory markers were performed which were normal. Full blood count with differential white cell count including eosinophils was normal. There was a modest rise in transaminases. Myositis panel was negative. Full viral screen was positive for parechovirus with titre of 30 on several samples. MRI proximal musculature showed increased fluid signal in the perifascial region of both thighs primarily involving the hamstrings, not definitive for myositis but suggestive of fasciitis.Case report - DiscussionParechovirus is a picornavirus, often causing mild gastrointestinal or respiratory illness but has been associated with epidemic myalgia and myositis during outbreaks of parechovirus in a Japanese population.The patient improved spontaneously with CK reduced to 187 and improved symptoms after 1 week. We expect a good outcome and will review on patient's request if necessary.Case report - Key learning pointsParechovirus can cause myofasciitis which is usually mild and self-limiting. It can be associated with elevated CK, transaminases and MRI findings and can be confirmed on respiratory viral swab.

Responses to progressive exercise in subjects with chronic dyspnea and inspiratory muscle weakness

Inspiratory muscle weakness (IMW) is a potential cause of exertional dyspnea frequently under-appreciated in clinical practice. Cardiopulmonary exercise testing (CPET) is usually requested as part of the work-up for unexplained breathlessness, but the specific pattern of exercise responses ascribed to IMW is insufficiently characterized. To identify the physiological and sensorial responses to progressive exercise in dyspneic patients with IMW without concomitant cardiorespiratory or neuromuscular diseases. Twenty-three subjects (18 females, 55.2±16.9 years) complaining of chronic daily life dyspnea (mMRC = 3 [2-3]) plus maximal inspiratory pressure < the lower limit of normal and 12 matched controls performed incremental cycling CPET. FEV1/FVC<0.7, significant abnormalities in chest CT or echocardiography, and/or an established diagnosis of neuromuscular disease were among the exclusion criteria. Patients presented with reduced aerobic capacity (peak V̇O2: 79±26 vs 116±21 %predicted), a tachypneic breathing pattern (peak breathing frequency/tidal volume = 38.4 ± 22.7 vs 21.7 ± 14.2 breaths/min/L) and exercise-induced inspiratory capacity reduction (-0.17 ± 0.33 vs 0.10 ± 0.30 L) (all P < .05) compared to controls. In addition, higher ventilatory response (ΔV̇E/ΔV̇CO2 = 34.1±6.7 vs 27.0±2.3 L/L) and symptomatic burden (dyspnea and leg discomfort) to the imposed workload were observed in patients. Of note, pulse oximetry was similar between groups. Reduced aerobic capacity in the context of a tachypneic breathing pattern, inspiratory capacity reduction and preserved oxygen exchange during progressive exercise should raise the suspicion of inspiratory muscle weakness in subjects with otherwise unexplained breathlessness.

SAT-203 Misleading Diagnosis of Cushing’s Syndrome on Pramipexole

We present an intriguing case of a patient incorrectly diagnosed with Cushing’s disease secondary to pramipexole use for restless leg syndrome (RLS). 61-year-old male with symptoms of 55 lb weight gain, progressive fatigue, and subjective muscle weakness presented to endocrinology office for work-up of possible Cushing’s syndrome. Physical exam was significant for mild facial plethora, purple striae, and central obesity. Patient’s history includes diagnosis of prolactin-producing pituitary microadenoma 30 years ago treated with bromocriptine with normalization of prolactin and resolution of adenoma. Patient notes ten years ago, he was started on pramipexole 1 mg TID for severe RLS. Given patient’s clinical symptoms he underwent hormonal testing which was notable for an abnormal 1 mg ONDST with morning cortisol 2.44 mcg/dL (normal < 1.8 mg/dL) and two abnormal late night salivary cortisol 0.177 mcg/dL and 0.199 mcg/dL (normal < 0.122). Repeat MRI showed a 0.4 cm hypoenhancing lesion in the left side of the anterior pituitary gland. Patient was referred for IPSS. His central-to-peripheral plasma ACTH ratio was as follows: before CRH administration: left 5.8, right 1.2; after CRH administration: left 16.4, right 2.7. These results demonstrated positive IPSS indicating centralization or a pituitary source of ACTH excess. Patient was going to be referred to neurosurgery for left pituitary adenoma resection, but literature search revealed a study showing pramipexole causing an increase in cortisol levels in physiologic studies involving healthy subjects. Due to these findings, labs were repeated while holding pramipexole. His morning cortisol and ACTH levels were normal. Late night salivary cortisol x3 were normal: 0.038, 0.071, and 0.024 mcg/dL (normal < 0.090 mcg/dL). The 24 hour urine free cortisol x2 was also normal. These negative biochemical findings showed no evidence of hypercortisolism off of pramipexole. This further complicated the case as the patient had positive IPSS. In order to help exclude the diagnosis of an ACTH secreting pituitary tumor, a DDAVP stimulation test was performed showing a normal response. Based on these tests it was concluded he does not have Cushing’s and that his hypercortisolism was related to pramipexole use. Repeat brain MRI showed no structural evidence of any pituitary lesion. We report a very rare case of pramipexole use leading to a false diagnosis of Cushing’s syndrome. This was fortunately identified prior to patient undergoing unnecessary surgery. We recommend awareness of pramipexole use associated with hypercortisolism to prevent incorrect diagnosis of Cushing’s syndrome.Schilling, J. C., Adamus, W. S., & Palluk, R. (1992). Neuroendocrine and side effect profile of pramipexole, a new dopamine receptor agonist, in humans. Clinical Pharmacology & Therapeutics, 51(5), 541-548.

37-Year-Old Man With Fatigue and Erectile Dysfunction

37-Year-Old Man With Fatigue and Erectile Dysfunction

Assessment of Respiratory Muscle Weakness in Subjects With Neuromuscular Disease.

Neuromuscular diseases (NMD) are a group of rare heterogeneous disorders that may be accompanied by respiratory muscle weakness. The simplest measurements of respiratory muscle strength are maximum inspiratory pressure (PImax) and maximum expiratory pressure (PEmax) of the mouth. Inspiratory muscle weakness can also be evaluated by the sniff test (sniff nasal inspiratory pressure method). This study tested the agreements in PImax and PEmax (measured by using a plethysmograph and portable equipment) as well as the correlations of PImax and PEmax by using the sniff nasal inspiratory pressure method, lung function, and arterial blood gas parameters in subjects with NMD. This prospective, noninterventional study measured respiratory parameters in all the subjects with NMD who underwent measurement of maximum respiratory pressures. A total of 55 subjects with NMD were included. There were no statistically significant differences in PImax and PEmax measured by using a plethysmograph and portable equipment. Moreover, PImax showed a good correlation with the sniff nasal inspiratory pressure method. Measurements of PImax and PEmax by using portable equipment were equivalent to those performed by using the accepted standard, plethysmography, in the subjects with NMD. Noninvasive evaluation of the sniff test with the portable equipment correlates with PImax, which makes this approach a good method for measuring the maximum strength of inspiratory muscles in patients with NMD.

Abstract P072: Who Becomes Weak on Statins? Effect Modification Exposed in a RCT by Risk Factor Compounding

Background: Some patients develop muscle weakness ( MW ) on statins but MW has not been affirmed in RCTs. Existing evidence suggests muscle problems may arise more commonly in those who are older, female, have a history of muscle problems, or exercise more. We assessed whether statin effects on MW can be unmasked by attending to effect modification, assessing if pairing of known risk factors ( RFs ) may amplify and expose MW in subgroups. Method: In a double blind RCT, 1016 adults (68% men) without DM or CVD were randomized equally to simvastatin 20mg, pravastatin 40mg or placebo for 6 months. MW was rated at baseline (0-10) and as change from baseline (-2 to +2). T-tests of difference in self-rated change in MW compared placebo to each statin arm, examining hypothesized vulnerable subgroups based on a) paired age/sex vulnerability (female + age &gt;65); and paired weakness+exercise vulnerability (baseline weakness rated &gt;0, + regular exercise &gt;5x/week). Results: Statins vs placebo did not increase MW in the full sample. Trends were not significant in those with individual RFs. Statins significantly increased MW in both risk-factor pairings ( Table ). In older women, mean MW increase on statins rose as age advanced further, from 0.19 (age &gt;65) to 0.26 (&gt;70), 0.37 (&gt;75), and 1 (&gt;80), while MW on placebo remained unchanged or improved. Statins also increased MW in subjects with any baseline MW (rated &gt;0) who engaged in regular exercise: Effects were larger, but the subgroup smaller. Discussion: In subgroups suggested by coupling of RFs in existing literature, analysis identifies significantly increased MW with statins vs placebo, providing, to our knowledge, the first RCT evidence of MW on statins. Older women represent an important group in whom MW increased. In those with any baseline MW who exercise regularly (as may be recommended), MW worsened with statins. Findings were consistent across statin randomization arms. This may offer an approach to better unmask adverse effects in RCTs.

Voluntary Activation of the Knee Extensors in Chronic Poststroke Subjects

To assess the extent to which knee extensor muscle weakness in subjects with chronic mild to moderate poststroke hemiparesis is caused by a decreased voluntary activation. Forty community dwelling and ambulant men and women (mean age, 59.8 +/- 5.5 yrs) with residual hemiparesis (19.2 +/- 8.5 mos poststroke) were tested. Torque measurements were performed on a computerized dynamometer and the superimposed electrical stimulation technique was used to assess voluntary activation of the knee extensors in both the paretic and the nonparetic lower limbs. The mean voluntary activation ratio of the knee extensors in the nonparetic and paretic leg was 0.97 +/- 0.04 and 0.86 +/- 0.13, respectively. Subjects who had a greater relative weakness, implying a more pronounced poststroke impairment, also had lower voluntary activation ratios. The mean percentage difference in total torque between the nonparetic and the paretic knee extensors after the electrical stimulation was 36.4% +/- 17.0%. Paretic knee extensor muscle weakness in chronic poststroke subjects is only partially explained by a reduced voluntary activation ability, indicating that other neuromuscular structural or functional factors contribute to poststroke hemiparetic muscle weakness.

FREQUENCY AND SEVERITY OF MUSCULOSKELETAL SYMPTOMS IN HUMANS DURING AN OUTBREAK OF TRICHINELLOSIS CAUSED BY TRICHINELLA BRITOVI

Musculoskeletal symptoms such as myalgia are well-known features in the course of trichinellosis; however, the characteristics of musculoskeletal findings have been described in detail in only 1 study. The present study was aimed to determine the joint and muscle symptoms in subjects diagnosed with acute trichinellosis at our rheumatology unit during a Trichinella britovi outbreak that occurred in Izmir, Turkey, in 2004. In total, 98 patients (55 females, 43 males; mean age 32.3 +/- 10.9 yr) were included in the study. A detailed history and full musculoskeletal examination were obtained in each patient. A self-administered questionnaire developed for recording the musculoskeletal symptoms was completed monthly until all the symptoms were resolved. Pain at the joints, restriction of movements (in shoulders, elbows, wrists, knees, ankles, and temporomandibular joints), myalgia, and muscle weakness (neck and shoulder girdle, muscles of the upper and forearm, back, thigh, and calf muscles) were assessed in every patient. Eosinophil counts, serum levels of creatine kinase, and lactate dehydrogenase also were analyzed. The most frequent musculoskeletal symptoms were muscle pain (86 cases [87.8%]), joint pain (83 [84.7%]), subjective muscle weakness (75 [76.5%]), and restriction of joint movements (63 [64.3%]). Calves, upper arm, neck and shoulder girdle, and forearms were the most affected muscle groups. Muscle pain was reported more frequently in the upper than in the lower extremities and during activity. The most frequent painful joints were shoulders, knees, wrists, and ankles. Upper extremity joints were affected more frequently than the lower extremity joints (77.6 vs. 70.4%). Joint pain occurred more frequently at rest. Both muscle weakness and restriction of joint movements were reported in and around the most frequently affected regions. No evidence of arthritis and objective muscle weakness was noted on physical examination in any patient. Musculoskeletal symptoms in the course of T. britovi infection are frequent but with an excellent prognosis. Joint pain in people suffering from acute trichinellosis may occur more frequently than reported previously.

Results of surgical treatment of tarsal tunnel syndrome

The purpose of this study is to present our results after surgical treatment of patients suffering from a tarsal tunnel syndrome. In 75 patients 77 surgical decompressions of the tarsal tunnel were performed. All patients were treated conservatively for at least 6 months prior to surgical intervention. A positive local anesthesia test prior to the operation was mandatory for all patients. The results were evaluated according to pain at rest, pain during walking, weakness, and according to a modified AOFAS forefoot score. Follow-up ranged from 6 to 100 months (average 39 months). Only 43 out of 75 patients were subjectively satisfied and would undergo the procedure again. While pain at rest decreased in 53 patients, pain during walking decreased only in 22 cases. Subjective muscle weakness decreased in six patients—however, this parameter was not a clinical relevant problem in most of the patients. At the time of follow-up the modified AOFAS score was 44 (range 15–75). Surgical decompression of the tibial nerve did not lead to good results in all cases. Therefore the indications for surgery should be handled with strong restriction.

Central Pain and Complex Motoric Symptoms after Gosarelin Therapy of Prostate Cancer

A 76-year-old man with prostate cancer T3N0M0 and increasing PSA was treated with goserelin three times in a half year. As soon as the first treatment, he described subjective muscle weakness. After the third treatment, he developed complex motoric symptoms and atypical central pain with a likely association to goserelin. His left arm had signs of spastic movement; pain deteriorated after relaxation. The right hand showed muscle cramps under passive movements of the left arm that were not typical for rigor. He felt aching and partial burning pain in his whole body. There were few allodynic areas, mainly in the left arm. Several treatment approaches failed and the patient died some weeks after the first contact with our pain clinic due to pneumonia.

Amyopathic dermatomyositis: Retrospective review of 37 cases

Criteria for diagnosis of amyopathic dermatomyositis vary, and the prognosis is not clear. Our purpose was to investigate prognosis regarding progression to myositis and associated malignancy. We reviewed the medical records of patients with dermatomyositis evaluated at our institution from 1976 to 1994. Of 746 patients with dermatomyositis, 37 (5%) with the amyopathic subtype were divided into 3 groups: group 1 (73%), no subjective or objective evidence of myopathy; group 2 (13%), no subjective muscle weakness but abnormalities detected by objective tests; group 3 (13%), subjective muscle weakness but no objective evidence of myopathy. Follow-up was conducted by means of a mailed questionnaire. For 25 patients, follow-up of 1 to 17 years after diagnosis showed muscle weakness in 2 patients in group 1 within 5 years after diagnosis. Five patients (13%) had associated malignancies. Of 7 (19%) patients with disease onset before the age of 18 years, none had progression to myopathy. Although it presents with cutaneous lesions indistinguishable from those of classic dermatomyositis, amyopathic dermatomyositis is a distinct entity. In most patients, amyopathic dermatomyositis does not progress to myopathy. Prognosis appears favorable, but malignancy may develop. (J Am Acad Dermatol 2002;46:560-5.)

Tizanidine. A review of its pharmacology, clinical efficacy and tolerability in the management of spasticity associated with cerebral and spinal disorders.

The central alpha 2 adrenoceptor agonist tizanidine is a myotonolytic agent used in the treatment of spasticity in patients with cerebral or spinal injury. Wide interpatient variability in the effective plasma concentrations of tizanidine means that the optimal dosage must be titrated over 2 to 4 weeks for each patient (dosages of 2 to 36 mg/day have been used in clinical trials). Maximum effects occur within 2 hours of administration. Antispastic efficacy has been demonstrated for tizanidine in placebo-controlled trials, with reduction in mean muscle tone scores of 21 to 37% versus 4 to 9% for patients receiving placebo. Improvement in muscle tone occurred in 60 to 82% of tizanidine recipients, compared with 60 to 65% of baclofen and 60 to 83% of diazepam recipients. Spasm frequency and clonus are also reduced by tizanidine. The most common adverse effects associated with tizanidine are dry mouth and somnolence/drowsiness. Muscle strength, as assessed by objective means, appears not to be adversely affected by tizanidine and subjective muscle weakness is reported less often by tizanidine recipients than by those receiving baclofen or diazepam. Global tolerability was assessed as good to excellent in 44 to 100% of patients receiving tizanidine, compared with 38 to 90% of baclofen and 20 to 54% of diazepam recipients. In conclusion, tizanidine is an antispastic agent with similar efficacy to that of baclofen and a more favourable tolerability profile. While drowsiness is a frequently reported adverse effect with both agents, subjective muscle weakness appears to be less of a problem with tizanidine than with baclofen. Tizanidine, therefore, appears to be an attractive therapeutic alternative for patients with spasticity associated with cerebral or spinal damage.

Clinical Effects of Intravenously Administered Dantrolene

To compare side effects after intravenous administration of dantrolene sodium in subjects susceptible to and those nonsusceptible to malignant hyperthermia (MHS and MHN, respectively). We studied two groups, six patients thought to be MHS and six assumed MHN subjects, and analyzed their responses to intravenously administered dantrolene. Dantrolene (3 mg/kg) was administered slowly into an antecubital vein, and blood samples were withdrawn from the other arm at 5 and 25 minutes after infusion. Shortly thereafter, all subjects underwent a clinical neurologic assessment, and side effects were graded subjectively by the study participants. Side effects occurred in all subjects. Visual symptoms occurred more commonly in MHN than in MHS subjects. Subjective muscle weakness of the extremities, dizziness, and fatigue occurred more commonly and were more severe in MHS patients than in MHN subjects. In patients recovering from an episode of malignant hyperthermia for which dantrolene has been administered, these side effects should be considered. Although the presence of side effects does not outweigh the usefulness of this drug in treating malignant hyperthermia, it may be a consideration in deciding whether to administer dantrolene prophylactically before surgical procedures in known or suspected MHS patients.

Action of dantrolene sodium in spasticity with low dependence on fusimotor drive

The effects of dantrolene sodium, an anti-spasticity drug with a site of action within the muscle fibres, were studied in 19 patients with spastic paresis. Oral doses were successively increased from 100 mg/day to a maximal tolerated level or up to 800 mg/day. Trial periods were 8–13 weeks. The responses of stretch reflexes to local cooling over the spastic muscles were used to differentiate α and γ spasticity. In the knee extensor and flexor muscle groups, cryo-negative α-spasticity was seen in 25 and cryo-positive γ-spasticity in 4 muscle groups. Ankle clonus was cryo-positive in 14 of 15 cases. Resistance to passive knee joint movements, ankle clonus and isometric or isokinetic muscle strength was determined quantitatively. The gait was recorded by intermittent-light photography and the muscle activation patterns in gait were studied in recordings of the average EMG from limb muscles. Functional disability and spasms were assessed from clinical examinations and interviews. Passive resistance at slow (6°/sec) and fast (30°/sec) knee joint movements decreased by 32% in the extensor muscles ( P = 0.005 resp. 0.001) and by 23–26% in the flexor muscles (not significant). Reduced passive resistance was observed in 16 of the muscles with γ-spasticity and in all 4 of the muscle groups with γ-spasticity. Clonus was diminished or abolished in 14 of 15 patients with this sign. Maximal isometric or isokinetic muscle strength was unaltered in the majority of the patients. In a few the strength was increased, in some it was decreased. The averaged EMG activity during walking as studied in 10 patients was increased in 35 of the 57 muscle groups examined. In some muscle groups, exaggerated activity attributable to spastic reflexes was reduced. Motor disability was decreased significantly in 10 patients. It was not significantly changed in 5 and deteriorated in 4 patients. Drowsiness and subjective muscle weakness were the most frequent side-effects. SGOT and SGPT were increased in 3 cases.

Myopathy in primary hyperparathyroidism. Observations in three patients.

Abstract In contrast to tne frequent occurrence of subjective muscle weakness and fatigue, objective muscle weakness and atrophy simulating polymyopathy have infrequently been reported in hyperpara...