A case of polymyositis complicated with myasthenic crisis

We report a 62-year-old woman who suffered from polymyositis (PM) complicated with myasthenic crisis. Electromyography and muscle biopsy indicated a diagnosis of PM; however, respiratory failure due to respiratory muscle weakness was seen in spite of a normal serum creatine kinase (CK) level. The positive anti-acetylcholine receptor antibody led us to the diagnosis of myasthenic crisis. PM with respiratory muscle weakness is rare. We suggest that the possibility of other neurological disorder complications should be considered when PM patients have respiratory muscle weakness out of proportion to the serum CK level.     

From profound hypokalemia to life-threatening hyperkalemia: a case of barium sulfide poisoning

We describe a 25-year-old man who was brought to the emergency department with skeletal muscle weakness, respiratory arrest, and rhabdomyolysis, as well as life-threatening hyperkalemia, after ingesting a depilatory containing barium sulfide (Magic Shave; Carson Products Co, Savannah, Ga). The findings of his physical examination were significant for hyporeflexia with marked weakness. He was in respiratory distress and required intubation and ventilatory support owing to progressive weakness of the respiratory muscles. His serum potassium level was 1.5 mmol/L. He was treated with intravenous and oral potassium. His serum potassium level peaked at 8.3 mmol/L and his serum creatine kinase level at 8286 IU/L. His acute respiratory weakness resolved with correction of the potassium concentration; his rhabdomyolysis responded well to hydration; and his renal function returned to normal. We also discuss the various pathophysiological findings in this case and compare our patient with another who, despite ingesting a similar amount of the same hair remover, did not develop any of the above complications.     

老年呼吸衰竭患者血清心肌酶的观察分析

目的观察血清心肌酶在老年呼吸衰竭患者中的变化。方法应用自动生化分析仪测定血清心肌酶、血气分析。结果呼吸衰竭组AST平均值为47.4IU/L,LDH平均值为269.8IU/L,CK平均值为178.6IU/L,CK-MB平均值为11.6IU/L;对照组AST平均值为29.2IU/L,LDH平均值为192.5IU/L,CK平均值为135.6IU/L,CK-MB平均值为6.7IU/L。两组比较,呼衰组血清心肌酶活力升高,明显高于对照组,两组比较有显著差别(P<0.01)。结论老年呼吸衰竭时血清心肌酶升高对老年呼吸衰竭患者病情严重程度和心肌受损程度以及疗效观察有一定的临床意义。     

Respiratory muscle involvement in multiple sclerosis.

Respiratory complications are common in the terminal stages of multiple sclerosis and contribute to mortality in these patients. When respiratory motor pathways are involved, respiratory muscle weakness frequently occurs. Although it is well established that weakness of the respiratory muscles produces a restrictive ventilatory defect, the degree of muscle weakness and pulmonary function are poorly related. Respiratory muscle weakness was observed in patients with normal or near normal pulmonary function. Expiratory muscle weakness is more prominent than inspiratory muscle weakness and may impair performance of coughing. Subsequently, in addition to bulbar dysfunction, respiratory muscle weakness may contribute to ineffective coughing, pneumonia, and sometimes even acute ventilatory failure may ensue. Respiratory muscle weakness may also occur early in the course of the disease. Recent studies suggest that the respiratory muscles can be trained for both strength and endurance in multiple sclerosis patients. Whether respiratory muscle training delays the development of respiratory dysfunction and subsequently improves exercise capacity and cough efficacy, prevents pulmonary complications or prolongs survival in the long-term remains to be determined.     

Asymptomatic sporadic dysferlinopathy presenting with elevation of serum creatine kinase. Typical distribution of muscle involvement shown by MRI but not by CT

We report an 18-year-old man with elevation of the creatine kinase (CK) level to 11,068 IU/L. There was no muscle atrophy or fat replacement on CT while muscles in the posterior compartment of lower legs showed high T2 signal intensity on MRI. We performed muscle biopsy from the gastrocnemius muscle. Immunohistochemical analysis demonstrated an absence of dysferlin leading to a diagnosis of preclinical dysferlinopathy. Typical distribution of muscle involvement was demonstrated not by CT but by MRI which may have contributed to facilitating diagnosing the earliest stage of preclinical dysferlinopathy, presenting with asymptomatic elevation of serum creatine kinase.     

Visual Hallucinations in a Patient with Adult Onset Acid Maltase Deficiency Disorder

A 66-year-old male presented with visual hallucinations. He had chronically elevated serum creatine kinase (CK) levels without muscle weakness. His hospital course was complicated by hypercapnic respiratory failure requiring mechanical ventilation. His hallucinations completely subsided on mechanical ventilation. Elevated CK levels prompted a muscle biopsy, which showed myopathy consistent with acid maltase deficiency disorder (AMDD). This is the first reported case of adult onset AMDD presenting with psychiatric symptoms. Our objective in reporting this case is to encourage early recognition of neuromuscular respiratory failure in AMDD and to reinforce that respiratory failure may develop without associated extremity muscle weakness.     

A Japanese Patient with Hereditary Myopathy with Early Respiratory Failure Due to the p.P31732L Mutation of Titin

Hereditary myopathy with early respiratory failure (HMERF) is caused by titin A-band mutations in exon 344 and is considered quite rare. Respiratory insufficiency can be the sole symptom in the disease course. We herein report the first Japanese HMERF patient with a p.P31732L mutation in titin. The patient manifested respiratory failure and mild weakness of the neck flexor muscle at 69 years old and showed fatty replacement of the bilateral semitendinosus muscles on muscle imaging. Our case indicates that HMERF with a heterozygous p.P31732L mutation should be included in the differential diagnosis of muscular diseases presenting with early respiratory failure.     

Spontaneous remission of dermatomyositis which developed one month after normal delivery]

A case of dermatomyositis which developed one month after normal delivery and subsided spontaneously was reported. A 29-year-old woman gave birth to a healthy child. One month later, she noticed muscular pain and weakness of the upper extremities. On admission, there were diffuse edema of upper eyelids with heliotrope rash. The reddish skin rashes were observed on the extensor surfaces of the PIP and MP joints of fingers. Erythrocyte sedimentation rate was 29 mm/hr. The lactic dehydrogenase (LDH), SGOT, CK levels were 470 (normal 150 to 320 IU/l), 43 (normal 6 to 25 IU/l) and 317 (normal 21 to 110 IU/l) respectively. Autoantibodies to nuclear and cytoplasmic antigens were negative. Rheumatoid factor and anti-DNA antibody were negative. Thyroid function was normal. An electromyogram (EMG) demonstrated small amplitude short-duration polyphasic motor unit potentials. The muscle biopsy specimen from left upper arm showed degenerating muscle fibers and infiltration of inflammatory cells surrounding blood vessels. The skin biopsy revealed the presence of edema and perivascular infiltration of lymphocytes. Based on these clinical features and results of various diagnostic tests, a diagnosis of dermatomyositis was established. After the admission, muscle strength has improved dramatically and the CK returned to normal level without specific drug therapy. She has since been seen as an out patient, and complete remission lasted for two years up to date. Review of the literature disclosed that 13 cases of PM/DM which developed during pregnancy or postpartum have been reported including the present case. Detailed analysis showed that these patients were characterized by mild muscular diseases, rare occurrence of internal organ involvements and good response to steroid therapy. As our case, a spontaneous remission was also observed. Although the mechanism involved in occurrence of inflammatory myositis associated with pregnancy or delivery are not clarified, these patient indicated a presence of subset of PM/DM which do not require intensive drug therapy.     

Statin-induced necrotizing autoimmune myopathy: An uncommon complication of a commonly used medication

A well-known side effect of statin therapy is myopathy. We report a case of statin induced necrotizing autoimmune myopathy, a rare variant of statin-induced myopathy. A 64-year-old gentleman on atorvastatin presented with muscle weakness. Initial laboratory results showed elevated liver function tests, a creatine phosphokinase (CPK) of 8200 IU/L, and positive urine myoglobin. Despite discontinuing atorvastatin, his CPK remained persistently elevated. Muscle biopsy was consistent with necrotizing myopathy. Anti-HMG CoA reductase antibody was strongly positive. Steroids followed by intravenous immunoglobulin were given. The patient’s muscle weakness, CPK, and liver functions gradually improved, and he was eventually discharged on oral steroids. Statin induced necrotizing autoimmune myopathy should be considered when discontinuing statin does not lead to muscle recovery and improvement in CPK. Diagnosis is confirmed by positive anti-HMG-CoA reductase autoantibody.     

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.     

Normocalcemic Primary Hyperparathyroidism Presenting with Muscle Weakness and Body Pain

We herein report a 39-year-old woman who had aggravated body pain, waddling gait, and fatigability for the past 2 years. A neurological examination showed hyperreflexia and proximal muscle weakness. The serum calcium level was normal (10.1 mg/dL). However, serum alkaline phosphatase (3,855 IU/I) and parathyroid hormone (1,008 pg/mL) levels were remarkably high. Cervical ultrasonography revealed parathyroid goiter. The patient was diagnosed with hyperparathyroidism. Her muscle weakness and pain improved within three months after parathyroidectomy. Our findings suggest that clinicians should consider hyperparathyroidism as a differential diagnosis in patients with proximal muscle weakness, even if the serum calcium level is normal.     

Respiratory muscle weakness and ventilatory failure in AL amyloidosis with muscular pseudohypertrophy

Generalized muscle weakness culminating in ventilatory failure developed in a 59-year-old man with kappa light chain multiple myeloma. Physical examination demonstrated skeletal muscle enlargement, severe proximal muscle weakness, and macroglossia, consistent with amyloid-associated muscle pseudohypertrophy. Pulmonary function studies revealed a severe restrictive abnormality with a low maximal inspiratory pressure and maximal voluntary ventilation. Arterial blood gas values and chest radiographic results were normal. There was no clinical evidence of cardiac or central nervous system disease. At autopsy, skeletal muscles and diaphragm were diffusely infiltrated by amyloid. There was also multifocal deposition of amyloid in alveolar septae, esophagus, and subendocardium. This report suggests that ventilatory failure may occur as a complication of myeloma-associated (AL) amyloidosis involving the respiratory muscles.     

A case of microscopic polyangiitis with severe cardiac and respiratory muscle involvement]

A 66-year-old female was admitted to our hospital in January, 1998, complaining of low grade fever and muscle weakness of her legs. Physical examination revealed muscle weakness of her neck (4/5) and proximal skeletal muscles of her bilateral legs (3/5-4/5). She showed proteinuria and microhematuria. Her serum levels of ureanitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, creatinekinase, aldolase and myoglobin were all within the normal ranges. Antinuclear antibodies were negative, but her serum levels of pANCA (743 EU) and C reactive protein (18.0 mg/dl) were elevated. Neuroconduction velocity of her left common peroneal nerve was decreased to 40.8 m/sec and electric myograph showed neurogenic changes. Magnetic resonance images (MRI) of her bilateral thigh depicted high signal intensity in quadriceps by T 2 weighed images, but the signals were not enhanced by gadolinium injection. Muscle and renal biopsies revealed necrotizing vasculitis of the small arteries. Crescentic glomerulonephritis was also observed by renal biopsy. These findings supported the diagnosis of microscopic PN. On 16 th admission day, she developed acute cardiac and respiratory failures due to cardiac and respiratory muscle involvements with PN, and was assisted by mechanical ventilation. She was treated with methylprednisolone pulse therapy (500 mg/day, three consecutive days) on 18 th admission day, followed by 40 mg of oral prednisolone daily. However, her symptoms deteriorated, and herserum creatinine levels increased to 2.4 mg/dl. On 24 th admission day, intravenous cyclophosphamide pulse therapy (500 mg/day) was instituted. Her cardiac wall motion on echocardiography and serum creatinine levels gradually improved, but her skeletal and respiratory muscle weakness did not improve. On 38 th admission day, she was complicated with respiratory infection by methicillin resistant Staphylococcus aures. On 62 th admission day, she died of endotoxic shock. This is the first report describing respiratory muscle involvement with PN, and the second report describing MRI findings of muscle involvement by PN. Therefore, our case provides important clinical information for the diagnosis and treatment of the disease.     

Reversible respiratory muscle weakness in hypothyroidism

Physiological studies performed 1 week after initiation of thyroid replacement showed persistence of significant respiratory muscle weakness in a patient presenting with hypothyroidism and hypercapnia. Repeat studies 12 months later demonstrated return of respiratory muscle strength to normal. Earlier reports on respiratory failure in hypothyroidism had postulated a critical role for respiratory muscle weakness in the genesis of hypercapnia. Since hypercapnia was rapidly reversed despite the persistence of severe respiratory muscle weakness, this explanation may not be always correct. It appears than in our patient thyroid replacement had its primary effect on the respiratory control system.     

Pattern of breathing in a case of generalized respiratory muscle weakness

A patient with motor neuron disease is described. He had signs and laboratory data indicating generalized, symmetrical weakness, involving both inspiratory and expiratory muscle groups. The pattern of breathing involving recruitment of accessory muscles and expiratory contraction of abdominal muscles is similar to that seen in normal people at high minute ventilation, and suggests the compensating mechanism for increasing motor discharge to weak respiratory muscles is mediated centrally. Observation of this sort of respiratory activity gives a clinical clue to generalized respiratory muscle weakness.     

TREATMENT OF MYASTHENIA GRAVIS WITH PREDNISONE

Eight patients with severe generalised myasthenia gravis and one with ocular myasthenia gravis have been treated with prednisone for between 6 and 25 months. Strength returned to normal or almost normal in the limb and trunk muscles of seven of the eight patients with generalised weakness and improved slightly in the limb and trunk muscles, with greater improvement in the respiratory muscles, of the other patient. Strength decreased during the early phase of treatment in two patients who later showed great improvement, but in one of them ocular and pharyngeal weakness have persisted and one has had relapses. The patient with purely ocular signs lost them. Prednisone was given on alternate days, but it may be advisable to give it more frequently at the start of treatment.     

Incidence of cocaine-associated rhabdomyolysis

STUDY HYPOTHESIS: Rhabdomyolysis is a common complication of cocaine use, and muscle symptoms fail to predict its development. STUDY POPULATION: A prospective, convenience sample of patients presenting to the emergency department of a large inner-city hospital with complaints related to cocaine use were eligible for inclusion. Patients were excluded if they had other potential causes of elevated creatine kinase (CK) levels or rhabdomyolysis. A control group comprised patients who were not cocaine users and satisfied the exclusion criteria. Sixty-eight patients were studied. METHODS: Initial evaluation included determination of the presence of muscle pain or swelling and total CK levels. Patients with a CK level of more than 800 U/L had additional tests, including a urine myoglobin, urine drug screen, and serum phosphorus. Rhabdomyolysis was defined by a serum CK level of more than 1,000 U/L (more than fivefold that of normal). CK levels were compared by two-tailed Student's t test. Muscle symptoms were compared with the development of rhabdomyolysis by Fisher's exact test. RESULTS: The CK level in the cocaine group was 931 +/- 1,785 U/L (mean +/- 1 SD). The CK level in the control group was 242 +/- 168 U/L (P = .028). Of the cocaine users, 24% (eight of 34) had rhabdomyolysis; one developed multiorgan failure and died. No patient in the control group had a CK level of more than 1,000 U/L. Only one cocaine user who developed rhabdomyolysis had muscle symptoms. Three cocaine users had muscle symptoms but did not develop rhabdomyolysis. No patient in the control group had muscle symptoms or developed rhabdomyolysis. Muscle symptoms did not predict the CK level (P = .55). CONCLUSION: This study revealed that 24% of the cocaine users had rhabdomyolysis. Many of the cases of rhabdomyolysis were not predictable from history or physical examination, making laboratory evaluation essential.     

Severe respiratory failure secondary to Cushing's myopathy.

We report a 55-year-old woman with typical clinical, biochemical and radiological features of Cushing's disease, who developed a severe respiratory insufficiency as the main symptom. She also complained of proximal muscle weakness over the last year and progressive dyspnea over the last four months. Bronchospasm, respiratory infection or cardiologic dysfunction were excluded. Arterial blood gas analysis showed severe respiratory insufficiency with hypoxemia and hypercapnia, respiratory acidosis and a normal alveolar-arterial oxygen gradient. Spirometry and plethysmography showed a restrictive ventilatory failure and maximum inspiratory and expiratory pressures were reduced. These findings were strongly suggestive of neuromuscular disease. Serum creatine kinase, aldolase, sodium, potassium and thyroid function tests were normal. An electromyogram and a muscle biopsy confirmed myopathic disease. Ketoconazole therapy improved her symptoms and respiratory function tests. In conclusion although proximal myopathy is a frequent presenting symptom of Cushing's syndrome, involvement of respiratory muscles with severe restrictive ventilatory dysfunction has not been previously reported as the main initial feature of Cushing's disease. Medical treatment of hypercortisolism improves muscle strength and resolves the respiratory insufficiency.     

Diaphragm paralysis causing ventilatory failure in an adult with the rigid spine syndrome

A syndrome consisting of a rigid spine and myopathy predominantly affecting proximal limb muscles has been previously described in children, and as with most neuromuscular disorders, the respiratory muscles appear to be affected only at an advanced stage in the disease. We describe an adult male with this syndrome who presented with ventilatory failure caused by severe respiratory muscle weakness and who demonstrated profound nocturnal arterial oxygen desaturation, particularly during rapid eye movement sleep. Treatment with negative pressure ventilation initially resulted in only modest improvements in symptoms, blood gas tensions, and nocturnal desaturation. The cause of this only partial improvement was upper airway obstruction provoked by the mode of ventilatory support used. After tracheostomy there was a dramatic and sustained improvement in symptoms and blood gas tensions and complete abolition of nocturnal arterial oxygen desaturation. This is the first report of an adult with the rigid spine syndrome presenting with ventilatory failure and cor pulmonale due to severe respiratory muscle weakness.