Changes in the cytoskeletal proteins, sarcoplasmic reticulum, and capillaries in acute relaxant-steroid myopathy (ARSM) in contrast to the corticosteroid myopathy

Since we reported a case of acute relaxant-steroid myopathy (ARSM) in 1994, we continued histological studies and compared the findings with those in a case of corticosteroid myopathy (CM). It was revealed that (1) dystrophin, spectrin, beta dystroglycan, and sarcoglycans on the cell surface were decreased, (2) regular arrangement of the sarcoplasmic reticulum was lost, and (3) some capillaries were degenerated. Since none of these changes were seen in CM, it became clear that ARSM is different from CM. It was estimated that continuous administration of non-depolarizing muscle relaxant produces a state akin to denervation. Combination of denervation, immobilization and circulatory disturbance in ARSM not only augments the effects of corticosteroids, but they produce changes different from CM, namely impairment of the cell membrane system (both internal and external) and capillary degeneration. Received: 7 January 1998 / Revised: 12 August 1998, 14 October 1998 / Accepted 21 October 1998     

Central nervous system and muscle involvement in dengue patients: A study from a tertiary care center

BackgroundNeurological involvement in dengue virus (DENV) infection is being increasingly reported. There is paucity of studies evaluating the relative frequency of central nervous system (CNS) and muscle involvement in dengue.ObjectivesTo evaluate the frequency and prognosis of neurological and muscle involvement in dengue, and correlate these with dengue subtypes.Study designConsecutive dengue patients were included, and their clinical features, laboratory investigations and cerebrospinal fluid (CSF) findings were recorded. Cranial MRI was done in unconscious patients and electromyography and nerve conduction study in patients with flaccid weakness. Patients were categorized into encephalopathy, encephalitis, immune mediated and dengue associated muscle dysfunction (DAMD). Outcome at 1 month and its predictors were evaluated.Results116 patients aged 5–70 years were included; 82 had dengue fever (DF), 18 had dengue hemorrhagic fever (DHF), and 16 had dengue shock syndrome (DSS). Neurological manifestations were present in 92 (79%); encephalopathy in 17 (15%), encephalitis in 22 (19%), transverse myelitis in 1 (1%) and DAMD in 52 (45%) patients. Central nervous system (CNS) involvement was commoner in DHF/DSS compared to DF (44% vs 26%). 10 patients with CNS involvement died versus 1 with DAMD. The patients in the CNS group had more frequent hypotension, renal dysfunction and respiratory failure compared to the DAMD group, and had worse outcome. DENV2 and DENV3 were the commonest serotypes, but serotypes did not differ between CNS and DAMD groups.ConclusionsDAMD is commoner than CNS involvement in dengue. CNS involvement however, is associated with more serious illness and predicts poorer outcome.     

An Approach to Myopathy for the Primary Care Clinician

Patients with muscle weakness are frequently encountered in the primary care clinic; however, the identification of an underlying disorder of muscle can pose a significant challenge. The aim of this review article is to provide a clinical and diagnostic framework to aid the primary care clinician in the detection and evaluation of suspected myopathies.     

Myopathy with MTCYB mutation mimicking Multiple Acyl-CoA Dehydrogenase Deficiency

We describe two patients with mitochondrial DNA mutations in the gene encoding cytochrome b (m.15579A>G, p.Tyr278Cys and m.15045G>A p.Arg100Gln), which presented as a pure myopathic form (exercise intolerance), with an onset in childhood. Diagnosis was delayed, because acylcarnitine profile showed an increase in medium and long-chain acylcarnitines, suggestive of multiple acyl-CoA dehydrogenase deficiency, riboflavin transporter deficiency or FAD metabolism disorder. Implication of cytochrome b in fatty acid oxidation, and physiopathology of the mutations are discussed.     

Recent Advances In the Pathology of Alcoholic Myopathy

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Victor R. Preedy and Junko Adachi. The presentations were (1) Alcoholic myopathy: Past, present and future, by Timothy J. Peters and Victor R. Preedy; (2) Protein adducts in the type I and II fiber-predominant muscles of the ethanol-fed rat, by Simon Worrall, Seppo Parkkila, and Onni Niemela; (3) Hydroperoxides and changes in alcoholic myopathy, by Junko Adachi, Migiwa Asamo, and Yasuhino Ueno; and (4) A close association between testicular atrophy, muscle atrophy, and the increase in protein catabolism after chronic ethanol administration, by Kunihiko Takeda, Masayoshi Yamauchi, Kazuhiko Sakamoto, Masaru Takagi, Hisato Nakajima, and Gotaro Toda.     

脂质沉积性肌病的临床与病理分析

目的探讨脂质沉积性肌病(lipidstoragemyopathy,LSM)的临床表现及病理学特点。方法回顾分析7例LSM的临床表现、肌电图及肌肉活检病理改变。结果LSM的主要临床特点为亚急性或慢性起病,近端肌无力,症状呈波动性,血清肌酶有不同程度的升高,多数病人肌电图示肌源性损害,激素治疗有效。病理学特点为肌纤维内可见大量均匀的小筛孔样空泡,部分空泡融合成大泡或形成裂隙状。ORO染色证实筛孔样空泡为大量红染的脂肪颗粒充填,部分肌纤维破裂,伴脂肪颗粒堆积。受累纤维以Ⅰ型纤维为主。电镜证实肌纤维内脂滴堆积,其中1例伴有异常线粒体增多。结论LSM是一种以易疲劳和肌无力为主要临床表现的脂质代谢障碍性肌病,激素治疗可获得良好疗效。肌肉活检病理学检查是诊断LSM的重要手段。     

Freeze-fracture studies of muscle plasma membranes in myopathic patients with hypo-and hyperthyroidism

To examine the influence of thyroid hormone on the skeletal muscle plasma membrane, we analyzed the changes in ultrastructural architecture and membrane area complexed with digitonin of muscle plasma membrane in myopathic patients with hypo-and hyperthyroidism by the conventional freeze-fracture (F-F) technique and F-F cytochemistry using the sterol-specific ligand digitonin. The densities of flask-shaped invaginations, which are mainly thought to correspond to caveolae, intramembranous particles, and orthogonal arrays, and the changes of digitoninreacted membrane areas in the muscle plasma membranes in three patients with hypothyroid myopathy and one patient with both myasthenia gravis and hyperthyroidism were compared with those in age-matched controls. In the conventional F-F study, the muscle plasma membrane of hypothyroid patients showed increased invagination density, whereas that of the hyperthyroid patient was normal ultrastructurally. In the F-F cytochemistry study, however, the ratio of digitonin-reacted membrane areas versus fractured membrane areas was not different between hypothyroid patients and controls, whereas that of the hyperthyroid patient was lowered in comparison with that of control. These results suggest that thyroid hormone may alter the biochemical properties and ultrastructural architecture of muscle plasma membrane.This study was presented at the 29th annual meeting of the Clinical Electron Microscopy Society of Japan, Sapporo, October 2–3, 1997     

以肌损害为主要表现的原发性甲状腺功能减退症五例

目的提高对重症原发性甲状腺功能减退症伴随肌病患者临床特征、病变特点及其治疗的认识。方法回顾性分析1996年3月至2003年11月收治的5例重症原发性甲状腺功能减退伴肌损害患者的临床资料及治疗转归,并结合相关文献对该病的临床特点进行分析。结果5例患者突出的临床表现为对称性近端肌无力、气短、胸痛、呼吸及吞咽困难。血肌酸激酶均显著增高(2 885~10 450 U/L)。结论应将伴有肌损害的原发性甲状腺功能减退症患者与多发性肌炎鉴别,及时给予甲状腺激素替代治疗对甲状腺功能减退相关性肌病有较好疗效。     

Bariatric surgery related proximal myopathy: A partially reversible complication

Deficiency neuropathies and rhabdomyolysis have previously been reported after bariatric surgery (BS) but never myopathies. We report cases of five patients with morbid obesity who developed within 2 to 4 months of a BS, proximal myopathy following significant and rapid weight loss worsened by postoperative gastrointestinal complications. Muscle weakness concerned lower limbs in particular in quadriceps and less frequently in upper limbs and diaphragm, sometimes mimicked a Guillain–Barré syndrome. Muscle biopsy performed in 1 patient, revealed selective atrophy of type 2 fibers. Weakness slowly decreased with refeeding with vitamins supplementation. We enlarge here the clinical pattern of post-BS complications.