Two children seriously weakened by myasthenia

Two boys, aged 2 and 11 years, presented with fever and muscle weakness that resulted in respiratory insufficiency. A physical examination and additional tests confirmed the diagnosis 'myasthenia'. Acetyl cholinesterase-inhibitor therapy had a favourable effect. Myasthenia is a diagnosis that should be considered for every child presenting with muscle weakness of unknown origin.     

The influence of the helmet respirator on peak flow rate in aluminum potroom

The efficiency of the Racal Airstream helmet respirator in improving peak expiratory flow rates (PEFR) and symptoms (dyspnea, wheezing, and cough) in aluminum potroom workers with respiratory complaints was assessed in 19 workers. Peak expiratory flow readings and symptom recording from a 2-week working period with use of the respirator were compared with a period when the 3M 9906 disposable mask was used. The study was designed as a randomized, parallel, cross-over study with five or six daily measurements of PEFR and daily symptom recording. A significant number of workers (15) had a higher mean peak flow in the helmet period than in the nonhelmet period (p less than 0.01); symptoms did not improve significantly in the helmet period. Objective evidence of respiratory protection was observed for the group of workers as a whole, but the effect on symptoms as well as individual effect on peak flow was minor in the majority of the workers.     

Emergencies in neuromuscular pathology

Acute muscle weakness (AMW) is the predominant symptom of neuromuscular emergencies, especially if it affects the respiratory or oropharyngeal musculature . AMW is a multi-etiological syndrome, with different lesion levels in the motor unit. Within the broad group of neuromuscular diseases, those that most frequently provoke AMW and respiratory failure are Guillain-Barré syndrome (GBS) and myasthenia gravis (MG). GBS is the most frequent cause of acute flaccid paralysis; it can cause respiratory failure in a third of cases, making mechanical ventilation necessary. Accurate diagnosis of this syndrome enables immunomodulatory treatment to be started, which has been shown to modify the course of the disease. Besides, clinical evaluation of the patients and knowledge of the simple tests of neurophysiology and respiratory function will guide the decision on mechanical ventilation, avoiding emergency intubation. The most frequent emergency caused by MG is myasthenic crisis, defined by the deterioration in the bulbar function with acute respiratory insufficiency and risk of respiratory stoppage. This occurs in 15-20% of myasthenic patients and can be triggered by numerous factors. Besides early identification of the crisis, it is important to suppress the triggering factors and to provide measure of ventilatory support. Amongst the pharmacological measures, the most useful instruments at present are plasmapheresis and intravenous immunoglobulins; these treatments do not cancel the need for intensive vigilance and of checking for imminent signs of respiratory failure that will involve invasive or non-invasive ventilatory support.     

Four family members with proximal myotonic myopathy

A 41-year-old woman had a 15-year history of pain in her thighs and arms, which also became weaker, and a decrease in visual acuity. Her 35-year-old brother, their 38-year-old sister and their 64-year-old mother also had myalgia, myotonia and proximal muscle weakness, and the women also had cataracts. Additional examinations and tests led to a diagnosis of proximal myotonic myopathy (PROMM) in all four cases. Neurological and ophthalmological follow-up was provided on a yearly basis, including ECG. The clinical features of PROMM display similarities to the adult form of myotonic dystrophy (MD) but differ in the proximal localisation of the muscle weakness and the frequent occurrence of pain in the affected muscles. PROMM is an autosomal dominant hereditary multisystemic disorder with a less serious course than MD and is rarely accompanied by cognitive disorders. In most cases, a genetic defect on chromosome 3q21 is the cause of the disease. A probable diagnosis can be made on the basis of the clinical symptoms and the results of simple laboratory tests, and can be confirmed via DNA analysis. As yet, the disorder can only be treated symptomatically, preferably via a multidisciplinary approach by a neurologist, an ophthalmologist, a cardiologist and a rehabilitation specialist.     

Longitudinal Analysis of Quadriceps Muscle Strength in Patients with Previous COVID-19 Hospitalization and in Patients with Post-Acute Sequelae following Mild COVID-19

Muscle weakness is a prominent symptom in post-acute sequelae of COVID-19 (PASC). However, few studies have objectively and longitudinally assessed muscle strength after varying COVID-19 severity grades. This observational study aimed to explore the prevalence, determinants, and 1.5 years change of quadriceps muscle weakness in 98 patients discharged from COVID-19 hospitalization and in 50 patients with PASC following mild COVID-19. Isometric quadriceps maximal voluntary contraction (MVC) was assessed on a computerized dynamometer at three visits. Also, in a subgroup of 14 post-COVID-19 patients with quadriceps muscle weakness, muscle thickness and echo intensity were determined by muscle ultrasound of nine upper and lower extremity muscles. Muscle weakness was found in 59% of post-hospitalized patients and in 65% of those with PASC following mild COVID-19 at ~14 weeks after acute COVID-19. Whereas during ~1.5 years follow-up MVC modestly improved, muscle weakness prevalence remained unchanged. Hospital length of stay and diabetes mellitus were identified as possible predictors of muscle weakness following COVID-19 hospitalization. No predictors could be identified in those with PASC following mild COVID-19. Ultrasound outcomes revealed no large structural abnormalities. In conclusion, clinically relevant muscle weakness is common after COVID-19 and its long-term improvement is poor. Future studies with relevant control groups are warranted to confirm our data.     

Myopathy associated with respiratory insufficiency: diagnostic difficulties in adult-onset Pompe disease

INTRODUCTION: Adult-onset acid maltase deficiency myopathy is a rare lysosomal storage disease with an autosomal recessive pattern of inheritance. The disease can be manifested with respiratory insufficiency and fatigue. METHODS: A case of a 45-year-old male patient is presented, and difficulty in diagnosis is discussed. RESULTS: The patient had been repeatedly examined because of hypersomnia, dyspnea and fatigue for a full year before a neurological consultation was requested. Artificial ventilation resulted in a dramatic improvement of his symptoms. Neurological examination revealed myopathy. Electrophysiological myotonia and glycogen storage in muscle biopsy specimen suggested acid maltase deficiency. The diagnosis was established by genetic testing detecting the previously described homozygous c.-45T > G mutation in the alpha-glucosidase gene. DISCUSSION: Rare hereditary neurological diseases can be also suspected as cause of chronic unexplained respiratory insufficiency resulted in hypersomnia and fatigue due to hypercapnia and myopathy. A proper diagnosis can contribute to early diagnosis and introduction of enzyme replacement therapy may reduce or stop clinical progression. Genetic diagnosis can also provide a possibility for prenatal testing.     

Respiratory function during oxygen administration in chronic obstructive pulmonary disease

Patient with severe chronic obstructive pulmonary disease (COPD) can develop respiratory muscle weakness and fatigue. Arterial hypoxemia can predispose to this condition. To assess whether O2 administration improved respiratory muscle function and respiratory pattern in COPD 11 patients with chronic hypoxemia were examined. Each patient was first submitted to respiratory function studies, including lung volumes, in normal and recumbent position, respiratory frequency, Ti/Te, Ti/Tot, maximal inspiratory and expiratory pressures (Pimax, Pemax) and arterial gas analysis breathing room air. All these tests were repeated during oxygen Administration through a nasal cannula. The arterial PO2 improved from 50 +/- 7 mmHg to 81 +/- 28 mmHg but the breathing pattern, Pimax and Pemax as well as lung volumes remained unchanged. It is concluded that oxygen, in short term administration, doesn't influence respiratory pattern and muscle function.     

Inclusion body myositis pathomechanism and therapy

Inclusion body myositis is an acquired inflammatory muscle disease belonging to the family of idiopathic inflammatory myopathy with vacuola formation. Approximately 15-28% of idiopathic inflammatory myopathy patients suffer from inclusion body myositis. Early diagnosis is very important due to the slowly progressive disease course and consecutive muscle atrophy. Inclusion body myositis is the most common chronic progressive muscle disease over the age of 50 years. Both degenerative processes including beta-amyloid accumulation and inflammatory processes, such as CD8 positive T-lymphocytes mediated cellular citotoxicity take part in the pathomechanism of the inclusion body myositis. These findings are well demonstrated by the parallel presence of vacuolized muscle fibers rarely invaded by T cells and intact muscle fibers invaded by inflammatory T-cells in biopsy specimens. MHC-I/CD8 komplex was introduced into the newly revised diagnostic criteria as a specific immune marker which helps to differentiate inclusion body myositis from aspecific inflammation present in other muscle dystrophies. Clinically both proximal and distal muscle weakness, respiratory muscle weakness and dysphagia are present. Interstitial lung disease is infrequent. Inclusion body myositis responds poorly to antiinflammatory treatment due to the predominant degenerative processes and it often results in only biochemical response instead of clinical. Diagnosis and differential diagnosis of inclusion body myositis are a very special challenge for the physician due to the diagnostic procedures which need immunhistochemical background. New therapeutic targets, monoclonal antibodies against the costimulatory molecules, anticitokine therapy may provide further improvement in the quality of life of inclusion body myositis patients.     

An atypical case of neuralgic amyotrophy with respiratory muscle weakness: case report and review of literature

This report is of an atypical case of neuralgic amyotrophy with a Horner's syndrome, bilateral brachial plexus, lumbar plexus and phrenic nerve involvement. The diagnosis isconfirmed based on a classical history and examination findings with typical neurophysiological investigations for this condition. This report also highlights the novel use of positional magnetic resonance imaging to investigate patients with respiratory muscle weakness. This case report expands the recognised clinical features of neuralgicamyotrophy and the literature concerning atypical features of this condition is reviewed.     

From gene to disease; the dystrophin gene involved in Duchenne and Becker muscular dystrophy

Duchenne and Becker muscular dystrophy (DMD and BMD) are progressive disorders, which almost exclusively affect males. DMD is the more severe type with an onset at 2-3 years of age. Patients become wheelchair-bound before the age of 13 and often die due to cardiac arrest or respiratory insufficiency. BMD, a more varying phenotype which may overlap with limb girdle muscular dystrophy (LGMD), has a less severe muscle weakness which starts later than in DMD patients. DMD carriers may show some muscle weakness. The dystrophin gene (2.4 Mb), known to be involved in DMD/BMD, codes for a 427 kilodalton muscle-specific protein named dystrophin as well as several tissue-specific isoforms. Dystrophin, as part of a membrane-bound complex of proteins, connects the cytoskeleton of the muscle cell to the extracellular matrix. Since 1985, when highly reliable carrier detection and prenatal diagnosis at the DNA level became possible, over 250 prenatal tests have been performed. Molecular genetic analysis, highlighted a phenomenon called germinal mosaicism, which explains the recurrence of de novo mutations and led to the discovery of the so-called reading-frame rule, which helps to discriminate between DMD and BMD. Fifteen years after the discovery of the dystrophin gene, mutations can be detected in 95% of the patients, while the remaining 5% are still hiding within this very large gene.     

The symptomatic treatment of amyotrophic lateral sclerosis

Patients with amyotrophic lateral sclerosis (ALS) have symptoms of progressive muscle weakness, of disturbed speech and swallowing, and in the terminal phase those of respiratory weakness. Treatment options, in particular those for excessive weight loss and respiratory weakness, should be introduced to the patients and their families when the patient is emotionally capable and before dysarthria severely hampers communication. Special equipment for keeping the patient as mobile as possible should be made available much earlier than in the case of other diseases of the muscles as in ALS progression is much faster. Cramps, pathological crying or laughter, spasms, and spasticity can all be treated by medication. When speech can no longer be understood, adaptive strategies such as sign language, mime, posture and communication apparatus varying from a note pad to advanced computer systems can be used. Sialorrhoea, caused by difficulty swallowing with its accompanying danger of aspiration can be halted by the use of medication, by radiotherapy and by the injection into the salivary glands of botulin A toxin. Weight loss, also a result of dysphagia, can be avoided by eating frequent small meals or if necessary performing a percutaneous endoscopic or radiological gastroscopy. Excess mucus in the respiratory tract can be treated with anticholinergics. Difficulty in coughing up thick and sticky mucus cannot always be adequately helped. Respiratory weakness is treatable by external respiratory supportive therapy using a nasal mask, as well as invasive respiratory support via a trachcostoma and by treating the symptoms of respiratory weakness. The latter form of treatment is palliative and forms part of terminal care. During the terminal phase restlessness, anxiety, pain, and dyspnoea require the most attention. Treatment requires careful multidisciplinary cooperation.     

The dyspnea-anxiety-dyspnea cycle--COPD patients' stories of breathlessness: "It's scary /when you can't breathe"

Dyspnea, the major symptom associated with acute exacerbation events of chronic obstructive pulmonary disease (COPD), is a subjective experience. Extensive research has been done on the pathophysiology and affective components of dyspnea; however, the precise physical mechanism of breathlessness remains elusive. One purpose of this narrative research was to explore the affective component of dyspnea/anxiety as described by patients living with COPD characterized by acute illness events. Ten patient-family units participated in interviews during an acute episode of the patient's lung disease. They described their understanding of acute dyspnea as an experience inextricably related to anxiety and emotional functioning. Their stories suggest that given the absence of clear objective measures of illness severity, patient-reported anxiety might provide an important marker during acute exacerbation events. Health care providers need to recognize anxiety as an important and potentially measurable sign of invisible dyspnea for end-stage patients with COPD in acute respiratory distress.     

Inclusion Body Myositis: A Case of Bilateral Extremity Weakness

Inflammatory myopathy is a common cause of bilateral muscular weakness in adults. Although not as common as polymyositis, inclusion body myositis (IBM) is a form of inflammatory myopathy characterized by chronic progressive muscle inflammation and often goes undiagnosed and untreated. IBM patients most commonly present with proximal lower extremity weakness and may have normal creatine kinase (CK) levels. A high level of clinical suspicion is required for prompt and accurate diagnosis of IBM, which is diagnosed definitively with a muscle biopsy. The patient described in this case report is a 68-year-old man who initially presented with both bilateral symmetric proximal lower extremity and distal upper extremity weakness. IBM was suspected through history, electromyography, and definitively diagnosed with muscle biopsy. The patient was subsequently initiated on prednisone therapy and physical therapy, with improvement in muscular strength after 2 months. In patients presenting with bilateral extremity weakness and normal CK level, the diagnosis of IBM should be included in the differential diagnosis and muscle biopsy performed for appropriate cases.     

Long-Term Symptoms among COVID-19 Survivors in Prospective Cohort Study,Brazil

We conducted a prospective cohort study in a population with diverse ethnic backgrounds from Brazil to assess clinically meaningful symptoms after surviving coronavirus disease. For most of the 175 patients in the study, clinically meaningful symptoms, including fatigue, dyspnea, cough, headache, and muscle weakness, persisted for >120 days after disease onset.     

A limited epidemiological study of seropositive myasthenia gravis in Tayside

Myasthenia gravis is an acquired disorder of the neuromuscular junction characterised by fatiguable weakness of the limbs, bulbar and facial muscles and may be complicated by respiratory muscle weakness and failure. One often confirms the diagnosis by a simple serological test looking for the presence of the nicotinic acetylcholine receptor antibody. However, seronegative myasthenia constitutes about 20% of cases and in the case of ocular myasthenia, only 50% will have the antibody. Therefore, the diagnosis can be less than straightforward especially if the patient presents with vague symptoms such as fatigue or presents to specialities other than neurology or ophthalmology. The fact that the diagnosis may prove to be challenging, compounded by the fact that the condition is relatively rare and that the antibody to the acetylcholine receptor is not always present, epidemiological data is often less than precise and indeed difficult to acquire. We felt it was necessary to try to establish the epidemiological data on seropositive myasthenia gravis in Tayside, (this has never been carried out) bearing in mind the above pitfalls, and see how the incidence compares with similar and previous studies.     

"Critical-illness" polyneuropathy and -myopathy

Critical-illness polyneuropathy and myopathy (CIPNM) can be considered a part of the syndrome of multiple organ dysfunction. CIPNM is the commonest cause of muscle weakness acquired in the intensive care unit. Its incidence is 35-80% during prolonged mechanical ventilation. For a (differential) diagnosis, electrophysiological investigations are usually necessary, and sometimes a muscle biopsy. CIPNM may be induced by triggering of the immune response leading to increased vascular permeability with tissue invasion of inflammatory cells and local damage. There is a relation between myopathy and medication, notably corticosteroids. Clinical improvement usually follows when the CIPNM patient survives the underlying disease, but weaning from artificial ventilation is often difficult, and rehabilitation prolonged.     

北京地区2010年10月-2011年5月急性呼吸道感染病毒临床特征分析

目的:分析急性呼吸道感染的临床特征,为临床特异性诊断和治疗,以及呼吸道传染病的防治提供依据。方法:选取2010年10月-2011年5月采集的352份呼吸道感染病例,收集病例的临床资料,采集咽拭子样本,检测呼吸道相关病毒,用SPSS软件进行统计分析。结果:352病例中,病毒检测阳性率为39.2%,多份标本存在合并感染,感染病例80%以上都有咳嗽症状,50%以上有发热症状,乙型流感病毒感染患者中头痛的比例(100%)和胸痛的比例(50%)远高于其他患者;MPV感染患者呼吸困难的比例要远高于其他。甲型流感病毒单纯感染和腺病毒单纯感染的标本中头痛的比例要高于有其他病毒合并感染的标本。结论:不同呼吸道病毒感染有一定的临床特征,且各病毒之间易发生合并感染。合并感染的临床表现与单纯病毒感染略有不同。     

Pseudo-polymyositic aspect of amyotrophic lateral sclerosis

The causes of skeletal muscle weakness are multiple and their diagnosis is difficult, particularly in atypical myopathy. We report the observation of 58-old woman, who presents a muscle weakness of lower limbs with elevation of muscle's enzymes. These symptoms were bound initially to polymyosistis. However, the absence of inflammatory biologic syndrome and the results of muscular biopsy, make this diagnosis unlikely. The aggravation of the myopathy with extension to spinal muscles, the apparition of fasciculations and bulbar signs, the results of the electromyogram pose the diagnosis of amyotrophic lateral sclerosis.     

Clinical characteristics of nursing home residents hospitalized with heart failure

OBJECTIVE: The purpose of this retrospective study was to describe the clinical characteristics of heart failure among nursing home residents hospitalized with heart failure and determine the validity of dyspnea at rest in the diagnosis of heart failure. METHODS: Subjects were nursing home residents hospitalized with a diagnosis of heart failure. Data on demographic and various admission characteristics were collected by chart abstraction. Proportions of patients presenting with various symptoms and signs of heart failure have been described. The diagnosis of heart failure was confirmed using modified Framingham criteria. The sensitivity, specificity, and positive predictive value of the symptom of dyspnea at rest in the diagnosis of heart failure in nursing home residents hospitalized with heart failure were then estimated. RESULTS: Patients (N = 98) were elderly, predominantly female and about one-fifth African-American. Dyspnea at rest was the presenting symptom of 85 (87%) patients. Sixty-eight (69%) patients met modified Framingham criteria for the diagnosis of heart failure. Dyspnea at rest had a sensitivity of 91%, specificity of 23%, and predictive value positive of 73% for diagnosis of heart failure. CONCLUSION: Dyspnea at rest was the most common symptom among this cohort of nursing home residents hospitalized with heart failure and has a potential to play a useful role in the diagnosis of heart failure in these patients.     

Critical illness myopathy: what is happening?

PURPOSE OF REVIEW: The current review focuses on recent studies, both clinical and from basic sciences, which approach possible pathomechanisms of critical illness myopathy in order to better derive potential clinical strategies for a preventive or curative clinical setting. Trends and concepts of clinical diagnosis and handling will be evaluated and their implications for muscle physiology and nutritional/metabolic intervention discussed. RECENT FINDINGS: Conventional electrophysiology was combined with direct muscle stimulation to better differentiate critical illness myopathy from other neuromuscular disorders in critical illness. Muscle weakness was the result of impaired excitation-contraction-coupling at the level of the sarcolemma and the sarcoplasmic reticulum membrane. Critical illness may alter sodium and ryanodine receptor calcium-release channels. Also, increased muscle proteolysis contributes to weakness in critical illness myopathy. Myosin loss is due to the risk factors systemic inflammatory response syndrome/sepsis, steroids and neuromuscular blocking agents. Steroids can also induce necrosis and apoptosis in muscle. Inflammatory mediators aggravated muscle metabolic failure in critical illness myopathy. Ubiquitin-proteasome pathways, cyclooxygenase activation, altered glucose transporter expression, MyoD suppression, impaired respiratory chain enzymes, ATP depletion, glucose toxicity and insulin resistance can all contribute to the critical illness myopathy pathomechanism. SUMMARY: The search for pathomechanisms is an important task for both clinical and basic sciences. Targets for treatment or prevention of critical illness myopathy include systemic inflammatory response, increased proteolysis and reduced antioxidative capacitance in critically ill patients.