Respiratory Muscle Involvement Research Articles

Screening for sleep-disordered breathing in neuromuscular disease using a questionnaire for symptoms associated with diaphragm paralysis

Patients with neuromuscular disease (NMD) are at risk of developing sleep-disordered breathing (SDB) following respiratory muscle involvement. We hypothesised that a questionnaire based on clinical symptoms and signs of diaphragm weakness can be used to screen for SDB in such patients. We developed a self-administered multiple choice questionnaire containing five questions (Sleep-Disordered Breathing in Neuromuscular Disease Questionnaire (SiNQ)-5), scoring 0-10 points. 125 patients were enrolled: 32 with respiratory muscle weakness, 35 subjects with normal respiratory muscle strength and 58 patients with obstructive sleep apnoea (OSA). All subjects underwent full polysomnography. NMD patients with involvement of the respiratory muscles scored mean ± sd 6.8 ± 2.3 out of 10 points, significantly higher than both OSA patients 2.5 ± 2.3 and normal subjects 1.0 ± 2.0 (p < 0.001). A score of five or more points in the SiNQ-5 had a sensitivity of 86.2%, specificity of 88.5%, positive predictive value of 69.4% and a negative predictive value of 95.5% to identify NMD with combined SDB. A short self-administered questionnaire, the SiNQ-5, based on clinical symptoms can reliably screen for SDB in patients with diaphragm weakness. However, comorbidities, such as heart failure, that have symptoms influenced by posture could alter diagnostic accuracy.

166th ENMC International Workshop on Collagen type VI-related Myopathies, 22–24 May 2009, Naarden, The Netherlands

Twenty-four clinicians, basic scientists and representatives of a patient advocacy organisation and pharmaceutical companies from 8 countries (Australia, England, France, Germany, Italy, Switzerland, Turkey, USA) gathered in Naarden, The Netherlands, to discuss the group of neuromuscular disorders caused by the deficiency of collagen type VI (ColVI), collectively termed ColVI-related myopathies. This meeting focused on three main areas: (1) the great heterogeneity observed at the genetic and clinical levels and the resulting complexity of the molecular diagnosis; (2) the pathophysiological mechanisms linking mutations in the COL6A genes to muscle pathology; (3) the current strategies for therapeutic interventions which have led to the design of upcoming clinical trials. Two sessions were also dedicated to existing and future databases, and to outcome measures.

Pulmonary function tests and diaphragmatic compound muscle action potential in patients with sporadic amyotrophic lateral sclerosis

Respiratory failure is the primary cause of death in patients with amyotrophic lateral sclerosis (ALS). Diaphragmatic compound muscle action potentials (DCMAP) are valid parameters to assess the respiratory muscle innervation. In this study we propose to establish evidence of pulmonary dysfunction in patients with ALS and its relation to DCMAP parameters among patients with sporadic ALS. Twenty nine patients (M-20, F-9) diagnosed to have sporadic ALS by El. Escorial criteria, without symptoms of pulmonary dysfunction, and able to perform the PFT satisfactorily, were studied. Thirty controls (M-20, F-10) were selected from patient's relatives. Forced vital capacity (FVC), forced expiratory volume in one second (FEV(1)), peak expiratory flow rate (PEFR) and maximum voluntary ventilation (MVV) were measured by spirometry. Maximum expiratory pressure (MEP) was measured by digital peak pressure monitor. Right phrenic nerve conductions (DCMAP) were performed and the latencies and amplitude of diaphragmatic com-pound action potential (DCMAP) was recorded in controls and ALS patients. The mean age of patients was 51.41 +/- 10.72 years (37-82) and control was 53.57 +/- 8.85 years (30-68). None of the patients had symptoms or clinical evidence of respiratory dysfunction. The FVC, FEV1, PEFR, MVV, MIP and MEP were significantly (P < 0.001) reduced in ALS. The mean DCMAP amplitude was reduced among patients (610 +/- 506.231 muv) as compared to controls (1303.33 +/- 584.56, P < 0.001) and mean latency was increased in patients (9.73 +/- 2.57 ms) compared to controls (7.69 +/- 0.87, P = 0.001). There was significant negative correlation between PFTs and latencies of DCMAP. Amplitude of DCMAP did not correlate with PFTs. There is significant negative correlation between DCMAP latencies and PFTs suggesting early loss of myelinated fibres and diaphragmatic dysfunction. DCMAP latencies may be a good indicator of early respiratory muscle involvement and also of disease progression in ALS.

ALS with respiratory onset: Clinical features and effects of non-invasive ventilation on the prognosis

Respiratory muscle involvement is one of the main prognostic factors in amyotrophic lateral sclerosis (ALS). Acute respiratory failure is sometimes the first manifestation of the disease, although onset can be more insidious. In the present retrospective study, it was proposed to review the clinical features and to assess the effects of non-invasive ventilation (NIV) on the prognosis of patients with respiratory onset, which was taken to be present when the first symptoms of muscular weakness were dyspnoea at exertion, dyspnoea at rest, or orthopnoea. Respiratory onset ALS is uncommon, since it accounts for less than 3% of ALS cases. ALS with respiratory onset has some common clinical features: male predominance, frequent camptocormia or dropped head, frequent widespread fasciculations, limb mobility fairly well preserved and significant weight loss in the early stages. ALS patients with respiratory onset still have a poor prognosis compared with those with bulbar or spinal forms. NIV should be proposed promptly because it improves the symptoms, general state of health and survival time. Efforts should be made to inform general practitioners and chest physicians and remind them that neuromuscular respiratory insufficiency may be attributable to this particular form of ALS.

Mechanisms of exercise limitation and pulmonary rehabilitation for patients with neuromuscular disease

Indications for exercise and pulmonary rehabilitation extend to neuromuscular diseases tough these conditions pose particular challenges given the associated skeletal muscle impairment and respiratory muscle dysfunction. These challenges are compounded by the variety of exercise prescriptions (aerobic, muscle strengthening, and respiratory muscle training) and the variety of neuromuscular disorders (muscular, motor neuron, motor nerve root, and neuromuscular transmission disorders). Studies support a level II evidence of effectiveness (i.e., likely to be effective) for a combination of aerobic exercise and strengthening exercises in muscular disorders, and for strengthening exercises in amyotrophic lateral sclerosis. The potential deleterious effects of work overload in the dystrophinopathies have not been confirmed in Becker muscular dystrophy. Adjunctive pharmacologic interventions (e.g., theophylline, steroids, PDE5 inhibitors, creatine), training recommendations (e.g., interval or lower intensity training) and supportive techniques (e.g., noninvasive ventilation, neuromuscular electrical stimulation, and diaphragm pacing) may result in more effective training but require more study before formal recommendations can be made. The exercise prescription should include avoidance of inspiratory muscle training in hypercapnia or low vital capacity, and should match the desired outcome (e.g., extremity training for task-specific performance, exercise training to enhance exercise performance, respiratory muscle training where respiratory muscle involvement contributes to the impairment).

Dyspnée à l’effort chez le patient atteint de sclérodermie systémique : du symptôme au diagnostic étiologique

Pulmonary hypertension and interstitial lung disease are the two main causes of death in systemic sclerosis. The hallmark of these complications is dyspnea on exertion. Assessment of dyspnea in systemic sclerosis is based on a questionnaire; 6-minute walk test and Borg index. After excluding anemia, a deceptive cause mainly due to digestive haemorrhage, echocardiography, pulmonary function tests and high resolution computed tomography of the chest are the first step to diagnosis. Peak velocity of tricuspid regurgitation as measured by echocardiography is the main parameter to evaluate the risk of pulmonary hypertension before performing a right heart catheterization. Diastolic left ventricle dysfunction is another frequently encountered cause of dyspnea in systemic sclerosis. Other less common causes are pericarditis, respiratory muscle involvement, lung cancer, pulmonary embolism.

Guillain-Barré Syndrome with asystole requiring permanent pacemaker: a case report

IntroductionGuillain-Barré syndrome is an acute demyelinating disorder of the peripheral nervous system that results from an aberrant immune response directed at peripheral nerves. Autonomic abnormalities in Guillain-Barré syndrome are usually transient and reversible. We present a case of Guillain-Barré syndrome requiring a permanent pacemaker in view of persistent symptomatic bradyarrhythmia.Case PresentationAn 18-year-old Caucasian female presented with bilateral lower limb paraesthesias followed by bilateral progressive leg weakness and difficulty in walking. She reported an episode of an upper respiratory tract infection 3 weeks prior to the onset of her neurological symptoms. Diagnosis of Guillain-Barré syndrome was considered and a lumbar puncture was performed. Cerebrospinal fluid revealed albuminocytologic dissociation (increased protein but normal white blood cell count) suggestive of Guillain-Barré syndrome and hence an intravenous immunoglobulin G infusion was started. Within 48 hours, she progressed to complete flaccid quadriparesis with involvement of respiratory muscles requiring mechanical ventilatory support. Whist in the intensive care unit, she developed multiple episodes of bradycardia and asystole requiring a temporary pacemaker. In view of the persistent requirement for the temporary pacemaker for more than 5 days, she received a permanent pacemaker. She returned for follow-up three months after discharge with an intermittent need for ventricular pacing.ConclusionGuillain-Barré syndrome can result in permanent damage to the cardiac conduction system. Patients with multiple episodes of bradycardia and asystole in the setting of Guillain-Barré syndrome should be evaluated and considered as potential candidates for permanent pacemaker implantation.

FINE-MAPPING THE GENE FOR X-LINKED MYOPATHY WITH EXCESSIVE AUTOPHAGY

Myopathies with autophagic vacuoles with sarcolemmal features (MAVSF) are a group of skeletal muscle diseases exhibiting autophagic vacuolation of myofibers. The vacuoles have membranes of mixed sarcolemmal, lysosomal, and autophagosomal origin. They contain partially degraded cell components including proteins, glycogen, membrane whorls, and organelles.1 The two most common MAVSF are Danon disease and X-linked myopathy with excessive autophagy (XMEA). Danon disease is caused by mutations in the LAMP2B isoform of the lysosome-associated membrane protein-2 ( LAMP2 ) gene.2 LAMP2B may play a role in approaching lysosomes to merge with autophagosomes.1 The genes for XMEA and the other MAVSF are unknown. We previously mapped the XMEA gene to chromosomal band Xq28, one of the most gene-rich regions of the genome, in a 4.64 Mb locus containing over 110 genes.3 We now refine this locus to 0.58 Mb containing only six genes. XMEA is inherited recessively, affecting boys and sparing carrier females. Onset is between ages 6 and 18 years with weakness and gradual wasting of the proximal muscles of the lower extremities. Other skeletal muscle groups are progressively affected including the upper limb girdle and distal muscles. Patients are wheelchair-bound in their 50s, and lifespan appears to be shortened due to respiratory muscle involvement. Considerable variation from this clinical picture can be seen, with some patients exhibiting extremely mild and sometimes no weakness or wasting (see below). The central and …

Vocal cord paresis and diaphragmatic dysfunction are severe and frequent symptoms of GDAP1-associated neuropathy

Cranial nerve involvement in Charcot-Marie-Tooth disease (CMT) is rare, though there are a number of CMT syndromes in which vocal cord paralysis is a characteristic feature. CMT disease due to mutations in the ganglioside-induced differentiation-associated protein 1 gene (GDAP1) has been reported to be associated with vocal cord and diaphragmatic palsy. In order to address the prevalence of these complications in patients with GDAP1 mutations we evaluated vocal cord and respiratory function in nine patients from eight unrelated families with this disorder. Hoarseness of the voice and inability to speak loudly were reported by eight patients and one had associated symptoms of respiratory insufficiency. Patients were investigated by means of peripheral and phrenic nerve conduction studies, flexible laryngoscopy, pulmonary function studies and polysomnography. Nerve conduction velocities and pathological studies were compatible with axonal CMT (CMT2). Flexible laryngoscopy showed left vocal cord palsy in four cases, bilateral cord palsies in four cases and was normal in one case. Restrictive respiratory dysfunction was seen in the eight patients with vocal cord paresis who were all chair-bound. These eight had confirmed phrenic nerve dysfunction on neurophysiology evaluation. The patient with normal vocal cord and pulmonary function had a less severe clinical course.This study shows that CMT patients with GDAP1 mutations develop severe disability due to weakness of limb muscles and that laryngeal and respiratory muscle involvement occurs late in the disease process when significant proximal upper limb weakness has developed. The early and predominant involvement of the left vocal cord innervated by the longer left recurrent laryngeal nerve suggests a length dependent pattern of nerve degeneration. In GDAP1 neuropathy, respiratory function should be thoroughly investigated because life expectancy can be compromised due to respiratory failure.

Acute Respiratory Failure as Initial Presentation of Amyotrophic Lateral Sclerosis Onset

Amyotrophic lateral sclerosis (ALS) is a progressive, unrelenting and presently incurable neurodegenerative disorder. Respiratory muscle involvement is often a late complication of ALS. Only 1–3% of patients with ALS presenting to a tertiary care center had respiratory symptoms as their initial clinical symptom. In addition, only 14% of these individuals presented acutely and required emergency intubation. We report a 75-year-old female whose initial presentation at our emergency department was dyspnea. Dyspnea worsened and progressed to acute respiratory failure. There was no definite cause of respiratory failure found initially. However, ALS was diagnosed after physical and neurologic examination and electrodiagnostic studies. Respiratory muscle weakness was her first presentation of ALS.

Sleep disordered breathing in childhood-onset acid maltase deficiency

Objectives: To clarify the feature of sleep disordered breathing (SDB) associated with childhood-onset acid maltase deficiency (AMD): the progressive nature of SDB and the stage of AMD. Study design: We retrospectively studied 4 patients with childhood-onset AMD by analyzing the results of neurological examinations for muscle wasting and muscle strength and the data on venous gas and from a pulmonary function test and nocturnal polysomnography (PSG). Results: Three out of the 4 patients showed muscular symptoms including myalgia, lordoscoliosis, muscle wasting and muscle weakness. They also complained of sleep-related symptoms such as tiredness in the morning and daytime sleepiness. All of them showed SDB by PSG, even in a patient in the earliest stage who exhibited no signs or symptoms of muscle weakness. In 3 patients, noninvasive intermittent positive pressure ventilation during sleep was introduced; and thereafter sleep-related symptoms were resolved and no lower respiratory infection reoccurred. Although their quality of life was improved, no improvement of respiratory function was shown by spirometry over a 2-year follow-up period. Conclusions: SDB seems to be common in childhood-onset AMD, which is not always accompanied by daytime muscular symptoms, especially in mild patients. PSG should be utilized for detecting SDB, which could be one of the earliest signs of respiratory muscle involvement in childhood-onset AMD.

Factors Predicting Survival following Noninvasive Ventilation in Amyotrophic Lateral Sclerosis

Background/Aims: The involvement of respiratory muscles is a major predicting factor for survival in amyotrophic lateral sclerosis (ALS). Recent studies show that noninvasive ventilation (NIV) can relieve symptoms of alveolar hypoventilation. However, factors predicting survival in ALS patients when treated with NIV need to be clarified. Methods: We conducted a retrospective study of 33 consecutive ALS patients receiving NIV. Ten patients had bulbar onset. We determined the median survivals from onset, diagnosis and initiation of NIV and factors predicting survival. Statistical analysis was performed using the Kaplan-Meier test and Cox proportional hazard models. Results: The median initial and maximal total uses of NIV were 10 and 14 h/24h. The overall median survival from ALS onset was 34.2 months and worsened with increasing age and bulbar onset of the disease. The median survival from initiation of NIV was 8.4 months and was significantly poorer in patients with advanced age or with airway mucus accumulation. Survival from initiation of NIV was not influenced by respiratory parameters or bulbar symptoms. Conclusion: Advanced age at diagnosis and airway mucus accumulation represent poorer prognostic factors of ALS patients treated with NIV. NIV is a helpful treatment of sleep-disordered breathing, including patients with bulbar involvement.

Severe neonatal non‐dystrophic myotonia secondary to a novel mutation of the voltage‐gated sodium channel (SCN4A) gene

We report on a patient with a severe, rare neonatal form of non-dystrophic myotonia. The patient presented with facial dysmorphism, muscle hypertrophy, severe constipation, psychomotor delay, and frequent cold-induced episodes of myotonia and muscle weakness leading to severe hypoxia and loss of consciousness. Muscle biopsy was non-specific and electromyography revealed intense generalized myotonia. The myotonic episodes improved after introducing oral mexiletine and maintaining room temperature at 28 degrees C. The patient died at 20 months of age following a bronchopulmonary infection. A previously undescribed de novo heterozygous c.3891C > A change, which predicts p.N1297K in the SCN4A gene. Mutations within the voltage-gated sodium channel alpha-subunit gene (SCN4A) have been described in association with several phenotypes including paramyotonia congenita, hyperkalemic or hypokalemic periodic paralysis, and potassium-aggravated myotonias. The cold-sensitive episodes of stiffness followed by weakness suggested the diagnosis of channelopathy in our patient. However, her neonatal onset, the triggering of severe episodes by exposure to modest decreases in temperature, involvement of respiratory muscles with prolonged apnea, early-onset muscle hypertrophy, psychomotor retardation, and fatal outcome are evocative of a distinct clinical subtype. Our observation expands the phenotypic spectrum of sodium channelopathies.

Myopathie des muscles inspiratoires au cours du syndrome des antisynthétases

Respiratory muscle involvement is a rarely reported manifestation of inflammatory myopathies. We report the case of a 38-year-old woman with antisynthetase syndrome who presented with inflammatory myopathy and acute pulmonary interstitial involvement that initially improved with corticosteroids and immunoglobulins. A few months later dyspnoea resumed despite the absence of evidence of interstitial deterioration or other common diagnosis including vascular or infectious disorders. Isolated respiratory muscular involvement was evidenced by functional testing. Disease course was favourable with corticosteroids and immunoglobulins. Inflammatory myopathy of the antisynthetases syndrome could be limited or mainly expressed to respiratory muscles. Unexplained dyspnoea should call in mind a muscular respiratory myositis.

Novel mutation in KCNA1 causes episodic ataxia with paroxysmal dyspnea

Episodic ataxia type 1 (EA1) is an autosomal-dominant neurological disease caused by point mutations in the potassium channel-encoding gene KCNA1. It is characterized by attacks of ataxia and continuous myokymia. Respiratory muscle involvement has not been previously reported in EA1. We clinically evaluated a family with features of EA1 and paroxysmal shortness of breath. Coding and flanking intronic regions of KCNA1 were sequenced. We identified a novel 3-nucleotide deletion mutation in KCNA1 in the affected individuals. Our findings of a deletion mutation with unusual respiratory muscle involvement expand the genetic and clinical spectrum of EA1.

Nemaline myopathy revealed by respiratory failure in adults

Summary Most forms of myopathy may involve the respiratory muscles and progress to respiratory failure. However, the diagnosis of myopathy is seldom considered in an adult patient with no history of muscle disease and presenting with respiratory failure. Nemaline myopathy (NM) is a rare disorder characterized by symmetrical diffuse muscle weakness and rod-like nemaline bodies in muscle fibers. Respiratory muscle involvement is a major determinant of mortality in congenital NM, but is rare in late onset NM. Here, we report that acute or chronic respiratory failure may be caused by NM in subjects with no known history of muscle disease. Adult-onset NM was diagnosed in a 67-year-old woman with chronic respiratory insufficiency. Late onset childhood NM was revealed by respiratory failure in twin sisters aged 31. The diagnosis was established by muscle biopsy and electron microscopy (and mutations in the nebulin gene in the two sisters). Long-term clinical improvement was obtained with non-invasive ventilation (NIV) in the three patients. In conclusion, respiratory failure in an adult patient with no known history may correspond to NM with diaphragm involvement. Long-term outcome may be favorable with NIV.

A Case of Hypercapnic Respiratory Failure in a Patient with Eosinophilic Polymyositis

Eosinophilic infiltration into skeletal muscles has been rarely reported in a variety of conditions such as parasite infection, sarcoidosis, rheumatoid arthritis, eosinophilia-myalgia syndrome, and idiopathic hypereosinophilic syndrome. Eosinophilic myositis (EM) is one of idiopathic inflammatory muscle diseases associated with muscle and/or blood eosiophilia. The case of EM complicated with hypercapnic respiratory failure has been extremely rarely reported. A 61-year-old woman was admitted with sudden-onset pain in both calves. She had elevated serum muscle enzymes and peripheral eosinophil count. Findings of electromyography were consistent with inflammatory myopathy. MRI showed diffuse hyperintensity of calf muscles on T2-weighted and enhanced T1 images. Muscle biopsy showed eosinophils' infiltration in the endomysium and perivascular area. During the diagnostic work-up, she presented with hypercapnic respiratory failure. She was successfully treated with mechanical ventilation and high doses of prednisolone. This case suggests EM can cause respiratory failure secondary to respiratory muscle involvement.

Amyotrophic lateral sclerosis: can we predict the course of disease?

A variety of prognostic factors have been associated with survival and disease progression in amyotrophic lateral sclerosis (ALS). With knowledge of factors that affect prognosis, clinicians can best advise their patients about their future clinical course. Moreover, the evaluation of early prognostic variables and the understanding of first exam factors related to outcome may impact on the selection of patient cohorts for clinical trails. This goal is highly desirable, since the appropriate stratification of eligible patients based on the described predictors could result in reduction of sample size and study duration. It is well known that factors like age, sex, site of symptom onset and diagnostic delay, if imbalanced among treatment groups, may have a larger effect on outcome in the clinical ALS trials than the treatment itself. Thus, matching patients for established demographic and clinical parameters is particularly important in planning clinical trials. However, the randomisation for too many variables in the entry criteria may cause a large increase in the number of patients needed to balance the trial. Based on our own data we describe here the value of prognostic factors related to outcome in patients with ALS and review the literature. The identification of younger age, limb site of onset and longer FS-FE delay as predictors of prolonged survival in an ALS clinic population is in agreement with the findings of several earlier studies that were based on smaller groups of patients. Moreover, given the well-known correlation between disease progression and survival, our finding that age at onset, time between first symptom and first examination, and site of symptom onset also act as significant and independent covariates of disease progression might be expected, although it remains at odds with certain previous reports. Younger age at the time of symptoms onset is clearly associated with slower disease progression. In addition, younger patients survive significantly longer even after adjustment for potentially confounding factors. Patients with limb symptoms at onset survived remarkably longer than bulbaronset patients. Moreover, in patients exhibiting limb symptoms at onset a slower disease progression was observed. We hypothesise that bulbar-on-set patients may have shortened survival and faster disease progression from earlier involvement of respiratory muscles, a higher rate of respiratory complications, malnutrition and dehydration. The delay between symptom onset and first examination (FS-FE time or disease duration at diagnosis) was a robust predictor of survival and disease progression in our studies as in others. This delay was negatively related to hazard, i.e. positively related to length of survival - in other words, the longer the delay, the longer the survival and the slower the disease progression. In our patient population patients whose first examination was longer than 12 months after first symptom survived longer compared with patients who were first examined within 12 months after the onset of symptoms. Furthermore, longer time between first symptom (FS) and first examination (FE) was associated with slower disease progression. These findings support the hypothesis that the time between first symptom and first clinical examination may be a measure of the initial rate of disease progression. The more rapidly a patient initially deteriorates, the shorter the delay before the first symptom and first examination. These results suggest that fast progressing patients tend to seek medical care earlier, whereas those with slower disease progression are referred later or adapt to first symptoms for a longer time before they visit a medical care facility.

Maladies neuromusculaires : évaluation des fonctions ventilatoires

Involvement of respiratory muscles is a nearly constant feature of neuromuscular disorders, leading to respiratory failure. A careful respiratory follow up adapted to the variable time course of each disease is therefore mandatory. As the first step, a systematic clinical evaluation is essential to detect the subtle respiratory symptoms and signs related to respiratory muscle failure. Dyspnea and orthopnea are often late findings in patients with a usually severe functional impairment due to peripheral muscle weakness. Nocturnal respiratory events (obstructive sleep apnea syndrome and hypoventilation) are strongly suggested by daytime hypersomnolence and frequent morning headaches. Physical evaluation is essential to detect accessory muscle recruitment, supine abdominal paradox, and encumbrance of upper or lower airways. Vital capacity (VC) is the most classical lung function test. The major limitation of spirometry is its poor sensitivity to detect a moderate inspiratory muscle weakness. Supine VC may improve the detection of diaphragmatic involvement. Peak expiratory flow during cough (cough PEF) gives an overall evaluation of cough efficiency, values below 160 to 270 L/min suggesting poor airway clearance. Arterial blood gases are performed in case of clinical signs, significant deterioration of lung function tests, or sleep desaturations. Hypercapnia is weakly related to lung function results in patients with Steinert dystrophy and those with bulbar involvement. A specific evaluation of respiratory muscle strength is mandatory, as these tests are both sensitive and highly prognostic. Possible discrepancies (particularly in bulbar patients) between maximal inspiratory pressure (PImax) and sniff nasal inspiratory pressure (SNIP) justify to perform both measurements and to select the highest pressure. A maximal expiratory pressure (PEmax) below 45 cm H2O may indicate a compromised cough efficiency but the correlation with cough PEF may be poor. A screening nocturnal oxymetry is useful to detect sleep apneas and hypoventilation. Criteria defining significant desaturations remain however controversial. Suspicion of obstructive sleep apnea syndrome on clinical grounds or oxymetry findings should be confirmed by a conventional polysomnography.

National registry of patients with juvenile idiopathic inflammatory myopathies in Hungary—Clinical characteristics and disease course of 44 patients with juvenile dermatomyositis

Idiopathic inflammatory myopathies (IIMs) are systemic autoimmune diseases characterized by chronic muscle inflammation resulting in progressive weakness and frequent involvement of internal organs, mainly the pulmonary, gastrointestinal and cardiac systems which considerably contribute to the morbidity and mortality of the IIMs.Aim of this study was to present clinical characteristics, disease course, frequency of relapses and survival in patients with juvenile dermatomyositis (DM).A national registry of patients with juvenile IIMs was elaborated by the authors in Hungary. We have summarized data of the register according to signs and symptoms, disease course, frequency of relapses and survival of patients with juvenile IIM. Analysis was performed using data of 44 patients with juvenile DM diagnosed between 1976 and 2004 according to Bohan and Peter's criteria. Survival probability was calculated by Kaplan–Meier method.Data of patients with juvenile DM were compared with data of 66 patients with adult DM. The most frequent cutaneous features were facial erythema and heliotrope rash. Extramuscular and extraskeletal manifestations of the disease were more frequent in adult patients. The most common extramuscular feature was arthralgia in both groups of patients with juvenile or adult DM. Cardiac manifestation of the disease was not observed in juvenile patients. Respiratory muscle involvement and interstitial lung disease (ILD) were more frequent among adult DM patients than cardiac manifestation of the myositis. In view of the disease course, the authors found that frequency of polycyclic and monophasic subtypes of the disease were mainly similar. The hazard of relapse was found higher during the first year after the remission. None of the juvenile patients died. Among adult patients four disease-specific deaths occurred. There was no correlation between relapse free survival and initial therapeutic regimen. Many of our patients had polycyclic or chronic disease. As relapses can occur after a prolonged disease-free interval, patients should be followed up for at least 2 years. Although we found favourable survival probability, further investigations are needed to assess functional outcome.