Airway obstruction in Hurler's syndrome--radiographic features

Chest wall volumes, diaphragmatic mobility, and functional capacity in patients with mucopolysaccharidoses

PURPOSE

We investigated respiratory muscle strength, diaphragm mobility, lung function, functional capacity, quality of life, body composition, breathing pattern, and chest wall (V_T,CW) and compartmental volumes of Mucopolysaccharidosis (MPS) patients and compared these variables with matched healthy individuals.

METHODS

A cross-sectional study with data analyzed separately according to age group. A total of 68 individuals (34 MPS and 34 matched-healthy subjects) were included. Six-minute walking test assessed functional capacity and ultrasound assessed diaphragm mobility during quiet spontaneous breathing (QB). Optoelectronic plethysmography assessed V_T,CW and breathing pattern during QB in two different positions: seated and supine (45° trunk inclination).

RESULTS

Body composition, lung function, respiratory muscle strength, and functional capacity were reduced in MPS (all p < 0.01). Diaphragm mobility was only reduced in adolescents (p = 0.01) and correlated with body composition and breathing pattern. Upper chest wall compartmental volumes were significantly lower in MPS, while abdominal volume only differed significantly in adolescents. Percentage contribution (%) of upper ribcage compartments to tidal volume was reduced in MPS children, whereas %AB was significantly increased compared with healthy subjects.

CONCLUSION

Lung function, respiratory muscle strength, functional capacity, diaphragm mobility, and quality of life are reduced in MPS compared with matched healthy subjects. V_T,CW was mainly reduced due to pulmonary and abdominal ribcage impairment. Implications for RehabilitationReduction in respiratory muscle strength, functional capacity, diaphragm excursion and low lung volumes were found in individuals with Mucopolysaccharidoses (MPS).Chest wall volumes and the upper chest wall compartmental volumes during quiet spontaneous breathing are reduced in MPS.Assessment and monitoring of the respiratory system for individuals with MPS should be performed periodically through standardized assessments to enable identification of changes and early intervention by rehabilitation protocols.This study may provide the necessary basis for carrying out respiratoty rehabilitation protocols that can improving chest wall mechanics with breathing exercise in this group.

Pulmonary Manifestations of Endocrine and Metabolic Diseases in Children

Advances in technology, methodology, and deep phenotyping are increasingly driving the understanding of the pathologic basis of disease. Improvements in patient identification and treatment are impacting survival. This is true in endocrinology and inborn errors of metabolism, where disease-modifying therapies are developing. Inherent to this evolution is the increasing awareness of the respiratory manifestations of these rare diseases. This review updates clinicians, stratifying diseases spirometerically; pulmonary hypertension and diseases with a predisposition to recurrent pulmonary infection are discussed. This division is artificial; many diseases have multiple pathologic effects on respiration. This review does not cover the impact of obesity.

Respiratory complications of metabolic disease in the paediatric population: A review of presentation, diagnosis and therapeutic options

Inborn errors of metabolism (IEMs) whilst individually rare, as a group constitute a field which is increasingly demands on pulmonologists. With the advent of new therapies such as enzyme replacement and gene therapy, early diagnosis and treatment of these conditions can impact on long term outcome, making their timely recognition and appropriate investigation increasingly important. Conversely, with improved treatment, survival of these patients is increasing, with the emergence of previously unknown respiratory phenotypes. It is thus important that pulmonologists are aware of and appropriately monitor and manage these complications. This review aims to highlight the respiratory manifestations which can occur. It isdivided into conditions resulting primarily in obstructive airway and lung disease, restrictive lung disease such as interstitial lung disease or pulmonary alveolar proteinosis and pulmonary hypertension, whilst acknowledging that some diseases have the potential to cause all three. The review focuses on general phenotypes of IEMs, their known respiratory complications and the basic metabolic investigations which should be performed where an IEM is suspected.

CT and endoscopic evaluation of larynx and trachea in mucopolysaccharidoses

BACKGROUND

Mucopolysaccharidoses (MPSs) are lysosomal storage disorders caused by lysosomal enzyme deficiencies that result in systemic accumulation of glycosaminoglycans (GAGs). Accumulation of GAGs in the upper airway can lead to respiratory failure. The aim of this study was to investigate changes of the airway by flexible endoscopy and CT.

METHODS

Thirty-five patients aging from 2 to 16 years (mean: 9.2±4.4 years) participated in this study. The majority had MPS I (n=5) or MPS II (n=25). The shape of the trachea and the cross-sectional trachea surface area (TSA) was determined at the Th1 and Th2 levels. Airway obstruction was evaluated from endoscopic findings and classified into 3 grades (Grades 0, 1, and 2). Forty-five patients in the control group who underwent tracheal CT for other conditions were retrospectively selected from the database.

RESULTS

Tracheal morphology was abnormal in 50-60%, which showed a transversely collapsing narrow trachea. Tracheal deformity was severe in MPS II and MPS IV. The mean TSA of the MPS patients was 55.5±29.0 mm(2) at Th1 and 61.4±29.0 mm(2) at Th2, while that of the control group was 90.1±41.9 mm(2) and 87.9±39.3 mm(2), respectively. Respiratory distress was noted in 15 of the 35 patients, among whom 7 patients showed tracheal deformity and 7 patients had laryngeal redundancy. Three patients had no abnormalities of the larynx or trachea, so other factors such as pharyngeal stenosis or lower airway stenosis might have contributed to their respiratory distress.

CONCLUSION

CT and flexible endoscopy allow quantitative and morphological evaluation of airway narrowing, which is beneficial for airway management in MPS children.

Radiological and clinical characterization of the lysosomal storage disorders: non-lipid disorders

Lysosomal storage diseases (LSDs) are a large group of genetic metabolic disorders that result in the accumulation of abnormal material, such as mucopolysaccharides, glycoproteins, amino acids and lipids, within cells. Since many LSDs manifest during infancy or early childhood, with potentially devastating consequences if left untreated, timely identification is imperative to prevent irreversible damage and early death. In this review, the key imaging features of the non-lipid or extralipid LSDs are examined and correlated with salient clinical manifestations and genetic information. Disorders are stratified based on the type of excess material causing tissue or organ dysfunction, with descriptions of the mucopolysaccharidoses, mucolipidoses, alpha-mannosidosis, glycogen storage disorder II and cystinosis. In addition, similarities and differences in radiological findings between each of these LSDs are highlighted to facilitate further recognition. Given the rare and extensive nature of the LSDs, mastery of their multiple clinical and radiological traits may seem challenging. However, an understanding of the distinguishing imaging characteristics of LSDs and their clinical correlates may allow radiologists to play a key role in the early diagnosis of these progressive and potentially fatal disorders.

Respiratory and sleep disorders in mucopolysaccharidosis

MPS encompasses a group of rare lysosomal storage disorders that are associated with the accumulation of glycosaminoglycans (GAG) in organs and tissues. This accumulation can lead to the progressive development of a variety of clinical manifestations. Ear, nose, throat (ENT) and respiratory problems are very common in patients with MPS and are often among the first symptoms to appear. Typical features of MPS include upper and lower airway obstruction and restrictive pulmonary disease, which can lead to chronic rhinosinusitis or chronic ear infections, recurrent upper and lower respiratory tract infections, obstructive sleep apnoea, impaired exercise tolerance, and respiratory failure. This review provides a detailed overview of the ENT and respiratory manifestations that can occur in patients with MPS and discusses the issues related to their evaluation and management.

Anaesthesia and airway management in mucopolysaccharidosis

This paper provides a detailed overview and discussion of anaesthesia in patients with mucopolysaccharidosis (MPS), the evaluation of risk factors in these patients and their anaesthetic management, including emergency airway issues. MPS represents a group of rare lysosomal storage disorders associated with an array of clinical manifestations. The high prevalence of airway obstruction and restrictive pulmonary disease in combination with cardiovascular manifestations poses a high anaesthetic risk to these patients. Typical anaesthetic problems include airway obstruction after induction or extubation, intubation difficulties or failure [can't intubate, can't ventilate (CICV)], possible emergency tracheostomy and cardiovascular and cervical spine issues. Because of the high anaesthetic risk, the benefits of a procedure in patients with MPS should always be balanced against the associated risks. Therefore, careful evaluation of anaesthetic risk factors should be made before the procedure, involving evaluation of airways and cardiorespiratory and cervical spine problems. In addition, information on the specific type of MPS, prior history of anaesthesia, presence of cervical instability and range of motion of the temporomandibular joint are important and may be pivotal to prevent complications during anaesthesia. Knowledge of these risk factors allows the anaesthetist to anticipate potential problems that may arise during or after the procedure. Anaesthesia in MPS patients should be preferably done by an experienced (paediatric) anaesthetist, supported by a multidisciplinary team (ear, nose, throat surgeon and intensive care team), with access to all necessary equipment and support.

Mucopolysaccharidoses and the eye

The mucopolysaccharidoses (MPSs) are a group of disorders caused by inherited defects in lysosomal enzymes resulting in widespread intra- and extra-cellular accumulation of glycosaminoglycans. They have been subdivided according to enzyme defect and systemic manifestations and include MPS IH (Hurler), MPS IS (Scheie), MPS IH/S (Hurler/Sheie), MPS II (Hunter), MPS III (Sanfilippo), MPS IV (Morquio), MPS VI (Maroteaux-Lamy), MPS VII (Sly) and MPS IX (Natowicz). The mucopolysaccharidoses have a spectrum of systemic manifestations, including airway and respiratory compromise, skeletal deformities, intellectual and neurological impairment, cardiac abnormalities, and gastrointestinal problems. Ocular manifestations are common in the mucopolysaccharidoses and may result in significant visual impairment. Corneal opacification of varying severity is frequently seen, as well as retinopathy, optic nerve swelling and atrophy, ocular hypertension, and glaucoma. New treatment modalities for the systemic manifestations of the mucopolysaccharidoses include bone marrow transplant and enzyme replacement therapy, and have resulted in an improved prognosis in many cases. This article reviews the systemic and ocular manifestations of the mucopolysaccharidoses, as well as new treatment options, and discusses the ophthalmic management of mucopolysaccharidosis patients.

Upper airway diseases and airway management: a synopsis

This article summarizes some of the more important upper airway conditions likely to affect airway management. A number of upper airway conditions may present difficult challenges to the anesthesiologist. For instance, infected airway structures may lead to partial airway obstruction, stridor, or even complete airway obstruction. Partial airway obstruction may be mild, as in snoring or nasal congestion, or may be more severe, perhaps requiring the use of airway adjuncts, such as a nasopharyngeal airway. Complete airway obstruction is usually managed by prompt intubation, but surgical airways are sometimes needed as a last resort.

Disordered breathing during sleep in patients with mucopolysaccharidoses

OBJECTIVE

Obstructive sleep apnoea (OSA) has been reported as a feature of children with mucopolysaccharidoses (MPS). However, the incidence and severity of OSA with respect to disease type is poorly defined. The aim of the present study was to measure objectively the degree of OSA in a group of children with a range of MPS syndromes.

METHODS

In a cross-sectional study, cardiopulmonary sleep studies were performed during unsedated sleep in 26 children with MPS over a period of 2 years. Scores of OSA severity based upon clinical history and upon objective sleep study data were made in each case and compared.

RESULTS

OSA was present in 24/26 patients, and ranged in severity from mild to severe. OSA was most marked in MPS type IH (Hurler syndrome) followed by types IHS (Hurler--Scheie syndrome) and II (Hunter syndrome). Frequent arousals and poor sleep quality, not suspected clinically, were noted in several patients. There was agreement between the clinical and objective scoring systems in only 17/26 patients (65%) with clinical history scores tending to underestimate the most severe cases (5/26 cases) and overestimate the severity in the mild cases (4/26 cases).

CONCLUSIONS

Obstructive respiratory problems are frequent in MPS patients and there are differences in severity of OSA between the different MPS types. Assessments of the severity of OSA based upon clinical history alone are inadequate. Our results suggest that objective sleep studies are necessary to evaluate these cases, to monitor clinical outcome and to assess the effects of therapeutic intervention. Prospective studies in larger numbers of patients are needed to validate these observations.

Glossoptosis (posterior displacement of the tongue) during sleep: a frequent cause of sleep apnea in pediatric patients referred for dynamic sleep fluoroscopy

OBJECTIVE

The purpose of this study was to evaluate the frequency of glossoptosis (posterior displacement of the tongue) as a cause of sleep apnea in pediatric patients referred for fluoroscopic sleep studies.

MATERIALS AND METHODS

Seventy consecutive dynamic fluoroscopic sleep studies performed to evaluate sleep apnea were reviewed. All patients had been sedated and examined with lateral fluoroscopy during sleep. Anatomic changes in the airway were correlated with episodes of oxygen desaturation. Cases of glossoptosis, in which the tongue moved posteriorly during sleep and abutted the posterior pharynx, resulting in airway obstruction and oxygen desaturation, were identified. Associated factors were reviewed.

RESULTS

Of 70 sleep studies reviewed, glossoptosis was the cause of airway obstruction in 17 patients (24%). Mean age in these 17 patients was 3 years (range, 5 days to 13 years). Seven of the 17 children were younger than 1 year old. Only three patients had no underlying medical problems. Four patients had macroglossia (Down syndrome, n = 3; duplicated tongue, n = 1) as a cause, and three patients had micro- or retrognathia (Pierre Robin syndrome, n = 2; Rubinstein-Taybi syndrome, n =1) as a cause. Six patients had neuromuscular abnormalities.

CONCLUSION

Glossoptosis was a cause of airway obstruction in 25% of pediatric patients referred for fluoroscopic sleep studies. Attention to this anatomic region is important when evaluating children with sleep apnea.

Endoscopic adenoidectomy in a case of Scheie syndrome (MPS I S)

The mucopolysaccharidoses (MPS) are a heterogeneous group of relatively rare, progressive, inherited lysosomal storage disorders, characterized by a deficiency of lysosomal enzymes which are responsible for the stepwise degradation of glycosaminoglycans. Their deficiency leads to the accumulation of glycosaminoglycans in various organs causing progressive disruption of cellular functions and multiple systemic effects including otolaryngological problems, upper airway obstructive disease being the most common. Scheie syndrome (MPS I S) is due to the deficient activity of alpha-L-iduronidase leading to the intralysosomal accumulation of dermatan sulfate and heparan sulfate. We present our experience in one such case occuring in a 6-year-old girl with ENT manifestations and who underwent a successful endoscopic adenoidectomy for symptomatic adenoid hypertrophy. This procedure was preferred over a conventional adenoidectomy in order to avoid complications associated with abnormal cervical vertebrae.

Otologic and laryngologic manifestations of mucopolysaccharidoses after bone marrow transplantation

INTRODUCTION

Children with mucopolysaccharidosis have significant functional impairment of a number of systems because of deposition of glycosaminoglycans. The otolaryngologic system is affected, resulting in conductive and sensorineural hearing loss and voice abnormality.

METHOD

Eleven children who had undergone bone marrow transplantation had their hearing and voices assessed. Unmatched data from patients who had not undergone transplantation were collected for nonstatistical comparison.

RESULTS

The hearing loss in children who had undergone bone marrow transplantation was variable but on average was less severe than in the younger children who had not undergone transplantation. The incidence of otitis media with effusion was diminished in the transplanted group. Approximately half had normal voices.

DISCUSSION

Diminution of the progression of hearing loss and voice abnormality probably occurs in patients after treatment by bone marrow transplantation.

Sleep fluoroscopy for localization of upper airway obstruction in children

The management of children with upper airway obstruction (UAO) in whom previous airway surgeries or concomitant craniofacial or neuromuscular abnormalities exist is complicated by potential obstruction at multiple sites. Sleep fluoroscopy (SF) provides a dynamic representation of relative degrees of obstruction at multiple levels of the pediatric airway. Fifty-five SF studies were performed on 50 infants and children to localize obstructive sites. Correlation was assessed with findings on direct laryngoscopy and bronchoscopy under spontaneous ventilation. In 24 (44%), endoscopic and SF findings correlated exactly. The SF studies identified a site of UAO in 11 patients with normal findings on endoscopic examination and multiple sites of UAO in 16 others. Two thirds of these occurred at the hypopharynx and tongue base. The SF studies failed to detect 5 airway abnormalities in 4 patients. The sensitivity of SF for endoscopically verified laryngotracheal lesions was lowest for glottic (67%) and subglottic (70%) locations and higher for tracheal (92%) and supraglottic (100%) sites. Sleep fluoroscopy altered the course of treatment in 26 (52%) children. It appears to be a valuable adjunct to endoscopy in the identification and management of pediatric UAO when hypopharyngeal collapse or multiple levels of obstruction are suspected.