Anaesthesia and airway management in mucopolysaccharidosis

General anesthesia with a native airway for patients with mucopolysaccharidosis type III

BACKGROUND

Mucopolysaccharidosis type III is a progressive disease with worsening airway, pulmonary, and cardiac involvement that may complicate anesthetic care.

AIM

To prospectively evaluate the incidence of airway issues and complications during magnetic resonance imaging (MRI) and lumbar puncture (LP) during general anesthesia with a native airway for patients with mucopolysaccharidosis type III.

METHOD

The study was a part of the natural history study. Anesthesia was induced with sevoflurane, which was discontinued after intravenous access was obtained. General anesthesia with a native airway was provided by dexmedetomidine and propofol. Dexmedetomidine (0.5 μg·kg^-1 ) was administered over 5 min followed by a continuous infusion at 0.5 μg·kg^-1 ·h^-1 . A continuous infusion of propofol was started at 150 μg·kg^-1 ·min^-1 . A bolus dose of propofol (1 mg·kg^-1 ) was administered and the propofol infusion was increased as needed. Airway management and vital signs were recorded for the entire procedure until discharge.

RESULTS

Twenty-five patients (6.9 ± 3.1 years) received total of 43 MRI and LP procedures in the cohort. No patient failed sedation. Although mask induction with sevoflurane was not clinically problematic, upper airway obstruction was noted during 14 procedures (33%). This required the application of continuous positive airway pressure, temporary oral airway placement, jaw thrust, or shoulder roll. Airway dynamics improved once the anesthesia was transitioned to intravenous anesthetic agents. Although a small shoulder roll was needed to improve airway patency for 11 cases (26%), a large shoulder roll tended to make the upper airway obstruction worse. Oxygen desaturation (≤90%) was noted during MRI in three cases (7%).

CONCLUSION

A combination of dexmedetomidine and propofol provided effective general anesthesia with a native airway during the procedures. Although upper airway obstruction was noted, it resolved with simple airway maneuvers without further airway intervention.

Non-invasive pulmonary function test on Morquio patients

Morquio patients, in many cases, present with severe tracheal narrowing and restrictive lung problems making them susceptible to high mortality arising from sleep apnea and related complications. Tracheal obstruction with growth imbalance, short neck, adeno and tonsillar hypertrophy, large mandible, and/or pectus carinatum also contributes to the challenges in managing the airway with intubation and extubation due to factors intrinsic to Morquio syndrome. Taken together, these issues lead to serious respiratory distress and life-threatening complications during anesthetic procedures. Furthermore, patients with Morquio syndrome frequently cannot perform standard pulmonary function tests as a result of their distinctive skeletal dysplasia and chest deformity, thus making diagnosis of incipient pulmonary disease difficult. In many cases, conventional spirometry is too difficult for patients to complete, deriving from issues with cooperation or clinical circumstance. Therefore, it is an unmet challenge to assess pulmonary insufficiency with standard pulmonary function test (PFT) with minimal effort. Non-invasive PFT such as respiratory inductance plethysmography, impulse oscillometry system, and pneumotachography were described in Morquio patients as compared with spirometry. Findings from our previous study indicate that these non-invasive tests are a reliable approach to evaluate lung function in a larger range of patients, and provide valuable clinical information otherwise unobtainable from invasive tests. In conclusion, the present study describes the utility of non-invasive (PFT) to accommodate a broad range of patients including intolerance to effort-dependent PFT.

Impact of long-term elosulfase alfa treatment on respiratory function in patients with Morquio A syndrome

OBJECTIVE

To present long-term respiratory function outcomes from an open-label, multi-center, phase 3 extension study (MOR-005) of elosulfase alfa enzyme replacement therapy (ERT) in patients with Morquio A syndrome.

METHODS

In part 1 of MOR-005, patients initially randomized to ERT in the 24-week pivotal study (MOR-004) remained on their regimen (2.0 mg/kg/week or every other week); placebo patients were re-randomized to one of the two regimens. During part 2, all patients received elosulfase alfa 2.0 mg/kg/week. Respiratory function was one of the efficacy endpoints evaluated in MOR-005. Change from MOR-004 baseline to 120 weeks of treatment for the combined population was determined and compared with results from untreated patients from a Morquio A natural history study (MorCAP).

RESULTS

Maximum voluntary ventilation (MVV) improved up to week 72 and then stabilized; forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) increased continuously over 120 weeks. Mean increases in the modified per-protocol population was 9.2 % for FVC, 8.8 % for FEV₁, and 6.1 % for MVV after 120 weeks. All patients ≤14 years showed respiratory improvements, presumably in part related to growth; however, these were greater in treated patients. For those >14 years, treated patients showed improvements, while deterioration occurred in untreated. Altogether, the improvements were significantly greater (P < 0.05) in treated patients.

CONCLUSIONS

Long-term ERT is associated with sustained improvements in respiratory function in Morquio A. In younger patients (≤14 years), some improvement may be ascribed to growth. In older patients, other mechanisms, e.g., decreased glycosaminoglycan storage, are likely involved.

Anaesthetic Implications of the Changing Management of Patients with Mucopolysaccharidosis

The mucopolysaccharidoses are a group of inherited metabolic disorders that are renowned for presenting clinical problems, particularly related to cardiac, airway, and skeletal abnormalities, in children during anaesthesia. The changing clinical management of the mucopolysaccharidoses can be described in three phases. An initial phase of accumulation and dissemination of knowledge about the management of this rare disease with a growing recognition that untreated Hurler syndrome and more severe forms of other phenotypes such as Hunter syndrome and Maroteaux–Lamy syndrome were associated with severe complications under anaesthesia. This was followed by a second phase reflecting the beneficial results of new treatments such as haemopoietic stem cell transplantation and enzyme replacement therapy. Early and successful transplantation has dramatically improved long-term outcome and reduced anaesthetic complications in children with Hurler syndrome. Enzyme replacement therapy is available for many forms of mucopolysaccharidosis. If commenced at an early age improvement in many organ systems may be observed with an improved quality of life. However, these current treatment regimens do not appear to improve neurocognitive dysfunction, or cardiac valvular or skeletal abnormalities. We are now entering a third phase where the partial benefits of these treatment regimens are resulting in an increasing number of older patients with partially corrected abnormalities, including difficult airways, presenting for ongoing treatment to a new and potentially unsuspecting group of clinicians. Major airway abnormalities may be encountered and current adult guidelines may need to be adapted. A multidisciplinary team approach involving paediatric and adult anaesthetists is recommended to optimise future management.

Anaesthesia management in craniovertebral junctional anomalies

Craniovertebral Junctional (CVJ) anomalies are developmental disorders that affect the skeleton and enclosed neuraxis at the junction of cranium and cervical spine. The high prevalence of airway obstruction and restrictive pulmonary disease in combination with cardiovascular manifestations poses a high anaesthetic risk to these patients. This article provides a discussion of management of anaesthesia in patients with craniovertebral anomalies, the evaluation of risk factors in these patients and their management, including emergency airway issues.

Unique medical issues in adult patients with mucopolysaccharidoses

The mucopolysaccharidoses are a group of inherited metabolic diseases caused by deficiencies in enzymes involved in the sequential degradation of glycosaminoglycans (GAGs) leading to substrate accumulation in various tissues and organs. GAG accumulation can cause growth retardation and progressive damage to respiratory, cardiovascular, musculoskeletal, nervous, gastrointestinal, auditory, and visual systems. In the past, few people with severe phenotypic mucopolysaccharidosis (MPS) reached adulthood. However, better methods for diagnosis, multi-disciplinary care, and new therapies have extended lifespan, leading to an increasing number of patients surviving beyond childhood. The growing number of adult MPS patients poses significant challenges for clinicians who may not be familiar with the clinical manifestations of MPS. In addition, as new interventions have changed the natural history of these disorders, it is difficult to anticipate both the impact on life expectancy and other complications that may occur as these patients age. Because the MPS disorders are multi-organ diseases, their management requires a coordinated multi-disciplinary approach. Here we discuss the unique pattern of medical issues and multi-organ involvement in adult patients with MPS and identify the challenges that are associated with management of MPS. This review is based on information from an expert investigator meeting with MPS specialists held October 2-4, 2014 in Dublin, Ireland, as well as on current literature searches focusing on MPS and adults.

Pregnancy in patients with mucopolysaccharidosis: a case series

The mucopolysaccharidoses (MPS disorders) are rare inherited diseases associated with multi-organ accumulation of glycosaminoglycans, leading to musculoskeletal, respiratory, cardiac, neurological, ophthalmological, otolaryngological, and gastrointestinal abnormalities. As a result of improvements in diagnosis, multi-disciplinary care, and therapies such as enzyme replacement therapy and hematopoietic stem cell transplantation, an increasing number of patients with MPS are reaching adulthood and are involved in family planning. Data on fertility and pregnancy outcome in MPS is sparse and comprises primarily isolated case reports. To address this evidence gap, we present a case series on fertility and pregnancy in eight mothers and five fathers with MPS. This case series demonstrates that women with MPS have high-risk pregnancies and deliveries secondary to their underlying disease. However, with appropriate pre-conceptual multi-disciplinary evaluation, optimization and discussion regarding potential risks, combined with regular multi-disciplinary maternal and fetal surveillance in a tertiary center, the outcome of most pregnancies in this case series seems to be favorable with all babies developing normally. Partners of fathers with MPS had uncomplicated pregnancies and deliveries. All children were healthy, with normal growth and development.

Cervical cord compression in mucopolysaccharidosis VI (MPS VI): Findings from the MPS VI Clinical Surveillance Program (CSP)

OBJECTIVES

To gain insight into the frequency, age of onset, and management of cervical cord compression in mucopolysaccharidosis VI (MPS VI).

METHODS

Cervical spine magnetic resonance imaging (MRI) data and/or cervical decompression surgery data collected between 30 June 2005 and 1 September 2015 were analyzed from subjects enrolled in the MPS VI Clinical Surveillance Program (CSP) (ClinicalTrials.gov: NCT00214773), an ongoing multicenter, observational, retrospective and prospective registry.

RESULTS

Of 213 subjects enrolled in the CSP, 134 (62.9%) had at least one documented cervical spine MRI assessment. An additional four subjects were identified through surgery records alone to yield a study population comprising 138 subjects (mean age at enrollment =15.1years; age range=0.80-65.0years). Cervical cord compression was documented in 101 (75.4%) of the 134 subjects with ≥1 MRI assessment, the majority (95.0%) by the time of the first recorded MRI. In general, subjects with cervical cord compression had significantly lower height Z-scores compared to those without cervical cord compression (p<0.0001); nevertheless, a few subjects of taller stature had documented cervical cord compression at a young age. Most subjects >20years of age (31/33, 93.9%) presented with cervical cord compression. There was an insufficient number of subjects with both pre- and post-enzyme replacement therapy (ERT) MRI data to determine any association between ERT and cervical cord compression. Surgical decompression was performed on 58 subjects (42.0%), with mean age at first surgery of 13.1years. Decompression plus stabilization procedures accounted for 12.1% of surgeries. Eight subjects (13.8%) underwent reoperation. Complications during or following surgery were reported in 3 subjects, with anesthesia-related complications resulting in two deaths.

CONCLUSIONS

All individuals with MPS VI are at high risk of developing cervical cord compression at an early age. Routine MRI assessments should be initiated from the time of MPS VI diagnosis. The perioperative management of MPS VI patients can be challenging. This study contributes to the understanding of the natural history of MPS VI.

Current therapies for Morquio A syndrome and their clinical outcomes

INTRODUCTION

Morquio A syndrome is characterized by a unique skeletal dysplasia, leading to short neck and trunk, pectus carinatum, laxity of joints, kyphoscoliosis, and tracheal obstruction. Cervical spinal cord compression/inability, a restrictive and obstructive airway, and/or bone deformity and imbalance of growth, are life-threatening to Morquio A patients, leading to a high morbidity and mortality. It is critical to review the current therapeutic approaches with respect to their efficacy and limitations.

AREAS COVERED

Patients with progressive skeletal dysplasia often need to undergo orthopedic surgical interventions in the first two decades of life. Recently, we have treated four patients with a new surgery to correct progressive tracheal obstruction. Enzyme replacement therapy (ERT) has been approved clinically. Cell-based therapies such as hematopoietic stem cell therapy (HSCT) and gene therapy are typically one-time, permanent treatments for enzyme deficiencies. We report here on four Morquio A patients treated with HSCT approved in Japan and followed for at least ten years after treatment. Gene therapy is under investigation on mouse models but not yet available as a therapeutic option.

EXPERT OPINION

ERT and HSCT in combination with surgical intervention(s) are a therapeutic option for Morquio A; however, the approach for bone and cartilage lesion remains an unmet challenge.

Management of Life-Threatening Tracheal Stenosis and Tracheomalacia in Patients with Mucopolysaccharidoses

Several different lysosomal storage diseases, mainly mucopolysaccharidosis (MPS) type I, II, and VI, are complicated by severe obstruction of the upper airways, tracheobronchial malacia, and/or stenosis of the lower airways. Although enzyme replacement therapies (ERTs) are available, the impact of these on tracheobronchial alterations has not been reported. By extending the life expectancy of MPS patients with ERTs, airway problems may become more prevalent at advanced ages. These airway abnormalities can result in severe, potentially fatal, difficulties during anesthetic procedures. Usually, upper airway obstruction is treated by tracheostomy. However, with lower airway malacia and/or stenosis, there are no procedures available to date to address these difficulties. We report the first cases using a new technique of tracheal stenting in patients with MPS type VI (Maroteaux-Lamy syndrome) and type II (Hunter syndrome) who had almost complete tracheal occlusion and total airway collapse. An updated literature review is also reported.

Anesthetic care and perioperative complications in children with Sanfilipo Syndrome Type A

BACKGROUND

Patients with mucopolysaccharidoses (MPS) are generally considered high risk for anesthesia care, owing to disease-related factors. Sanfilippo syndrome type A (MPS IIIA) is the most frequently occurring MPS. Anesthesia-specific information for MPS IIIA is not readily available in the literature.

OBJECTIVES

To report post hoc analyses on anesthesia care and outcomes from a 2-year study of the natural history of patients with untreated MPS IIIA (NCT01047306).

METHODS

Subjects were ≥1 year of age, developmental age ≥1 year, and without significant central nervous system impairment (other than that due to MPS IIIA) or issues that would preclude study procedures. Procedures requiring general anesthesia included brain/abdominal magnetic resonance imaging, lumbar puncture, and echocardiography. Sedation, intubation, and extubation procedures as well as postoperative airway problems were recorded at baseline and 6, 12, and 24 months of age.

RESULTS

Twenty-five patients (baseline age, 13-220 months) received a total of 94 general anesthetics. Patients successfully received oral sedation prior to 76 of 94 anesthetics. No patients required airway intervention or oxygen supplementation during sedation. All anesthesia providers described facemask ventilation and endotracheal intubations as 'easy'. All subjects were successfully extubated after completion of the procedures. No patients required reintubation. Six (24%) patients had episodes of postoperative airway problems: wheezing (7/94, 7.4%), croup (6/94, 6.4%), and laryngospasm (2/94, 2.1%).

CONCLUSION

We found no change in the modified Cormack-Lehane intubation grades in 25 Sanfilippo syndrome type A children over the 2-year study period.

Tracheobronchial stents in mucopolysaccharidosis

INTRODUCTION

The mucopolysaccharidoses are a group of hereditary disorders pathologically characterized by tissue accumulation of glycosaminoglycans due to deficient lysosomal metabolism which often leads to progressive airway stenosis and respiratory insufficiency. Relentless and treatment-refractory narrowing of the lower airways with ensuing severe limitation of quality of life is a challenging problem in mucopolysaccharidoses.

CASE REPORTS

We report 2 cases of MPS (Hunter's and Maroteaux-Lamy's syndrome resp.) in whom tracheal stents were placed to relieve severe tracheal obstruction. The first patient could be weaned from mechanical ventilation after stent placement but showed significant long-term stent-related morbidity. The second patient suffered a severe procedure-related complication due to positioning problems typical for MPS.

CONCLUSIONS

Very good short-term success can be achieved with airway stent placement in patients with MPS and severe lower airway stenosis but a high risk of severe complications and important long-term morbidity have to be weighed against potential individual benefit.

Alterations of mucosa of the larynx and hypopharynx in patients with mucopolysaccharidoses

OBJECTIVE

This study aimed to: assess the mucosal alterations of the larynx and hypopharynx typical for mucopolysaccharidoses, in a standardised manner; compare the severity in different subtypes of mucopolysaccharidoses; and monitor the effect of an enzyme replacement therapy.

METHODS

A classification for mucosal alterations of the larynx and hypopharynx was developed and utilised in 55 patients with mucopolysaccharidoses. Fifteen patients who started treatment with enzyme replacement therapy were followed longitudinally.

RESULTS

The most severe alterations were seen in the posterior region of the larynx and the arytenoids, and in the region of the false vocal folds. The alterations were most severe in patients with mucopolysaccharidosis II. No clear trend was observed in the patients who received enzyme replacement therapy.

CONCLUSION

Quantification of mucosal alterations of the hypopharynx and larynx in mucopolysaccharidoses patients can provide information about the disease's natural process and about the efficacy of enzyme replacement therapy.

Sanfilippo syndrome: Overall review

Mucopolysaccharidosis type III (MPS III, Sanfilippo syndrome) is a lysosomal storage disorder, caused by a deficiency in one of the four enzymes involved in the catabolism of glycosaminoglycan heparan sulfate. It is characterized by progressive cognitive decline and severe hyperactivity, with relatively mild somatic features. This review focuses on clinical features, diagnosis, treatment, and follow-up of MPS III, and provides information about supplementary tests and differential diagnosis. Given that few reviews of MPS III have been published, several studies were compiled to establish diagnostic recommendations. Quantitative urinary glycosaminoglycan analysis is strongly recommended, and measurement of disaccharides, heparin cofactor II-thrombin complex and gangliosides is also used. Enzyme activity of the different enzymes in blood serum, leukocytes or fibroblasts, and mutational analysis for SGSH, NAGLU, HGSNAT or GNS genes are required to confirm diagnosis and differentiate four subtypes of MPS III. Although there is no global consensus for treatment, enzyme replacement therapy and gene therapy can provide appropriate results. In this regard, recent publications on treatment and follow-up are discussed.

International guidelines for the management and treatment of Morquio A syndrome

Morquio A syndrome (mucopolysaccharidosis IVA) is a lysosomal storage disorder associated with skeletal and joint abnormalities and significant non-skeletal manifestations including respiratory disease, spinal cord compression, cardiac disease, impaired vision, hearing loss, and dental problems. The clinical presentation, onset, severity and progression rate of clinical manifestations of Morquio A syndrome vary widely between patients. Because of the heterogeneous and progressive nature of the disease, the management of patients with Morquio A syndrome is challenging and requires a multidisciplinary approach, involving an array of specialists. The current paper presents international guidelines for the evaluation, treatment and symptom-based management of Morquio A syndrome. These guidelines were developed during two expert meetings by an international panel of specialists in pediatrics, genetics, orthopedics, pulmonology, cardiology, and anesthesia with extensive experience in managing Morquio A syndrome. © 2014 The Authors. American Journal of Medical Genetics Part A published by Wiley Periodicals, Inc.

Orthopedic management of the extremities in patients with Morquio A syndrome

BACKGROUND

Musculoskeletal involvement in Morquio A syndrome (mucopolysaccharidosis IVA; MPS IVA) contributes significantly to morbidity and mortality. While the spinal manifestations of the disorder have received considerable attention in the literature, there have been few reported studies to date to guide the management of the orthopedic problems associated with the lower and upper extremities.

PURPOSE

The objective was to develop recommendations for the management of the extremities in patients with Morquio A syndrome.

METHODS

A group of specialists in orthopedics, pediatrics and genetics with experience in the management of Morquio A patients convened to review and discuss current clinical practices and to develop preliminary recommendations. Evidence from the literature was retrieved. Recommendations were further refined until consensus was reached.

RESULTS AND CONCLUSIONS

This present article provides a detailed review and discussion of the lower and upper extremity deformities in Morquio A syndrome and presents recommendations for the assessment and treatment of these complications. Key issues, including the importance of early diagnosis and the implications of medical therapy, are also addressed. The recommendations herein represent an attempt to develop a uniform and practical approach to managing patients with Morquio A syndrome and improving their outcomes.

Treatment of lysosomal storage disorders: successes and challenges

Treatment options for a number of lysosomal storage disorders have rapidly expanded and currently include enzyme replacement therapy, substrate reduction, chaperone treatment, hematopoietic stem cell transplantation, and gene-therapy. Combination treatments are also explored. Most therapies are not curative but change the phenotypic expression of the disease. The effectiveness of treatment varies considerably between the different diseases, but also between sub-groups of patients with a specific lysosomal storage disorder. The heterogeneity of the patient populations complicates the prediction of benefits of therapy, specifically in patients with milder disease manifestations. In addition, there is a lack of data on the natural history of diseases and disease phenotypes. Initial trial data show benefits on relevant short-term endpoints, but the real world situation may reveal different outcomes. Collaborative international studies are much needed to study the long-term clinical efficacy of treatments, and to detect new complications or associated conditions of the diseases. This review summarizes the available treatment modalities for lysosomal storage disorders and the challenges associated with long term clinical care for these patients.

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.

Management of difficult airway with laryngeal mask in a child with mucopolysaccharidosis and mitral regurgitation: a case report

INTRODUCTION

Mucopolysaccharidoses (MPSs) are a group of heredity storage diseases, transmitted in an autosomal recessive manner, associated with the accumulation of glycosaminoglycans (GAGs) in various tissues and organs. The concerned patients have multiple concomitant hereditary anomalies. Considering the craniofacial abnormality in these patients, airway management may be difficult for anesthesiologists. In these patients, preanesthetic assessment is necessary and performed with the accurate assessment of airways, consisting of the physical exam and radiography, MRI or CT of head and neck. An anesthesiologist should set up a "difficult intubation set" with a flexible fiber-optic bronchoscope and also, it may be necessary to discuss with an ear-nose and throat (ENT) specialist if required, for unpredicted emergency situations.

CASE PRESENTATION

In this case-report we presented a 2-year-old boy with known MPSs with psychomotor retardation, bilateral corneal opacities, impaired hearing and vision, inguinal hernia, severe mitral regurgitation, micrognathia, coarse facial feature, stiff and short neck and restricted mouth opening. He scheduled for left inguinal hernia repair surgery.

DISCUSSION

The patient's difficult airway was managed successfully and the anesthesia of his surgical procedure had an uneventful course.

Mortality in patients with morquio syndrome a

BACKGROUND

Morquio syndrome A (mucopolysaccharidosis type IVA) is an autosomal recessive, life-limiting lysosomal storage disease characterized by deficient activity of the enzyme galactosamine-6-sulfatase. The disease affects multiple body systems, and patients require multidisciplinary care from an early age.

METHODS

To better understand the natural progression of the disease, life expectancy and common causes of death, death certificates were evaluated for 27 patients (15 male, 12 female) with Morquio syndrome A in the UK, covering the years 1975-2010.

RESULTS

Mean age at death (±standard deviation) was 25.30 ± 17.43 years, with female patients living longer than male patients (26.55 ± 12.28 years versus 22.95 ± 17.63 years, respectively). Respiratory failure was the primary cause of death in nearly two-thirds of patients (63%). Other causes of death were cardiac failure (11%), post-traumatic organ failure (11%), complications of surgery (11%) and myocardial infarction (4%). Life expectancy increased gradually over time (R (2) = 0.0963), and mean age at death due to respiratory failure improved from 17.42 ± 9.54 years in the 1980s to 30.74 ± 10.84 years in the 2000s.

CONCLUSIONS

The current data suggest that survival of patients with Morquio syndrome A in the UK has improved in recent decades. It is possible that improvements in multidisciplinary care and referral of patients to specialist centres underlie this trend. It is hoped that novel disease-specific treatments such as enzyme replacement therapy and haematopoietic stem cell therapy will help to extend the lifespan of patients with Morquio syndrome further still.

Deep anterior lamellar keratoplasty in case of Hurler-Scheie syndrome

A 12-year-old boy with Hurler-Scheie syndrome (H/S syndrome) reported with reduced vision in both the eyes for past few years. Deep anterior lamellar keratoplasty (DALK) was performed for visual rehabilitation in his left eye. During surgery, the predescemet's plane was reached by meticulously dissecting the lamellar fibres using a manual technique. Histopathology of the dissected cornea showed the presence of numerous alcian blue positive deposits corroborating with the diagnosis of mucopolysaccharidosis (MPS). Postoperative course was uneventful. One year following surgery, the graft was clear and had a visual acuity of 20/50 with +1.00 170° - 0.75 refractive correction. Endothelial cell count, as measured by non-contact specular microscopy, was 2473.4 cells/mm(2). This case report highlights the application of DALK in a case of MPS-related corneal stromal opacification.

Surgical management of thoracolumbar kyphosis in mucopolysaccharidosis type 1 in a reference center

PURPOSE

Mucopolysaccharidosis (MPS) I is a rare autosomal recessive lysosomal storage disease. Thoracolumbar kyphosis is an early characteristic feature of the disease. Ossification failure in the anterosuperior quadrant of the vertebral body results in anterior dislocation. This study describes the surgical management of thoracolumbar kyphosis in MPS IH (Hurler syndrome) in a national reference center.

METHODS

Among 72 MPS I patients followed in our institution, we treated surgically 14 MPS IH patients with severe thoracolumbar kyphosis. The decision was made after documented deformity progression. Mean age at surgery was 8 (3.5-15) years. Sagittal imbalance of the trunk was constant. One patient underwent extended fusion for associated scoliosis. We retrospectively reviewed 13 patients who underwent selective circumferential fusion at the thoracolumbar level.

RESULTS

Average preoperative kyphosis was +57.5°(+30°; +90°). Surgical correction of the kyphosis was about 66 % and maintained at final follow-up. Fusion was obtained in all patients. Two patients required revision surgery consecutively to a previous posterior-only fusion, as a significant loss of correction occurred. One patient presented delayed neurologic deficit secondarily to cardiac embolism. One patient died postoperatively from cardiorespiratory failure.

CONCLUSION

Surgery is necessary when kyphosis is progressive despite orthopedic management, aggravating the multifactorial trunk imbalance. Regarding our experience, circumferential arthrodesis should be recommended to achieve stable correction. Surgical management requires a multidisciplinary approach due to multisystemic failure and neurological risks specific to metabolic disorders.

An update on ocular involvement in mucopolysaccharidoses

PURPOSE OF REVIEW

The purpose of this review is to provide an update on ocular manifestations of mucopolysaccharidoses (MPS), to highlight diagnostic pitfalls in the evaluation of affected patients, and to briefly review etiopathogenesis, systemic manifestations, and therapeutic interventions in MPS.

RECENT FINDINGS

Advances in hematopoietic stem cell transplantation and enzyme replacement therapy for MPS have led to decreased morbidity and increased life-span of patients. Besides other causes, visual impairment because of corneal opacification, retinal degeneration, and optic atrophy remains a common cause of disability in MPS. The application of a standard ophthalmic evaluation protocol may serve as an important diagnostic and disease monitoring tool in patients.

SUMMARY

Diagnostic delays are not uncommon in patients with MPS. Given the early ocular involvement in MPS, ophthalmologists play a crucial role in early detection and follow-up of patients with MPS. Ophthalmic evaluation can be impeded by corneal opacification and patient cooperation. Altered corneal biomechanics confound intraocular pressure measurements. Recently developed therapies have made early detection increasingly important. Accurate diagnosis of specific MPS subtypes is of paramount importance for initiating appropriate therapy. Combined with advances in supportive care of ocular and systemic manifestations, the prognosis for patients with MPS has vastly improved.

Treatment of hip dysplasia in patients with mucopolysaccharidosis type I after hematopoietic stem cell transplantation: results of an international consensus procedure

Background

Mucopolysaccharidosis type I (MPS-I) is a lysosomal storage disorder characterized by progressive multi-organ disease. The standard of care for patients with the severe phenotype (Hurler syndrome, MPS I-H) is early hematopoietic stem cell transplantation (HSCT). However, skeletal disease, including hip dysplasia, is almost invariably present in MPS I-H, and appears to be particularly unresponsive to HSCT. Hip dysplasia may lead to pain and loss of ambulation, at least in a subset of patients, if left untreated. However, there is a lack of evidence to guide the development of clinical guidelines for the follow-up and treatment of hip dysplasia in patients with MPS I-H. Therefore, an international Delphi consensus procedure was initiated to construct consensus-based clinical practice guidelines in the absence of available evidence.

Methods

A literature review was conducted, and publications were graded according to their level of evidence. For the development of consensus guidelines, eight metabolic pediatricians and nine orthopedic surgeons with experience in the care of MPS I patients were invited to participate. Eleven case histories were assessed in two written rounds. For each case, the experts were asked if they would perform surgery, and they were asked to provide information on the aspects deemed essential or complicating in the decision-making process. In a subsequent face-to-face meeting, the results were presented and discussed. Draft consensus statements were discussed and adjusted until consensus was reached.

Results

Consensus was reached on seven statements. The panel concluded that early corrective surgery for MPS I-H patients with hip dysplasia should be considered. However, there was no full consensus as to whether such a procedure should be offered to all patients with hip dysplasia to prevent complications or whether a more conservative approach with surgical intervention only in those patients who develop clinically relevant symptoms due to the hip dysplasia is warranted.

Conclusions

This international consensus procedure led to the construction of clinical practice guidelines for hip dysplasia in transplanted MPS I-H patients. Early corrective surgery should be considered, but further research is needed to establish its efficacy and role in the treatment of hip dysplasia as seen in MPS I.

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.