Mucopolysaccharidosis type I (Hurler syndrome) and anesthesia: the impact of bone marrow transplantation, enzyme replacement therapy, and fiberoptic intubation on airway management

Ameloblastoma in a Three-Year-Old Child with Hurler Syndrome (Mucopolysaccharidosis Type I)

Mucopolysaccharidoses (MPS) are a family of genetic diseases associated with a deficiency of alpha-L iduronidase, which causes a lack of catabolism of glycosaminoglycans (GAGs). Therefore, the accumulation of GAGs determines a wide spectrum of symptoms, typically found in a few syndromes like Hurler syndrome (HS). Among other specific manifestations, craniofacial abnormalities are crucial for the characterization of this syndrome. Ameloblastoma is a rare, benign, slow-growing, odontogenic tumor usually located in the mandible. Clear risk factors for the development of ameloblastoma remain unknown, but black patients have a fivefold increased risk. Clinically, it is characterized by a painless, variable-sized jaw swelling. Although classified as a benign tumor, ameloblastoma often has a severe clinical outcome. The most common type of ameloblastoma is the solid/multicystic/conventional one. A computed tomography scan (CT) with and without contrast is the gold standard for evaluating this kind of neoplasia. Conservative or radical surgery is the mainstay of treatment. In this case report, we described an unusual clinical assessment of conventional ameloblastoma interesting the posterior left mandible of a 35-month-old child affected by HS. This case represented a suggestive challenge both from a diagnostic and a therapeutic point of view. The patient was disease-free at 2 years’ follow-up.

Disease Manifestations in Mucopolysaccharidoses and Their Impact on Anaesthesia-Related Complications-A Retrospective Analysis of 99 Patients

Patients with mucopolysaccharidoses (MPS) frequently require anaesthesia for diagnostic or surgical interventions and thereby experience high morbidity. This study aimed to develop a multivariable prediction model for anaesthesia-related complications in MPS. This two-centred study was performed by retrospective chart review of children and adults with MPS undergoing anaesthesia from 2002 until 2018. We retrieved the patients’ demographics, medical history, clinical manifestations, and indication by each anaesthesia. Multivariable mixed-effects logistic regression was calculated for a clinical model based on preoperative predictors preselected by lasso regression and another model based on disease subtypes only. Of the 484 anaesthesia cases in 99 patients, 22.7% experienced at least one adverse event. The clinical model resulted in a better forecast performance than the subtype-model (AICc 460.4 vs. 467.7). The most relevant predictors were hepatosplenomegaly (OR 3.10, CI 1.54–6.26), immobility (OR 3.80, CI 0.98–14.73), and planned major surgery (OR 6.64, CI 2.25–19.55), while disease-specific therapies, i.e., haematopoietic stem cell transplantation (OR 0.45, CI 0.20–1.03), produced a protective effect. Anaesthetic complications can best be predicted by surrogates for advanced disease stages and protective therapeutic factors. Further model validation in different cohorts is needed.

Airway Abnormalities in Adult Mucopolysaccharidosis and Development of Salford Mucopolysaccharidosis Airway Score

(1) Background: Mucopolysaccharidoses (MPS) are a heterogeneous group of lysosomal storage disorders caused by the absence of enzymes required for degradation of glycosaminoglycans (GAGs). GAGs deposition in tissues leads to progressive airway narrowing and/or tortuosity. Increased longevity of patients has posed newer problems, especially the airway. This study aims to characterise various airway abnormalities in adult MPS from a regional centre and proposes a method to quantify the severity of the airway disease. (2) Methods: Retrospective analysis by case notes review, clinical examination, endoscopy, cross-sectional imaging, 3-dimensional reconstruction, and physiological investigations were used to assess the airway abnormalities. Quantitative assessment of the airway severity was performed a validated questionnaire of 15 parameters to derive Salford Mucopolysaccharidosis Airway Score (SMAS). (3) Results: Thirty-one adult MPS patients (21M/ 9F; median 26.7 years; range 19–42 years) were reviewed. There were 9 MPS I, 12 MPS II, 2 MPS III, 5 MPS IV, 2 MPS VI, and 1 MPS VII. Airway abnormalities in each MPS type are described. Patients scoring more than 35 on SMAS had some form of airway intervention. The area under curve of 0.9 was noted at a score of 25, so SMAS more than 25 may predict a difficult airway and potential to have complications. Pearson’s correlation between SMAS and height, weight, BMI were poor (p < 0.05). (4) Conclusions: Airway abnormalities in adult MPS are varied and complex. Assessment of the airway should be holistic and include multiple parameters. An objective multidimensional score such as SMAS may help to predict and manage difficult airways warranting further investigation and validation.

Mucopolysaccharidosis Type I: Current Treatments, Limitations, and Prospects for Improvement

Mucopolysaccharidosis type I (MPS I) is a lysosomal disease, caused by a deficiency of the enzyme alpha-L-iduronidase (IDUA). IDUA catalyzes the degradation of the glycosaminoglycans dermatan and heparan sulfate (DS and HS, respectively). Lack of the enzyme leads to pathologic accumulation of undegraded HS and DS with subsequent disease manifestations in multiple organs. The disease can be divided into severe (Hurler syndrome) and attenuated (Hurler-Scheie, Scheie) forms. Currently approved treatments consist of enzyme replacement therapy (ERT) and/or hematopoietic stem cell transplantation (HSCT). Patients with attenuated disease are often treated with ERT alone, while the recommended therapy for patients with Hurler syndrome consists of HSCT. While these treatments significantly improve disease manifestations and prolong life, a considerable burden of disease remains. Notably, treatment can partially prevent, but not significantly improve, clinical manifestations, necessitating early diagnosis of disease and commencement of treatment. This review discusses these standard therapies and their impact on common disease manifestations in patients with MPS I. Where relevant, results of animal models of MPS I will be included. Finally, we highlight alternative and emerging treatments for the most common disease manifestations.

Advanced Techniques for Securing Airway in Mucopolysaccharidoses and the Impact of New Therapeutic Approaches

Airway management in patients suffering from mucopolysaccharidoses (MPS) is one of the most difficult anesthesiologic challenges. MPS is a group of rare, inherited diseases caused by the absence or malfunctioning of lysosomal enzymes needed to break down macromolecules called glycosaminoglycans (GAGs). MPS is associated with clinical symptoms and physical features, which all together contribute to the high incidence of difficulty in providing airway during surgical procedures. We used PubMed as our main database (PubMed Advanced Search Builder) to search for relevant literature. At first, we looked for the prevalence of MPS worldwide. Then, we searched for airway management complications in the MPS population using the keywords: “Mucopolysaccharidoses,” “Anesthesia complications,” and “airway management.” Another search was carried out to look for new therapeutic agents and explore their impacts on body organs. We reviewed the finalized articles to explore how anesthesiologists used different airway techniques. We discovered that video laryngoscope and I-gel aided fiber-optic intubation have been available in recent years and have been used uneventfully in several patients. We presented recommendations regarding preoperative and intraoperative preparation to avoid airway-related complications in the future. We realized that many therapy approaches had been suggested, especially after further understanding of the pathophysiology of MPS. However, more investigation needs to be conducted to determine their efficacy and explore if there is any impact on airway management.

Mucopolysaccharidosis Type I: A Review of the Natural History and Molecular Pathology

Mucopolysaccharidosis type I (MPS I) is a rare autosomal recessive inherited disease, caused by deficiency of the enzyme α-L-iduronidase, resulting in accumulation of the glycosaminoglycans (GAGs) dermatan and heparan sulfate in organs and tissues. If untreated, patients with the severe phenotype die within the first decade of life. Early diagnosis is crucial to prevent the development of fatal disease manifestations, prominently cardiac and respiratory disease, as well as cognitive impairment. However, the initial symptoms are nonspecific and impede early diagnosis. This review discusses common phenotypic manifestations in the order in which they develop. Similarities and differences in the three animal models for MPS I are highlighted. Earliest symptoms, which present during the first 6 months of life, include hernias, coarse facial features, recurrent rhinitis and/or upper airway obstructions in the absence of infection, and thoracolumbar kyphosis. During the next 6 months, loss of hearing, corneal clouding, and further musculoskeletal dysplasias develop. Finally, late manifestations including lower airway obstructions and cognitive decline emerge. Cardiac symptoms are common in MPS I and can develop in infancy. The underlying pathogenesis is in the intra- and extracellular accumulation of partially degraded GAGs and infiltration of cells with enlarged lysosomes causing tissue expansion and bone deformities. These interfere with the proper arrangement of collagen fibrils, disrupt nerve fibers, and cause devastating secondary pathophysiological cascades including inflammation, oxidative stress, and other disruptions to intracellular and extracellular homeostasis. A greater understanding of the natural history of MPS I will allow early diagnosis and timely management of the disease facilitating better treatment outcomes.

Intravenous Enzyme Replacement Therapy in Mucopolysaccharidoses: Clinical Effectiveness and Limitations

The aim of this review is to summarize the evidence on efficacy, effectiveness and safety of intravenous enzyme replacement therapy (ERT) available for mucopolysaccharidoses (MPSs) I, II, IVA, VI and VII, gained in phase III clinical trials and in observational post-approval studies. Post-marketing data are sometimes conflicting or controversial, possibly depending on disease severity, differently involved organs, age at starting treatment, and development of anti-drug antibodies (ADAs). There is general agreement that ERT is effective in reducing urinary glycosaminoglycans and liver and spleen volume, while heart and joints outcomes are variable in different studies. Effectiveness on cardiac valves, trachea and bronchi, hearing and eyes is definitely poor, probably due to limited penetration in the specific tissues. ERT does not cross the blood–brain barrier, with the consequence that the central nervous system is not cured by intravenously injected ERT. All patients develop ADAs but their role in ERT tolerance and effectiveness has not been well defined yet. Lack of reliable biomarkers contributes to the uncertainties about effectiveness. The data obtained from affected siblings strongly indicates the need of neonatal screening for treatable MPSs. Currently, other treatments are under evaluation and will surely help improve the prognosis of MPS patients.

Airway management and perioperative adverse events in children with mucopolysaccharidoses and mucolipidoses: A retrospective cohort study

BACKGROUND

Children suffering from mucopolysaccharidoses (subtypes I, II, III, IV, VI, and VII) or mucolipidoses often require anesthesia, but are at high risk for perioperative adverse events. However, the impact of the disease subtype and the standard of care for airway management are still unclear.

AIMS

This study aimed to assess independent risk factors for perioperative adverse events in individuals with mucopolysaccharidoses/mucolipidoses and to analyze the interaction with the primary airway technique implemented.

METHODS

This retrospective study included individuals with mucopolysaccharidoses/mucolipidoses who underwent anesthesia at two high-volume centers from 2002 to 2016. The data were analyzed in a multivariate hierarchical model, accounting for repeated anesthesia procedures within the same patient and for multiple events within a single anesthesia.

RESULTS

Of 141 identified inpatients, 67 (63 mucopolysaccharidoses and 4 mucolipidoses) underwent 269 anesthesia procedures (study cases) for 353 surgical or diagnostic interventions. At least one perioperative adverse event occurred in 25.6% of the cases. The risk for perioperative adverse events was higher in mucopolysaccharidoses type I (OR 8.0 [1.5-42.7]; P = .014) or type II (OR 8.8 [1.3-58.6]; P = .025) than in type III. Fiberoptic intubation through a supraglottic airway was associated with the lowest risk for perioperative adverse events and lowest conversion rate. Direct laryngoscopy was associated with a significantly higher risk for airway management problems than indirect techniques (estimated event rates 47.8% vs 10.1%, OR 24.05 [5.20-111.24]; P < .001). The risk for respiratory adverse events was significantly higher for supraglottic airway (22.6%; OR 31.53 [2.79-355.88]; P = .001) and direct laryngoscopy (14.8%; OR 14.70 [1.32-163.44]; P = .029) than for fiberoptic intubation through a supraglottic airway (2.1%).

CONCLUSIONS

The disease subtype and primary airway technique were the most important independent risk factors for perioperative adverse events. Our findings indicate that in MPS/ML children with predicted difficult airway indirect techniques should be favored for the first tracheal intubation attempt.

Airway management in patients with mucopolysaccharidoses: The progression toward difficult intubation

BACKGROUND

Patients with mucopolysaccharidoses (MPS) have physical changes to their airways over time. Due to the natural progression of their disease, these patients become more difficult to intubate as they get older.

AIMS

The aims of this study were to evaluate the difficulty of airway management in MPS patients over time, and to evaluate the effect of bone marrow transplant and/or enzyme replacement therapy on airway difficulty.

METHODS

A retrospective review of MPS patients presenting for surgery from January 2012 to May 2018 was performed. Patients were assigned to groups based on their ages at the time of surgery, number of intubation attempts, equipment used for intubation, difficulty of mask ventilation, and difficulty of laryngeal mask airway placement. The same designations were applied to patients with a history of a bone marrow transplant (BMT) and/or enzyme replacement therapy, and they were compared to patients of similar ages who had received no treatment. Logistic regression was used to determine the odds of difficult intubation.

RESULTS

One hundred and twenty-eight anesthetic records were reviewed. In 27 cases, the patient had a BMT and in 54 cases, the patient had received enzyme replacement therapy. Adults (18 years and older) had the highest likelihood of difficult intubation (OR 13.44, CI 1.45-124.86, P = 0.022). Mask ventilation and laryngeal mask airway placement were not significantly more difficult in any age groups. Bone marrow transplant did not improve airway management. A history of enzyme replacement therapy was associated with an increased risk of difficult intubation in patients under the age of 12.

CONCLUSIONS

As patients with MPS get older, there is a progression toward difficult intubation. Mask ventilation and laryngeal mask airway placement does not become more difficult with age. Bone marrow transplantation did not affect airway difficulty in our population, while enzyme replacement therapy was associated with difficult intubations in younger patients.

Hematopoietic Stem Cell Transplantation for Mucopolysaccharidoses: Past, Present, and Future

Allogenic hematopoietic stem cell transplantation (HSCT) has proven to be a viable treatment option for a selected group of patients with mucopolysaccharidoses (MPS), including those with MPS types I, II, IVA, VI, and VII. Early diagnosis and timely referral to an expert in MPS are critical, followed by a complete examination and evaluation by a multidisciplinary team, including a transplantation physician. Treatment recommendations for MPS are based on multiple biological, sociological, and financial factors, including type of MPS, clinical severity, prognosis, present clinical signs and symptoms (disease stage), age at onset, rate of progression, family factors and expectations, financial burden, feasibility, availability, risks and benefits of available therapies such as HSCT, enzyme replacement therapy (ERT), surgical interventions, and other supportive care. International collaboration and data review are critical to evaluating the therapeutic efficacy and adverse effects of HSCT for MPS. Collaborative efforts to assess HSCT for MPS have been ongoing since the first attempt at HSCT in a patient with MPS reported in 1981. The accumulation of data since then has made it possible to identify early outcomes (ie, transplantation outcomes) and long-term disease-specific outcomes resulting from HSCT. The recent identification of predictive factors and the development of innovative regimens have significantly improved the outcomes of both engraftment failure and transplantation-related mortality. Assessment of long-term outcomes has considered a variety of factors, including type of MPS, type of graft, age at transplantation, and stage of disease progression, among others. Studies on long-term outcomes are considered a key factor in the use of HSCT in patients with MPS. These studies have shown the effects and limitations of HSCT on improving disease manifestations and quality of life. In this review, we summarize the efficacy, side effects, risks, and cost of HSCT for each type of MPS.

Anesthesiological risks in mucopolysaccharidoses

Background

Patients suffering from mucopolysaccharidosis are among the most complex from the anesthesiological point of view, especially regarding the management of the airway. The evidence base for anesthesia management is often limited to case reports and small case series.

Aims

To identify useful information about experience with each subtype of mucopolysaccharidosis reported in the literature and propose a guide on the best options for airway management to the anesthesiologists who take care of these patients.

Methods

A query of the PubMed database specific for “anesthesia” and “mucopolysaccharidosis” and a further query specific for “mucopolysaccharidosis and difficult airway management” was conducted. We looked for those items that offered practical guidance to anesthesiological management. We did not exclude case reports, especially those that reported a specific technique, because of their practical suggestions.

Results

We identified 15 reviews, 17 retrospective case series, 5 prospective studies, and 28 case reports that focused on airway managements in anesthesia or had practical suggestions for preoperative evaluation and risk assessment. An accurate preoperative evaluation and the need for an experienced team are emphasized in all the reviewed articles and for each type of mucopolysaccharidosis. Many suggestions on how to plan the perioperative period have been highlighted. Insertion of a laryngeal mask airway generally improves ventilation and facilitates intubation with a fiberoptic bronchoscope. Furthermore, the videolaryngoscope is very useful in making intubation easier and facilitating bronchoscope passage.

Conclusions

Patients with mucopolysaccharidosis are at high risk for anesthesia-related complications and require a high level of attention. However, a multidisciplinary approach, combined with expertise in the use of new techniques and new devices for airway management, makes anesthesiological management safer. Further research with prospective studies would be useful.

Electronic supplementary material

The online version of this article (10.1186/s13052-018-0554-1) contains supplementary material, which is available to authorized users.

Substrate accumulation and extracellular matrix remodelling promote persistent upper airway disease in mucopolysaccharidosis patients on enzyme replacement therapy

Introduction

Mucopolysaccharide diseases are a group of lysosomal storage disorders caused by deficiencies of hydrolase enzymes, leading to pathological glycosaminoglycan accumulation. A number of mucopolysaccharidosis (MPS) types are characterised by severe airway disease, the aetiology of which is poorly understood. There is ongoing evidence of significant clinical disease in the long-term despite disease modifying therapeutic strategies, including enzyme-replacement therapy (ERT). To provide a better understanding of this aspect of disease, we have characterised extracellular matrix (ECM) and inflammatory alterations in adenotonsillar tissue samples from 8 MPS patients.

Methods

Adenotonsillar samples from MPS I, IVA and VI ERT treated patients and from a single enzyme naïve MPS IIIA individual were compared to non-affected control samples using quantitative immunohistochemistry, qPCR and biochemical analysis.

Results

Significantly increased lysosomal compartment size and total sulphated glycosaminoglycan (p = 0.0007, 0.02) were identified in patient samples despite ERT. Heparan sulphate glycosaminoglycan was significantly elevated in MPS I and IIIA (p = 0.002), confirming incomplete reversal of disease. Collagen IV and laminin α-5 (p = 0.002, 0.0004) staining demonstrated increased ECM deposition within the reticular and capillary network of MPS samples. No significant change in the expression of the pro-inflammatory cytokines IL-1α, IL-6 or TNF-α was seen compared to control.

Conclusion

This study suggests a role for ECM remodelling contributing to the obstructive phenotype of airway disease in MPS. Current therapeutic strategies with ERT fail to normalise these pathological alterations within adenotonsillar samples. Our findings lend novel insight into the pathological cascade of events, with primarily structural rather than inflammatory changes contributing to the continuing phenotype seen in patients despite current therapeutic regimes.

Spinal cord issues in adult patients with MPS: transition of care survey

PURPOSE

This study aims to raise awareness of the need for research and appropriate guidelines for managing spinal cord issues in adult patients with mucopolysaccharidosis (MPS) and transition of these patients from pediatric to adult care.

METHODS

Pediatric/adult neurosurgeons, orthopedic spine surgeons, and treating physicians with expertise in metabolic disorders and spinal cord issues were invited to complete a survey to assess their experience with spinal cord problems in MPS and their opinion on transitioning routes from pediatric to adult care.

RESULTS

Twenty specialists completed the survey; 16 had treated spinal cord issues in patients with MPS. Foramen magnum and cervical stenosis (87%), atlanto-axial instability (67%), and lumbar spine instability (33%) were the main spinal cord issues encountered; 28% had treated adult patients for one or more spinal cord issues. In 40% of cases, this concerned an intervention or procedures performed during childhood. The main specialist responsible for the care of adult patients with MPS differed considerably between institutions and included both pediatric and adult specialists (30% pediatric neurosurgeons, 10% pediatric spine orthopedic surgeons, 30% adult spine neurosurgeons, 20% general adult surgeons). The preferred option (> 50%) for the transition of care was an interdisciplinary team of pediatric and adult specialists.

CONCLUSIONS

Further work needs to be done to address problems of managing spinal cord issues in adult patients with MPS. Currently, the responsibility for the care of patients with MPS with spinal cord issues is inconsistent. The best strategy for transitioning these patients from pediatric to adult care is likely an interdisciplinary approach.

Safety of anesthesia for children with mucopolysaccharidoses: A retrospective analysis of 54 patients

BACKGROUND

Complications are common during anesthesia for patients with mucopolysaccharidoses. San Gerardo Hospital (Italy) is a reference center for mucopolysaccharidoses with a dedicated pediatric anesthesia service.

AIMS

This study aims to evaluate the safety of anesthesia for mucopolysaccharidoses patients, describe their anesthetic management at our institution, and assess risk factors for complications.

METHODS

The anesthetic charts of mucopolysaccharidoses patients admitted from January 1999 to December 2014 were retrospectively analyzed. We retrieved patients' demographics; location and type of the procedure; anesthetic approach airway management and occurrence of difficult intubation and complications and outcome at hospital discharge. A generalized linear mixed model was performed to assess risk factors for complications and difficult intubation.

RESULTS

Fifty-four consecutive children were included. The anesthetic charts of 232 procedures (52% radio-diagnostics, 15% orthopedics, 15% ear-nose-throat surgery, 10% neurosurgery, and 8% general surgery) were analyzed. Each patient underwent a median of 4 (1-6) procedures. The median age at the first procedure was 2 (1-5), and overall age was 5 (2-8) years old. One hundred and twenty-five (54%) procedures were performed in remote locations. General anesthesia was utilized for 100 (43%) procedures. No death was recorded. Twenty-one (9%) procedures had respiratory complications. Remote location anesthesia was associated with increased risk for complications (odds ratio 5.405 [1.355-28.571], P = .016). All planned intubations (n = 65) were successful. Nineteen (29%) of those were defined difficult. All emergency intubations (n = 3) failed and were rescued by laryngeal mask airways. Older age was associated with an increased risk of difficult intubation (OR 1.200 [1.019-1.436], P = .028).

CONCLUSION

Patients with mucopolysaccharidoses are at high risk for anesthesia-related complications. Remote location anesthesia is associated with increased risk for complications, and older age is associated with increased risk for difficult intubation.

The mucopolysaccharidoses: advances in medical care lead to challenges in orthopaedic surgical care

The mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage disorders with clinical manifestations relevant to the orthopaedic surgeon. Our aim was to review the recent advances in their management and the implications for surgical practice. The current literature about MPSs is summarised, emphasising orthopaedic complications and their management. Recent advances in the diagnosis and management of MPSs include the recognition of slowly progressive, late presenting subtypes, developments in life-prolonging systemic treatment and potentially new indications for surgical treatment. The outcomes of surgery in these patients are not yet validated and some procedures have a high rate of complications which differ from those in patients who do not have a MPS. The diagnosis of a MPS should be considered in adolescents or young adults with a previously unrecognised dysplasia of the hip. Surgeons treating patients with a MPS should report their experience and studies should include the assessment of function and quality of life to guide treatment. Cite this article: Bone Joint J 2017;99-B:1132-9.

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.

Emergency bronchoscopy for foreign-body aspiration in a child with type I mucopolysaccharidosis: a challenging airway management experience

The mucopolysaccharidosis (MPS) is a rare lysosomal storage disease. Glycosaminoglycans (GAG) accumulate in musculoskeletal system, connective tissues. Enlarged tongue, short immobile neck, and limited mobility of the cervical spine and temporomandibular joints render the airway management potentially risky. MPS children have high anesthetic risks, especially in airway management of emergency situations. The foreign-body aspiration requiring intervention with rigid bronchoscopy is an urgent and risky clinical situation. We present our experience with a challenging airway management with a three-year-old child with MPS who needed emergency bronchoscopy due to peanut aspiration.

Sleep disordered breathing in mucopolysaccharidosis I: a multivariate analysis of patient, therapeutic and metabolic correlators modifying long term clinical outcome

Background

The lysosomal storage disorder, mucopolysaccharidosis I (MPS I), commonly manifests with upper airway obstruction and sleep disordered breathing (SDB). The success of current therapies, including haematopoietic stem cell transplantation (HSCT) and enzyme replacement therapy (ERT) may be influenced by a number of factors and monitored using biomarkers of metabolic correction. We describe the pattern of SDB seen in the largest MPS I cohort described to date and determine therapies and biomarkers influencing the severity of long-term airway disease.

Methods

Therapeutic, clinical and biomarker data, including longitudinal outcome parameters from 150 sleep oximetry studies were collected in 61 MPS I (44 Hurler, 17 attenuated) patients between 6 months pre to 16 years post-treatment (median follow-up 22 months). The presence and functional nature of an immune response to ERT was determined using ELISA and a cellular uptake inhibition assay. Multivariate analysis was performed to determine significant correlators of airway disease.

Results

The incidence of SDB in our cohort is 68%, while 16% require therapeutic intervention for airway obstruction. A greater rate of progression (73%) and requirement for intervention is seen amongst ERT patients in contrast to HSCT treated individuals (24%). Multivariate analysis identifies poorer metabolic clearance, as measured by a rise in the biomarker urinary dermatan sulphate: chondroitin sulphate (DS:CS) ratio, as a significant correlator of increased presence and severity of SDB in MPS I patients (p = 0.0017, 0.008). Amongst transplanted Hurler patients, delivered enzyme (leukocyte iduronidase) at one year is significantly raised in those without SDB (p = 0.004). Cellular uptake inhibitory antibodies in ERT treated patients correlate with reduced substrate clearance and occurrence of severe SDB (p = 0.001).

Conclusion

We have identified biochemical and therapeutic factors modifying airway disease across the phenotypic spectrum in MPS I. Interventions maximising substrate reduction correlate with improved long-term SDB, while inhibitory antibodies impact on biochemical and clinical outcomes. Monitoring and tolerisation strategies should be re-evaluated to improve detection and minimise the inhibitory antibody response to ERT in MPS I and other lysosomal storage diseases. Future studies should consider the use of sleep disordered breathing as an objective parameter of clinical and metabolic improvement.

Non-neuronopathic lysosomal storage disorders: Disease spectrum and treatments

Distinctive facial features, hepatosplenomegaly or cardiomyopathy with or without associated skeletal dysplasia are clinical manifestations that may be suggestive of an underlying lysosomal storage disorder (LSD), However, these features may not be evident in certain subtypes associated primarily with central nervous system involvement. Age at onset can be broad, ranging from infancy to adulthood. Diagnosis may be delayed, as manifestations may be slow to evolve (taking months to years), particularly in those with later (adult-)onset, and in isolated cases (i.e., those without a prior family history). Diagnosis of individual subtypes can be confirmed using a combination of biochemical and molecular assays. In a few LSDs, treatment with hematopoietic stem cell transplantation, enzyme replacement or substrate reduction therapy is available. Symptomatic and palliative measure may enhance quality of life for both treatable and currently untreatable cases. Genetic counseling is important, so patients and their families can be informed of reproductive risks, disease prognosis and therapeutic options. Investigations of underlying disease mechanisms are enhancing knowledge about rare diseases, but also other more common medical conditions, on account of potential convergent disease pathways.

Clinical neurogenetics: neuropathic lysosomal storage disorders

The lysosomal storage disorders are a clinically heterogeneous group of inborn errors of metabolism, associated with the accumulation of incompletely degraded macromolecules within several cellular sites. Affected individuals present with a broad range of clinical problems, including hepatosplenomegaly and skeletal dysplasia. Onset of symptoms may range from birth to adulthood. Most are associated with neurologic features. Later-onset forms are often misdiagnosed as symptoms, which might include psychiatric manifestations, are slowly progressive, and may precede other neurologic or systemic features. Symptomatic care, which remains the mainstay for most subtypes, can lead to significant improvement in quality of life.

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.

Perioperative complications in patients diagnosed with mucopolysaccharidosis and the impact of enzyme replacement therapy followed by hematopoietic stem cell transplantation at early age

BACKGROUND

Mucopolysaccharidoses (MPS) are hereditary storage diseases; airway management typically worsens in these patients with the progression of the disease.

OBJECTIVE(S)

To assess the incidence of perioperative complications in children with MPS and the impact of enzyme replacement therapy (ERT) followed by hematopoietic stem cell transplantation (HSCT).

METHODS

The records of patients with MPS treated with ERT followed by HSCT, who received anesthesia at the Wilhelmina Children's Hospital between 2003 and 2012, were reviewed. Data were collected on incidence of perioperative respiratory and cardiovascular complications and the impact of treatment and age.

RESULTS

Nineteen children with MPS were identified (including 17 Hurler patients), who received ERT treatment followed by HSCT. Median age at start of treatment was 14 (range: 7-43) months. Patients were anesthetized 136 times. The incidence of respiratory and cardiovascular complications was 24% and 4%, respectively. Airway management by face mask was difficult in 7%. There were no problems with the laryngeal mask airway. Tracheal intubation was difficult in 25% and failed in 10%; using a video laryngoscope was most successful (89%), followed by classic laryngoscope (67%) and fiber-optic scope (20%). Multivariate logistic regression analyses showed that the incidence of perioperative respiratory problems did not increase with age or decrease after start of treatment.

CONCLUSION

Perioperative airway management was most successful using a laryngeal mask airway or video laryngoscope. Treatment with ERT followed by HSCT and patient age did not influence the incidence of perioperative respiratory problems.

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.