The stylohyoid ligament in Hurler syndrome and related conditions: comparison with normal children

Imaging features of mucopolysaccharidoses in the head and neck

Ear, Nose and Throat (ENT) involvement by mucopolysaccharidoses is very common, affecting over 90% of patients, and occurs early in the course of the disease. Airway narrowing secondary to glycosaminoglycan deposition results in greatly increased morbidity, mortality and risk of anesthetic complications in these patients. Macroglossia, restricted mouth opening, tracheobronchomalacia, adenotonsillar hypertrophy along with other factors such as a short, rigid and unstable cervical spine, cardiac disease and increased susceptibility to respiratory infections result in a high perioperative mortality and morbidity. Imaging is most beneficial for evaluation of the airway, in particular in patients with obstructive symptoms and prior to intubation. We review the ENT manifestations of mucopolysaccharidoses including airway involvement, otological, oral and dental complications. 3-D reconstructions of the trachea, which is routinely captured on CT imaging of the spine, can be of great value for planning intubation in this patient population.

Oral features and dental health in Hurler Syndrome following hematopoietic stem cell transplantation

BACKGROUND

Hurler Syndrome is associated with a deficiency of a specific lysosomal enzyme involved in the degradation of glycosaminoglycans. Hematopoietic stem cell transplantation (HSCT) in early infancy is undertaken to help prevent the accumulation of glycosaminoglycans and improve organ function.

AIM

To investigate the oral features and dental health of patients with Hurler Syndrome who have undergone successful HSCT.

MATERIALS AND METHODS

Twenty-five patients (median age 8.6 years) post-HSCT (mean age 9.4 months) underwent oral assessment (mean of 7.5 years post-HSCT).

RESULTS

Dental development was delayed. Numerous occlusal anomalies were noted including: open-bite, class III skeletal base, dental spacing, primary molar infra-occlusion and ectopic tooth eruption. Dental anomalies included hypodontia, microdontia, enamel defects, thin tapering canine crowns, pointed molar cusps, bulbous molar crowns and molar taurodontism. Tooth roots were usually short/blunted/spindle-like in permanent molars. The prevalence of dental caries was low in the permanent dentition (mean DMFT 0.7) but high in the primary dentition (mean dmft 2.4). Oral hygiene instruction with plaque and or calculus removal was indicated in 71% of those that were dentate.

CONCLUSION

Patients with Hurler Syndrome post-HSCT are likely to have delayed dental development, a malocclusion, and dental anomalies, particularly hypodontia and microdontia.

alpha-L-iduronidase therapy for mucopolysaccharidosis type I

More than 500 patients with mucopolysaccharidosis type IH (MPS IH; Hurler syndrome) have been treated with hematopoietic cell transplantation (HCT) throughout the world since the introduction of transplantation as therapy almost 30 years ago. More recently, the availability of recombinant alpha-L-iduronidase (IDUA) has resulted in the widespread treatment of less severe forms of MPS I with enzyme replacement therapy (ERT). In addition, over 50 MPS IH patients have been treated with a combination of ERT and HCT. The rationale for both ERT and HCT stems from the pivotal experiments performed 4 decades ago that showed alpha-L-iduronidase supplied in the environment can correct the accumulation of substrate in MPS I cells. Our purpose is to address the multiple applications associated with the therapeutic delivery of IDUA: intermittent delivery of recombinant protein (ERT), continuous administration through cellular therapy (HCT), the use of other stem cells or, potentially, correction of the enzyme defect itself through gene therapy approaches. Even though gene therapy and non-hematopoietic stem cell approaches, have yet to be tested in a clinical setting, it is possible that all these approaches will in the near future be a part of a paradigm shift from unimodal to multimodal therapy for MPS I.

Elongated styloid process and Eagle's syndrome

A controversial entity, Eagle's syndrome, is reviewed. After an anatomical description of the maxillo-vertebro-pharyngeal region we summarize the causative, diagnostic and therapeutic aspects of the syndrome. Two different conditions are often reported as Eagle's syndrome: one characterized by dysphagia and unilateral pharyngeal pain radiating to the ear and worsened by swallowing; the other characterized by pain in the head and neck region due to compression of the neurovascular structure by an elongated styloid process. The latter also includes typical cranial neuralgias (such as glossopharyngeal neuralgia) and carotidynia. We believe that the term "Eagle's syndrome" is legitimate only in the first case and in those "atypical" painful head and neck conditions related to an elongated styloid process and relieved by styloidectomy. We believe Eagle's syndrome deserves consideration in the International Headache Classification.

Airway obstruction in Hurler's syndrome--radiographic features

The mucopolysaccharidosis (MPS) diseases are progressive clinical disorders which are characterized by a deficiency of lysosomal enzymes. In MPS I (Hurler's syndrome), reduced activity of alpha-L-iduronidase leads to intralysosomal storage of dermatan and heparan sulfate in various tissues. Airway obstruction is a frequent problem in these patients, often secondary to abnormal cervical vertebra, a short neck, a high epiglottis, and mucopolysaccharide infiltration of the soft tissues in the upper aerodigestive tract. Evaluation of these abnormalities may include plain film and videofluoroscopic examinations of the airway. The therapeutic and diagnostic implications of such studies are discussed in a review of 4 patients with Hurler's syndrome manifesting upper airway obstruction.