Morquio syndrome (MS) or mucopolysaccharidosis (MPS) type IVA is a progressive lysosomal storage disorder with autosomal recessive inheritance. Literature may combine MPS type IVA and B and refer to them as Morquio syndrome, although type IV B is extremely rare and presents a far less aggravating course. A deficiency of the enzymes N-acetyl-galactosamine-6-sulphat sulphatase and beta-galactosidase compromises the catabolism of the glycosaminoglycans (GAGs) keratan sulphate and chondroitin-6-sulphate/chondroitin-4-sulphate. The GAGs accumulate excessively in soft tissue, cartilage, and bone causing severe skeletal dysplasia and a distinct phenotype. Features include dwarfism, significant pectus carinatum and kyphoscoliosis, hypoplasia of the odontoid process causing atlanto-axial instability and cervical subluxation, cervical stenosis, and deformity of joints with limited mouth opening and genu valgum (“jockey stance”). Accumulation causes deformation of the oropharyngeal and laryngeal structures, macroglossia, sleep apnea, bulgy soft tissue prone to bleeding and hypertrophic tonsils and adenoids, GAGs have a predisposition for the trachea and cornea, especially keratan sulfate (the predominant GAG in patients with MS) which accumulates in the hyaline cartilage of the anterior tracheal rings causing tracheal stenosis and tracheomalacia with position-depending obstruction.
Comorbidity is common in MS. Thoracic deformities result in severe restrictive pulmonary disease, reduced alveolar capacity, and recurrent infections. Accumulation in the coronary arteries, heart valves, and myocardium is described leading to cardiomyopathy, myocardial ischemia, and valve dysfunction. Vital organs can be affected, in particular hepato- and splenomegaly. Other comorbidity is neurological due to the spinal cord impact, skeletal, ophthalmological, and otolaryngological. In general, MS patients are wheelchair-bound as teenagers, but have a normal intelligence. In most cases, life span is limited to the second or third decade of life, pulmonary and cardiac impact being responsible for the early demise. However, life sustaining surgery and improved medical treatment have increased the life expectancy, and recommendation towards prophylactic stabilising cervical fusion suggest that more MS patients will undergo general anaesthesia in the future. Already, patients with MS undergo multiple surgical procedures majority of which are orthopaedic, heart valve, and ear-nose-throat related.
Airway management is challenging, and general anaesthesia is a high-risk procedure involving the risk of death. Much information is emerging detailing airway abnormalities that may have an impact on anaesthetic management.