Respiratory System

Chronic recurrent rhinitis and rhinorrhea without obvious infectious etiology are common features of MPS I. Storage within the oro-pharynx with associated enlargement of the tonsils and adenoids can lead to significant upper airway complications.^[1][2] In severe MPS I patients, a narrowed trachea, thickened vocal cords, redundant tissue in the upper airway and an enlarged tongue all contribute to airway obstruction.^[3][4][5]

Noisy breathing is a general consequence of upper airway obstruction. In many MPS I individuals, airway obstruction often leads to sleep apnea, particularly during the later stages of disease and can reflect both otolaryngeal (obstructive) as well as CNS (central) involvement. Low-flow oxygen with appropriate precautions for patients chronically retaining CO₂ can be used. Often tracheostomy is required to maintain the airway and control pulmonary hypertension and right-heart failure.

Patients develop restrictive-type lung disease from a combination of factors, including reduced diaphragmatic excursion from hepatosplenomegaly, spinal deformities, and a small, non-compliant rib cage. Respiratory insufficiency leads to atelectasis, shortness of breath and pulmonary infections.

Tonsillectomy and adenoidectomy are frequently performed to correct eustachian tube dysfunction and decrease airway obstruction. Early surgical treatment may be recommended because of the increasing risks of anesthesia with disease progression. ^[1][2][6]

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References:

1. Clarke, L.A. (1997) Clinical diagnosis of lysosomal storage diseases. In: Organelle Diseases. Clinical Features, Diagnosis, Pathogenesis and Management. Applegarth, D.A., Dimmick, J.E., and Hall, J.G. (eds.). Chapman and Hall Medical, London, pp. 37.

2. Neufeld, E.F., and Muenzer, J. (2001) The mucopolysaccharidoses. In: The Metabolic and Molecular Bases of Inherited Disease. Scriver, C.R., Beaudet, A.L., Sly, W.S., Valle, D., Childs, B., Kinzler, K.W., and Vogelstein, B. (eds.). 8th edition, Vol. III. McGraw- Hill, Medical Publishing Division, pp. 3421.

3. Myer, C.M.D. (1991) Airway obstruction in Hurler’s syndrome – Radiographic features. Int J Pediatr Otorhinolaryngol 22: 91.

4. Peters, M.E., Arya, S., Langer, L.O., Gilbert, E.F., Carlson, R., and Adkins, W. (1985) Narrow trachea in mucopolysaccharidoses. Pediatr Radiol 15: 225.

5. Shapiro, J., Strome, M., and Crocker, A.C. (1985) Airway obstruction and sleep apnea in Hurler and Hunter syndromes. Ann Otol Rhinol Laryngol 94: 458.

6. Moores C, Rogers JG, McKenzie IM, Brown TC. Anaesthesia for children with mucopolysaccharidoses. Anaesthesia and intensive care 1996;24(4):459-63.