RESPIRATORY PROBLEMS IN ACHONDROPLASIA

Abstract

A significant number of infants and children with achondroplasia have respiratory complications. Suggested etiologies include: 1) upper airway obstruction, 2) thoracic cage deformity and 3) neurologic dysfunction. We prospectively evaluated 10 achondroplasts (6 males, 4 females, ages 4 mos-6 yrs) for respiratory problems. 2/10 were asymptomatic, 3/10 had mild symptoms (3 with tachypnea, 1 with pneumonia) and 5/10 had severe symptoms (2 with obstructive sleep apnea [OSA] , 3 with episodic cyanosis while awake and/or recurrent pneumonia). Nasal airflow was compromised and hyperextended neck posture was assumed during sleep in 6/10. Chest circumference was < 3rd percentile for age in 6/10. Asymmetric hyperreflexia was found in 3/10. Cor pulmonale was diagnosed by echocardiography in 6/10, including 1 with mild symptoms. Arterial hypoxemia (PO2<75) while awake was found in 4/10 and sleeping hypoxemia in 6/10. In the 2 hypoxemic infants evaluated, low tidal volumes were found. Polysomnograms confirmed OSA in 2/10 and mixed apnea in 1/10. In 2 hypoxemic infants, small chest circumference was the only clear etiology found. Cervicomedullary cord compression was diagnosed by CT and evoked potentials in 4/10 (2 with episodic cyanosis, 1 with OSA and 1 with tachypnea and pneumonia). Thus in only 3/8 with respiratory complications could a single etiology be implicated; 5/8 had at least two etiologies. We conclude that symptomatic patients require comprehensive evaluation to delineate all possible etiologies in order to clarify treatment.