Respiratory complications of metatropic dwarfism

Two infants with clinical and radiologic features of metatropic dwarfism presented in the neonatal period with episodes of cyanosis. Diagnostic studies to determine the etiology of these spells, including electrocardiogram, electroencephalogram, arterial blood gases, and metabolic and sepsis studies, were unremarkable. Chest roentgenograms revealed the characteristic long, narrow thoracic cage with no evidence of parenchymal disease. Cervical spine stability evaluation, pulmonary function studies, and chest impedance monitoring with qualitative air flow thermistor studies and transcutaneous oxygen monitoring were carried out. Both patients demonstrated a significant increase in resistance of the respiratory system following passive maneuvering of the head from a neutral position, suggestive of hypopharyngeal air flow obstruction. Obstructive sleep apnea resulting in cyanosis was documented in both patients. All other studies failed to yield a cause for the episodes of cyanosis. Our investigation failed to alter the clinical course which resulted in respiratory arrest and death by 7 months of age. A table is presented for the differentiation of skeletal dysplasias presenting in the perinatal period.