Exacerbations in neuroendocrine cell hyperplasia of infancy are characterized by increased air trapping.

Neuroendocrine cell Hyperplasia of Infancy (NEHI) presents with tachypnea, retractions, hypoxemia, and often failure to thrive. The radiologic and physiologic findings in infants with NEHI have been well described with a distinct geographic pattern of ground-glass opacities on chest computerized tomography imaging and profound air-trapping on infant pulmonary function testing. Despite gradual improvement over time, unexplained exacerbation has been observed but not well characterized. We present physiological and radiological changes of increased air-trapping during acute exacerbations in two older children with NEHI who had previously experienced significant clinical improvement. These cases illustrate previously undescribed manifestations of NEHI in older children.