Cerebellar loss and brain-stem atrophy associated with neonatal alloimmune thrombocytopenia in a discordant twin.

Neonatal alloimmune thrombocytopenia (NAIT) is due to an immune-mediated maternal-fetal platelet antigen incompatibility. Central nervous system abnormalities have been reported in infants with NAIT and include intracranial hemorrhage, ventriculomegaly, porencephalic cysts, neuronal migrational disorders, and, rarely, cerebellar lesions. We present the clinical and neuropathological findings from a case of a 3-day-old diamniotic/dichorionic female twin with known bilateral ventriculomegaly born prematurely at 33-1/7 weeks in gestational age. The pregnancy was further complicated by discordant intrauterine growth, intraventricular hemorrhage in the co-twin, and NAIT. At birth, the infant was noted to have diffuse body ecchymoses and petechiae and arthrogryposis. She subsequently developed multisystem organ failure and disseminated intravascular coagulopathy and died on the 3rd day of life. Neuropathological findings at autopsy included a posterior fossa cyst with no gross anatomic evidence of a cerebellum, atrophic pons and medulla with prominent pyramidal tracts and absent olivary nuclei, thinned corpus callosum, and symmetrical dilation of bilateral lateral ventricles. Microscopic examination confirmed the gross findings and revealed no histological evidence of cerebellar tissue, absence of superior and inferior cerebellar peduncles, and acute and chronic germinal matrix hemorrhages. Immunohistochemical studies revealed a focus of reactive gliosis at the base of the posterior fossa cyst with no evidence of cerebellar Purkinje or granule cells. To our knowledge, this is the 1st report with well-characterized neuropathological examination detailing complete cerebellar loss and brain-stem atrophy in a neonate with NAIT.

Heated, humidified high-flow nasal cannula therapy: yet another way to deliver continuous positive airway pressure?

OBJECTIVE: The goal was to estimate the level of delivered continuous positive airway pressure by measuring oral cavity pressure with the mouth closed in infants of various weights and ages treated with heated, humidified high-flow nasal cannula at flow rates of 1-5 L/minute. We hypothesized that clinically relevant levels of continuous positive airway pressure would not be achieved if a nasal leak is maintained. METHODS: After performing bench measurements and demonstrating that oral cavity pressure closely approximated levels of traditionally applied nasal continuous positive airway pressure, we successfully measured oral cavity pressure during heated, humidified, high-flow nasal cannula treatment in 27 infants. Small (outer diameter: 0.2 cm) cannulae were used for all infants, and flow rates were left as ordered by providers. RESULTS: Bench measurements showed that, for any given leak size, there was a nearly linear relationship between flow rate and pressure. The highest pressure achieved was 4.5 cmH2O (flow rate: 8 L/minute; leak: 3 mm). In our study infants (postmenstrual age: 29.1-44.7 weeks; weight: 835-3735 g; flow rate: 1-5 L/minute), no pressure was generated with the mouth open at any flow rate. With the mouth closed, the oral cavity pressure was related to both flow rate and weight. For infants of < or = 1500 g, there was a linear relationship between flow rate and oral cavity pressure. CONCLUSIONS: Oral cavity pressure can estimate the level of continuous positive airway pressure. Continuous positive airway pressure generated with heated, humidified, high-flow nasal cannula treatment depends on the flow rate and weight. Only in the smallest infants with the highest flow rates, with the mouth fully closed, can clinically significant but unpredictable levels of continuous positive airway pressure be achieved. We conclude that heated, humidified high-flow nasal cannula should not be used as a replacement for delivering continuous positive airway pressure.