ABSTRACT
BACKGROUND: Paralysis of the diaphragm in newborn infants can lead to recurrent infections and life-threatening respiratory insufficiency. The clinical diagnosis of unilateral diaphragmatic paralysis has been reported in infants with laboratory evidence of congenital Zika virus infection and/or the congenital Zika syndrome (CZS) phenotype but no evaluation of phrenic nerve function has been described. All reported infants have had accompanying arthrogryposis. High infant mortality is reported. METHODS: The causal mechanism of congenital diaphragmatic paralysis was evaluated in three infants with arthrogryposis as a manifestation of CZS (two of the three infants had laboratory evidence of ZIKV infection shortly after birth; the remaining infant had negative serology for ZIKV when first tested at 7 months of age). Electromyography and phrenic nerve compound muscle action potential (CMAP) were performed in all infants with diaphragmatic paralysis demonstrated on imaging studies. RESULTS: All infants had evidence of moderate chronic involvement of peripheral motor neurons. Phrenic nerve CMAP was reduced on the side of the diaphragmatic paralysis in two infants and reduced bilaterally in the remaining infant who had primarily anterior involvement of the diaphragm. All three infants had multiple medical complications and one infant died at 18 months of age. CONCLUSION: Evaluation of three infants with CZS and diaphragmatic paralysis demonstrated phrenic nerve dysfunction. In these and other affected infants, arthrogryposis appears to be a constant co-occurring condition and health problems are significant; both conditions are likely due to involvement of the peripheral nervous system in some infants with CZS.