Title: An Infrequent Cause of Respiratory Failure
History: A 30-year-old gravida 3 para 2 mother was induced at 39 3/7 weeks gestation due to newly diagnosed oligohydramnios (AFI 3.3) and intrauterine growth restriction. Pregnancy was complicated by late presentation to prenatal care at 20 weeks, maternal Graves disease, cognitive impairment, and polycystic ovary syndrome. Infant was born via vaginal delivery with APGARS of 9 and 9 and was placed skin to skin. At 35 minutes of life, the infant was noted to have respiratory distress and desaturations ultimately requiring intubation and acute transfer.
Physical Exam: Exam was significant for mild hypotelorism, upturned nose, mild micro- retrognathia, left single palmar crease, and right second and third toe syndactyly. Decreased aeration was noted on auscultation of lungs with significant WOB. Initial oxygen saturations were 60%, requiring facial CPAP 1.0 FiO2. Other vital signs were within normal limits.
Laboratory/ Diagnostic Imaging/ Procedures: Infant was unable to tolerate transition to RAM cannula CPAP and required intubation with immediate resolution of hypoxia and work of breathing. Intubation was uncomplicated with no airway abnormalities noted. CXR showed clear lung fields bilaterally with midline trachea. NGT unable to be passed through nares. Flexible fiberoptic laryngoscopy attempted with inability to pass into the nasopharynx bilaterally. Serial axial CT images were obtained of the facial bones which revealed severe bony narrowing with soft tissue completely occluding the bilateral posterior nasal passages with retention of secretions, slight thickening of the vomer bone and medial bowing of maxillary sinuses. On further history gathering mom was on methimazole throughout pregnancy. Infant underwent transnasal endoscopic repair of bilateral choanal atresia on DOL5. Repair complicated by need for bilateral nasal debridement and subsequent dilation of nasopharynx as well as steroid injections for edema.
Final Diagnosis and Discussion: Choanal atresia is a congenital obstruction of the posterior choanae which occurs in 1 in 10,000 live births with a female predominance. Only one third of cases are bilateral. There have been several case reports suggesting a relationship between methimazole use during pregnancy leading to a methimazole embryopathy. However, there are even rarer case reports of methimazole use during pregnancy leading to bilateral choanal atresia with dysmorphic features as detailed in the case discussed here. Choanal atresia should be evaluated for in any infant with first trimester methimazole exposure to facilitate early diagnosis and avoid respiratory compromise.
