Centrally mediated obstructive apnoea and restenosis of the foramen magnum in an infant with achondroplasia.

Achondroplasia is associated with foramen magnum stenosis. We report a male infant with achondroplasia and centrally mediated obstructive apnoea who underwent two foramen magnum decompression due to bone regrowth. He presented at six weeks of age with breath holding and apnoeic episodes associated with significant desaturation, requiring non-invasive ventilation. Craniospinal imaging revealed a narrow foramen magnum without signal change in the spinal cord. Sleep studies showed obstructive, but not central, apnoea. Respiratory abnormalities persisted and reimaging at two months showed development of significant signal changes at the cervicomedullary junction (CMJ). He underwent emergency foramen magnum decompression with initial clinical improvement. Ten days later he relapsed with further apnoeic episodes requiring respiratory support. After extensive re-investigations including CT and MRI, incomplete initial decompression and foramen magnum restenosis were considered and confirmed with a CT head scan 15 weeks after the initial operation. Repeat decompression of bone and removal of thickened dural bands resulted in complete resolution of the apnoeic episodes. Obstructive sleep apnoea can be centrally mediated and further decompression of foramen magnum stenosis should be considered, especially if significant respiratory compromise persists or recurs.

Postnatal impact of a prenatally diagnosed double aortic arch.

BACKGROUND: A double aortic arch (DAA) is increasingly identified before birth; however, there are no published data describing the postnatal outcome of a large prenatal cohort. OBJECTIVE: To describe the associations, symptoms and impact of prenatally diagnosed DAA. METHODS: Retrospective review of consecutive cases seen at two fetal cardiology units from 2014 to 2019. Clinical records including symptoms and assessment of tracheobronchial compression using flexible bronchoscopy were reviewed. Moderate-severe tracheal compression was defined as >75% occlusion of the lumen. RESULTS: There were 50 cases identified prenatally and 48 with postnatal follow-up. Array comparative genomic hybridisation (aCGH) was abnormal in 2/50 (4%), aCGH was normal in 33/50 (66%) and of those reviewed after birth, 13 were phenotypically normal. After birth, there was a complete DAA with patency of both arches in 8/48 (17%) and in 40/48 (83%) there was a segment of the left arch which was a non-patent, ligamentous connection.Stridor was present in 6/48 (13%) on the day of birth. Tracheo-oesophageal compressive symptoms/signs were present in 31/48 (65%) patients at median age of 59 days (IQR 9-182 days). Tracheal/carinal compression was present in 40/45 (88%) cases. Seven of 17 (41%) asymptomatic cases demonstrated moderate-severe tracheal compression. All morphologies of DAA caused symptoms and morphology type was not predictive of significant tracheal compression (p=0.3). CONCLUSIONS: Genetic testing should be offered following detection of double aortic arch. Early signs of tracheal compression are common and therefore delivery where onsite neonatal support is available is recommended. Significant tracheal compression may be present even in the absence of symptoms.