The Science Journal of the American Association for Respiratory Care
Background: In this case study we describe the unusual radiographic presentation of a 36 week gestation female, who developed almost immediate respiratory distress after delivery. In working through the differential diagnosis for mediastinal shift in a newborn, we found the cause was a rather rare congenital lung malformation.
Case summary: The infant was born to a 25 year old Gravidal, Para 1. The pregnancy was complicated only by gestational diabetes which was controlled by diet. A routine ultrasound was completed at 17 weeks gestation and showed no fetal abnormalities. The child was born via spontaneous vaginal delivery with Apgars of 4,6 and 7 at 1,5 and 10 minutes respectively. Upon arrival of the transport team, the patient was in 100% FIO2 with an oxygen saturation level of 78%. The infant was very dusky and quickly desaturated to 60% with any stimulation. Breath sounds were diminished and best heard over the right axilla and left upper lobe. The patient was intubated and intravenous access obtained. A chest radiograph was obtained and showed a marked shift of the heart to the right with tracheal deviation and opacification of the left lung except for the left upper lobe. An initial arterial blood gas revealed a PaO2 of 40, PCO2 of 60 and a Ph of 7.28. The patient was placed on a Biomed MPV 100 with an IMV rate of 50, ventilating pressures of 24/4 and FIO2 initially of 100%. The patient was transported without incident. A chest and abdominal ultrasound was obtained and was suggestive of a left sided, diaphragmatic hernia. A CT scan was then performed to help confirm the diagnosis. The CT scan showed an extensive compression of the lung parenchyma and mediastinal shift by a solid appearing mass consistent with a Type III Congenital Cystic Adenomatoid Malformation (CCAM). Several days later, the patient was taken to the operating suite for resection of the CCAM. A mass measuring 7.6
Conclusion: While CCAM is a rare malformation, it represents 25% of all congenital lung malformations. The type III CCAM illustrated in this case is extremely rare as it comprises only 10% of all diagnosed cases. Health care providers who work newborns and children, especially those involved in transport need to be aware of this congenital malformation. This case further highlights the difficulty which may be encountered in establishing a diagnosis. This pathology needs to be considered in cases of mediastinal shift in the newborn.