Our patient was diagnosed with bronchopulmonary sequestration (BPS). His chest CT showed large caliber systemic arterial vessels arising from the celiac trunk below the diaphragm which were supplying an abnormal portion of the left lower lobe, suggestive of previously undiagnosed BPS. The CT also showed normal pulmonary venous return via the left lower pulmonary vein. Additionally, the CT revealed findings most consistent with necrotizing pneumonia within the sequestered portion of the lung and a small left pleural effusion. It is believed that this sequestered portion of his lung placed him at an elevated risk for infections as this is a known complication of bronchopulmonary sequestration. 

Bronchopulmonary sequestration is a rare type of congenital lung malformation (CLM) in which a section of lung tissue is nonfunctional and does not communicate with the normal tracheobronchial tree. With improved access to prenatal care and ultrasounds, CLMs are commonly detected prenatally. Some cases will become symptomatic in the newborn period with presentations such as infection, respiratory distress, or high-output heart failure, however a smaller portion of patients with BPS are not diagnosed prenatally and either become symptomatic later in life (such as our patient) or remain asymptomatic and are incidentally noted on imaging. Congenital lung malformations are seen in about 1 in 2,500 to 8,000 live births, and BPS accounts for 0.15 to 6.4% of all CLMs. Other forms of CLMs include congenital pulmonary airway malformation, bronchogenic cysts, congenital lobar emphysema, and bronchial atresia.

This patient was admitted to the general pediatrics service and initially started on ceftriaxone and clindamycin. After one day he was transitioned to oral levofloxacin and clindamycin to complete a 2-week antibiotic course. He remained off respiratory support and was discharged on day 3 of admission to complete the remainder of his antibiotic course at home. Pulmonology and surgery were consulted during his hospital stay, and he has since had a left lower lobectomy after healing from his pneumonia. 

An important point from this case is to consider CT imaging when a child has persistent or recurrent pneumonia. Most patients are afebrile by the third day of treatment and clinically improved within two weeks. In addition to CLMs, the differential diagnosis for these patients includes an airway obstruction, aspirated foreign body serving as an infectious nidus, and immunologic disorder.