In a child with DiGeorge syndrome presenting with a seizure, what is the most likely cause of the seizure when the child also has recurrent pneumonias?

In a child with DiGeorge syndrome who is experiencing seizures along with recurrent pneumonias, the most likely cause of the seizures is a brain abscess. DiGeorge syndrome, characterized by thymic hypoplasia and immune dysfunction, predisposes affected individuals to various infections, including recurrent pneumonia, primarily due to lack of functional immune response.

An important complication of chronic infections in these patients can be the formation of a brain abscess if the infection spreads to the central nervous system, either through hematogenous dissemination or direct extension. This can lead to localized inflammation and edema in the brain, resulting in seizures.

In children with compromised immune systems, such as those with DiGeorge syndrome, the risk of developing brain abscesses from infections is heightened. While other options, like brain tumors or epileptic disorders, can cause seizures, the context of recurrent pneumonias specifically highlights the increased risk of brain abscess formation in this immunocompromised patient population.