Sonographic Diagnosis of Meningoencephalitis in Newborns and Infants.

Prenatal, neonatal meningoencephalitis and infections of the brain in older infants are often associated with serious complications which can be diagnosed by sonography through the open fontanelles. Most frequently postmeningitic hydrocephalus and subdural effusions occur. Rarer complications are brain abscesses and ventriculitis which are caused by gram negative bacteria such as E. coli, Serratia marcescens, Proteus and Enterobacter. A serious complication after ventriculitis is the development of compartment hydrocephalus. Multifocal small echogenic lesions scattered all over the brain are suspicious of fungal infections. Stripe-like echogenicities in the basal ganglia of newborns are typical for prenatal infections such as infections with cytomegalovirus, rubella, herpes, toxoplasma gondii and HIV. Late sequelae are intracranial cysts, multifocal encephalomalacia and intracranial calcifications. Color Doppler shows increased perfusion of the brain in the acute phase of the disease. Brain abscesses and infarcts are characterized by decreased or missing perfusion. Spectral Doppler shows increased flow velocities. Increased intracranial pressure causes an increase of the flow velocities in the intracranial part of the internal carotid artery in comparison with the extracranial part. All complications can be diagnosed by ultrasound. Other imaging methods such as MRI are only occasionally necessary.