1166

Abstract

Case Reports: Spontaneous pneumocephalus is rare in infants, and is most often associated with trauma and central nervous system instrumentation. In adults, occasional cases have been reported associated with middle ear infections and mixed anaerobic central nervous system infections. We report a neonate with extensive pneumocephalus caused by Citrobacter koseri meningitis in the absence of any other predisposing factors. A three week old male, delivered vaginally at 34 weeks after a preterm labor complicated by prolonged rupture of membranes, presented with lethargy, hypothermia and feeding difficulties. Physical examination was remarkable for a tense anterior fontanel, poor capillary refill, tachycardia, pallor and severe hypotension. He was intubated and received intravenous ampicillin and gentamicin. He also required maximal vasopressor support for septic shock. Cerebrospinal fluid (CSF) revealed severe leukocytosis, low glucose and elevated protein, and gram negative organisms on smear. Portable computed tomography of the brain was performed and revealed extensive diffuse pneumocephalus, micro abscesses and loss of gray-white differentiation. Meropenem was added and gentamycin was changed to amikacin due to concern for more invasive organisms. Blood, respiratory and CSF cultures grew Citrobacter koseri within 24 hours. Unfortunately, he died within 36 hours of admission secondary to multi-organ failure. Autopsy of the brain demonstrated generalized edema, extensive hemorrhage and diffuse cortical necrosis. Microscopy revealed bacteria laden macrophages in the leptomeninges. Discussion: Citrobacter species accounts for 4 percent of neonatal meningitis with a 30 percent mortality rate despite prompt treatment. Most affected infants are less than 6 weeks of age and one third are born premature. Citrobacter species are facultative anaerobic gram negative bacilli that can hydrolyze urea and ferment glucose, resulting in production of gas. Cerebral ischemia may also contribute by hindering the absorption of the gas produced. This case emphasizes the severe nature of Citrobacter infection and the importance of considering Citrobacter in the differential diagnosis of spontaneous pneumocephalus in neonates.