Introduction Lumbar dermoid cysts and other occult dysraphisms are sometimes difficult to diagnose. These anomalies are occasionally detected after a nervous central system infection.
Case Report Previously healthy 10 month-old child, admitted after a first febrile generalized seizure with nuchal rigidity and bulging fontanel. A very small blind lumbar dimple above the 5th lumbar vertebra was noticed. Cerebrospinal fluid (CSF) was consistent with bacterial meningitis and penicillin susceptible Klebliella spp was identified. Brain CT-scan was normal and CSF was sterile after 4 days of ceftriaxone. She completed 21 days of therapy, with clinical improvement. One week after, she was readmitted with fever, lethargy and opisthotonus. Klebsiella oxytoca meningitis was diagnosed and treated for 3 weeks with ceftriaxone and gentamicin, according to antibiotic susceptibility test. Brain and spine magnetic resonance imaging showed a L4-L5 lumbo-sacral intrarachidian dermoid cyst with a fistulous path to skin surface. Surgical closure of fistula was performed on day 23 of therapy. This child is currently under antibiotic chemoprophylaxis with amoxicillin/clavulanate, awaiting removal of dermoid cyst under optimal sterile conditions. Neurological exam and motor development have been normal.
Conclusions A strong clinical suspicion is necessary in order to diagnose occult dysraphism and spinal midline cysts, before complications occur. A careful examination of the midline is warranted in all infants, paying special attention to skin pits outside coccigeal area, even if apparently blind. This diagnosis should also be considered in cases of recurrent or unusual bacterial associated central nervous system infections.