Lumbar spinal fluid collections in children treated with intrathecal chemotherapy: elevated CSF protein as a diagnostic clue.

Subdural fluid collections can interfere with the effective intrathecal administration of chemotherapy by lumbar puncture (LP). We detected this complication in six children who were treated for acute lymphoblastic leukemia (ALL) and presented with an elevated protein concentration of the cerebrospinal fluid (CSF) during routine LP. Contrary to expectation the lumbar fluid collections persisted in two cases and in one case required the insertion of an Ommaya reservoir to continue intrathecal chemotherapy. Awareness and detection of this complication by imaging is important because of its potential to interfere with effective CNS-directed chemotherapy of ALL.