A 35-year-old woman presented with increasing drowsiness on a background of childhood meningitis and hydrocephalus managed with a ventriculopleural shunt. Her cerebral CT and chest radiograph were unchanged from previous imaging and did not identify significant pathology. Because of clinical suspicion of cerebrospinal fluid shunt dysfunction, she was referred for a cerebrospinal fluid shunt study, which demonstrated tracer accumulation within a loculated pleural collection in the left costophrenic recess.