Normal pressure hydrocephalus found after anesthesia--a case report.

Normal pressure hydrocephalus (NPH) is characterized by insidious onset and gradual development of the triad of gait disturbance, dementia, and urinary incontinence. Nausea, vomiting, and signs of increased intracranial pressure do not occur. A 71-year-old male patient was scheduled for total knee replacement due to osteoarthritis of right knee joint. No neurological symptoms and signs except mild forgetfulness were detected during physical examination following admission. Due to operational mistakes, the anesthesiologist was informed that the surgery was cancelled just after completion of induction of general anesthesia. The patient was allowed to emerge from anesthesia. Unfortunately, his consciousness became drowsy the next morning. After a series of examinations, he was at last diagnosed as a case of NPH principally by the brain computed tomography scan. So he was scheduled again but this time for vetriculoperitoneal (V-P) shunt. The patient regained consciousness after V-P shunt. From this case, we learned that NPH may remain in concealment in the patients we contacted in our daily practice. A vigilant physician should keep in mind that the presentation of gait disturbance, dementia, and urinary incontinence in a patient may indicate the likelihood of NPH.