Lumbar puncture is a commonly practiced bedside technique for acquiring cerebrospinal fluid for the purposes of examination, spinal anesthesia, and as therapeutic trial for normal pressure hydrocephalus. Headache and backache after lumbar puncture are not uncommon. We report an elderly woman who suffered from altered consciousness and acute neurologic deficit after a difficult lumbar puncture. Serial imaging studies revealed active bleeding from the left first lumbar artery with the formation of spinal epidural hematoma and coexisting acute cranial intraventricular hematoma and subarachnoid hemorrhage. Lumbar puncture may rarely associate with life-threatening complications. Acute spinal subdural hemorrhage or subarachnoid hemorrhage after lumbar puncture is a timely diagnosis and needs urgent interventions. Clinicians should be aware of these rare but life-threatening complications after lumbar puncture. A cranial unenhanced CT is mandatory for patients having acute altered consciousness after lumbar puncture. A thorough vascular imaging evaluation from the lumbar spine to the brain is warranted in selected cases.