Sudden unexpected nocturnal death in Chiari type 1 malformation and potential role of opioid analgesics
A 29-year-old African-American male was admitted to our hospital because of headache associated with nausea, vomiting, and blurred vision. Intermittent headaches over the preceding 4 years were ascribed to CM1. In the month prior to admission, the patient's headaches had increased in frequency and in severity. He described the headaches as pounding and rated the intensity of the pain as 10 on a scale of 0 to 10, where 10 is the most severe. The pain began in the occipital region and extended to the forehead unrelated to coughing or straining. A few days before admission, nausea, vomiting, and blurred vision accompanied some of the episodes of headache. As the patient's headaches continued to worsen, he was admitted to an outside hospital. Magnetic resonance imaging (MRI) of the brain showed an 18 mm cerebellar tonsillar herniation and a disproportionately large communicating fourth ventricle with dilated but stable ventricular system, and no change from previous studies []. Cervical spine MRI was normal. In light of the patient's worsening symptoms, he was transferred to the University Hospital of Brooklyn for surgical intervention. The patient did not report limb weakness, paresthesia, or breathing difficulty, nor a history of cardiac arrhythmia, hypoglycemia, alcohol abuse, or epilepsy. The patient had no family history of neurologic or cardiac disease. Preadmission medications included variable amounts of acetaminophen, hydrocodone, and ibuprofen for headache control.\nOn evaluation, the patient's vital signs were normal, the lungs were clear and no bradycardia or cardiac pauses were observed. He was alert and oriented. There was no nuchal rigidity to passive flexion of the neck. The pupils were equal and reactive to light. The optic disc margins were sharp and the visual fields were normal. The remainders of the physical and neurological examinations were normal except for mild bilateral horizontal gaze-evoked nystagmus and a slightly unsteady gait. Laboratory studies, including complete blood count, serum electrolytes, blood glucose, urine specimen, and the results of the blood pressure and heart rate monitoring were normal. The patient was considered in stable condition because of a stable ventricular size with stable vital signs, relative preservation of motor and sensory pathways, and no respiratory stress during alertness. In light of his presumed stable condition, medical management of the patient's acute cephalodynia rather than urgent surgery became the priority. He was disconnected from the vital signs monitor and admitted to the neurosurgical ward for surgery to be scheduled after presurgical risk assessment testing, including routine laboratory studies, chest X-ray, and electrocardiogram. Medical management of the patient's pain during the first 24 hours of admission, starting in the emergency room and continuing in the neurosurgical ward, included 60 mg of codeine by mouth, 650 mg of acetaminophen by mouth, 10 mg of intravenous (IV) morphine sulfate (2, 4, and 4 mg at 4-hour intervals), 4 mg of IV hydromorphone, and 10 mg of IV metoclopramide. At 4:10 am on the second day of hospitalization, about 26 hours after admission, the patient complained of severe headache. Upon rising from bed, he became incontinent of urine. After the patient was placed in bed, hydromorphone 4 mg and metoclopramide 10 mg were given IV. At 8:00 am, the patient was found cold and pulseless in bed with no recordable blood pressure or cardiac activity on electrocardiogram and was pronounced dead. A complete postmortem examination revealed a CM1 with mild hydrocephalus without uncal herniation or syringomyelia. Toxicological screening was negative. The cause of death was not identified, but myocardial infarction, cardiac conduction defect, and suffocation due to vomiting or choking were convincingly excluded.