Cerebral Anoxia in an 18-year-old Patient Being Treated for Major Depressive Disorder: How Forensic Detective Work Uses Medical Knowledge Including Clinical Pharmacology to Solve Cases.

This column is the first of a 3-part series illustrating the importance of medical knowledge, including clinical pharmacology, in a forensic context. This first case involved an 18-year-old high school student who suffered an anoxic brain injury and remained in a state of permanent decorticate posture, unresponsive except for grunts and primitive movements until he died several years later. Our investigation began by ruling out plausible causes that were suggested by the defense in the malpractice suit. Once those possibilities were eliminated, the focus was on what accounted for the damage to the patient using general medical knowledge and clinical pharmacology. The 4 Ds of forensic psychiatry (duty, damages, dereliction, and direct cause) are the 4 elements that the plaintiff is required to prove in civil court to prevail in a malpractice suit and are applied to this case with a special focus on dereliction and direct cause. This catastrophic outcome was due to 3 factors. First, the patient had physiologically significant dehydration to the point that he had developed a reflex tachycardia to maintain his blood pressure. Second, the patient had been switched from extended to immediate-release quetiapine, resulting in a doubling of the peak concentration of the drug, which produced higher occupancy of alpha-1 adrenergic, histamine-1, and dopamine-2 receptors, causing a further drop in his blood pressure as well as increased sedation and impairment of his gag reflex. These effects occurred quickly because of the faster absorption of the IR formulation of the drug. Third, the patient had gone to sleep in a reclining chair so that his brain was above his heart and his lower extremities were below his heart, resulting in an increased "steal" of cardiac output going to his brain. These 3 factors together led the patient to aspirate and suffer a hypoxic brain injury after an episode of vomitus. This column explains the process by which the cause of this sad outcome was determined, how it was related to a dereliction of duty to the patient, and how other proposed causes were ruled out.