Which of the following would be an uncommon finding with hallucinogen intoxication?
ExplanationD. This patient exhibits symptoms of intoxication with phenylcyclohexyl piperidine, more commonly known as phencyclidine (PCP). This was a drug developed initially as a dissociative anesthetic, primarily used in animals. It is structurally similar to ketamine, which is used for medical anesthesia. Hypertension, tachycardia, nystagmus (vertical, lateral, horizontal, or rotatory), decreased pain sensation (often causing superhuman appearance of strength), rage, muscle rigidity, seizures, bizarre behaviors, hallucinations, delusions, impaired judgment, confusion, dysarthria, ataxia, and myoclonic jerks are all characteristic findings in PCP intoxication. Its use can also lead to hyperthermia, autonomic instability, and multiorgan failure. PCP is used by oral, intravenous, or intranasal routes. It acts as a noncompetitive antagonist at the glutamate NMDA receptor. PCP has been shown to affect biogenic amine (dopamine, norepinephrine, serotonin) release and reuptake. These actions probably account for the sympathomimetic effects of PCP. PCP is structurally similar to ketamine, but it differs from ketamine in that it is longer acting, is more likely to cause seizures, and tends to cause more emergent confusion and delirium. Ketamine also acts as a noncompetitive antagonist of the NMDA receptor. It also has interactions with muscarinic, nicotinic, and cholinergic receptors and inhibits reuptake of norepinephrine, dopamine, and serotonin. The other choices listed are of the psychedelic or hallucinogenic category. Although some symptoms can overlap with PCP intoxication, the symptoms described in this case are characteristic of PCP. Psilocybin (4-phosphoryloxy-N, N-dimethyltryptamine) comes from specific types of mushrooms, and mescaline comes from the peyote cactus. Lysergic acid is one of the ergot fungus’ diverse alkaloid components, and lysergic acid diethylamide was popularized as a potent mood-changing and hallucinogenic drug. Use of the different hallucinogens leads to many similar symptoms including sensory distortions (such as synesthesias; “feeling” colors, “seeing” sound), illusions, hallucinations, euphoria, anxiety, tachycardia, palpitations, pupillary dilation (as opposed to opiates, which cause miosis), and diaphoresis. The hallucinogens primarily work at various serotonergic receptors. Different receptor subtypes are modulated by these various drugs, some of which may do so through agonism, whereas others through antagonism. The serotonin 5HT2 receptor is particularly thought to be involved in the action of these drugs. Some of these drugs may have some effects at dopamine and norepinephrine receptors. In addition, 3, 4- methylenedioxymethamphetamine (MDMA), or ecstasy, blocks reuptake of serotonin, and prolonged use of MDMA results in destruction of serotonergic neurons in the brain.
