# Stage 1 — Recognize cues. The nurse assesses the client at 0400. Highlight the findings that require immediate follow-up. > source: MyMerci (mymerci.kr) > url: https://mymerci.kr/pages/nclex_q.php?qn_id=617240&lang=en > language: en > subject: Mental Health Concepts > category: PSI ## Question Stage 1 — Recognize cues. The nurse assesses the client at 0400. Highlight the findings that require immediate follow-up. A 37-year-old adult was admitted 2 days ago for acute psychosis and was shouting and pacing on admission. The client received several intramuscular haloperidol doses over 48 hours, then a higher scheduled dose. Yesterday the client had a neck spasm that resolved after IM diphenhydramine. The client takes no antidepressant and has had no surgery or anesthesia. Current assessment at 0400: the client is mute and opens the eyes only to a loud voice; the arms and legs resist passive movement evenly through the range; no clonus at either ankle; pupils 4 mm and briskly reactive; skin is diaphoretic. Temperature 40.2 C (104.4 F), HR 132/min, RR 30/min, SpO2 95% on room air. Blood pressure was 176/102 mm Hg at 0200 and 88/50 mm Hg now. The client continues to mumble about hearing voices. Laboratory results are pending. ## Explanation Depressed arousal, uniform (lead-pipe) resistance to passive movement, hyperthermia to 40.2 C, and blood pressure swinging from 176/102 to 88/50 are the dangerous new findings after haloperidol escalation. Absent clonus, reactive mid-size pupils, and no serotonergic drug or anesthetic exposure argue against serotonin syndrome and malignant hyperthermia, and the resolved dystonia, admission agitation, and ongoing hallucinations are explained by earlier events or the psychiatric illness. ## In-depth explanation Quick answer Select reduced arousal, even resistance to passive movement, temperature 40.2 C, and the blood pressure swing from 176/102 to 88/50. Why this is correct After rapid dose escalation of a high-potency dopamine antagonist, the combination of altered consciousness, lead-pipe rigidity, hyperthermia, and autonomic lability is a medical emergency. The rigidity is described as uniform resistance through the range, which is the lead-pipe pattern rather than clonus. The blood pressure trend, not a single value, shows autonomic instability. Easy analogy or mental picture Imagine a thermostat and a brake both failing at once: temperature climbs, muscles lock, and blood pressure swings because the dopamine signal that regulates all three has been blocked. Memory hook NMS is slow and stiff (lead-pipe, days); serotonin syndrome is fast and twitchy (clonus, hours). NCLEX decision rule When a client on an antipsychotic develops fever, first compare the motor pattern and exposure history: uniform rigidity with dopamine-blocker exposure points to NMS; clonus with serotonergic exposure points to serotonin syndrome; anesthetic exposure points to malignant hyperthermia. Why the other choices are wrong No clonus and pupils 4 mm and reactive are tempting because they are neuromuscular and eye findings, but they are the negative findings that separate NMS from serotonin syndrome (clonus, mydriasis). No surgery or anesthesia excludes malignant hyperthermia as the trigger. The neck spasm was acute dystonia that has already resolved with treatment. Shouting and pacing on admission and hearing voices are features of the psychosis being treated, not of the new syndrome. SpO2 95% is acceptable at present. References 1StatPearls: Neuroleptic Malignant Syndrome (NCBI Bookshelf)Core NMS features: hyperthermia, lead-pipe rigidity, altered mental status, and autonomic instability after dopamine antagonists 2StatPearls: Serotonin Syndrome (NCBI Bookshelf)Serotonin syndrome is distinguished by clonus, hyperreflexia, mydriasis, and serotonergic drug exposure ## Clinical scenario Case update Acute deterioration — A client receiving escalating haloperidol for acute psychosis becomes difficult to arouse with fever and rigidity. ## Key concepts - **Lead-pipe rigidity** — Uniform resistance to passive movement throughout the range of motion, characteristic of neuroleptic malignant syndrome. - **Autonomic instability** — Labile blood pressure, tachycardia, and diaphoresis caused by disrupted autonomic regulation. - **Clonus** — Rhythmic involuntary muscle contractions after sudden stretch, typical of serotonin toxicity rather than NMS. ## Related questions - [A client hospitalized for depression says, "My family would be better off without me." 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