Agitated Delirium Versus Worsening Psychosis on an Inpatient Unit

This is delirium, most plausibly multifactorial: clozapine-related complications (constipation/ileus with poor intake; possible NMS-spectrum reaction), anticholinergic/medication burden, infection (UTI), and ciprofloxacin interaction (a CYP1A2 inhibitor that can raise clozapine levels substantially).

Distinguishing features from primary psychosis:

• Acute onset with fluctuating course and altered arousal/attention - psychosis alone does not impair attention and level of consciousness.
• Autonomic instability (tachycardia, fever, diaphoresis, hypertension) points to a medical/toxic cause, not a primary psychiatric exacerbation.
• Disorientation and incoherent speech in a previously oriented patient.
• Psychosis typically has preserved alertness and a coherent (if delusional) narrative.

The combination of fever, rigidity/tremor, autonomic instability, and recent clozapine with a CYP1A2 inhibitor should also raise concern for NMS (though clozapine-associated NMS is uncommon) and for clozapine toxicity. Delirium is the syndromic diagnosis; the workup must identify the cause.

Do not give the PRN haloperidol - antipsychotics in delirium (especially with possible NMS or in a patient already on clozapine) can worsen rigidity, lower seizure threshold, and prolong QTc; they are not first-line for agitated delirium.

Hold clozapine pending evaluation: it is contraindicated in the setting of suspected NMS, and levels may be rising due to ciprofloxacin. Also stop ciprofloxacin and switch to a non-CYP1A2-inhibiting antibiotic if a UTI is confirmed.

Immediate workup:

• Stat clozapine level, CBC with ANC (agranulocytosis risk), CK, CMP, TSH, UA/urine culture, ECG (QTc), blood gas, lactate, and imaging as indicated.
• Assess for constipation/ileus (abdominal exam, KUB) - a classic and potentially fatal clozapine complication.

Management:

• Nonpharmacologic first-line: reorientation, consistent staff, low stimulation, glasses/hearing aids, mobilization, sleep hygiene.
• Treat the underlying cause (hydration, electrolytes, antibiotics, bowel regimen).
• For agitation, low-dose atypical antipsychotic (e.g., quetiapine) or dexmedetomidine may be considered cautiously; avoid benzodiazepines as monotherapy in a patient with possible delirium (they worsen it) except when withdrawal is the cause.
• If NMS is suspected, supportive care, dantrolene/bromocriptine per severity, and avoid restarting clozapine until fully resolved.

Counsel that the change is medical, not a relapse of his psychiatric illness, and that the priority is identifying and treating the cause. Explain that several of his medications and a new antibiotic may be contributing and that some will be held.

Documentation should include:

• The time course and fluctuating mental status, vital signs, and the specific features supporting delirium.
• The medication review with the ciprofloxacin–clozapine interaction and rationale for holding clozapine and haloperidol.
• The differential (delirium, NMS, serotonin syndrome if applicable, anticholinergic toxicity, infection, metabolic).
• Capacity assessment if he is refusing care, and the surrogate decision-maker process.
• A safety plan (falls, aspiration, elopement) and re-assessment intervals.
• A plan to restart clozapine at the prior dose only after resolution and after confirming levels and ANC, with a clear monitoring schedule.