Acute psychosis

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• The Functional vs. Organic Divide: Acute psychosis—defined as a loss of contact with reality, disorganized thinking, and hallucinations—is broadly divided into "functional" (primary psychiatric, e.g., schizophrenia) and "organic" (medical/toxicologic) etiologies.
• Functional (Psychiatric) Pathophysiology: Primary psychotic disorders like schizophrenia are driven by complex neurochemical imbalances (primarily dopamine and glutamate pathways) that develop over weeks to months, typically presenting in younger patients (<40 years old).
• Organic (Medical/Toxicologic) Pathophysiology: Organic psychosis or substance-induced delirium occurs when an acute medical illness, systemic infection, or chemical exposure disrupts global cerebral metabolism. Sympathomimetics (cocaine, methamphetamines), hallucinogens (PCP), or sudden withdrawal syndromes (alcohol) cause acute neurotransmitter surges or receptor down-regulation, precipitating an acute-onset altered mental state that mimics functional psychosis.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Immediate Safety & Stabilization: Ensure the safety of the patient and ED staff. Utilize verbal de-escalation first. Place the patient in a secure room, and have security and nursing staff prepare to search the patient for weapons and place them in a hospital gown.
• Chemical Sedation: If the patient exhibits severe uncontrolled agitation or violence, immediate chemical sedation is required.
• First-line agents: Intramuscular (IM) benzodiazepines (e.g., midazolam or lorazepam).
• Alternative/Adjunctive agents: Typical antipsychotics (e.g., haloperidol), atypical antipsychotics, or IM/IV ketamine.
• Mandatory Bedside Testing: Obtain a stat point-of-care (POC) blood glucose on every patient presenting with altered mental status or psychotic behavior to immediately rule out hypoglycemia.
• Monitoring: Once sedated, patients require continuous cardiorespiratory monitoring to observe for respiratory depression or hemodynamic instability caused by the underlying etiology or the administered sedatives.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

• Top "Can't-Miss" Mimics:
• Anticholinergic Toxicity: Presents with confusion, agitation, visual hallucinations, dry skin/mouth, urinary retention, tachycardia, and fever.
• Acute Alcohol Withdrawal / Delirium Tremens: Manifests with abnormal vital signs, tremors, and hallucinations secondary to sudden cessation of chronic alcohol intake.
• CNS Infection (Meningitis/Encephalitis): Can present purely with acute behavioral changes, fever, and confusion.
• Acute Mania: Can feature hallucinations, grandiosity, and pressured speech mimicking acute schizophrenia; often triggered by medications.
• Prioritized Diagnostic Workup:
• Tier 1: POC Blood Glucose, vital signs assessment, and a comprehensive physical exam to hunt for toxidromes or hidden trauma.
• Tier 2: Laboratory evaluation directed by the H&P to rule out infectious, endocrine (e.g., thyrotoxicosis), or toxicologic (e.g., sympathomimetics) drivers.
• Tier 3: Non-contrast head CT and/or lumbar puncture if focal neurologic deficits, fever, or signs of head trauma are present.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

• The Physical Exam / Vital Sign Paradigm: The most important "visual" diagnostic tool is the patient's presentation.
• Functional Psychosis: Expect a normal physical examination and normal vital signs.
• Organic Psychosis: Expect an abnormal physical examination (e.g., toxidromes, nystagmus, focal deficits) and abnormal vital signs (tachycardia, hypertension, hyperthermia).
• Neuroimaging (CT Head): ACEP 2017 guidelines state that brain imaging for patients presenting with new-onset psychosis without focal neurologic deficits should be guided by an individual patient risk assessment. Routine scanning of all psychiatric patients is not mandated, but a low threshold should be maintained for older patients or those with sudden, unexplained behavioral changes.

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

• The Hallucination Distinction Rule:
• Auditory Hallucinations: Highly specific for functional psychiatric disorders (e.g., schizophrenia).
• Visual or Tactile Hallucinations: Highly specific for organic medical etiologies or delirium.
• The Delirium Triage Screen (DTS): Used to rapidly rule out organic delirium in less than 20 seconds. It consists of two steps:

1. Measuring the level of consciousness via the Richmond Agitation Sedation Scale (RASS).
2. Testing for inattention by having the patient spell "LUNCH" backwards.

• Age of Onset Criteria: Functional psychiatric illness typically presents gradually over weeks to months in patients <40 years old. Acute onset in a patient >50 years old is an organic medical emergency until proven otherwise.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

• The Gatekeeper Error (Premature Closure): Pitfall: Assuming a combative or hallucinating patient merely has a psychiatric flare-up without performing a thorough medical clearance. Critical Action: Emergency providers are the gatekeepers; once a patient is funneled into an inpatient psychiatric unit, organic conditions become exceedingly difficult to identify and treat, significantly increasing mortality risk.
• The Neuroleptic Trap in Alcohol Withdrawal: Pitfall: Using a neuroleptic (antipsychotic) as the sole agent to treat a patient in acute psychotic agitation from alcohol withdrawal. Critical Action: While neuroleptics are useful for acute schizophrenic agitation, they lower the seizure threshold and are inappropriate as monotherapy for alcohol withdrawal; benzodiazepines are required.
• Delaying the Medical Screening Exam: Pitfall: Delaying the medical screening exam of a severely agitated or psychotic patient to wait for registration or preauthorization.

7. MCQ MASTERCLASS (Written Exam Tips)

• Buzzwords: "Visual hallucinations," "acute onset," "abnormal vital signs," "older patient."
• Diagnosis: Organic Psychosis/Delirium (Medical/Toxicologic etiology).
• Buzzwords: "Auditory hallucinations," "gradual onset over weeks," "normal physical exam."
• Diagnosis: Functional Psychosis (Schizophrenia).
• Common Distractor: A 25-year-old female presents with severe agitation, visual hallucinations, tachycardia, hypertension, and a fever. An option suggests "Acute schizophrenia." Differentiate: Schizophrenic patients classically experience auditory hallucinations and have normal vital signs. Visual hallucinations paired with autonomic instability (fever, tachycardia) point to an organic toxidrome, specifically anticholinergic poisoning.
• Pharmacology Tip: If a question asks which medication is appropriate for rapid tranquilization of an intoxicated known schizophrenic, select the neuroleptic agent. However, if the psychosis is driven by an anticholinergic overdose or isolated alcohol withdrawal, neuroleptics as sole agents are contraindicated.

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

• The Opening Salvo: "My immediate priority is the safety of the patient and the ED staff. I will utilize verbal de-escalation, call for security, ensure the patient is searched for weapons, and place them in a secure room. Simultaneously, I will assess their ABCs and obtain a stat point-of-care glucose to rule out hypoglycemia as a cause of their altered mental status."
• Articulating the Workup: "Because this patient is over 50 years old, has an acute onset of symptoms, and is experiencing visual hallucinations, this presentation strongly suggests a life-threatening organic etiology rather than a functional psychiatric disorder. I will perform a comprehensive physical exam searching for toxidromes, infection, or trauma, and order a non-contrast head CT per ACEP guidelines."
• Managing the Agitation: "The patient is becoming violent and is a danger to themselves and staff. I will order physical restraints and immediate chemical sedation with intramuscular benzodiazepines or an atypical antipsychotic. Once the patient is chemically sedated, I will place them on continuous cardiac monitoring and complete my medical clearance evaluation before consulting psychiatry."