Psychiatric emergencies: the physical causes come first
The commonest serious error in a disturbed patient is assuming the cause is psychiatric.
A patient who is confused, frightened, agitated or behaving strangely presents a genuine diagnostic problem, and the way that problem is usually mishandled is consistent: the behaviour is treated as the diagnosis. The patient is labelled, sedated or referred, and the hypoxia, the hypoglycaemia, the sepsis or the withdrawal that produced the behaviour goes untreated.
So this chapter has one organising rule, and the rest follows from it: exclude the physical before you conclude the psychiatric. That is not defensive medicine. Delirium is a medical emergency with a mortality comparable to a heart attack, and it presents exactly like a psychiatric crisis.
🩺 Where this lives: An elderly patient becomes agitated on a surgical ward overnight, pulls out a cannula, and is described in the notes as "confused and aggressive". The differential that matters is not psychiatric — it is urinary retention, pain, constipation, hypoxia, infection, or a drug given earlier that day. Sedating this patient without examining them relieves the ward and leaves the cause running. Delirium in hospital is common, frequently missed, and independently associated with longer stays, functional decline and death.
💡 A note on scope. This chapter covers risk assessment and management. It deliberately contains no detail about methods of self-harm, which is clinically unnecessary for the decisions described here. It also gives no drug doses — rapid tranquillisation is protocol-driven and carries real airway and cardiovascular risk. Take those from your local protocol.
Physical causes first
Three features point strongly toward an organic cause: an acute onset, a fluctuating course, and clouded consciousness with inattention. Primary psychotic illness usually develops over a longer period with a clear sensorium. And while auditory hallucinations occur in both, prominent visual hallucinations should always raise the suspicion of delirium — including withdrawal states.
THE MINIMUM ASSESSMENT IN ANY DISTURBED PATIENT
IMMEDIATELY
GLUCOSE — hypoglycaemia causes agitation, aggression
and confusion, and reverses in minutes
Oxygen saturation
Temperature
Pulse, blood pressure, respiratory rate
THEN
Full history from the patient AND from someone who
knows them — the collateral history is often the
whole diagnosis
Medication review, including what was recently started,
stopped or missed
Alcohol and substance history, including timing of the
last drink
Physical examination, including neurological
Bloods, cultures and imaging as indicated
ASK SPECIFICALLY ABOUT
Pain · urinary retention · constipation
These are the three reversible causes of agitation in
older patients that are most often overlooked, and none
of them requires a test to find.
Assessing risk of self-harm and suicide
HOW TO ASK, AND WHAT TO LISTEN FOR
Ask directly and unhurriedly, in private. Move from the
general to the specific: how they have been feeling, then
whether life has felt not worth living, then whether they
have thought of ending it, then whether they have made
any plan.
WHAT INCREASES CONCERN
Clear intent to die, rather than to escape distress
A plan, and steps already taken toward it
Precautions against being found
Continuing intent, or regret at having survived
Access to means
Hopelessness — a stronger predictor than sadness
Recent discharge from psychiatric care
PROTECTIVE FACTORS matter too — dependants, supportive
relationships, engagement with treatment, stated reasons
for living — but they never cancel out active intent.
DOCUMENT what was asked and what was answered, in the
patient's own words where possible.
CRUCIALLY: risk fluctuates. An assessment describes this
moment, not the coming week, which is why follow-up and
a safety plan matter more than a category label.
Two evidence-based points worth stating plainly. Asking about suicide does not increase risk — the fear that it "plants the idea" is unfounded, and the question is more often experienced as a relief. And restricting access to means is among the most effective interventions available, which is why a practical conversation about what is in the house is part of the plan rather than an afterthought.
After self-harm
🔍 What must happen before discharge
Treat the physical injuryFully, and with the same care as any other patient. People who have self-harmed receive measurably worse physical care in some settings, and that is a failure of the service rather than a clinical necessity.
Then assessEvery episode of self-harm needs a psychosocial assessment before discharge — not just medical clearance. The overdose or injury is the presenting event; the reason for it is the diagnosis.
Self-harm is itself a risk factorA previous episode is among the strongest predictors of eventual suicide, even when the current episode looked medically minor. Low lethality does not mean low risk.
CapacityA patient wishing to leave before assessment needs a capacity assessment, and mental health legislation may apply. Do not simply record "refused" and let them walk out.
SafeguardingConsider dependants at home, and the possibility of abuse or coercion contributing to the presentation.
The planFollow-up arranged, means restricted where possible, and the patient and family told specifically what to do if things worsen.
The acutely agitated patient
💡 Exam angle: the correct sequence is environment and communication before medication, oral before parenteral, and medication only after physical causes have been considered. Questions offering immediate intramuscular sedation as the first step in an agitated elderly patient are testing whether you will look for retention, pain, hypoxia or withdrawal first. Note also that sedation carries genuine risk — respiratory depression, aspiration, falls, cardiovascular events — so a sedated patient requires monitoring, not just a quieter ward.
Drug-related emergencies
TELLING THEM APART, AND WHY IT MATTERS
NEUROLEPTIC MALIGNANT SYNDROME
Trigger: antipsychotics (or withdrawal of dopaminergic
drugs in Parkinson's disease)
Onset: DAYS
Tone: LEAD-PIPE RIGIDITY, hyporeflexia
Plus: hyperthermia, autonomic instability, raised
creatine kinase, risk of rhabdomyolysis and renal
failure
Action: stop the drug, cool, resuscitate, critical care
SEROTONIN SYNDROME
Trigger: serotonergic drugs, often a recent addition —
SSRIs, tramadol, linezolid, triptans, and others
Onset: HOURS
Tone: CLONUS and HYPERREFLEXIA, especially lower limbs
Plus: agitation, hyperthermia, diarrhoea, dilated pupils
Action: stop the drug, supportive care, critical care
The discriminator is TIME and TONE: days and rigidity
versus hours and clonus.
ALCOHOL WITHDRAWAL
Escalates from tremor and sweats through seizures to
DELIRIUM TREMENS, which carries significant mortality.
Treat with benzodiazepines by protocol.
GIVE THIAMINE — and give it BEFORE glucose in a
malnourished or alcohol-dependent patient, because a
glucose load can precipitate Wernicke's
encephalopathy in thiamine deficiency.
Wernicke's: confusion, ataxia, ocular signs. Untreated
it may progress to irreversible Korsakoff syndrome.
💡 Exam angle: thiamine before glucose in a dependent or malnourished patient is asked repeatedly and is genuinely important. Glucose metabolism consumes thiamine; giving a glucose load to a thiamine-deficient patient can precipitate Wernicke's encephalopathy. In practice, do not withhold glucose from a hypoglycaemic patient — give both, with thiamine first or alongside.
Clinical reasoning: four presentations
🔍 Case 1 — the "aggressive" patient
PresentationAn 82-year-old man, two days after hip surgery, becomes agitated overnight, tries to climb out of bed and pushes a nurse away. The night team is asked to prescribe sedation.
TrapTreating the behaviour rather than looking for its cause.
ReasoningThis is delirium until proven otherwise. The reversible causes in this exact situation are urinary retention, pain, constipation, hypoxia, infection and recently administered drugs — none of which needs a specialist to find.
AnswerCheck glucose, saturations and temperature; palpate for a full bladder and scan it; assess pain; review the drug chart; look for infection. Treat what you find. Consider sedation only if he remains at risk after that, and monitor him if you use it.
🔍 Case 2 — the minor overdose
PresentationA 23-year-old took a small overdose after a relationship breakdown. Bloods are reassuring and she is medically fit. She is calm, apologetic, says it was impulsive, and asks to go home. The department is busy.
The distractorMedical fitness reading as readiness for discharge.
ReasoningMedical clearance is not assessment. Self-harm is among the strongest predictors of later suicide, and low medical lethality does not indicate low risk. Her current calm may reflect resolution — or relief at a decision made.
AnswerPsychosocial assessment before discharge, including direct questions about intent and ongoing thoughts. Arrange follow-up, discuss restricting access to means, and involve mental health services per local pathway.
🔍 Case 3 — days versus hours
PresentationA patient on a long-standing antipsychotic develops, over three days, fever, marked generalised rigidity, fluctuating consciousness and labile blood pressure. Creatine kinase is markedly raised.
ReasoningNeuroleptic malignant syndrome. The slow onset and lead-pipe rigidity distinguish it from serotonin syndrome, which develops over hours with clonus and hyperreflexia.
AnswerStop the antipsychotic, cool actively, resuscitate with attention to rhabdomyolysis and renal function, and involve critical care. Time course and tone are the discriminators.
🔍 Case 4 — the order of drugs
PresentationA malnourished man with alcohol dependence is brought in drowsy and confused. Capillary glucose is 2.4 mmol/L. A colleague draws up intravenous glucose.
Key clueAlcohol dependence with malnutrition — thiamine deficiency is likely.
ReasoningGlucose metabolism consumes thiamine. A glucose load in a thiamine-deficient patient can precipitate Wernicke's encephalopathy, which may become irreversible.
AnswerGive thiamine first or alongside the glucose — but do not withhold glucose from a hypoglycaemic patient while waiting. Then assess for withdrawal and treat it by protocol, and look for the other causes of his confusion.
Commonly confused
Confusion
The distinction
Why it matters
Delirium vs primary psychosis
Acute, fluctuating, clouded consciousness
Delirium is a medical emergency with an untreated cause.
Visual vs auditory hallucinations
Prominent visual ones suggest an organic cause
Redirects the whole assessment.
Agitation vs its cause
Retention, pain, hypoxia and withdrawal cause it
Sedation treats the ward, not the patient.
Medical clearance vs assessment
Psychosocial assessment is required before discharge
The reason for the act is the diagnosis.
Low lethality vs low risk
Previous self-harm strongly predicts later suicide
A "minor" overdose is not a minor presentation.
NMS vs serotonin syndrome
Days and rigidity versus hours and clonus
Different triggers, same need for critical care.
Glucose vs thiamine first
Thiamine first or alongside in dependence
Glucose alone can precipitate Wernicke's.
Rapid revision
MUST-KNOW FACTS
1. Exclude PHYSICAL causes before concluding a psychiatric one.
2. Delirium is a medical emergency and is frequently missed.
3. Delirium: ACUTE onset, FLUCTUATING course, CLOUDED consciousness.
4. Prominent VISUAL hallucinations suggest an organic cause.
5. Check GLUCOSE, saturations and temperature in every disturbed patient.
6. Pain, urinary retention and constipation are the most overlooked causes
of agitation in older patients.
7. Collateral history is often the whole diagnosis.
8. ASK DIRECTLY about suicide — it does not increase risk.
9. Intent, planning, steps taken and precautions against discovery raise concern.
10. Previous self-harm is among the strongest predictors of later suicide.
11. Hopelessness predicts more strongly than sadness.
12. Risk scores do not predict individuals and never replace assessment.
13. RESTRICTING ACCESS TO MEANS is among the most effective interventions.
14. Risk fluctuates — follow-up and a safety plan matter more than a label.
15. Every episode of self-harm needs psychosocial assessment before discharge.
16. Low medical lethality does NOT mean low risk.
17. Treat the physical injury fully and without judgement.
18. Agitation: safety, then de-escalation, then treat the cause, then medication.
19. Offer ORAL medication before parenteral; monitor after sedation.
20. Restraint is a last resort, time-limited and documented.
21. NMS: antipsychotics, DAYS, lead-pipe RIGIDITY, raised CK.
22. Serotonin syndrome: serotonergic drugs, HOURS, CLONUS and hyperreflexia.
23. Alcohol withdrawal: benzodiazepines plus THIAMINE.
24. THIAMINE before or alongside glucose in dependence or malnutrition.
25. Wernicke's: confusion, ataxia, ocular signs — treat urgently.
💡 Exam angle: the reliable threads are (a) delirium presenting as a psychiatric emergency, (b) agitation having a treatable physical cause, (c) psychosocial assessment before discharge after self-harm, (d) NMS versus serotonin syndrome by time and tone, and (e) thiamine before glucose. The through-line of this chapter is the same as the rest of the stream, applied to behaviour: the obvious interpretation is frequently the wrong one, and the cost of accepting it is borne by the patient.
Syllabus points
Excluding physical causes before psychiatric ones
Delirium versus primary psychosis
The minimum assessment in a disturbed patient
Reversible causes of agitation in older patients
Assessing risk of self-harm and suicide
Asking directly, and what raises concern
What must happen before discharge after self-harm
Managing agitation: de-escalation before medication
Neuroleptic malignant syndrome
Serotonin syndrome and how it differs
Alcohol withdrawal, thiamine and Wernicke's
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