Assessment after self-poisoning or self-injury

01Purpose and principlesWhat the assessment is for and the core concepts behind it.

Treat the body and person simultaneously. Establish airway, breathing, circulation, disability and exposure, obtain bedside glucose and monitoring, and identify time-critical antidotes or procedures. Ask what was taken or done, when, how much, formulation, co-ingestants and alcohol, but do not demand a detailed motive before analgesia or resuscitation. Retrieve packaging and prior prescriptions where safe. Contact toxicology support for uncertainty, high-risk substances, delayed effects or discordant symptoms.

Paracetamol requires timing discipline. A concentration before four hours after one acute ingestion cannot exclude later toxicity. Use the current UK nomogram and treatment pathway for a timed level, and do not apply simple nomogram logic to staggered or uncertain ingestion. Delayed presentation may warrant immediate acetylcysteine while information and results are obtained under toxicology guidance. Check liver tests, INR, renal function, acid-base status and serial tests according to timing and pathway. The antidote regimen and stopping criteria must follow current national toxicology advice.

Other poisons demand specific patterns. ECG helps detect sodium-channel blockade, QT or conduction disturbance. Paracetamol and salicylate concentrations are commonly indicated when exposure is possible, while glucose, electrolytes, renal and liver profiles, acid-base status and pregnancy testing are selected from the case. A standard urine drug screen has limited coverage and rarely directs emergency care. Activated charcoal is only for selected recent potentially toxic ingestions when the airway is protected and toxicology advice supports benefit.

Examine self-injury properly. Describe location, depth, contamination, neurovascular and tendon function, foreign body and infection risk; image or explore according to injury guidance. Assess strangulation, burns, head injury and sexual or domestic violence through their emergency routes. Provide local anaesthesia, wound closure, tetanus and antibiotics when ordinarily indicated. Use neutral language and ask what function the act served, recognising that relief, punishment, communication, dissociation and suicidal intent can coexist.

NICE recommends psychosocial assessment at the earliest opportunity by an appropriately skilled mental-health professional. Cover mental state, intent, planning, expected outcome, previous self-harm, substances, physical health, relationships, trauma, housing, finance, safeguarding, strengths and preferred help. Do not use a scale or low-risk category to decide discharge. Share the formulation across physical and mental-health teams, reconcile medicines and limit supply where overdose access is relevant, then arrange aftercare according to need.

Key points

Begin with ABCDE, observations, glucose, consciousness, ECG and focused exposure or injury history; call toxicology, trauma or surgical support according to physiology and substance.
Record substance, preparation, dose, time, pattern, co-ingestants, alcohol, body weight, symptoms, treatment and available packaging without delaying resuscitation.
For a single acute paracetamol ingestion, interpret a timed concentration from at least four hours against the current UK treatment pathway; earlier levels cannot exclude toxicity.
Use current toxicology guidance for acetylcysteine, decontamination, serial concentrations and discharge because staggered, uncertain and modified-release ingestions need different logic.
Assess wounds for bleeding, tendon, nerve and vascular injury, foreign body, infection, tetanus and safeguarding; manage pain and repair to the same standard as other injuries.
Offer psychosocial assessment at the earliest safe opportunity and do not delay automatically until all medical treatment is complete if the person can participate.
Explore what happened before, during and after, expected lethality, suicidal intent, the function of self-harm, rescue, regret, current thoughts, means and social context.
Identify abuse, exploitation, dependants, accommodation and access to medicines; use consented collateral information and necessary safeguarding sharing.
Before discharge, complete physical and psychosocial plans, means safety, medicines review, accessible contacts and named aftercare, with active response to missed contact.

02Indications, selection and cautionsWhen it is useful, when urgency changes and important limitations.

Toxic syndrome

Abnormal consciousness, pupils, temperature, sweating, bowel activity, rigidity, clonus, ECG or acid-base status suggests a specific poison or withdrawal pattern.

Delayed-toxicity risk

A sustained-release or long-acting exposure can worsen after initial stability and requires the observation and serial testing defined by toxicology guidance.

High-intent minor injury

Limited tissue damage follows interruption or low technical success despite suicide planning, concealment or expectation of death.

Non-suicidal self-injury function

The act regulates distress, dissociation or self-punishment without intended death, while accidental lethality and later suicide risk still require care.

Unsafe discharge context

Persistent intent, available means, abuse, homelessness, intoxication, medical uncertainty or absent aftercare prevents a reliable discharge plan.

Red flags requiring action

Unknown or staggered paracetamol ingestion, presentation more than eight hours after a potentially toxic dose or unreliable timing requires immediate toxicology-guided action rather than waiting for a routine concentration.
Modified-release products, multiple substances, sustained-release toxicity, body-packing, tricyclic ingestion, opioids or toxic alcohols can deteriorate after an initially reassuring appearance.
Ligature or strangulation can cause delayed airway, vascular and neurological complications despite minimal external injury and needs an appropriate emergency pathway.
A medically minor wound can accompany high suicidal intent, extensive planning or abuse; injury severity must not determine psychosocial urgency.
Do not use risk scores to predict suicide or decide discharge, and do not withhold physical analgesia or treatment because harm was self-inflicted.

03Method and interpretationA systematic approach to the test and its findings.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Immediate physiological assessmentFirst step
Why
Identify airway, respiratory, circulatory, neurological, glucose and temperature threats requiring emergency treatment.
Interpretation and limitations
Physiology determines urgency and care setting. Initial stability does not exclude delayed toxicity from long-acting or modified-release agents.
02
Exposure-specific toxicology work-up
Why
Measure relevant concentrations, ECG, electrolytes, organ function and acid-base effects and guide antidote or observation.
Interpretation and limitations
Timing and formulation determine meaning. Use current national toxicology guidance rather than a universal panel or urine screen.
03
Injury assessment
Why
Detect bleeding, tendon, nerve, vascular, airway, internal, infection and safeguarding consequences.
Interpretation and limitations
Document examination limitations and escalate high-risk anatomy or strangulation even when external appearance is modest.
04
Psychosocial assessmentPreferred
Why
Understand intent, function, mental state, needs, context, strengths, safeguarding and preferred treatment.
Interpretation and limitations
Complete when participation is possible and do not substitute a predictive scale. Medical severity and suicidal intent are separate dimensions.
05
Medicines and means review
Why
Identify current prescriptions, access, adherence, toxicity, duplicate supply and opportunities for safer dispensing.
Interpretation and limitations
Limit or supervise supply collaboratively when relevant while preserving necessary treatment and avoiding punitive discontinuation.

04Clinical next stepsHow the result changes management or prompts escalation.

01Poisoning responseStabilise and use substance-specific guidanceFirst stepRecent self-poisoning is known or clinically suspected.

1Use ABCDE, glucose, cardiac monitoring and focused substance, formulation, dose, time and co-ingestant history.
2Contact toxicology support and obtain timed concentrations, ECG and laboratory tests that change antidote, observation or enhanced-elimination decisions.
3Treat without delay when the pathway indicates, trend delayed effects and transfer the physical plan alongside psychosocial care.

02Self-injury responseTreat injury and preserve dignityCutting, burning, ligature, blunt trauma or another self-inflicted injury is present.

1Control bleeding and assess high-risk anatomy, neurovascular and tendon function, strangulation, burns, head injury and pain.
2Provide imaging, exploration, repair, tetanus, antibiotics and specialist referral using ordinary injury standards.
3Document exact findings and safeguarding concerns and offer psychosocial assessment without requiring the wound to prove intent.

03Integrated dischargeComplete physical and psychosocial safetyAcute treatment is complete enough for the next care setting to be considered.

1Confirm toxicology or injury observation and result criteria, medicine changes, capacity, current intent, means and accommodation.
2Create a collaborative safety and aftercare plan with named contacts, supply arrangements and support for dependants or safeguarding.
3Communicate directly with the receiving clinician and respond actively to missed follow-up rather than relying on a risk category.

05Risks, monitoring and follow-upComplications, safety checks and further assessment.

Trend observations, ECG, consciousness, glucose, acid-base status and organ markers for the interval required by the specific exposure.
Reassess mental state, intent and capacity after sobriety, antidote treatment, sleep, analgesia and new collateral information.
Review wound perfusion, neurology, tendon function, infection and pain and provide clear return precautions for delayed complications.
Confirm that prescriptions, duplicate supplies and household medicines were addressed and that essential treatment remains accessible safely.
Arrange aftercare at the urgency indicated by needs, including contact within 48 hours when NICE identifies ongoing safety concerns.

06Special situationsVariants, exceptions and circumstances that change the usual approach.

Four hours matters

A paracetamol concentration drawn too early after one acute ingestion can look reassuring before absorption is complete and cannot exclude treatment need.

Severity dimensions separate

Tissue damage, toxic dose, suicidal intent and future need overlap but are not interchangeable and each requires explicit assessment.

Analgesia is ordinary care

Pain relief, local anaesthetic and respectful wound treatment should not be withheld because an injury was self-inflicted.

Assessment can run in parallel

Psychosocial work may begin during medical care when the person can participate, without delaying antidote, surgery or physiological monitoring.

Urine screens are narrow

A positive result does not prove causation or impairment, and a negative panel does not exclude many clinically important substances.

07Common pitfallsFrequent interpretation and management errors.

01
Using an early paracetamol concentration to exclude toxicity after an acute ingestion.
02
Applying a single-ingestion nomogram to staggered or uncertain timing.
03
Assuming initial normal observations exclude delayed-release or long-acting toxicity.
04
Providing poorer analgesia or wound repair because injury was self-inflicted.
05
Inferring suicidal intent solely from wound depth or tablet quantity.
06
Delaying all psychosocial contact until every medical result is normal despite safe participation.
07
Using a risk scale to decide discharge or access to aftercare.