AIM · FINAL YEAR MBBS · MS MODULE · STUDENT MEMORY SUPPORT
Acute Poisoning, Toxicological Emergencies & Envenomation
High-yield reinforcement after AIM Learning Material · KMU-aligned quick revision
1. High-Yield Flashcards
Tap a question to reveal its answer.
What is the first priority in an unstable patient with suspected poisoning?
ABCDE stabilization before exact poison identification.
Which bedside tests are early priorities in significant poisoning?
Capillary glucose and 12-lead ECG.
What is the main danger of coma with absent protective airway reflexes?
Aspiration and inadequate ventilation.
Which clinical combination suggests organophosphate poisoning?
Bronchorrhoea, salivation, miosis and muscle fasciculations.
What is the useful clinical endpoint of atropine in organophosphate poisoning?
Improved ventilation and clearance of bronchial secretions.
What finding helps distinguish anticholinergic from sympathomimetic toxicity?
Dry skin favours anticholinergic; sweating favours sympathomimetic toxicity.
Why may a patient with paracetamol overdose initially appear well?
NAPQI-mediated hepatotoxicity may develop after an initially silent period.
When is a timed paracetamol concentration interpreted with the treatment nomogram?
At least 4 hours after a single acute ingestion with a reliable ingestion time.
What is the principal action of N-acetylcysteine in paracetamol poisoning?
Replenishes glutathione to detoxify NAPQI.
Why is flumazenil often avoided in mixed or chronic benzodiazepine exposure?
It can precipitate seizures.
What immediate measures help control stimulant-associated hyperthermia?
Benzodiazepine sedation, active cooling and appropriate supportive fluids.
What two key features suggest serious methanol toxicity?
High-anion-gap metabolic acidosis and visual disturbance.
Which targeted drug prevents formation of toxic methanol metabolites?
Fomepizole inhibits alcohol dehydrogenase.
Why can pulse oximetry be misleading in carbon monoxide poisoning?
Standard SpO₂ does not reliably distinguish carboxyhaemoglobin.
When may antivenom be indicated after snakebite?
Systemic or significant progressive local envenomation under local protocols.
What are important contraindications to gastric lavage?
Unprotected airway, caustic ingestion and high-aspiration-risk hydrocarbons.
2. Mnemonics
First-hour poisoning assessment
ABCDE
Airway → Breathing → Circulation → Disability (including glucose) → Exposure/decontamination.
Organophosphate secretions
SLUDGE
Salivation, Lacrimation, Urination, Diarrhoea, Gastrointestinal symptoms, Emesis; bronchorrhoea and respiratory weakness remain the immediate dangers.
Dangerous snake envenomation
B-N-R
Bleeding/coagulopathy → Neurotoxicity (ptosis, bulbar or respiratory weakness) → Renal injury. These features warrant urgent assessment.
3. Memory Tables
Toxidromes that look similar
| Finding | Anticholinergic | Sympathomimetic |
|---|---|---|
| Skin | Dry, flushed | Sweaty |
| Pupils | Dilated | Dilated |
| Mental state | Delirium/agitation | Agitation |
| Typical complication | Hyperthermia from impaired sweating | Hyperthermia from excess activity |
Common poison–targeted treatment links
| Exposure | Targeted care | Important caution |
|---|---|---|
| Paracetamol | N-acetylcysteine | May be initially asymptomatic |
| Organophosphates | Atropine ± pralidoxime | Protect ventilation; treat bronchorrhoea |
| Methanol | Fomepizole; dialysis if severe | Visual toxicity/acidosis |
| Carbon monoxide | 100% oxygen | Normal SpO₂ may mislead |
| Snake envenomation | Indicated antivenom | Monitor for anaphylaxis |
4. Rapid Revision Points — Last-Minute Revision
- Stabilize ABCDE, treat hypoglycaemia and obtain an ECG before waiting for toxicology screening.
- A normal neurological examination initially does not exclude delayed paracetamol hepatotoxicity.
- Atropinization is guided chiefly by improving bronchial secretions and ventilation.
- Pralidoxime may help in appropriate organophosphate exposure before enzyme ageing.
- Flumazenil is hazardous in chronic benzodiazepine use, seizure risk or mixed overdose.
- Stimulant agitation with severe hyperthermia risks rhabdomyolysis and arrhythmia.
- Methanol poisoning may cause delayed visual symptoms with high-anion-gap acidosis.
- Standard SpO₂ can be falsely reassuring in carbon monoxide exposure.
- Gastric lavage is exceptional, not routine; airway protection and contraindications matter.
- Suspected envenomation requires serial respiratory, coagulation and renal assessment.
- Intentional self-poisoning requires psychosocial assessment and a safe follow-up plan.
5. Clinical Memory Hooks
Farmer with bronchorrhoea, wheeze and fasciculations → Organophosphate poisoning → atropine, airway support ± pralidoxime
Well-appearing patient after significant paracetamol ingestion → Delayed hepatotoxicity → timed level and indicated NAC
Adulterated alcohol followed by blurred vision and acidosis → Methanol metabolites → fomepizole and urgent escalation
Whole family unwell after indoor heater use despite normal SpO₂ → Carbon monoxide exposure → high-concentration oxygen and co-oximetry
Snakebite with ptosis and difficulty swallowing → Neurotoxic envenomation → respiratory vigilance and indicated antivenom
6. Starred High-Yield Exam Points
- ⭐ Airway protection and ventilation precede gastrointestinal decontamination.
- ⭐ N-acetylcysteine prevents progression of toxic paracetamol liver injury when used appropriately.
- ⭐ Organophosphate respiratory secretions improve with atropine; muscle weakness may need oxime therapy and ventilatory support.
- ⭐ Dry delirium differentiates anticholinergic toxicity from the sweaty sympathomimetic pattern.
- ⭐ Flumazenil can precipitate seizures in benzodiazepine dependence or mixed overdose.
- ⭐ Fomepizole blocks toxic methanol metabolism; serious acidosis may need dialysis.
- ⭐ Carbon monoxide poisoning cannot be excluded by routine pulse oximetry.
- ⭐ Antivenom is for clinically significant envenomation, not bite marks alone.