Membership of the Joint Dental Faculties (MJDF) Human Disease, Pharmacology and Medical Emergencies Flashcards

24 sample cards from the Human Disease, Pharmacology and Medical Emergencies deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. Why must metronidazole never be taken with alcohol, and why is fluconazole used cautiously with warfarin?

   Metronidazole inhibits aldehyde dehydrogenase, causing a disulfiram-like reaction (flushing, vomiting) with alcohol. Fluconazole inhibits cytochrome P450 (CYP2C9), reducing warfarin metabolism and dangerously raising the INR.

2. Classify adverse drug reactions into Type A and Type B with one example of each.

   Type A (Augmented): dose-related, predictable extension of pharmacology, e.g. NSAID gastric bleeding. Type B (Bizarre): unpredictable, not dose-related, often immunological, e.g. penicillin anaphylaxis.

3. Distinguish a true penicillin allergy from common non-allergic intolerance, and what cross-reactivity exists with cephalosporins?

   True allergy is an immune-mediated reaction (rash, urticaria, angio-oedema, anaphylaxis); GI upset alone is intolerance, not allergy. Cross-reactivity with cephalosporins is low (~1-3%) but they are still avoided in severe penicillin allergy.

4. List the clinical features that define anaphylaxis as opposed to a simple allergic reaction.

   Anaphylaxis = sudden onset with Airway compromise (stridor, swelling), Breathing difficulty (wheeze, hypoxia) and/or Circulation collapse (hypotension, tachycardia), usually with skin changes. It is life-threatening and needs immediate adrenaline.

5. State the adult dose, concentration and route of adrenaline for anaphylaxis in the dental setting.

   Adrenaline $500$ micrograms ($0.5$ mL of 1:1000) intramuscularly into the anterolateral thigh, repeated every 5 minutes if no improvement. Call 999, give high-flow oxygen and lay the patient flat with legs raised.

6. What is the most widely used dental local anaesthetic, its mechanism of action, and its maximum safe dose?

   Lidocaine. It blocks voltage-gated sodium ($\ce{Na+}$) channels, preventing nerve depolarisation and impulse conduction. Maximum dose is about $4.4$ mg/kg (commonly cited max $\approx 300$ mg, i.e. ~7 cartridges of 2% with adrenaline).

7. Calculate the milligrams of lidocaine in one 2.2 mL cartridge of 2% lidocaine.

   A 2% solution contains $20$ mg/mL, so $20 \times 2.2 = 44$ mg of lidocaine per cartridge.

8. Why is adrenaline added to local anaesthetic solutions, and which alternative LA is amide-based but used without a vasoconstrictor (e.g. in pregnancy/cardiac concern)?

   Adrenaline causes local vasoconstriction, prolonging anaesthesia, reducing bleeding and slowing systemic absorption (lowering toxicity). Plain prilocaine (3% with felypressin) or mepivacaine can be used when adrenaline is best avoided.

9. List early and late signs of local anaesthetic systemic toxicity (LAST).

   Early: perioral tingling, metallic taste, tinnitus, dizziness, visual disturbance, confusion. Late: muscle twitching, seizures, then CNS and cardiovascular depression (bradycardia, hypotension, arrhythmia, arrest).

10. Define conscious sedation as used in UK dentistry.

    A technique using drug(s) to depress the CNS enabling treatment, during which verbal contact is maintained throughout. The margin of safety must be wide enough that loss of consciousness is unlikely; protective reflexes are retained.

11. Name the standard inhalation and the standard intravenous agents used for dental conscious sedation, and the IV monitoring requirement.

    Inhalation: nitrous oxide / oxygen ($\ce{N2O/O2}$) titrated; IV: midazolam (a benzodiazepine). IV sedation requires continuous pulse oximetry (and blood pressure) monitoring.

12. What is the reversal agent for benzodiazepine (midazolam) over-sedation, and its mechanism?

    Flumazenil, a competitive antagonist at the benzodiazepine site of the $\text{GABA}_A$ receptor. Initial dose $200$ micrograms IV, then $100$ micrograms at intervals; note its short half-life risks re-sedation.

13. Which ASA physical status grades are generally suitable for dental conscious sedation in a primary care setting?

    ASA I (healthy) and ASA II (mild systemic disease that is well controlled). ASA III and above usually require assessment and treatment in a specialist or hospital setting.

14. Give three indications for referral for dental treatment under general anaesthesia.

    Young children or patients with severe learning disability unable to cooperate; failed local anaesthesia/sedation; extensive or acutely infected surgery where LA is inadequate; severe dental anxiety unmanageable by sedation. GA carries the highest risk and is a last resort.

15. Why was general anaesthesia withdrawn from general dental practice in the UK, and where must it now be carried out?

    Because of mortality risk (Poswillo report); since 2002 dental GA must be provided only in a hospital setting with critical-care facilities and a dedicated anaesthetist.

16. A dental patient suddenly becomes pale, sweaty, with a slow pulse and faints. What is the most common medical emergency and its management?

    Vasovagal syncope (simple faint). Lay the patient flat and raise the legs to restore cerebral perfusion, loosen tight clothing, give oxygen, and monitor; recovery is usually rapid.

17. Differentiate vasovagal syncope from a hypoglycaemic episode and from anaphylaxis by the pulse.

    Syncope: bradycardia (slow pulse), pallor, rapid recovery when supine. Hypoglycaemia: often tachycardia, sweating, confusion, responds to glucose. Anaphylaxis: tachycardia with hypotension, airway/breathing signs, needs adrenaline.

18. How is an epileptic tonic-clonic seizure managed in the dental chair, and when is drug treatment indicated?

    Protect the patient from injury, do not restrain or put anything in the mouth, give oxygen, time the seizure. Give buccal midazolam $10$ mg (adult) if convulsions last $> 5$ minutes (status epilepticus) and call 999.

19. What drug, dose and route are given for a suspected myocardial infarction in the dental surgery?

    Sublingual GTN spray, aspirin $300$ mg chewed, high-flow oxygen if hypoxic, and call 999. Reassure and keep the patient comfortable; give analgesia and be ready to start CPR.

20. List the minimum emergency drugs that must be available in a UK dental practice (per Resuscitation Council UK).

    Adrenaline 1:1000 (IM), glucagon $1$ mg, oral glucose, glyceryl trinitrate (GTN) spray, salbutamol inhaler, aspirin $300$ mg, midazolam (buccal/oromucosal), and oxygen.

21. What emergency equipment must every UK dental practice hold, including the airway adjuncts and oxygen flow capability?

    Portable oxygen with capability to deliver $\geq 15$ L/min, oxygen masks with reservoir, pocket mask, self-inflating bag-valve-mask, oropharyngeal (Guedel) airways, portable suction, spacer device, and an automated external defibrillator (AED).

22. State the adult Basic Life Support sequence and compression parameters per current Resuscitation Council UK guidance.

    Check danger, response, airway, breathing; if not breathing normally call 999, get an AED, and start CPR at a ratio of $30$ compressions to $2$ rescue breaths. Compress the lower sternum at $5{-}6$ cm depth, rate $100{-}120$ per minute, allowing full recoil.

23. In adult cardiac arrest, which rhythms are 'shockable' versus 'non-shockable', and when is adrenaline given?

    Shockable: ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) — defibrillate. Non-shockable: pulseless electrical activity (PEA) and asystole. Give adrenaline $1$ mg IV immediately in non-shockable, or after the 3rd shock in shockable rhythms, then every 3-5 minutes.

24. Why must all medical emergencies and adverse events be documented contemporaneously, and what should a post-event review cover?

    For accurate medico-legal records, continuity of care and learning. Documentation should record the time, signs/symptoms, drugs and doses given (route/time), the patient's response, and the outcome. A post-event review (significant event audit) examines what happened, what went well, lessons learned, and updates to protocols, equipment checks and staff training.

What this deck covers

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