PLAB 1 Emergency medicine Questions: 10 Free Practice MCQs

Ten PLAB 1-style emergency medicine questions with the answer and the reasoning behind it. They come from the UK.med bank, which has 101 emergency medicine questions and many more across every topic.

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1. 1 / 10

   A 28-year-old male with a history of Ulcerative Colitis presents with a 5-day history of bloody diarrhoea. He reports passing 8 bloody stools per day. On examination, he is febrile (38.2°C), tachycardic (102 bpm), and has mild lower abdominal tenderness. His CRP is 65 mg/L.

   Which of the following is the most appropriate next step in management according to Truelove and Witts criteria?

   • A. Increase oral Mesalazine dose and review in outpatient clinic in 2 weeks
   • B. Start oral Prednisolone 40mg daily and discharge home with a stool chart
   • C. Admit for intravenous corticosteroids and monitor for toxic megacolon
   • D. Schedule an urgent outpatient colonoscopy to assess disease extent
   Show answer

   Answer: C. Admit for intravenous corticosteroids and monitor for toxic megacolon

   Why: NICE NG130 states that acute severe ulcerative colitis (defined by Truelove and Witts criteria as >= 6 bloody stools/day plus at least one sign of systemic toxicity: temp > 37.8°C, HR > 90 bpm, Hb < 105 g/L, or ESR/CRP elevated) requires immediate admission for IV corticosteroids (typically IV Hydrocortisone 100mg QDS).

   • A. Mesalazine is for mild-to-moderate colitis; a severe flare represents a medical emergency and cannot be treated with outpatient 5-ASA.
   • B. Oral steroids are suitable for moderate flares. Severe flares must be admitted to hospital for IV treatment due to the high risk of bowel perforation and toxic megacolon.
   • D. Full colonoscopy is contraindicated in acute severe colitis due to the high risk of perforation; a flexible sigmoidoscopy without bowel preparation is preferred if diagnosis is needed.

   Sources: NICE NG130

2. 2 / 10

   A 26-year-old man is brought to the emergency department by paramedics. He is unresponsive with a respiratory rate of 5 breaths/minute, pinpoint pupils, and cyanosis of his lips. Intravenous access is obtained.

   What is the most appropriate medication and administration strategy to reverse this presentation?

   • A. Intravenous Naloxone 4 mg bolus immediately to achieve full consciousness before transfer, repeated every 2 minutes until he is awake
   • B. Intravenous Flumazenil 500 mcg over 15 seconds, repeated until breathing improves
   • C. Intravenous Naloxone, titrated in small incremental doses to restore adequate respiration without inducing severe withdrawal
   • D. Endotracheal intubation and mechanical ventilation only
   Show answer

   Answer: C. Intravenous Naloxone, titrated in small incremental doses to restore adequate respiration without inducing severe withdrawal

   Why: Opioid toxicity is characterized by the triad of respiratory depression, pinpoint pupils, and coma. Naloxone is a competitive opioid antagonist. In patients who are not in cardiac arrest, Naloxone is administered in small, titrated IV doses (400 mcg is standard, but starting lower at 100-200 mcg is preferred in dependent users) to restore respiration while avoiding the precipitation of severe withdrawal syndromic agitation.

   • A. Giving a massive bolus of Naloxone causes acute withdrawal, severe pain, agitation, and potentially flash pulmonary edema, and is not recommended unless in cardiac arrest.
   • B. Flumazenil is the antidote for benzodiazepine overdose, not opioid overdose. Using it in chronic users can precipitate life-threatening seizures.
   • D. While airway support is vital, pharmacological reversal with Naloxone is highly effective and avoids the need for invasive ventilation in most cases.

   Sources: BNF Naloxone Monograph; Resuscitation Council UK guidelines

3. 3 / 10

   A 68-year-old male presents with persistent nosebleeding from his left nostril for 45 minutes. He has squeezed his nose and applied ice without success. On examination, his blood pressure is 150/90 mmHg. Rhinoscopy reveals an active bleeding point on the anterior nasal septum.

   What is the next most appropriate step in management?

   • A. Insert an anterior nasal pack (e.g., Merocel or Rapid Rhino) immediately
   • B. Prescribe oral Tranexamic acid and discharge home
   • C. Perform silver nitrate cautery of the bleeding point after applying topical anaesthetic
   • D. Apply ice packs to the nasal bridge and advise the patient to keep leaning back
   Show answer

   Answer: C. Perform silver nitrate cautery of the bleeding point after applying topical anaesthetic

   Why: The management of epistaxis starts with first aid (leaning forward, pinching the soft part of the nose for 10-15 minutes). If this fails and rhinoscopy identifies a visible anterior bleeding point (usually in Kiesselbach's plexus/Little's area), chemical cautery with silver nitrate is the first-line treatment. If cautery is unsuccessful or no bleeding point is identified, anterior nasal packing is indicated.

   • A. Nasal packing is uncomfortable and carries risk of mucosal damage; it is reserved for when cautery fails or when no bleeding point is visible.
   • B. Oral TXA is not first-line for active epistaxis, and discharging a patient with active bleeding is unsafe.
   • D. Patients with epistaxis should lean forward, not back, to avoid swallowing blood. First aid has already failed, so intervention is required.

   Sources: ENT UK Clinical Guidelines

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5. 4 / 10

   A 2-year-old presents with a barking cough and stridor at rest. He has mild recession.

   What is the single most important immediate pharmacological intervention?

   • A. Inhaled Salbutamol
   • B. Oral Dexamethasone
   • C. Nebulised Adrenaline
   • D. Antibiotics
   Show answer

   Answer: B. Oral Dexamethasone

   Why: Oral dexamethasone is the mainstay of treatment for croup (laryngotracheobronchitis) to reduce airway inflammation. Nebulised adrenaline is reserved for severe distress.

   • A. Not effective for upper airway obstruction like croup.
   • C. Used for severe/life-threatening croup, but steroids are given to all severity levels.
   • D. Croup is viral.

   Sources: NICE NG143; BTS Guidelines

6. 5 / 10

   A 45-year-old female with known Addison's disease is brought to the emergency department. She has been suffering from gastroenteritis with severe vomiting for 48 hours. On examination, she is drowsy and has a blood pressure of 80/40 mmHg.

   What is the most urgent pharmacological intervention required?

   • A. Oral Fludrocortisone 100 micrograms and oral rehydration salts
   • B. Intravenous Hydrocortisone 100mg and IV fluid resuscitation
   • C. High-dose intravenous Dexamethasone 8mg
   • D. Intramuscular Adrenaline 0.5mg
   Show answer

   Answer: B. Intravenous Hydrocortisone 100mg and IV fluid resuscitation

   Why: Adrenal crisis is treated with immediate bolus injection of 100mg IV Hydrocortisone, followed by continuous infusion or regular QDS boluses, alongside rapid infusion of 0.9% normal saline. Mineralocorticoid replacement (fludrocortisone) can be withheld during acute resuscitation as high-dose hydrocortisone has cross-reactivity at aldosterone receptors.

   • A. Oral treatment is contraindicated due to persistent vomiting. Fludrocortisone is not needed in the acute phase as high-dose hydrocortisone provides sufficient mineralocorticoid activity.
   • C. Hydrocortisone is preferred over dexamethasone in adrenal crisis due to its mineralocorticoid action. Dexamethasone is only used if an ACTH stimulation test is planned immediately.
   • D. Adrenaline is the treatment for anaphylaxis, not Addisonian crisis.

   Sources: Society for Endocrinology guidelines

7. 6 / 10

   An 8-year-old girl is brought to the emergency department with sudden onset generalized urticaria, facial swelling, and expiratory wheeze shortly after eating peanut butter. She is hypotensive and tachycardic.

   What is the most appropriate first-line treatment and dose of adrenaline according to Resuscitation Council UK guidelines?

   • A. Intravenous Adrenaline bolus 100 micrograms
   • B. Intramuscular Adrenaline 150 micrograms (0.15 mL of 1:1000)
   • C. Intramuscular Adrenaline 300 micrograms (0.3 mL of 1:1000)
   • D. Intravenous Chlorphenamine 5mg and Hydrocortisone 100mg
   Show answer

   Answer: C. Intramuscular Adrenaline 300 micrograms (0.3 mL of 1:1000)

   Why: Resuscitation Council UK anaphylaxis guidelines specify IM adrenaline (1:1000) doses by age: <6 months: 150 mcg (0.15 mL); 6 months to 6 years: 150 mcg (0.15 mL); 6 to 12 years: 300 mcg (0.3 mL); >12 years/Adults: 500 mcg (0.5 mL). Adrenaline is administered intramuscularly in the anterolateral thigh. IV antihistamines and steroids are secondary therapies.

   • A. Intravenous adrenaline is highly cardiotoxic and must only be administered by specialists in an intensive care setting; IM adrenaline is the standard first-line route.
   • B. 150 micrograms is the dose for children under 6 years of age. For children aged 6-12, the dose is 300 micrograms.
   • D. Antihistamines and steroids are second-line treatments. They must not delay the administration of life-saving intramuscular adrenaline.

   Sources: Resuscitation Council UK Anaphylaxis Guidelines

8. 7 / 10

   A 35-year-old develops rapid tongue swelling, wheeze and hypotension minutes after a food exposure. The reaction is progressing and skin signs are present.

   Which diagnosis best fits this presentation?

   • A. Anaphylaxis causing acute airway, breathing and circulatory compromise
   • B. A skin-limited allergic reaction without airway, breathing or circulation involvement
   • C. A panic attack causing subjective breathlessness but not tongue swelling or shock
   • D. A vasovagal faint without progressive airway swelling or wheeze
   Show answer

   Answer: A. Anaphylaxis causing acute airway, breathing and circulatory compromise

   Why: The rapid onset after food exposure with tongue swelling, wheeze and hypotension is anaphylaxis with airway, breathing and circulation involvement. A skin-only reaction or faint does not explain the objective airway and respiratory features. A rapid onset after a likely allergen with any acute airway, breathing or circulation compromise supports the clinical diagnosis; a skin rash is common but not required. Obtain a focused history and arrange follow-up after emergency stabilisation, but do not let either step delay treatment.

   • B. A skin-limited allergy does not account for the rapidly developing wheeze and hypotension.
   • C. Panic can cause distress and breathlessness, but it does not explain tongue oedema with hypotension after an allergen exposure.
   • D. A vasovagal episode may cause faintness, but it does not cause progressive tongue swelling and wheeze.

   Sources: Resuscitation Council UK Emergency treatment of anaphylaxis, May 2021, Sections 2.1 and 3, pages 14 to 22

9. 8 / 10

   A 4-year-old boy is assessed after passing painless dark-red stool twice in one morning. He has no diarrhoea, abdominal tenderness or fever. His haemoglobin is mildly reduced, and he is haemodynamically stable.

   What is the most likely mechanism of this child's condition?

   • A. Intussusception
   • B. Anal fissure
   • C. Ulceration of adjacent ileum caused by acid secretion from ectopic gastric mucosa in a Meckel diverticulum
   • D. Rectal polyp. A rectal polyp can cause recurrent painless bleeding, usually small-volume bright red blood rather than this acute dark red bleed.
   Show answer

   Answer: C. Ulceration of adjacent ileum caused by acid secretion from ectopic gastric mucosa in a Meckel diverticulum

   Why: A Meckel diverticulum containing ectopic gastric mucosa can secrete acid and ulcerate the adjacent ileum. This produces painless lower gastrointestinal bleeding, often dark red and sometimes substantial. The child requires urgent hospital evaluation and assessment of blood loss.

   • A. Intussusception causes bowel telescoping and usually presents with intermittent severe pain and vomiting.
   • B. A fissure causes a superficial painful tear and small-volume bright red bleeding, not a large painless dark red bleed.
   • D. A rectal polyp may bleed painlessly but is usually a small-volume, recurrent bright red bleed; it does not explain this classic dark red presentation as well.

   Sources: Acute Abdominal Pain Paediatric Pathway, Royal Cornwall Hospitals NHS Trust, 2023

10. 9 / 10

    A 2-year-old child accidentally inhales a small toy. He has a sudden onset of respiratory distress. On assessment, he is unable to vocalise or cry, has a silent cough, and is turning blue around the lips.

    What is the recommended first-line rescue sequence for this choking child according to Resuscitation Council UK guidelines?

    • A. Perform a blind finger sweep of the mouth to locate the toy
    • B. Perform 5 chest thrusts while holding the child head-down on the forearm
    • C. Deliver 5 back blows, followed by 5 abdominal thrusts (Heimlich manoeuvre)
    • D. Commence immediate chest compressions at a ratio of 15:2
    Show answer

    Answer: C. Deliver 5 back blows, followed by 5 abdominal thrusts (Heimlich manoeuvre)

    Why: The choking algorithm in children depends on age and consciousness. (1) Conscious child with effective cough: encourage coughing. (2) Conscious child with ineffective cough: (a) If infant < 1 year: 5 back blows, then 5 chest thrusts. (b) If child > 1 year: 5 back blows, then 5 abdominal thrusts. (3) Unresponsive child: open airway, give 5 rescue breaths, start CPR at a 15:2 ratio.

    • A. Blind finger sweeps are strictly contraindicated in choking children, as they can push the foreign object further down the pharynx, worsening the airway obstruction.
    • B. This is the choking protocol for an infant under 1 year of age. For children over 1 year, abdominal thrusts are used instead of chest thrusts.
    • D. Cardiopulmonary resuscitation (compressions and breaths) is only started if the choking child becomes unresponsive (unconscious). While the child is conscious, physical thrusts are used.

    Sources: Resuscitation Council UK Guidelines: Paediatric Choking (2021)

11. 10 / 10

    A 30-year-old man is brought to the emergency department unconscious following a high-speed motorcycle crash. He has a fluctuating level of consciousness, a dilated right pupil, and a suspected extradural haematoma. He requires emergency intubation, CT head, and transfer to neurosurgery. No family members or friends are present, and there is no record of his medical history or wishes.

    Under what legal authority should the medical team proceed with these emergency interventions?

    • A. Emergency police authorization, as the injury followed a road crash
    • B. Principle of 'best interests' under the Mental Capacity Act 2005
    • C. The doctrine of implied consent from attending hospital
    • D. Seek an emergency court order from the High Court
    Show answer

    Answer: B. Principle of 'best interests' under the Mental Capacity Act 2005

    Why: Under the Mental Capacity Act 2005, if a patient lacks capacity due to an acute event (such as unconsciousness from trauma), clinicians can provide necessary, life-saving treatment that is in the patient's best interests. Treatment should not be delayed to search for family or obtain consent unless there is clear evidence of a valid and applicable ADRT refusing such treatment.

    • A. The police do not have the legal authority to consent to or authorize medical treatment for citizens.
    • C. Implied consent is for minor non-invasive actions (e.g. rolling up a sleeve for a blood test), not major invasive interventions in unconscious patients.
    • D. Seeking a court order in a life-threatening emergency is inappropriate as the delay would result in the patient's death.

    Sources: Mental Capacity Act 2005; GMC Consent: Decision-making and consent

Exam-style questions written by MedHub for practice. They are not official exam questions.