Free PLAB 1 Practice Questions

Sample Practice Questions

Try these 10 sample questions from the PLAB 1 practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A 32-year-old develops widespread urticaria, wheeze and a blood pressure of 75/40 mmHg immediately after an antibiotic injection. Help has been called and an intravenous cannula is already present. Which medicine should the doctor give first to treat the anaphylaxis?

   1. A.AdrenalineCorrect answer: A
   2. B.Chlorphenamine
   3. C.Hydrocortisone
   4. D.Salbutamol

   Explanation: "Intramuscular adrenaline is the first-line treatment for anaphylaxis (even if intravenous access is available)." Airway and circulatory compromise after an allergen require prompt intramuscular adrenaline. Intravenous access does not change the first-line treatment; the other medicines do not replace it.

   Reference: Resuscitation Council UK: Emergency treatment of anaphylaxis — Section 5.1, Adrenaline

2. 2A 20 kg child has confirmed hypoglycaemia and a reduced conscious level that prevents safe oral intake. Intravenous access is available. Using the RCUK bolus of 0.2 g/kg glucose, how much 10% glucose solution should be given?

   1. A.4 mL
   2. B.20 mL
   3. C.40 mLCorrect answer: C
   4. D.400 mL

   Explanation: "If oral intake is not possible, give an IV bolus of 0.2 g kg-1 glucose (2 mL kg-1 10% glucose) and re-check blood glucose after 5-10 min and repeat if necessary." Required glucose = 0.2 g/kg × 20 kg = 4 g. A 10% solution contains 10 g/100 mL = 0.1 g/mL, so volume = 4 g ÷ 0.1 g/mL = 40 mL. The 4 mL option mislabels grams as millilitres; 20 mL assumes a 20% solution; 400 mL misreads 10% as 0.01 g/mL. Recheck glucose after 5–10 minutes.

   Reference: Resuscitation Council UK: Paediatric life support (basic and advanced) — Management of the critically ill child: Disability

3. 3A patient has recurrent right upper abdominal pain after meals. Gallbladder stones are suspected, without signs of duct obstruction. Which investigation is usually used to confirm gallbladder stones initially?

   1. A.Abdominal ultrasonographyCorrect answer: A
   2. B.Magnetic resonance cholangiography
   3. C.Endoscopic retrograde cholangiography
   4. D.Abdominal computed tomography

   Explanation: "Gallstones can usually be confirmed using an ultrasound scan" Ultrasonography is the usual initial confirmation test for gallbladder stones. The duct-focused studies are considered when bile-duct involvement remains a concern; CT is not the usual first test specified here.

   Reference: NHS inform: Gallstones — Diagnosing gallstones: Ultrasound scan

4. 4A patient with type 1 diabetes has missed insulin and develops vomiting, deep breathing and breath that smells of pear drops. Blood glucose is 29 mmol/L and blood ketones are 6 mmol/L. Which acute metabolic complication is most likely?

   1. A.Lactic acidosis
   2. B.Starvation ketosis
   3. C.Diabetic ketoacidosisCorrect answer: C
   4. D.Hyperosmolar hyperglycaemic state

   Explanation: "DKA happens when there’s not enough insulin in your body." Insulin omission, marked ketonaemia, hyperglycaemia and the characteristic breathing and breath smell support DKA rather than isolated lactic acidosis, starvation ketosis or the usually less ketotic hyperosmolar state.

   Reference: NHS inform: Diabetic ketoacidosis — What causes diabetic ketoacidosis?

5. 5An untreated patient has repeated clinic blood pressure readings of 156/94 mmHg without symptoms of a hypertensive emergency. They can tolerate out-of-office monitoring. Which investigation is preferred to confirm hypertension?

   1. A.Ambulatory blood pressure monitoringCorrect answer: A
   2. B.Ambulatory electrocardiographic monitoring
   3. C.Transthoracic echocardiographic examination
   4. D.Exercise electrocardiographic stress testing

   Explanation: "If clinic blood pressure is between 140/90 mmHg and 180/120 mmHg, offer ambulatory blood pressure monitoring (ABPM) to confirm the diagnosis of hypertension." The clinic reading falls within this interval. The other investigations assess rhythm, cardiac structure or inducible ischaemia rather than confirming sustained hypertension.

   Reference: NHS Somerset cardiovascular prescribing guidance — Diagnosing Hypertension

6. 6A patient spends hours repeating handwashing rituals to neutralise intrusive contamination fears. They recognise that the rituals are excessive but feel driven to perform them. Which diagnosis best explains this presentation?

   1. A.Generalised anxiety disorder
   2. B.Obsessive compulsive disorderCorrect answer: B
   3. C.Schizotypal personality disorder
   4. D.Somatic symptom disorder

   Explanation: "Compulsions start as a way of trying to reduce or prevent anxiety caused by the obsessive thought, although in reality, this behaviour is either excessive or not realistically connected." Intrusive unwanted fears followed by anxiety-relieving rituals with insight are characteristic of OCD rather than the other disorders.

   Reference: NHS OCD symptoms — Compulsive behaviour

7. 7A patient develops intermittent ptosis and diplopia that worsen late in the day and improve after rest. Pupils are normal. Which diagnosis is most likely?

   1. A.Myasthenia gravisCorrect answer: A
   2. B.Oculomotor nerve palsy
   3. C.Horner syndrome
   4. D.Thyroid eye disease

   Explanation: "It tends to be worse when you're tired and gets better after resting." Fatigable ocular muscle weakness with recovery after rest characterises myasthenia. Fixed cranial nerve palsy, sympathetic dysfunction and thyroid orbitopathy do not explain this fatigability pattern.

   Reference: NHS myasthenia gravis symptoms — Symptoms: introductory description of fluctuating muscle weakness

8. 8A palliative-care patient starts regular morphine and has no diarrhoea or bowel obstruction. Which accompanying medicine class addresses the common persistent bowel adverse effect?

   1. A.Antiemetic medicines
   2. B.Antisecretory medicines
   3. C.Antispasmodic medicines
   4. D.Laxative medicinesCorrect answer: D

   Explanation: "Constipation is very common. You should be prescribed a laxative to take regularly, while you are on opioid medicines." A laxative prevents or treats opioid-associated constipation. Antiemetics address nausea, antisecretory drugs reduce secretions and antispasmodics address spasm.

   Reference: Leeds Teaching Hospitals opioids in palliative care — 4. What are the most common side-effects of opioids?

9. 9A woman has fever, dysuria, vomiting and unilateral loin tenderness with a positive urine culture. Which diagnosis best accounts for the systemic illness and loin pain?

   1. A.Acute pyelonephritisCorrect answer: A
   2. B.Uncomplicated cystitis
   3. C.Urethral syndrome
   4. D.Acute interstitial nephritis

   Explanation: "a high temperature feeling or being sick pain in your lower back or side" Fever and loin symptoms with urinary infection suggest upper-tract infection, or pyelonephritis. The other conditions do not explain this systemic upper-tract presentation.

   Reference: NHS kidney infection — Symptoms of a kidney infection

10. 10A patient develops a mechanical small-bowel obstruction years after abdominal surgery. There is no hernia or tumour on assessment. Which cause best explains this obstruction?

    1. A.Abdominal adhesionsCorrect answer: A
    2. B.Mesenteric arterial embolism
    3. C.Sigmoid diverticulitis
    4. D.Acute pancreatitis

    Explanation: "Abdominal adhesions are the most common cause of obstruction of the small intestine." Adhesions explain postoperative mechanical obstruction. The other abdominal disorders do not best explain this mechanical postoperative presentation.

    Reference: NIDDK abdominal adhesions — Intestinal obstruction