# PLAB 1 Respiratory Questions: 10 Free Practice MCQs

> 10 free PLAB 1 respiratory questions with answers and explanations, from a bank of 90 respiratory questions. Try them now, no sign up.

Canonical: https://medhub.one/practice/plab-1/respiratory
Last updated: 2026-10-29

Ten PLAB 1-style respiratory questions with the answer and the reasoning behind it. They come from the UK.med bank, which has 90 respiratory questions and many more across every topic.

1. 1 / 10  
A 24-year-old female presents with a 3-month history of dry cough and wheeze, worse at night. Spirometry shows an FEV1/FVC ratio of 75%.  
What is the next most appropriate investigation to confirm the diagnosis of asthma according to NICE guidelines?  
Show answer

**Answer: B.** Fractional exhaled nitric oxide (FeNO)

**Why:** The current BTS, NICE and SIGN asthma guideline NG245 recommends measuring blood eosinophils or FeNO in adults with a history suggesting asthma. Asthma is diagnosed if eosinophils are above the laboratory reference range or FeNO is at least 50 ppb. If neither confirms asthma, measure bronchodilator reversibility with spirometry; a qualifying result is an FEV1 increase of at least 12% and 200 ml from baseline, or at least 10% of predicted normal FEV1\. Prior inhaled corticosteroid treatment can make FeNO and spirometry more likely to be normal.

  * **A.** A trial of treatment alone is no longer sufficiently diagnostic without objective testing.
  * **C.** CXR is useful to rule out other causes but does not confirm asthma.
  * **D.** NICE places twice-daily PEF monitoring for 2 weeks after eosinophils or FeNO and spirometric reversibility when earlier tests do not confirm asthma.  
Sources: BTS, NICE and SIGN NG245 recommendations 1.2.1 to 1.2.2
2. 2 / 10  
A 48-year-old woman presents with a 24-hour history of sudden onset shortness of breath and right-sided pleuritic chest pain. She has no significant past medical history. On examination, she is tachycardic at 112 bpm, but her chest is clear and there is no calf swelling. Her Wells score is calculated as 3 (representing 'PE unlikely').  
What is the most appropriate next step in management according to NICE guidelines?  
Show answer

**Answer: A.** Perform a D-dimer test; if positive, arrange an urgent CT pulmonary angiogram (CTPA)

**Why:** NICE guideline NG158 states that for patients with suspected PE, a two-level PE Wells score should be calculated. (1) PE likely (Wells score > 4): arrange immediate CTPA. (2) PE unlikely (Wells score <= 4): perform D-dimer test. If D-dimer is positive, arrange CTPA. While waiting for the scan, interim therapeutic anticoagulation (e.g. Apixaban) should be initiated if the scan cannot be performed within 4 hours.

  * **B.** A direct CTPA is indicated if the Wells score is > 4 ('PE likely'). For 'PE unlikely' (score <= 4), a D-dimer is checked first to avoid unnecessary radiation exposure.
  * **C.** While interim anticoagulation should be given if there is a delay in arranging imaging, diagnostic workup (D-dimer/CTPA) must be completed rather than prescribing a blind course of anticoagulation.
  * **D.** A normal chest examination is very common in PE and does not exclude it. Discharging this patient without a D-dimer is a major safety failure.  
Sources: NICE NG158
3. 3 / 10  
A 22-year-old woman is admitted to the emergency department with an acute asthma flare. She is speaking in broken sentences, has a respiratory rate of 28 breaths/min, and a heart rate of 115 bpm. Her peak expiratory flow (PEF) is 45% of her predicted baseline.  
What is the severity classification of her acute asthma attack and the most appropriate initial treatment?  
Show answer

**Answer: A.** Acute severe asthma; administer high-flow oxygen, nebulised Salbutamol 5mg, and oral Prednisolone 40mg

**Why:** According to the BTS/SIGN guidelines, acute severe asthma is defined by: PEF 33-50% of best/predicted, respiratory rate >= 25/min, heart rate >= 110/bpm, or inability to complete sentences in one breath. Management consists of supplemental oxygen to maintain saturations of 94-98%, nebulised beta-2 agonists (Salbutamol 5mg), and oral Prednisolone (40-50mg) or IV Hydrocortisone (100mg).

  * **B.** A peak flow of 45% combined with tachypnoea (RR 28) and tachycardia (HR 115) indicates acute severe asthma, not moderate, and requires nebulised treatment rather than a spacer.
  * **C.** Life-threatening asthma is defined by features such as silent chest, cyanosis, hypotension, exhaustion, confusion, or PEF < 33%. She does not have these features, so IV magnesium is not yet indicated.
  * **D.** Systemic corticosteroids (oral Prednisolone or IV Hydrocortisone) are mandatory for all acute severe asthma attacks, and should be administered immediately rather than delayed.  
Sources: BTS/SIGN British Guideline on the Management of Asthma
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5. 4 / 10  
A 74-year-old man presents with a 3-day history of productive cough, fever, and right-sided pleuritic chest pain. On examination, he is confused, has a respiratory rate of 32 breaths/min, and blood pressure is 88/54 mmHg. Bloods show urea of 8.5 mmol/L. His chest X-ray confirms right lower lobe consolidation.  
What is his CURB-65 score, and what is the recommended management setting?  
Show answer

**Answer: D.** CURB-65 score of 4; refer for urgent hospital admission

**Why:** NICE guideline NG138 recommends using the CURB-65 score to assess severity of community-acquired pneumonia. Points are awarded for: Confusion (AMTS <= 8/10), Urea > 7 mmol/L, Respiratory rate >= 30/min, Blood pressure (systolic < 90 or diastolic <= 60 mmHg), and Age >= 65\. Scores of 0-1 are low risk (home treatment), 2 is intermediate risk (consider hospital referral), and >= 3 is high risk (urgent hospital admission).

  * **A.** His score is 4, not 2\. Treating a patient with severe pneumonia (CURB-65 of 4) at home is dangerous and carries a very high mortality risk.
  * **B.** A score of 3 or 4 indicates high risk and mandates inpatient hospital care, not outpatient treatment.
  * **C.** His score is 4 (he does not have a 5th point). Intubation is a hospital-based critical care procedure, not performed in the GP clinic.  
Sources: NICE NG138
6. 5 / 10  
A 68-year-old male with severe COPD (known carbon dioxide retainer) is admitted with an acute exacerbation. He is tachypnoeic, has coarse expiratory wheeze, and is hypoxic. Arterial blood gas on room air shows: pH 7.36, pCO2 6.8 kPa, pO2 7.2 kPa, HCO3- 28 mmol/L.  
What is the most appropriate initial oxygen therapy and pharmacological management?  
Show answer

**Answer: C.** Prescribe oxygen via a 24% or 28% Venturi mask targeting saturations of 88-92%, nebulised Salbutamol, and oral Prednisolone 30mg

**Why:** NICE guideline NG115 outlines the management of COPD exacerbations. In patients with a history of hypercapnic respiratory failure, oxygen therapy should be titrated using Venturi masks to a target saturation of 88-92% to avoid worsening respiratory acidosis. Pharmacotherapy includes nebulised bronchodilators (Salbutamol and Ipratropium) and a 5-day course of oral Prednisolone 30mg.

  * **A.** High-flow oxygen targeting 94-98% in a known CO2 retainer can result in severe hypercapnia, respiratory acidosis, and coma.
  * **B.** CPAP is used for acute cardiogenic pulmonary oedema, not COPD. Non-invasive ventilation (NIV/BiPAP) is indicated if there is respiratory acidosis (pH < 7.35) despite medical therapy, but her pH is normal (7.36).
  * **D.** Nasal cannulae do not allow precise concentration delivery, making Venturi masks preferred. Antibiotics should only be given if there are signs of infection (purulent sputum), and the standard dose is 500mg, not 1g.  
Sources: NICE NG115
7. 6 / 10  
A 48-year-old female presents with sudden onset shortness of breath and pleuritic chest pain. She has no swelling or pain in her lower limbs. Her pulse rate is 98 bpm, BP is 120/80 mmHg, and oxygen saturation is 96% on room air. She has no previous history of VTE and no recent surgeries. A two-level PE Wells score is calculated as 1.5 (PE unlikely).  
What is the most appropriate next step in investigation according to NICE guidelines?  
Show answer

**Answer: A.** Perform a quantitative D-dimer test

**Why:** For patients with suspected PE who are stable, the initial assessment uses the Wells score. A Wells score of 4 or less indicates PE is unlikely. NICE NG158 advises a quantitative D-dimer test next. If the D-dimer is positive, a CTPA should be performed. If Wells score is >4, CTPA is the immediate first-line test.

  * **B.** CTPA is indicated initially if the Wells score is greater than 4 (PE likely), or if the D-dimer test is positive.
  * **C.** V/Q scans are typically reserved for patients where CTPA is contraindicated (e.g. severe renal impairment or contrast allergy) or inconclusive.
  * **D.** Anticoagulation should not be started without a positive CTPA, unless there is a delay in obtaining the CTPA after a positive D-dimer.  
Sources: NICE NG158
8. 7 / 10  
A 27-year-old with asthma attends a review and finds it difficult to describe how often symptoms wake them or limit activity. The clinician is considering a structured way to assess control.  
Which tool may be considered at an asthma review?  
Show answer

**Answer: B.** A validated symptom questionnaire such as the Asthma Control Test

**Why:** Consider a validated symptom questionnaire at an asthma review, such as the Asthma Control Questionnaire, Asthma Control Test or Childhood Asthma Control Test. It can support the discussion but should be considered alongside other control and risk information.

  * **A.** NICE NG245 does not recommend regular peak flow monitoring for all people to assess control.
  * **C.** A chest radiograph is not the validated symptom questionnaire described in the guideline.
  * **D.** Brand preference alone does not measure asthma control; use a validated symptom questionnaire if helpful.  
Sources: BTS NICE SIGN NG245 recommendation 1.5.2
9. 8 / 10  
A 68-year-old male is assessed in the GP surgery with a cough, purulent sputum, and breathlessness. On examination, he is confused (AMTS 6/10), his respiratory rate is 32 breaths/minute, and blood pressure is 115/65 mmHg. His urea is checked via point-of-care test and is 8.5 mmol/L.  
What is his CURB-65 score, and what is the recommended management setting?  
Show answer

**Answer: C.** CURB-65 score of 4; urgent hospital admission

**Why:** The CURB-65 score guides triage in CAP: Confusion (AMTS <= 8), Urea > 7 mmol/L, Respiratory rate >= 30/min, Blood pressure (systolic < 90 or diastolic <= 60 mmHg), and Age >= 65\. The patient score is 4 (C, U, R, 65). Under NICE NG138, a score of 3 or higher indicates severe pneumonia and requires urgent hospital admission.

  * **A.** His score is 4\. A score of 2 indicates moderate pneumonia and usually requires hospital assessment, while a score of 3 or 4 indicates severe disease.
  * **B.** His score is 4\. Outpatient treatment is inappropriate and unsafe for patients with a CURB-65 score >= 3.
  * **D.** His blood pressure is 115/65 mmHg. Since systolic is >= 90 and diastolic is >= 60, he does not get a point for blood pressure. Thus, his score is 4, not 5.  
Sources: NICE NG138; BTS guidelines
10. 9 / 10  
A 4-year-old improved during an inhaled corticosteroid trial, but symptoms returned by the 3 month review. The child has not yet had a further severe episode.  
What treatment approach is recommended?  
Show answer

**Answer: B.** Restart regular paediatric low-dose ICS with SABA as needed and titrate to a moderate dose if needed

**Why:** Restart regular inhaled corticosteroid at a paediatric low dose with SABA as needed because symptoms recurred by the 3-month review. NICE NG245 advises titrating to a paediatric moderate dose if needed and considering a further trial without treatment after review within 12 months. This is not an adult MART pathway.

  * **A.** Restarting at low dose is appropriate, but NICE allows titration to a paediatric moderate dose if needed when symptoms recur by the 3-month review.
  * **C.** An adult MART regimen is not recommended for this under-5 scenario; use age-appropriate regular paediatric ICS with SABA as needed.
  * **D.** Recurrence after stopping the successful trial supports restarting regular ICS rather than avoiding inhaled treatment.  
Sources: BTS NICE SIGN NG245 recommendation 1.9.4
11. 10 / 10  
A 70-year-old COPD patient presents with increased breathlessness and purulent sputum. Oxygen saturation is 88% on air (known retainer).  
What is the target oxygen saturation range?  
Show answer

**Answer: C.** 88-92%

**Why:** In COPD patients with a history of CO2 retention, the target saturation is 88-92% to avoid worsening hypercapnia caused by the Haldane effect and V/Q mismatch.

  * **A.** Risk of hypercapnic respiratory failure.
  * **B.** Dangerous.
  * **D.** Hypoxia must be treated.  
Sources: BTS Oxygen Guidelines

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