PLAB 1 (UKMLA AKT) respiratory questions

NICE NG80 recommends spirometry as the first objective test in adults with suspected asthma, looking for an obstructive pattern (FEV1/FVC ratio <70%) with significant bronchodilator reversibility (improvement in FEV1 of 12% or more and 200 mL or more). FeNO testing is used as a second-line test if spirometry is normal or shows obstruction without significant reversibility, particularly to support a diagnosis when there is diagnostic uncertainty. Peak flow diaries are useful for monitoring variability over time but are not the first-line diagnostic test. Allergy testing and chest X-ray may be used to investigate triggers or exclude alternative diagnoses but are not the initial diagnostic step.

• A. Chest X-ray is used to exclude other pathology, not to diagnose asthma.
• B. Allergy testing identifies triggers but does not establish the diagnosis of asthma itself.
• C. Peak flow diaries assess diurnal variability over time and support diagnosis but are not the first test performed.
• E. FeNO is used as a second-line test after spirometry, not as the initial investigation.

A silent chest on auscultation, as described here by absent breath sounds despite visible respiratory effort, is a hallmark feature of life-threatening asthma according to British Thoracic Society/SIGN criteria, reflecting such severe airflow limitation that air movement is insufficient to generate audible wheeze. Other life-threatening features include SpO2 <92%, PEF <33% of predicted or best, exhaustion, cyanosis, hypotension, arrhythmia, and a silent chest. Tachypnoea, tachycardia and inability to complete sentences are features of acute severe asthma but do not by themselves meet life-threatening criteria. SpO2 of 90% is below the life-threatening threshold of 92%, but silent chest is the most specific and classic life-threatening sign described.

• A. Inability to complete sentences indicates severe, not life-threatening, asthma.
• B. Tachycardia is a feature of severe asthma but is not itself diagnostic of a life-threatening attack.
• C. While SpO2 <92% is a life-threatening criterion, the silent chest is the most classic and specific sign described in this vignette.
• D. Raised respiratory rate is a feature of severe, not specifically life-threatening, asthma.

In acute severe asthma that fails to respond adequately to initial nebulised bronchodilators and corticosteroids, the British Thoracic Society/SIGN and Resuscitation Council UK-aligned guidance recommends a single dose of intravenous magnesium sulfate 1.2-2 g given over 20 minutes as the next step, as it acts as a bronchodilator via smooth muscle relaxation and has been shown to reduce hospital admission in this setting. Repeating nebulisers alone without escalation is insufficient given the poor response. IV aminophylline is reserved for cases not responding to initial therapy including magnesium sulfate, under senior guidance due to its narrow therapeutic index. IV hydrocortisone would duplicate the action of the oral steroid already given. Intubation is reserved for life-threatening or near-fatal asthma with respiratory failure, which is not yet demonstrated here.

• A. Intubation is reserved for life-threatening asthma with respiratory failure, not yet indicated here.
• C. Oral corticosteroid has already been given; IV hydrocortisone would not add significant benefit at this stage.
• D. Aminophylline is considered only after magnesium sulfate has been tried, under senior advice.
• E. Simply repeating nebulisers without escalating therapy is inadequate given the lack of response.

Montelukast, a leukotriene receptor antagonist, is associated with neuropsychiatric adverse effects including sleep disturbance, nightmares, irritability, anxiety, depression, and rarely suicidal ideation, and the MHRA has issued safety advice recommending that patients and carers be counselled on these risks before starting treatment. Any new neuropsychiatric symptoms following initiation warrant prompt review and consideration of stopping the drug. Inhaled corticosteroids such as beclometasone and long-acting beta-agonists such as salmeterol are not typically associated with these neuropsychiatric effects. Theophylline toxicity causes seizures, arrhythmias and gastrointestinal symptoms rather than mood disturbance, and salbutamol typically causes tremor and tachycardia.

• B. Salbutamol commonly causes tremor, tachycardia and hypokalaemia, not neuropsychiatric disturbance.
• C. Beclometasone, an inhaled corticosteroid, is not associated with neuropsychiatric adverse effects at standard doses.
• D. Theophylline toxicity presents with seizures, arrhythmias and gastrointestinal upset rather than mood change.
• E. Salmeterol is associated with tremor and palpitations, not neuropsychiatric symptoms.

Beta-2 adrenergic agonists such as salbutamol stimulate the Na+/K+-ATPase pump, particularly in skeletal muscle, driving potassium from the extracellular to the intracellular space and causing a transient hypokalaemia without total body potassium depletion. This same beta-2 mediated mechanism also explains the tachycardia seen with beta-agonist overuse, through stimulation of cardiac beta receptors. Renal excretion is not the primary mechanism in acute beta-agonist-induced hypokalaemia, nor is gastrointestinal loss or dilution, as this patient has not vomited or had excessive fluid intake. Salbutamol does not act on aldosterone secretion.

• B. Salbutamol does not act via inhibition of aldosterone secretion.
• C. There is no history of excessive fluid intake suggesting dilutional hypokalaemia.
• D. Renal excretion is not the primary mechanism of acute hypokalaemia from beta-agonist overuse.
• E. There is no history of vomiting or gastrointestinal loss in this vignette.

A rising PaCO2 above the normal range in a patient with acute severe asthma, especially accompanied by drowsiness, reduced respiratory effort and acidosis, indicates evolving respiratory failure and near-fatal asthma, mandating urgent involvement of anaesthetics or intensive care for consideration of intubation and mechanical ventilation. A normal or rising PaCO2 in an acute asthma attack is an ominous sign, as hyperventilation should otherwise cause a low PaCO2; its normalisation or rise signals exhaustion and impending respiratory arrest. Escalating nebulised or intravenous bronchodilator therapy or repeating magnesium sulfate does not address the immediate need for airway and ventilatory support in a patient who is tiring and losing respiratory drive.

• B. IV salbutamol infusion is not standard first-line and does not address the need for ventilatory support in this deteriorating patient.
• C. Aminophylline does not address the urgent need for airway protection and ventilatory support.
• D. Repeating magnesium sulfate will not reverse imminent respiratory failure in a drowsy, exhausted patient.
• E. Escalating nebulised therapy does not address the immediate risk of respiratory arrest from exhaustion.

The calculated FEV1/FVC ratio here is 1.4/2.8 = 0.5, which is below 0.7 and confirms airflow obstruction. In COPD, this obstruction shows little or no improvement after bronchodilator, distinguishing it from asthma where significant reversibility (an increase in FEV1 of 12% or more and 200 mL or more) is typical. A chronic history of smoking with progressive, non-variable symptoms supports the diagnosis of COPD rather than asthma. NICE guidance confirms COPD diagnosis using post-bronchodilator spirometry showing a persistently low FEV1/FVC ratio.

• B. A ratio above 0.7 with normal volumes would indicate normal spirometry, not the obstructive pattern calculated here.
• C. Full reversibility after bronchodilator is characteristic of asthma, not the fixed obstruction seen in COPD.
• D. A mixed pattern would require evidence of reduced lung volumes in addition to obstruction, which is not described.
• E. A ratio above 0.7 would suggest a restrictive rather than obstructive process, which does not fit this result.

NICE NG115 recommends that patients with COPD who remain symptomatic on a short-acting bronchodilator alone, and who do not have asthmatic features or factors suggesting steroid responsiveness, should step up to a combined LABA/LAMA inhaler. Asthmatic features include a history of atopy, higher blood eosinophil counts, substantial FEV1 variation, or diurnal symptom variation; none are present here. LABA/ICS combinations are reserved for patients with these steroid-responsive features. Triple therapy is reserved for those who remain symptomatic on dual LABA/LAMA therapy.

• A. Inhaled corticosteroid monotherapy is not used in COPD management outside combination inhalers.
• B. This combination is appropriate only when asthmatic or steroid-responsive features are present, which this patient lacks.
• D. A short-acting muscarinic antagonist would not be stepped up to in place of a long-acting combination inhaler and duplicates her existing need for maintenance therapy.
• E. Triple therapy is the next step only if symptoms persist on LABA/LAMA therapy, not the initial add-on step.

This patient has an infective exacerbation of COPD with purulent sputum, warranting a course of antibiotics in addition to standard exacerbation management. Standard treatment includes controlled oxygen therapy titrated to a saturation target of 88-92% to avoid hypercapnic narcosis, nebulised bronchodilators (salbutamol and ipratropium), and a short course of oral corticosteroids such as prednisolone. His blood gas shows a compensated respiratory acidosis without severe acidaemia, so non-invasive ventilation is not yet indicated. NICE and BTS guidance recommend antibiotics, typically amoxicillin, doxycycline or clarithromycin, when sputum becomes purulent during an exacerbation.

• A. Non-invasive ventilation is reserved for persisting respiratory acidosis despite optimal medical therapy, which has not yet been trialled here.
• C. A saturation target of 94-98% is too high for a patient at risk of hypercapnic respiratory failure, and antibiotics should be given given the purulent sputum.
• D. Purulent sputum indicates likely bacterial infection, so antibiotics should be included in his management.
• E. High-flow oxygen risks worsening hypercapnia in COPD, and intravenous steroids are not required when oral administration is tolerated.

This patient has persisting type 2 respiratory failure with respiratory acidosis (pH less than 7.35, raised PaCO2) despite optimal medical therapy for an adequate period, which is the standard indication for non-invasive ventilation in COPD exacerbations. She is conscious, cooperative and able to protect her airway, making her an appropriate candidate for BiPAP rather than invasive ventilation. Resuscitation Council UK and BTS guidance support starting NIV promptly once this threshold is met, as early use reduces the need for intubation and improves outcomes. Increasing the oxygen concentration further risks worsening hypercapnia without addressing the underlying ventilatory failure.

• A. Raising oxygen concentration further could worsen CO2 retention without correcting the acidosis.
• B. Doxapram is rarely used now and is not the guideline-recommended next step when NIV is appropriate and available.
• D. Aminophylline is not first-line and would not address the ventilatory failure as effectively as NIV.
• E. Invasive ventilation is reserved for patients failing NIV, who cannot tolerate it, or who cannot protect their airway, none of which apply here.

Smoking cessation is the single most effective intervention to slow the accelerated decline in FEV1 seen in COPD, as continued smoking perpetuates airway inflammation and lung tissue destruction. Studies have shown that stopping smoking reduces the rate of lung function decline towards that of a non-smoker, whereas continued smoking leads to a steeper, progressive loss. While pulmonary rehabilitation, vaccination and appropriate inhaled therapy improve symptoms, exercise capacity and reduce exacerbation frequency, none alter the underlying trajectory of lung function decline as smoking cessation does. NICE NG115 emphasises offering smoking cessation advice and support at every opportunity.

• A. Inhaled corticosteroids reduce exacerbation frequency in selected patients but do not match smoking cessation in slowing disease progression.
• B. Long-term oxygen therapy improves survival in selected hypoxaemic patients but does not slow lung function decline.
• D. Influenza vaccination reduces exacerbation risk from infection but does not address the underlying mechanism of decline.
• E. Pulmonary rehabilitation improves exercise tolerance and quality of life but does not alter the rate of FEV1 decline.

Early-onset emphysema in a young non-smoker, particularly with a lower lobe predominant pattern and a family history of liver disease, is characteristic of alpha-1 antitrypsin deficiency. This autosomal co-dominant condition results in reduced hepatic production of alpha-1 antitrypsin, a protease inhibitor that normally protects lung tissue from neutrophil elastase, leading to unchecked tissue destruction and panacinar emphysema. The deficient protein can also accumulate in hepatocytes, causing liver cirrhosis, which explains the family history described. Diagnosis is confirmed with a low serum alpha-1 antitrypsin level and genotyping, and management includes smoking avoidance and, in severe cases, augmentation therapy.

• B. Hypersensitivity pneumonitis causes a restrictive pattern with ground-glass changes, not an obstructive emphysematous pattern.
• C. Idiopathic pulmonary fibrosis causes a restrictive pattern with basal reticular changes, not obstructive emphysema.
• D. Allergic bronchopulmonary aspergillosis typically presents with asthma-like symptoms, eosinophilia and central bronchiectasis rather than panacinar emphysema.
• E. Cystic fibrosis usually presents in childhood with recurrent infections and bronchiectasis, not isolated adult-onset emphysema.

For low-severity community-acquired pneumonia (CURB-65 score 0-1) without penicillin allergy, NICE and BNF guidance recommends a 5-day course of oral amoxicillin as first-line empirical therapy, as Streptococcus pneumoniae remains the most common causative organism. Amoxicillin provides adequate cover for typical bacterial pathogens in low-severity disease without the broader spectrum needed for atypical or more severe infection. Macrolides or doxycycline are reserved for penicillin allergy or atypical pathogen suspicion. Co-amoxiclav and fluoroquinolones are not first-line for low-severity CAP due to unnecessarily broad spectrum and resistance concerns.

• A. Co-amoxiclav has a broader spectrum than needed for low-severity CAP and is reserved for more severe disease.
• B. Ciprofloxacin has poor pneumococcal cover and is not recommended for standard CAP treatment.
• D. Doxycycline is an alternative for penicillin-allergic patients, not first-line choice.
• E. Clarithromycin is reserved for penicillin allergy or suspected atypical pathogens, not first-line in uncomplicated low-severity CAP.

In high-severity community-acquired pneumonia (CURB-65 score 3-5), NICE guidance recommends dual therapy with a broad-spectrum beta-lactam, such as intravenous co-amoxiclav, combined with a macrolide such as clarithromycin, to cover both typical bacterial pathogens and atypical organisms including Legionella and Mycoplasma. Monotherapy with a narrow-spectrum agent such as amoxicillin is insufficient for severe disease. This combination reduces mortality in severe CAP by ensuring broad coverage while awaiting culture results.

• A. Doxycycline alone is inadequate monotherapy for severe pneumonia requiring broad bacterial and atypical cover.
• B. Amoxicillin alone has too narrow a spectrum and inadequate severity coverage for CURB-65 score 5.
• C. Benzylpenicillin alone does not cover atypical organisms and is insufficient for severe CAP.
• D. Vancomycin plus meropenem is reserved for suspected hospital-acquired or resistant organism infection, not standard severe CAP.

Mycoplasma pneumoniae classically causes a gradual-onset atypical pneumonia in young adults, often with extrapulmonary manifestations including erythema multiforme, a hypersensitivity reaction presenting as target lesions with dusky centres, typically affecting the palms, soles and extensor surfaces. Other extrapulmonary features include haemolytic anaemia and arthralgia. Chest X-ray often shows diffuse patchy infiltrates that look worse than the clinical picture suggests. Streptococcus pneumoniae and Haemophilus influenzae cause typical lobar pneumonia without this skin association, and Legionella more typically presents with hyponatraemia and derangement of liver function.

• A. Legionella pneumophila is associated with hyponatraemia and gastrointestinal symptoms, not erythema multiforme.
• B. Haemophilus influenzae typically causes pneumonia in patients with underlying lung disease and is not linked to erythema multiforme.
• C. Staphylococcus aureus pneumonia is associated with cavitation and often follows influenza, not erythema multiforme.
• D. Streptococcus pneumoniae causes typical lobar pneumonia and is not associated with erythema multiforme.

Legionella pneumophila causes pneumonia following exposure to contaminated water sources such as air conditioning systems, hot tubs and spa pools, often in a travel context. Characteristic features include hyponatraemia (due to inappropriate ADH secretion), deranged liver function tests, and gastrointestinal symptoms such as diarrhoea alongside respiratory symptoms. Urinary antigen testing is the diagnostic test of choice. The combination of recent foreign travel with hotel pool exposure, hyponatraemia and deranged LFTs strongly points to this diagnosis over other atypical organisms.

• A. Coxiella burnetii (Q fever) is linked to exposure to farm animals, not spa or pool water.
• B. Mycoplasma pneumoniae is associated with young adults, erythema multiforme and cold agglutinin haemolytic anaemia, not travel-related water exposure and hyponatraemia.
• C. Chlamydophila psittaci is linked to exposure to infected birds, not water systems.
• D. Streptococcus pneumoniae causes typical lobar pneumonia without the systemic features described here.

Aspiration pneumonia occurs when oropharyngeal or gastric contents are inhaled into the lungs, commonly in patients with impaired swallowing, reduced consciousness or neurological disease affecting airway protection, as in this patient with dysphagia following stroke and a reduced conscious level. The right lower lobe is frequently affected due to the more vertical and wider right main bronchus. The causative organisms are typically a mixture of aerobic and anaerobic bacteria normally found in the oral cavity, reflecting the polymicrobial nature of aspirated oropharyngeal secretions. This differs from typical or atypical community-acquired pneumonia pathogens.

• B. Mycoplasma pneumoniae is typically seen in younger patients without aspiration risk factors.
• C. Chlamydophila psittaci is associated with bird exposure, not aspiration.
• D. Pneumocystis jirovecii causes pneumonia in immunocompromised patients, not typically aspiration-related.
• E. Legionella pneumophila is linked to water exposure, not aspiration risk factors.

Lobar pneumonia classically produces homogeneous consolidation confined to the anatomical boundaries of a single lobe, with air bronchograms visible as lucent, branching air-filled bronchi within the opacified lung, reflecting alveolar filling with inflammatory exudate while the airways remain patent. Pulmonary oedema typically shows bilateral perihilar (bat-wing) shadowing with upper lobe venous diversion and cardiomegaly, reflecting fluid overload rather than infection. A spiculated mass suggests malignancy, and diffuse reticulonodular shadowing suggests an interstitial process rather than lobar consolidation.

• A. Diffuse reticulonodular shadowing suggests an interstitial lung process rather than lobar consolidation.
• B. Bilateral pleural effusions with cardiomegaly suggest heart failure rather than lobar pneumonia.
• C. Bilateral perihilar haziness with upper lobe venous diversion is characteristic of pulmonary oedema, not lobar pneumonia.
• D. A spiculated mass with irregular margins is characteristic of malignancy, not infective consolidation.

The low pH (<7.2), low glucose and turbid appearance with organisms on Gram stain indicate an empyema, a recognised complication of pneumonia. Empyema and complicated parapneumonic effusions require prompt drainage with a chest drain in addition to continued antibiotics, as fluid alone will not resolve without mechanical removal of infected material. Delaying drainage risks loculation, fibrosis and the need for surgical intervention. Antibiotic adjustment alone does not address the need for source control.

• A. This presentation with empyema features requires admission and drainage, not discharge.
• B. Antibiotic escalation does not achieve source control of infected pleural fluid.
• C. Cytology is relevant for suspected malignancy, not for managing confirmed empyema.
• E. CT may help delineate loculation but is not the immediate next step before drainage is arranged.

Patients with chronic conditions such as diabetes mellitus are classified as clinically at-risk groups and should receive the pneumococcal polysaccharide vaccine (PPV23) as a one-off dose, along with the annual inactivated influenza vaccine. These vaccines reduce the incidence and severity of pneumococcal pneumonia and influenza-related complications in at-risk adults. UK guidance (Green Book/NHS) recommends vaccination regardless of age once a risk factor such as diabetes is present. Live attenuated influenza vaccine is used in children, not adults with comorbidities, who receive the inactivated vaccine.

• A. Diabetes mellitus is a risk factor that mandates vaccination irrespective of age.
• B. Hib vaccine is part of the childhood immunisation schedule and not indicated here.
• C. Adults, especially those with comorbidities, receive the inactivated influenza vaccine, not the live attenuated nasal spray used in children.
• D. BCG protects against tuberculosis and is not relevant to this indication.

In patients with suspected pulmonary embolism, the two-level Wells score should be calculated first to stratify pre-test probability and guide the choice and urgency of investigation. A score of 4 or less indicates PE is 'unlikely' and prompts a D-dimer test, while a score above 4 indicates PE is 'likely' and warrants an immediate CT pulmonary angiogram. This structured approach, recommended by NICE, avoids unnecessary imaging in low-risk patients while ensuring timely definitive imaging in higher-risk patients. Jumping straight to imaging or treatment bypasses this validated risk-stratification step.

• A. Arterial blood gases may show hypoxaemia but cannot confirm or exclude PE and are not part of the diagnostic algorithm.
• B. Echocardiography is used in suspected massive PE with haemodynamic instability, not as a first-line investigation in a stable patient.
• C. Empirical anticoagulation without any risk assessment or imaging is not appropriate in a stable patient.
• D. V/Q scanning is reserved for specific situations such as renal impairment or contrast allergy, not as the first step before risk stratification.

When the Wells score indicates PE is 'likely' (score above 4), the patient should proceed directly to CT pulmonary angiography (CTPA), which is the investigation of choice for diagnosing PE as it directly visualises thrombus in the pulmonary arteries. D-dimer testing is unnecessary and inappropriate in high pre-test probability patients because a negative result does not reliably exclude PE in this group. CTPA also has the advantage of identifying alternative diagnoses. V/Q scanning is reserved for patients in whom CTPA is contraindicated, such as significant renal impairment or contrast allergy.

• A. D-dimer should not be used when PE is 'likely' as it does not change management in high pre-test probability patients.
• B. A chest X-ray is often normal in PE and cannot establish the diagnosis.
• D. V/Q scan is a second-line alternative, used when CTPA is contraindicated, not the first choice here.
• E. Leg Doppler may support a diagnosis of DVT but does not confirm or exclude PE itself.

D-dimer is a sensitive but non-specific marker that can be raised in many conditions including infection, pregnancy, malignancy, trauma and recent surgery, so an elevated result does not confirm PE. In a patient where PE is 'unlikely' by Wells score, a raised D-dimer means PE cannot be excluded on this basis alone and should prompt CTPA. Conversely, a normal D-dimer in a low-probability patient is used to safely rule out PE without further imaging. This selective use of D-dimer prevents unnecessary CTPA in truly low-risk patients while avoiding missed diagnoses in those with a borderline or raised result.

• A. An elevated, not normal, D-dimer does not exclude PE and must be followed by imaging.
• B. D-dimer is not diagnostic for PE and cannot be used alone to confirm the diagnosis or start treatment.
• C. This statement is reversed: a normal D-dimer, not an elevated one, is reassuring in a low-probability patient.
• E. Repeating the same non-specific test does not add diagnostic value; imaging is required instead.

In haemodynamically unstable ('massive') PE, where there is hypotension or shock, systemic thrombolysis with a thrombolytic agent such as alteplase is the first-line emergency treatment to rapidly dissolve the clot and restore pulmonary blood flow, as recommended by Resuscitation Council UK and NICE guidance. Anticoagulation alone with heparin or a DOAC does not act quickly enough to reverse the acute right heart strain causing shock. Imaging should not delay life-saving treatment in a patient who is too unstable to wait; thrombolysis can be given based on strong clinical suspicion with bedside echocardiographic evidence of right ventricular strain.

• B. Definitive imaging should not delay thrombolysis in a patient too unstable to survive the delay.
• C. Oral anticoagulants have a delayed onset of action and are inappropriate in the acute unstable setting.
• D. IVC filters are used to prevent further emboli in specific situations, not as first-line treatment of an acute massive PE.
• E. Heparin alone does not rapidly lyse the clot and is insufficient in a shocked patient needing immediate reperfusion.

This young, tall, thin man with no underlying lung disease presenting with sudden pleuritic chest pain, reduced breath sounds, hyperresonance and a visible rim of pleural air on chest X-ray without mediastinal shift has a classic primary spontaneous pneumothorax (PSP). PSP typically occurs due to rupture of subpleural blebs in patients without clinically apparent lung disease, and tall thin young men are a recognised risk group. The absence of tracheal deviation or haemodynamic compromise excludes tension pneumothorax. BTS guidance measures pneumothorax size at the level of the hilum on a standard erect chest X-ray.

• B. Secondary pneumothorax occurs in patients with pre-existing lung disease such as COPD, which this patient does not have.
• C. Pulmonary embolism would not produce hyperresonance and a visible pleural air rim on X-ray.
• D. Pneumomediastinum presents with chest pain and subcutaneous crepitus, not a pleural air rim with reduced breath sounds.
• E. Tension pneumothorax causes tracheal deviation and haemodynamic compromise, both absent here.

This patient has a tension pneumothorax, indicated by hypotension, tachycardia, tracheal deviation away from the affected side, absent breath sounds, hyperresonance and raised jugular venous pressure. This is a clinical diagnosis requiring immediate needle decompression, classically with a large-bore cannula inserted into the second intercostal space in the mid-clavicular line, without waiting for imaging. Delaying treatment to obtain a chest X-ray or CT risks cardiovascular collapse and death, as tension pneumothorax causes mediastinal shift that impairs venous return. A formal chest drain follows decompression once the tension is relieved.

• A. A formal chest drain is the definitive treatment but should follow, not replace, immediate needle decompression.
• B. Fluids alone will not relieve the underlying mechanical obstruction to venous return and do not address the cause.
• C. Tension pneumothorax is a clinical diagnosis and treatment must not be delayed for imaging.
• E. CT imaging takes far too long and is inappropriate in a peri-arrest patient with a clinical diagnosis.

This patient has a secondary spontaneous pneumothorax due to underlying COPD. BTS guidance uses a lower threshold for intervention in secondary pneumothorax because of reduced respiratory reserve: any patient over 50 years old with a secondary pneumothorax that has a rim greater than 2 cm and/or the patient is breathless should have a chest drain inserted rather than aspiration or observation. This patient is over 50, breathless with hypoxia, and has a rim over 2 cm, so chest drain insertion is indicated rather than the more conservative approach used in primary pneumothorax.

• A. Outpatient discharge without intervention is inappropriate given his hypoxia, breathlessness and rim size in the context of secondary pneumothorax.
• C. Aspiration alone is reserved for smaller, minimally symptomatic secondary pneumothoraces in younger patients; this patient meets criteria for drain insertion.
• D. Observation alone is unsafe given his significant hypoxia and symptomatic secondary pneumothorax exceeding 2 cm.
• E. There are no features of tension pneumothorax (no tracheal deviation or haemodynamic compromise), so emergency decompression is not indicated.

NICE guideline NG12 recommends an urgent chest X-ray within 2 weeks for people aged 40 and over who have two or more unexplained symptoms suggestive of lung cancer, such as persistent cough and weight loss, in someone who has ever smoked; a single such symptom in a current or ex-smoker aged over 40 also warrants the same urgency. This patient's age, smoking history, persistent cough and weight loss together meet this threshold, making urgent chest X-ray the appropriate initial investigation before specialist referral.

• A. Sputum cytology is not the recommended first-line investigation in primary care for suspected lung cancer under NG12.
• B. Referral without first obtaining a chest X-ray bypasses the recommended initial imaging step in primary care.
• C. Reassurance and delayed review is inappropriate given the red flag combination of symptoms and smoking history, which requires urgent imaging.
• D. CT chest is a secondary care investigation typically following an abnormal or suspicious chest X-ray, not the initial primary care step.

This patient has hyponatraemia with low serum osmolality but inappropriately concentrated urine (urine osmolality greater than serum osmolality) and elevated urine sodium despite clinical euvolaemia, consistent with syndrome of inappropriate antidiuretic hormone secretion (SIADH). Small cell lung cancer is the classic paraneoplastic cause, as tumour cells can ectopically secrete antidiuretic hormone, leading to water retention and dilutional hyponatraemia. The central hilar mass and heavy smoking history support small cell lung cancer as the underlying malignancy.

• A. Bone metastases causing hypercalcaemia do not produce this hyponatraemic, concentrated-urine picture.
• B. Dermatomyositis is a paraneoplastic skin and muscle disorder unrelated to this biochemical presentation.
• D. Hypercalcaemia via PTHrP, typically from squamous cell carcinoma, would cause elevated rather than low calcium and does not explain this sodium and osmolality pattern.
• E. Ectopic ACTH secretion causes Cushing's syndrome with features like hypertension and hyperglycaemia, not the biochemical picture of hyponatraemia with concentrated urine seen here.

Lambert-Eaton myasthenic syndrome (LEMS) is a paraneoplastic condition most commonly associated with small cell lung cancer, caused by autoantibodies directed against presynaptic voltage-gated calcium channels at the neuromuscular junction, impairing acetylcholine release. Clinically it causes proximal muscle weakness that characteristically improves with repeated use (post-tetanic potentiation), reduced reflexes that become more brisk after exercise, and autonomic symptoms such as dry mouth, distinguishing it from myasthenia gravis, in which weakness typically worsens with activity. The central hilar mass and heavy smoking history support an underlying small cell lung cancer.

• A. Guillain-Barre syndrome presents with ascending weakness and areflexia following infection, not an exercise-related improvement pattern linked to malignancy.
• B. The eponym and option name are altered; the genuine paraneoplastic antibody target in this syndrome is voltage-gated calcium channels, not potassium channels.
• C. Myasthenia gravis involves antibodies against acetylcholine receptors and causes weakness that worsens, not improves, with sustained activity.
• D. Polymyositis causes symmetrical proximal weakness without the autonomic features or improvement with exercise seen in LEMS.

Squamous cell lung cancer is classically associated with humoral hypercalcaemia of malignancy, caused by tumour secretion of parathyroid hormone-related peptide (PTHrP), which binds PTH receptors in bone and kidney to increase bone resorption and renal calcium reabsorption. This explains the suppressed native PTH level despite high calcium. Phosphate is typically low because PTHrP, like PTH, increases renal phosphate excretion. This mechanism differs from bony metastases, which cause hypercalcaemia through local osteolysis rather than a systemic hormone.

• A. A low PTH makes a primary parathyroid adenoma unlikely, as these cause high PTH.
• B. This mechanism is typically seen in lymphoma, not squamous cell lung cancer.
• C. This mechanism causes localised bone pain and lysis rather than the systemic pattern seen here, and does not suppress native PTH as markedly.
• D. There is no primary renal tubular pathology described, and this would not explain the hilar mass.

A Pancoast tumour arises at the lung apex and can invade local structures including the cervical sympathetic chain, producing Horner's syndrome: miosis, partial ptosis and anhidrosis on the affected side. This is a direct mechanical mechanism from local tumour extension rather than a systemic paraneoplastic process. The combination of apical lung mass, arm pain from brachial plexus involvement, and Horner's syndrome is the classic triad of Pancoast syndrome. Recognising this triad in a smoker should prompt urgent imaging and specialist referral.

• A. Phrenic nerve compression causes diaphragmatic paralysis and breathlessness, not Horner's syndrome.
• B. Recurrent laryngeal nerve compression causes hoarseness, not the described facial findings.
• C. The findings are explained by local structural compression rather than an autoimmune process.
• D. Lower trunk brachial plexus compression explains the arm pain but not the pupillary and facial findings.

Superior vena cava obstruction is an oncological emergency usually caused by extrinsic compression or invasion of the SVC by a right-sided lung tumour or mediastinal lymphadenopathy. It presents with facial and neck swelling, distended neck and chest wall veins, facial plethora, and symptoms worsened by lying flat due to increased venous congestion. Management includes sitting the patient upright, urgent CT imaging, and consideration of vascular stenting, with definitive oncological treatment guided by tissue diagnosis. This diagnosis should always be considered in a patient with known or suspected lung cancer presenting with facial swelling.

• A. Pericardial tamponade typically presents with hypotension, raised jugular venous pressure and muffled heart sounds, not facial plethora with distended chest wall veins.
• B. Acute heart failure typically causes bilateral leg oedema and pulmonary crackles rather than isolated facial and neck swelling with chest wall vein distension.
• D. Anaphylaxis presents acutely with urticaria, wheeze and hypotension following an allergen exposure, not a gradual presentation in a patient with a known lung mass.
• E. Massive pulmonary embolism presents with sudden breathlessness, chest pain and haemodynamic compromise, not facial and neck swelling.

Idiopathic pulmonary fibrosis typically presents in older patients with progressive exertional breathlessness, dry cough, finger clubbing and bilateral fine end-inspiratory crackles at the lung bases. The spirometry pattern is restrictive, with a reduced FVC, a preserved or elevated FEV1/FVC ratio (above 0.7), reflecting proportionally reduced lung volumes rather than airflow obstruction. This contrasts with obstructive diseases such as COPD, where the FEV1/FVC ratio is reduced. The combination of clinical findings and a restrictive spirometry pattern in an older patient without an identifiable cause points to idiopathic pulmonary fibrosis.

• B. COPD causes an obstructive pattern with a reduced FEV1/FVC ratio below 0.7, not the preserved ratio seen here.
• C. Bronchiectasis typically presents with chronic productive cough and coarse crackles, and spirometry usually shows an obstructive pattern.
• D. Hypersensitivity pneumonitis usually has an identifiable antigen exposure history, which is absent here.
• E. Heart failure can cause crackles and breathlessness but would not typically cause clubbing or this restrictive spirometry pattern without other cardiac signs.

The usual interstitial pneumonia (UIP) pattern on high-resolution CT, characteristic of idiopathic pulmonary fibrosis, shows a subpleural and basal predominant reticular pattern with honeycombing, defined as clustered cystic airspaces typically in a subpleural distribution. This pattern, together with traction bronchiectasis and absence of features suggesting an alternative diagnosis, allows a confident diagnosis of IPF without the need for lung biopsy in many cases. Honeycombing reflects end-stage fibrotic lung destruction and is a key diagnostic criterion. Recognising this pattern distinguishes IPF from other interstitial lung diseases with different CT distributions.

• B. Diffuse ground-glass opacity with air trapping is more typical of hypersensitivity pneumonitis.
• C. Bilateral hilar lymphadenopathy with perilymphatic nodules is characteristic of sarcoidosis.
• D. Centrilobular nodules with tree-in-bud pattern suggest infectious or inflammatory small airways disease, such as endobronchial spread of infection.
• E. Upper lobe fibrosis with calcified nodes is more typical of chronic silicosis or previous tuberculosis.

Malignant mesothelioma is strongly associated with occupational asbestos exposure, particularly in trades such as shipbuilding, pipe lagging and insulation work, with a latency period of decades between exposure and presentation. It typically presents with chest pain, breathlessness and a pleural effusion, and CT often shows nodular pleural thickening, which should raise suspicion for malignancy rather than benign plaques. Diagnosis requires pleural fluid cytology or pleural biopsy, as imaging findings alone cannot confirm malignancy. A detailed occupational history is essential in any patient with pleural disease, as asbestos-related conditions have long latency and major medico-legal and compensation implications.

• B. Pneumonia would typically present acutely with fever and systemic infective symptoms, and the chronic occupational history and nodular pleural thickening point away from an infective cause.
• C. Simple pleural plaques are usually asymptomatic and do not cause a large effusion or nodular thickening.
• D. Idiopathic pulmonary fibrosis causes bibasal fibrosis and crackles, not a unilateral pleural effusion with nodular thickening.
• E. Coal worker's pneumoconiosis is linked to coal dust exposure, not asbestos, and presents with parenchymal nodularity rather than nodular pleural thickening and effusion.

Extrinsic allergic alveolitis (hypersensitivity pneumonitis), also known as farmer's lung, is caused by a type III (and later type IV) hypersensitivity reaction to inhaled organic antigens such as thermophilic actinomycetes in mouldy hay. Symptoms characteristically occur hours after antigen exposure and resolve with avoidance, distinguishing it from asthma, which causes immediate wheeze. Fine bilateral crackles and reticulonodular shadowing reflect the inflammatory and fibrotic changes in the interstitium and small airways. Management is antigen avoidance, and corticosteroids are used in acute or persistent cases.

• B. Occupational asthma causes wheeze and reversible airflow obstruction rather than crackles and reticulonodular shadowing.
• C. Chronic bronchitis is defined by a productive cough for 3 months in 2 consecutive years, usually in smokers, not episodic exposure-related illness.
• D. ABPA occurs in patients with asthma or cystic fibrosis and is driven by Aspergillus colonisation, not transient occupational antigen exposure.
• E. Pulmonary oedema would show signs of fluid overload such as raised JVP and bibasal crackles with cardiac history, not exposure-related episodic illness.

The combination of bilateral hilar lymphadenopathy, erythema nodosum, arthralgia and mild hypercalcaemia in a young woman is classic for sarcoidosis, a multisystem granulomatous disease of unknown cause. Hypercalcaemia results from unregulated conversion of vitamin D to its active form by activated macrophages within granulomas. This presentation, sometimes called Löfgren syndrome, has a good prognosis and often resolves spontaneously without treatment. Diagnosis is supported by elevated serum ACE and tissue biopsy showing non-caseating granulomas if confirmation is needed.

• A. Bronchial carcinoma typically presents in older smokers with unilateral hilar enlargement, haemoptysis and weight loss, not symmetrical bilateral nodes with erythema nodosum.
• B. Lymphoma can cause lymphadenopathy but does not typically cause erythema nodosum and would more often show asymmetric or mediastinal mass-like nodes.
• C. TB can cause erythema nodosum but typically presents with unilateral hilar lymphadenopathy, productive cough, night sweats and a relevant exposure history.
• D. Silicosis follows occupational dust exposure and causes upper zone fibrosis and egg-shell calcification, not acute erythema nodosum.

In a patient with symptoms and chest X-ray findings suggestive of active pulmonary TB who can produce sputum, sputum smear microscopy for acid-fast bacilli and mycobacterial culture are the initial investigations of choice. Microscopy gives a rapid result to guide infection control and empirical treatment, while culture confirms the diagnosis and allows drug susceptibility testing, although it takes weeks. The tuberculin skin test and interferon-gamma release assay detect immune sensitisation to mycobacterial antigens and are used to diagnose latent TB infection, not active disease. Bronchoscopy is reserved for patients unable to expectorate sputum spontaneously or after induction.

• A. The Mantoux test detects prior sensitisation to mycobacterial antigens and is used for latent TB screening, not diagnosing active disease.
• C. Bronchoscopy is invasive and reserved for patients who cannot produce sputum spontaneously or by induction.
• D. Interferon-gamma release assays diagnose latent TB infection and cannot distinguish latent from active disease.
• E. CT chest can characterise the lesion further but does not provide microbiological confirmation of active TB.

Standard first-line treatment for fully sensitive active pulmonary TB, per NICE guidance, is a 6-month regimen: an initial 2-month intensive phase with four drugs (rifampicin, isoniazid, pyrazinamide and ethambutol, RIPE) followed by a 4-month continuation phase with two drugs (rifampicin and isoniazid). Pyrazinamide and ethambutol are given only during the intensive phase to rapidly reduce bacterial load and prevent resistance, while rifampicin and isoniazid continue throughout to sterilise remaining organisms. This regimen balances cure rates against drug toxicity and duration of treatment.

• A. Four drugs for only 2 months without a continuation phase would undertreat the infection and risk relapse.
• B. This combination and duration do not match the standard RIPE regimen structure.
• C. All four drugs for the full 6 months is unnecessarily prolonged exposure to pyrazinamide and ethambutol, which are only needed for the initial 2 months.
• E. Two drugs alone for the full duration is insufficient and risks resistance; four drugs are needed initially.

Rifampicin causes harmless orange-red discolouration of body fluids including urine, tears, sweat and saliva, which should be explained to patients to prevent unnecessary alarm or discontinuation. Rifampicin is also a potent inducer of hepatic cytochrome P450 enzymes, which accelerates metabolism of the combined oral contraceptive pill and reduces its efficacy, so additional or alternative contraception should be advised. This enzyme induction also affects other drugs such as warfarin and phenytoin, requiring dose adjustment or monitoring. Patients should be warned about both effects before starting treatment.

• B. Pyrazinamide is associated with hepatotoxicity and hyperuricaemia, not fluid discolouration.
• C. Ethambutol is associated with optic neuritis and visual disturbance, not fluid discolouration.
• D. Pyridoxine is given to prevent isoniazid-induced neuropathy and does not cause fluid discolouration.
• E. Isoniazid is associated with peripheral neuropathy and hepatotoxicity, not orange discolouration.

Isoniazid can cause peripheral neuropathy by interfering with pyridoxine (vitamin B6) metabolism, increasing its excretion and reducing its availability for neurotransmitter and myelin synthesis. Patients at higher risk, including those with diabetes, chronic kidney disease, alcohol excess, HIV or pregnancy, should be co-prescribed pyridoxine prophylactically to reduce this risk. Visual monitoring is relevant to ethambutol, which can cause optic neuritis, not isoniazid. Reducing the isoniazid dose would compromise treatment efficacy rather than addressing the underlying mechanism.

• A. Reducing the dose compromises treatment efficacy and is not the correct preventive strategy; pyridoxine supplementation is used instead.
• C. Visual acuity and colour vision monitoring is used for ethambutol-induced optic neuritis, not isoniazid neuropathy.
• D. Folic acid is not relevant to isoniazid-induced neuropathy; it is used in conditions like methotrexate therapy or pregnancy.
• E. Thiamine deficiency causes neuropathy in conditions like alcohol excess but is not the mechanism of isoniazid-induced neuropathy.

Ethambutol causes dose-dependent optic neuritis, presenting with reduced visual acuity and impaired red-green colour discrimination due to toxic effects on the optic nerve. Visual acuity and colour vision should be checked before starting treatment and monitored during therapy, especially in patients with renal impairment where the drug accumulates. The drug should be stopped immediately if visual symptoms develop, as changes may be irreversible if treatment continues. Isoniazid causes peripheral neuropathy, pyrazinamide causes hepatotoxicity and hyperuricaemia, rifampicin causes hepatotoxicity and orange discolouration of secretions, and streptomycin causes ototoxicity and nephrotoxicity.

• A. Pyrazinamide is associated with hepatotoxicity and hyperuricaemia, not optic neuritis.
• B. Rifampicin causes hepatotoxicity and orange discolouration of body fluids, not visual loss.
• C. Streptomycin causes ototoxicity and nephrotoxicity rather than optic nerve damage.
• E. Isoniazid typically causes peripheral neuropathy, not visual disturbance.

Interferon-gamma release assay (IGRA) measures T-cell release of interferon-gamma in response to M. tuberculosis-specific antigens, which are absent from the BCG vaccine strain, giving it higher specificity than the Mantoux test in previously vaccinated individuals. UK guidance recommends IGRA, often following an initial Mantoux test, for latent TB screening in groups such as healthcare workers and new entrants from high-incidence countries. Sputum smear, culture and CT imaging are used to investigate active, symptomatic disease rather than latent infection. A normal chest X-ray and absence of symptoms make active disease unlikely here, supporting a latent infection screening pathway.

• A. Sputum culture is used for active disease confirmation, not for asymptomatic latent infection screening.
• B. Sputum smear is used to diagnose active pulmonary TB in symptomatic patients, not latent infection.
• C. The Mantoux test can give false positives in BCG-vaccinated individuals, making IGRA preferable in this group.
• D. CT chest is used to investigate suspected active disease or complications, not for latent TB screening.

Acute epiglottitis presents with rapid-onset stridor, drooling, fever and a preference for sitting forward (tripod positioning), classically in unvaccinated children due to Haemophilus influenzae type b. Any examination or manipulation of the throat, including use of a tongue depressor or throat swab, risks precipitating complete airway obstruction through laryngospasm and must be avoided. The priority is to keep the child calm and summon senior anaesthetic and ENT input for controlled airway assessment, ideally in theatre, rather than attempting investigations first. Imaging should not delay escalation to airway specialists in a child with clinical features strongly suggestive of epiglottitis.

• A. Examining the oropharynx can trigger complete airway obstruction and must be avoided if epiglottitis is suspected.
• B. Imaging should not delay urgent senior airway specialist involvement in suspected epiglottitis.
• C. Salbutamol treats bronchospasm, not the upper airway obstruction caused by epiglottitis.
• E. Taking a throat swab requires throat manipulation, which risks precipitating airway obstruction.

Croup (laryngotracheobronchitis) is a viral illness, usually caused by parainfluenza virus, presenting with a barking cough, hoarseness and inspiratory stridor following a prodrome of coryza. A single dose of oral dexamethasone (0.15 mg/kg) is recommended for all children with croup regardless of severity, as it reduces symptom duration and the need for further medical attention. Nebulised adrenaline is reserved for severe croup with marked respiratory distress or impending respiratory failure, which this child does not have given her stable oxygen saturation and ability to drink. Antibiotics are not indicated as croup is viral, and nebulised budesonide is an alternative only when oral dexamethasone cannot be tolerated, not a first-line substitute.

• A. Croup is viral, so antibiotics such as benzylpenicillin are not indicated.
• B. Nebulised adrenaline is reserved for severe croup with significant respiratory distress, not mild-to-moderate presentations.
• C. Oral dexamethasone is first-line; budesonide is an alternative only when the oral route is not tolerated.
• D. Amoxicillin is not indicated as croup is a viral illness.

Anaphylaxis with respiratory and cardiovascular compromise requires immediate intramuscular adrenaline, which is the first-line treatment to reverse bronchospasm, laryngeal oedema and hypotension through alpha and beta-adrenergic effects. Resuscitation Council UK guidance recommends an adult dose of 500 micrograms (0.5 mL of 1:1000 adrenaline) given intramuscularly into the anterolateral aspect of the middle third of the thigh, which has better absorption than the deltoid. Intravenous adrenaline is reserved for specialist use in refractory anaphylaxis with close monitoring due to the risk of dangerous arrhythmias. Antihistamines and corticosteroids may be given as adjuncts but are not first-line and do not replace adrenaline in the acute management of anaphylaxis.

• B. Hydrocortisone is an adjunct treatment and should not be given before or instead of adrenaline.
• C. Intravenous adrenaline carries a high risk of arrhythmia and is reserved for refractory cases managed by specialists, not first-line treatment.
• D. Chlorphenamine is an adjunct treatment and does not replace adrenaline as first-line therapy.
• E. The anterolateral thigh, not the deltoid, is the recommended site due to better absorption of intramuscular adrenaline.

This blood gas shows hypoxaemia (PaO2 7.2 kPa, below the normal range of 10.5-13.5 kPa) with hypercapnia (PaCO2 7.8 kPa, above the normal range of 4.6-6.0 kPa), which defines type 2 respiratory failure. The low pH of 7.30 confirms acidosis, and because the primary abnormality is a raised PaCO2, this is a respiratory acidosis. The raised bicarbonate of 30 mmol/L reflects partial renal compensation that has not yet normalised the pH, consistent with an acute-on-chronic picture in a patient with COPD. Type 1 respiratory failure refers to hypoxaemia with a normal or low PaCO2, which is not the case here.

• A. The pH is low, indicating acidosis, not alkalosis.
• B. Type 1 respiratory failure requires a normal or low PaCO2, but this patient has marked hypercapnia.
• D. Type 1 respiratory failure requires a normal or low PaCO2, and the acid-base disturbance here is respiratory, not metabolic.
• E. The raised bicarbonate here is compensatory for a respiratory acidosis, not a primary metabolic alkalosis, and the pH remains low.

Obstructive sleep apnoea is suspected clinically from a history of loud snoring, witnessed apnoeas and excessive daytime sleepiness, often screened using a validated tool such as the Epworth Sleepiness Scale, where a score above 10 suggests significant sleepiness. Polysomnography is the gold-standard investigation, recording airflow, respiratory effort, oxygen saturation, heart rate and sleep staging to calculate the apnoea-hypopnoea index and confirm the diagnosis and severity. Pulse oximetry alone can support a diagnosis in some settings but lacks the detail needed to differentiate apnoea types or assess sleep architecture, making it less definitive. Spirometry assesses airflow obstruction in conditions such as COPD and asthma, and is not used to diagnose sleep-disordered breathing.

• A. Chest X-ray has no role in diagnosing obstructive sleep apnoea.
• C. Arterial blood gas does not assess sleep-related breathing events and is not diagnostic of OSA.
• D. Oximetry alone can screen for desaturation but does not provide the detailed sleep and respiratory data needed to confirm the diagnosis.
• E. Spirometry assesses lung function and airway obstruction, not sleep-related breathing disturbances.

The clinical history of chronic productive cough with recurrent infections and HRCT findings of dilated, thick-walled bronchi without normal tapering confirm a diagnosis of bronchiectasis. Long-term management centres on regular airway clearance techniques, such as chest physiotherapy and postural drainage, to reduce mucus stasis, prevent infection and preserve lung function, alongside prompt treatment of exacerbations with antibiotics guided by sputum culture. Long-term corticosteroids are not routinely used in bronchiectasis and carry significant adverse effects without proven benefit in most patients. Surgery is reserved for localised disease causing severe symptoms refractory to medical therapy, and long-term oxygen or inhaled muscarinic antagonists are not standard first-line measures for uncomplicated bronchiectasis.

• A. Inhaled muscarinic antagonists are used in COPD and are not standard first-line therapy for bronchiectasis.
• C. Surgery is reserved for localised disease refractory to medical management, not first-line therapy.
• D. Long-term home oxygen is only indicated if there is chronic respiratory failure with hypoxaemia, not routinely for bronchiectasis.
• E. Long-term oral corticosteroids are not routinely indicated in bronchiectasis and carry significant adverse effects.