A 24-year-old woman with asthma presents to the Emergency Department with a severe exacerbation. She is speaking in words only, has a respiratory rate of 32/min, heart rate 128/min, and peak expiratory flow 35% of her best. She has already received nebulized salbutamol 5mg and ipratropium 500 micrograms, oral prednisolone 40mg, and oxygen therapy. Thirty minutes later there is no improvement. According to BTS/SIGN guidelines, what is the most appropriate additional treatment?
Q72
A 38-year-old woman with occupational asthma presents for review. She works as a baker and experiences wheeze and breathlessness that improve on weekends and holidays. Peak flow monitoring shows variability exceeding 20% with lowest readings during working days. She is currently using beclometasone 400 micrograms twice daily and salbutamol as required. What is the single most important next step in her management?
Q73
A 58-year-old man with newly diagnosed COPD attends a respiratory clinic for spirometry. His post-bronchodilator results show FEV1 1.8L (60% predicted), FVC 3.2L, and FEV1/FVC ratio 0.56. He is an active smoker with a 35 pack-year history and reports breathlessness on moderate exertion (MRC dyspnoea scale 2). He has had no exacerbations in the past year. What is the most appropriate initial pharmacological management according to NICE guidelines?
Q74
A 32-year-old woman presents to the Emergency Department with an acute asthma exacerbation. She receives nebulised salbutamol 5mg and ipratropium 500 micrograms with oxygen, oral prednisolone 40mg, and controlled oxygen therapy. Initial peak flow was 30% of her best. After 1 hour of treatment, repeat observations show: heart rate 128 bpm, respiratory rate 30 breaths/min, oxygen saturation 91% on 40% oxygen, peak flow 32% of best. She appears exhausted and is speaking in words only. Arterial blood gas shows: pH 7.28, PaCO2 6.8 kPa, PaO2 8.1 kPa, HCO3- 24 mmol/L on 40% oxygen. What is the most critical next step in management?
Q75
A 52-year-old woman with newly diagnosed asthma has been using a salbutamol inhaler as required and started on beclometasone 200 micrograms twice daily 8 weeks ago. She returns for review reporting she still experiences wheeze and breathlessness three times per week and is woken by symptoms once weekly. She uses her salbutamol inhaler 4-5 times per week. Her inhaler technique is checked and is good. What is the most appropriate next step in her asthma management?
Q76
A 67-year-old man is diagnosed with acute pulmonary embolism confirmed on CT pulmonary angiogram. He has no contraindications to anticoagulation. His observations show: heart rate 118 bpm, blood pressure 98/65 mmHg, respiratory rate 26 breaths/min, oxygen saturation 91% on 4L oxygen. CTPA shows extensive bilateral pulmonary emboli with evidence of right ventricular dilatation (RV:LV ratio >1). Troponin is elevated at 150 ng/L. What risk category does this represent and what is the most appropriate immediate management?
Q77
A 35-year-old woman who is 28 weeks pregnant presents with sudden onset breathlessness and right-sided pleuritic chest pain. She is haemodynamically stable with oxygen saturations of 96% on room air. Pulmonary embolism is suspected. Chest X-ray is normal. What is the most appropriate imaging investigation to diagnose PE in this patient?
Q78
A 42-year-old woman presents with left-sided pleuritic chest pain and mild breathlessness for 24 hours. She takes no regular medications apart from the combined oral contraceptive pill. Her Wells score for PE is calculated as 1.5 (PE unlikely). Observations are normal except for heart rate 92 bpm. D-dimer is reported as 650 ng/ml (elevated, normal <500 ng/ml). What is the most appropriate next step in management?
Q79
A 58-year-old woman presents to the Emergency Department with sudden onset right-sided pleuritic chest pain and breathlessness that started 2 hours ago. She underwent a right total hip replacement 10 days ago. Observations: heart rate 110 bpm, blood pressure 128/82 mmHg, respiratory rate 22 breaths/min, oxygen saturation 94% on room air, temperature 36.8°C. Chest examination is unremarkable. ECG shows sinus tachycardia. What is the most appropriate initial investigation?
Q80
A 68-year-old man is admitted with severe community-acquired pneumonia (CURB-65 score 4). He is started on intravenous co-amoxiclav and clarithromycin. Blood cultures are taken. Despite 48 hours of treatment, he remains febrile with persistent hypoxia requiring 6L oxygen. Chest X-ray shows progression of consolidation with a small pleural effusion. Urinary Legionella antigen is negative. Sputum microscopy shows Gram-positive diplococci and culture is awaited. What is the most appropriate modification to antibiotic therapy?
Respiratory Medicine UK Medical PG Practice Questions and MCQs
Question 71: A 24-year-old woman with asthma presents to the Emergency Department with a severe exacerbation. She is speaking in words only, has a respiratory rate of 32/min, heart rate 128/min, and peak expiratory flow 35% of her best. She has already received nebulized salbutamol 5mg and ipratropium 500 micrograms, oral prednisolone 40mg, and oxygen therapy. Thirty minutes later there is no improvement. According to BTS/SIGN guidelines, what is the most appropriate additional treatment?
A. IV hydrocortisone 100mg
B. IV magnesium sulphate 2g over 20 minutes (Correct Answer)
C. IV aminophylline 5mg/kg loading dose
D. IM adrenaline 500 micrograms
E. Non-invasive ventilation
Explanation: ***IV magnesium sulphate 2g over 20 minutes***
- This is the recommended next step for patients with **acute severe or life-threatening asthma** who do not show a prompt response to initial therapy, as per BTS/SIGN guidelines.
- It acts as a **smooth muscle relaxant** and has been shown to improve lung function and reduce hospital admissions in patients with severe airflow obstruction.
*IV hydrocortisone 100mg*
- The patient has already received **oral prednisolone**, and oral corticosteroids are as effective as intravenous ones if the patient can swallow.
- Systemic corticosteroids have a **delayed onset of action** (several hours), so adding another steroid immediately after 30 minutes of no improvement is not the most urgent next step for rapid bronchodilation.
*IV aminophylline 5mg/kg loading dose*
- Aminophylline is typically considered a **third-line agent** for acute severe asthma and should only be used after senior consultation, usually if the patient fails to respond to magnesium sulphate.
- It has a **narrow therapeutic index** and is associated with significant side effects, including arrhythmias, seizures, and gastrointestinal upset.
*IM adrenaline 500 micrograms*
- This is the **first-line treatment for anaphylaxis**, which presents with distinct features like stridor, angioedema, or widespread urticaria, not just isolated asthma symptoms.
- While adrenaline can be used in **near-fatal asthma** in specific scenarios, it is not part of the standard management algorithm for refractory acute severe asthma without features of anaphylaxis.
*Non-invasive ventilation*
- **Non-invasive ventilation (NIV)** is generally **not recommended** in acute severe asthma due to high airway resistance and the risk of barotrauma or delaying definitive intubation.
- If the patient's condition deteriorates to **respiratory failure** or near-fatal asthma, **endotracheal intubation** and mechanical ventilation are the appropriate interventions.
Question 72: A 38-year-old woman with occupational asthma presents for review. She works as a baker and experiences wheeze and breathlessness that improve on weekends and holidays. Peak flow monitoring shows variability exceeding 20% with lowest readings during working days. She is currently using beclometasone 400 micrograms twice daily and salbutamol as required. What is the single most important next step in her management?
A. Increase inhaled corticosteroid dose to 800 micrograms twice daily
B. Add a long-acting beta-2 agonist to her current treatment
C. Refer for specialist occupational health assessment and consider workplace modification or relocation (Correct Answer)
D. Start oral prednisolone 40mg daily for 5 days
E. Add a leukotriene receptor antagonist to her current regimen
Explanation: ***Refer for specialist occupational health assessment and consider workplace modification or relocation***
- The definitive management for **occupational asthma**, such as baker's asthma caused by **flour dust**, is to identify and eliminate or significantly reduce exposure to the causative agent. Continued exposure can lead to **irreversible lung damage**.
- A specialist **occupational health assessment** is crucial to confirm the diagnosis, evaluate workplace conditions, and facilitate necessary **workplace modifications** or, if unavoidable, relocation to protect the worker's health.
*Increase inhaled corticosteroid dose to 800 micrograms twice daily*
- Increasing the dose of **inhaled corticosteroids** only treats the symptoms and does not address the **underlying cause** of her asthma, which is ongoing exposure to an occupational sensitizer.
- Without controlling the exposure, the patient is likely to continue experiencing symptoms and may face **disease progression** despite higher medication doses.
*Add a long-acting beta-2 agonist to her current treatment*
- While **LABAs** are a component of step-up therapy for general asthma, they primarily provide symptomatic relief and do not prevent the **immunological reaction** or chronic inflammation induced by workplace allergens.
- This approach allows continued exposure to the trigger, which can lead to **irreversible airway obstruction** over time, despite symptomatic improvement.
*Start oral prednisolone 40mg daily for 5 days*
- **Oral prednisolone** is typically reserved for acute asthma exacerbations, not for the ongoing management of occupational asthma where symptoms recur due to continuous exposure.
- This would be a temporary measure that carries risks of **systemic side effects** with repeated use and does not solve the fundamental problem of workplace allergen exposure.
*Add a leukotriene receptor antagonist to her current regimen*
- **Leukotriene receptor antagonists (LTRAs)** are an additional maintenance therapy for asthma, but they are secondary to the critical step of **exposure avoidance** in occupational asthma.
- Their use alone would not prevent the disease progression associated with persistent exposure to the **occupational sensitizer**.
Question 73: A 58-year-old man with newly diagnosed COPD attends a respiratory clinic for spirometry. His post-bronchodilator results show FEV1 1.8L (60% predicted), FVC 3.2L, and FEV1/FVC ratio 0.56. He is an active smoker with a 35 pack-year history and reports breathlessness on moderate exertion (MRC dyspnoea scale 2). He has had no exacerbations in the past year. What is the most appropriate initial pharmacological management according to NICE guidelines?
A. Long-acting beta-2 agonist (LABA) plus inhaled corticosteroid (ICS)
B. Long-acting muscarinic antagonist (LAMA) alone (Correct Answer)
C. Triple therapy with LABA, LAMA, and ICS
D. Short-acting beta-2 agonist (SABA) as required only
E. Long-acting beta-2 agonist (LABA) plus long-acting muscarinic antagonist (LAMA)
Explanation: ***Long-acting muscarinic antagonist (LAMA) alone*** - Per **NICE guidelines**, for patients with COPD who have persistent symptoms (MRC 2) but no history of exacerbations or features suggestive of asthma (e.g., eosinophilia), initial maintenance therapy should be **monotherapy** with either a **LAMA** or a **LABA**. - This patient fits this criteria, making **LAMA** a suitable first-line maintenance treatment to reduce breathlessness. *Long-acting beta-2 agonist (LABA) plus inhaled corticosteroid (ICS)* - **LABA + ICS** is typically reserved as initial maintenance therapy for patients with **asthma-COPD overlap syndrome** or those with **frequent exacerbations** and/or elevated blood eosinophil counts. - This patient has no history of exacerbations and no mention of asthmatic features, so adding an **ICS** increases the risk of side effects like pneumonia unnecessarily. *Triple therapy with LABA, LAMA, and ICS* - **Triple therapy** is a step-up treatment reserved for patients with persistent symptoms and/or recurrent **exacerbations** despite being on dual bronchodilator therapy (LABA+LAMA) or LABA+ICS. - It is not indicated as initial pharmacological management for a newly diagnosed patient without a history of exacerbations. *Short-acting beta-2 agonist (SABA) as required only* - While a **SABA** provides initial relief, this patient has **persistent breathlessness** (MRC dyspnoea scale 2) that impacts daily activity. - This indicates a need for regular **maintenance therapy** with a long-acting bronchodilator beyond just 'as required' short-acting agents. *Long-acting beta-2 agonist (LABA) plus long-acting muscarinic antagonist (LAMA)* - **Dual bronchodilation** (LABA+LAMA) is often considered a step-up therapy for patients whose symptoms are not adequately controlled with a single long-acting bronchodilator. - According to **NICE guidelines**, initial management for patients with persistent breathlessness but no exacerbations typically starts with **monotherapy** (LAMA or LABA).
Question 74: A 32-year-old woman presents to the Emergency Department with an acute asthma exacerbation. She receives nebulised salbutamol 5mg and ipratropium 500 micrograms with oxygen, oral prednisolone 40mg, and controlled oxygen therapy. Initial peak flow was 30% of her best. After 1 hour of treatment, repeat observations show: heart rate 128 bpm, respiratory rate 30 breaths/min, oxygen saturation 91% on 40% oxygen, peak flow 32% of best. She appears exhausted and is speaking in words only. Arterial blood gas shows: pH 7.28, PaCO2 6.8 kPa, PaO2 8.1 kPa, HCO3- 24 mmol/L on 40% oxygen. What is the most critical next step in management?
A. Commence intravenous magnesium sulphate 2g over 20 minutes
B. Start intravenous aminophylline infusion
C. Repeat nebulised bronchodilators continuously
D. Involve senior medical staff and ICU team immediately (Correct Answer)
E. Arrange transfer to high dependency unit for non-invasive ventilation
Explanation: ***Involve senior medical staff and ICU team immediately***
- The patient exhibits features of **near-fatal asthma**, specifically a **raised PaCO2 (6.8 kPa)** and respiratory **acidosis (pH 7.28)**, which indicate respiratory muscle fatigue and impending ventilatory failure.
- Clinical signs of **exhaustion**, inability to speak in full sentences, and persistent **hypoxia (SaO2 91% on 40% O2)** despite initial therapy necessitate immediate escalation for potential **intubation and mechanical ventilation**.
*Commence intravenous magnesium sulphate 2g over 20 minutes*
- While **IV magnesium** is indicated in life-threatening asthma not responding to initial treatment, it is an adjunctive therapy and should not delay immediate senior/ICU involvement given the critical ABG results.
- In the presence of **hypercapnia** and exhaustion, pharmacological bronchodilation alone is unlikely to prevent the need for more advanced respiratory support.
*Start intravenous aminophylline infusion*
- **Aminophylline** is a second-line bronchodilator used in severe exacerbations but has a narrow therapeutic index and requires careful monitoring.
- It is less effective than other therapies and does not address the immediate life-threatening risk of **respiratory arrest** or the need for ventilatory support seen in this patient.
*Repeat nebulised bronchodilators continuously*
- Continuous **nebulised beta-agonists** are standard for poor initial response, but they have already failed to significantly improve the patient's **peak flow (only 32%)** and clinical status after 1 hour.
- Relying solely on nebulizers in the setting of a **rising PaCO2** and clinical exhaustion is dangerous as it ignores the physiological signs of **ventilatory failure**.
*Arrange transfer to high dependency unit for non-invasive ventilation*
- **Non-invasive ventilation (NIV)** is generally **not recommended** in acute severe asthma as it can delay necessary **endotracheal intubation** and may exacerbate dynamic hyperinflation.
- Transfer to a High Dependency Unit (HDU) is insufficient; the severity of near-fatal asthma requires the full capabilities of an **Intensive Care Unit (ICU)** for invasive monitoring and ventilation.
Question 75: A 52-year-old woman with newly diagnosed asthma has been using a salbutamol inhaler as required and started on beclometasone 200 micrograms twice daily 8 weeks ago. She returns for review reporting she still experiences wheeze and breathlessness three times per week and is woken by symptoms once weekly. She uses her salbutamol inhaler 4-5 times per week. Her inhaler technique is checked and is good. What is the most appropriate next step in her asthma management?
A. Add leukotriene receptor antagonist (Correct Answer)
B. Add long-acting beta-2 agonist
C. Increase inhaled corticosteroid to high dose
D. Add long-acting muscarinic antagonist
E. Refer to respiratory specialist
Explanation: ***Add leukotriene receptor antagonist*** - This patient's symptoms (wheeze and breathlessness three times per week, woken by symptoms once weekly, salbutamol use 4-5 times per week) indicate **uncontrolled asthma** on a **low-dose inhaled corticosteroid (ICS)**. According to **NICE guidelines (NG80)** for adults, the next step in this scenario is to add a **leukotriene receptor antagonist (LTRA)**. - **LTRA** such as montelukast works by blocking leukotriene receptors, reducing airway inflammation and bronchoconstriction, offering an effective non-steroidal add-on option. *Add long-acting beta-2 agonist* - While **LABAs** are an important component of asthma management, current guidelines (e.g., NICE) generally recommend considering an **LTRA** as the first add-on therapy after **low-dose ICS** if asthma remains uncontrolled. - If the **LTRA** does not adequately control symptoms, then adding a **LABA** alongside the ICS (often as a fixed-dose combination inhaler) would be the subsequent step. *Increase inhaled corticosteroid to high dose* - Increasing the **ICS** to a high dose is typically reserved for patients whose asthma remains uncontrolled despite treatment with **ICS and LABA**, and sometimes an **LTRA**. - Escalating the **ICS dose** prematurely increases the risk of **dose-dependent local side effects** (e.g., oral candidiasis, dysphonia) and potential **systemic side effects** without fully exploring other add-on options. *Add long-acting muscarinic antagonist* - **Long-acting muscarinic antagonists (LAMAs)**, like tiotropium, are generally considered for **severe asthma** that remains uncontrolled despite optimal **ICS/LABA** therapy, usually at **Step 4 or 5** of the treatment ladder. - They are not indicated as a primary add-on therapy for patients who are only on low-dose **ICS** and have not yet tried an **LTRA** or **LABA**. *Refer to respiratory specialist* - Referral to a **respiratory specialist** is appropriate for patients with **difficult-to-treat asthma**, diagnostic uncertainty, or when management has reached **Step 4 or 5** and requires specialized input. - Before referral, primary care should optimize treatment following the stepwise pharmacological approach, which includes the addition of a **leukotriene receptor antagonist** at this stage.
Question 76: A 67-year-old man is diagnosed with acute pulmonary embolism confirmed on CT pulmonary angiogram. He has no contraindications to anticoagulation. His observations show: heart rate 118 bpm, blood pressure 98/65 mmHg, respiratory rate 26 breaths/min, oxygen saturation 91% on 4L oxygen. CTPA shows extensive bilateral pulmonary emboli with evidence of right ventricular dilatation (RV:LV ratio >1). Troponin is elevated at 150 ng/L. What risk category does this represent and what is the most appropriate immediate management?
A. Low risk PE; discharge with direct oral anticoagulant and outpatient follow-up
B. Intermediate-low risk PE; admit for monitoring and commence anticoagulation
C. Intermediate-high risk PE; admit to high-dependency unit and consider thrombolysis (Correct Answer)
D. High risk PE; commence thrombolysis immediately
E. Intermediate risk PE; commence therapeutic anticoagulation and arrange outpatient echocardiography
Explanation: ***Intermediate-high risk PE; admit to high-dependency unit and consider thrombolysis***- This patient is classified as **intermediate-high risk** because he is **hemodynamically stable** (BP 98/65 mmHg) but has both **right ventricular dysfunction** (RV:LV ratio >1 on CTPA) and **myocardial injury** (elevated troponin at 150 ng/L).- Management requires admission to a **high-dependency unit (HDU)** for close monitoring, as these patients have a significant risk of clinical deterioration where **thrombolytic therapy** might become necessary. *Low risk PE; discharge with direct oral anticoagulant and outpatient follow-up*- **Low risk PE** is characterized by hemodynamic stability with **no evidence of RV dysfunction** or **myocardial injury** (normal troponin and no RV strain).- This patient's signs of **hypoxia**, **tachycardia**, positive **troponin**, and **RV dilatation** preclude outpatient management and indicate a higher risk.*Intermediate-low risk PE; admit for monitoring and commence anticoagulation*- **Intermediate-low risk PE** is typically assigned when a patient is hemodynamically stable and has *only one* marker of severity (either **RV dysfunction** *or* **elevated biomarkers**).- Since this patient exhibits *both* elevated troponin and RV strain on CTPA, he falls into the higher intermediate-high risk category, necessitating more intensive monitoring than standard ward admission.*High risk PE; commence thrombolysis immediately*- **High risk PE** (also known as massive PE) is defined by **hemodynamic instability**, such as persistent hypotension (SBP <90 mmHg) or cardiogenic shock.- Although the patient's blood pressure is borderline, he is currently **hemodynamically stable**, meaning immediate systemic thrombolysis is not indicated unless his condition deteriorates to shock. *Intermediate risk PE; commence therapeutic anticoagulation and arrange outpatient echocardiography*- While **therapeutic anticoagulation** is crucial, managing a patient with acute **intermediate-high risk PE** with outpatient echocardiography is inappropriate given their physiological distress.- The presence of **RV strain** has already been confirmed by CTPA, and the immediate priority is inpatient monitoring and potential escalation of therapy rather than further elective imaging.
Question 77: A 35-year-old woman who is 28 weeks pregnant presents with sudden onset breathlessness and right-sided pleuritic chest pain. She is haemodynamically stable with oxygen saturations of 96% on room air. Pulmonary embolism is suspected. Chest X-ray is normal. What is the most appropriate imaging investigation to diagnose PE in this patient?
A. CT pulmonary angiogram with abdominal shielding
B. Lower limb compression ultrasound Doppler
C. MR pulmonary angiogram
D. No imaging required, treat empirically based on clinical suspicion
E. Ventilation-perfusion (V/Q) scan (Correct Answer)
Explanation: ***Ventilation-perfusion (V/Q) scan***- For a pregnant patient with suspected **pulmonary embolism (PE)** and a **normal chest X-ray**, a V/Q scan is the preferred first-line imaging investigation according to **RCOG and NICE guidelines**.- It is preferred over CTPA in this scenario because it carries a significantly lower risk of **maternal breast radiation**, which is crucial in reducing the lifetime risk of **breast cancer**.*CT pulmonary angiogram with abdominal shielding*- While CTPA is highly accurate, it delivers a much higher radiation dose to **maternal breast tissue** (up to 20-100 times more than V/Q scans).- CTPA is generally reserved as the first-line investigation in pregnancy only if the **chest X-ray is abnormal** or if V/Q scanning is not available.*Lower limb compression ultrasound Doppler*- This test is used to identify a **deep vein thrombosis (DVT)**; if positive in a patient with respiratory symptoms, it can justify anticoagulation without further chest imaging.- However, a negative ultrasound does not exclude a **pulmonary embolism**, and it is not the definitive imaging investigation for diagnosing PE itself.*MR pulmonary angiogram*- MRI is currently **not recommended** for the routine diagnosis of PE in pregnancy due to limited sensitivity and lack of large-scale validation.- It also often requires **gadolinium contrast**, which is generally avoided in pregnancy unless absolutely necessary as it can cross the placenta.*No imaging required, treat empirically based on clinical suspicion*- Empirical treatment should be started immediately if PE is suspected, but it must be followed by **objective imaging** to confirm the diagnosis.- Definitive diagnosis is essential to avoid the risks of **long-term anticoagulation** and to guide management during labor and the postpartum period.
Question 78: A 42-year-old woman presents with left-sided pleuritic chest pain and mild breathlessness for 24 hours. She takes no regular medications apart from the combined oral contraceptive pill. Her Wells score for PE is calculated as 1.5 (PE unlikely). Observations are normal except for heart rate 92 bpm. D-dimer is reported as 650 ng/ml (elevated, normal <500 ng/ml). What is the most appropriate next step in management?
A. Commence therapeutic dose low molecular weight heparin and arrange CT pulmonary angiogram (Correct Answer)
B. Reassure and discharge as Wells score indicates PE is unlikely
C. Repeat D-dimer in 24 hours
D. Arrange outpatient V/Q scan within 1 week
E. Perform arterial blood gas analysis
Explanation: ***Commence therapeutic dose low molecular weight heparin and arrange CT pulmonary angiogram***
- In patients with a **Wells score ≤ 4 (PE unlikely)**, an **elevated D-dimer** necessitates definitive imaging via **CT pulmonary angiogram (CTPA)** to exclude pulmonary embolism.
- **Therapeutic anticoagulation** should be initiated immediately if a delay in imaging is anticipated to reduce the risk of further **thromboembolic events**.
*Reassure and discharge as Wells score indicates PE is unlikely*
- A **Wells score** of 1.5 only indicates that PE is **unlikely**, but it does not rule it out; a **positive D-dimer** in this context requires further investigation.
- Discharging a patient with an **elevated D-dimer** and risk factors (COCP) for PE is **unsafe** and could lead to significant adverse outcomes.
*Repeat D-dimer in 24 hours*
- The initial D-dimer is already **elevated**; repeating it will not change the diagnostic pathway, which mandates moving directly to **definitive imaging**.
- Delaying the diagnosis and potential treatment for a serious condition like PE by waiting for repeat blood tests is **not appropriate management**.
*Arrange outpatient V/Q scan within 1 week*
- Suspected pulmonary embolism is an **acute medical emergency** requiring prompt evaluation; waiting one week for an outpatient V/Q scan is **dangerously prolonged**.
- **CTPA** is generally the preferred first-line imaging modality for acute PE, especially in patients without contraindications to contrast.
*Perform arterial blood gas analysis*
- While **arterial blood gas (ABG)** analysis might show **hypoxia** or **hypocapnia**, it is not sufficiently sensitive or specific to diagnose or exclude PE.
- Performing an ABG should not delay the critical steps of initiating **anticoagulation** or arranging **definitive radiological imaging**.
Question 79: A 58-year-old woman presents to the Emergency Department with sudden onset right-sided pleuritic chest pain and breathlessness that started 2 hours ago. She underwent a right total hip replacement 10 days ago. Observations: heart rate 110 bpm, blood pressure 128/82 mmHg, respiratory rate 22 breaths/min, oxygen saturation 94% on room air, temperature 36.8°C. Chest examination is unremarkable. ECG shows sinus tachycardia. What is the most appropriate initial investigation?
A. CT pulmonary angiogram (Correct Answer)
B. Chest X-ray
C. Ventilation-perfusion (V/Q) scan
D. D-dimer assay
E. Echocardiography
Explanation: ***CT pulmonary angiogram***
- A **CT pulmonary angiogram (CTPA)** is the gold standard imaging modality for diagnosing **pulmonary embolism (PE)** because it provides direct visualization of the pulmonary vasculature.
- Given the patient's high clinical probability (recent total hip replacement, sudden onset pleuritic chest pain and breathlessness, tachycardia), a CTPA is the most appropriate initial definitive investigation.
*Chest X-ray*
- A **Chest X-ray** is typically performed to rule out other causes of chest pain such as **pneumothorax** or pneumonia, but it is often normal in the setting of an acute PE.
- While it may be part of the initial workup, it is not diagnostic for PE and should not delay more specific imaging like a CTPA in a high-suspicion case.
*Ventilation-perfusion (V/Q) scan*
- A **V/Q scan** is a secondary alternative used primarily when **intravenous contrast** or significant radiation exposure is contraindicated, such as in patients with **severe renal impairment** or contrast allergy.
- It is generally less sensitive than CTPA and can often yield **indeterminate results**, making it a less preferred first-line investigation for acute PE in patients who can undergo CTPA.
*D-dimer assay*
- A **D-dimer** has a high negative predictive value, useful for ruling out PE in patients with a low clinical probability, but it is inappropriate as an initial investigation here because the patient's clinical probability of PE is **"likely"** (e.g., Wells score likely high).
- Following recent **major surgery**, the D-dimer is often elevated due to post-operative inflammation and clot healing, making it a non-specific and unhelpful test for diagnosing PE in this context.
*Echocardiography*
- **Echocardiography** is not used to directly diagnose PE itself, but it can identify signs of **right ventricular strain** or pulmonary hypertension in cases of massive or submassive PE.
- It is generally reserved for **hemodynamically unstable** patients who are too unstable to be transported for a CTPA, or to assess the severity and impact of PE on cardiac function.
Question 80: A 68-year-old man is admitted with severe community-acquired pneumonia (CURB-65 score 4). He is started on intravenous co-amoxiclav and clarithromycin. Blood cultures are taken. Despite 48 hours of treatment, he remains febrile with persistent hypoxia requiring 6L oxygen. Chest X-ray shows progression of consolidation with a small pleural effusion. Urinary Legionella antigen is negative. Sputum microscopy shows Gram-positive diplococci and culture is awaited. What is the most appropriate modification to antibiotic therapy?
A. Add intravenous levofloxacin to current regimen (Correct Answer)
B. Stop clarithromycin and continue co-amoxiclav alone
C. Add intravenous teicoplanin for MRSA cover
D. Switch to intravenous piperacillin-tazobactam and gentamicin
E. Continue current antibiotics for a further 48 hours before reviewing
Explanation: ***Add intravenous levofloxacin to current regimen***
- In **severe community-acquired pneumonia (CAP)** with clinical failure (persistent fever, worsening hypoxia, and radiological progression), broadening coverage to include a **fluoroquinolone** provides dual coverage for **Streptococcus pneumoniae** and ensures robust coverage for diverse **atypical pathogens**.
- **Levofloxacin** is recommended in non-responding severe CAP because a negative urinary antigen does not exclude all **Legionella** serogroups, and it effectively targets potential resistant strains of **pneumococcus**.
*Stop clarithromycin and continue co-amoxiclav alone*
- Discontinuing the macrolide would lose essential coverage for **atypical organisms** (e.g., *Mycoplasma*, *Chlamydophila*, *Legionella*), which is crucial in severe CAP regardless of initial negative atypical tests.
- This approach represents a **de-escalation** of therapy in a patient who is actively deteriorating, which is contraindicated by the worsening hypoxia and radiographic progression.
*Add intravenous teicoplanin for MRSA cover*
- Coverage for **MRSA** is generally reserved for patients with specific risk factors, such as prior colonization, recent influenza infection, or **cavitating pneumonia**, none of which are explicitly mentioned here.
- The sputum Gram stain showed **Gram-positive diplococci**, which is characteristic of *Streptococcus pneumoniae*, not the Gram-positive cocci in clusters typical of *Staphylococcus aureus* (including MRSA).
*Switch to intravenous piperacillin-tazobactam and gentamicin*
- This regimen is typically indicated for **hospital-acquired pneumonia (HAP)**, **ventilator-associated pneumonia (VAP)**, or patients at high risk for **Pseudomonas aeruginosa**, which is not the standard empirical profile for CAP.
- **Gentamicin** carries significant risks of nephrotoxicity and ototoxicity and is rarely used as a first-line modification for community-acquired respiratory infections unless multi-drug resistance is confirmed.
*Continue current antibiotics for a further 48 hours before reviewing*
- Maintaining the status quo is inappropriate in the presence of clear **clinical deterioration**, indicated by persistent fever, increased oxygen requirements, and progression of **pulmonary consolidation**.
- Severe CAP with a **CURB-65 score of 4** requires proactive management and prompt treatment escalation if improvement is not observed within the initial 48-72 hours.
