MRCP Part 1 Respiratory Medicine 2 — Questions and Answers
Question 1: A 50-year-old man with a 30-pack-year smoking history presents with haemoptysis and a right hilar mass on CXR. CT confirms a central lung mass with mediastinal lymphadenopathy. What is the most likely histological type?
- Adenocarcinoma
- Squamous cell carcinoma (Correct answer)
- Small cell lung cancer
- Mesothelioma
Correct answer: Squamous cell carcinoma
Squamous cell carcinoma is the most common central lung tumour in smokers, arising from bronchial epithelium. It is associated with haemoptysis, central location, and hilar masses. Adenocarcinoma is more common peripherally. Small cell is central but has distinct paraneoplastic syndromes.
Question 2: A patient with small cell lung cancer presents with hyponatraemia (Na 118 mmol/L) and inappropriately concentrated urine. What paraneoplastic syndrome does this represent?
- Cushing syndrome
- SIADH (Correct answer)
- Eaton-Lambert syndrome
- Hypercalcaemia of malignancy
Correct answer: SIADH
SIADH (Syndrome of Inappropriate Antidiuretic Hormone secretion) is the most common paraneoplastic syndrome in small cell lung cancer. Ectopic ADH production causes dilutional hyponatraemia with inappropriately concentrated urine (urine osmolality >100 mOsm/kg despite low plasma osmolality).
Question 3: In obstructive sleep apnoea (OSA), which investigation is the gold standard for diagnosis?
- Overnight oximetry alone
- Epworth sleepiness scale score
- Polysomnography (full overnight sleep study) (Correct answer)
- CT neck
Correct answer: Polysomnography (full overnight sleep study)
Full polysomnography (overnight sleep study) measuring airflow, respiratory effort, oxygen saturation, EEG, EMG, and ECG is the gold standard for diagnosing OSA and characterising its severity (AHI). Limited respiratory polygraphy may be used in straightforward cases.
Question 4: Which spirometric pattern is characteristic of idiopathic pulmonary fibrosis?
- Obstructive: reduced FEV1/FVC ratio
- Restrictive: reduced FVC, normal or increased FEV1/FVC ratio (Correct answer)
- Mixed: reduced FEV1/FVC with reduced TLC
- Obstructive with reversibility post-bronchodilator
Correct answer: Restrictive: reduced FVC, normal or increased FEV1/FVC ratio
Idiopathic pulmonary fibrosis causes a restrictive pattern: reduced FVC, reduced TLC, preserved or elevated FEV1/FVC ratio. The fibrosis stiffens the lung, reducing volume but not obstructing flow proportionally. DLCO is also characteristically reduced.
Question 5: What is the first-line antibiotic for a hospitalised patient with moderate community-acquired pneumonia according to UK NICE guidelines?
- Clarithromycin monotherapy
- Co-amoxiclav
- Amoxicillin plus a macrolide (e.g., clarithromycin) (Correct answer)
- Ceftriaxone plus vancomycin
Correct answer: Amoxicillin plus a macrolide (e.g., clarithromycin)
For moderate CAP requiring hospitalisation, UK NICE guidelines recommend amoxicillin plus a macrolide (clarithromycin or azithromycin) to cover both typical organisms (pneumococcus) and atypical pathogens (Mycoplasma, Legionella, Chlamydophila).
Question 6: A 40-year-old Afro-Caribbean woman presents with bilateral hilar lymphadenopathy, erythema nodosum, and arthralgia. Serum ACE is elevated. What is the most likely diagnosis?
- Lymphoma
- Tuberculosis
- Sarcoidosis (Correct answer)
- Systemic lupus erythematosus
Correct answer: Sarcoidosis
This is Löfgren syndrome, an acute presentation of sarcoidosis characterised by bilateral hilar lymphadenopathy, erythema nodosum, fever, and polyarthralgia. It carries a good prognosis. Elevated serum ACE and raised calcium support the diagnosis. Sarcoidosis is more prevalent in Afro-Caribbean populations.
MRCP Part 1 Respiratory Medicine 2
A 50-year-old man with a 30-pack-year smoking history presents with haemoptysis and a right hilar mass on CXR.
CT confirms a central lung mass with mediastinal lymphadenopathy.
What is the most likely histological type?