Question 21#

A 46-year-old female with a history of rheumatoid arthritis is investigated due to progressive shortness of breath. She is currently treated with methotrexate and ibuprofen. The following results are obtained from spirometry:

FEV1/FVC 45%

What is the most likely cause of the dyspnoea?

A. Bronchiolitis obliterans

Correct Answer A: The spirometry reveals an obstructive picture which would be in keeping with bronchiolitis obliterans.

Rheumatoid arthritis:

Respiratory manifestations:
A variety of respiratory problems may be seen in patients with rheumatoid arthritis:

• Pulmonary fibrosis
• Pleural effusion
• Pulmonary nodules
• Bronchiolitis obliterans
• Complications of drug therapy e.g. methotrexate pneumonitis
• Pleurisy
• Caplan's syndrome - massive fibrotic nodules with occupational coal dust exposure
• Infection (possibly atypical) secondary to immunosuppression

Question 22#

A 62-year-old female with a 40 pack year history of smoking is investigated for a chronic cough associated with haemoptysis. Bronchoscopy reveals a small 1 cm tumour confined to the right main bronchus. A biopsy taken shows small cell lung cancer.

What is the most appropriate management?

A. Laser therapy

Correct Answer B: Surgery plays little role in the management of small cell lung cancer, with chemotherapy being the mainstay of treatment. Adjuvant radiotherapy is also now given in patients with limited disease.

Lung cancer: small cell:

Features:

• Usually central
• Arise from APUD* cells
• Associated with ectopic ADH, ACTH secretion
• ADH --> hyponatraemia
• ACTH --> Cushing's syndrome
• ACTH secretion can cause bilateral adrenal hyperplasia, the high levels of cortisol can lead to hypokalaemic alkalosis
• Lambert-Eaton syndrome: antibodies to voltage gated calcium channels causing myasthenic like syndrome 

Management:

• Usually metastatic disease by time of diagnosis
• Surgery: only used for debulking
• Most patients with limited disease now receive a combination of chemotherapy and radiotherapy
• Patients with more extensive disease are offered palliative chemotherapy

*an acronym for:

• Amine - high amine content
• Precursor Uptake - high uptake of amine precursors
• Decarboxylase - high content of the enzyme decarboxylase

Question 23#

A 72-year-old man who is known to have chronic kidney disease stage 4 is admitted to the Emergency Department. Since yesterday he has felt short-of-breath on exertion and has been coughing up blood. On examination he tachycardic at 110/min with a normal chest examination.

What is the most suitable initial imaging investigation to exclude a pulmonary embolism?

A. Ventilation-perfusion scan

Correct Answer A: Computed tomographic pulmonary angiography (CTPA) is now used first-line to investigate the possibility of pulmonary embolism. Patients with renal impairment however should be offered Ventilation-perfusion (V/Q) scans as the contrast media used during CTPAs is nephrotoxic.

Pulmonary embolism investigation:
2012 NICE guidelines

All patients with symptoms or signs suggestive of a PE should have a history taken, examination performed and a chest x-ray to exclude other pathology.

If a PE is still suspected a two-level PE Wells score should be performed:

Clinical probability simplified scores:

• PE likely - more than 4 points
• PE unlikely - 4 points or less

If a PE is 'likely' (more than 4 points) arrange an immediate computed tomography pulmonary angiogram (CTPA). If there is a delay in getting the CTPA then give low-molecular weight heparin until the scan is performed.

If a PE is 'unlikely' (4 points or less) arranged a D-dimer test. If this is positive arrange an immediate computed tomography pulmonary angiogram (CTPA). If there is a delay in getting the CTPA then give low-molecular weight heparin until the scan is performed.

If the patient has an allergy to contrast media or renal impairment a V/Q scan should be used instead of a CTPA.

CTPA or V/Q scan?

The British Thoracic Society (BTS) published guidelines back in 2003 on the management of patients with suspected pulmonary embolism (PE). Key points from the guidelines include:

• Computed tomographic pulmonary angiography (CTPA) is now the recommended initial lung imaging modality for non-massive PE. Advantages compared to V/Q scans include speed, easier to perform out of- hours, a reduced need for further imaging and the possibility of providing an alternative diagnosis if PE is excluded
• If the CTPA is negative then patients do not need further investigations or treatment for PE
• Ventilation-perfusion scanning may be used initially if appropriate facilities exist, the chest x-ray is normal, and there is no significant symptomatic concurrent cardiopulmonary disease 

D-dimers:

• Sensitivity = 95-98%, but poor specificity

ECG:

• The classic ECG changes seen in PE are a large S wave in lead I, a large Q wave in lead III and an inverted T wave in lead III - 'S1Q3T3'. However this change is seen in no more than 20% of patients
• Right bundle branch block and right axis deviation are also associated with PE
• Sinus tachycardia may also be seen 

V/Q scan:

• Sensitivity = 98%; specificity = 40% - high negative predictive value, i.e. if normal virtually excludes PE
• Other causes of mismatch in V/Q include old pulmonary embolisms, AV malformations, vasculitis, previous radiotherapy
• COPD gives matched defects

CTPA:

• Peripheral emboli affecting subsegmental arteries may be missed

Pulmonary angiography:

• The gold standard
• Significant complication rate compared to other investigations

Question 24#

A 62-year-old man who is investigated for haemoptysis is found to have squamous cell lung cancer.

Which one of the following is a contraindication to surgery? 

A. Pleural effusion

Correct Answer B: Contraindications to lung cancer surgery include SVC obstruction, FEV < 1.5, MALIGNANT pleural effusion, and vocal cord paralysis.

If one of the options was 'malignant pleural effusion', rather than just 'pleural effusion' (which may be reactive), then this would also be a contraindication.

Lung cancer: non-small cell management:

Management:

• Only 20% suitable for surgery
• Mediastinoscopy performed prior to surgery as CT does not always show mediastinal lymph node involvement
• Curative or palliative radiotherapy
• Poor response to chemotherapy 

Surgery contraindications:

• Assess general health
• Stage IIIb or IV (i.e. metastases present)
• FEV1 < 1.5 litres is considered a general cut-off point*
• Malignant pleural effusion
• Tumour near hilum
• Vocal cord paralysis
• SVC obstruction

* However if FEV1 < 1.5 for lobectomy or < 2.0 for pneumonectomy then some authorities advocate further lung function tests as operations may still go ahead based on the results.

Question 25#

A 24-year-old female with a history of anxiety is taken to the Emergency Department following an acute onset of shortness of breath. On examination the chest is clear to auscultation but the respiratory rate is raised at 40 breaths per minute. A diagnosis of hyperventilation secondary to anxiety is suspected.

Which of the following arterial blood gas results (taken on room air) are consistent with this?

A. pH = 7.56; pCO₂ = 2.9 kPa; pO₂ = 10.1 kPa

Correct Answer D: Hyperventilation will result in carbon dioxide being 'blown off', causing an alkalosis. Whilst the gases in answer A show a respiratory alkalosis the hypoxia could not be explained by hyperventilation.

Respiratory alkalosis:

Common causes:

• Anxiety leading to hyperventilation
• Pulmonary embolism
• Salicylate poisoning*
• CNS disorders: stroke, subarachnoid haemorrhage, encephalitis
• High altitude
• Pregnancy

*Salicylate overdose leads to a mixed respiratory alkalosis and metabolic acidosis. Early stimulation of the respiratory center leads to a respiratory alkalosis whilst later the direct acid effects of salicylates (combined with acute renal failure) may lead to an acidosis