A 35-year-old female presents with shortness of breath. The following blood gases are obtained on room air:
Which one of the following is the least likely cause?
Correct Answer A: The question asks for the least likely cause of a respiratory alkalosis. Salicylate, not opiate, poisoning is associated with a respiratory alkalosis. Opiate overdose would lead to respiratory depression and hence a respiratory acidosis.
Respiratory alkalosis: Common causes:
*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.
A 74-year-old woman has a chest x-ray organized by her GP due to a chronic cough. The chest x-ray shows a cavity in the left upper zone inside of which there is a solid mass. An aspergilloma is suspected.
What is the most appropriate next test?
Correct Answer B:
Aspergilloma:
An aspergilloma is a fungus ball which often colonizes an existing lung cavity (e.g. secondary to TB, lung cancer or cystic fibrosis).
Usually asymptomatic but features may include:
Investigations:
A 24-year-old man who has been discharged following admission for a spontaneous pneumothorax ask for advice about flying. During his stay in hospital the pneumothorax was aspirated and a check x-ray revealed no residual air.
What is the earliest time he should fly?
Correct Answer D:
Fitness to fly: The Civil Aviation Authority (CAA) has issued guidelines on air travel for people with medical conditions; please see the link provided.
Cardiovascular disease:
Respiratory disease:
Pregnancy:
Surgery:
Haematological disorders:
When assessing a patient with suspected chronic obstructive pulmonary disease, which one of the following is least relevant?
Correct Answer D: Peak expiratory flow is of no value in the diagnosis of COPD.
COPD: investigation and diagnosis:
NICE recommend considering a diagnosis of COPD in patients over 35 years of age who are smokers or ex-smokers and have symptoms such as exertional breathlessness, chronic cough or regular sputum production.
The following investigations are recommended in patients with suspected COPD:
The severity of COPD is categorized using the FEV1*:
Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of airflow obstruction.
*Note that the grading system has changed following the 2010 NICE guidelines. If the FEV1 is greater than 80% predicted but the post-bronchodilator FEV1/FVC is < 0.7 then this is classified as Stage 1 - mild.
**Symptoms should be present to diagnose COPD in these patients.
A 19-year-old with 'brittle asthma' is seen in clinic. Three weeks ago she started taking prednisolone 15mg od as her asthma was poorly controlled on beclomethasone dipropionate 800 mcg bd., salmeterol, oral montelukast and salbutamol as required.
What should happen with regards to inhaled steroids?
Correct Answer C: Even when patients are on oral prednisolone they should continue high-dose inhaled corticosteroids.
Asthma: stepwise management in adults:
The management of stable asthma is now well established with a step-wise approach:
*beclomethasone dipropionate or equivalent.
Additional notes: Leukotriene receptor antagonists:
Fluticasone is more lipophilic and has a longer duration of action than beclomethasone Hydrofluoroalkane is now replacing chlorofluorocarbon as the propellant of choice. Only half the usually dose is needed with hydrofluoroalkane due to the smaller size of the particles.
Long acting B2-agonists acts as bronchodilators but also inhibit mediator release from mast cells. Recent metaanalysis showed adding salmeterol improved symptoms compared to doubling the inhaled steroid dose.
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