A 67-year-old female is referred to the acute medical unit with an infective exacerbation of COPD. Despite maximal medical therapy the arterial blood gases continue to show type II respiratory failure. You are asked to consider non-invasive ventilation.
At what pH is the patient most likely to receive benefit from non-invasive ventilation?
Correct Answer D: The evidence surrounding the use of NIV in COPD shows that patients with a pH in the range of 7.25-7.35 achieve the most benefit. If the pH is < 7.25 then invasive ventilation should be considered if appropriate.
Non-invasive ventilation: The British Thoracic Society (BTS) published guidelines in 2002 on the use of non-invasive ventilation in acute respiratory failure. Following these the Royal College of Physicians published guidelines in 2008.
Non-invasive ventilation - key indications:
Recommended initial settings for bi-level pressure support in COPD:
A 35-year-old female with sarcoidosis is started on a course of prednisolone. Which one of the following is a suitable indication for commencing steroid therapy in such patients?
Correct Answer C:
Sarcoidosis: management:
Sarcoidosis is a multisystem disorder of unknown aetiology characterized by non-caseating granulomas. It is more common in young adults and in people of African descent.
Indications for steroids:
A 54-year-old man is investigated for a chronic cough. A chest x-ray arranged by his GP shows a suspicious lesion in the right lung. He has no past history of note and is a life-long non-smoker. An urgent bronchoscopy is arranged which is normal.
What is the most likely diagnosis?
The clues are the absence of a smoking history and normal bronchoscopy, which suggests a peripherally located lesion.
Lung cancer: non-small cell:
There are three main subtypes of non-small cell lung cancer:
1- Squamous cell cancer:
2- Adenocarcinoma:
3- Large cell lung carcinoma
A 45-year-old dairy farmer presents with increasing shortness-of-breath on exertion. He is a nonsmoker and has no respiratory history of note. His symptoms seem to become much worse when he is around the farm and are associated with chest tightness and a non-productive cough. A diagnosis of extrinsic allergic alveolitis is suspected.
Which one of the following is most likely to be responsible?
Correct Answer C: Contaminated hay is the most common source of Saccharopolyspora rectivirgula which is responsible for Farmer's lung.
Extrinsic allergic alveolitis:
Extrinsic allergic alveolitis (EAA, also known as hypersensitivity pneumonitis) is a condition caused by hypersensitivity induced lung damage due to a variety of inhaled organic particles. It is thought to be largely caused by immune-complex mediated tissue damage (type III hypersensitivity) although delayed hypersensitivity (type IV) is also thought to play a role in EAA, especially in the chronic phase.
Examples:
Presentation:
Investigation:
*Here the terminology is slightly confusing as thermophilic actinomycetes is an umbrella term covering strains such as Micropolyspora faeni.
A 62-year-old female is admitted with a suspected infective exacerbation of COPD. A chest x-ray shows no evidence of consolidation.
What is the most likely causative organism?
Correct Answer B: If the patient had pneumonia then Streptococcus pneumoniae would be the most likely causative organism. However, the chest x-ray shows no evidence of consolidation making a diagnosis of pneumonia unlikely.
Haemophilus influenzae is the most common cause of infective exacerbations of COPD. The patient should be treated with a course of amoxicillin or a tetracycline together with prednisolone.
COPD: management of acute exacerbations:
The most common bacterial organisms that cause infective exacerbations of COPD are:
Respiratory viruses account for around 30% of exacerbations, with the human rhinovirus being the most important pathogen.
NICE guidelines from 2010 recommend the following:
Click to expand