Regarding pneumonia caused by methicillin-resistant S. aureus (MRSA), all of the following statements are correct EXCEPT:
Answer: D: Virulent strains of community-associated methicillin-resistant S. aureus (CA-MRSA) are increasingly becoming more prevalent in many parts of Australia including Queensland, NSW and the ACT. These strains can cause severe skin infections such as furunculosis, as well as rapidly fatal severe CAP. This severe pneumonia usually occurs in previously healthy children and young adults with a history of furunculosis or folliculitis. Please note that this is entirely a community-acquired infection. Usually, there is a history of family members affected by the same skin infection. These virulent strains produce a potent necrotizing toxin. Rapidly progressive septic shock is common. The mortality rate has been described as 37% within 48 hours from presentation. To maximize the survival an early high index of suspicion, early treatment with appropriate antibiotics and rapid interventions for correction of shock are essential. The current national recommendations for empirically treating suspected MRSA pneumonia are intravenous vancomycin and a beta lactam antibiotic (flu/ dicloxacillin or cephalothin).
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Regarding aspiration pneumonitis, which ONE of the following statements is TRUE?
Answer: B: Aspiration pneumonitis is a chemical pneumonitis due to aspiration of sterile gastric contents with gastric acid. This causes direct lung injury and noncardiogenic pulmonary oedema. This may lead to progressively worsening respiratory symptoms and subsequently acute respiratory distress syndrome (ARDS). Aspiration pneumonitis is the most severe form of pulmonary aspiration (see next answer). Most patients present early (within a few hours) and the initial CXR is usually abnormal. Patient may develop ARDS and respiratory failure within 2–5 hours after aspiration. The pneumonitis is not due to infection; however, secondary bacterial infection can occur later.
Regarding the management of an elderly patient with suspected pulmonary aspiration, which ONE of the following statements is TRUE?
Answer: B: Clinical features of pulmonary aspiration are due to three mechanisms:
Routine use of antibiotic therapy after suspected aspiration is controversial. If the suspected aspiration is of a minor degree, patients can be observed without initial antibiotic treatment. Aspiration pneumonia due to secondary bacterial infection can be diagnosed when the patient has typical symptoms of pneumonia, with radiological changes indicating that process. The CXR changes tend to occur in the dependent segments of the lung; in a supine patient, posterior segments of the upper lobes and superior segments of the lower lobes and, if erect, in the basal segments. The changes may appear as a bronchopneumonia or, in case of delayed presentation, may show as a lung abscess (i.e. cavitory lesion with an air fluid level).
The indications for antibiotic therapy in suspected aspiration are:
Rigid bronchoscopy is indicated when aspiration of particulate matter (in gastric content, vegetable matter, teeth, etc.). The patient may present with small airway obstruction and resultant distal atelectasis and hypoxia. There is no evidence to suggest that steroids are beneficial in pulmonary aspiration. Most elderly patients require observation in hospital (even if asymptomatic) to detect any deterioration with development of bronchospasm, respiratory distress, hypoxia and fever.
Regarding a patient with diagnosed bronchiectasis presenting to the ED with recent onset cough and increasing dyspnoea, which ONE of the following statements is TRUE?
Answer: A: Bronchiectasis is described as an abnormal and permanent dilatation of bronchi and is most often due to an infectious process causing inflammation and destruction of the bronchial walls. This usually affects older patients and can be focal or diffuse. Typical offending organisms include viruses, mainly adenovirus and influenza, and bacteria such as S. aureus, Klebsiella, anaerobes, tuberculosis and Bordetella pertussis. Many other causes have been described including alpha 1 antitrypsin deficiency.
AS a result of reduced host defence mechanisms (due to destruction of air passages), a perpetual cycle of recurrent infections and further inflammation, obstruction and destruction occurs. Secretions accumulate and bacteria colonize obstructed air passages. The organisms found most typically include Haemophilus species and Pseudomonas species. These organisms can cause ongoing damage and episodic infectious exacerbations.
The reason for ED presentations is often acute exacerbations due to respiratory tract infections; antibiotic therapy is the mainstay of management in acute exacerbations. Sputum cultures done when the patient is stable and, ideally not taking antibiotics, can be used to guide the management of their next exacerbation. As the respiratory tract is often colonized with Pseudomonas aeruginosa a review of microbiology results of previous sputum cultures is important and empiric antibiotic treatment should be based on the previous culture results. Infection with Pseudomonas aeruginosa is associated with the greatest rate of lung function deterioration and the worst quality of life. Bronchial hyperreactivity and reversible obstruction is relatively common in bronchiectasis patients and bronchodilator therapy may be helpful to relieve the reversible obstruction and also may aid in the clearance of secretions. Improved clearance of tracheobronchial secretions should be attempted with chest physiotherapy using a variety of methods. The use of mucolytic agents to thin secretions has not been proven to be beneficial. However, nebulized hypertonic saline and inhaled mannitol appear promising in assisting sputum clearance.
Patients with bronchiectasis are at high risk for haemoptysis, sometimes massive, due to hypertrophied bronchial arteries.
Regarding recurrence of a spontaneous pneumothorax, which ONE of the following statements is TRUE?
Answer: D Cessation of cigarette smoking has been shown to reduce the risk of recurrence of a pneumothorax. About 20–30% of the primary spontaneous and 40–50% of the secondary spontaneous pneumothoraces recur. Resolution of a pneumothorax or the rate of reexpansion of the lung has no bearing on recurrence. The recurrence is prevented by definitive treatment. Definitive treatment is usually indicated after the first recurrence, but for any patient in whom it is critical to prevent a recurrence (e.g. airline pilots) it should be offered following the first pneumothorax.
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