Respiratory disease

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13 Respiratory disease

Approach to the patient

Haemoptysis should always be investigated. Often, the diagnosis can be made from a CXR, but a normal CXR does not exclude disease. Bronchoscopy is only diagnostic in about 5% of patients with haemoptysis and a normal CXR.

For management of a massive haemoptysis, see Box 13.1.

Treatment of cough is the treatment of the underlying cause and often symptomatic. Anti-tussives include codeine linctus 5–10 mL 3–4 times daily or pholcodine 5 mL 3–4 times daily. There is no evidence that expectorants work but simple linctus 5 mL 3–4 times daily is comforting.

Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a slowly progressive condition predominantly caused by smoking and is the sixth commonest cause of death worldwide; its incidence is increasing. It is characterized by airflow limitation, which is not fully reversible. The lungs have an abnormal inflammatory response to inhaled particles or gases, resulting in airflow limitation. The GOLD (Global Initiative for Chronic Obstructive Lung Disease, WHO) criteria for the diagnosis of lung disease are shown in Table 13.1.

Clinical features

COPD is suspected on the basis of chronic progressive symptoms, usually with a smoking history of more than 20 pack years (1 pack year = 20 cigarettes per day for 1 year). It is supported by objective evidence of airflow limitation (or obstruction), usually with spirometry, which does not return to normal with treatment.

Diagnosis and investigations

The diagnosis of COPD is usually clinical, supported by the presence of airflow obstruction on spirometry.

Management

With the exception of smoking cessation, the aims of COPD treatment are symptomatic relief and the prevention of exacerbations and complications. No existing medication has been shown to modify decline in lung function.

Smoking cessation

This is vital at any age or stage of the disease. An aggressive smoking cessation programme has been shown to reduce the age-related decline in FEV1, significantly in middle-aged smokers with mild airways obstruction, and also lead to a decrease in cardiovascular and lung cancer mortality. Smokers should be told to stop and an agreed target date set. Nicotine replacement therapy (NRT) or bupropion is given, unless contraindicated, in addition to a support programme to improve the chances of success.

Drug therapy

This is used both for the short-term management of exacerbations and for the long-term relief of symptoms in patients with an FEV1 < 80% predicted.

Bronchodilator therapy

Inhaler therapy remains the mainstay of treatment, despite the fact that COPD is characterized by irreversible airway obstruction. It causes relaxation of the smooth muscle and thus decreases airway resistance. Patients with mild COPD feel less breathless.

Side-effects include fine tremor, nervous tension, tachycardia, arrhythmias and hypokalaemia.

Side-effects include dry mouth, nausea, constipation, bladder outlet obstruction, exacerbation of acute-angle glaucoma and headache.

In mild disease short-acting β2 agonists or short-acting antimuscarinic bronchodilators should be prescribed as required. Their effects are additive and once airflow becomes more severe a regular antimuscarinic can be added to a β agonist. Some patients prefer to use just one combined inhaler ipratropium bromide 20 mcg and salbutamol 100 mcg/metered dose 2 puffs 4 times a day.

Patients who remain symptomatic despite being treated with a combination of two short-acting bronchodilators or patients who have two or more exacerbations a year should be prescribed a long-acting bronchodilator and an inhaled corticosteroid should be added (see below).

Objective evidence of improvement in peak flow or FEV1 may be small and the decision on whether to continue or stop therapy should be based on the patient’s reported symptoms.

Corticosteroids

Corticosteroids are given to patients in the community with increasing shortness of breath that interferes with daily activities. Inhaled corticosteroids are usually reserved for stable COPD, but if already prescribed, should be continued throughout exacerbations.

There are many side-effects associated with corticosteroids (see Box 15.2, p. 585). Inhaled steroids cause considerably fewer systemic side-effects, although at high doses adverse effects have been reported.

Oxygen therapy

The following patients should be assessed for oxygen therapy:

Patients fulfil the criteria for LTOT when they have:

Guidelines for domiciliary oxygen are shown in Box 13.2.

Patients requiring LTOT will need an oxygen concentrator and education regarding its use. They should use the oxygen for at least 15 hours per day or, if possible, 20 hours per day. Once established, they should be reviewed at least once a year by a practitioner familiar with LTOT. They should be warned about the risks of explosion and fire if they continue to smoke. Short-burst oxygen should be reserved for patients with episodes of severe breathlessness that is not relieved by other treatment.

An oxygen alert card stating the oxygen saturation should be given to all patients who have had hypercapnic respiratory failure.

Other agents

Acute exacerbations of COPD (type II respiratory failure)

An acute exacerbation is defined as ‘a sustained worsening of the patient’s symptoms from his or her usual stable state that is beyond normal day-to-day variations, and is acute in onset’.

Exacerbations of COPD are among the commonest acute respiratory problems presenting to primary or secondary care.

Treatment

The treatment of respiratory failure in COPD is shown in Fig. 13.1. General care includes prophylaxis against deep vein thrombosis, optimizing fluid status and ensuring adequate nutrition.

Bronchodilators (p. 478). There is no benefit in delivering bronchodilators via a nebulizer over an inhaler in acute exacerbations of COPD. Bronchodilators are, however, given via a nebulizer with a face mask or mouth piece delivering higher doses if patients are too breathless to coordinate the use of an inhaler/spacer. If the patient is hypercapnic, the nebulizer should be driven with air and not oxygen. Oxygen can be given at the same time via nasal cannulae.
Inhaled β2 short-acting adrenergic agonists (p. 478). The frequency and dose of inhaled β2-agonists can be increased in an acute exacerbation. They reach peak activity between 10 and 30 mins, and remain effective for about 4–6 hours. Salbutamol (via inhaler or nebulizer) is the most commonly used. Nebulizers are given at a dose of 2.5–5 mg, usually 4 times daily, although this can be increased provided side-effects are tolerated. Currently, there is no evidence to support the use of IV β2-agonists in acute exacerbations of COPD.
Antibiotics (p. 482). There is some evidence for a small but significant benefit with antibiotics in acute exacerbations of COPD, especially in those with more severe disease. The use of antibiotics is recommended in patients with a history of increased purulence or production of sputum or in those with consolidation on CXR or clinical signs of pneumonia. Initially, treatment is empirical, with an aminopenicillin, a macrolide or a tetracycline, and then changed when culture results and sensitivities become available. Antibiotic use should be guided by local policy. Commonly used antibiotics include amoxicillin 250–500 mg 3 times daily (15% of Haemophilus strains may be resistant), doxycycline 200 mg then 100 mg daily, or erythromycin 250–500 mg every 6 hours or 0.5–1 g every 12 hours. Ampicillin can be used instead of amoxicillin.
Methylxanthines. The use of methylxanthines such as theophylline (p. 501) remains controversial, as there is currently no clear evidence of benefit in acute exacerbations of COPD. IV theophylline should only be used in patients refractory to nebulized bronchodilators, and levels should be monitored within 24 hours of treatment and regularly after this period. Patients already taking oral methylxanthines should continue on this medication during an exacerbation and should not receive additional IV methylxanthines. IV methylxanthines are usually prescribed as aminophylline loading dose 5 mg/kg (250–500 mg) over at least 20 mins, followed by 0.5 mg/kg/hour over 24 hours adjusted according to plasma levels. Patients should be closely monitored throughout.

Obstructive sleep apnoea/hypopnoea syndrome

Factors predisposing to OSAH include increasing age, male gender, obesity, sedative drugs, smoking and alcohol consumption.

Diagnosis

Treatment

Treatment depends on the severity of disease, underlying medical conditions and patient compliance. Management should consist firstly of correction of treatable and potentially reversible factors.

Non-surgical interventions

Cystic fibrosis

Cystic fibrosis (CF) is a common recessively inherited disease with an incidence of 1 in 2500 and a calculated carrier frequency of 1 in 25 in the UK. It is more common in the Caucasian population.

Clinical features