Respiratory medicine

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chapter 41 Respiratory medicine

INTRODUCTION AND OVERVIEW

The human respiratory system is complex and finely tuned. Fortunately, two factors are of enormous benefit to us. First, there is a large reserve of function, greater than many of us are ever going to call upon; and secondly, the respiratory system can tolerate quite a degree of insult before symptoms appear. The predominant symptoms of respiratory problems that present to GPs are breathlessness, cough, sputum, wheeze and chest pain.

Diagnosis is the important first step in medical practice, and the classic method of adequate history, appropriate physical examination, thinking about the clinical problem and then considering special investigations will clarify most situations.

IMPORTANT CONDITIONS

The four diagnoses that are most prominent and/or important in general practice are:

• asthma
• chronic obstructive pulmonary disease (COPD)
• lung cancer
• infections.

The Bettering the Evaluation And Care of Health (BEACH) data show the distribution of respiratory problems managed in general practice (Table 41.1).1

TABLE 41.1 Important respiratory conditions managed in general practice

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Infections of particular importance are best considered as:

• bacterial—community-acquired pneumonia
• viral—viral upper respiratory tract infection (URTI)
• other—including opportunistic infections (PCP) and tuberculosis (TB).

ASTHMA

BACKGROUND AND PREVALENCE

It is estimated that worldwide as many as 300 million people of all ages have currently diagnosed asthma. The prevalence of asthma in Australia is quite high, with one in six children (14–16%) and one in nine adults (10–12%) having the disease.2 There is variation between countries in the incidence of asthma (this is detailed in the document Global burden of asthma (see Resources list at the end of this chapter)).

The condition we call asthma involves a number of pathological processes including inflammation, smooth muscle spasm and increased airways secretions. In essence it is a chronic inflammatory disorder affecting the airways. Many types of cells play a role in this inflammatory process, including mast cells, eosinophils, T-lymphocytes, macrophages, neutrophils and epithelial cells. Individuals who experience asthma generally have a genetic susceptibility that can also be affected by lifestyle and environmental factors. Airway inflammation causes recurrent episodes of asthma associated with the symptoms of wheezing, shortness of breath, chest tightness, and also coughing, most commonly at night or in the early morning or in response to exercise. These episodes of wheezing and dyspnoea brought on by widespread airflow obstruction will reverse spontaneously or with treatment.2 In those disposed to airway hypersensitivity, the inflammation is usually triggered by environmental factors such as allergens, irritants and temperature change. Psychological and emotional factors can also trigger or aggravate episodes of asthma.

AETIOLOGY

Asthma manifests as a combination of atopy, bronchial hyper-reactivity and IgE- and non-IgE-mediated acute and chronic immune responses. Most authorities accept that it occurs as a result of the action of a variety of environmental stimuli on genetically predisposed people.3

PATHOLOGY

The description of asthma given above, based on the National Asthma Council of Australia’s definition, covers the pathology of asthma quite succinctly.

DIAGNOSTIC APPROACH

It is important that a careful clinical history is taken (see below). An examination is done (in order to assist in excluding other differential diagnoses) and objective lung function testing, preferably spirometry, is performed.

HISTORY

As asthma is most often an intermittent disease, the history is of symptoms that wax and wane—there are episodes of symptoms. The most sensitive symptom of uncontrolled or destabilising asthma is awakening during the night with asthma symptoms such as chest tightness, breathlessness and wheeze. If the patient (or witness) reports hearing a wheeze with expiration, this is very suggestive, but not diagnostic, of asthma. Other information that supports the diagnosis of asthma include:

• a personal history of previous recurrent episodes of asthma (or symptoms suggestive of asthma if the diagnosis has not yet been made)
• normal respiratory and functional performance in the intervals between episodes
• a personal history of atopic (especially flexoral) eczema
• a family history of asthma.

If there are clearly identifiable triggers that precipitate episodes of cough, breathlessness or wheeze, this is strongly suggestive of asthma. The more common asthma triggers are viral URTI, change in ambient air temperature, house dust mite and exercise.

EXAMINATION

Physical examination is, on most occasions, normal unless the patient is in the midst of an asthma attack (i.e. an episode of bronchospasm). In the past, the chronic untreated asthma sufferer sometimes had a deformed thoracic area with a barrel chest and spreading of the ribs, but this is now only seen, in developed countries, in historical textbooks of medicine.

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FIGURE 41.1 Airway affected by asthma (right); a healthy airway is shown on the left

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FIGURE 41.2 Mucus hypersecretion in asthma: A The airway lumen is plugged with mucus released from the submucosal gland via a gland duct; B (higher magnification) Mucus can be seen streaming from the luminal tips of the goblet cells into the lumen

INVESTIGATIONS

• In the consulting room—spirometry is the ‘gold standard’ for objective lung function testing.
• Away from the surgery—encouraging self-monitoring by the measurement of peak expiratory flow rate (PEFR) is worthwhile. This is particularly important where the history suggests occupational or hobby-associated asthma. PEFR is also an important way for some patients to self-monitor their asthma, so they know when control of their asthma is slipping.
• Pathology—if one is looking for an allergic cause of asthma, sometimes radioallergosorbent testing (RAST) or skin prick testing is useful in helping to identify specific triggers. However, careful history taking will often narrow the allergens to a manageable number so that specific investigations are not needed.
• Special tests—these are rarely needed unless one is attempting to exclude differential diagnoses that have not been excluded by clinical methods.

INTEGRATED MANAGEMENT

Prevention

The ‘hygiene hypothesis’4 is a theory, still being debated,5 that links an increased risk of atopic disease with reduced microbial exposure from a variety of sources during childhood. Epidemiological studies are providing increasingly strong evidence that protection from atopic disorders including asthma is afforded by early-life exposure to environmental microbes. For example, children who are raised on farms, who drink unpasteurised milk, have more older siblings or attend day care at an earlier age are protected to some extent against asthma. This may explain to some extent the ‘asthma epidemic that has been occurring, especially in developed nations, over the past several decades’.6

If the ‘hygiene hypothesis’ is correct, letting children ‘get down and dirty’ may become a preventive activity!

Respiratory hygiene and minimising spread of infection is important in preventing exacerbations. Ensure routine immunisation against Haemophilus influenzae, seasonal influenza and pertussis (whooping cough).

Active surveillance

If we look back to when there were no effective treatments for asthma, the consequences of providing no active intervention are well described. Although patients can sometimes learn to ride out mild asthma attacks using self-help techniques such as breathing exercises, thereby reducing the need for reliever medication, doing nothing for moderate to severe asthma, or not taking preventer medications where asthma episodes are frequent, would not be considered a valid option. A worst-case scenario is that it is life-threatening. This is especially so for those with a history of brittle asthma and severe attacks.

Self-help

Many self-help strategies or home remedies are suggested but robust evidence of their efficacy is often lacking. Self-help strategies or home remedies that have been subjected to scrutiny and are listed in the medical literature are described below.

Tobacco avoidance

Cease smoking and avoid exposure to other people’s smoke. Exposure to cigarette smoke can trigger asthma attacks, increase the frequency of asthma attacks, cause the need for higher doses of preventer and reliever medication, increase the need for asthma medication and reduce lung function. Children exposed to cigarette smoke are more likely to develop asthma and have more severe symptoms and more frequent attacks.

House dust mite control

The major allergen in house dust comes from mites. Although methods of reducing dust mite exposure, such as adequate ventilation, keeping a dust-free environment and having regular fresh bed linen, are intended to reduce asthma symptoms, these methods have not been as successful as expected.7

Ion generator

Although marketed for use in homes to reduce asthma by removing dust and smoke particles, and although some studies show that ion generators can alter airways function, ‘the few studies which have been conducted in the homes of people with asthma, demonstrate no significant benefit in improving lung function or symptoms’.8

Pets

Some people with asthma are allergic to their own and others’ pets. The solution for many is the removal of the pets, to reduce exposure to the allergens in their hair and skin, but other methods such as pet washing, sprays and air filtration units can help reduce the amount of allergen in the air and on the floor of the home. The evidence is not at present conclusive.9

Caffeine

Caffeine (a methylxanthine drug) is related to the theophyllines that used to be commonly prescribed for asthma. These have an effect on the airway musculature. Caffeine is commonly found in coffee, tea, cola drinks and cocoa, and it has been found that even small amounts of caffeine can improve lung function for up to 4 hours, but for some the amount required to improve symptoms may be offset by the other side effects of caffeine.10

Fish oil

Many people with asthma who change their diets to include more fish oil do not improve their asthma,11 but other evidence has suggested that others do. There has been some work published on taking fish oil supplements (rather than just increasing fish in the diet). In one study,12 some benefit was shown in people with predominately exercise-induced bronchospasm (EIB) but the authors have given the guarded advice that ‘fish oil supplementation may represent a potentially beneficial non-pharmacological intervention in asthmatic patients with EIB’.

Vitamin C, vitamin E and beta-carotenes

There is a great deal of research under way into whether specific dietary supplementation is of benefit in asthma. Consensus on the importance of eating enough fresh fruit is yet to emerge, but one review found that:

Longitudinal data support the hypothesis that fresh fruit consumption has a beneficial effect on the lung. Among children, consumption of fresh fruit, particularly fruit high in Vitamin C, has been related to a lower prevalence of asthma symptoms and higher lung function.13

The message is therefore that a healthy diet is far more likely to be beneficial in asthma than supplements, particularly in the presence of a poor diet.13

Tartrazine exclusion

Tartrazine is one of the most commonly used food and medication additives or colourants. The evidence that tartrazine makes asthma worse, or that avoiding it makes asthma patients better, is questionable.14

Pharmacological

The cornerstone of asthma management is the use of inhaled corticosteroids. The greatest challenge is in deciding when they are required and in what dose. The recommendation of the National Asthma Council Australia is summarised in Figure 41.3.2a

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FIGURE 41.3 Management of mild, moderate and severe persistent asthma. BDP-HFA: beclomethasone dipropionate; ICS: inhaled corticosteroid; LABA: long-acting beta-2 agonist; LTRA: leukotriene receptor antagonist

(from NACA 20062)

Surgical

There has been some very early work on destroying the muscle layer in the airways as a means of minimising asthma symptoms, but this is still experimental.

Breathing exercises

The way in which ‘breathing exercise’ or ‘re-training’ is understood varies depending on the form of the therapy, the therapist providing the therapy and the cultural background of the person having the therapy. Some of the earlier studies of breathing exercises were small or had methodological flaws, but more recent studies demonstrate a trend for improvement.15 Evidence on breathing exercises, including yoga-based breathing exercises16, in asthma suggests that they can provide objective and subjective benefit and can be useful in reducing the need for reliever and preventer use.17 The Buteyko method is also widely used in asthma. Evidence suggests that it provides subjective benefit, although results indicating whether it also provides objective benefit have been inconsistent. It is best to learn breathing exercises from health professionals trained in their use.

Complementary therapies

Dietary supplements

There has been much interest in whether specific dietary supplementation can influence the clinical course of asthma. Many entities and results have been examined but the authors of the studies are careful in making claims. One study showed that the lipid extract of New Zealand green-lipped mussel had a beneficial effect in patients with atopic asthma.18

Adolescents with a less nutritious diet, with a lower intake of antioxidants and anti-inflammatory micronutrients, have poorer pulmonary function and increased respiratory symptoms, especially among smokers. The likely explanation is that these nutrients promote respiratory health and lessen the effects of oxidative stress.19 Dietary supplementation or adequate intake of lycopene and foods rich in vitamin A may also be beneficial in asthma.20

Acupuncture

The evidence is not clear and consistent enough to make firm recommendations about the value of acupuncture in asthma.21 It may be that some forms of acupuncture are more beneficial than others, or that acupuncture is beneficial for some variants of asthma but not others.

Alexander Technique

The Alexander Technique is a form of movement-based physical therapy. It is commonly used to correct posture and bring the body into natural alignment, and also as an aid to relaxation and greater body awareness. Although there are some positive findings, a review of trials found that there was not enough evidence to show a benefit of the Alexander Technique in reducing the need to use medication for asthma.22

Herbal treatments

Evidence from 27 trials covering 21 different herbal treatments for both adults and children, and from both inpatient and outpatient settings, was inconclusive generally because of methodological limitations of the trials. Although further trials of high quality are needed to assess the use of herbal treatments in asthma, there is enough positive preliminary evidence to suggest that some of these compounds will prove to be of benefit.23

Homeopathy

Different types of homeopathy are used for asthma, such as classical homeopathy (tailored to an individual’s bodily and psychological constitution and their symptoms) or isopathy (e.g. using a dilution of an agent that causes an allergy, such as pollen). In the existing studies on homeopathy and asthma, the type of homeopathy used varies and study designs are sometimes poor. Consequently, there is no strong evidence that homeopathy is effective for asthma.24

Speleotherapy

Speleotherapy, or staying in an underground environment such as a cave or mine, is believed by some to be of benefit for people with asthma. If benefits are there, it is believed that they come from air quality, underground climate (cool and humid), air pressure or radiation. Evidence is more anecdotal than derived from high-quality randomised controlled trials.25

ONGOING REVIEW AND/OR MONITORING

Asthma is a chronic disease and, as such, is worthy of regular planned medical review. However, it is the experience of many clinicians that people with asthma tend to view their asthma as an intermittent disease and so take medications and seek treatment only when they are particularly troubled by symptoms.

IMPORTANT PITFALLS

Making an accurate diagnosis of asthma can be particularly difficult in the paediatric age group, when the history and response to empirical treatment are the only guides. In the older patient, it is important to differentiate asthma from COPD (see below) but, at the same time, to be aware that some people have a mixed picture. If there is significant reversibility on spirometry (post-bronchodilator FEV1 increases by 200 mL and 12%), treat as asthma.

PROGNOSIS

More children than adults manifest asthma and so the assumption is that, as a problem, asthma ‘weakens’ with age. It is probably better to accept the view of the National Asthma Council Australia that:2

education, together with self-monitoring, appropriate drug therapy, regular medical review and a written asthma action plan, reduces morbidity and mortality.

Most people with asthma lead normal lives and can participate competitively in sport.

PATIENT EDUCATION

There is a wealth of useful material available at the National Asthma Council Australia website (see Resources list).

CHRONIC OBSTRUCTIVE PULMONARY DISEASE

BACKGROUND AND PREVALENCE

Chronic obstructive pulmonary disease (COPD) is a major cause of disability, hospital admission and premature death. It is commonly associated with other diseases including heart disease, lung cancer, stroke, pneumonia and depression.26 In a community-based survey that included lung function testing, doctor-diagnosed chronic bronchitis or emphysema was reported by 4.3% of the population. When clinical diagnosis is combined with complex lung function testing and an FEV1/FVC of less than 75%, around 12% of the population have some evidence of emphysema.27 This figure will be considerably higher in countries where anti-smoking legislation and campaigns are less prominent.

Definition

According to the Australian and New Zealand guidelines on COPD,26 COPD is:

characterised by airway inflammation and airflow limitation that is not fully reversible. It is a progressive, disabling disease with serious complications and exacerbations that are major burdens for healthcare systems.

AETIOLOGY

COPD is really a group of diseases that are clustered together—the more common sub-types are emphysema, chronic bronchitis and fixed airflow obstruction due to asthma.

COPD is the end result of chronic insults to the lungs. 70% of COPD is related to cigarette smoking28 but it can result from any particulate matter insult (in low-income countries this is often the indoor burning of biomass for cooking and heating) or air pollution.

PATHOLOGY

As the term ‘COPD’ covers a number of discrete entities (emphysema, chronic bronchitis, fixed airflow obstruction with chronic asthma), the pathology of each is different and is beyond the scope of this chapter.

DIAGNOSTIC APPROACH

The tried and true pattern of adequate history, appropriate physical examination, thinking about the clinical problem and then considering special investigations will clarify most situations.

HISTORY

The cardinal symptoms are:

• breathlessness
• cough
• sputum.

How these symptoms combine gives an indication of the underlying cause of the COPD. There is usually a past or present history of cigarette smoking.

• emphysema—predominant breathlessness, especially on (often minimal) exertion
• chronic bronchitis—the formal definition is: ‘the production of sputum on most days for 3 months over 2 successive years’. In milder cases this is often discounted by the patient as being a ‘smoker’s cough’.

EXAMINATION

The physical examination gives an indication of the predominant pathology:

• emphysema—signs of hyperinflation (barrel-chested with increase in anterioposterior (AP) diameter, pursed-lip breathing, use of accessory muscles of respiration)
• chronic bronchitis—prolonged expiratory phase of respiration.

INVESTIGATIONS

• Consulting room—spirometry and pulse oximetry
• Pathology—FBC demonstrating polycythaemia
• Special tests—chest X-ray will give a suggestion of hyperinflation, flattening of the diaphragm. CT scanning, especially high-resolution CT, gives a view of the lung parenchyma and is most helpful for diagnosing emphysema and bronchiectasis.

INTEGRATIVE MANAGEMENT

One of the problems with COPD is the acute exacerbations that occur. They are diagnosed when there is an increase in any (or all) of the common COPD symptoms, especially increased shortness of breath, increase in cough, and/or increase in amount or purulence of sputum. It seems that the earlier symptoms of an exacerbation are increase in dyspnoea and cough, and the increase in purulence of the sputum comes later.

Exacerbations cause both physical and psychological distress to the patient and are a substantial burden on the health system.

Of exacerbations, approximately 80% are infectious (40–50% bacterial, 30–40% viral and 5–10% atypical) and 20% are non-infectious (due to either an increase in the environmental load of irritants or non-compliance with management strategies including medications). The viral exacerbations correlate with viral epidemics among children. COPD sufferers who are still smoking get more viral infections than non-smokers and so get more exacerbations.

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FIGURE 41.4 Clinical features of COPD

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FIGURE 41.5 Spirometry tests

Prevention

As COPD in industrialised countries is commonly due to cigarette smoking, all healthcare providers should be aware of the need to identify and then try to assist smoking cessation in those who smoke cigarettes.

It is worth noting that, in terms of particulate insult to the lungs, one marijuana ‘bong’ is considered to be equivalent to five cigarettes and so, in those who use marijuana, this needs to be added in to the particulate load when calculating ‘pack years’.

At present the only thing known to reduce the rate of decline in lung function in COPD due to cigarette smoking is to encourage the patient to stop smoking.

In countries where the indoor burning of biomass fuels is used for cooking and heating, enabling extraction of the smoke and particulate matter with chimneys and flues should be encouraged, in order to reduce the incidence of COPD.

Respiratory hygiene and minimising spread of infection is important. Ensure routine immunisation against Haemophilus influenzae, seasonal influenza and pertussis (whooping cough).

Self-help

As most smokers quit without any particular medical intervention, simply identifying and advising current cigarette smokers to quit is of benefit (see Ch 62, Substance misuse).

Pharmacological

The stages of COPD are defined using spirometry. The definition depends on having a post-bronchodilator FEV1/FVC ratio ≤ 0.7. The severity of the COPD is graded on the degree of airflow obstruction compared with the population (in Fig 41.6 this is stated as ‘% predicted’). Therefore, mild COPD is a FEV1/FVC ratio ≤ 0.7 with FEV1 ≥ 80% predicted for a person of the same age, gender, height and ethnicity. Modern electronic spirometers calculate the ‘% predicted’ for the practitioner.

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FIGURE 41.6 Therapy at each stage of COPD

(Source: Global Initiative for Chronic Obstructive Lung Disease www.goldcopd.org)

Surgical

Lung volume reduction surgery is a major operation sometimes offered to people with severe emphysema. The assessment of patients being considered for operation is complex and is usually reserved for specialised multidisciplinary units. There is significant perioperative mortality with this surgery. The outcomes of surgery suggest that, in patients who survive up to 3 months post surgery, there is significantly better health status and lung function in those who have the surgery than in those who have the usual medical care alone.29

Paramedical

Pulmonary rehabilitation programs have been shown to improve the physical functioning, symptoms and mental health of people with COPD. It reduces hospitalisations and has been shown to be cost effective.

Complementary therapies

Herbal medicines

The effectiveness of herbal medicines for treating COPD is not well established and so more high-quality trials are needed.30

Nutritional supplementation

Low body weight is common in people with COPD, which impairs heart and lung function enough to reduce the person’s ability to exercise as an aid to recovery. A degree of malnutrition is common in people with COPD and can signify a lack of self-care or other comorbidity, but it is unclear whether this is the cause of their deterioration, or just a sign of disease progression. It is questionable whether nutritional supplementation makes a significant difference to the course of COPD itself, but it will nevertheless be useful for general wellbeing.31

With emphysema in particular, the work of breathing is increased so much that the sufferer cannot take in sufficient calories to avoid weight and lean muscle loss. Pulmonary rehabilitation programs often attend to this but these people will often benefit from a review by a dietician, and consideration of protein and caloric supplementation and of whether multivitamin supplements are necessary.

ONGOING REVIEW AND/OR MONITORING

Unfortunately, COPD is a progressive disease. The rate of progression is affected by whether:

• the lung irritation is removed (be it cigarette smoking or exposure to wood smoke from indoor cooking and heating)
• the patient has acute infective exacerbations of their disease. In addition, these people often have significant comorbidities such as cardiovascular disease, due to the same factor—cigarette smoking.

Because of these matters, these patients are often frequent attenders in the primary healthcare system. Because of this they are seen often but only occasionally have a formal review or ongoing monitoring of their COPD—the healthcare system is often reacting to an acute problem rather than planning ongoing care of their chronic disease.

A planned review visit for COPD should include:

• review of symptoms
• enquiry regarding smoking status
• review of medication and inhaler device use
• lung function testing
• immunisation status
• review of the written COPD action plan for exacerbations.

IMPORTANT PITFALLS

Asthma and COPD share some features and treatment modalities. It is important to attempt to differentiate between the two, as the finer points of management and the prognoses of the two diseases are different.

PROGNOSIS

COPD is a relentlessly progressive disease and the best that can be hoped for is to slow the rate of progression and minimise symptoms. It is possible to predict the longer-term progression of COPD by using the BODE index.32 The BODE parameters, measurable in general practice, are:

• B—body mass index
• O—degree of obstruction
• D—level of dyspnoea
• E—exercise distance.

The prognosis of COPD depends on disease severity and, as earlier diagnosis and smoking cessation influence this, all healthcare providers should aim to assess and provide advice on smoking to the people they see in consultation.

PATIENT EDUCATION

A wealth of patient information is available (see the Resources list).

LUNG CANCER

According to the World Health Organization, cancer is a leading cause of death worldwide: it accounted for 7.9 million deaths (around 13% of all deaths) in 2007. Most cancer deaths are caused by cancer of the lung, stomach, liver, colon and breast cancer. Tobacco use is the single most important risk factor for cancer.33

In a general practice caring for approximately 10,000 patients, there may be four new lung cancer diagnoses per year.34

Small-cell lung cancer has usually spread into the bloodstream by the time it is diagnosed. However, it is sensitive to both chemotherapy and radiotherapy, which are usually administered as the first line of treatment, rather than surgery.

Non-small-cell lung cancer represents approximately 80% of lung cancers.35 Non-small-cell lung cancers are broadly divided by their main cell type into squamous cell, adenocarcinoma and large cell. If detected early it can initially be managed with local treatments such as surgery and/or radiotherapy.

AETIOLOGY

Insults to the respiratory tract are the most common cause of cancer. The most common insult to the lung is that caused by cigarette smoking, but other risk factors include:

• increasing age
• exposure to lung irritants—asbestos; occupational dusts and chemicals, most notably silica, cadmium, arsenic, nickel, chromium and beryllium.

DIAGNOSTIC APPROACH

Adequate clinical history, appropriate physical examination, thinking about the clinical problem and then considering special investigations will clarify most situations.

HISTORY

Chronic cough is probably the most common symptom of lung cancer. Unfortunately, those with COPD also have a chronic cough and, as there is a shared causative factor (cigarette smoking), the doctor needs to consider lung cancer developing in someone with COPD. Haemoptysis and undesired weight loss can alert the clinician to the presence of a malignancy. In a person who has an infection such as pneumonia in the upper zones, be aware that there may be an obstructing lesion.

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FIGURE 41.7 Chest X-ray of lung cancer: the ‘golden S’ sign—with a mass near the hilum, the inferior margin of the upper lobe takes on an S shape as it goes around the mass

EXAMINATION

There may be clinical evidence of COPD or regional lymphadenopathy.

INVESTIGATIONS

• In the consulting room, spirometry may demonstrate COPD (which often has the same aetiology as lung cancer).
• Pathology:

• sputum cytology—has a low sensitivity but the specimen must be properly collected, not just saliva
• special tests—chest X-ray and CT scanning may demonstrate the mass, and bronchoscopy is recommended to get tissue for pathological examination.

INTEGRATIVE MANAGEMENT

Prevention

As cigarette smoking and working with dusts and chemicals are known to cause lung cancer, preventive strategies based on encouraging and supporting smoking cessation and mandating protective programs for those who are exposed to noxious dusts and chemicals are critical in preventing lung cancers.

Surveillance

Surveillance alone is not a valid option unless the malignancy is so far advanced that palliation is all that can be offered (see Ch 39, Palliative medicine).

Self-help

Smoking cessation, even after diagnosis, may improve the efficacy of the various treatment modalities.

Pharmacological

Each type of lung cancer has a preferred treatment and this is specialised work. The oncology team will determine which regimen is most likely to have maximal effect.

Surgical

Surgical treatment of lung cancer depends on the type of lung cancer and its anatomical distribution. Again, these decisions need to be made by experts in this specialised area.

Complementary therapies

There are many therapies that can make the person with cancer feel better—massage, relaxation and meditation are examples (see Ch 24, Cancer).

IMPORTANT PITFALLS

Making a diagnosis is important, and appropriate investigation of patients at risk of lung cancer is crucial.

PROGNOSIS

Small-cell lung cancer

Small-cell lung cancer is an aggressive disease. The median survival time for limited disease is 18–24 months, with only 25% of patients alive after 5 years. More extensive disease is treated with chemotherapy and, even with this treatment, median survival is in the order of 12 months, with only 10% of patients surviving for 2 years.36

Non-small-cell lung cancer

Of patients with operable non-small-cell lung cancers that have not metastasised, up to 80% can expect to be alive at 5 years. For tumours that have spread to the lymph nodes, the 5-year survival rate drops to 25–30%. For patients with more widespread metastatic spread but who are still fit enough to receive chemotherapy, the 5-year survival rate is in the order of 15–35%.37

PATIENT EDUCATION

Providing education about not taking up smoking or cessation if it has already commenced is a crucial role for the GP.

INFECTIONS

Respiratory infections can be classified as viral, bacterial, atypical or tuberculosis.

VIRAL UPPER RESPIRATORY TRACT INFECTIONS

The prevalence of upper respiratory tract infections (URTI) is shown in Table 41.2.

TABLE 41.2 Respiratory problems managed in primary care

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Aetiology

General practitioners can become ‘local’ epidemiologists in that they often become aware quite quickly that ‘something is around’. The common cold, coryza or URTI presents with a constellation of symptoms familiar to all. One needs to differentiate the common URTI from a ‘true’ influenza. With an influenza infection there are more systemic symptoms, with a significant fever (> 38.5°C), myalgia, arthralgia and headache.

Diagnosis

The common cold is so familiar to GPs that diagnosis is not a problem.

Treatment

• Self-help—usually common, simple, symptomatic measures are recommended (paracetamol, bed rest and oral fluids).

Most of the respiratory infections seen in primary care are self-limiting viral URTIs. Even though it is almost impossible for people to avoid coming into contact with these viruses, it is important to keep the defences in the best possible condition and so minimise the number of URTIs contracted. How to maintain the healthiest possible immune system is discussed elsewhere (see Ch 32, Principles of the immune system).

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FIGURE 41.8 Pharyngitis

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FIGURE 41.9 Bacterial tonsillitis: A Diffuse tonsillar and pharyngeal erythema can be produced by a variety of pathogens; B Intense erythema with acute tonsillar enlargement and palatal petechiae is highly suggestive of group A beta-streptococcal infection; C Exudative tonsillitis is most commonly seen with either group A streptococcal or Epstein-Barr virus infection

• Steam inhalation—although this has been used for generations, evidence as to whether it improves nasal congestion for a person with a cold is insufficient. Some studies found that inhaling steam helped symptoms, but others did not; and there were some adverse effects, such as discomfort or irritation of the nose or lips.37
• Pharmacological—for the simple URTI, paracetamol is usually all that is required.

Complementary therapies

• Echinacea—this has been widely used for preventing and treating the common cold. Echinacea preparations available on the market differ greatly, as different species, plant parts (e.g. herb, root or both) and manufacturing methods (drying, alcoholic extraction or pressing) are used. A review of 16 controlled clinical trials on different Echinacea preparations for preventing and treating common colds suggests that the evidence that it can help to shorten the duration of the cold and related symptoms is stronger than evidence that it can prevent colds.38
• Andrographis paniculata—has been shown to have antiviral properties and to shorten the duration and severity of symptoms of the common cold.39 Typical dose: 500 mg t.d.s.
• Astragalus—has antiviral properties and stimulates the immune system, suggesting that it may be effective at preventing colds. Standardised extract: 250–500 mg, 3–4 times a day.
• Vitamin C—a 2007 Cochrane review40 found that vitamin C reduced the duration and severity of common cold symptoms slightly. However, with regard to prevention, ‘The failure of vitamin C supplementation to reduce the incidence of colds in the normal population indicates that routine mega-dose prophylaxis is not rationally justified for community use. But evidence suggests that it could be justified in people exposed to brief periods of severe physical exercise or cold environments’.
• Zinc—deficiency should be corrected. Clinical trial data support the value of zinc in reducing the duration and severity of symptoms of the common cold when administered within 24 hours of the onset of common cold symptoms. However, overall data studying the use of various forms of zinc for treatment of colds are inconclusive.41
• Homoeopathic oscillococcinum—research suggests that this does not seem to prevent influenza but it may shorten the duration of the illness.42

Ongoing review and/or monitoring

Most URTIs are self-limiting. It is prudent to warn the patient to contact their GP if the URTI does not follow the expected pattern, as there is always the possibility of bacterial super-infection or exacerbation of an underlying comorbidity.

Prognosis is excellent unless there are significant comorbidities that can render the patient vulnerable to complications. A common cause of destabilisation of asthma is a viral URTI. Many acute exacerbations of COPD are precipitated by viral infections. If the patient is immunocompromised (e.g. HIV/AIDS, malignancy and iatrogenic immunosuppression), an URTI is capable of causing many problems.

Patient education

Rest, simple symptomatic treatments, cough hygiene and some degree of ‘isolation’ to minimise spread of the virus are important messages to give to the patient.

TUBERCULOSIS

Tuberculosis (TB) remains a global problem. In 2008, there were an estimated 9.4 million incident cases worldwide—this is equivalent to 139 cases per 100,000 population. Most of the estimated number of cases in 2008 occurred in Asia (55%) and Africa (30%).43

Tuberculosis is a notifiable disease, as it is quite contagious. As such, cases should be notified promptly to the relevant public health authorities. Both the World Health Organization and the International Union against Tuberculosis and Lung Disease run international programs for TB prevention and management.

The symptoms of TB are vague (cough, sputum, breathlessness, haemoptysis, weight loss, fever, malaise and anorexia).44 Think of it in the person with a chronic cough, particularly if it is productive. There are also extra-pulmonary manifestations of TB, including lymph nodes, genitourinary tract, pleura, pericardium, bones and joints, meninges, eye, skin, adrenal glands and gut.

Immigrant populations from areas of high background incidence—Indian subcontinent, Africa, South-East Asia and the former Eastern Bloc countries—are a high-risk group as reactivation can occur in the presence of immunosuppression.

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FIGURE 41.10 Chest X-ray of TB

Tuberculosis should also be considered in those at risk of a reactivation of quiescent TB—the immunosuppressed. Consider the large number of people in your practice who are on immunosuppressive therapy (e.g. post-transplant patients, rheumatoid disease, systemic lupus erythematosus (SLE), polymyalgia rheumatica, recurrent rescue prednisolone for acute exacerbations of COPD). Also consider diseases that are inherently immunosuppressive—HIV/AIDS and many cancers. There are a large number of people in these categories and this heightens their risk of reactivation of TB.

Diagnosis

Diagnosis is made on the basis of the chest X-ray and sputum microscopy and culture.44 Polymerase chain reaction (PCR) rapid diagnostic tests are available in some places but the more important thing is that the possibility of TB is considered and acted upon.

A Mantoux test may be a useful guide.

Biopsy of accessible extra-pulmonary lesions such as lymph nodes may be performed.

Consider HIV testing.

Treatment

According to Australian Therapeutic Guidelines: Respiratory,45 patients with TB should:

• be managed only by specialists with appropriate training and experience
• be notified promptly to the relevant state public health authorities
• have contact tracing performed by public health nurses liaising closely with the treating doctors.

Because of concerns about drug resistance, bacterial confirmation of the diagnosis, and drug susceptibility testing, should be strenuously pursued.

Adequate adherence to anti-tuberculous therapy is vital in order to:

• achieve a satisfactory treatment outcome
• reduce the risk of transmission to contacts
• reduce the risk of relapse
• prevent the emergence of drug resistance.

Measures to improve adherence include:

• comprehensive patient and family education (in the form of verbal and written information)
• close and consistent follow-up
• provision of directly observed therapy (DOT).

The most common drugs used to treat TB are isoniazid, rifampin, pyrazinamide, ethambutol and streptomycin, usually in combinations of four. If problems with supply of anti-tuberculous drugs arise, the state health department should be contacted.

• Probiotics will be a necessary adjunct.
• Avoid alcohol during treatment because of potential hepatotoxicity.
• Avoid tobacco smoke.
• There are significant public health issues with TB and so expert assistance is usually required when the diagnosis has been made.

Nutrition

Many patients with active TB experience severe weight loss and some show signs of vitamin and mineral deficiencies. Patients with TB/HIV co-infection are even worse off nutritionally. Nutritional advice and support are important elements in recovery.

Frequent (six times a day) meals with a high-energy and high-protein diet are helpful in the acute stages of the illness.

Multivitamin and mineral supplementation:

• zinc
• vitamin C
• Astragalus
• protein and calorie supplementation—may be necessary where appetite is lacking.

Prevention

• BCG vaccination should be considered in some at-risk populations.
• Maintain immune system function (see Ch 32, Principles of the immune system)
• Sufficient sleep and rest.
• Exercise 30 minutes per day.
• Fresh whole foods including fruit and vegetables.
• Maintain respiratory hygiene.

COMMUNITY-ACQUIRED PNEUMONIA AND THE ATYPICAL INFECTIONS

In general practice, when dealing with community-acquired pneumonia and the atypical infections, the most important thing is to consider them in the differential diagnosis.

In community-acquired pneumonia (CAP), the patient is unwell, with high fever. It is more than a simple URTI. The disease is more common in the very young and the very old. The most common organism is Streptococcus pneumoniae but, in one study, in 22% of cases of CAP where an organism was identified, it was an atypical organism (Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella spp).46

Think of atypical respiratory infections especially in the context of the person with an impaired immune system. A prominent example is Pneumocystis jiroveci (carinii) (formerly PCP) infection in those with HIV infection.

image

FIGURE 41.11 Chest X-ray of pneumonia obtained soon after aspiration may appear normal (A); it takes 6–12 hours for an alveolar infiltrate to develop (arrow, B)

Diagnostic approach

• History—the patient has a chest infection, often productive of purulent sputum, and is systemically unwell.
• Examination—there may be some localising signs on respiratory examination.

Investigations

• Consulting room—there may be a reduction in oxygen saturation (if you have access to a pulse oximeter).
• Pathology—sputum (a properly collected sample) for microscopy, culture and sensitivity (MCS) is important but, if the patient is very unwell, commencing treatment should not be delayed while these samples are being tested.
• Special tests—a chest X-ray will assist diagnosis.

Integrated management

Prevention

Respiratory hygiene and minimising spread of infection is important. Ensure routine immunisations against Haemophilus influenzae, influenza and pertussis (whooping cough).

Some children with specific medical problems require vaccination against invasive pneumococcal disease (IPD) separately from the usual immunisation program. These conditions are listed in Box 41.1.

BOX 41.1 Underlying medical conditions predisposing children aged 9 years or younger to IPD47

• Diseases compromising immune response to pneumococcal infection:

• congenital immune deficiency including symptomatic IgG subclass or isolated IgA deficiency (but children who require monthly immunoglobulin infusion are unlikely to benefit from vaccination)
• immunosuppressive therapy (including corticosteroid therapy ≥ 2 mg/kg per day of prednisolone or equivalent for more than 2 weeks) or radiation therapy, where there is sufficient immune reconstitution for vaccine response to be expected
• compromised splenic fuanction due to sickle haemoglobinopathies, or congenital or acquired asplenia
• haematological malignancies
• HIV infection, before and after development of AIDS
• renal failure, or relapsing or persistent nephrotic syndrome
• Down syndrome.

• Anatomical or metabolic abnormalities associated with higher rates or severity of IPD:

• cardiac disease associated with cyanosis or cardiac failure
• all premature infants with chronic lung disease
• all infants born at less than 28 weeks’ gestation
• cystic fibrosis
• insulin-dependent diabetes mellitus
• proven or presumptive cerebrospinal fluid (CSF) leak
• intracranial shunts and cochlear implants.

Self-help

Maintaining adequate nutrition is important in preventing infection in susceptible children.

Pharmacological

If CAP is suspected, consultation with the local infectious disease physician or microbiology service will guide the GP as to the most appropriate antibiotic to be used.

Ongoing review and/or monitoring

These patients are often very unwell, and hospital admission will need to be considered. There are validated severity scales (e.g. CURB-65) that guide diagnosis, but how to proceed remains a clinical decision.46

Important pitfalls

Perhaps the greatest risk for the GP is of underestimating the severity of the patient’s condition.

Prognosis

The mortality from CAP has altered little since antibiotics became readily available—it is still a significant cause of mortality. In Australia, pneumonia and influenza cause 2% of male deaths and 2.7% of female deaths.48

RESOURCES

Australian Lung Foundation. http://www.lungnet.com.au.

Cancer Council of Australia. http://www.cancer.org.au.

Global Initiative for Asthma (GINA), Global Burden of Asthma. http://www.ginasthma.com.

International Primary Care Respiratory Group (IPCRG). http://www.theipcrg.org.

National Asthma Council Australia. http://www.NationalAsthma.org.au.

World Health Organization. http://www.who.int.

REFERENCES

1 Britt H, Miller GC, Charles J, et al. General practice activity in Australia 2008–09. Canberra: Australian Institute of Health and Welfare, December 2009. Cat. GEP 25; Table 7.2.

2 National Asthma Council Australia (NACA). Asthma management handbook 2006. Melbourne: NACA, 2006;3.

3 Holgate ST, Boushey HA, Fabbri LM, editors. Difficult asthma. London: Martin Dunitz; 1999:183.

4 Strachan DP. Hay fever, hygiene, and household size. BMJ. 1989;299:1259-1260.

5 Goldberg S, Israeli E, Schwartz S, et al. Asthma prevalence, family size, and birth order. Chest. 2007;131(6):1747-1752.

6 Kline JN. Eat dirt. CpG DNA and immunomodulation of asthma. Proc Am Thorac Soc. 2007;4:283-288.

7 Gøtzsche PC, Johansen HK. House dust mite control measures for asthma. Cochrane Database Syst Rev. 2008;2:CD001187.

8 Blackhall K, Appleton S, Cates CJ. Ionisers for chronic asthma. Cochrane Database Syst Rev. 2003;2:CD002986.

9 Kilburn S, Lasserson TJ, McKean M. Pet allergen control measures for allergic asthma in children and adults. Cochrane Database Syst Rev. 2003;1:CD002989.

10 Welsh EJ, Bara AI, Barley EA, et al. Caffeine for asthma. Cochrane Database Syst Rev. 2010;1:CD001112.

11 Thien FCK, De Luca S, Woods R, et al. Dietary marine fatty acids (fish oil) for asthma in adults and children. Cochrane Database Syst Rev. 2002;2:CD001283.

12 Mickelborough TD, Lindley MR, Ionescu AA, et al. Protective effect of fish oil supplementation on exercise-induced bronchoconstriction in asthma. Chest. 2006;129:39-49.

13 Romieu I, Trenga C. Diet and obstructive lung diseases. (Review) Epidemiol Rev. 2001;23(2):268-287.

14 Ram FS, Ardern KD. Tartrazine exclusion for allergic asthma. Cochrane Database Syst Rev. 2001;4:CD000460.

15 Holloway E, Ram FSF. Breathing exercises for asthma. Cochrane Database Syst Rev. 2004;1:CD001277.

16 Nagendra H, Nagarathna R. An integrated approach of yoga therapy for bronchial asthma: a 3–54 month prospective study. J Asthma. 1986;23(3):123-137.

17 Slader CA, Reddel HK, Spencer LM, et al. Double blind randomized controlled trial of two different breathing techniques in the management of asthma. Thorax. 2006;61:651-656.

18 Emelyanov A, Fedoseev G, Krasnoschekova O, et al. Treatment of asthma with lipid extract of New Zealand green-lipped mussel: a randomised clinical trial. Eur Respir J. 2002;20:596-600.

19 Burns JS, Dockery DW, Neas LM, et al. Low dietary nutrient intakes and respiratory health in adolescents. Chest. 2007;132(1):238-245.

20 Riccioni G, Bucciarelli T, Mancini B, et al. Plasma lycopene and antioxidant vitamins in asthma: the PLAVA study. J Asthma. 2007;44(6):429-432.

21 McCarney RW, Brinkhaus B, Lasserson TJ, et al. Acupuncture for chronic asthma. Cochrane Database Syst Rev. 2003;3:CD000008.

22 Dennis J, Cates CJ. Alexander technique for chronic asthma. Cochrane Database Syst Rev. 2000;2:CD000995.

23 Arnold E, Clark CE, Lasserson TJ, et al. Herbal interventions for chronic asthma in adults and children. Cochrane Database Syst Rev. 2008;1:CD005989.

24 McCarney RW, Linde K, Lasserson TJ. Homeopathy for chronic asthma. Cochrane Database Syst Rev. 2004;1:CD000353.

25 Beamon S, Falkenbach A, Fainburg G, et al. Speleotherapy for asthma. Cochrane Database Syst Rev. 2001;2:CD001741.

26 McKenzie DK, Abramson M, Crockett AJ, et al. The COPD-X Plan: Australian and New Zealand guidelines for the management of chronic obstructive pulmonary disease, 2009. Online. Available: http://www.copdx.org.au/guidelines/.

27 Abramson M, Raven J, Skoric B, et al. Prevalence of COPD amongst middle aged and older adults. Respirology. 2003;8(Suppl 2):A59.

28 Wilson D, Adams R, Appleton S, et al. Difficulties identifying and targeting COPD and population-attributable risk of smoking for COPD. A population study. Chest. 2005;128:2035-2042.

29 Tiong LU, Gibson PG, Hensley MJ, et al. Lung volume reduction surgery for diffuse emphysema. Cochrane Database Syst Rev. 2006;4:CD001001.

30 Guo R, Pittler MH, Ernst E. Herbal medicines for the treatment of COPD: a systematic review. Eur Respir J. 2006;28:330-338.

31 Ferreira IM, Brooks D, Lacasse Y, et al. Nutritional supplementation for stable chronic obstructive pulmonary disease. Cochrane Database Syst Rev. 2005;2:CD000998.

32 Celli BR, Cote CG, Marin JM, et al. The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease. N Engl J Med. 2004;350:1005-1012.

33 World Health Organization. Cancer. Online. Available: www.who.int/cancer/en/index.html, 2 April 2010.

34 McAvoy B, Elwood M, Staples M. Cancer in Australia. An update for GPs. Aust Family Physician. 2005;34(1/2):41-45.

35 Cancer Council Australia. Lung cancer—non small cell. Online. Available: http://www.cancer.org.au/Healthprofessionals/cancertypes/lungcancernonsmallcell.htm. Last updated 2003.

36 Cancer Council Australia. Lung cancer—small cell. Online. Available: www.cancer.org.au/Healthprofessionals/cancertypes/lungcancersmallcell.htm. Last updated 2003.

37 Singh M. Heated, humidified air for the common cold. Cochrane Database Syst Rev. 2006;3:CD001728.

38 Linde K, Barrett B, Wölkart K, et al. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev. 2006;1:CD000530.

39 Saxena RC, Singh R, Kumar P, et al. A randomized double blind placebo controlled clinical evaluation of extract of Andrographis paniculata (KalmCold) in patients with uncomplicated upper respiratory tract infection. Phytomedicine. 2010;17(3/4):178-185.

40 Hemilä H, Chalker E, Treacy B, et al. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2007;3:CD000980.

41 Hulisz D. Efficacy of zinc against common cold viruses: an overview. J Am Pharm Assoc. 2004;44:594-603.

42 Vickers AJ, Smith C. Homoeopathic Oscillococcinum for preventing and treating influenza and influenza-like syndromes. Cochrane Database Syst Rev. 2006;3:CD001957.

43 World Health Organization. WHO Library Cataloguing-in-Publication Data. Global tuberculosis control: a short update to the 2009 report. WHO/HTM/TB/2009.426, pp. 4–5.

44 Campbell IA, Bah-Sow O. Pulmonary tuberculosis: diagnosis and treatment. BMJ. 2006;332:1194-1197.

45 Therapeutic Guidelines. Respiratory. North Melbourne: Therapeutic Guidelines Ltd, 2006.

46 Durrington HJ, Summers C. Recent changes in the management of community acquired pneumonia in adults. BMJ. 2008;336:1429-1433.

47 Australian Government. Australian immunisation handbook, 9th edn. 2008: 246.

48 Australian Institute of Health and Welfare. Australia’s health no. 9. Cat. No. AUS 44. Canberra: AIHW, 2004.

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