Pulmonary Disease in Elderly
It is only recently that health problems of the elderly have drawn our more active attention in this country. The number of people beyond 65 years of age have significantly increased in the last one or two decades or so. This is partly because of the increase in the total population and partly because of an increase in life span. Many individuals who earlier used to die young, now live longer into old age. This has obviously happened because of the general improvements in socio-economic standards and health care. As a result, one sees more and more elderly people in the hospitals seeking solutions for their health problems.
The issues related to health care of elderly have evoked great interest of internists and the specialists. Old age is one special area of medicine which is rather specialized for handling. Yet one needs to manage an old person as a general physician more often than a specialist.
All body systems including the respiratory tract age with time. But the different alterations which occur in one particular system (e.g. respiratory) are also reflected in the functioning of the other. This is particularly true in old age.
The anatomical and physiological alterations which take place with age not only affect the normal functioning of respiratory system but also the occurrence and course of different diseases. It is important to discuss the different age related changes before we deliberate upon diagnosis and management of diseases.
Age-related changes in Respiratory System
I. Structural changes
Lung elasticity: The two major tissues of lung parenchyma affected by aging are lung elastin and collagen. Due to changes and loss of elastin, there is loss of elasticity resulting in alveolar dilatation, lung hyperinflation and inadequate deflation. Lungs therefore become voluminous and grounded in shape, an appearance similar to that of emphysema. It is for this reason that the terminology senile emphysema got popular although the lungs are not emphysematous in true histological sense.
There is also a progressive increase in respiratory bronchioles and alveolar ducts ductectasia. But the alveolar septae become shortened and flattened causing a decrease in the surface to volume ratio.
Collagen, which is metabolically inert, is present in abundance in lungs. Due to an increase in the number of cross-links between sub-units of collagen, there is increased rigidity.
Changes in chest wall: There is sclerosis and calcification of joints of ribs with sternum and spinal column. In addition, osteoporosis of vertebrae may cause kyphosis. The chest wall changes decrease its compliance limiting chest expansion.
Changes in compliance of lung parenchyma and chest wall take place in opposite directions. Since the increase in chest wall rigidity is far more than the decrease in lung elastic recoil, the overall change is that of a decrease in compliance of the respiratory system, causing increased work of respiratory muscles.
Respiratory muscles: Respiratory muscles atrophy with age causing decrease in respiratory muscle strength and endurance. Both maximal inspiratory (Pimax) and expiratory (Pemax) pressures decrease in both sexes. There is a marked inter-individual variability in respiratory pressures. Physically active individuals have greater muscle endurance because of the training effects.
Miscellaneous changes: There are some alterations in respiratory control i.e. a diminished responsiveness to hypoxaemia and/or hypercapnia. This could further be attributed to changes in function of the peripheral chemo-receptors or the respiratory centre or both.
Alterations in pulmonary circulation are generally mild. There is a minor increase in pulmonary vascular resistance and pulmonary artery wedge pressure during exercise. These changes have little physiological or clinical significance.
II. Functional changes
Alterations of lung functions are important and clinically relevant. There is a gradual decline in vital capacity (VC) and forced expiratory volume in first second (FEV1). On the other hand, the residual lung volume, functional residual capacity (FRC) and the total lung capacity are increased. These changes indicate some degree of air trapping in the lung. The air flows are reduced and the percent ratio of FEV1 to VC may also be low. Total airway resistance at FRC does not change but the significant increase which occurs in the peripheral airway resistance is compensated by a decrease in central airway resistance.
There is a gradual decline with age of diffusion capacity (DLCO) of the lungs. Both the membrane component (Dm) and pulmonary capillary blood volume (VC) decrease but the decline in Dm is greater. Low DLCO along with increased ventilation ? perfusion mismatching cause an age-related fall in arterial oxygen pressure (PaO2). The alveolar oxygen pressure (PAO2) remains unaltered but the alveolar arterial oxygen gradient (PA-aO2) is increased. There are no alterations in either PaCO2 or pH of arterial blood.
Besides the functions of other organ systems, exercise, sleep, psychological and sexual activities also alter with age and affect the functioning of respiratory system either directly or indirectly. Exercise capacity is decreased and sleep disturbed. The diminished gastrointestinal motility, limited neurological responses, diminished cardiac output and increased dysfunction, all affect the normal functions of respiratory systems, occurrence of diseases and their management strategies.
III. Impaired Defence Mechanisms
Both the local and systemic defence mechanisms are altered in old age. There is impairment of cough and other respiratory reflexes. Mucociliary function of the respiratory tract is depressed and the clearing of aspirated particles is delayed. The immunological defences involving different cells including the lymphocytes and macrophages are altered. There is decreased phagocytosis and microbial killing by the macrophages. Both antigen presentation and cytokine production are impaired.
In view of the impairment of both non-immunological and immunological mechanisms, the chances of occurrence of respiratory infections are increased and their resolution delayed.
Respiratory disease in elderly
In addition to the above listed factors which predispose to disease occurrence, there are several other variables which influence the clinical spectrum and behaviour of different respiratory diseases. The cumulative effect of exposure to different disease-producing agents which has taken place in the preceding years, becomes manifest. Tobacco smoking, occupational and environmental exposures are important examples of some of these exposures. Similarly, the presence of comorbid conditions such as diabetes mellitus, hypertension and other cardiovascular diseases, presence of gastrointestinal and neurological illnesses affect the occurrence and management of respiratory diseases.
Specific Diseases
I. Infections
Pneumonias: Pneumonia is the most frequent respiratory infection of old age. The factors predisposing to respiratory infection have been listed earlier. Pneumococcal pneumonia is perhaps the commonest form of community acquired pneumonia. Nosocomal pneumonias in hospitalized patients occur due to Klebsiella and other Gram negative bacilli or sometimes, staphylococci.
Haemophilus influenzae, influenza, other viral and mycoplasma pneumonias are also common especially in patients with chronic obstructive pulmonary disease (COPD). Both viral and bacterial pneumonias constitute an important cause of increased morbidity and mortality.
Diagnosis of pneumonia is suspected from the clinical picture of fever, increased malaise, fatigue and weakness, cough with or without sputum production and/or hemoptysis. Diagnosis is established on presence of polymorphonuclear leucocytosis and chest roentgenological findings. Sputum should be examined by Gram’s staining and culture. If sputum is not available, or patient shows poor (or no) response to treatment, bronchoscopic examination or other invasive procedures may be required to obtain material for microbiological investigations.
Treatment is administered with antibiotics and other supportive measures. Choice of antibiotic depends upon the causative organism which is either established or suspected. Empirically, a combination of amoxycillin and clauvulanic acid or macrolides are preferred for community acquired infections. Second generation cephalosporins or quinolones may also be used. For nosocomal pneumonias, parenteral antibiotics are required. A combination of an aminoglycoside and a second or third generation cephalosporin is used until a microbiological guidance becomes available. Treatment is required to be reviewed every 48 hours or so.
Tuberculosis: Old age is particularly susceptible to tuberculosis. It is mostly reactivation of a previously quiescent tubercular focus due to a recent insult or impairment of immunological defences which causes active tuberculosis. Primary tuberculosis due to reinfection may also occur. Symptoms are relatively fewer and physical examination nonspecific. Tuberculin test cannot be relied upon in view of its being positive in over 50 percent of healthy population of this country. Moreover, it is frequently negative in old age even in the presence of an active disease.
Diagnosis of tuberculosis is generally made on clinical features and roentgenological appearances of upper lobe infiltrates with/without cavitation, or a diffuse miliary pattern. Sputum, if available, offers the best choice for diagnosis. Smear examination if repeated thrice, is likely to be positive in upto 60 percent of patients with active tuberculosis. Many a patients either do not produce sputum or are unable to cough it out. Bronchoscopy is helpful in such cases and examination of bronchial secretions offers an additional positivity of about 20 to 30 percent. Transbronchial lung biopsy is of great help in patients with diffuse miliary disease.
Tuberculosis is managed on similar lines as in any other case. The initial intensive phase involves administration of four potent drugs (isoniazid, rifampicin, pyrazinamide and ethambutol) for two months followed by four months of isoniazid and rifampicin. Aminoglycosides such as streptomycin and amikacin are avoided in old age. Similarly, ethambutol dosage should not be high and duration not prolonged for fear of ocular toxicity. It may not always be easy to monitor for visual field defects in old age.
II. Chronic Obstructive Pulmonary Disease (COPD)
COPD characteristically starts in middle or past middle age and progresses slowly. A patient who has developed the disease at about 50 years of age, therefore, is likely to have a well established and advanced disease by the time he reaches 65 years or over. He is severely disabled because of breathlessness and suffers from frequent exacerbations due to recurrent infections and other complications.
COPD encompassing chronic bronchitis and emphysema, occurs most often in chronic and heavy smokers. Old age by itself does not cause COPD although the structural and functional alterations which take place with age, do contribute to lung function impairment, disease morbidity and mortality. Senile emphysema, a term which connotes age related emphysema is more a misnomer, than a disease. It only implies the presence of hyperinflated lungs due to increased elasticity. There is no true alveolar destruction unless the individual resorts to smoking which is likely to initiate true emphysematous changes and accelerate lung function decline.
Dyspnoea is a common symptom in the elderly even in the absence of COPD. This, in part is a general symptom and in part, related to increased cardio-respiratory demands. With aging, there is progressive worsening of cardiac disorders contributing to dyspnoea. It is worse if there is associated obesity, which is not uncommon in old age. Obesity causes increased work of breathing and respiratory muscle weakness.
Diagnosis of COPD is relatively simple. Clinical features and chest roentgengraphy, further aided by spirometric measurements are fairly diagnostic. Electrocardiography, echocardiography and sometimes exercise testing are required for cardiopulmonary assessment. Blood gas measurements are required to diagnose the presence and severity of respiratory insufficiency.
COPD is managed with general advice of stopping smoking, bronchodilators, expectorants and treatment of infections. For long term rehabilitation programmes, inspiratory muscle training and general exercise reconditioning are very useful. Domicilliary, long term oxygen therapy has been shown to benefit most such patients.
Acute exacerbations and respiratory failure are managed more actively with antibiotics, increased oxygen administration and other supportive therapy. Endotracheal intubation and a short period of assisted ventilation may be required in a severely hypoxic and hypercapnic patient.
It is better to manage these patients conservatively rather than aiming to achieve normal blood gas values. Mechanical ventilation, even if required, should be weaned off as early as possible. When prolonged, there develops respiratory muscle weakness and dependence on assisted ventilation. Unfortunately, we do not have a back up system of domicilliary care to provide home ventilation and other supports. Invariably therefore, a prolonged period of assisted ventilation becomes a source of an unending agony and misery to the patient and the family. It also burdens severely the already strained public health services in most instances.
Bronchial Asthma
Chronic airways obstruction in old age is more often caused by COPD but can occasionally be attributed to asthma which is either present from younger age or rarely starts de novo at old age. Asthma in the elderly needs to be differentiated from other causes of wheezing of which COPD is the most important. Left heart failure, pulmonary thromboembolism and central airway obstruction due to lung tumours are some other important causes. Eosinophilic syndromes, bronchial carcinoids or foreign body aspiration may also simulate a clinical picture of asthma.
Early recognition of asthma is important for efficient management. Asthma in the elderly is relatively poorly tolerated and requires more aggressive management requiring hospitalization earlier than late. An acute episode can prove to be fatal unless managed in time.
Bronchial hygiene is of particular interest in the elderly especially in the presence of airways obstruction. In view of the impaired defence mechanism, poor reflexes and weak respiratory muscles, an elderly patient is unable to cough and expectorate effectively. Bronchial secretions, being viscid and thick, may block respiratory passages and rapidly cause pneumonia and respiratory failure. Nebulization of bronchodilators and mucolytic agents and maintenance of hydration are important in liquefying the secretions. Parenteral corticosteroids and antibiotics are also required for acute exacerbations.
Respiratory physiotherapy is important to maintain bronchial patency. Expulsive coughing and other chest physical therapy (CPT) procedures such as chest percussion and vibration are helpful.
III. Lung Tumours
Both primary and metastatic lung tumours are common. Metastases may arise from cancers of breast, gastrointestinal tract, kidneys and urinary bladder, prostate and genital tract.
Primary Lung cancer occurs more commonly in the 6th and 7th decades of life. The mean age of lung cancer in India is reported to be lower (54-56 years) than in the West where it is above 65 years, in both males and females. There is evidence to suggest that the mean age of lung cancer is rising. In fact, the contemporary age incidence in India is similar to what was reported in the West some 40 years ago.
There are some differences in the histological types of cancer amongst smokers and nonsmokers in patients above 40 years of age. Squamous cell is most common amongst smoker and adenocarcinoma amongst the nonsmokers.
Diagnosis of cancer poses special problems. Invasive investigations are often required for which the patient is generally hesitant. Management plans involving both surgical and nonsurgical treatments are also cumbersome and generally tiring for a old person. Both radio and chemotherapy are poorly tolerated. Above all, the results are not curative in most instances. It is therefore palliative treatment which is often resorted to.
IV. Miscellaneous respiratory problems
1. Primary alveolar hypoventilation
This may result from either a low perfusion state in the region of central respiratory chemo-receptors or the brain micro-infarcts. Both these changes are more likely in the aged. The syndrome is characterized by chronic arterial hypoxaemia and hypercapnia. The patient therefore, presents a picture simulating that of chronic cor pulmonale and respiratory failure.
2. Obesity hypoventilation syndrome
A clinical picture of chronic hypoxaemia and hypercapnia is seen in obese patients? obesity hypoventilation syndrome. The primary cause in this condition is decreased respiratory centre responsiveness due to alterations in hormonal function. Weight reduction and progesterone therapy is the treatment of choice.
3. Altered breathing
Cheyne-Stokes breathing is common in the elderly. It is characterized by regular cycles of gradually increasing and decreasing depth of respiration. It is perhaps because of hypoperfusion of the respiratory centre. Its presence in patients of congestive heart failure supports this mechanism.
4. Sleep apnoea syndromes (SAS)
Although sleep apnoea syndromes are not age-specific, they tend to occur more commonly in the old because of the factors described earlier i.e. hypoperfusion, micro-infarcts, hormonal and neuromuscular changes. Both central and obstructive sleep apnoea may occur. There are frequent periods of apnoea or hypopnoea during sleep. This causes arterial oxygen desaturation and effects of hypoxaemia.
5. Pulmonary Aspiration
Aspiration of gastric contents is common due to reduced levels of consciousness and gastroesophageal motility problems. This is even more likely in semiconscious and unconscious patients following strokes, seizures or other diseases concurrently present in the aged. While acute massive aspiration may prove to be fatal, pneumonia is a common sequelae of aspiration.
General issues in management
Diagnosis is relatively difficult in view of the limitations posed due to advanced age. Invasive investigations are often fraught with risks due to concurrent diseases. Moreover, the patient himself/herself may not be favourably disposed to several tests.
Disease-treatment in old age is no different although the management poses problems because of increased drug toxicity, poor tolerance and compromised functions of other systems. Choice of drugs is largely similar. Terminal care involving endotracheal intubation, resuscitation and assisted ventilatory management poses important ethical and social issues. In summary, the problems in the elderly are more common and serious but management is rather restrictive. One has to weigh several options to provide care and relief to the diseased.
Table 1: A summary of normal respiratory alterations with age
| I. | Structural | ||
|---|---|---|---|
| 1. Lung | Elasticity | Decreased | |
| Compliance | Increased | ||
| 2. Chest wall | Rigidity | Increased | |
| Compliance | Decreased | ||
| II. | Lung Function | ||
| 1. Spirometry | V.C. | Decreased | |
| FRC, RV | Increased | ||
| 2.Diffusion Capacity | (DLCO) | Decreased | |
| 3.Blood gases | PaO2 | Decreased | |
| PaCO2 | Unchanged | ||
| pH | Unchanged | ||
| III. | Lung Defences | ||
| 1. Nonimmunological | |||
| Cough reflex | Impaired | ||
| mucocilliary | Impaired | ||
| 2. Immunological | |||
| Phagocytosis | Decreased | ||
| Microbial killing by macrophages | Impaired | ||
| Lymphocyte function | Impaired |
Table 2: Factors influencing disease occurrence and management in old age.
- A. Age related alterations (Table 1)
- B. Cumulative Exposures?
- Smoking?
- Environmental pollution?
- Occupational exposures?
- C. Comorbid conditions?
- Systemic illnesses (Diabetes, hypertension etc.)?
- Altered function: Neurological, Gastrointestinal, Cardiovascular?
- Treatments for concurrent/comorbid conditions: Corticosteroids,? Antihypertensive/antidiabetic drugs?
- D. Difficulties of diagnosis and treatment?
- Atypical presentations Delayed/misdiagnosis?
- Problems in performing invasive tests and interventions?
Dr S.K.Jindal, Professor & Head, Department of Pulmonary Medicine,
Postgraduate Institute of Medical Education and Research, Chandigarh, India.
