Pneumonia in the elderly

Burden. Pneumonia is a major cause of hospitalisation and death in old age — about two out of three pneumonia admissions are patients over 70. It is often the terminal event in frailty and dementia ("the old man's friend"), and carries much higher mortality than in younger adults.

Predisposing factors specific to ageing. Immunosenescence with a poor IgM response to pneumococcal polysaccharide, impaired cough and swallowing reflexes causing silent aspiration, reduced mucociliary clearance, loss of lung elastic recoil and "inflammageing", reduced chest wall compliance, poor oral hygiene and edentulism, malnutrition, sarcopenia, and structural airway change (bronchiectasis, old TB scarring, tracheobronchomalacia).

Aetiology. S. pneumoniae, H. influenzae and respiratory viruses predominate, while Legionella, Mycoplasma and Chlamydophila are less common than in younger adults. In nursing home residents, aspiration pneumonia, Gram-negative enteric bacilli and anaerobes are frequent. Multi-microbial infection is common. In India also consider tuberculosis and aspergillosis in post-tubercular cavities.

Atypical presentation. Fever and cough are absent in 30–40%. The classical lobar picture is rarely complete. Common presentations are delirium, falls, sudden functional decline, anorexia, incontinence, tachypnoea alone, or decompensated heart failure or diabetes. Signs to look for: respiratory rate > 30/min, heart rate > 110/min, fever or hypothermia. Tachypnoea is the most sensitive early sign.

Diagnostic approach. Chest radiograph to separate pneumonia from bronchitis; CT if the film is normal but suspicion is high; point-of-care lung ultrasound is very useful in nursing homes and home care. Leucocytosis may be absent; check CRP, renal function and glucose, and oxygen saturation. In hospitalised patients take blood cultures and sputum. Assess severity with CURB-65, remembering that age ≥ 65 already scores one point.

Management and prevention. Decide on site of care using severity, frailty and the ability to be cared for at home. Give empirical antibiotics covering pneumococcus and H. influenzae, with anaerobic cover in nursing home/aspiration pneumonia, renally adjusted. Add oxygen, hydration, early mobilisation, VTE prophylaxis, nutrition, swallow assessment and delirium prevention. Review at 48 hours; failure to improve suggests resistance, tuberculosis, empyema, an alternative diagnosis or underlying lung cancer (especially if shadowing persists at 12 weeks). Prevent with influenza, pneumococcal and COVID-19 vaccines, oral hygiene, smoking cessation, and review of sedatives, antipsychotics and PPIs.

Respiratory syncytial virus (RSV) is now a vaccine-preventable cause of pneumonia in the elderly. Following the 2023 licensure of adjuvanted and mRNA RSV vaccines, the 2024 ACIP recommendation is a single lifetime dose of RSV vaccine for all adults aged 75 and above, and for those aged 50–74 with risk factors (chronic lung or heart disease, diabetes, immunocompromise, frailty, nursing home residence). RSV causes severe lower respiratory infection and exacerbations in older adults comparable to influenza, and vaccination is now part of the standard geriatric immunisation package alongside influenza, pneumococcal and COVID-19 vaccines.