Nonobstructive Lung Disease and Thoracic Tumors

Vaccination

National guidelines in the United Kingdom recommend influenza vaccination for all adults aged older than 65 years and those in long-term care. The aim is to reduce complications from influenza. In the United States, vaccination is recommended for everyone over the age of 6 months. A Cochrane review, however, has highlighted the paucity of good evidence supporting this approach. Only one randomized control trial was identified that adequately assessed efficacy and effectiveness of vaccination in adults older than 65 years, and this was not adequately powered to detect any effect on complications. It did show an effect against influenza symptoms. That result was obtained even though some evidence suggests that the antibody response to vaccination is attenuated in frail older adults. A further Cochrane review could not find evidence to support the vaccination of health care workers in preventing influenza in adults older than 60 years living in long-term care facilities.

In the United States national vaccination uptake is less than 50%, and in the United Kingdom and Europe only a minority of those eligible for vaccination receive it. Possible explanations include patient concerns regarding side effects, frustration that previous vaccination has not prevented influenza-like illness, and the deferment of vaccination by doctors when patients have a mild upper respiratory tract infection.

Treatment

Neuraminidase inhibitors (zanamivir, oseltamivir) have been the subject of debate with regard to their effectiveness at preventing and treating influenza. Oseltamivir was widely prescribed during the 2009 H1N1 pandemic. These agents must be taken within 48 hours of the onset of symptoms. Current U.K. guidelines recommend their use for at-risk groups, including adults aged older than 65 years when national surveillance schemes indicate influenza is circulating or in localized outbreaks within institutions. Clinical trials have suggested that these agents may reduce symptom duration by 1 or 2 days and decrease hospitalization and death rates in older adults. Further studies are required. The neuraminidase inhibitors are well tolerated and the safety profile among older adults is similar to that in younger adults. The most common adverse effects are nausea, vomiting, and abdominal pain. Zanamivir may cause bronchospasm. Amantadine and rimantadine are only effective against influenza A and are associated with toxic side effects and with rapid emergence of drug-resistant variants. Specific studies in the older adult population are lacking. Routine use of these agents is not recommended.

In the United Kingdom, the National Institute for Health and Care Excellence (NICE) guidance recommends that postexposure prophylaxis with oseltamivir or zanamivir be given to all adults living in residential care facilities, regardless of vaccination status, during localized outbreaks. A recent systematic review found that individuals in care homes that received chemoprophylaxis were significantly less likely to develop influenza than those in homes with no intervention. In the community setting, postexposure prophylaxis is only recommended for high-risk adults (including those older than 65 years) if they have not been vaccinated or if the circulating strain of influenza is known to be different from the vaccination strain. Amantadine is not recommended for use as a postexposure prophylaxis.

Management

The investigation and management of community-acquired pneumonia are discussed in guidelines published by both the BTS and the ATS. Initial empirical treatment is with broad-spectrum antibiotic therapy against Pneumococcus and “atypical” organisms. Current recommendations suggest the combination of amoxicillin plus a macrolide antibiotic for patients with moderately severe pneumonia. An alternative for penicillin-allergic patients is a fluoroquinolone with enhanced pneumococcal activity, such as levofloxacin. Local antibiotic resistance patterns need to be taken into account. Intravenous antibiotic therapy is only required in patients with severe pneumonia or in patients who are unable to take oral preparations. Antibiotic-associated colitis and Clostridium difficile infection are particular concerns with intravenous antibiotics. There is evidence that in patients with severe pneumonia, delay in the administration of the first antibiotic is associated with increased mortality.

Following an episode of pneumonia, it is important to ensure that radiologic changes resolve, particularly in older adults and smokers who are at increased risk of an underlying malignancy. Radiologic clearance is slower in older people. As always, the principle of only ordering tests for which a positive result will be acted on holds.

Nosocomial Pneumonia

The incidence of hospital-acquired pneumonia increases significantly with age and the mortality rate can be as high as 50%. Treatment regimes should cover gram-negative anaerobic bacteria. Pseudomonas species and methicillin-resistant Staphylococcus aureus (MRSA) should also be considered.

Vaccination

Polysaccharide pneumococcal vaccination is recommended for all adults older than 65 years. Reimmunization is unnecessary. Despite strong evidence of pneumococcal vaccination efficacy in preventing invasive pneumococcal disease, there is no evidence that routine vaccination prevents all-cause pneumonia or mortality.

Presentation

The presentation of TB in older adults can be insidious and nonspecific; weight loss, weakness, or a change in cognitive function is sometimes the only manifestation. Dyspnea is often present, whereas hemoptysis and fever are observed less frequently. It is important to consider TB if a patient has a cough or pneumonia that incompletely responds to conventional treatment.

The chest radiographic changes of TB are similar in all age groups, although in older people cavitary disease is less common. Miliary TB is likely in older adults, although the diagnosis is frequently missed. The presence of radiographic manifestations of previous TB infection in an older patient with nonspecific infective symptoms should alert physicians to exclude reactivation. Extrapulmonary TB is uncommon and is often difficult to diagnose. Sites involved include the genitourinary tract, the central nervous system, the lymphatics, and bone. Extrapulmonary TB is more common in children and older people.

Investigation

Pulmonary TB is usually diagnosed by culturing Mycobacterium tuberculosis from sputum. Guidelines suggest that three sputum samples should be sent for culture. In older patients it may be difficult to obtain spontaneous sputum samples, and sputum induction or bronchoscopy with bronchial washings may be required. The presence of acid-fast bacilli (AFB) on Ziehl-Neelsen staining (smear positive) suggests the diagnosis of pulmonary TB; however, M. tuberculosis can take up to 6 weeks to be cultured using conventional techniques. It is important to remember that AFB smear positivity alone does not distinguish M. tuberculosis from nontuberculous mycobacterial infection (NTM). Rapid culture techniques, including polymerase chain reaction (PCR) or gene probe analyses, allow earlier diagnosis. Once a patient has been diagnosed with TB, HIV testing should be performed.

Patients with suspected TB are usually investigated as out­patients; however, smear-positive older adult care home residents should be isolated to prevent transmission. If admitted to the hospital, patients should be isolated until their sputum status is known. If multidrug-resistant tuberculosis (MDR-TB) is suspected, patients should be managed in a negative air pressure room. Patients who are smear positive need to remain isolated until they have completed 2 weeks of antituberculous treatment.

Tuberculin Skin Test

The tuberculin skin test measures cell-mediated immunity against TB. It is positive in both active and latent disease and also in people who have received bacillus Calmette-Guérin (BCG) immunization. False negatives can occur in immunocompromised patients because of anergy. Anergy prevalence increases with age because of a decline in cellular immunity, and the value of the tuberculin skin test is therefore reduced. It is mainly used in the diagnosis of latent TB.

Interferon-γ Tests

Interferon-γ blood tests detect tuberculosis infection by measuring interferon-γ release from T cells in response to antigens that are highly specific to Mycobacterium tuberculosis but are absent from the BCG vaccine. In the United Kingdom they are primarily used to confirm the diagnosis of latent TB in the presence of a positive tuberculin skin test, or in those people for whom a skin test is less reliable (e.g., previous BCG vaccination).

Management

Recommendations for antituberculous therapy do not differ in older people. Initial empirical therapy should consist of a four-drug regime for 2 months (rifampicin, isoniazid, pyrazinamide, ethambutol), followed by a two-drug regime for 4 months (rifampicin and isoniazid). Extrapulmonary TB is treated in the same way, with the exception of TB meningitis, which requires 12 months of treatment. Directly observed therapy may be useful in selected individuals who are at risk of poor compliance. Contact tracing is an important aspect of management, and current recommendations are available in national and international guidelines.

MDR-TB (resistance to rifampicin and isoniazid) is uncommon in the older adult population in the United Kingdom and United States. This is probably because active TB in older adults usually results from reactivation of latent infection that was acquired when there was no effective antituberculous chemotherapy.

Older patients often show a greater incidence of drug toxicity and intolerance. They are more likely to be coprescribed other medication, and this increases the likelihood of drug interactions. Rifampicin, in particular, can reduce the levels of many medications through induction of the cytochrome P450 system. The use of isoniazid has been associated with increased levels of some anticonvulsants and benzodiazepines.

Rifampicin, isoniazid, and pyrazinamide are all associated with gastrointestinal side effects and hepatotoxicity. Hepatic toxicity is increased in older patients. Ethambutol can cause a loss of visual acuity and color discrimination and close monitoring is required in elderly patients whose visual acuity may already be impaired. Isoniazid can cause peripheral neuropathy, particularly in patients with coexisting renal failure. This can be prevented by pyridoxine. Finally, rifampicin may cause bodily fluids to become discolored orange.

Latent TB

Latent TB is defined as a positive tuberculin skin or interferon-γ test, with a normal chest x-ray and no symptoms of TB. Individuals who are identified as having latent TB through contact screening should be offered chemoprophylaxis. In the United States all residents of care homes are screened for latent TB on admission. Those with latent TB are treated with chemoprophylaxis. Treatment regimes comprise either isoniazid alone for 6 months or isoniazid and rifampicin combined for 3 months. It is important to identify and treat latent TB prior to immunosuppressant treatment, particularly anti–tumor necrosis factor-α (anti-TNFα) therapy.

Prognosis

In 2012 in the United Kingdom there were 261 deaths from active TB, 72% of which occurred in adults older than 65 years of age. Many older patients will have long-term sequelae from tuberculous infection. Pulmonary fibrosis is a recognized complication, as is pleural thickening and restrictive lung disease from pleural infection. Historical surgical techniques have also led to chest wall deformities. These patients with restrictive lung disease are at risk of hypercapnic respiratory failure and may require home noninvasive ventilation.