Introduction
The frequency of physician visits and over-the-counter remedy sales underscores the high prevalence of cough in the elderly, but epidemiological studies have often lacked precision. Nevertheless, respiratory tract infections affecting the nose, larynx, and/or whether viral, bacterial, or both- emerge as the primary culprits behind acute cough. This is particularly concerning for older people, and the challenges may be exacerbated in community living and institutional settings.
Various viruses (rhinovirus, influenza, respiratory syncytial viruses) and bacteria (Hemophilus influenza, Streptococcus pneumonia, Bordetella pertussis) play crucial roles, with viral infections posing a risk of community-acquired pneumonia. Successful diagnosis hinges on thorough clinical examination and patient history, supplemented by chest X-rays, viral and bacterial cultures, and serological testing. Treatment includes antibiotics and non-specific antitussive therapy.
What Is Cough?
Cough is a fundamental protective reflex against airway aspiration, often heightened by irritants like respiratory viral infections. While typically self-limited, some individuals endure prolonged coughing for weeks or more. The conventional view links chronic cough to the triad of asthma, GERD (gastroesophageal reflux disease), and rhinosinusitis, guiding its management for decades. Clinicians frequently encounter chronic cough cases defying classification within this paradigm, prompting a suggestion to reconsider chronic cough as a distinct disease marked by inherent pathophysiology involving cough reflex hypersensitivity.
These evolving perspectives on cough’s pathogenesis necessitate reevaluating its epidemiological features and associations, particularly in individuals with multiple comorbidities, a common scenario in older adults. Also, there is a lack of comprehensive epidemiological studies examining potential links between comorbid conditions and cough in the aged population. Given that a significant portion of cough patients belongs to the middle-aged or elderly demographic, addressing this gap is crucial for informed clinical decision-making.
What Are the Categories of Cough to Be Considered in the Elderly?
The categories to be considered in the elderly are:
-
Acute and Chronic Cough: Defining acute cough lacks uniform agreement, often delineated by three weeks. The transition to chronic cough typically occurs around the eighth-week mark, with the interim period termed ‘subacute’. Some conditions, inherently chronic, such as COPD (chronic obstructive pulmonary disease), asthma, and bronchopulmonary cancer, can be considered. Conditions like post-nasal drip may exhibit both acute and chronic manifestations, contributing to prolonged cough. Most acute coughs in the elderly stem from Upper Respiratory Tract Infections (URTI), sometimes progressing to chronic coughs.
-
Wet and Dry Cough: Though subjectively assessed, the terms ‘wet’ and ‘dry’ offer limited diagnostic value. A dry cough indicates acute laryngitis, URTI, or chronic conditions like GERD and asthma. Wet cough is associated with bronchopulmonary diseases like chronic bronchitis, cystic fibrosis, and bronchiectasis. While wet cough is typically linked to mucus production, it can also occur in conditions like post-nasal drip. Qualitative as they are, these terms guide diagnostic considerations and suggest appropriate antitussive approaches.
-
Age and Cough: While extensive studies exist on acute cough in children, investigations often neglect age distinctions in adults. Yet, the pathology-inducing cough and physiological mechanisms in the upper airways evolve with age. Elderly individuals may exhibit a weaker cough response to stimuli like distilled water aerosol. Gender-related differences, with women displaying higher sensitivity to cough-inducing aerosols, may also influence cough dynamics, although the impact of this age difference is not well-documented. Notably, female predominance is observed in specialist cough clinics and community practice among the aged.
What Are the Causes of Cough in the Elderly?
Examining cough in various populations, especially in the elderly, requires consideration of distinct settings: institutionalized or home care facilities for the elderly and respiratory or general medical clinical units for children and young adults. Some causes of cough in the geriatric population may include:
-
Acute Rhinitis and Rhinosinusitis: These coughs are induced by laryngeal, tracheal, and bronchial inflammation and require infection extension into the lower respiratory tract or nasopharyngeal secretions reaching the larynx. Post-nasal drip is implicated in chronic cough, and viruses like rhinovirus, adenovirus, and coronavirus, commonly causing upper respiratory infections, may contribute to lower airway infections, especially in the elderly. Bacterial infections, often Streptococcus pneumonia or Hemophilus influenza, can lead to acute bronchitis.
-
Acute Laryngitis: Cough stems from an irritated or inflamed larynx, potentially triggered by ascending mucus irritating the vocal folds. Acute laryngitis, identified by sensations of irritation or soreness in the laryngeal region, can occur independently of tracheobronchial symptoms.
-
Acute Viral Bronchitis (Viral Tracheobronchitis): Viruses causing upper respiratory infections may reach the lower respiratory tract, contributing to viral bronchitis. Rhinovirus, a frequent culprit, is associated with acute asthma exacerbations and infections in COPD and cystic fibrosis. Respiratory syncytial virus (RSV), influenza, coronavirus, and parainfluenza can involve the lower respiratory tract, with RSV being particularly prevalent in the elderly.
-
Bacterial Pneumonia: Approximately five to ten percent of adult tracheobronchitis cases progress to bacterial pneumonia, with agents like Mycoplasma pneumonia, Chlamydia pneumonia, and Bordetella pertussis commonly detected in the elderly. Comorbidities, including neurological disorders and alcoholism, may contribute to a weak cough reflex and increase the risk of bacterial pneumonia.
What Is the Diagnosis and Management of Cough in the Elderly?
For most patients, diagnosing the cause of a cough relies on patient history and physical examination. Elderly patients may necessitate more advanced tests due to potentially masked symptoms. While infections often impact the entire respiratory system, signs and symptoms might manifest in specific areas.
Viral Infections: Differentiating viral influenza from the common cold is vital in anticipating potential bacterial pneumonia. Influenza presents with sudden malaise, cough, fever, myalgia, headache, chest and nasal symptoms. RSV infection, more severe in the elderly, requires careful diagnosis due to slower and less sensitive tests. Clinical examination nuances may help distinguish RSV from influenza.
Nasal Infections: Diagnosing nasal infections relies on patient history and symptoms. Radiographs may lack clarity, and computerized axial tomography scans offer better sinus delineation. Bacteriological and serological tests aid in identifying the infective agent for appropriate chemotherapy.
Acute Bronchitis: Distinguishing between viral and bacterial bronchitis can be challenging clinically. Chest X-rays are recommended if pneumonia is suspected, especially in the senior individuals, but their utility might vary. Sputum gram stains and culture may lack precision, and serological tests, particularly for influenza and B. pertussis, can assist in selecting appropriate therapy.
Bacterial Pneumonia: Its classical signs may be absent in the elderly, emphasizing the need for careful assessment. Tachypnea may be noticeable, and a chest x-ray is crucial in distinguishing between viral and bacterial pneumonia. Patient grading systems help predict survival likelihood and guide the assessment of ventilatory support necessity.
Treatment:
Prevention and Prophylaxis: Annual influenza immunization for individuals over 60 or 65 is a standardized practice, although its efficacy is limited. Chemoprophylaxis with antiviral agents can be effective within 48 hours of symptoms.
Anti-viral Agents: Antiviral agents, effective against influenza A and B, reduce severity and duration if administered promptly. Sialidase inhibitors within 48 hours of symptoms onset can also be effective.
Anti-bacterial: Controversy surrounds antibacterial use in respiratory infections. Antibacterial therapy is valuable when a bacterial infection is confirmed, but distinguishing bacterial from viral is difficult. In older individuals, caution and individualized decision-making are crucial.
Other Treatments: Bronchodilators and corticosteroids may play a role in specific cases. Protussive therapies like humidified air and guaifenesin show limited evidence of effectiveness. Treatments for nasal infections may include antihistamines, vasoconstrictors, atropinic agents, and corticosteroids, with the efficacy varying. First-generation antihistamines may have more substantial antitussive effects due to central nervous sedation.
Antitussive Therapy Indications: It is warranted when the cough disrupts sleep or when inflammation causes the cough to be painful, as in acute laryngitis or bronchitis. Social reasons, such as annoyance to family members or coworkers, can also prompt patients to seek cough remedies.
Cautions in the Elderly: In the elderly, prolonged and excessive coughing can be debilitating. Antitussive agents, commonly used by elderly patients, may lead to adverse effects like mental confusion, nausea, and constipation (especially with opioids), which can be particularly undesirable. While it is traditionally believed that antitussive should not be used for ‘wet’ coughs, evidence supporting this notion is limited.
Dosage Considerations: The effectiveness of antitussive drugs is often questioned due to low doses, with some studies suggesting slight improvement over placebos. Patients, however, often report relief, mainly in soreness and improved sleep, despite the limited efficacy of these drugs.
Placebo Effects: Placebo responses to antitussive drugs are well-documented, with some studies suggesting minimal efficacy compared to placebos. However, the widespread belief in their effectiveness, the relief of symptoms, and the facilitation of sleep contribute to their continued popularity and use. The potential for adverse effects, including addiction, appears lower when the drugs’ effectiveness is close to that of a placebo.
Conclusion
In older individuals, diagnosing and managing cough poses unique challenges due to age-related complexities and the potential for adverse effects from medications. Viral infections, bacterial pneumonia, and nasal infections are common culprits. Understanding the causes and management of cough in older adults involves a balance between specific and symptomatic approaches tailored to individual needs considering age-related factors.
