What Are Chronic Lung Infections?
Chronic lung infections are those which do not resolve quickly or at all after antibiotic treatment. The most common causes are from chronic obstructive pulmonary disease (COPD), cystic fibrosis, and bronchiectasis, all of which involve inability to clear secretions. All persistent lung infections alternate periods of stability with periods of exacerbation (changes in cough, dyspnea, sputum, or fatigue).
Chronic lung infections are usually due to some compromise in this dynamic action of ventilation–age, immunocompromised, or the dysfunction and tissue destruction of chronic obstructive pulmonary disease (COPD).
Causes of Chronic Lung Infections
Depending on specific illnesses or the degree of debilitation, the respiratory changes that can begin lengthy (chronic) lung infections include:
- Loss of elastic recoil in the chest wall resulting in air trapping and increase in lung capacity and residual volume
- Diminished respiratory muscle strength and endurance
- Loss of alveoli
- Reduction in oxygen and carbon dioxide exchange
- Inability to increase rate of respiratory effort
- Decreased cough or gag reflex (leading to ineffective clearance or aspiration pneumonia
- Decreased ability of cilia to move mucous and bacterial debris upward
The above risks are compounded extensively in closed settings of cloistered immunocompromised persons, such as in nursing homes and facilities and other institutions. Hospital acquired pneumonia is more likely to be drug resistant. Comorbidity is the strongest independent predictor of mortality in patients with chronic lung infections.
Smoking results in most of the respiratory changes cited above. The upward elevator movement of cilia to move inhaled particles, bacteria, etc. out of the pulmonary system become inert. Smoking also is the prime cause of COPD. The destruction of alveoli, decreasing the surface area used for respiration, decreases such that any infection is already synergistic for compromise in gaseous exchange.
A serious complication of stroke is the loss of a gag or swallowing reflex. This creates a scenario in which food and drink meant for the esophagus can get into the lung, providing a suitable growth medium for bacterial.
Those who are immunocompromised (e.g., HIV) are who are pharmacologically immunocompromised (systemic corticosteroid use) may be ineffective in the first lines of defense due to limitations of the innate immune system.
Chronic Lung Infections
- Pneumonia from COPD, aspiration
- Bronchiectasis-related pneumonia (inability to clear secretions)
- Cystic fibrosis-related pneumonia
How Are Chronic Lung Infections Diagnosed?
Although different chronic lung infections are caused by different agents, they can be confusing because of similarities in their signs, symptoms, X-ray findings, and pulmonary compromise. The end result is a common syndrome whose cause may be difficult to identify specifically unless further testing is used.
Since the term “chronic lung infections” is reserved for those that fail to respond to treatment (antibiotics, etc.), the cause of treatment failure is as important as the infectious agent. Diagnosis must include a search for the patient’s underlying host factors, such as age, immunosuppression, and comorbidities. In tandem with this appraisal is identification of the infectious agent, and together, they can individualize treatment according to both the cause of the infection and the cause of the treatment failure.
Diagnosis begins with clinical findings such as dyspnea, sputum production, coughing, and fever. Associated symptoms include congestion, productive cough, chest pain, wheezing, and weight loss. Physical exam to auscultate the lung fields can identify the extent of disease, and X-ray imaging will complement this approach.
Definitive identification of what to treat is based on bacterial cultures, and if these persist as negative, a viral cause is assumed. Viral causes include HIV and the herpes viruses (HSV 1 and 2, Epstein-Barr, cytomegalovirus, or varicella).
Sputum culture: used to pursue the identity of the infectious agent, and sensitivity testing of this organism can demonstrate any antibiotic resistances that have developed from previous antibiotic exposures. If targeted medication fails, further testing is warranted with CT imaging of the chest. If there is a mass or suspicious area on imaging studies, bronchoscopy is used to get deeper washings and/or tissue biopsies.
Blood tests: helpful in identifying the severity of infection via a white blood count and even an allergic or parasitic component based on eosinophils (WBCs common in allergic reactions and parasites).
Pulmonary function testing: to evaluate the degree of lung compromise with functional testing such as spirometry. Spirometry can measure parameters such as vital capacity, expiratory volume, and other flow measures. These results can determine the need for supplemental oxygen.
How Can I Manage Chronic Lung Infections
There is a three-pronged approach to treatment:
- Treatment to eradicate the infectious organism
- Treatment of the respiratory compromise
- Prevention strategies
Based on cultures, the frequent causes of pneumonia and other chronic lung infections can be identified. They can be tested against an assortment of antibiotics for those to which they prove the most sensitive. Unusual bacteria, such as the anaerobic bacteria, will require specific, more potent antibiotics due to their increased virulence and resistances; the Mycobacteria of tuberculosis will require therapy with antitubercular agents for at least 4 months. Fungal infections are treated with antifungal agents.
Viral infections of the lung which fail to resolve are typically due to immunocompromise, so treatment will involve both antiviral agents and reduction of any immunosuppression. Since immunosuppression is the key feature to treating HIV, autoimmune disease, and transplant patients, this must be weighed seriously according to risk-vs-benefit.
By the nature of chronic lung infections, the length of therapy will be longer than what is implemented in common pneumonias and other lung infections.
Persistent treatment failure should prompt investigations to rule out sequestered sites of occult infection in the lungs as a source of continuous re-seeding of infection, such as lung abscesses or empyema.
Treatment of Pulmonary Compromise
The pulmonary compromise of gas exchange between carbon dioxide and oxygen is already significant in comorbidities that make chronic lung infections more likely. The further inflammatory and exudative effects of infection only worsen this. Bronchodilators, mucolytic medication, and assisted ventilation with supplemental oxygen are used to maintain respiratory function until the difficulties are mitigated by successful antimicrobial eradication.
How Can I Prevent Chronic Lung Infection?
Prevention of chronic lung infections includes avoiding behaviors that increase risk, immunizations, and societal adjustments.
Address Behaviors That Increase Risk of Chronic Lung Infections
- Quit smoking: If necessary, there is medication that can suppress the dopamine (reward neurotansmitter) that is released with smoking (varenicline–Chantix)
- Avoid drug abuse: Especially intravenous abuse of illicit substances
- Strict glycemic control: If diabetic
- Avoid toxic environments (e.g., smoky entertainment venues, leaf-burning, etc)
Immunization for influenza and pneumococcus are the most important preventive strategies in prevention of pneumonia, especially for those cloistered in institutionalized settings. Other immunizations for infectious agents that can play a role in chronic lung infections include those for varicella and Haemophilus influenzae.
A person at risk for recurrent or chronic lung infections should live in a smoke-free environment, including at home. Exposure to dander or other allergens should be limited. Inhalation of airborne particles that can lodge in the lungs of those with mucociliary compromise should be avoided (e.g., changing cat litter).
In institutionalized settings, family members of residents should not hesitate to ask administration about infection rates or for accreditation results.
Persons with swallowing or gag reflex abnormalities are in constant danger of micro aspiration, requiring physical therapy and heightened vigilance.
CPAP masks should be used in cases of sleep apnea.