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SOURCE

Source: Blackford MG, Glover ML, Reed MD. Lower respiratory tract infections. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861&sectionid=146071234. Accessed March 31, 2017.

DEFINITION

  • Inflammation of the epithelium of the large airways resulting from infection or exposure to irritating environmental triggers.

ETIOLOGY

  • Most commonly occurs during winter months.

  • Attacks precipitated by:

    • Cold, damp climates.

    • Presence of high concentrations of irritating substances.

      • Air pollution.

      • Cigarette smoke.

  • Most commonly caused by respiratory viruses such as rhinovirus and coronavirus.

  • Bacterial causes may include Mycoplasma pneumoniae, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Chlamydophila pneumoniae.

PATHOPHYSIOLOGY

  • Occurs in all ages.

  • Infection of trachea and bronchi causes:

    • Hyperemic and edematous mucous membranes.

    • Increase in bronchial secretions.

      • Impairs mucociliary activity.

EPIDEMIOLOGY

  • Recurrent acute respiratory infections may be associated with increased airway hyperreactivity and possibly pathogenesis of chronic obstructive lung disease.

RISK FACTORS

  • Cold, damp climate.

  • Air pollution.

  • Cigarette smoke.

CLINICAL PRESENTATION

  • Usually begins as upper respiratory infection with non-specific complaints.

SIGNS AND SYMPTOMS

  • Cough is hallmark symptom and occurs early.

    • Initially nonproductive but progresses to mucopurulent sputum.

    • Persists up to 3 weeks despite resolution of nasal or nasopharyngeal complaints.

  • Nonspecific complaints, such as malaise and headache, coryza, and sore throat.

  • Chest examination: rhonchi and coarse, bilateral, moist rales.

  • Mild to moderate wheezing.

DIAGNOSIS

MEANS OF CONFIRMATION AND DIAGNOSIS

  • History and physical examination.

LABORATORY TESTS

  • Sputum cultures of limited utility.

IMAGING

  • Chest radiographs usually normal, not recommended.

DIFFERENTIAL DIAGNOSIS

DESIRED OUTCOMES

  • Provide comfort to patient.

  • Avoid dehydration and respiratory compromise in severe cases.

TREATMENT: GENERAL APPROACH

  • Treatment symptomatic and supportive in nature.

TREATMENT: NONPHARMACOLOGIC THERAPY

  • Bedrest.

  • Analgesics.

  • Antipyretics.

  • Fluids.

TREATMENT: PHARMACOLOGIC THERAPY

  • Routine use of antibiotics in treatment of acute bronchitis discouraged.

    • If fever or respiratory symptoms persist for >5–7 days or predisposed patient (COPD, immunocompromised, elderly), consider possibility of concurrent bacterial infection.

      • Direct antibiotic therapy toward anticipated respiratory pathogen(s).

      • Empiric treatment with fluoroquinolone usually first line.

MONITORING

  • Patients should contact physician if symptoms do not resolve within 4–6 days.

PROGNOSIS

  • Primarily self-limiting illness and rarely cause of death.

Date Written: March 31, 2017

Contributor: Laura ...

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