Differential diagnosis 


  • other respiratory infection

    • pneumonia

    • bronchiolitis

    • sinusitis

    • common cold

    • pharyngitis

    • tuberculosis

    • Mycoplasma pneumoniae
    • Chlamydia pneumoniae
    • pertussis

  • reactive airway disease

    • asthma

    • allergic aspergillosis

    • occupational exposures

    • chronic bronchitis

  • bronchiectasis

  • heart failure

  • other causes of cough or wheeze

    • angiotensin-converting enzyme (ACE) inhibitor use

    • gastroesophageal reflux disease (GERD) (with chronic aspiration)

    • other aspiration syndromes (including aspiration pneumonia)

    • smoke inhalation or other toxic inhalational exposure

    • foreign body aspiration

    • bronchogenic tumor (lung cancer)


Testing 


  • use of procalcitonin levels or C-reactive protein point-of-care testing can safely reduce antibiotic use in lower respiratory tract infection

    • interpretation of procalcitonin levels

      • procalcitonin < 0.1 mcg/L—antibiotics strongly discouraged

      • procalcitonin 0.1-0.25 mcg/L—antibiotics less strongly discouraged

      • procalcitonin 0.25-0.5 mcg/L—antibiotics recommended

      • procalcitonin > 0.5 mcg/L—antibiotics strongly recommended

  • other laboratory testing generally not needed

  • chest x-ray 

    • usually not indicated in healthy nonelderly adults in absence of vital sign abnormalities or asymmetric lung sounds

    • may be warranted in patients with cough lasting
> 3 weeks in absence of other known causes

    • does not appear to change outcomes or management in most adults with acute cough 

  • if pertussis suspected, perform diagnostic testing

  • sputum culture usually not helpful (usually negative or normal respiratory flora) 

  • pulmonary function testing unnecessary in otherwise healthy patients


Treatment 


  • increasing fluid intake during respiratory infection has unknown benefits and harms

  • routine antibiotic treatment not recommended for uncomplicated acute bronchitis (regardless of duration of cough) unless pertussis suspected

    • patient satisfaction with care for acute bronchitis depends more on physician-patient communication rather than on antibiotic treatment 

    • efficacy of antibiotics for reducing cough or overall symptoms appears limited and antibiotics associated with adverse effects 

    • antibiotics may reduce cough in children with ­prolonged moist cough 

    • limited evidence for comparative efficacy for ­different antibiotics 

      • azithromycin might reduce clinical failures compared with amoxicillin or amoxicillin-clavulanate in patients with acute respiratory tract infection 

      • roxithromycin may be as effective as amoxicillin for lower respiratory tract infection 

    • strategies shown to reduce antibiotic use include 

      • patient information handout 

      • displaying of poster-sized letters
in examination rooms stating clinician
commitment to avoid inappropriate antibiotic prescribing for adults with acute respiratory infection

      • print-based and computer-assisted decision ­support strategies for reducing antibiotic use 

      • using diagnostic label of “chest cold” instead of acute bronchitis reported to reduce dissatisfaction with not receiving antibiotics 

      • procalcitonin levels or C-reactive protein point-of-care testing 

  • Pelargonium sidoides extract (EPs 7630), especially liquid preparations, may reduce symptoms and hasten resolution of acute bronchitis in adults with low rate 
of adverse effects

  • beta-2 agonists (such as albuterol) might reduce
cough in adults with evidence of airflow
obstruction, but do not appear to reduce cough
in children 

  • antitussive agents

    • most nonprescription oral medicines for acute cough do not have good evidence of benefit

    • in adults, medications that may reduce acute cough include dextromethorphan, guaifenesin, bromhexine, and dexbrompheniramine/pseudoephedrine 

    • in children, nonprescription medicines

      • do not appear effective for acute cough and may have rare but serious side effects including death, convulsions, rapid heart rates, and decreased levels of consciousness

      • FDA recommendations 

        • should not be used in children < 2 years old 

        • avoidance in children < 4 years old 
supported

  • insufficient evidence to recommend Chinese medicinal herbs 

  • elimination of environmental cough triggers and vaporized air treatments (especially in low-humidity environments) may be helpful but lack supporting evidence

  • informational handouts may lower rate of return visits for lower respiratory tract symptoms 


Prognosis


  • mean duration of cough 2-4 weeks in adults with acute cough illness

    • >1 month in 25% 

    • up to 6 months (rare)


Prevention 


  • recommend smoking cessation

  • handwashing 

  • zinc supplementation may reduce incidence of 
acute lower respiratory tract infections in preschool children 


Alan Drabkin, MD, is a senior clinical writer for DynaMed, a database of comprehensive updated summaries covering more than 3,200 clinical topics, and assistant clinical professor of population medicine at Harvard Medical School.