• respiratory tract infection with wheezing or coughing (with or without sputum) 


  • sixth most common diagnosis made during family physician visits

Possible risk factors 

  • underlying predisposition to bronchial reactivity during viral infection

  • immunocompromise

  • exposure to persons with respiratory complaints 

Associated conditions

  • asthma


  • viral infection (most common) in healthy adults

    • most commonly isolated viruses in large series

      • influenza A and B

      • parainfluenza

      • respiratory syncytial virus

      • coronavirus

      • adenovirus

      • rhinovirus

    • viruses more common than bacteria among elderly patients hospitalized for non-pneumonic lower respiratory tract infection

  • nonviral agents (minority of cases) including

    • Mycoplasma pneumoniae

    • Chlamydia pneumoniae

    • Bordetella pertussis

    • Legionella

    • Haemophilus influenzae

    • Streptococcus pneumoniae

    • Moraxella catarrhalis
  • noninfectious causes include inhalation of toxic substances such as 

    • cigarette smoke

    • sulfur dioxide

    • nitrogen dioxide

    • ammonia


  • bronchial edema and mucus formation leads to sputum production, cough, and symptoms of airway obstruction

Clinical presentation 

  • patients with acute bronchitis or upper respiratory tract infection (URI) have considerable overlap in symptoms and signs

  • symptoms may include

    • cough (productive or nonproductive)

    • fatigue due to nocturnal cough 

      • sputum production 

        • clear or purulent (about 50%) 

        • sputum color may not be associated with bacterial infection in patients with acute
cough and no underlying chronic lung

      • dyspnea on exertion

      • wheezing, rhonchi, or other signs of 

  • may have accompanying URI symptoms (for example, fever, sore throat, nasal congestion, runny nose)

Past medical history (PMH) 

  • ask about history of asthma

Social history (SH) 

  • ask about smoking or other toxic inhalant exposures


  • General physical

    • may have low-grade fever

    • practitioner interpretation of common clinical signs (such as fever, tachypnea, and chest signs) may be unreliable in preschool children

  • HEENT 

    • may have rhinitis or pharyngitis

    • may have conjunctivitis or otitis media if adenoviral infection

  • Neck

    • may have lymphadenopathy

  • Lungs

    • lung examination useful but not diagnostic

    • wheezing, rhonchi, prolonged expiratory phase or other obstructive signs may be present but not essential

Making the diagnosis

  • no clear diagnostic criteria have been established

  • cough in the absence of fever, tachycardia, and tachypnea suggests bronchitis instead of pneumonia, except in elderly patients