Acute bronchitis

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Acute Bronchitis
This image shows the consequences of acute bronchitis.
Classification and external resources
ICD-10 J20-J21
ICD-9 466
MedlinePlus 001087
eMedicine article/297108
MeSH D001991

Acute bronchitis or chest cold is an inflammation of the large bronchi (medium-size airways) in the lungs that is usually caused by viruses or bacteria and may last several days or weeks.[1] Characteristic symptoms include cough, sputum (phlegm) production, and shortness of breath and wheezing related to the obstruction of the inflamed airways. Diagnosis is by clinical examination and sometimes microbiological examination of the phlegm. Treatment for acute bronchitis is typically symptomatic. As viruses cause most cases of acute bronchitis, antibiotics should not be used unless microscopic examination of gram-stained sputum reveals large numbers of bacteria.

Signs and symptoms[edit]

Bronchitis may be indicated by an expectorating cough, shortness of breath (dyspnea), and wheezing. On occasion, chest pains, fever, and fatigue or malaise may also occur. In addition, bronchitis caused by Adenoviridae may cause systemic and gastrointestinal symptoms as well. However, the coughs due to bronchitis can continue for up to three weeks or more even after all other symptoms have subsided.[citation needed]


Acute bronchitis can be caused by contagious pathogens, most commonly viruses. Typical viruses include respiratory syncytial virus, rhinovirus, influenza, and others. Bacteria are uncommon pathogens but may include Mycoplasma pneumoniae, Chlamydophila pneumoniae, Bordetella pertussis, Streptococcus pneumoniae, and Haemophilus influenzae.[citation needed]

  • Damage caused by irritation of the airways leads to inflammation and leads to neutrophils infiltrating the lung tissue.
  • Mucosal hypersecretion is promoted by a substance released by neutrophils.
  • Further obstruction to the airways is caused by more goblet cells in the small airways. This is typical of chronic bronchitis.
  • Although infection is not the reason or cause of chronic bronchitis, it is seen to aid in sustaining the bronchitis.


A physical examination will often reveal decreased intensity of breath sounds, wheezing, rhonchi, and prolonged expiration. Most physicians rely on the presence of a persistent dry or wet cough as evidence of bronchitis.[citation needed]

A variety of tests may be performed in patients presenting with cough and shortness of breath:[citation needed]


In 1985, University of Newcastle, Australia Professor Robert Clancy developed an oral vaccine for Haemophilus influenza. This vaccine was commercialised four years later.[2]



Only about 5-10% of bronchitis cases are caused by a bacterial infection. Most cases of bronchitis are caused by a viral infection and are self-limited and resolve themselves in a few weeks. Acute bronchitis should not be treated with antibiotics unless microscopic examination of the sputum reveals large numbers of bacteria. While antibiotics speed up resolution of the cough by about 12 hours there is a greater risk of gastrointestinal problems.[3] Antibiotics use also leads to the promotion of antibiotic-resistant bacteria, which increase morbidity and mortality.[4]

Smoking cessation[edit]

For more details on this topic, see Smoking cessation.

Many physicians recommend that, to help the bronchial tree heal faster and not make bronchitis worse, smokers should quit smoking completely in order to allow their lungs to recover from the layer of tar that builds up over time.[citation needed]


Acute bronchitis usually lasts a few days or weeks.[5] It may accompany or closely follow a cold or the flu, or may occur on its own. Bronchitis usually begins with a dry cough, including waking the sufferer at night. After a few days, it progresses to a wetter or productive cough, which may be accompanied by fever, fatigue, and headache. The fever, fatigue, and malaise may last only a few days; but the wet cough may last up to several weeks.[citation needed]

Should the cough last longer than a month, some physicians may issue a referral to an otorhinolaryngologist (ear, nose and throat doctor) to see if a condition other than bronchitis is causing the irritation. It is possible that having irritated bronchial tubes for as long as a few months may inspire asthmatic conditions in some patients.[citation needed]

In addition, if one starts coughing mucus tinged with blood, one should see a physician. In rare cases, physicians may conduct tests to see whether the cause of the bloody sputum is a serious condition such as tuberculosis or lung cancer.[citation needed]


In infants under one year of age, acute bronchitis was the most common reason for admission to the hospital after an emergency department visit in the US in 2011.[6]


  1. ^ Wenzel RP, Fowler AA (2006). "Clinical practice. Acute bronchitis". N. Engl. J. Med. 355 (20): 2125–30. doi:10.1056/NEJMcp061493. PMID 17108344. 
  2. ^ Clancy RL, Cripps AW, Gebski V (Apr 1990). "Protection against recurrent acute bronchitis after oral immunization with killed Haemophilus influenzae". Med J Aust. 152 (8): 413–6. PMID 2184330. 
  3. ^ Smith, SM; Smucny, J; Fahey, T. "Antibiotics for acute bronchitis.". JAMA 312 (24): 2678–9. PMID 25536260. 
  4. ^ Hueston WJ (March 1997). "Antibiotics: neither cost effective nor 'cough' effective". The Journal of Family Practice 44 (3): 261–5. PMID 9071245. 
  5. ^ "Bronchitis". Mayo Foundation for Medical Education and Research. 2007-04-20. Retrieved 2008-05-30. 
  6. ^ Weiss AJ, Wier LM, Stocks C, Blanchard J (June 2014). "Overview of Emergency Department Visits in the United States, 2011". HCUP Statistical Brief #174. Rockville, MD: Agency for Healthcare Research and Quality. 

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