Figure A shows the location of the lungs and bronchial tubes. Figure B is an enlarged view of a normal bronchial tube. Figure C is an enlarged view of a bronchial tube with bronchitis.
|Classification and external resources|
Acute bronchitis, also known as a chest cold, is short term inflammation of the bronchi (large and medium-sized airways) of the lungs. The most common symptom is a cough. Other symptoms include coughing up mucus, wheezing, shortness of breath, fever, and chest discomfort. The infection may last from a few to ten days. The cough may persist for several weeks afterwards with the total duration of symptoms usually around three weeks. Some have symptoms for up to six weeks.
In more than 90% of cases the cause is a viral infection. These viruses may be spread through the air when people cough or by direct contact. Risk factors include exposure to tobacco smoke, dust, and other air pollution. A small number of cases are due to high levels of air pollution or bacteria such as Mycoplasma pneumoniae or Bordetella pertussis. Diagnosis is typically based on a persons signs and symptom. The color of the sputum does not indicate if the infection is viral or bacterial. Determining the underlying organism is typically not needed. Other causes of similar symptoms include asthma, pneumonia, bronchiolitis, bronchiectasis, and COPD. A chest X-ray may be useful to detect pneumonia.
Prevention is by not smoking and avoiding other lung irritants. Frequent hand washing may also be protective. Treatment of acute bronchitis typically involves rest, paracetamol (acetaminophen), and NSAIDs to help with the fever. Cough medicine has little support for its use and is not recommended in children less than six years of age. There is tentative evidence that salbutamol may be useful in those with wheezing; however, it may result in nervousness. Antibiotics should generally not be used. An exception is when acute bronchitis is due to pertussis. Tentative evidence supports honey and pelargonium to help with symptoms.
Acute bronchitis is one of the most common diseases. About 5% of adults are affected and about 6% of children have at least one episode a year. It occurs more often in the winter. More than 10 million people in the United States visit a doctor each year for this condition with about 70% receive antibiotics which are mostly not needed. There are efforts to decrease the use of antibiotics in acute bronchitis.
Signs and symptoms
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.
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.
- 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.
A variety of tests may be performed in patients presenting with cough and shortness of breath:
- A chest X-ray is useful to pick up pneumonia which is more common in those with a fever, fast heart rate, fast respiratory rate or who are old.
- A sputum sample showing neutrophil granulocytes (inflammatory white blood cells) and culture showing that has pathogenic microorganisms such as Streptococcus species
- A blood test would indicate inflammation (as indicated by a raised white blood cell count and elevated C-reactive protein).
Most cases are self-limited and resolve themselves in a few weeks.
Evidence does not support the general use of antibiotics in acute bronchitis. 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 and no change in longer term outcomes. Antibiotics use also leads to the promotion of antibiotic-resistant bacteria, which increase morbidity and mortality.
Acute bronchitis usually lasts a few days or weeks. 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.
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.
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.
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.
- "What Is Bronchitis?". August 4, 2011. Retrieved 1 April 2015.
- Albert, RH (1 December 2010). "Diagnosis and treatment of acute bronchitis.". American family physician 82 (11): 1345–50. PMID 21121518.
- Tackett, KL; Atkins, A (December 2012). "Evidence-based acute bronchitis therapy.". Journal of pharmacy practice 25 (6): 586–90. PMID 23076965.
- "What Causes Bronchitis?". August 4, 2011. Retrieved 1 April 2015.
- "How Is Bronchitis Diagnosed?". August 4, 2011. Retrieved 1 April 2015.
- Wenzel, RP; Fowler AA, 3rd (16 November 2006). "Clinical practice. Acute bronchitis.". The New England journal of medicine 355 (20): 2125–30. PMID 17108344.
- "How Can Bronchitis Be Prevented?". August 4, 2011. Retrieved 1 April 2015.
- "How Is Bronchitis Treated?". August 4, 2011. Retrieved 1 April 2015.
- Smith, SM; Schroeder, K; Fahey, T (24 November 2014). "Over-the-counter (OTC) medications for acute cough in children and adults in community settings.". The Cochrane database of systematic reviews 11: CD001831. PMID 25420096.
- Becker, LA; Hom, J; Villasis-Keever, M; van der Wouden, JC (6 July 2011). "Beta2-agonists for acute bronchitis.". The Cochrane database of systematic reviews (7): CD001726. PMID 21735384.
- Smith, SM; Fahey, T; Smucny, J; Becker, LA (1 March 2014). "Antibiotics for acute bronchitis.". The Cochrane database of systematic reviews 3: CD000245. PMID 24585130.
- Braman, SS (January 2006). "Chronic cough due to acute bronchitis: ACCP evidence-based clinical practice guidelines.". Chest 129 (1 Suppl): 95S–103S. PMID 16428698.
- Fleming, DM; Elliot, AJ (March 2007). "The management of acute bronchitis in children.". Expert opinion on pharmacotherapy 8 (4): 415–26. PMID 17309336.
- Foxwell, AR; Cripps, AW (2000). "Haemophilus influenzae oral vaccination against acute bronchitis.". The Cochrane database of systematic reviews (2): CD001958. PMID 10796676.
- Smith, SM; Smucny, J; Fahey, T. "Antibiotics for acute bronchitis.". JAMA 312 (24): 2678–9. doi:10.1001/jama.2014.12839. PMID 25536260.
- Hueston WJ (March 1997). "Antibiotics: neither cost effective nor 'cough' effective". The Journal of Family Practice 44 (3): 261–5. PMID 9071245.
- "Bronchitis". Mayo Foundation for Medical Education and Research. 2007-04-20. Retrieved 2008-05-30.
- 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.
|Wikisource has the text of the 1911 Encyclopædia Britannica article Bronchitis.|
- Acute Bronchitis FamilyDoctor.org (American Academy of Family Physicians)