Chronic bronchitis

Chronic bronchitis
Classification and external resources
ICD-10	J42
ICD-9	491
MeSH	D029481

Chronic bronchitis is a chronic inflammation of the bronchi (medium-size airways) in the lungs. It is generally considered one of the two forms of chronic obstructive pulmonary disease (COPD).^[1] It is defined clinically as a persistent cough that produces sputum (phlegm) and mucus, for at least three months per year in two consecutive years.^[2]

Signs and symptoms

Bronchitis may be indicated by an expectorating cough (also known as a productive cough, i.e. one that produces sputum), shortness of breath (dyspnea) and wheezing. Occasionally chest pains, fever, and fatigue or malaise may also occur. Mucus is often green or yellowish green and also may be orange or pink, depending on the pathogen causing the inflammation.

Causes

Tobacco smoking is the most common cause.^[3] Pneumoconiosis and long-term fume inhalation are other causes.^[3] Allergies can also cause mucus hypersecretion, thus leading to symptoms similar to asthma or bronchitis.^{[citation needed]}

Diagnosis

A physical examination will often reveal diminished breath sounds, wheezing and prolonged expiration. Most doctors 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:

• Pulmonary Function Tests (PFT) (or spirometry) must be performed in all patients presenting with chronic cough. An FEV1/FVC ratio below 0.7 that is not fully reversible after bronchodilator therapy indicates the presence of COPD, that requires more aggressive therapy and carries a more severe prognosis than simple chronic bronchitis.
• A chest X-ray that reveals hyperinflation; collapse and consolidation of lung areas would support a diagnosis of pneumonia. Some conditions that predispose to bronchitis may be indicated by chest radiography.
• A sputum sample showing neutrophil granulocytes (inflammatory white blood cells) and culture showing that has pathogenic microorganisms such as Streptococcus spp.
• A blood test would indicate inflammation (as indicated by a raised white blood cell count and elevated C-reactive protein).
• Neutrophils infiltrate the lung tissue, aided by damage to the airways caused by irritation.
• Damage caused by irritation of the airways leads to inflammation and leads to neutrophils being present
• 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.
• High Resolution Computed Tomography (HRCT) — This is a special type of CT scan that provides your doctor with high-resolution images of your lungs. Having a HRCT is no different than having a regular CT scan; they both are performed on an open-air table and take only a few minutes.

Treatment

Smoking cessation is of benefit.

Antibiotics

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. For acute exacerbations of chronic bronchitis, if antibiotics are used, amoxicillin or doxycycline is recommended.^[4]

Bronchodilators

Ipratropium is an example of a bronchodilator that may be useful for people suffering from chronic obstructive pulmonary disease, such as chronic bronchitis.

Albuterol is also a common drug for this disease.

Acute exacerbations

Main article: Acute exacerbations of chronic bronchitis

Acute exacerbations of chronic bronchitis (AECB) are episodes of difficulty in breathing in a person with chronic bronchitis.^[5]

During AECB, breathing becomes much more difficult because of further narrowing of the airways, in addition to increased secretion of mucus, which often is thicker than usual.^[5]

Treatment of AECB may include:

• Cough suppressants^[5]
• Inhaled bronchodilators^[5][6]
• Antibiotics are used if a bacterial infection is the suspected cause.^[5] However, antibiotics will not treat exacerbations caused by viruses.^[5]
• Corticosteroids^[5][6]
• Theophylline^[5]
• Oxygen therapy^[5]

References

1. ^ Shaker SB, Dirksen A, Bach KS, Mortensen J (June 2007). "Imaging in chronic obstructive pulmonary disease". COPD 4 (2): 143–61. doi:10.1080/15412550701341277. PMID 17530508. http://www.informaworld.com/openurl?genre=article&doi=10.1080/15412550701341277&magic=pubmed. 
2. ^ "chronic bronchitis" at Dorland's Medical Dictionary
3. ^ ^{a b} MedlinePlus - Bronchitis
4. ^ Hueston WJ (March 1997). "Antibiotics: neither cost effective nor 'cough' effective". The Journal of Family Practice 44 (3): 261–5. PMID 9071245. 
5. ^ ^{a b c d e f g h i} medbroadcast.com > Acute Exacerbations of Chronic Bronchitis Retrieved on Mars 13, 2010
6. ^ ^{a b} Bach PB, Brown C, Gelfand SE, McCrory DC (2001). "Management of acute exacerbations of chronic obstructive pulmonary disease: a summary and appraisal of published evidence". Ann. Intern. Med. 134 (7): 600–20. PMID 11281745. 

External links

• About.com - Chronic Bronchitis
• NIH Medline Plus - Bronchitis
• Familydoctor.org - Chronic Bronchitis
• eMedicineHealth - Bronchitis