Acute bronchitis

 

Acute Bronchitis

Summary / Definiton

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. 

Sign & Symptoms

Common symptoms of acute bronchitis include:

• a cough, which may continue beyond 10 days and contain clear or colored mucus
• shortness of breath
• wheezing
• a low-grade fever or a high fever may be an indication of a secondary infection such as pneumonia
• chest pain
• chest tightness
• a sore throat from persistent coughing

Children with acute bronchitis may experience:

• a runny nose
• chills
• back pain
• muscle pain
• a sore throat

If you experience any of the following symptoms, call your doctor:

• unexplained weight loss
• a deep, barking cough
• difficulty breathing
• chest pain
• a fever of 100.4°F (38°C) or higher
• a cough that last more than 10 days

Causes

• 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

Diagnosis

• 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 exclude 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).

Complications

Although a single episode of bronchitis usually isn't cause for concern, it can lead to pneumonia in some people. Repeated bouts of bronchitis may indicate that you're developing chronic obstructive pulmonary disease (COPD).

Treatment

Most cases of acute bronchitis resolve without medical treatment in two weeks.

Medications
In some circumstances, your doctor may prescribe medications, including:

• Antibiotics. Bronchitis usually results from a viral infection, so antibiotics aren't effective. However, your doctor might prescribe an antibiotic if he or she suspects that you have a bacterial infection.
• Cough medicine. It's best not to suppress a cough that brings up mucus, because coughing helps remove irritants from your lungs and air passages. If your cough keeps you from sleeping, you might try cough suppressants at bedtime.
• Other medications. If you have allergies, asthma or chronic obstructive pulmonary disease (COPD), your doctor may recommend an inhaler and other medications to reduce inflammation and open narrowed passages in your lungs.

Therapies

• If you have chronic bronchitis, you may benefit from pulmonary rehabilitation — a breathing exercise program in which a respiratory therapist teaches you how to breathe more easily and increase your ability to exercise.

Prevention

An oral whole cell nontypeable Haemophilus influenzae vaccine may protect against the disease.

Prognosis

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

Epidemiology

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. 
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.