Bronchitis

Bronchitis Main page
Patient Information
Overview
Causes
Classification Acute bronchitis Chronic bronchitis
Differential Diagnosis

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]
Synonyms and keywords: Inflammation of bronchus

Overview

Bronchitis is an inflammation of the bronchi (medium and large size airways). Acute bronchitis is a self-limiting disease usually caused by viruses or bacteria. Chronic bronchitis is a subtype of the chronic obstructive pulmonary disease (COPD), and it is defined as a chronic productive cough for at least three months in two consecutive years, after excluding other causes of chronic cough. The inflammatory response of the bronchial epithelium to infections or irritants that involve the medium and large-sized airways results in thickening of the bronchial and tracheal mucosa. Hallmark features of the pathophysiology of chronic bronchitis include hyperplasia and hypertrophy of the goblet cells of the airway, resulting in an increased mucus secretion, which contributes to the airway obstruction. Microscopically, there is infiltration of the walls of the airway with inflammatory cells, particularly neutrophils. Inflammation is followed by scarring and remodeling that thickens the walls, resulting in narrowing of the small airway. Further progression leads to metaplasia and fibrosis of the lower airway. The consequence of these changes is a limitation of airflow. Acute bronchitis affects young children and old people. Its overall incidence is approximately 5% in the U.S. There is no racial or gender predilection for this disease.Although chronic bronchitis is common among geriatric patients, it occurs more commonly among caucasian individuals compared to other races, and there is no sexual predilection. Age, season of the year and the immunization status are the main determining risk factors for acquiring acute bronchitis. The most potent risk factor in the development of chronic bronchitis is cigarette smoking. Other risk factors are occupational pollutants such as cadmium and silica, air pollutants, and genetic factors such as alpha 1 antitrypsin deficiency Acute bronchitis is a self limiting lower respiratory tract infection that usually presents with cough that lasts for up to 3 weeks. Chronic bronchitis gradually worsens over time and can result in death. The rate of deterioration varies between individuals and depends on the level of airflow obstruction. The prognosis is dependent on early recognition and smoking cessation, which improves the outcome significantly. Smoking cessation, good hand hygiene, vaccination, and a reduction in occupational exposure to known risk factors, are important to ensure decreased severity and risk of bronchitis.

Causes

• Acute Bronchitis: may be caused by either viruses, bacteria or environmental factors.

Viruses: Influenza virus, parainfluenza virus, respiratory syncytial virus, coronavirus, adenovirus, enterovirus, rhinovirus, coxsackievirus, and human metapneumovirus

Bacteria: Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Bordetella pertussis

Environmental factors: Toxic fume inhalation, tobacco, dust, and aerosols

• Chronic Bronchitis: may be caused by smoking, air pollutants and occupational exposures in a genetically susceptible person.

Classification

Bronchitis is classified into two major categories based on symptom chronicity:

• Acute bronchitis
• Chronic bronchitis

Differential diagnosis

Organ System	Disease	Symptoms	Signs	Laboratory findings	Diagnostic modality	Management
Cardiac	HFpEF	Exertional dyspnea, reduced exercise tolerance, orthopnea, paroxysmal nocturnal dyspnea, edema	Elevated JVP, fine crackles, edema	Increased BNP	Echocardiography (normal EF)	Control of volume overload and hypertension, treatment of underlying condition (obesity, AF, coronary artery disease, anemia)
	HFrEF	Exertional dyspnea, reduced exercise tolerance, orthopnea, paroxysmal nocturnal dyspnea, edema	Elevated JVP, fine crackles, edema	Increased BNP	Echocardiography (reduced EF)	Diuretics, ACE inhibitors, ARBs, beta blockers, nitrates
	Pericardial disease	Exercise intolerance, dyspnea, fatigue	Elevated JVP, pericardial knock, kussmaul's sign, pulsus paradoxus	-	Echocardiography, ECG	Diuretics, pericardiectomy
	Hypertrophic cardiomyopathy	Dyspnea, chest pain, palpitation, lightheadedness	Systolic murmur	-	Echocardiography, ECG	Beta blockers, verapamil
	Valvular disease (MR, TR)	Edema, fatigue, exercise intolerance, dyspnea, lightheadedness	Cardiac murmur	-	Echocardiography, ECG	Valve repair or replacement, diuretics, beta blockers
Pulmonary	Chronic airway disease	Cough, dyspnea, chest pain, exercise intolerance	Tachypnea, respiratory distress, cyanosis, edema, rhonchi and crackles	Hypoxemia, hypercapnea, polycythemia,	PFT, chest imaging	Bronchodilators, corticosteroids, anticholinergics
	Interstitial lung diseaee	Exercise intolerance, cough	Crackles, clubbing, cyanosis	Hypoxemia	PFT, Chest imaging, lung biopsy	Corticosteroids, bronchodilators
	Pulmonary hypertension	Dyspnea, fatigue, chest pain, syncope, palpitation	Edema, clubbing, elevated JVP, TR murmur	Elevated BNP, elevated d-dimer	Echocardiography, cardiac cathaterization	Diuretics, calcium channel blockers, endothelin receptor antagonist, phosphodiesterase 5 inhibitor
	Sleep apnea	Snoring, somnolence, headache, fatigue, irritability	Tachypnea, hypertension, tachycardia	Hypoxemia, polycythemia	Polysomnography	Weight reduction, CPAP
	Asthma	Dry cough, dyspnea, wheezing	Wheezing, tachypnea	Hypoxemia	PFT	Bronchodilators, corticosteroids, anticholinergics