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Chronic Cough Workup, Part III
Eosinophilic bronchitis (EB) is an airway inflammation affecting all sizes of airways, which causes a chronic cough, but no wheezing. It is distinguished from asthma and cough variant asthma by normal spirometry tests (always) and a negative inhalation challenge test , although sputum tests and eNO demonstrate an eosinophilic airway inflammation. Cough reflex sensitivity is normal in patients with EB.
Inhaled corticosteroids effectively suppress the superficial airway inflammation of EB, but unlike typical asthma, bronchodilators such as Albuterol are not helpful (because such patients have no bronchoconstriction). About 20% of patients with EB develop asthma over the years, but this risk may be reduced by inhaled corticosteroid therapy. In others, the EB just resolves by itself.
Atopic cough is a category recently proposed by Japanese investigators. It has all the features of EB except that cough reflex sensitivity (CRS) is abnormally high and antihistamine therapy is usually successful (as with allergic rhinitis), but there is no evidence of allergic rhinitis (hayfever).
Sino-bronchial syndrome (SBS) is a new name for rhinitis causing sinusitis which causes post-nasal drainage (PND) which leads to chronic throat-clearing and cough. Sinusitis can be confirmed by a sinus CT scan, but PND and sinusitis symptoms are usually enough evidence to confirm sinusitis. Many such patients have allergies which affect their nose, but no lower airway inflammation (thus spirometry, MCT, and sputum eosinophil levels are normal). The cough reflex is usually normal. The usual sinusitis treatments are usually beneficial, and chronic erythromycin therapy usually eliminates the chronic cough.
GERD (gastro-esophageal reflux disease) can cause a chronic cough and is increasingly common as people gain weight, but also occurs in thin people and may not cause the classic symptom of heartburn after eating a heavy or spicy meal. The gold standard test for GERD uses a 24 hour esophageal pH probe, but this is expensive and poorly accepted by many patients, so GERD is usually ruled out as the cause of a chronic cough by a 3-6 month trial of a proton pump inhibitor pill (PPI, which eliminates gastric acid production).
Chronic idiopathic cough (CIC) is a category proposed by British investigators in 2005. Idiopathic means that all other causes of a chronic cough have been ruled out, so doctors don't know what's causing it. Such patients have an increased cough reflex sensitivity, as measured by inhalation of increasing concentrations of capsaicin. None of the other tests mentioned above are abnormal. Capsaicin is the "spice" or heat from chili peppers and the principal ingredient of Mace, but the CRS test uses low concentrations and is very safe and well-tolerated by patients. The onset of the chronic cough of CIC is often with a upper respiratory viral infection (URI), but the post viral URI cough of most people resolves within a few days or weeks. Interestingly, the only abnormal test of those with multiple chemical sensitivity is also cough reflex sensitivity.
Chronic Cough Workup, Part I
Chronic Cough Workup, Part II
Related Topics: Asthma Complexities, Coughs: Home Remedies
Inhaled corticosteroids effectively suppress the superficial airway inflammation of EB, but unlike typical asthma, bronchodilators such as Albuterol are not helpful (because such patients have no bronchoconstriction). About 20% of patients with EB develop asthma over the years, but this risk may be reduced by inhaled corticosteroid therapy. In others, the EB just resolves by itself.
Atopic cough is a category recently proposed by Japanese investigators. It has all the features of EB except that cough reflex sensitivity (CRS) is abnormally high and antihistamine therapy is usually successful (as with allergic rhinitis), but there is no evidence of allergic rhinitis (hayfever).
Sino-bronchial syndrome (SBS) is a new name for rhinitis causing sinusitis which causes post-nasal drainage (PND) which leads to chronic throat-clearing and cough. Sinusitis can be confirmed by a sinus CT scan, but PND and sinusitis symptoms are usually enough evidence to confirm sinusitis. Many such patients have allergies which affect their nose, but no lower airway inflammation (thus spirometry, MCT, and sputum eosinophil levels are normal). The cough reflex is usually normal. The usual sinusitis treatments are usually beneficial, and chronic erythromycin therapy usually eliminates the chronic cough.
GERD (gastro-esophageal reflux disease) can cause a chronic cough and is increasingly common as people gain weight, but also occurs in thin people and may not cause the classic symptom of heartburn after eating a heavy or spicy meal. The gold standard test for GERD uses a 24 hour esophageal pH probe, but this is expensive and poorly accepted by many patients, so GERD is usually ruled out as the cause of a chronic cough by a 3-6 month trial of a proton pump inhibitor pill (PPI, which eliminates gastric acid production).
Chronic idiopathic cough (CIC) is a category proposed by British investigators in 2005. Idiopathic means that all other causes of a chronic cough have been ruled out, so doctors don't know what's causing it. Such patients have an increased cough reflex sensitivity, as measured by inhalation of increasing concentrations of capsaicin. None of the other tests mentioned above are abnormal. Capsaicin is the "spice" or heat from chili peppers and the principal ingredient of Mace, but the CRS test uses low concentrations and is very safe and well-tolerated by patients. The onset of the chronic cough of CIC is often with a upper respiratory viral infection (URI), but the post viral URI cough of most people resolves within a few days or weeks. Interestingly, the only abnormal test of those with multiple chemical sensitivity is also cough reflex sensitivity.
Chronic Cough Workup, Part I
Chronic Cough Workup, Part II
Related Topics: Asthma Complexities, Coughs: Home Remedies
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