A Brief Synopsis of AFP's "Evaluation of the Patient with Chronic Cough"

A Brief Synopsis of:
Evaluation of the Patient with Chronic Cough
JOSEPH J. BENICH III, MD, and PETER J. CAREK, MD, MS, Medical University of South Carolina, 
Charleston, South Carolina
Am Fam Physician. 2011 Oct 15;84(8):887-892
http://www.aafp.org/afp/2011/1015/p887.pdf

     Cough is a protective reflex to clear the upper airways. If the cough has been going on for 3 weeks, then it is classified as acute. It is most often due to a viral infection, asthma, COPD, irritant exposure, or an underlying cardiopulmonary issue. Cough that last 3-8 weeks is considered subacute. It is usually due to a post infectious cause or asthma.  Anything longer is considered chronic. Chronic cough is most likely from GERD, asthma, ACEIs, URI/LRI or upper airway cough syndrome (UACS). Often times there are multiple causes going on at the same time.
     Evaluation of chronic cough starts with a history and exam. Patients who are smokers or on ACEIs should stop using them and see if the cough stops. The next step is to x ray the lungs to rule out bronchiectasis, pneumonia, sarcoidosis, and TB. Sputum tests, PFTs, CT, esophagography, bronchoscopy, and cardiac studies should also be done and results should be evaluated for treatment.
     If at this point the cause of the cough is still a mystery, the patient should be evaluated for UACS, asthma, and GERD. UACS is the most common cause of chronic cough in nonsmokers with normal x rays. Patients will present with nasal discharge, drainage in the the posterior pharynx, cobblestoning of the oropharyngeal mucosa, and mucus in the oropharynx. Patients will respond to decongestants and H1 blockers. Resolution of cough after treatment reinforces a correct diagnosis. Patient who do not respond to treatment but are still thought to have USCS may undergo sinus imaging.
     Asthma can present with cough (especially in "cough -variant asthma"!).Symptoms can be made worse with cold, exercise, or during the night. Asthma can be diagnosed with spirometry and methocholine challenge.
     GERD can cause coughing when the acid reflux irritates the upper airway and stimulates the esophageal cough reflex. Diagnosis can be confirmed with resolution from a PPI. Esophageal pH monitoring can also be done.
     ACEIs can cause cough in 5-20% of patients. It could occur after a week of using the medication, or it could take 6 months to show signs of cough. Resolution should occur after a few days to several weeks after discontinuation of the ACEI. ARBs can be used instead.
     Some uncommon causes of cough include nonasthmatic eosinophilic bronchitis, postinfectious cough, and chemical irritants These causes would have a negative x ray result. Nonasthmatic eosinophilic bronchitis will  have normal airway hyperresonance, eosinophilic sputum, normal spirometry, and a positive response from corticosteroids. Postinfectious cough should resolve on its own. Chemical irritants should be removed from the environment.
     Bronchiectasis can cause cough and the x ray would show bronchial wall thickening. It can be associated with infection, CF, aspiration among others. Bronchogenic carcinoma, TB and sarcoidosis will have specific radiological and laboratory findings. In children, it is important to also consider aspiration, pertussis, and congenital abnormalities in the differential diagnosis.