Chronic Cough: A Primary Care Evaluation
A chronic cough can be quite irritating and stressful for a patient. Think about trying to be productive at home, school, work, or even trying to successfully rest and sleep when having a persistent cough.
Unfortunately, it can be just as stresseful for the clinician trying to find a cause and treat the underlying etiology. Today we will be tackling the topic of chronic cough and we'll share a systematic approach to evaluate these patients.
As Aakash covered in his video on acute bronchitis or pneumonia, an acute cough, caused by an etiology such as a viral upper respiratory infection, can last one to three weeks and is self-limited.
A subacute cough lasts from three to eight weeks in duration.
Finally, a chronic cough is one that persists longer than eight weeks in length.
Not only can a chronic cough be impairing to a patient’s quality of life, but it can lead to complications such as muscle pain, vomiting, rib fractures, fatigue, syncope, urinary incontinence, and depression. It also can lead to psychosocial difficulties such as embarrassment and negative consequences on social situations and encounters.1
Starting the Evaluation
The evaluation of a chronic cough should focus on potential triggers such as...
- ACE inhibitor use
- Smoking history
- Environmental exposures
These are just to name a few.
Your history should also evaluate and rule out any red flag symptoms such:
- Weight loss
- History of recurrent pneumonia
- Smoking history >20 pack-years
- Smoker that is over 45 years of age.1
A patient’s description of a cough including the quality, timing, or presence or absence of sputum should not determine your approach in the evaluation of a chronic cough. Unless a likely etiology is identified during the history and physical examination, a chest radiograph should be completed to rule out most infectious, inflammatory, and thoracic malignant pathologies.
Additional diagnostics should focus on the detection and treatment of the four most common causes of a chronic cough: upper airway cough syndrome, asthma, nonasthmatic eosinophilic bronchitis, and gastroesophageal/laryngopharyngeal reflux disease.
Regarding treatment, sequential or concomitant treatment of these common causes is still recommended.1 After the evaluation and empiric treatment of these common etiologies, less common etiologies of a chronic cough can be evaluated as below.
Upper airway cough syndrome
Upper airway cough syndrome (UACS), is more commonly known as postnasal drip syndrome, was founded as an umbrella diagnosis for multiple etiologies such as chronic sinusitis, allergic rhinitis, and nonallergic rhinitis that present with the common complaint of a cough lasting longer than eight weeks in patients.
UACS is the most common cause of chronic cough in adults. Associated symptoms may include sneezing, rhinorrhea, nasal stuffiness, itching, and postnasal drainage. Physical examination may reveal visible posterior nasal drainage, swollen boggy nasal turbinates, and posterior pharyngeal cobblestoning.
Initial treatment should be avoidance of triggering allergens if known. Otherwise, medication options such as decongestants combined with antihistamines, intranasal corticosteroids, nasal saline rinses, or nasal anticholinergics are treatment options.
If a patient in these instances is suspected to have chronic sinusitis, a CT scan of the sinuses or flexible nasolaryngoscopy should be completed. Sinus radiography is not recommended due to limited sensitivity.1
The prevalence of asthma in those patients with a chronic cough ranges from 24 to 29 percent of cases. It should be suspected in patients who have a cough with shortness of breath, wheezing, and chest tightness; however, cough may be the only presenting symptom in those patients who have cough variant asthma.
Diagnosis can be made with pulmonary function testing or spirometry. If this initial testing is negative, but your clinical suspicion is high, you can consider completing a bronchial challenge test (methacholine challenge testing). Last, but not least, you can choose to treat a patient’s suspected asthma, and if symptoms improve, this is diagnostic as well.
Treatment of asthma may include short-acting bronchodilators in addition to potential inhaled corticosteroid therapy, a long-acting bronchodilator with inhaled corticosteroid therapy, or leukotriene receptor antagonist therapy all can be useful.
For severe asthma cases or cases of asthma exacerbation, a five to ten-day course of prednisone 40 to 60 mg daily can be given if asthma is strongly suspected based upon a provider’s clinical suspicion.
COPD can be another etiology of a chronic cough in adult patients. Signs and symptoms may include cough, wheezing, and excess sputum production. Diagnosis can be made with pulmonary function testing. Treatment of exacerbation will be with inhaled short-acting bronchodilators with or without combined short-acting anticholinergics, along with oral corticosteroid therapy (prednisone 40 to 50 mg daily for five days), and antibiotics (ex. azithromycin or levofloxacin).
Once a patient is stable, short-acting bronchodilators can be used as needed, but maintenance therapy with a long-acting beta agonist and long-acting muscarinic antagonist should be instituted initially with the potential addition of inhaled corticosteroids based upon severity.
Nonasthmatic Eosinophilic Bronchitis
Nonasthmatic eosinophilic bronchitis often presents with patients having a chronic cough with no symptoms or findings of airway or airflow obstruction and/or a normal methacholine challenge testing.
Another lab finding may be eosinophil prevalence in sputum culture/bronchoalveolar lavage, or on bronchoscopic brushings.
This disease does not respond to inhaled bronchodilator therapy, but should respond to inhaled corticosteroid therapy. Other therapies include avoidance of triggers. Lastly, oral corticosteroids are rarely needed but can be indicated if high-dose inhaled corticosteroids are not effective in the treatment of disease.
Gastroesophageal Reflux Disease
The prevalence of GERD being the underlying etiology of a chronic cough is around 73 percent. Studies have shown a link between GERD and chronic cough; however, the pathophysiology and treatment are debated.1 Associated symptoms may include regurgitation, heartburn, hoarseness, acid brash taste, and globus sensation.
Regarding treatment, several uncontrolled trials have shown improvement of patient’s chronic cough with antacid therapy; however, more recent randomized controlled trials revealed no difference in patients who were on proton pump inhibitor therapy and those on placebo.1
Although there is this conflicting data as above, proton pump inhibitors are recommended universally for treatment of suspected GERD associated chronic cough for at least eight weeks duration, along with dietary changes, and weight loss. In addition to PPI therapy, H2RA therapy with medications such as ranitidine may be helpful as well.
If GERD symptoms are still persistent, further evaluation with pH testing or manometry can be completed, and evaluation for surgical treatment may be indicated.
A patient who has a persistent unexplained cough even after a treatment trial for the most common etiologies should be referred pulmonology or ENT for further evaluation.
Neuromodulator medications such as gabapentin and pregabalin can be trialed in these instances. These medications have been seen to provide some benefit in randomized trials for the treatment of suspected neurogenic cough.
The hypothesis behind neurogenic cough is that a refractory cough may be due to hypersensitivity of the cough reflex caused by peripheral (afferent limb of the cough reflex) and central mechanisms.
Gabapentin up to 1,800 mg daily was seen to improve symptoms within four weeks, and pregabalin, 300 mg daily in addition to speech therapy showed more improvement of symptoms in comparison to placebo and speech therapy, and speech therapy alone in trials.1
1. Am Fam Physician. Chronic Cough: Evaluation and Management. 2017;96(9):575-580.
2. UpToDate. Management of Acute Exacerbations of Asthma in Adults. Accessed: December 31, 2018.
3. UpToDate. Evaluation of Subacute and Chronic Cough in Adults. Accessed: December 31, 2018.
4. UpToDate. Treatment of Subacute and Chronic Cough in Adults. Accessed: December 31, 2018.