In some patients, chronic coughing may be the source of major suffering. Chronic cough can cause pain, interfere with sleep, aggravate dyspnea, and worsen fatigue. The causes of cough can be classified much like the causes of dyspnea.
One approach to chronic cough in palliative care patients is to consider the differential diagnoses summarized below:
- Malignancy-related causes of cough, e.g., direct irritation by the presence of a tumor or tracheo-esophageal fistula.
- Drug-related cough: rule out cough induced by medications such as angiotensin-converting enzyme inhibitors.
- Other noncancer causes of cough: rule out asthma, chronic obstructive pulmonary disease, reflux issues, and chronic heart failure.
The optimal therapy for chronic cough is treatment of the underlying disorder, such as:
- Radiation therapy for the underlying endobronchial tumor mass irritating the airway.
- Stenting of tracheo-esophageal fistula.
- Drainage of a pleural effusion.
- Corticosteroids for lymphangitic carcinomatosis.
Cough-suppressing agents such as opioids are commonly utilized. Anecdotal evidence suggests a role for inhaled local anesthetics, which should be utilized judiciously and sparingly; they are unpleasant to the taste and obtund the gag reflex, and anaphylactic reactions to preservatives in these solutions have been documented. Opioid and nonopioid antitussives, such as dextromethorphan, may act synergistically, but further studies are required to confirm this hypothesis. Gabapentin was found to be efficacious compared with placebo for chronic refractory cough, although this study did not specifically include cancer patients.
In cases of increased sputum production, expectorants and mucolytics have been employed, but the effects have not been well evaluated. Inhaled sodium cromoglycate has shown promise as a safe method of controlling chronic coughing related to lung cancer.References
- Dudgeon DJ, Rosenthal S: Management of dyspnea and cough in patients with cancer. Hematol Oncol Clin North Am 10 (1): 157-71, 1996. [PUBMED Abstract]
- Ryan NM, Birring SS, Gibson PG: Gabapentin for refractory chronic cough: a randomised, double-blind, placebo-controlled trial. Lancet 380 (9853): 1583-9, 2012. [PUBMED Abstract]
- Moroni M, Porta C, Gualtieri G, et al.: Inhaled sodium cromoglycate to treat cough in advanced lung cancer patients. Br J Cancer 74 (2): 309-11, 1996. [PUBMED Abstract]