What is Bronchorrhea and What are Some of the Causes?

Definition and Causes of Bronchorrhea

man spitting phlegm into a tissue
What is bronchorrhea and what are the causes?. Istockphoto.com/Stock Photo©Dean Drobot

What is bronchorrhea and what are some possible causes?

Definition: Bronchorrhea

Bronchorrhea is defined as an excessive discharge of watery mucus from the lungs.

Bronchorrhea in Detail

Bronchorrhea is diagnosed when an individual produces more than 100 cc's (20 teaspoons) of thin mucus from their lungs daily. This is not just a little drainage, and can be an incredibly annoying symptom. This symptom tends to be at its worst in the morning and improve through the day.

Bronchorrhea is different than coughing up phlegm or sputum. It's thought to be due to the airways being "hyperresponsive" to a stressor. Unlike the airways being overly responsive as occurs with airway constriction such as asthma, this condition causes "secretory hyperresponsiveness."


There are several causes of bronchorrhea, though thankfully it is a fairly rare occurrence.

  • Lung cancer - A form of lung cancer which in the past was called mucinous bronchioloalveolar carcinoma (BAC), is the most common cause of bronchorrhea. BAC has been reclassified as a form of lung adenocarcinoma, but still causes this bothersome drainage for people living with the new diagnosis.
  • Chronic bronchitis - Chronic bronchitis is a form of chronic obstructive pulmonary disease (COPD) characterized by inflammation of the bronchi.
  • Asthma - especially cough variant asthma - Cough variant asthma is an atypical form of asthma in which the only symptom at the time of diagnosis is a cough.
  • Some poisonings - Particularly organophosphates (anticholinesterase pesticides).
  • Tuberculosis
  • Bronchiectasis - Bronchiectasis is a form of COPD often caused by childhood respiratory infections, which results in mucus collection in the airways due to widening and dilation of the airways.


While bronchorrhea is mostly a nuisance, and can be very dramatic, it may result in abnormalities in the body's electrolytes.

  When severe, it may also result in obstruction of the airways.


The best treatment for bronchorrhea is to find and treat the underlying cause, especially if this is lung cancer. Treatments that have been tried for the symptom alone include steroids and non-steroidal antiinflammatory inhalers, with only moderate relief at best.

Sometimes significant and very dramatic improvement has been noted with using the medications Tarceva and Iressa. These medications target an EGFR mutation present in some lung cancers. It's now felt that everyone diagnosed with lung adenocarcinoma, no matter the stage, should undergo genetic testing (molecular profiling) to check for the presence of treatable (targetable) mutations such as an EGFR mutations, ALK rearrangements, and ROS1 rearrangements.


Popat, N., Raghavan, N., and R. McIvor. Severe bronchorrhea in a patient with bronchioloalveolar carcinoma. Chest. 2012. 141(2):513-4.

Rubin, B., Priftis, K., Schmidt, H., and M. Henke. Secretory hyperresponsiveness and pulmonary mucus hypersecretion. Chest. 2014. 146(2):496-507.

Rogers, D. Physiology of airway mucus secretion and pathophysiology of hypersecretion. Respiratory Care. 2007. 52(9):1134-46.

Thotahil, Z., and J. Long. Erlotinib effective against refractory bronchorrhea from advanced non-small cell lung cancer. Journal of Thoracic Oncology. 2007. 2(9):881-2.

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