ACOS: Asthma Chronic Obstructive Pulmonary Disease Overlap Syndrome

When Asthma and COPD Occur Together

COPD VS Asthma: Which Is it?
COPD VS Asthma: Which Is it?. Photo © Photodisc

Asthma and chronic obstructive pulmonary disease (COPD) are chronic diseases of the airways that both have obstruction, inflammation, and airway hyperresponsiveness as part of the disease process.

In asthma obstruction is intermittent, reversible, and lung function returns to normal. On the other hand, obstruction in COPD is irreversible and often progressive.

Asthma is typically thought of as an allergic childhood disease and COPD is though to develop in later life as a result of smoking.

While normally considered separate diseases, there are some people that have an overlap syndrome known as ACOS or asthma chronic cbstructive pulmonary disease. Overlap Syndrome. The overlap is more common as patients get older.

The “Dutch hypothesis” states that asthma and airway hyperresponsiveness predispose patients to COPD later in life. The hypothesis further posits that asthma, COPD, chronic bronchitis, and emphysema are just different points on one disease spectrum.

Overlap Syndrome Criteria

Diagnosing overlap syndrome can be difficult because most asthma studies exclude COPD patients and COPD studies exclude asthma patients. Experts also do not agree on the diagnostic criteria, but consider the following in making a diagnosis:

  • A physician diagnosis of asthma and COPD in the same patient
  • History or evidence of atopy such as:
  • Smoking history of more than 10 pack-years
  • Postbronchodilator FEV1 <80% predicted
  • FEV1/FVC ratio of less than 70%
  • Improvement of FEV1 and peak flows following bronchodilator
  • Eosinophila in the sputum

Treatment of ACOS

If your physician believes that you have ACOS, they do not have much in the way of guidance as there is no randomized clinical trial data to help guide therapeutic interventions in ACOS.

However, your doctor will likely follow general treatment guidelines geared towards reversing airflow obstruction.

If you continue to smoke, smoking cessation is an important goal to decrease wheezing, chest tightness, cough and shortness of breath.

Medical treatments for ACOS, like for asthma and COPD include:

  • Short acting bronchodilators or SABAs- Patients with both asthma and COPD are given treatment with bronchodilators and treatment is continued with symptomatic improvement. SABAs are used for the treatment of acute symptoms.
  • Long acting bronchodilators or LABAs- LABAs are used effectively as mono therapy in COPD, but not in the treatment of asthma due to the beneficial impact of inhaled steroids.
  • Anticholinergics- In COPD, anticholinergic drugs provide equivalent bronchodilation compared to beta agonists. The recipe for bronchodilation in COPD will depend on how you respond to each medicine individually or in combination.
  • Inhaled steroids- Inflammation is asthma is from eosinophils](http://asthma.about.com/od/glossary/g/def_eosinophil.htm) while inflammation from COPD is from neutrophils. In asthma inhaled steroids are used earlier than in COPD.
  • Systemic steroids
  • Antibiotics- for moderate to severe COPD exacerbations. Antibiotics are not routinely recommended as most respiratory infections are viral.

When your doctor suspects some overlap between asthma and COPD, your evaluation and treatment will likely seem like a mixture of both.

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Sources

  1. N. G. M. Orie. The Dutch Hypothesis
    . Accessed on July 18, 2015.
  2. National Heart, Lung, and Blood Institute. Expert Panel Report 3 (EPR3): Guidelines for the Diagnosis and Management of Asthma. Accessed on July 18, 2015.
  3. Papaiwannou A et al. Asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS): current literature review.. J Thorac Dis. 2014 Mar; 6(Suppl 1): S146–S151. Accessed on July 18, 2015.

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