Reactive Airways Dysfunction Syndrome (RADS)

In your legal career, eventually you will come across RADS (Reactive Airways Dysfunction Syndrome), even in trucking litigation, particularly when hauling hazardous materials.
One of the oddest and difficult cases to defend in the trucking industry involved a person who claimed to have developed RADS from the leaking of hazardous chemicals in product delivered.
For a moment, disregard the issue of liability or if Carmack would apply to limit the personal injury damages from cargo delivered (see prior blogs on Carmack defenses). For now, let’s focus on the diagnoses and cause of RADS.
So what exactly do you know about RADS?

What is RADS?
There is disagreement as to the exact definition/nature of RADS. The term “Reactive Airways Dysfunction Syndrome” was first used by S.M. Brooks and his colleagues in a 1985 article in a magazine published y the American College of Chest Physicians (the article is attached). Brooks defined RADS as “an asthma-like illness [developed] after a single exposure to high levels of an irritating vapor, fume, or smoke.”
Over time, many in the medical community have begun to mistakenly use RADS as a synonym for asthma. There is agreement among the authors of the article I read that RADS is distinct from asthma.
How is RADS treated?
RADS may be treated with prescription medications or anti-inflammatory drugs. The research I conducted led to the conclusion that complete treatment of the disease is possible. Of course, treatment is only successful if the patient avoids continued exposure to the irritants that caused the disease.

How is RADS diagnosed?




  1. A documented absence of preceding respiratory complaints.
  2. The onset of symptoms occurred after a single specific exposure incident or accident.
  3. The exposure was to a gas, smoke, fume, or vapor which was present in very high concentrations and had irritant qualities to it in nature.
  4. The onset of symptoms occurred within 24 hours after the exposure and persisted for at least three months.
  5. Symptoms simulated asthma with cough, wheezing, and dyspnea predominating.
  6. Pulmonary function tests may show airflow obstruction.
  7. Methacholine challenge testing must be  positive.
  8. Other types of pulmonary diseases were ruled out.
  9. Doctors normally use a pulmonary function test and/or a bronchial challenge test to determine if a patient has RADS.

What causes RADS?

Exposure to external, respiratory irritants causes RADS. Such irritants include, but are not limited to the following: smoke, fire, gases, fumes, dust, uranium, hexafluoride, floor sealant, spray paint, certain concentration levels of hydrazine, heated acid vapors and fumes (as encountered in welding), fumigating fog, and metal coat remover.
In our case, Dr. Joseph Lasky was hired to render his opinion if  the  plaintiff had RADS. He stated, “The definition of RADS is not here. None of the pulmonary tests indicate RADS.”
Only indication of RADS was that a physician heard a soft wheezing.
Testing has not shown the criteria of RADS. Records show no obstruction, which is required for RADS.
Patient must make an effort if test is to be valid. To make sure it is valid, as patient must blow several times. If records only show one incident of blowing, then validity is suspect.
A pulmonologist who treated the plaintiff diagnosed him with RADS, but  diagnosis was based solely on the history given by the patient/plaintiff, but no methacholine challenge test was administered to verify this diagnosis.
Methacholine challenge test has not been performed. Such a test is the definitive test for RADS.

What is the effect of RADS?

Symptoms of reactive airway disease appear within the first 24 hours, after the exposure to the irritants. This is one of the basic distinguishing factor between RAD and asthma. If the symptoms appear after 24 hours, one cannot call it a reactive airway disease. This disease can be mild as well as severe, depending on the amount of irritant exposure. The irritants may cause the respiratory tract to swell and get inflamed. The symptoms of reactive airway disease are similar to that of asthma. For example, shortness of breath, wheezing and cough are the common symptoms of RAD. Due to the inflammation of the lungs, there is excess mucus production. Sometimes, excess and frequent exposure to respiratory irritants can make the condition chronic, which leads to further discomfort.






 Why Methacholine Test?
Dr. Lasky said that when a methacholine challenge test is performed, a valid test is performed and also a dummy test to test for faking.
Methacholine challenge test is the introduction of increasingly higher levels of a chemical. 20% is positive. Sensitivity at higher levels of methacholine may be caused by something other than RADS. Dr. Lasky states, “If the plaintiff has RADS, then he must show he has it, and nothing in his records shows that he has it.”
There can be false positive methacholine challenge tests, but there really cannot be false negatives. So, the plaintiff cannot say that RADS sometimes exists even when the methacholine challenge tests says he is negative.
There was a drop in numbers in the previous testing of the plaintiff. Dr. Lasky stated that the only rational reasons for this are 1) he was not trying, or 2) he was “pooped out.”


When deposing a someone alleging RADS, the following should be addressed:


1. False positive methacholine challenge test, such as congestive heart failure, history of asthma, other exposures.
2. Ask for any chest X-rays. I an abnormality is shown from  a high respiratory rate. This could be the beginning of lung problems, but also could be caused by other factors such as stress/excitement. Did the  plaintiff had a regular heart rate in the emergency room?
3. If all emergency room test were normal – normal chest x-rays, heart rate, blood tests, there  would not have been an reason to order  a pulmonary function study.
4. Even if  pulmonary tests administered, would the tests have changed condition/treatment? If a pulmonary function study had been given immediately, it just would have diagnosed lung problems earlier.
5.   If a patient had a lung injury/virus and had a pulmonary function study performed, the test may show a problem. One week later, such a test may be normal.
6. RADS will not go away in one week. Pulmonary function tests are not part of the diagnostic criteria for RADS. The failure to perform an earlier pulmonary function test has no bearing on whether the plaintiff has RADS.

7. Key symptoms of RADS: irritation of eyes, nose, throat. Need to ask plaintiff about whether he had eye irritation. Cannot get to lungs before getting ear, nose, throat, skin irritation. When you have ear, nose, throat, skin irritation, you usually get out of the area of exposure. He was not trapped.


8. Ask in deposition:

  • Was the workplace/area of exposure  ventilated?
  • How close was deponent to the material?
  • Get the exact temporal relationship between exposure and onset of   symptoms?
  • When did he first have respiratory symptoms? Pin this down
  •  RADS simulates asthma within 24 hours of exposure


RADS requires a massive, high level exposure. RADS is normally associated with “exposure frequently associated with explosions.” He would be surprised if a small amount of chemical leaking out of drums would be sufficient to cause RADS.
Certain chemicals with high vapor pressure can cause smell; however, he cautions that just because a chemical gets in one’s nostrils does not mean it will get to one’s lungs.


These are just a few preliminary thoughts on the issue of RADS. Do NOT get sucked in (pun intended) to the diagnosis of RADS. Although the risks are HIGH if a claimant has the disease, properly diagnosing the disease takes a careful Daubert analysis. Don’t be timid in questioning the diagnosis.

As always, if there is more you would like to know about this issue or other issues affecting the trucking industry or in the defense of trucking/commercial interests, don’t hesitate to call.
Mark Perkins
Perkins & Associates, LLC

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