The Appeal CommissionThe Workers Compensation Act of Manitoba

As the crux of this appeal lies in the comparative analysis of the worker’s asthma condition before and after his December 8, 2004 asthma attack, it is necessary to examine the medical reports and tests before and after his compensable injury.

The Pre-Existing Condition

The worker has had asthma since a very young age. A medical report dated January 4, 2005 indicates that he had almost daily problems with shortness of breath, coughing and wheezing. Medical records from 1995 to 2004 document regular visits to his family physician for his asthma condition as well as several periods of hospitalization in 1995, 1996, 1997, 1998 and 2000. Between 2001 and 2003 the worker’s asthma condition appeared to stabilize somewhat and he was able to remain out of the hospital. That said, a December 8, 2004 medical report from the worker’s treating internal specialist does comment that the worker was on a combination of medication including Ventolin up to 5 to 6 times daily that did not adequately control his asthma.

There are no records of lung capacity examinations prior to 2004 though the worker did testify to having had one in 1992 that was measured at approximately 96%.

Medical records for the fall of 2004 reveal that the worker went to the hospital for medical treatment for his asthma on six occasions between September and November 2004.

- September 30, 2004: complained of breathing difficulties which began one week before. At that time he was still smoking ½ pack of cigarettes a day;

- October 1, 2004: smoker trying to quit; diagnosis – rhinitis, poorly controlled asthma;

- November 19, 2004: peak flow – 245 before treatment, after treatment 325 – It is noted that he had a viral illness the week before and his asthma was triggered by grain dust;

- November 28, 2004: x-ray shows clear lungs, peak flows were at 295 before treatment and 315 after treatment;

- November 29, 2004: “major asthma exacerbation last few weeks. Took course of prednisone much improved following course which ended Wednesday November 24. Breathing gradually deteriorated November 27 – 28…” Peak flows were at 380 before treatment, 690 after treatment;

- November 30, 2004: the worker returned to the hospital for further treatment.

In addition to his asthma, the worker also suffers from rhinitis and allergies to the environment including grass, weeds, feathers, cats, dust mites, molds, pollens, dust, the main trigger being grain dust and smoking. The worker was also a smoker for many years but quit in late 2004.

The December 8, 2004 Compensable Injury

The worker was employed as a service technician for the accident employer since approximately 1995. His duties included cleaning combines. Though this was historically done with water, the employer changed the technique to pressurized air cleaning on September 30, 2004. The worker says that this new technique caused more dust in the air that caused him increased asthma attacks.

A December 8, 2004 hospital record comments on the worker’s progression of symptoms:

“The patient has been having difficulty with his asthma over the past two to three weeks. The illness started with a sore, scratchy throat and then worsening shortness of breath…Two months prior he had had quite a bad cold. He also quit smoking a month ago. He had a course of Prednisone for one week about three weeks ago and had felt quite a bit better, but after a few days of being off the Prednisone he started to get quite short of breath again. He was given another course for ten days and he has a few more days left in that course of 30 mg per day. Last night he felt very short of breath and this morning was at work…when he developed severe shortness of breath and had to be brought to us by ambulance…he fixes combines…and is exposed to a lot of grain dust in his job. He uses a filter mask consistently. This is his worst ever asthma exacerbation.”

A second hospital report of same date, which is authored by an internal specialist comments on the worker’s history and the trigger for the December 8, 2004 asthma attack:

“…[The worker has] a longstanding history of poorly controlled asthma…It doesn’t sound like even this combination [of medication] was controlling him adequately… At present it’s not clear what is triggering his asthma. Impression: Poorly controlled asthma, life-long in duration. No doubt, part of this poor control is contributed to by the fact that this man was a smoker for many years, he only quit two months ago I think when his health deteriorated. Also contributory is the fact that he works as an agricultural mechanic and can’t but help being exposed to grain dust to which he is allergic. It’s not certain to me whether the household dog, flowering house plants or any feather bedding are contributory, no doubt the rhinitis is a problem, as is the acid reflux.”

The worker remained in the hospital until December 21, 2004. The discharge summary reads:

“[The worker] is a known asthmatic patient that was admitted on December 8^th…with exacerbation of his asthma and a history of long term neglect and poor control of his asthma…[he] made a gradual recovery in hospital, continually improving on medication, and on the day of discharge his peak flow was running around 400 litres/minute. Lung function shows that his FEV1 is still below normal with a reading of 2.81, and a predicted normal of 4.4.”

Asthma Condition after December 28, 2004

Medical tests, reports and chart notes after December 28, 2004 reveal that the worker remained relatively stable with mild to moderate airflow limitation that hovered around 60%.

Chest x-rays done in May 2005 revealed linear scarring in the lower lobe likely on the right side with no acute pulmonary abnormality. However, a subsequent x-ray in September 2005 revealed very minor residual increased linear markings in the left lower lobe, suggesting slight scarring or residual atelectasis. It was noted at the time that this was a definite improvement since May 2005 with minor residual linear markings in the left lower lobe.

Family physician chart notes after December 28, 2004 document peak flow levels and subsequent asthma attacks:

- January 5, 2005: Peak flows between 380 and 500;

- January 17, 2005: peak flows went up after discharge from hospital to around 450. Now went down to 320. Diagnosis at the time was acute sinusitis with exacerbation of asthma;

- February 11, 2005: asthma not well controlled. Peak flows still below 500 (around 420 or 430). Letter given to book off work until April 15;

- April 6, 2005: had been doing fairly well until 3 weeks ago when he suffered an exacerbation of symptoms. Peak flow dropped to around low 300s;

- May 18, 2005: asthma attack requiring hospitalization in May – yellowish mucus;

- August 9, 2005 peak flows usually around 500. Came down to 420 to 450;

- September 26, 2005: acute asthma attack requiring hospitalization;

- October 26, 2005: slight improvement in asthma. Peak flows lately around 510, sometimes as high as 600. Mornings are lower – around 420;

- January 25, 2006: Exacerbation of asthma with peak flows dropping to 350 about 1 week ago. Had been up to around 550 before that;

- April 5, 2006: Asthma is as good as going to get and not very good.

Medical Reports Commenting on Causation

The Worker’s Treating Internal Specialist

The internal specialist that saw the worker in the hospital commented on the cause of the worker’s ongoing asthma condition in a March 2006 report:

“[The worker] certainly suffered an acutely severe asthma attack while at work on December 8, 2004. He currently has mild to moderate airflow obstruction, despite the fact that he has been on very aggressive treatment…[He] states emphatically that he does react to his work environment. He has longstanding asthma…I have no real way of knowing if [he] has recovered to his pre-incident status…but certainly even if he has, he is requiring considerably more therapy. He has also quit smoking. It is my contention that [his] condition is worsened by the environmental allergens he is exposed to at work. His asthma is difficult to treat, and even with aggressive therapy, his airflows have not returned to normal. It would certainly not be in [his] interest to be exposed to any allergens that are likely to make his asthma worse. In my opinion, he meets the Workers Compensation Board’s definition of a work related environment provoking an injury which adversely affects a pre-existing condition…”

The worker testified at the hearing that the internal specialist explained to him that the scarring of his lungs was preventing the worker from increasing his lung capacity beyond 59%. He was not however able to say for certain that this was related to the compensable injury.

The Internal Medicine Consultant to the WCB

The internal medicine consultant to the WCB reviewed the worker’s medical file on several occasions. He noted that the worker suffered from quite severe pre-existing asthma. Though there were no spirometry tests prior to December 2004, he noted that the worker’s peak flow rates had normalized at the time of his discharge from hospital on December 21, 2004 and that the spirometry levels had stabilized. He pointed out other conditions that could be impacting on the worker’s condition:

- Smoking: the bronchodilator spirometry tests done in October 2005 did not show reversibility. He commented that one would have to consider the possibility of chronic bronchitis caused by cigarette smoking as an additional cause of airway disease.

- Allergies.

- Infections.

In a June 8, 2006 memorandum he added:

“…Although [the worker’s] asthma is moderately severe, he had remained stable much of the time. I understand he is not being exposed to grain dust at the present time; therefore, one must consider other reasons for continued problems such as exposure to other allergens such as house dust mites, grass pollens, etc. There is also a component of chronic obstructive lung disease due to previous cigarette smoking adding to the airway disease. This component may not respond as well to treatment with steroid…”

Analysis