WORKPLACE SAFETY AND INSURANCE BOARD
APPEALS RESOLUTION OFFICER DECISION
DECISION NUMBER: 20150011
DECISION DATE: March 19, 2015
OBJECTING PARTY: Worker
REPRESENTED by: Worker Representative
RESPONDENT: Employer (Not Participating)
HEARING: February 24, 2015, Toronto
HEARD by: L. Mansueti, Appeals Resolution Officer
ISSUE
The worker objects to the decision dated November 29, 2011 denying entitlement to further benefits from June 12, 2011.
The worker seeks:
Entitlement to benefits for post-anoxic cortical myoclonus, including the recognition of a permanent impairment.
The reinstatement of loss of earnings (LOE) benefits from June 12, 2011 onward.
BACKGROUND
On or about May 13, 2011 the worker was driving a transport truck that had a leak in the exhaust manifold. The worker developed headaches and nausea, which he attributed to fume inhalation from the leak. He was 46 years of age at the time of injury, working as a Transport Driver. He had worked with the employer for approximately 5 months.
Entitlement was accepted for fume inhalation. Loss of earnings (LOE) benefits were approved from May 15, 2011 until June 2, 2011 inclusive. The worker returned to regular duties on June 3, 2011.
The worker stopped working on June 12, 2011, citing he was experiencing persistent headaches.
The operating area denied entitlement to further benefits as per the decision dated November 29, 2011. The worker objected to the November 29, 2011 decision. The reconsideration letter dated June 10, 2013 confirmed entitlement was not in order.
The worker objected to the denial of his recurrence and that is now the issue before the Appeals Services Division.
AUTHORITY
Section 2, 15, 33, 43 and 46 of the Workplace Safety and Insurance Act (WSIA), 1997
Operational Polices:
15-05-01 Resulting from Work-Related Disability/Impairment
18-03-02 Payment and Reviewing LOE Benefits (Prior to Final Review)
18-05-03 Determining the Degree of Permanent Impairment
Adjudicative Advice Document: Practice Guidelines For Ordering LOE Benefit Arrears Under WSIA
ANALYSIS
I have reviewed and considered the information in the record as well as the worker’s testimony in accordance with the above noted legislation, policies, and advice document.
The worker indicated on the Worker’s Report of Injury (Form 6) he experienced diesel exhaust inhalation in 2005 while working with another employer, and remained off work for 2 to 3 weeks. There is no indication a Workplace Safety and Insurance Board (WSIB) claim was filed for this incident. The worker testified he returned to work without incident. He stated he did not experience any lasting effects from the 2005 exposure.
The worker also indicated on the Form 6 he experienced diesel exhaust inhalation on March 23, 2011. The worker testified to his estimation the truck he had been driving had a leak, thus he reported it to the employer. The worker indicated he experienced some symptoms of dizziness, nausea, and headache. He missed one day of work due to his symptoms, and informed the employer of the leak. There is no indication in the record of an investigation.
Workplace Accident
On or about May 13, 2011 the worker was driving transport truck 303, and was exposed to diesel exhaust due to a manifold leak. The worker testified he was travelling from Cambridge, Ontario to Windsor, Ontario. He suspected there was an exhaust leak in the truck and contacted the distribution centre. He was informed to return the truck to the yard. The worker stated he had a bad headache, and drove back with the window open and stopped a few times for fresh air. The worker indicated he spent a minimum of 8 hours in the truck. As per the Form 6, the truck he was assigned on May 14, 2011 also had an exhaust leak. It is noted the employer confirmed there was in fact a broken manifold stud on the cylinder causing a slight leak in truck 303, the one the worker had driven on May 13, 2011. As such, there is one confirmed occurrence of diesel fume exposure.
On May 15, 2011 the worker did not report to work. He indicated he could hardly get up from bed due to his symptoms of dizziness, headache, and nausea. He sought medical attention on May 19, 2011 as his symptoms persisted. The worker returned to regular duties on June 3, 2011. The worker reported as per the Form 6 he was not fully recovered when he returned to work. He advised he continued to experience minor headaches and “difficulty thinking.”
The worker stopped working on June 12, 2011. The worker testified he continued to experience persistent headaches, dizziness and nausea, which he attributed to the fume inhalation. The worker was noted to have taken a leave of absence from work. The employer’s investigation indicated there was no evidence of a new exposure to fumes.
Medical Evidence
He sought medical attention on July 7, 2011. The urgent care clinic report indicated the worker presented with headaches and nausea. The physician indicated the worker was capable of returning to work on August 18, 2011 with a restriction of no exposure to exhaust fumes. The worker was also referred to a neurologist. The worker remained off work.
The neurologist assessed the worker on October 28, 2011. The report indicated the worker experienced two exposures to carbon monoxide while working on diesel trucks, one occurrence in February 2011 and the other in May 2011. The worker reported he felt unwell at work in June 2011, left work, and lost all memory of how he arrived home. The worker presented with chronic headaches, with some improvement. He also reported muscle twitching, which increased in distribution, frequency, and intensity. The neurologist observed the worker had occasional myoclonic appearing movements (rapid muscle jerks), involving his head, trunk, upper or lower extremities; however, when the worker was engaged in an activity, the movements disappeared. He surmised the carbon monoxide exposure could result in myoclonus. An electroencephalography (EEG) was completed and yielded normal findings. A magnetic resonance imaging (MRI) scan of the head and cervical spine was arranged.
A WSIB Medical Consultant (MC) provided a medical opinion on November 25, 2011. The MC indicated the worker’s lost time from June 12, 2011 was considered to be outside the scope of his claim.
An MRI of the worker’s head dated January 8, 2012 yielded normal results.
The neurologist reassessed the worker on February 7, 2012. The worker continued to report myoclonic movements, and reported an episode of losing consciousness for about an hour. The worker was referred to a specialist with expertise in myoclonic disorders.
The worker’s general practitioner (GP) as of June 2012, submitted chart notes to the record. The GP noted on June 26, 2012 the worker had myoclonic jerks only when he was being observed or when asked about them. These movements stopped when he was busy with something. The worker reported he had slight control over the movements. The GP observed the same myoclonic jerks on July 11, 2012 only when the worker was not concentrating on other tasks. He advised the worker on November 9, 2012 she did not think the worker had myoclonus, and also indicated the worker’s problems were not due to exhaust exposure.
The worker was assessed by a physician at the Morton & Gloria Shulman Movement Disorders Centre on January 14, 2013. The worker’s chief complaint was generalized myoclonus. His symptoms included headaches, dizziness, confusion, disorientation, nausea, speech difficulties, and difficulties with walking and thinking. The worker recounted he developed involuntary movements in June or July 2011, involving his right thumb, lower limbs, left upper limb, trunk, and neck. He advised the movements became more severe and frequent 3 to 6 months later. The worker reported the movements were slowly reducing in severity and frequency, citing drinking beer helped reduce them. The physician noted the worker’s attention, language, and memory were abnormal. The worker’s involuntary movements were noted to be “post-anoxic, probable.” Finger tapping was thought to increase the frequency of the movements while alcohol and mental activities reduced their frequency. These movements were thought to be compatible with myoclonus, particularly cortical myoclonus. The worker was recommended to undergo an electrophysiological assessment and undergo another brain MRI scan.
The subsequent MRI brain scan dated January 20, 2013 was unremarkable.
A second WSIB MC provided a medical opinion on May 28, 2013 with respect to the worker’s occupational fume inhalation and myoclonic movements. The MC surmised it was not improbable the carbon monoxide exposure was at least in part, if not entirely, responsible for the delayed onset myoclonus.
A Movement Disorders Neurologist, assessed the worker on October 23, 2013. A polygraphic muscle electromyography (EMG) and an EEG were performed. Myoclonic discharges were observed in the truncal muscles bilaterally as well as in the right arm and leg. The short duration of the EMG discharges and the pattern of the spread suggested a cortical or brainstem origin.
On November 19, 2013 the Ministry of Transportation downgraded the worker’s license from a Class ‘A’ to a Class ‘G’ and also suspended his driver’s licence. The worker testified his driver’s licence remains suspended.
The neurologist who originally examined the worker indicated in his December 16, 2013 report the worker was exposed to carbon monoxide which caused a lack of oxygen to the brain, resulting in the development of post-anoxic myoclonus, a movement disorder following deprivation of oxygen to the brain. He explained:
Oxygen carrying hemoglobin is tightly bound to carbon monoxide with exposure thus impairing the ability of the hemoglobin molecules to deliver oxygen to tissues. Thus following carbon monoxide exposure, hemoglobin is bound to this and cannot carry oxygen, the blood circulating [to the] brain therefore does not deliver sufficient oxygen and the brain thus becomes dysfunctional.
The Movement Disorders Neurologist submitted a letter to the operating area dated
January 16, 2014. He indicated he assessed the worker on three occasions; the most recent visit was on January 13, 2014. The worker’s electrophysiological studies indicated the myoclonus arose from the cortex or brainstem. He indicated the worker had severe spontaneous and action induced myoclonus stemming from anoxia.
On August 18, 2014 the worker returned to the Movement Disorders Neurologist. He referenced electrophysiological studies from 2013 which showed findings consistent with brainstem or cortical myoclonus. The worker continued to report severe involuntary truncal movements which increased with physical activities and stress. The neurologist reiterated the cause of the worker’s myoclonus was likely post-anoxic following carbon exhaust fume exposure noting there was no indication of a neurodegenerative disease or any anoxic event to which his condition could be attributed.
The neurologist who originally examined the worker indicated in the report dated
September 17, 2014 the worker “quite clearly had carbon monoxide exposure in the workplace as indicated by myself and Dr. Chen.”
Assessment
Operational Policy 15-05-01 states, in part:
Injury resulting from work-related injury
Entitlement for any secondary condition is accepted when it is established that a causal link exists between it and the work-related injury.
Entitlement was accepted for diesel fume inhalation only. Following the worker’s carbon monoxide exposure on May 13, 2011 his symptoms continued to persist and worsen over time. It was further noted the worker went on to develop myoclonic movements. A neurologist initially assessed the worker in October 2011, and suggested the worker’s carbon monoxide exposure may have caused myoclonus; however, it was not confirmed. The medical evidence submitted in 2011 and 2012 was insufficient in supporting a relationship between the worker’s diesel fume inhalation and his subsequent myoclonus. In fact, the WSIB MC opined the worker’s condition was outside the scope of his claim and the GP was of the opinion the worker did not have a movement disorder. It must be noted there was limited medical information regarding the worker’s condition at that time. As such, I have not placed significant weight on these medical opinions.
It was not until the worker was assessed at the Movement Disorders Centre on
January 14, 2013 that the worker’s myoclonus was thought to be post-anoxic. A second WSIB MC, contended “it is not improbable the exposure was at least in part, if not entirely, responsible for the delayed onset myoclonus.” The MC prefaced this by stating it was open for debate on the absence of an exposure sufficiently significant to require hospital admission, and lack of evidence of other organ involvement.
Two neurologists continued to follow the worker’s condition, and determined he did in fact have post-anoxic myoclonus, a movement disorder following the deprivation of oxygen to the brain. The worker’s 2013 electrophysiological studies indicated the myoclonus derived from the cortex or brainstem. The first neurologist surmised in his December 16, 2013 report, “It seems pretty clear that his movement disorder which is myoclonic in nature has been the result of damage to the brain (specifically to cortical functioning) which derived from impaired oxygen deliver due to carbon monoxide exposure.” The second neurologist explained in the January 16, 2014 report, the onset of post-anoxic myoclonus is typically delayed from the time of injury, which may range from days to months. He stated:
(The worker’s) post-anoxic myoclonus is likely related to exhaust fume exposure as he has no other cause for post-anoxic myoclonus such as cardiac arrest or severe asthma attack. In my opinion, “delay in seeking medical attention” and absence of hospital admission are not valid reasons for denying (the worker’s) claim as the onset of post-anoxic myoclonus is usually delayed from the time of injury. I do not see any other cause for (the worker’s) post-anoxic myoclonus other than the exhaust fume exposure.
I have placed significant weight on the assessments and opinions provided by The neurologists. They indicated the worker’s myoclonus was a result of oxygen deprivation most likely caused by the exposure to carbon monoxide. I accept it is more probable than not the worker’s post-anoxic cortical myoclonus developed as a result of his occupational diesel fume inhalation on May 13, 2011. The preponderance of medical evidence submitted to the record supports the worker developed this secondary condition following the diesel inhalation at work. There does not appear to be any other reasonable explanation for his condition, as there is no evidence the worker suffered a cardiac arrest or experienced a severe asthma attack. Furthermore, the fact the post-anoxic myoclonus typically has a delayed onset is in keeping with the worker’s late development of symptoms.
The medical evidence submitted to the record supports there is a strong causal link between the worker’s diesel fume inhalation on May 13, 2011 and his subsequent post-anoxic cortical myoclonus. As such, entitlement to benefits is in order for post-anoxic cortical myoclonus. The evidence in the record also supports this is a permanent condition. As such, I find the worker is entitled to a NEL assessment for post-anoxic cortical myoclonus.
The worker is entitled to the reinstatement of LOE benefits from June 12, 2011. The worker testified he has been off work since June 12, 2011 and in receipt of Canada Pension Plan (CPP) disability benefits as well as Ontario Disability Support Program (ODSP) benefits.
I accept the worker was and continues to be unable to resume his pre-injury job as a Transport Driver due to his compensable condition, particularly because of the severity of his symptoms and the fact his driver’s licence remains suspended. I make no determination as to whether the worker is totally disabled and unable to work, as this decision ought to be made by the operating area following a Work Transition (WT) assessment.
CONCLUSION
I conclude:
Entitlement is in order for post-anoxic cortical myoclonus, including the recognition of a permanent impairment. The worker is entitled to a non-economic loss (NEL) assessment for said condition.
Loss of earnings (LOE) benefits are in order from June 12, 2011 less benefits received from other sources.
The worker is entitled to a Work Transition (WT) assessment. LOE benefits are in order while the worker participates and cooperates with the WT process.
The level and duration of benefits flowing from this decision once WT contact has been made shall be determined by the operating area.
The worker’s objection is allowed.
DATED March 19, 2015
L. Mansueti
Appeals Resolution Officer
Appeals Services Division