PHARMACY CONNECTION ARTICLE

Coroner’s Inquest into Death Due to Hyperthermia

Published on: August 1, 2014

On the day of the incident, B.F. was working as usual on the installation of a residential lawn sprinkler system. It was a hot summer day with a maximum temperature in the local area, as measured at Pearson Airport, of 29.2 degrees Celsius. Water and liquids were available and he was seen drinking over the course of the workday. He had voiced no concerns and did not appear to be in any distress, according to his coworkers. However at the end of the day, during clean up, B.F., who was normally a quiet and reserved communicator, stated that he was feeling hot. His coworkers advised him to sit down in an air-conditioned van. Approximately 15 minutes later he exited the van and walked towards another van at the site. He proceeded to collapse and was attended by his coworkers. A passing runner with first aid experience began cardiopulmonary resuscitation. Emergency Medical Services personal found him to have absent vital signs and an initial temperature of 39.9 degrees Celsius.

Resuscitation attempts were initiated and continued en route and in the Emergency Room without success. An autopsy confirmed that B.F. died as a result of environmental hyperthermia and that he had evidence of significantly advanced premature coronary artery disease.

The Coroner’s jury made a recommendation to the Ontario College of Pharmacists, Ontario College of Family Physicians, College of Physicians and Surgeons of Ontario, and to the Ontario Medical Association as follows:

Recommendation:

Increase awareness among Health Care Providers of heat stress and how some medications may impact upon a person’s ability to deal with heat stress.

Coroner’s Comments:

Testimony was provided that there are resources presently available to frontline healthcare providers that can effectively facilitate their knowledge of heat stress as it relates to their patients and the medications they prescribe or dispense, and that the providers are unaware of the existence of these resources.

Preventing Heat-Related Illness

Chia Hui Chung, BSc., PharmD Candidate (2016),
University of Toronto Leslie Dan Faculty of Pharmacy

In the summer months, pharmacists are often relied upon to educate patients on matters such as sun protection and sun sensitivity in relation to drug therapy. However, this case teaches us that the effect of drugs on temperature regulation cannot be overlooked. Hyperthermia refers to an increase in core body temperature beyond 38.2 degrees Celsius, thereby producing symptoms that result from the interference of our own heat dissipating mechanisms. Resting, cooling and rehydrating with oral rehydration solution provide the mainstay of treatment for hyperthermia.¹

Risk Factors

Pharmacists need to identify the key risk factors in order to respond to red flag situations that pertain to heat-related illness (as seen in Table 1). Those that are most susceptible to developing hyperthermia include: infants and young children, the elderly, outdoor labourers and the physically active.²

Table 1: Risk Factors for Heat-Related Illness²

Health Factors

Behavioural/Environmental Factors

Cardiovascular disorders (hypertension, coronary artery disease, peripheral artery disease, heart conduction disorders) Pulmonary disorders (chronic obstructive pulmonary disease, asthma) Renal disorders (renal failure) Psychiatric disorders (dementia, depression, schizophrenia, Alzheimer’s) Skin conditions (scleroderma and miliaria) Hyperthyroidism Metabolic conditions (diabetes, obesity) Alcoholism

Wearing heavy clothing or equipment Poor physical condition; confined to bed Hot, humid environment without air conditioning or proper ventilation Exercising without breaks

Heat Exhaustion Versus Heat Stroke

Heat exhaustion occurs during the first signs of increased core body temperature due to excessive salt and water loss. It can be accompanied with symptoms such as anxiety, headache, nausea and vomiting. The skin becomes red, moist and hot to the touch. The heart rate may increase while blood pressure may drop. Strenuous activity should be avoided for several days.¹

Heat strokes are the most dangerous and life-threatening forms of hyperthermia, which can occur when heat exhaustion is left untreated. There are two types of heat stroke: classic and exertional. Classic heat strokes primarily affect the elderly with chronic illness, and the skin becomes hot and dry. Exertional heat strokes occur in younger, healthy individuals due to strenuous physical activity and the skin becomes moist due to profuse sweating. Both types of heat stroke will likely cause changes in mental state (e.g., delirium, coma). Patients should be cooled and be taken to the emergency room immediately.²

Table 2: Medications Shown to Decrease Regulation of Body Temperature³

Mechanism	Drug Class	Examples
Reduction of perspiration	Anticholinergics	scopolamine
Reduction of perspiration	Antihistamines	brompheniramine
Reduction of perspiration	Antiparkinsonian agents	levodopa, benztropine
Reduction of perspiration	Antipsychotics	olanzapine
Reduction of perspiration	Beta-blockers	atenolol, metoprolol
Reduction of perspiration	Calcium channel blockers	amlodipine
Reduction of perspiration	Diuretics	furosemide
Vasoconstriction of cutaneous vessels	Sympathomimetics	pseudoephedrine
Disruption of centrally-induced thermoregulation	Antidepressants	SSRIs (fluoxetine), TCAs (amitriptyline)
Disruption of centrally-induced thermoregulation	Amphetamines	Adderall (amphetamine and dextramphetamine)
Increased heat production	Excessive thyroid medication	levothyroxine

Medications that Increase Risk for Heat-Related Illness

Certain medications can predispose patients to hyperthermia through various mechanisms (examples are illustrated in Table 2). Pharmacists should be able to identify these provoking agents based on a patient’s medical history, clinical presentation and timing of symptom onset to mitigate the risk of irreversible sequelae. In light of the Coroner’s findings, pharmacists are reminded of the Professional Responsibility Principles, which call on members to assess the appropriateness of therapy by recognizing situations that may cause the patient harm. To facilitate information sharing and professional collaboration within health care teams, proper documentation of patient counseling regarding heat-related illnesses is also advised. Clinical encounters concerning medications that affect body temperature regulation should include the following recommendations:

• Know the signs/symptoms of heat-related illnesses
• Drink at least two cups of cool water every hour during moderate physical activity⁴
• Limit coffee, tea, cola and alcoholic beverages.²
• Avoid heavy outdoor activities between 10 a.m. and 3 p.m.²
• Schedule frequent rest periods from outdoor activities.²
• Wear loose-fitting, light-coloured clothing.⁴

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References

1. Canadian Pharmacists Association. “Thermoregulatory Disorders in Adults.” Therapeutic Choices Sixth Edition (2011). Print
2. Canadian Pharmacists Association. “Heat-Related Disorders.” Therapeutic Choices for Minor Ailments: The Best Available Evidence for Nonprescription Therapy (2013). Print
3. Health Canada. Acute Care During Extreme Heat: Recommendations and Information for Health Care Workers (2013). Available from: http://www.hc-sc.gc.ca/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/climat/actue_care-soins_actifs/actue_care-soins_sante-eng.pdf
4. United States Department of Labour (Occupational Safety and Health Administration). Protecting Workers from the Effects of Heat Fact Sheet. Available from: https://www.osha.gov/OshDoc/