A brief review of a very hot topic!
In the past few years, climate change took center stage as we watched how our planet was ravaged by uncontrollable wildfires, torrential downpours, and ever-increasing record-breaking heat waves.
It is fair to say that in order to live our lives, raise our families, and take part in activities that give our lives meaning, we are now forced to plan around volatile weather systems.
Who among us have not experienced the frustration of a delayed flight, due to unstable weather? While we all know that we must make changes in how we grow our food and fuel our lives to decelerate climate change, we also need practical short-term solutions to an ever-growing quandary. In other words, what steps can we take to protect our health while we live, work, and play in the summer heat?
For starters, we must know some basic but useful information: We should be able to recognize the difference between heat exhaustion and heat stroke. Both heat exhaustion and heat stroke need to be taken seriously as they, according to the CDC, account for the leading cause of death in athletes. Heat related illnesses also account for many cases of morbidity in the notably young, older athletes, construction workers, military personnel, and firefighters.
Who is at risk?
A big part of successfully identifying and treating heat exhaustion and heat stroke is the ability to recognize who is at risk in the first place. In this regard, lifestyle is a crucial factor when it comes to the degree of vulnerability and simply knowing the professions most at risk of succumbing to heat related illnesses is not enough.
Major risk factors
Important predisposing factors include poor baseline physical fitness, lack of proper baseline hydration, improper clothing, and, even, alcohol intoxication. Other risk factors include acute illnesses such as severe gastroenteritis or a recent upper respiratory tract infection and unfortunately, the chronically ill are not spared either. Many are at increased risk of yielding to heat related illness. Some acquired and congenital conditions to keep in mind are disorders of anhidrosis, sickle cell anemia, heart disease, asthma, chronic obstructive pulmonary disease (COPD), and diabetes mellitus.
Keep in mind that it is not just the conditions that pose the greatest risk, but the prescription and over the counter drugs taken as part of the treatment and management of these conditions that increase the likelihood of heat related illnesses. In particular, diuretics, heart disease and anti-hypertensive prescriptions, antidepressant medications, especially those belonging to the tricyclic antidepressant category all increase the risk of heat related illnesses. Other psychiatric drugs such as Lithium can pose a potential threat as well.
Other factors
Even simple over the counter antihistamines and decongestants can set anyone up for heat related illness. For example, it is not uncommon for a person with an underlying pulmonary condition who has an acute upper respiratory tract infection, to take multiple doses of over-the-counter cold medications in order to get through his/her workday as a construction worker, only to suddenly experience heat exhaustion.
Lastly, those who have alcohol or substance abuse problems can definitely be more prone to quickly becoming ill when exposed to high ambient temperatures.
In short, almost everyone you will come into contact with today can be at increased risk.
How to protect ourselves and others
Now that we have established who is at risk, we must know how we can protect ourselves. If we provide patient care, how do we stratify the severity of illness and render the correct treatment?
Differentiating illnesses
Health care providers can distinguish between heat stroke and heat exhaustion through parameters such as core body temperature, mental status, airway and breathing, circulation, and by taking note of the skin of the affected person. We will discuss key differences that can help quickly differentiate between heat stroke and heat exhaustion.
With heat stroke the skin will appear dry whereas a person suffering from heat exhaustion will continue to sweat.
People affected with heat stroke have very notable mental status changes, such as slurred speech and/or ataxia (loss of normal balance). They may appear obtunded or be hallucinating. They can present with seizures, delirium, and even coma. Thankfully, those experiencing heat exhaustion may only report headache, dizziness, and mild confusion that improves upon treatment.
Other factors include airway and breathing: Those with heat exhaustion may have tachypnea (rapid breathing rate), but there will be no airway compromise.
With heat stroke however, there can be airway compromise due to altered mental status.
Other signs
Other obviously critical signs include pulse, blood pressure, and temperature. People in heat stroke will have core body temperatures of 104 F to 105 F and have tachycardia (fast heart rate) and be hypotensive (have low blood pressure). On the other hand, those with heat exhaustion will have core body temperatures of less than 104 F and will have stable blood pressure despite having tachycardia.
Heat stroke will often present with vomiting and diarrhea, whereas only nausea and vomiting accompany heat exhaustion. Further, those with the latter may complain of headache and weakness due to electrolyte abnormalities but will not present with systemic shock as can happen with heat stroke. Other distinguishing features between heat stroke and heat exhaustion are that the former is complicated by rhabdomyolysis (the destruction of striated muscle cells); acute renal and hepatic failure; and disseminated intravascular coagulation (DIC) which is the condition that inhibits the body’s ability to clot and stop bleeding.
Treatment
Given the many complications associated with these illnesses, prompt treatment is essential. According to the Wilderness Medical Society Guidelines, severity of illness can be mild, which includes cramps and edema. In this case oral fluid and electrolyte replacement along with passive cooling measures suffice. Elevation of extremities are helpful if there is edema. When heat exhaustion is the diagnosis, prompt removal from the offending environment, followed by evaporative cooling or conduction cooling is recommended. Conjointly, hypertonic fluid hydration is essential for fast recovery. Concurrent lab testing should be performed and should include complete blood count (CBC), electrolyte panel, renal and hepatic function panels, CK (creatine kinase), urinalysis, and coagulation studies (PT, PTT, INR). This set of lab data can correctly guide treatment, disposition, and prognosis.
With severe signs and symptoms seen in heat stroke, prompt removal/evacuation from extreme temperatures is warranted while simultaneously supporting air way, breathing, and circulation. Intravenous hydration should begin immediately along with whole body conductive cooling or cold-water immersion. Consider that cold water immersion can slow cooling if severe vasoconstriction and shivering ensue. Again, CBC, electrolyte panel, CK, troponin, renal and hepatic function panels, urinalysis, coagulation studies, drug screen panel, and cardiac monitoring will be required. Treatment of concomitant rhabdomyolysis, acute pancreatitis, acute liver and renal failure, gastrointestinal bleeding, encephalopathy, DIC, and other complications that can arise from systemic inflammatory responses will likely be necessary.
Prevention
As with all illnesses, prevention is paramount. In the case of heat related illness, preparation is the best preventative measure to date.
Here is a brief list of preventative measures to consider:
- Focus on optimizing overall fitness.
- Know historical weather temperatures and plan accordingly.
- Avoid extreme heat and humidity. This is especially helpful for those with acute and chronic illnesses.
- If exercise or outdoor activity cannot be avoided, be sure to hydrate well before exposure and wear clothing with pre-cooling technology (cooling vests). Take frequent brakes and drink water.
- Recognize early symptoms such as excessive thirst, dizziness, fatigue, muscle cramps, and headache.
- When working outdoors consider cooling vests, hats, and other protective gear that can aid the body’s heat loss mechanism. Make use of wearable basal body thermometers that are useful in both hot and cold climates. They may be able to alert the wearer before the onset of symptoms. Many of the aforementioned equipment can be made available to small and large businesses through various OSHA programs.
To recap, heat related illnesses account for days lost from work and school, morbidity, and even death. Recognition of mild to moderate illness and timely treatment can reverse many, if not all of the early signs and symptoms. Prompt evacuation and stabilization of the heat stroke victim can mean the difference between life and death in many cases.
As always, consider the health of our planet when purchasing food, goods, and services.
Stay cool out there!!
Ela Grigorian, MD
Please be sure to listen to our Medcare Business Network podcast featuring Dr. Ela Grigorian and other great guests here!