Understanding the Spectrum of Heat Illnesses

Introduction:

Today, Dr. Rahul Damania, Dr. Pradip Kamat, and their guest,  Dr. Jordan Dent, discuss a critical case involving a 15-year-old male who collapsed during football practice due to exertional heat stroke. The discussion emphasizes the clinical presentation, risk factors, pathophysiology, and evidence-based management of heat stroke and other heat-related illnesses in pediatric patients. The episode also delves into the role of rapid cooling interventions and long-term care to minimize mortality and morbidity.

Case Summary: A 15-year-old male with ADHD collapsed during football practice on a hot, humid day. He presented with:

• Normotension (BP: 101/67 mmHg)
• Tachycardia (HR: 157 bpm)
• Tachypnea (RR: 40 breaths/min)
• Febrile (Rectal temp: 41.8°C/107.2°F)
• Dry, hot skin, GCS of 9
• Lab abnormalities: hyponatremia, hypokalemia, hypoglycemia, elevated creatinine, liver enzymes, lactate, CK, and troponin

After suffering cardiac arrest and undergoing resuscitation, the patient developed multiorgan dysfunction, including seizures, encephalopathy, and cerebral edema. Despite severe initial complications, the patient demonstrated neurological improvement with left-side hemiparesis before discharge.

Key Discussion Points:

1. Etiology and Pathophysiology of Heat Stroke:

• Heat stroke occurs when the body’s thermoregulatory mechanisms fail, leading to dangerous elevations in core body temperature. Exertional heat stroke is common during strenuous physical activity in hot, humid environments.
• Key physiological breakdowns include inadequate sweating, vasodilation dysfunction, and subsequent cellular damage due to hyperthermia.

1. Risk Factors for Exertional Heat Stroke:

• Environmental factors: High temperature, humidity, lack of hydration, and breaks.
• Athlete-related factors: Hypohidrosis, dehydration, medical conditions, and medications (e.g., Adderall).
• Heat illness is the third leading cause of death in high school athletics, with American football players particularly at risk.

1. Spectrum of Heat-Related Illness:

• Heat Cramps: Involuntary muscle contractions due to dehydration and electrolyte imbalance.
• Heat Syncope: Transient loss of consciousness due to heat exposure.
• Heat Exhaustion: Milder heat illness with core temperature < 104°F, potentially progressing to heat stroke if untreated.
• Heat Stroke: Life-threatening with core temperature ≥ 104°F, CNS dysfunction, and risk of multiorgan failure.

1. Management of Heat Stroke:

• Rapid Cooling: Immediate cooling to bring core temperature down to 39°C within 30 minutes is critical. Methods include ice packs, cold water immersion, and core cooling techniques (cold IV fluids, gastric lavage).
• Supportive Care: Management of shock, electrolyte imbalances, rhabdomyolysis, DIC, and ARDS.
• Monitoring and Long-Term Care: Continuous EEG, fluid management, and rehabilitation are key in managing neurological and systemic complications.

1. Differentiating Heat Stroke from Fever:

• Fever results from a reset of the hypothalamic setpoint due to pyrogens, while heat stroke involves the failure of thermoregulation without a change in the hypothalamic setpoint.

1. Case Outcome:

• The patient initially suffered significant neurological damage but improved with intensive care and rehabilitation. By discharge, the patient showed notable recovery, though with some lasting deficits.

Key Takeaways:

1. Heat stroke is a medical emergency with a high risk of mortality and long-term complications if not treated promptly.
2. Early recognition, rapid cooling, and a multidisciplinary approach are critical to improving outcomes.
3. Athletes and children engaging in strenuous activities in hot environments should be closely monitored for signs of heat-related illness.

References:

1. Fuhrman, B., & Zimmerman, J. J. (2020). Hyperthermic Injury. In Textbook of Pediatric Critical Care (pp. 1327-1331).
2. Rogers, M. C., et al. (2016). Thermoregulation. In Rogers' Textbook of Pediatric Intensive Care (pp. 546-552).
3. Ishimine, P. (2022). Heat Stroke in Children. UpToDate. Retrieved from www.uptodate.com/contents/heat-stroke-in-children.
4. Jardine, D. S. (2007). Heat Illness and Heat Stroke. Pediatrics in Review, 28(7), 249–258. https://doi.org/10.1542/pir.28-7-249.
5. Patel, J., et al. (2023). Critical illness aspects of heatstroke: A hot topic. Journal of Intensive Care Society, 24(2), 206-214. https://doi.org/10.1177/17511437221148922.
6. Ramirez, O., Malyshev, Y., & Sahni, S. (2018). It’s Getting Hot in Here: A Rare Case of Heat Stroke in a Young Male. Cureus, 10(12), e3724. https://doi.org/10.7759/cureus.3724.