Clinical Recognition and Evidence-Based Management of Canine Heat-Related Illness

Canine HRI presents across a continuum from mild to severe disease. Early clinical signs include persistent panting, tachypnoea, lethargy, and reduced willingness to move. Moderate disease may involve gastrointestinal disturbances, hypersalivation, collapse, or isolated seizure activity. Severe HRI is characterised by neurological dysfunction, coagulopathy, gastrointestinal haemorrhage, and multi-organ involvement¹. 

Disease severity is strongly associated with outcome. Dogs presenting with severe HRI have significantly increased mortality risk compared to those with mild presentations². 

Limitations of Body Temperature 

Body temperature should not be used in isolation to diagnose or grade HRI. Dogs may exhibit elevated temperatures during exercise without pathological consequences, while others may present normothermic or hypothermic following initial cooling despite ongoing systemic injury^{1, 3}. 

Clinical decision-making should therefore integrate patient history, exposure risk, and presenting clinical signs. 

Evidence-Based Cooling Strategies 

Rapid reduction of core body temperature remains the cornerstone of HRI management. Contemporary evidence supports active cooling methods, including cold-water immersion and evaporative cooling, as the most effective interventions^4,5 

Water temperatures of approximately 15–16°C have demonstrated effective cooling in conscious dogs, while colder temperatures may be appropriate in more severe or comatose cases¹. Evaporative cooling—application of water combined with airflow—is recommended in patients where immersion is not feasible or may pose risk¹. 

The use of wet towels alone is considered less effective and should not replace active cooling methods¹. 

Pre-Hospital and Clinical Management 

Current best practice advocates initiating cooling prior to transportation to a veterinary facility (“cool first, transport second”) to minimise duration of hyperthermia, a key determinant of tissue damage¹. 

During cooling, careful monitoring is required to avoid iatrogenic hypothermia, although its direct impact on prognosis remains unclear¹. 

Supportive Care and Monitoring 

Definitive management includes intravenous fluid therapy, monitoring of electrolytes and glucose, and assessment of organ function, particularly hepatic and renal parameters. Additional supportive interventions may be required depending on clinical presentation, including respiratory, neurological, and coagulation support¹. 

Conclusion 

Timely recognition, rapid evidence-based cooling, and comprehensive supportive care are critical to improving outcomes in canine HRI. Veterinary professionals play a central role in both acute management and preventive client education, particularly for high-risk populations. 

References  

1. Hall EJ, Carter AJ, Bradbury J, Barfield D, O’Neill DG. Proposing the VetCompass clinical grading tool for heatrelated illness in dogs. Sci Rep. 2021;11(1):6828. https://doi.org/10.1038/s41598-021-86235-w   

2. Hall EJ, Carter AJ, Chico G, et al. Risk Factors for Severe and Fatal Heat-Related Illness in UK Dogs-A VetCompass Study. Vet Sci. 2022;9(5):231. https://doi.org/10.3390/vetsci9050231  

3. Carter AJ, Hall EJ. Investigating factors affecting the body temperature of dogs competing in cross country (canicross) races in the UK. J Therm Biol. 2018;72:33– 38. https://doi.org/10.1016/j.jtherbio.2017.12.006  

4. Gaudio FG, Grissom CK. Cooling Methods in Heat Stroke. J Emerg Med. 2016;50(4):607–616. https://doi.org/10.1016/j.jemermed.2015.09.014  

5. Kanda J, Nakahara S, Nakamura S et al. Association between active cooling and lower mortality among patients with heat stroke and heat exhaustion. PLoS One. 2021;16(11):e0259441. https://doi.org/10.1371/journal.pone.0259441