Clinical Recognition and Management of Canine Heat-Related Illness: From Early Signs to Emergency Care

Timely recognition and appropriate management of heat-related illness are critical determinants of clinical outcomes in dogs. The progression from mild symptoms to life-threatening systemic failure can be rapid, making early intervention essential. 

Recent research has introduced structured approaches to grading severity and has challenged traditional treatment myths, offering veterinarians clearer guidance for both diagnosis and management ¹. 

Clinical Progression: Recognising the Spectrum 

Heat-related illness is not a binary condition but a continuum ranging from mild to severe disease. 

• Mild cases present with persistent panting, lethargy, and reluctance to move  

• Moderate cases include gastrointestinal signs, hypersalivation, and episodic collapse  

• Severe cases involve neurological dysfunction, seizures, organ failure, and coagulopathies  

Importantly, dogs presenting with severe HRI have a 65-fold increased risk of death compared to mild cases^1,2. This underscores the importance of early detection and intervention. 

Clinical Grading Tool for Heat-Related Illness 

Below is a structured adaptation of the VetCompass clinical grading tool^1,3: 

This grading system provides a practical framework for triage and treatment planning in clinical settings. 

Limitations of Body Temperature 

A critical clinical insight is that body temperature alone is not a reliable indicator of disease severity. Dogs may present with normal or even low temperatures if cooling has already been initiated³. 

Conversely, healthy exercising dogs can reach temperatures above 42°C without developing HRI¹. 

Therefore, veterinarians must interpret temperature in conjunction with clinical signs and patient history. 

Debunking Cooling Myths 

Traditional recommendations often advocate gradual cooling using tepid water, based on concerns about vasoconstriction and shock. However, recent evidence has firmly challenged this approach. 

Studies in human and equine medicine demonstrate that rapid cooling using cold water immersion or evaporative methods is more effective¹. 

In dogs: 

• Tap water (15–16°C) is effective for conscious patients  

• Colder water (1–11°C) may be more effective for comatose dogs  

Evaporative cooling, combining water application with airflow, is particularly useful in geriatric or compromised patients. 

“Cool First, Transport Second”: A Practice-Changing Principle 

One of the most important clinical takeaways is the recommendation to initiate active cooling before transport¹. 

Delaying cooling until arrival at a veterinary clinic can significantly worsen outcomes. Rapid reduction of body temperature is crucial, as the duration of hyperthermia directly influences disease severity¹. 

Monitoring During Treatment 

While rapid cooling is essential, clinicians must also monitor for hypothermia, particularly during aggressive cooling. Evidence on its impact on mortality is mixed, but careful monitoring remains best practice¹. 

Supportive care should include: 

• Fluid therapy  

• Electrolyte management  

• Glucose monitoring  

• Organ-specific support  

Conclusion 

The management of canine heat-related illness has undergone a notable shift, with current approaches prioritizing rapid intervention, structured clinical assessment, and evidence-based cooling techniques. 

For veterinarians, success depends on early recognition, prompt triage, and decisive action. Integrating these updated treatment strategies, along with effective client education, can significantly improve clinical outcomes and reduce mortality associated with canine heat-related illness.  

Reference 
1. Bradbury J, Hall E, Carter A, O'Neill DG. Canine heat-related illness–new perspectives from recent research. Companion Animal. 2023 Jul 2;28(7):2-5. https://www.magonlinelibrary.com/doi/pdf/10.12968/coan.2023.0015 

2. Hall EJ, Carter AJ, Chico G, Bradbury J, Gentle LK, Barfield D, O’Neill DG. Risk factors for severe and fatal heat-related illness in UK dogs—a VetCompass study. Veterinary Sciences. 2022 May 11;9(5):231. https://www.mdpi.com/2306-7381/9/5/231 

3. Hall EJ, Carter AJ, Bradbury J, Barfield D, O’Neill DG. Proposing the VetCompass clinical grading tool for heat-related illness in dogs. Scientific Reports. 2021 Mar 25;11(1):6828. https://www.nature.com/articles/s41598-021-86235-w.pdf