Dehydration in Dogs

Dehydration describes insufficient water available to maintain blood pressure and support bodily functions. Water is lost during normal bodily functions like panting, sweating (from the foot pads only in dogs), and urination. These paths of water elimination also result in electrolyte loss. Electrolytes are dissolved minerals (salts) critical to muscle function, including heart muscle. If water is not replaced through drinking at the same rate it is eliminated, widespread muscle and organ dysfunction can result.

Healthy dogs regulate thirst and hydration automatically, which prevents dehydration. Dogs normally do not become dehydrated unless they do not have access to water and there is no need to do things in an effort to get them to drink more.

Dehydration is a serious condition which is a common, secondary feature of many diseases. Mild dehydration often responds to management at home whereas severe dehydration requires urgent veterinary attention.

Young, old, or unwell dogs have an increased risk of dehydration as they are less able to tolerate fluid loss.

Symptoms vary significantly depending on the percentage of fluid lost from the total blood volume. Mild symptoms appear at 5% dehydration, severe symptoms develop at 10% dehydration. Ultimately, dehydration results in loss of effective blood volume, shock, and death.

Dehydration results from inadequate intake or excessive loss of fluids and electrolytes.

Many conditions may cause excessive loss of fluid.

In addition, severe episodes of vomiting and/or diarrhea can result in dehydration.

Dogs with dehydration present with progressive symptoms if not addressed promptly.

Diagnosis of dehydration involves:

• Physical examination
• Blood work
• Urinalysis
• Testing for hormonal conditions
• Ultrasound

Treatment involves correction of dehydration alongside management of the underlying condition. Symptomatic treatment of dehydration includes:

• Oral electrolyte solution
• Fluid therapy
• Correction of electrolyte imbalance

Once dehydration is resolved, medical or surgical management of the underlying disease process is necessary to prevent recurrence.

Prognosis depends on the severity of dehydration, response to treatment, and the primary disease process.

Young dogs with acute diarrhea sometimes develop mild dehydration which is often self-limiting or responds to management at home.

Severe dehydration and electrolyte imbalances are seen in serious conditions, such as Addison's disease and heat stroke, which may be fatal without rapid diagnosis and treatment.

Prevention involves early identification of dogs where intake is not adequately aligned with fluid losses.

Common presentations are preventable by:

• Not keeping dogs in hot cars
• Seeking veterinary attention for cases of vomiting or diarrhea that do not resolve after a few days
• Prompt diagnosis of increased thirst or increased urination
• Ensuring easy access to food and water for old and unwell animals

Dehydration in dogs is a common secondary feature of any condition that results in fluid or electrolyte imbalance.

• Oral electrolyte solution
• Fluid therapy
• Correction of electrolyte imbalance
• Medical or surgical management of underlying disease process