Why Is My Dog Or Cat's Blood Electrolyte Balance Abnormal ?













Ron Hines DVM PhD

To see what normal blood and urine values are, go here

For an explanation of causes of most abnormal blood and urine tests, go here

To see how tests are grouped, go here

The Electrolytes In You Pet's Blood

Many of the causes for electrolyte disturbances are the same as the causes of an abnormal anion gap. Read about those here.

Electrolytes are the positively or negatively charged ions that circulate free in you pet’s blood and other body fluids. They are the charged halves (cations or anions) of the various  salts that are dissolved in your pet's blood stream.

The important electrolytes are sodium (Na+), potassium (K+), calcium (Ca2+) magnesium (Mg2+), chloride (Cl−), phosphate (HPO42−) and CO2 (90% circulating as bicarbonate aka HCO3−).

Follow their name links to understand what problems make each one go up or down and the symptoms an imbalance of each is likely to produce in your pet.

The proper balance of electrolytes in your dog or cat ’s blood is regulated by its kidneys under the control of antidiuretic hormone (vasopressin, ADH, AVP) released from its pituitary gland, aldosterone produced by its adrenal glands, and parathyroid hormone (PTH) produced by the parathyroid glands in its neck.


The signs of electrolyte disturbances in dogs and cats include:

Changes in your pet’s breathing patterns

Changes in heart rate.

Muscle weakness



Without treatment, symptoms tend to steadily become worse and often result in medical emergencies.

Along with providing supplemental oxygen, one of the first things veterinarians at emergency centers check and correct are electrolyte imbalances. They do that by providing customized intravenous fluids designed to raise or lower specific blood electrolyte ions. 

Some common causes of electrolyte imbalance in dogs and cats that come to mind are:

Sustained periods of vomiting

Diarrhea (as occurs in Addison’s disease, bacterial and viral enteritis and uremia)


Chronic kidney disease

High fluid loss through the urine, such as seen in diabetes

Chronic intestinal disease, such as IBD or triaditis that limit electrolyte absorption from food

Acute pancreatitis (dog, cat)

FUS Feline Urological Syndrome obstructions in cats

Failure to eat, a diet unbalanced in minerals. Gastrointestinal foreign bodies and overuse of phosphate binding agents can also cause electrolyte disturbances.