Excess Sodium in the Blood in Dogs

By PetMD Editorial on Mar. 28, 2010

Hypernatremia in Dogs

Electrolytes are very important for many functions in the body. They are required for normal heart and brain functions, fluid balance, to deliver oxygen, and many more. A very delicate balance is required, for each electrolyte has a specific level in the body. Sodium is required for many vital functions in the body including: the regulation of blood pressure, blood volume, the transmission of nerve impulses (signals), as well as the maintenance of acid/base balance in the body.

The term hypernatremia means higher than normal concentrations of sodium in blood. Such elevations are commonly seen in abundant loss of water through gastrointestinal tract along with sodium or low water intake. A common source is sodium chloride (NaCl, table salt). Alterations in sodium levels usually accompany chloride level changes, and symptoms related to both are present together.

Symptoms and Types

  • Increased thirst (polydipsia) and consumption of water
  • Confusion and disorientation
  • Coma
  • Seizures
  • Other symptoms may be related to underlying cause
  • Vomiting
  • Diarrhea
  • High water loss through urine (as seen with diabetes)
  • Intravenous fluid therapy containing NaCl
  • Lower water intake
  • High oral sodium intake (rare)


Your veterinarian will take a detailed history of your dog, including a history of any previous medical treatment. He or she will then perform a complete physical examination. Routine laboratory tests include: complete blood count, biochemistry profile, and urinalysis, which will reveal high levels of sodium along with other abnormalities. For dogs with diabetes, urinalysis will reveal changes in urine, including low sodium levels. More specific testing for diagnosis of underlying diseases may need to be carried out.


Fluid therapy is commonly used to correct the electrolyte balance. In dehydrated dogs, fluid therapy needs to be carried out over some time to correct fluid and electrolyte derangements. Your veterinarian will measure the sodium and other electrolyte levels during and after the treatment to ensure that levels of electrolytes are within normal ranges. Treatment of underlying causes (e.g., diabetes) is essential for complete resolution of the problem and to prevent future episodes.

Living and Management

Follow guidelines given by your dog’s veterinarian. Ensure continuous supply of water for those patients with diabetes. A sodium restricted diet may be suggested for your dog. Don’t give treats to your dog, especially those with sodium chloride, without discussing with your veterinarian. Stick with the diet recommended for your dog until complete recovery is achieved.

Most dogs with hypernatremia without any underlying disease respond well and prognosis is excellent. However, animals with an underlying disease responsible for electrolyte derangements, prognosis depends on treatment of the disease along with correction of electrolyte imbalances.

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