Sodium Deficiency in Dogs and Cats (Hypothermia): Understanding Causes, Symptoms, and Treatments

This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed on November 15, 2024

What Is Sodium Deficiency in Dogs and Cats?

Sodium deficiency, also known as hyponatremia, occurs when the sodium concentration in the body becomes too low. This condition presents in two ways:

• Slow-developing sodium deficiency: Symptoms may be mild or go unnoticed.
• Rapid-onset sodium deficiency: This form is more severe and can lead to life-threatening neurological symptoms.

Interestingly, the term “sodium deficiency” can be misleading, as it doesn’t typically mean a lack of sodium in the diet. In most cases, the intake of sodium chloride (salt) is normal. The problem arises when sodium becomes excessively diluted within the body.

To understand this, imagine mixing orange cordial with water. A small amount of cordial in a regular-sized glass creates a balanced drink. But if you dilute the same amount of cordial in a large bucket of water, the drink becomes overly weak. Similarly, in sodium deficiency, diluted sodium in the body affects fluids in critical areas like the brain, potentially leading to severe nerve-related symptoms.

Symptoms of Sodium Deficiency in Dogs and Cats

Sodium deficiency in dogs and cats can result in a range of symptoms, depending on how quickly sodium levels drop:

• Gradual sodium deficiency often shows no visible signs, as the body adjusts to protect the brain.
• Rapid sodium level drops can result in life-threatening symptoms, including:
  • Lethargy
  • Mental dullness
  • Unresponsiveness
  • Head tremors
  • Seizures
  • Coma
  • Death
• Sodium deficiency is often caused by underlying health issues. For example, heart disease in dogs can lead to additional symptoms, such as a persistent cough.

Recognizing these signs early is critical for effective treatment and addressing the underlying cause.

Causes of Sodium Deficiency in Dogs and Cats

The development of sodium deficiency in dogs and cats is typically linked to underlying conditions that dilute the blood or cause sodium loss.

• Psychogenic polydipsia: This psychological condition, where pets compulsively drink excessive amounts of water, dilutes the blood and lowers sodium levels. Learn more about psychogenic polydipsia.
• Medications: Certain drugs can lead to fluid retention, including:
  • Chemotherapy drugs
  • Barbiturates
  • Tricyclic antidepressants
• Diseases that cause fluid retention, such as:
  • An underactive thyroid
  • Congestive heart failure
  • Nephrotic syndrome
  • Addison’s disease
  • Kidney failure

Another potential cause of hyponatremia is the overly rapid administration of intravenous fluids, which can dangerously dilute sodium levels.

On the other hand, sodium loss from the body can also lead to hyponatremia. This can occur through:

• Severe vomiting
• Loss of sodium through the skin from burns
• Loss into a body cavity, such as with peritonitis or fluid accumulation around the lungs

Understanding the underlying cause is crucial for accurate diagnosis and effective treatment of sodium deficiency.

Diagnosis of Sodium Deficiency in Dogs and Cats

Diagnosing sodium deficiency in dogs and cats involves conducting blood tests to evaluate electrolyte levels, including sodium.

If sodium concentration is low, veterinarians often screen for underlying conditions, such as hypothyroidism or Addison’s disease. In some cases, advanced imaging, like CT or MRI scans, may be required to identify other potential causes of central nervous system (CNS) disease, such as meningitis or tumors.

Treatment of Sodium Deficiency in Dogs and Cats

The treatment approach depends on the severity of symptoms:

• Severe cases with neurological symptoms: Pets experiencing seizures require immediate intervention. Diazepam is commonly administered to control seizures quickly. Once stabilized, blood sodium concentrations are raised gradually using intravenous sodium solutions. This slow approach is essential to avoid brain shock, which can be equally dangerous.
• Mild cases with no symptoms: Treating the underlying condition is key.
  • For dogs with hypothyroidism, oral thyroid supplements can restore sodium balance.
  • Cats with nephrotic syndrome may require a high-protein diet and diuretics to address fluid retention.

Preventing Sodium Deficiency in Dogs and Cats

Sodium deficiency in dogs and cats often results from underlying diseases. These conditions typically present with symptoms such as:

• Increased thirst
• Poor appetite
• Changes in body shape

The best way to prevent complications like hyponatremia is by seeking prompt veterinary care as soon as you notice signs of illness in your pet. Early diagnosis and treatment of the underlying condition can help maintain normal sodium levels and protect your pet’s overall health.

Frequently Asked Questions (FAQ)

References

• “Hyponatremia — a quick reference.” De Morais & DiBartola. Vet Clin Small Animal Practice, 38: 491–495.
• Fluid, Electrolytes and Acid-base Disorders in Small Animal Practice. Publisher: Elsevier.