What is Hyponatremia and Hypernatremia in Cats

What is Hyponatremia and Hypernatremia in Cats

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hypernatremia in catshypernatremia in cats

Hyponatremia and hypernatremia in cats are disorders of blood sodium levels. The term hyponatremia is used to describe low concentrations of sodium in the blood and hypernatremia is used to describe high concentrations of sodium in the blood. These conditions have different causes and treatments.

Sodium is critical to all body functions including blood pressure maintenance, acid/base balance, and preservation of blood volume.

Below, we will provide information about the symptoms of, diagnostic tests for, causes and treatment of hyponatremia and hypernatremia in cats.

Hyponatremia in Cats

Sodium is an essential component of a fluid makeup and is extremely important in its relationship with fluid balance. A common line used to help veterinary students understand the interaction of sodium on body fluids is “Where sodium goes…water follows”. Normal sodium blood levels is critical to maintaining a normal body fluid balance.

Changes in sodium levels can occur slowly or quickly which can cause a variety of life-threatening symptoms. The faster the change in sodium levels the more severe the clinical signs because the body has not had time to adjust.

Hyponatremia is a symptom and many diseases can result in low sodium levels. Hyponatremia has various effects throughout the body. Hyponatremia can affect any age, breed or sex of cat.

Causes of Hyponatremia in Cats

Causes of hyponatremia in cats may include:

  • Hyperglycemia (high blood sugar levels can cause increased blood sodium levels)
  • Dehydration
  • Medication administration such as from mannitol
  • Specific types of intravenous fluids administration such as hypotonic fluids
  • Fluid overload (too much fluid in the body)
  • Congestive heart failure
  • Sodium losses from such vomiting, diarrhea, excessive urinations
  • Polydipsia which is a disease of excessive thirst
  • Liver failure

Symptoms of Hyponatremia in Cats

Signs of a low blood sodium levels in cats may include:

  • Coma
  • Confusion
  • Diarrhea
  • Dullness
  • Head pressing Cat Head Pressing: What You Need to Know
  • Head tremors
  • Inappropriate behavior
  • Labored respirations (dyspnea)
  • Lethargy
  • Nausea/vomiting
  • Seizures
  • Weakness
  • Severe neurological signs may occur when the serum sodium level falls below 110 to 115 mEq/L in cats.

Diagnostic Test for Hyponatremia in Cats

Blood tests will diagnose low blood sodium levels.

  • The biochemical profile reveals low blood sodium levels which confirms the diagnosis of hyponatremia.
  • Other abnormalities may also be detected such as kidney failure, diabetes or other diseases.
  • The complete blood count may be normal or reveal abnormalities from the primary problem.
  • The urinalysis may reveal dilute urine associated with kidney failure.

Once a low blood sodium is detected, it is critical to determine the underlying cause to provide the most effective treatment.

Treatment of Hyponatremia in Cats

Treatment will vary depending on the severity of the clinical signs, the degree of hyponatremia, and the underlying cause.

  • Cats dehydrated with low blood sodium may be treated with intravenous fluids therapy that contains sodium.
  • Cats with excessive fluid in the blood can be treated with diuretic medications and restriction of sodium (salt). Rapid intravenous administration can lead to severe electrolyte disturbances and may result in death.
  • Careful monitoring of hydration status and sodium concentrations is important to avoid overcorrection.
  • If the low sodium is severe, cats are hospitalized and given therapy over the source of hours to days. Cats often also require treatment for the underlying cause of the hyponatremia. Many cats respond favorably within 2 to 5 days but complete recovery may take several weeks.

Prevention of Hyponatremia in Cats

Cats with hyponatremia should be monitored for relapse or development of other signs. Many cats have underlying disease, such as kidney failure, and may need additional treatment.

Hypernatremia in Cats

Sodium is an essential component of a fluid makeup and is extremely important in its relationship with fluid balance. Changes in sodium levels can occur slowly or quickly which can cause a variety of life-threatening symptoms. Sodium is often associated with chloride and abnormalities in sodium levels often also causes abnormalities in chloride blood levels. Hypernatremia can affect any age, breed or sex of cat. Hypernatremia is defined by serum sodium concentrations over 165 mEq/L in cats.

Hypernatremia can be caused by loss of water through the kidneys or gastrointestinal tract or from low water intake.

Symptoms of Hypernatremia in Cats

Signs of high blood sodium levels may include:

  • Increased thirst (also known as polydipsia)
  • Confusion
  • Disorientation
  • Cat Head Pressing: What You Need to Know
  • Coma
  • Seizures
  • Serum sodium levels over 180 mEq/L can cause severe neurological symptoms.

Diagnostic Test for Hypernatremia in Cats

Blood tests will diagnose high blood sodium levels.

  • The biochemical profile reveals high blood sodium levels and confirms the diagnosis. Other
  • abnormalities may also be detected such as kidney failure, diabetes or other diseases.
  • The complete blood count may be normal or reveal abnormalities from the primary problem.
  • The urinalysis may reveal dilute urine associated with diabetes and a potential secondary infection.

Causes of Hypernatremia in Cats

Causes of high blood sodium may include:

  • Decreased water intake
  • High sodium intake
  • Increased urinations causing water loss (such as with diabetes)
  • Intravenous fluid therapy containing high levels of sodium
  • Losses of sodium through vomiting and/or diarrhea

Treatment of Hypernatremia in Cats

Treatment will vary depending on the severity of the clinical signs, the degree of hypernatremia, and the underlying cause. Once diagnosed, cats are treated with intravenous fluids therapy balanced to provide hydration but lower levels of sodium. The fluid chosen will depend on if the cat is also dehydrated. Fluid options may include Lactated Ringers Solution (LRS), Normal Saline (0.9% NS), or 5% dextrose (D5%W). Learn more about Fluid Therapy.

Rapid correct of high sodium levels can cause pulmonary edema and result in death. Careful monitoring of hydration status and sodium concentrations are critical to avoid overcorrection.

Prevention of Hypernatremia in Cats

Feeding a high quality diet and ensuring availability of fresh clean water at all times Is important to the health of your cat.

Reference Articles about Hypernatremia and Hyponatremia in Cats

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