Excess Sodium in the Blood in Cats

Your veterinarian may refer to excess sodium in the blood of cats as hypernatremia. This electrolyte imbalance is commonly the result of excess sodium consumption, dehydration, an underlying acute condition, or chronic disease.

Excess sodium in the blood of cats, or hypernatremia, is an electrolyte imbalance. Since sodium is an electrolyte that plays a role in many body systems, your cat can begin to act strangely when sodium in the blood exceeds normal levels. If you suspect your cat suffers from excess sodium, contact a professional to prevent permanent brain damage, kidney damage or death.

Sodium is an important electrolyte that plays a major role in your cat's fluid balance. Sodium also regulates several organ systems and reactions integral to metabolism and brain function. As a result, excess sodium can manifest as a number of seemingly unrelated symptoms, such as:

• Excessive thirst
• Lethargy
• Poor appetite
• Weakness
• Seizures
• Behavior changes
• Internal bleeding

The symptoms of excess sodium in the blood of cats are common to many disease states. At the same time, depending on the underlying cause, your cat may exhibit a different set of symptoms as a result of this electrolyte imbalance. For this reason, it is extremely important to have a professional (i.e., your cat's veterinarian) perform diagnostic tests to confirm excess sodium in the blood is the true cause of your cat's symptoms.

Generally speaking, there are two major causes of excess sodium in the blood of cats, excess sodium intake and excess fluid loss. Within those categories, there are several major causes of feline hypernatremia. The most common are: 

• Salt Poisoning: Salt poisoning is simply the excessive intake of sodium-containing foods or liquids. Usually, salt poisoning is diagnosed in critically ill cats who are receiving concentrated intravenous fluids. This is not a very common cause of hypernatremia in cats, however. Much more common causes of feline hypernatremia are related to the production of excess sodium within your cat's body or the excessive loss of fluid.
• Dehydration: Simple dehydration is a common cause of excess sodium in the blood of cats. Sometimes cats become dehydrated due to a lack of available water. Other times, a hormonal imbalance prevents cats from feeling thirsty and seeking out water when they are dehydrated.
• Fluid losses: Cats can lose fluid in a number of ways. Panting, as with fever or overheating, can cause fluid loss through the respiratory tract. Diuretic use, common in cats with diabetes, may lead to fluid losses through the urinary tract. Diabetes insipidus, a hormonal imbalance, can also lead to excessive urinary fluid loss.
• Acute illness: Acute illness, especially bacterial infection leading to nausea, vomiting, and diarrhea, can lead to excessive gastrointestinal fluid losses.
• Chronic disease: Chronic kidney disease and diabetes can both lead to insufficient or excessive urination. This alters the ratio of sodium to fluid in the blood. Chronic kidney disease can also lead to sodium retention by the kidneys, which concentrates sodium in the blood.

If you have reason to believe your cat is suffering from excessive sodium, it is important to contact a veterinary professional immediately, as this condition can be severe and even fatal. You can expect a veterinarian to test for excess sodium in the blood of cats by drawing blood and performing a hematological assessment. If your cat's sodium level exceeds 160 milligrams per deciliter of blood, your veterinarian will diagnose your cat with hypernatremia.

Since the symptoms of excess sodium in the blood of cats are common, your veterinarian may also choose to perform a differential diagnosis to eliminate other conditions, such as other electrolyte fluctuations or hormone imbalances. 

Depending on what your veterinarian suspects is the cause of excess sodium in the blood of your cat, he or she may perform other tests. Urinalysis or thyroid hormone tests could be ordered to diagnose diabetes, chronic kidney disease or hormone imbalances. By pinpointing the exact cause of your cat's hypernatremia, your veterinarian will be better able to treat and prevent the recurrence of this condition.

Most cases of excess sodium in the blood of cats will be treated with intravenous (IV) fluids to replace water or dilute sodium in the blood. This is an incredibly safe, effective and conservative approach to restoring sodium balance. Any further course of treatment selected by your veterinarian will depend on the underlying cause of your cat's excessive sodium levels.

If salt poisoning is suspected to be the cause, it is likely that your veterinarian will administer intravenous fluids to restore sodium-water balance and offer counseling to prevent future episodes of excessive sodium intake. If a gastrointestinal infection leads to vomiting and diarrhea, antibiotics may be administered. Chronic disease, such as diabetes or chronic kidney disease, will require more extensive treatment and long-term management. 

Your veterinarian may counsel you on strategies to prevent this condition from affecting your cat in the future. Future management will depend on the cause of your cat's hypernatremia. If salt poisoning or dehydration are suspected to be the cause, a veterinarian might instruct you to make fresh water available to your cat at all times. Infection prevention, antibiotic treatment and medication management may also be discussed. If your cat's excessive sodium levels are the result of chronic disease, more extensive management specific to that disease state will be required.