What are the early signs of hyponatremia?

Common early signs include dull demeanor, lethargy, reduced appetite, repeated vomiting, and an unsteady gait. Seek emergency care immediately if seizures or unresponsiveness develop.

What tests will the vet run?

The vet will typically order a blood electrolyte and biochemistry panel plus urinalysis, and may arrange X-rays or advanced imaging as needed to identify the cause.

What can I observe at home to help with the diagnosis?

Record the time of onset, number of vomiting episodes, changes in food and water intake, and urination or defecation patterns; filming symptoms on your phone gives the vet valuable information for a quicker assessment.

How long does follow-up last after treatment?

Follow-up frequency depends on the underlying cause and severity. After acute stabilization, blood tests to monitor electrolytes are usually needed over days to weeks; long-term causes may require periodic check-ups and specialist evaluation.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Hyponatremia in Dogs & Cats: Neurological Signs, Blood Tests & Treatment [2025]

Hyponatremia can be caused by vomiting, adrenal insufficiency, or water intoxication. In severe cases it leads to cerebral edema and seizures. Correction must be carefully paced — raising sodium too quickly can cause neurological damage.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ACVIM, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

•Persistent or repeated seizures that cannot be stopped
•Suddenly becoming completely unresponsive or comatose
•Slowed, labored, or irregular breathing

Arrange a clinic visit as soon as possible (within 24-72 hours)

•Markedly low energy and reduced activity
•Repeated vomiting or prolonged drowsiness
•Unsteady walking or a marked change with limb weakness

01What Symptoms Indicate Something Is Wrong?

Hyponatremia commonly causes changes in mental state and neurological function; closely monitor for any changes in behavior or consciousness.

Dull demeanor, lethargy, or a noticeable drop in energy
Weakness, slow movement, or an unsteady gait
Repeated vomiting, persistent nausea, or reduced appetite
Seizures or involuntary muscle twitching
Confusion, sluggish responses, or loss of consciousness

Seek emergency care immediately if you notice the following symptoms:

⚠️ Seek emergency care immediately for continuous or repeated seizures
⚠️ Seek emergency care for sudden collapse or complete unresponsiveness

02How to Assess Abnormalities at Home: Key Observations and When to Go to the ER

Recording key changes at home before the vet visit helps your veterinarian make a faster assessment and prioritize treatment.

Note your pet's mental state, frequency of lethargy, and periods of alertness
Write down the number of vomiting episodes, the time each occurred, and the appearance of the vomit
Track changes in appetite, water intake, and food consumption
Observe and record the frequency and character of urination and defecation
Record a video of the symptoms on your phone and note the time of onset
If symptoms worsen, arrange a clinic visit or emergency appointment promptly

03How Will the Vet Diagnose This? Common Diagnostic Tests

At the clinic, a physical examination combined with blood and imaging tests will be used to identify the underlying cause of the electrolyte imbalance and assess its severity.

Full physical and neurological examination to assess consciousness and reflexes

Blood work including a complete blood count and electrolyte panel (serum sodium)

Biochemistry panel to evaluate liver and kidney function and overall metabolic status

Urinalysis to assess kidney function and urine concentrating ability

X-rays or advanced imaging (CT/MRI) if needed for further evaluation

04How Is Hyponatremia Treated and Managed? Medications, Diet, and Care Guide

Treatment includes acute stabilization and long-term management targeting the underlying cause, with regular blood tests to monitor electrolytes and biochemical values.

In the acute phase, fluid therapy and electrolyte correction may be used to stabilize your pet
Ongoing treatment or medication will be directed at the underlying cause of the hyponatremia
Return for scheduled blood draws as instructed to monitor sodium levels and biochemical changes
Adjust diet and fluid management according to your veterinarian's recommendations
Continue monitoring at home for changes in mental state, vomiting, and seizures, and keep a record
If needed, referral to a specialist or a facility with advanced imaging may be recommended

05What to Prepare Before the Vet Visit: Key Information to Help Your Vet Diagnose Quickly

Note when symptoms first appeared and how they have progressed

List any recent changes in food or water intake

Bring a list of all current medications, supplements, and prescriptions

Save videos or photos of vomiting or seizure episodes for review

If possible, bring a fresh urine sample or any recent test results

Call ahead to make an appointment and describe the urgency of the symptoms

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.