High calcium levels in dogs are potentially life-threatening. Excess calcium, or hypercalcemia, is either the result of disease, or ingesting certain substances containing large amounts of calcium. Don't panic if your dog drank a lot of milk -- that's unlikely to cause hypercalcemia, although it may upset his stomach. Take your dog to the vet immediately if you know or suspect he consumed any sort of rodenticide, or ate a bottle of Vitamin D or similar supplements.
The Parathyroid Glands
Your dog's calcium levels are naturally controlled by his parathyroid glands, the number of which varies between individual canines but generally totals four. These tiny glands are either outside his thyroid glands in the neck, or inside the thyroid gland capsule. Parathyroid hormone, manufactured and stored in the glands, regulate whether calcium amounts in various parts of the body should increase or decrease. When they are out of whack, hypercalcemia can ensue.
Diseases Causing Hypercalcemia
Diseases causing hypercalcemia in canines include:
- Cancer, especially lymphoma
- Kidney failure
- Addison's disease, or hypoadrenocorticism
Signs and Symptoms
Symptoms of hypercalcemia include:
- polydipsia and polyuria -- increased drinking and urination
- appetite loss or vomiting
- high blood pressure
- kidney or bladder stones
- or shivering.
Dogs with only mildly elevated calcium levels may remain asymptomatic, but that doesn't mean they aren't sick. Dogs with mild hypercalcemia may later develop Addison's disease. Tell your vet about any supplements you give your pet.
Diagnosis and Treatment
Although many of the symptoms of hypercalcemia are common to various ailments, your vet can identify hypercalcemia by testing a sample of your dog's blood. She'll repeat the test 12 hours later, when your dog has fasted for that length of time.
Once hypercalcemia is confirmed, your dog will undergo various tests to determine the cause. These tests involve ascertaining the condition of his bones, urinary tract and gastrointestinal system. He may undergo X-rays and ultrasounds, and the vet may take a fine needle aspirate of his bone marrow or lymph nodes for cancer testing. Expect your dog to initially stay in the hospital for at least a day or so for testing and intravenous fluid therapy. Treatment depends on the underlying reason for the high level of blood calcium.