Hypocalcemia in Dogs - Causes, Symptoms and Treatment
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Hypocalcemia is defined as insufficient blood calcium, i.e. the calcium levels in their blood are considered low. Calcium is a fundamental mineral in various bodily functions of dogs. These include blood coagulation, maintenance of bones and teeth, muscle and heart contraction, correct vision and the metabolism of various enzymes and hormones. Since a lack of calcium can harm these various bodily systems, symptoms of hypocalcemia can be varied and make diagnosis difficult.
At AnimalWised, we look at hypocalcemia in dogs more closely. We find out the causes, symptoms and treatment of low calcium in dogs, as well as what we can expect in terms of prognosis.
What is hypocalcemia in dogs?
Hypocalcemia is a relatively common problem in dogs. It has an estimated incidence rate of 9.6-16% in dogs. While the term is used to refer to a specific disorder (low levels of calcium in the blood), it has various causes and, consequently, various symptoms. Since calcium helps various bodily systems function, symptoms often arise due to said symptoms functioning improperly.
Why do dogs need calcium?
As stated above, calcium is important for maintaining various bodily functions. These include:
- Maintaining bones and teeth
- Muscle contraction (including pumping the heart)
- Blood coagulation
- Enzyme metabolism
- Hormone metabolism
- Fetal development
- Milk production in lactating females
When blood-calcium levels are measured in dogs, the veterinarian will use a total calcium test. This is measures both ‘free’ and ‘bound’ calcium:
- Bound calcium: attached to proteins.
- Free calcium: not attached to proteins, also known as ionized calcium.
Ionized calcium is determined by the function of parathyroid hormone (PTH), calcitonin and calcitriol. There are ionized calcium tests, but these are more difficult to administer. They are usually administered when a total calcium test proves in conclusive.
PTH increases calcium levels, promotes bone mobilization and renal reabsorption of calcium. It also increases calcitriol synthesis, allowing for better intestinal calcium absorption and renal and bone reabsorption of calcium. In hypocalcemia, the production of parathyroid hormone is stimulated, increasing calcitriol levels in the process and exerting a negative feedback on PTH synthesis.
Find out more information about foods for dogs which are high in calcium.
Symptoms of hypocalcemia in dogs
Only about 1% of calcium in a dog's body is present in blood. The majority is found in bones and teeth. However, as soon as the total concentration of calcium in a dog's blood is less than 7 mg/dl (or when an ionized calcium count is less than 0.8 mmol/l), symptoms will start to appear. The most common symptoms of hypocalcemia in dogs are the following:
- Muscle fasciculations (twitching)
- Stiffness when walking
- Appetite loss
- Decreased cardiac contractility and cardiac output
- Reduction of systemic and pulmonary vascular resistance
- Ventricular arrhythmias
Causes of hypocalcemia in dogs
Hypocalcemia in dogs can be a result of multiple health issues in dogs. They include:
- Hypoalbuminemia: the dog's body doesn't produce enough albumin protein, the protein responsible for fluidity in blood vessels.
- Kidney disease: both acute kidney injury or chronic kidney disease. Find out more about renal failure in dogs.
- Pancreatitis: inflammation of the pancreas which affects its functionality.
- Puerperal tetany: also known as milk fever in bitches. Occurs when the demand for calcium to be used in milk production after parturition is greater than the ability to mobilize it.
Less frequent causes of hypocalcemia in dogs include hypoparathyroidism, ethylene glycol intoxication, rhabdomyolysis and sodium bicarbonate or phosphate enemas.
Rare causes of hypercalcemia in dogs include errors in EDTA tubes (tubes for blood extraction), use of hydration fluids without calcium, intestinal malabsorption, hypomagnesemia, tumor lysis syndrome, secondary nutritional hyperparathyroidism or severe prolonged fasting.
Find out about other issues which can develop with our article on chronic diarrhea in dogs with intestinal malabsorption.
Diagnosis of hypocalcemia in dogs
The diagnosis of canine hypocalcemia is based on blood samples taken to measure calcium levels. It is important for the veterinarian to rule out the possibility of laboratory error, which can occur when analyzing a dog's blood test. This is often performed by ordering an ionized calcium test on top of the total calcium test.
Once we have confirmed the dog has low levels of calcium in their blood, we will need to determine the underlying cause. This may include further blood tests, as well as urinalysis, physical examination, medical history or diagnostic imaging tests, where necessary.
Hypocalcemia in dogs treatment
The treatment of hypocalcemia in dogs will depend on the underlying cause and its progression. Due to the severity of the symptoms of hypocalcemia in dogs and their rapid presentation, some dogs will need fluid therapy. This will be in the form of 10% calcium gluconate solution administered intravenously. This will be done by injecting 50-150 mg/kg weight of the dog in 20-30 minutes.
We should point out that calcium gluconate has the potential to be cardiotoxic, so it should always be administered with electrocardiographic monitoring. This will be used to detect possible bradycardia, ST-segment elevation, QT interval shortening, or other arrhythmias. The administration should be stopped for intervals of a few minutes, its evolution evaluated and a slower administration continued.
In chronic cases of hypocalcemia in dogs, they usually receive oral medication with calcium supplements or compounds, calcitriol or vitamin D derivatives. The latter promotes calcium absorption.
Thee underlying disease that is causing the hypocalcemia must be treated specifically to improve the patient's health and quality of life. It will also prevent calcium levels from falling further. Hypocalcemia in dogs must be diagnosed and treated by a professional. If you suspect your dog has a significant calcium deficiency, you cannot treat them at home. It is essential to determine the reason for this reduction and treat the underlying cause.
Low blood-calcium levels are not the only problem dogs can have with this mineral. When the dog's calcium levels are too high, they can develop other problems such as calcinosis cutis in dogs.
This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.
If you want to read similar articles to Hypocalcemia in Dogs - Causes, Symptoms and Treatment, we recommend you visit our Other health problems category.
- Cortadellas, O. Hypocalcemia in Dogs: Etiology and Management. Retrieved from: https://www.affinity-petcare.com/vetsandclinics/es/hipocalcemia-en-perro-etiologia-y-manejo
- Nelson, R.W. (2020). Small Animal Internal Medicine, 6th Edition. Assisi Group Biomedia, S. L.