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Hyperparathyroidism (Overactive Parathyroid Glands) in Dogs

Occurrence: rarer
Location of illness: Abdomen/pelvis

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Hyperparathyroidism in dogs is a condition in which the parathyroid glands produce excessive parathyroid hormoneParathyroid hormone, also called parathyrin or parathyroid hormone (PTH), is a hormone produced by the parathyroid glands. It plays an essential role in regulating calcium and phosphate levels in the blood. (PTH), leading to elevated blood calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels.

The most important facts at a glance

Hyperparathyroidism in dogs is a condition in which the parathyroid glands produce too much parathyroid hormoneParathyroid hormone, also called parathyrin or parathyroid hormone (PTH), is a hormone produced by the parathyroid glands. It plays an essential role in regulating calcium and phosphate levels in the blood. (PTH), leading to elevated calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels in the blood. This can cause serious health problems. PrimaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. hyperparathyroidism is often caused by a benignBenign refers to a non-invasive, non-serious condition that is not life-threatening. In medicine, the term is often used to describe benign tumors that do not metastasize, meaning they do not form secondary tumors. adenoma of the parathyroid glands, while secondary hyperparathyroidism can result from chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. kidney disease or nutritional imbalances. Symptoms include Lethargy, increased thirst and Urinary urgency, Weight loss, and Nausea. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through clinical examinations, blood tests to check calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and phosphorusPhosphorus is a vital mineral found in bones and teeth, playing a central role in energy metabolism and DNA. A balanced phosphorus to calcium ratio is essential for the health of dogs and cats. levels, and imaging procedures to detect Tumors. Treatment varies depending on the cause: PrimaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. hyperparathyroidism often requires surgical removal of the affected tissue, while secondary hyperparathyroidism treats the underlying condition. Fluid therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. may be necessary for acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. hypercalcemia. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. depends on the cause and stage of the disease, with early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment improving the chances. There is no specific preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. for primaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. hyperparathyroidism, but regular veterinary check-ups can help detect problems early. A balanced diet is important for secondary hyperparathyroidism. Research focuses on genetic predispositions, improved diagnostic procedures, and new therapeutic approaches, including the role of nutrition and microbiome in the course of the disease.

Causes

The parathyroid glands are small glands located near the thyroid gland. They are crucial for regulating blood calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels by producing parathyroid hormoneParathyroid hormone, also called parathyrin or parathyroid hormone (PTH), is a hormone produced by the parathyroid glands. It plays an essential role in regulating calcium and phosphate levels in the blood. (PTH). PTH increases blood calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels by promoting calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. absorptionAbsorption refers to the uptake of substances by living cells or tissues. In the context of veterinary medicine, it often refers to the absorption of nutrients, drugs, or toxins from the digestive tract into the bloodstream. in the intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients., stimulating calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. release from bones, and reducing calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. excretion by the kidneys. Overproduction of PTH leads to hypercalcemia, a condition that can cause serious health problems in dogs.

PrimaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. hyperparathyroidism is usually due to an adenoma, a benignBenign refers to a non-invasive, non-serious condition that is not life-threatening. In medicine, the term is often used to describe benign tumors that do not metastasize, meaning they do not form secondary tumors. tumorA tumor is an abnormal growth of tissue that can be benign or malignant. Tumors can develop in any part of the body and affect various functions. of the parathyroid glands. These Tumors lead to uncontrolled production of PTH. Less commonly, parathyroid carcinomas are the cause, which also lead to overproduction of PTH.

Secondary hyperparathyroidism can be caused by chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. kidney disease or nutritional imbalances such as a deficiencyDeficiency means a lack or absence of a necessary substance required for normal bodily functions or health, such as vitamins, minerals, or hormones. of calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. or an excess of phosphorusPhosphorus is a vital mineral found in bones and teeth, playing a central role in energy metabolism and DNA. A balanced phosphorus to calcium ratio is essential for the health of dogs and cats.. In chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. kidney disease, the kidneys’ ability to excrete phosphorusPhosphorus is a vital mineral found in bones and teeth, playing a central role in energy metabolism and DNA. A balanced phosphorus to calcium ratio is essential for the health of dogs and cats. is impaired, leading to an imbalanceImbalance refers to an imbalance or disruption of normal function or composition in the body, which can lead to health problems. of calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and phosphorusPhosphorus is a vital mineral found in bones and teeth, playing a central role in energy metabolism and DNA. A balanced phosphorus to calcium ratio is essential for the health of dogs and cats. and stimulating the parathyroid glands to produce more PTH.

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

The symptoms of hyperparathyroidism in dogs can be subtle and develop gradually. One of the most common symptoms is polyuriaPolyuria refers to a significantly increased urine output. It can be a symptom of various diseases, including diabetes mellitus, kidney disease, and hormonal disorders. and polydipsiaPolydipsia refers to an increased feeling of thirst and increased fluid intake. It can be a symptom of various diseases, including diabetes mellitus and kidney disease., meaning the dog urinates more than normal and has increased thirst. This occurs due to the effect of increased calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. on kidney function.

Other signs may include loss of appetite, Vomiting, weakness, and Lethargy. Some dogs also show changes in behavior or are depressed. In severe cases, Muscle weakness, tremors, and even bone pain can occur as the body dissolves calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. from the bones to maintain high blood levels.

In the long term, hypercalcemia can lead to calcified soft tissues and organs, especially the kidneys, leading to impaired kidney function and ultimately kidney failureRenal failure is a condition in which the kidneys can no longer adequately perform their function of filtering and excreting waste products from the blood. It can be acute or chronic and requires immediate medical treatment..

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of hyperparathyroidism usually begins with a thorough clinical examination and a detailed history. The veterinarian will ask if there are changes in drinking and urinary habits and if other symptoms such as Vomiting or loss of appetite have occurred.

Blood tests are crucial to check calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels. An elevated calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. level in the blood is a strong indicationIndication refers to a valid reason or rationale for using a specific treatment, medication, or medical procedure. It is based on the diagnosis and the patient's clinical condition. of hyperparathyroidism. PhosphorusPhosphorus is a vital mineral found in bones and teeth, playing a central role in energy metabolism and DNA. A balanced phosphorus to calcium ratio is essential for the health of dogs and cats. levels are also measured, as an imbalanceImbalance refers to an imbalance or disruption of normal function or composition in the body, which can lead to health problems. between calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and phosphorusPhosphorus is a vital mineral found in bones and teeth, playing a central role in energy metabolism and DNA. A balanced phosphorus to calcium ratio is essential for the health of dogs and cats. may indicate problems with the parathyroid glands.

A specific test to determine the PTH level in the blood can be performed to confirm the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients.. Imaging procedures such as ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. or X-rays can help identify Tumors or abnormalities in the parathyroid glands.

Therapy

The treatment of hyperparathyroidism depends on the cause. For primaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. hyperparathyroidism caused by an adenoma, surgical removal of the affected tissue is the most common and effective therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions.. This surgery requires careful postoperativePostoperative refers to the time after a surgical operation. This phase includes recovery and the management of possible complications after the procedure. monitoring of calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels, as a sudden drop can occur after removal.

In secondary hyperparathyroidism caused by kidney disease, treatment focuses on the underlying condition. A special diet with reduced phosphorusPhosphorus is a vital mineral found in bones and teeth, playing a central role in energy metabolism and DNA. A balanced phosphorus to calcium ratio is essential for the health of dogs and cats. content and the administration of phosphate binders can help restore the calcium-phosphorus balance.

In acute cases of hypercalcemia, intravenous fluid therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. may be necessary to rapidly lower calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels. Medications such as calcitonin or bisphosphonates can also be used to control calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels.

Prognosis and follow-up care

The prognosis for hyperparathyroidism depends on the cause and stage of the disease. With timely diagnosis and treatment, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. for dogs with primary hyperparathyroidism is generally good, especially if the adenoma can be successfully removed.

In secondary hyperparathyroidism caused by chronic kidney disease, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is more variable and depends on the progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. of the kidney disease. Early intervention can slow the progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. of the disease and improve the dog’s quality of life.

Prevention

There is no specific preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. for primaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. hyperparathyroidism, as the development of parathyroid gland Tumors cannot be controlled. However, regular veterinary check-ups can help detect potential problems early.

To prevent secondary hyperparathyroidism, especially in dogs with kidney disease, a balanced diet is crucial. A diet with a balanced calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and phosphorusPhosphorus is a vital mineral found in bones and teeth, playing a central role in energy metabolism and DNA. A balanced phosphorus to calcium ratio is essential for the health of dogs and cats. content can help minimize the risk of imbalances. In dogs with known kidney problems, regular monitoring of kidney values and electrolyte balanceThe electrolyte balance refers to the balance of electrolytes in the body, which is essential for many physiological processes. Disturbances in the electrolyte balance can lead to serious health problems. is important.

Outlook on current research

Current research in the field of hyperparathyroidism in dogs focuses on understanding the genetic predisposition and molecular mechanisms that lead to this disease. Researchers are investigating how genetic markers in certain dog breeds might influence susceptibility to hyperparathyroidism. These studies aim to develop preventive measures and improve early diagnostic options through genetic testing.

Another significant area of research is the improvement of diagnostic procedures. Scientists are working on developing non-invasive techniques to better assess the function of the parathyroid glands. These techniques include advanced imaging procedures such as high-resolution ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. and specialized blood tests that can detect specific hormonal changes.

In addition, research into therapeutic approaches is of great importance. New treatment strategies focus on the development of drugs that specifically target the overproduction of parathyroid hormoneParathyroid hormone, also called parathyrin or parathyroid hormone (PTH), is a hormone produced by the parathyroid glands. It plays an essential role in regulating calcium and phosphate levels in the blood.. This includes the exploration of calcimimetics, which could increase the sensitivity of the parathyroid glands to calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and thus regulate hormoneHormones are chemical messengers produced by endocrine glands and released into the bloodstream to affect specific cells or organs in the body. They regulate numerous bodily functions, including growth, metabolism, and reproduction. production.

The study of the effects of environmental influences and nutrition on the development of hyperparathyroidism is another aspect of current research. Scientists are trying to understand how factors such as nutritional deficiencies, especially in terms of calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and vitaminVitamins are organic compounds that are necessary in small amounts for the normal growth, development, and physiological function of the body. Vitamins must mostly be obtained through food, as the body cannot produce them or not in sufficient quantities. D, could increase the risk for the disease. These findings could lead to recommendations for dietary adjustments that reduce the risk of developing this disease.

Finally, the role of the microbiome in the context of hyperparathyroidism is also being investigated. Researchers are interested in how the intestinalIntestinal refers to the intestine, the part of the digestive tract that extends from the stomach to the anus. Intestinal diseases affect the small and/or large intestine. flora could influence calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. metabolism and the health of the parathyroid glands. These findings could open up new perspectives for the treatment and preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of the disease by highlighting the importance of a healthy intestinalIntestinal refers to the intestine, the part of the digestive tract that extends from the stomach to the anus. Intestinal diseases affect the small and/or large intestine. flora for the overall health of the dog.

Frequently asked questions (FAQs)

What is Hyperparathyroidism in Dogs? Hyperparathyroidism is a condition in which the parathyroid glands produce excessive parathyroid hormoneParathyroid hormone, also called parathyrin or parathyroid hormone (PTH), is a hormone produced by the parathyroid glands. It plays an essential role in regulating calcium and phosphate levels in the blood. (PTH). This hormoneHormones are chemical messengers produced by endocrine glands and released into the bloodstream to affect specific cells or organs in the body. They regulate numerous bodily functions, including growth, metabolism, and reproduction. regulates calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and phosphate metabolism in the body. Overproduction often leads to elevated calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels in the blood, which can cause various health problems.
What symptoms are typical of hyperparathyroidism in dogs? The most common symptoms include increased thirst and frequent urination, loss of appetite, Vomiting, Lethargy, and weakness. In severe cases, bone pain or fractures may also occur.
What causes hyperparathyroidism in dogs? The most common cause is a benignBenign refers to a non-invasive, non-serious condition that is not life-threatening. In medicine, the term is often used to describe benign tumors that do not metastasize, meaning they do not form secondary tumors. tumorA tumor is an abnormal growth of tissue that can be benign or malignant. Tumors can develop in any part of the body and affect various functions. of the parathyroid glands, called an adenoma. Other causes may be genetic factors or rarer types of Tumors. Secondary hyperparathyroidism can be triggered by chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. kidney disease or nutritional problems.
How is hyperparathyroidism diagnosed in dogs? DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is usually made through a combination of blood tests that measure calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and parathyroid hormoneParathyroid hormone, also called parathyrin or parathyroid hormone (PTH), is a hormone produced by the parathyroid glands. It plays an essential role in regulating calcium and phosphate levels in the blood. levels, as well as imaging procedures such as ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. to examine the parathyroid glands.
What treatment options are available for hyperparathyroidism in dogs? Treatment depends on the cause. In the case of a TumorA tumor is an abnormal growth of tissue that can be benign or malignant. Tumors can develop in any part of the body and affect various functions., surgical removal of the affected parathyroid gland may be necessary. Medications can be used to regulate calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. levels. In some cases, dietary adjustments are necessary.
Can hyperparathyroidism be cured in dogs? If the cause is a benignBenign refers to a non-invasive, non-serious condition that is not life-threatening. In medicine, the term is often used to describe benign tumors that do not metastasize, meaning they do not form secondary tumors. TumorA tumor is an abnormal growth of tissue that can be benign or malignant. Tumors can develop in any part of the body and affect various functions. and it is successfully removed, the dog can be completely cured. For other causes or if the disease is related to chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. kidney disease, long-term treatment may be necessary.
How can I reduce the risk of hyperparathyroidism in my dog? A balanced diet with sufficient calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and vitaminVitamins are organic compounds that are necessary in small amounts for the normal growth, development, and physiological function of the body. Vitamins must mostly be obtained through food, as the body cannot produce them or not in sufficient quantities. D is important. Regular veterinary check-ups can help detect the disease early. Genetic counseling may also be useful for certain breeds.
Which breeds are most commonly affected by hyperparathyroidism? Certain breeds such as the Keeshond, Labrador Retriever, and German Shepherd Dog show a higher susceptibility. Genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. may play a role in these breeds.
Can a dog with hyperparathyroidism live a normal life? With the right treatment and monitoring, many dogs can live a normal and healthy life. However, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. depends on the severity of the disease and the underlying cause.
Are regular blood tests necessary for a dog with hyperparathyroidism? Yes, regular blood tests are important to monitor calciumCalcium is a mineral that is essential for building and maintaining strong bones and teeth. It also plays a role in blood coagulation, nerve transmission, and muscle contraction. and parathyroid hormoneParathyroid hormone, also called parathyrin or parathyroid hormone (PTH), is a hormone produced by the parathyroid glands. It plays an essential role in regulating calcium and phosphate levels in the blood. levels and ensure that treatment is effective. These tests also help to detect possible complications early.

When to visit the vet?

Non-urgent see a veterinarian within 2–3 days

If the condition worsens / symptoms persist, consult a veterinarian.