Hyperparathyroidism (Overactive Parathyroid Glands) in Dogs
- Occurrence: rarer
- Location of disease: Abdomen/pelvis
When to visit the vet?
Non-urgent see a veterinarian within 2–3 days
If the condition worsens / symptoms persist, consult a veterinarian.
Definition
Hyperparathyroidism in dogs is a condition in which the parathyroid glands produce too much parathyroid hormone (PTH), leading to elevated blood calcium levels.
The most important facts at a glance
Hyperparathyroidism in dogs is a condition in which the parathyroid glands produce too much parathyroid hormone (PTH), leading to elevated blood calcium levels. This can cause serious health problems. Primary hyperparathyroidism is often caused by a benign parathyroid adenoma, while secondary hyperparathyroidism can result from chronic kidney disease or diet-related imbalances. Symptoms include Lethargy, increased thirst and Urinary urgency, Weight loss, and Nausea. Diagnosis is made through clinical examinations, blood tests to check calcium and phosphorus levels, and imaging to detect Tumors. Treatment varies depending on the cause: primary hyperparathyroidism often requires surgical removal of the affected tissue, while secondary hyperparathyroidism involves treating the underlying condition. For acute hypercalcemia, fluid therapy may be necessary. The prognosis depends on the cause and stage of the disease, with early diagnosis and treatment improving the chances. There is no specific prevention for primary hyperparathyroidism, but regular veterinary check-ups can help detect problems early. For secondary hyperparathyroidism, a balanced diet is important. Research focuses on genetic predispositions, improved diagnostic methods, and new therapeutic approaches, including the role of diet and the microbiome in the course of the disease.
Causes
The parathyroid glands are small glands located near the thyroid gland. They are essential for regulating blood calcium levels by producing parathyroid hormone (PTH). PTH raises blood calcium levels by promoting calcium absorption in the intestines, stimulating the release of calcium from bones, and reducing calcium excretion via the kidneys. Overproduction of PTH leads to hypercalcemia, a condition that can cause serious health problems in dogs.
Primary hyperparathyroidism is usually caused by an adenoma, a benign growth of the parathyroid glands. These tumors lead to uncontrolled production of PTH. More rarely, parathyroid carcinomas are the cause, which can also lead to overproduction of PTH.
Secondary hyperparathyroidism can be caused by chronic kidney disease or by diet-related imbalances such as a calcium deficiency or an excess of phosphorus. In chronic kidney disease, the kidneys’ ability to excrete phosphorus is impaired, leading to an imbalance of calcium and phosphorus and stimulating the parathyroid glands to produce more PTH.
Symptoms
Symptoms of hyperparathyroidism in dogs can be subtle and develop gradually. One of the most common symptoms is polyuria and polydipsia, meaning the dog urinates more than normal and is thirstier than usual. This happens due to the effect of elevated calcium on kidney function.
Other signs may include loss of appetite, Vomiting, weakness, and Lethargy. Some dogs also show behavioral changes or seem depressed. In severe cases, Muscle weakness, tremors, and even bone pain can occur, as the body draws calcium from the bones to maintain the high blood level.
Over the long term, hypercalcemia can lead to calcification of soft tissues and organs, especially the kidneys, impairing kidney function and ultimately leading to renal failure.
Diagnosis
Diagnosis of hyperparathyroidism usually begins with a thorough clinical examination and a detailed medical history. The veterinarian will ask whether there have been changes in drinking and urination habits and whether other symptoms such as Vomiting or loss of appetite have occurred.
Blood tests are essential to check calcium levels. Elevated blood calcium is a strong indication of hyperparathyroidism. Phosphorus levels are also measured, as an imbalance between calcium and phosphorus can indicate problems with the parathyroid glands.
A specific test to determine the PTH level in the blood can be performed to confirm the diagnosis. Imaging procedures such as ultrasound or X-rays can help identify tumors or abnormalities in the parathyroid glands.
Therapy
Treatment for hyperparathyroidism depends on the cause. In primary hyperparathyroidism caused by an adenoma, surgical removal of the affected tissue is the most common and effective therapy. This surgery requires careful postoperative monitoring of calcium levels, as they can drop suddenly after removal.
In secondary hyperparathyroidism caused by kidney disease, treatment focuses on the underlying condition. A special diet with reduced phosphorus and the use of phosphate binders can help restore the calcium–phosphorus balance.
In acute cases of hypercalcemia, intravenous fluid therapy may be necessary to quickly lower calcium levels. Medications such as calcitonin or bisphosphonates may also be used to control calcium levels.
Prognosis and follow-up care
The prognosis for hyperparathyroidism depends on the cause and the stage of the disease. With timely diagnosis and treatment, the prognosis for dogs with primary hyperparathyroidism is usually good, especially if the adenoma can be successfully removed.
In secondary hyperparathyroidism caused by chronic kidney disease, the prognosis is more variable and depends on the progression of the kidney disease. Early intervention can slow progression and improve the dog’s quality of life.
Prevention
There is no specific prevention for primary hyperparathyroidism, as the development of parathyroid 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 balanced calcium and phosphorus levels can help minimize the risk of imbalances. In dogs with known kidney problems, regular monitoring of kidney values and electrolyte balance is important.
Outlook on current research
Current research on hyperparathyroidism in dogs focuses on understanding genetic predisposition and the molecular mechanisms that lead to this condition. Researchers are investigating how genetic markers in certain dog breeds could influence susceptibility to hyperparathyroidism. These studies aim to develop preventive measures and improve early diagnosis options through genetic testing.
Another important area of research is improving diagnostic methods. Scientists are working on developing non-invasive techniques to better assess parathyroid gland function. These techniques include advanced imaging methods such as high-resolution ultrasound 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 developing medications that specifically target the overproduction of parathyroid hormone. This includes research into calcimimetics, which increase the parathyroid glands’ sensitivity to calcium and could regulate hormone production.
Studying the effects of environmental influences and diet on the development of hyperparathyroidism is another aspect of current research. Scientists are trying to understand how factors such as nutritional deficiencies—especially related to calcium and vitamin D—could increase the risk of the disease. These findings could lead to recommendations for dietary adjustments that reduce the risk of developing this condition.
Finally, the role of the microbiome in relation to hyperparathyroidism is also being studied. Researchers are interested in how the intestinal flora / gut microbiota could influence calcium metabolism and parathyroid health. These insights could open up new perspectives for treatment and prevention by highlighting the importance of a healthy intestinal flora / gut microbiota for the dog’s overall health.