Parathyroid disease is caused by malfunctioning parathyroid glands. If the parathyroid glands are overactive, the condition is called hyperparathyroidism and results in high levels of calcium in the blood and urine. Roughly half of all cases of hyperparathyroidism cause symptoms that are very vague or cause no symptoms at all, according to the University of Maryland Medical Center. In other cases, the high levels of calcium can cause a variety of symptoms.

Aches, Pains and Weakness

The high levels of calcium can result in many different types of pain and weakness in the body, such as muscle, joint, back and abdominal pain, explains Medline Plus. Severe muscle weakness and fatigue may also occur. Because hyperparathyroidism sends signals to the bones to release calcium into the bloodstream, bones can weaken, leading to osteoporosis and an increased risk of bone fracture.

Nausea and Vomiting

In more severe cases of hyperparathyroidism, nausea, vomiting and loss of appetite may develop, the National Endocrine and Metabolic Diseases Information Service reports. In some cases, constipation may also occur. Certain individuals with hyperparathyroidism may experience increased thirst, as well as increased urine output.

Depression

Hyperparathyroidism can also affect mood and personality, leading to conditions such as depression, anxiety or irritability, the University of Maryland Medical Center notes. Some patients may also suffer from memory loss and personality changes. In severe cases, a patient may become comatose.

Additional Symptoms

Dry, itchy skin is another symptom that may develop as a result of hyperparathyroidism. The high levels of calcium and phosphorus in the blood also increase the risk of kidney stones. Left untreated, long-term cases of hyperparathyroidism can lead to a decrease in height.