The oversecretion of PTH is due to a parathyroid adenoma, parathyroid hyperplasia, or rarely, a parathyroid carcinoma. This disease is often characterized by the quartet stones, bones, groans, and psychiatric overtones referring to the presence of kidney stones, hypercalcemia, constipation, and peptic ulcers, as well as depression, respectively.In a minority of cases, this occurs as part of a multiple endocrine neoplasia (MEN) syndrome, either type 1 (caused by a mutation in the gene MEN1) or type 2a (caused by a mutation in the gene RET), which is also associated with the adrenal tumor pheochromcytoma. Other mutations that have been linked to parathyroid neoplasia include mutations in the genes HRPT2  and CASR.Patients with bipolar disorder who are receiving long-term lithium treatment are at increased risk for hyperparathyroidism. Elevated calcium levels are found in 15% to 20% of patients who have been taking lithium long-term. However, only a few of these patients have significantly elevated levels of parathyroid hormone and clinical symptoms of hyperparathyroidism. Lithium-associated hyperparathyroidism is usually caused by a single parathyroid adenoma. Secondary
Secondary hyperparathyroidism is due to physiological (i.e. appropriate) secretion of parathyroid hormone (PTH) by the parathyroid glands in response to hypocalcemia (low blood calcium levels). The most common causes are vitamin D deficiency (caused by lack of sunlight, diet or malabsorption) and chronic kidney failure.Lack of vitamin D leads to reduced calcium absorption by the intestine leading to hypocalcemia and increased parathyroid hormone secretion. This increases bone resorption.
An Ottoman army besieged Bitlis for three months in 1531/32, but was forced to retire. Sheref was killed in battle in 1533 and his son and successor submitted to the Ottoman Empire. Mush and Hınıs were removed from the Bitlis emirate, becoming separate sanjaks but still with Ruzaki beys. A Jesuit mission was established in Bitlis in 1685. The Ruzakid Kurdish dynasty in Bitlis lasted until 1849, when an Ottoman governor evicted its last emir, Sheref Bey, who was taken to Constantinople as a prisoner. After this, Bitlis was governed by a Turkish pasha and formed the capital of a vilayet bearing its name. Modern
In 1814 the population of Bitlis town was said to be 12,000 people - one half Muslim, the other half was constituted by Christian Armenians. By 1838 its population was said to be between 15,000 and 18,000 - two thirds Muslim, one third Armenian, and a small minority of Assyrians. In 1898 Lynch considered the population to be close to 30,000, comprising 10,000 Armenians, 300 [As]syrians, and the rest Muslim Kurds (both Alevis and Sunnis included). The Armenians had five schools for boys and three for girls. One third of the population of Bitlis was ethnic Armenian prior to World War I (1914, whereas the majority of the population was Kurdish Muslim (Alevi as well as Sunni Muslims).