Parathyroid tumors can cause increased secretion of parathyroid hormone (PTH) (hyperparathyroidism). Excessive secretion of PTH in the patient’s body increases blood calcium due to osteolysis and increased calcium absorption by the renal tubules and intestines. High blood calcium decreases neuroexcitability, resulting in neuromuscular and psychiatric changes, such as easy fatigue, decreased muscle strength and tone, personality changes, decreased intelligence and memory, emotional instability and insomnia, and occasional psychotic episodes, and in severe cases, coma. Patients with gastrointestinal tract relaxation, may have loss of appetite, nausea, vomiting and constipation, and the incidence of ulcer disease increases. Some patients are accompanied by chronic pancreatitis.