The hyperparathyroidism is an excess of parathyroid hormone in the bloodstream due to the over activity of one or more of the body’s 4 parathyroid glands. It is known that these glands are about a size of grain rice and they are located in the neck. It is known that the parathyroid glands are producing parathyroid hormone which can help to maintain an appropriate balance of calcium in the bloodstream and in tissues which depend on calcium for the proper functioning.
There are two types of this disease. In the primary hyperparathyroidism, there is an enlargement of one or more of the parathyroid glands which is causing overproduction of the hormone. This is resulting in high levels of calcium in the blood, a condition which is known as hypercalemia, which is causing many different health problems. The most common treatment for the primary hyperparathyroidism is the surgery.
It is known that the secondary hyperparathyroidism happens as a result of another disease which initially causes low levels of calcium in the body over time and the increased parathyroid hormone levels happen. The most common complications caused are kidney stones; osteoporosis; neonatal hypoparathyroidism and cardiovascular disease.
The hyperparathyroidism is often diagnosed before signs and symptoms of this disorder are apparent. When the symptoms of the hyperparathyroidism happen, then they are result of the damage or dysfunction in other organs or tissues due to the high calcium levels which are circulating in the blood and urine or for having too little calcium in your bones. The symptoms of the hyperparathyroidism can be so mild and nonspecific so they do not seem at all related to parathyroid function or they can become so severe. Here are different signs and symptoms which can happen with the hyperparathyroidism :
- Nausea, vomiting or loss of appetite
- Frequent complications of illness with no apparent cause
- Bone and joint pain
- Depression or forgetfulness
- Tiring easily or weakness
- Abdominal pain
- Excessive urination
- Kidney stones
- Fragile bones that easily fracture (osteoporosis)
The primary hyperparathyroidism happens due to some problems with one or more of the parathyroid glands, such as
- A cancerous (malignant) tumor is a rare cause of the primary hyperparathyroidism 
- An enlargement (hyperplasia) of two or more parathyroid glands accounts for most other cases 
- A noncancerous growth (adenoma) on a gland is the most common cause 
The primary hyperparathyroidism usually happens randomly, but also there are some cases when people inherit a gene which causes the disorder.
The secondary hyperparathyroidism is the result of another condition which lowers the calcium levels. This is a reason why the parathyroid glands overwork to compensate the loss of calcium. Here are some factors which can lead to secondary hyperparathyroidism:
- Chronic kidney failure: We know that kidneys convert the Vitamin D into a form which the body can use. If the kidneys function poorly, then the usable Vitamin D can decline and the calcium levels drop. The most common cause is the kidney failure. 
- Severe calcium deficiency: The body may not get enough calcium from the diet and often the digestive system does not absorb the calcium from it. 
- Severe Vitamin D deficiency: The Vitamin D can help to maintain appropriate levels of calcium in the blood and it can help the digestive system to absorb calcium from the body. The body produces Vitamin D when the skin is exposed to sunlight and you can consume some Vitamin D in food. If you do not get enough Vitamin D, then the calcium levels can drop. 
Hyperparathyroidism Risk factors
There are different factors which can increase your risk of getting this, such as
- Have taken lithium, a drug most often use to treat bipolar disorder
- You have had radiation treatment for cancer that has exposed your neck to radiation 
- You are having a rare, inherited disorder, such as multiple endocrine neoplasia, type 1, which usually affects multiple glands
- You have had prolonged, severe calcium or Vitamin D deficiency [6,7]
- Are a woman who has gone through menopause
 Madkhali T, Alhefdhi A, Chen H, Elfenbein D. Primary hyperparathyroidism. Ulusal Cerrahi Dergisi/Turkish Journal of Surgery. 2016;32(1):58–66. doi:10.5152/UCD.2015.3032
 Goswami S, Ghosh S. Hyperparathyroidism: Cancer and mortality. Indian Journal of Endocrinology and Metabolism. 2012;16(Suppl2):S217–S220. doi:10.4103/2230-8210.104042
 Albright F, Bloomberg E, Castleman B, et al. Hyperparathyroidism due to diffuse hyperplasia of all parathyroid glands rather than adenoma of one: Clinical studies on three such cases. Archives of Internal Medicine. 1934;54(3):315-29. doi:10.1001/archinte.1934.00160150002001
 Al-Hassan MS, Mekhaimar M, El Ansari W, et al. Giant parathyroid adenoma: A case report and review of the literature. Journal of Medical Case Reports. 2019;13.
 Cannata-Andia JB, Carrera F. The pathophysiology of secondary hyperparathyroidism and the consequences of uncontrolled mineral metabolism in chronic kidney disease: The role of COSMOS. NDT Plus. 2008;1(Suppl1):i2–i6. doi:10.1093/ndtplus/sfm037
 Paik JM, Taylor EN. Calcium intake and risk of primary hyperparathyroidism in women: prospective cohort study. BMJ. 2012;345:e6390.
 American Family Physician. Vitamin D insufficiency as a cause of hyperparathyroidism. 2005;71(1):46-9.
 Woll ML, Mazeh H, Anderson BM, et al. Breast radiation correlates with side of parathyroid adenoma. World Journal of Surgery. 2012;36(3):607-11. doi:10.1007/s00268-011-1394-y.