Hyperparathyroidism | |
---|---|
Thyroid and parathyroid | |
Specialty | Endocrinology |
Symptoms | None, kidney stones, weakness, depression, bone pains, confusion, increased urination [1] [2] [3] |
Complications | Osteoporosis [2] [3] |
Usual onset | 50 to 60 [2] |
Types | Primary, secondary |
Causes | Primary: parathyroid adenoma, multiple benign tumors, parathyroid cancer [1] [2] Secondary: vitamin D deficiency, chronic kidney disease, low blood calcium [1] |
Diagnostic method | High blood calcium and high PTH levels [2] |
Treatment | Monitoring, surgery, intravenous normal saline, cinacalcet [1] [2] |
Frequency | ~2 per 1,000 [3] |
Hyperparathyroidism is an increase in parathyroid hormone (PTH) levels in the blood. [1] [4] This occurs from a disorder either within the parathyroid glands (primary hyperparathyroidism) or as response to external stimuli (secondary hyperparathyroidism). [1] Symptoms of hyperparathyroidism are caused by inappropriately normal or elevated blood calcium excreted from the bones and flowing into the blood stream in response to increased production of parathyroid hormone. [1] In healthy people, when blood calcium levels are high, parathyroid hormone levels should be low. With long-standing hyperparathyroidism, the most common symptom is kidney stones. [1] Other symptoms may include bone pain, weakness, depression, confusion, and increased urination. [1] [2] Both primary and secondary may result in osteoporosis (weakening of the bones). [2] [3]
In 80% of cases, primary hyperparathyroidism is due to a single benign tumor known as a parathyroid adenoma. [1] [2] Most of the remainder are due to several of these adenomas. [1] [2] Very rarely it may be due to parathyroid cancer. [2] Secondary hyperparathyroidism typically occurs due to vitamin D deficiency, chronic kidney disease, or other causes of low blood calcium. [1] The diagnosis of primary hyperparathyroidism is made by finding elevated calcium and PTH in the blood. [2]
Primary hyperparathyroidism may only be cured by removing the adenoma or overactive parathyroid glands. [5] [1] [2] In asymptomatic patients who present with mildly elevated blood calcium levels, with otherwise normal kidneys, and with normal bone density, monitoring may be all that is required. [2] The medication cinacalcet may also be used to decrease PTH levels in those unable to have surgery although it is not a cure. [2] In patients with very high blood calcium levels, treatment may include large amounts of intravenous normal saline. [1] Low vitamin D should be corrected in those with secondary hyperparathyroidism but low Vitamin D pre-surgery is controversial for those with primary hyperparathyroidism. [6] Low vitamin D levels should be corrected post-parathyroidectomy. [2]
In primary hyperparathyroidism, about 75% of people are "asymptomatic". [1] While most primary patients are asymptomatic at the time of diagnosis, 'asymptomatic' is poorly defined and represents only those without "obvious clinical sequelae" such as kidney stones, bone disease, or hypercalcemic crisis. [5] These "asymptomatic" patients may have other symptoms such as depression, anxiety, gastrointestinal distress, and neuromuscular problems that are not counted as symptoms. [5] The problem is often picked up incidentally during blood work for other reasons, and the test results show a higher amount of calcium in the blood than normal. [3] Many people only have non-specific symptoms. [7]
Common manifestations of hypercalcemia include constipation, vomiting, weakness, lethargy, fatigue, depression, bone pain, muscle soreness (myalgias), joint pain, decreased appetite, feelings of nausea, abdominal pain, pancreatitis, polyuria, polydipsia, cognitive impairment, kidney stones ( [nb 1] ), vertigo and osteopenia or osteoporosis. [10] [11] A history of acquired racquet nails (brachyonychia) may be indicative of bone resorption. [12] Radiographically, hyperparathyroidism has a pathognomic finding of rugger jersey spine. [13] Parathyroid adenomas are very rarely detectable on clinical examination. Surgical removal of a parathyroid tumor eliminates the symptoms in most patients.[ citation needed ]
In secondary hyperparathyroidism due to lack of vitamin D absorption, the parathyroid gland is behaving normally; clinical problems are due to bone resorption and manifest as bone syndromes such as rickets, osteomalacia, and renal osteodystrophy. [14]
Causes of primary hyperparathyroidism include parathyroid adenoma (80% of patients), multiglandular disease usually seen as hyperplasia of the 4 parathyroid glands (15-20% of patients), parathyroid carcinoma (less than 1% of patients). [15] Primary hyperparathyroidism occurs sporadically and most patients do not have a family history. [15] Radiation exposure increases the risk of primary hyperparathyroidism. [1] Additional risk factors include lithium [16] and thiazide diuretics [17] exposure. A number of genetic conditions including multiple endocrine neoplasia syndromes, hyperparathyroidism-jaw tumor syndrome, [18] familial hypocalciuric hypercalcemia, [19] neonatal severe hyperparathyroidism also increase the risk. [1] Parathyroid adenomas have been linked with DDT although a causal link has not yet been established. [20] The most common causes for secondary hyperparathyroidism include vitamin D deficiency, chronic kidney disease, inadequate calcium intake, malabsorption. [21] Tertiary hyperparathyroidism most commonly occurs from prolonged secondary hyperparathyroidism. [22]
The parathyroid is composed of 4 glands with 2 located superiorly and 2 located inferiorly. [23] The parathyroid glands are located on the posterior thyroid and are derived from the endoderm of the 3rd and 4th pharyngeal pouches. [23] Specifically, the inferior parathyroid glands are derived from the 3rd pharyngeal pouch and the superior parathyroid glands are derived from the 4th pharyngeal pouch dorsal wing. [24] The ultimopharyngeal body is derived from the 4th pharyngeal pouch ventral wing and the parafollicular cells ( C-cells) are derived when the ultimopharyngeal bodies fuse with the posterolateral thyroid. [24] The parathyroid glands separates from the pharyngeal wall and attaches to the posterior thyroid during the 7th week of human embryonic development. [23]
Normal parathyroid glands measure the ionized calcium (Ca2+) concentration in the blood and secrete parathyroid hormone accordingly; if the ionized calcium rises above normal, the secretion of PTH is decreased, whereas when the Ca2+ level falls, parathyroid hormone secretion is increased. [8]
Rapid PTH regulation is controlled by the parathyroid G-protein coupled, calcium sensing receptors which responds to fluctuations in serum calcium levels. [25] Alternatively, prolonged changes in serum calcium influences mRNA-binding proteins altering the encoding of PTH mRNA. [26] There are also calcium independent mechanisms which include repression of PTH transcription through 1α,25-dihydroxyvitamin D binding with the vitamin D receptor. [26] Furthermore, 1α,25-dihydroxyvitamin D also has an impact on the expression of calcium-sensing receptors, indirectly affecting PTH secretion. [26]
Effects of PTH on the Bones
PTH stimulates the bones to release calcium through multiple mechanisms. 1) PTH stimulates osteoblasts which increase expression of RANKL which causes differentiation of the osteoblasts into osteocytes. [27] 2) PTH inhibits secretion of osteoprotegerina to allow for osteoclast differentiation. [27] 3) PTH will also directly activate osteoclasts to cause bone resorption through degradation of hydroxyapatite and organic material. [27] This then causes bone to release calcium into the blood.
Effects of PTH on the Kidneys
Calcium reabsorption in the nephron occurs in proximal convoluted tubule and at the ascending Loop of Henle. [28] PTH acts on the distal convoluted tubule and collecting duct to increase calcium reabsorption in the nephron. [28] PTH also acts on the proximal convoluted tubule to decrease phosphate reabsorption to lower the serum phosphate. [28] This decreases formation of insoluble calcium phosphate salts leading to an increase in serum ionized calcium.
Effects of PTH on the Small Intestines
PTH stimulates the production of 1-alpha-hydroxylase in the proximal convoluted tubule. [28] This enzyme activation hydroxylates inactive 25-hydroxycholecalciferol to active vitamin D (1, 25 dihydroxycholecalciferol). [28] Active vitamin D allows for calcium absorption through transcellular and paracellular pathways. [28]
Secondary hyperparathyroidism occurs if the calcium level is abnormally low. The normal glands respond by secreting parathyroid hormone at a persistently high rate. This typically occurs when the 1,25 dihydroxyvitamin D3 levels in the blood are low and hypocalcemia is present. A lack of 1,25 dihydroxyvitamin D3 can result from a deficient dietary intake of vitamin D, or from a lack of exposure of the skin to sunlight, so the body cannot make its own vitamin D from cholesterol. [29] The resulting hypovitaminosis D is usually due to a partial combination of both factors. Vitamin D3 (or cholecalciferol) is converted to 25-hydroxyvitamin D (or calcidiol) by the liver, from where it is transported via the circulation to the kidneys, and it is converted into the active hormone, 1,25 dihydroxyvitamin D3. [8] [29] Thus, a third cause of secondary hyperparathyroidism is chronic kidney disease. Here the ability to manufacture 1,25 dihydroxyvitamin D3 is compromised, resulting in hypocalcemia.[ citation needed ]
The gold standard of diagnosis is the PTH immunoassay. Once an elevated PTH has been confirmed, the goal of diagnosis is to determine the type of hyperparathyroidism (primary, secondary, or tertiary hyperparathyroidism) by obtaining a serum calcium, phosphate, and PTH levels.
Serum calcium | Phosphate | Vitamin D Level | PTH | Likely type |
---|---|---|---|---|
↑ | ↓ | ↑ | ↑/↔ | Primary hyperparathyroidism [30] |
↓/↔ | ↑ | ↓ | ↑ | Secondary hyperparathyroidism [30] |
↑ | ↑ | ↓ | ↑ | Tertiary hyperparathyroidism [31] |
Primary hyperparathyroidism has high calcium, vitamin D, and PTH levels and a low phosphate level. [30] [31] Secondary hyperparathyroidism has low serum calcium and vitamin D levels, and high phosphate and PTH levels. [30] [31] Tertiary hyperparathyroidism has high serum calcium, phosphate, and PTH and low vitamin D levels. [30] [31] Tertiary hyperparathyroidism is differentiated from primary hyperparathyroidism by a history of chronic kidney failure and secondary hyperparathyroidism.[ citation needed ]
Hyperparathyroidism can cause hyperchloremia and increase renal bicarbonate loss, which may result in a normal anion gap metabolic acidosis. [32] ALP level can be elevated due to bone turnover. Additionally further tests can be completed to rule out other causes and complications of hyperparathyroidism including a 24-hour urinary calcium for familial hypocalciuric hypercalcemia, DEXA scan to evaluate for osteoporosis, osteopenia, or fragility fractures, and genetic testing. [33] [34] [35] [36] Additionally a CT scan without contrast or renal ultrasound can be done to assess for nephrolithiasis and/or nephrocalcinosis if there is concern for it. [36]
Differential diagnoses of hypercalcemia include humoral hypercalcemia of malignancy, renal failure, malignant bone destruction (such as multiple myeloma, metastatic breast cancer, lymphoma), thiazide diuretics, lithium, immobilization, hyperthyroidism, milk alkali syndrome, multiple endocrine adenomatosis syndromes, and granulomatous diseases. [37] Additionally, familial benign hypocalciuric hypercalcamia can present with similar lab changes. [1] In this condition, the calcium creatinine clearance ratio, however, is typically under 0.01 due to the low levels urine calcium. [1]
In primary hyperparathyroidism, parathyroid hormone (PTH) levels are either elevated or "inappropriately normal" in the presence of elevated calcium. Typically, PTH levels vary greatly over time in the affected patient and (as with Ca and Ca++ levels) must be retested several times to see the pattern. The currently accepted test for PTH is intact PTH, which detects only relatively intact and biologically active PTH molecules. Older tests often detected other, inactive fragments. Even intact PTH may be inaccurate in patients with kidney dysfunction.[ citation needed ] Intact PTH blood tests may be falsely low if biotin has been ingested in the previous few days prior to the blood test. [38]
In cases of primary hyperparathyroidism or tertiary hyperparathyroidism, heightened PTH leads to increased serum calcium (hypercalcemia) due to:[ citation needed ]
In primary hyperparathyroidism, serum phosphate levels are abnormally low as a result of decreased reabsorption of phosphate in the kidney tubules. However, this is only present in about 50% of cases. This contrasts with secondary hyperparathyroidism and tertiary hyperparathyroidism, in which serum phosphate levels are generally elevated because of kidney disease.[ citation needed ]
Alkaline phosphatase levels are usually high in hyperparathyroidism due to high bone turn over. In primary hyperparathyroidism, levels may remain within the normal range, but this is inappropriately normal given the increased levels of plasma calcium.[ citation needed ]
Nuclear medicine imaging methods are used by surgeons to locate which parathyroid gland is responsible for hyperparathyroidism or to find ectopic parathyroid adenomas, most commonly found in the anterior mediastinum.[ citation needed ] Historically, technetium sestamibi scintigraphy was the main method used or this indication. [39] Recently 18F-fluorocholine PET/CT tend to be more and more performed due to excellent diagnostic performance. [40] [41]
Primary hyperparathyroidism results from a hyperfunction of the parathyroid glands themselves. 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. [42] [43]
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 pheochromocytoma. Other mutations that have been linked to parathyroid neoplasia include mutations in the genes HRPT2 and CASR. [44] [45]
Patients with bipolar disorder who are receiving long-term lithium treatment are at increased risk for hyperparathyroidism. [46] 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. [46]
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 [47] (caused by lack of sunlight, diet or malabsorption) and chronic kidney failure.[ citation needed ] Vitamin D deficiency can result from malabsorption or decreased vitamin D intake such as with gastric bypass, small bowel disease, pancreatic disease, and dietary causes. [48] Other causes include decreased skin synthesis of vitamin D such as decreased exposure to sunlight and skin disorders. Insufficient vitamin D synthesis such as defective 25-hydroxylation, 1-alpha hydroxylase, and 1-alpha 25-hydroxylation can also contribute to vitamin D deficiency.
Lack of vitamin D leads to reduced calcium absorption by the intestine leading to hypocalcemia and increased parathyroid hormone secretion. This increases bone resorption. In chronic kidney failure the problem is more specifically failure to convert vitamin D to its active form in the kidney. The bone disease in secondary hyperparathyroidism caused by kidney failure is termed renal osteodystrophy. [49]
Tertiary hyperparathyroidism is seen in those with long-term secondary hyperparathyroidism, which eventually leads to hyperplasia of the parathyroid glands and a loss of response to serum calcium levels. This disorder is most often seen in patients with end-stage kidney disease and is an autonomous activity. [50] Patients with late-stage kidney disease have an increased likelihood of developing tertiary hyperparathyroidism if not promptly corrected. [51] In patients with late-stage kidney disease phosphate levels are elevated which directly affects the parathyroid glands and increases PTH production. Additionally, studies have shown that even in the absence of secondary hyperparathyroidism, those with X-Linked hypophosphatemia rickets who are on phosphate treatment are more susceptible to developing tertiary hyperparathyroidism. [52]
Treatment depends on the type of hyperparathyroidism encountered.
Parathyroidectomy is a curative therapy for symptomatic hyperparathyroidism. Additionally, it decrease the risk of nephrolithiasis, osteoporosis, fragility fractures, and improves bone mineral density. Studies have also found that parathyroidectomy for hyperparathyroidism improves fatigue, weakness, depression, and memory. While parathyroidectomy is recommended for all patients with hyperparathyroidism who are symptomatic, indications of surgery for those who are asymptomatic include the following: [53]
A 2020 Cochrane systematic review compared the surgical procedures of minimally invasive parathyroidectomy and classically used bilateral neck exploration, however it did not find one approach to be superior to the other in either benefits or risks. [54]
Surgery can rarely result in hypoparathyroidism.[ citation needed ]
In patients with secondary hyperparathyroidism, the high PTH levels are an appropriate response to low calcium and treatment must be directed at the underlying cause of this (usually vitamin D deficiency or chronic kidney failure). If this is successful, PTH levels return to normal levels, unless PTH secretion has become autonomous (tertiary hyperparathyroidism). [50] Hyperphosphatemia may be treated by decreasing dietary intake of phosphate. If phosphate remains persistently elevated above 5.5 mg/dL with dietary restriction, then phosphate binders may be used. [55] Vitamin D deficiency may be treated with vitamin D supplementation. However in patients with CKD, patients should not receive vitamin D supplementation if they are elevated serum phosphate levels or have hypercalcemia. [56]
Parathyroidectomy is indicated in tertiary hyperparathyroidism for patients who have severe osteopenia, severe persistent hypercalcemia (>11.0 mg/ dL), calciphylaxis, bone pain, or pathological fracture. [57] A systematic review found surgical treatment to be superior regarding cure rates than medical therapy with cinacalcet with lower risk of complications. [58]
A calcimimetic (such as cinacalcet) is a potential therapy for some people with severe hypercalcemia and primary hyperparathyroidism who are unable to undergo parathyroidectomy, and for secondary hyperparathyroidism on dialysis. [59] [60] Treatment of secondary hyperparathyroidism with a calcimimetic in those on dialysis for CKD does not alter the risk of early death; however, it does decrease the likelihood of needing a parathyroidectomy. [61] Treatment carries the risk of low blood calcium levels and vomiting. [61]
In the developed world, between one and four per thousand people are affected. [3] Primary hyperparathyroidism is the most common type. [1] Certain exposures increase the risk of developing primary hyperparathyroidism such as sex and age. It occurs three times more often in women than men and is often diagnosed between the ages of 50 and 60 but is not uncommon before then. [2] The disease was first described in the 1700s. [32] In the late 1800s, it was determined to be related to the parathyroid. [32] Surgery as a treatment was first carried out in 1925. [32] The United States prevalence of primary hyperparathyroidism from 2010 was 233 per 100,000 women and 85 per 100,000 men. Black and white women aged 70–79 have the highest overall prevalence. [62] Secondary hyperparathyroidism is most commonly caused by chronic kidney disease and vitamin D deficiency. [63] The prevalence of vitamin D deficiency is about 50% of the world population and chronic kidney disease prevalence is 15% of the United States population. [51]
The oldest known case was found in a cadaver from an Early Neolithic cemetery in southwest Germany. [64]
Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods. Humans usually have four parathyroid glands, located on the back of the thyroid gland in variable locations. The parathyroid gland produces and secretes parathyroid hormone in response to low blood calcium, which plays a key role in regulating the amount of calcium in the blood and within the bones.
Parathyroid hormone (PTH), also called parathormone or parathyrin, is a peptide hormone secreted by the parathyroid glands that regulates the serum calcium concentration through its effects on bone, kidney, and intestine.
Calcium metabolism is the movement and regulation of calcium ions (Ca2+) in (via the gut) and out (via the gut and kidneys) of the body, and between body compartments: the blood plasma, the extracellular and intracellular fluids, and bone. Bone acts as a calcium storage center for deposits and withdrawals as needed by the blood via continual bone remodeling.
Hypercalcemia, also spelled hypercalcaemia, is a high calcium (Ca2+) level in the blood serum. The normal range is 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L), with levels greater than 2.6 mmol/L defined as hypercalcemia. Those with a mild increase that has developed slowly typically have no symptoms. In those with greater levels or rapid onset, symptoms may include abdominal pain, bone pain, confusion, depression, weakness, kidney stones or an abnormal heart rhythm including cardiac arrest.
Disorders of calcium metabolism occur when the body has too little or too much calcium. The serum level of calcium is closely regulated within a fairly limited range in the human body. In a healthy physiology, extracellular calcium levels are maintained within a tight range through the actions of parathyroid hormone, vitamin D and the calcium sensing receptor. Disorders in calcium metabolism can lead to hypocalcemia, decreased plasma levels of calcium or hypercalcemia, elevated plasma calcium levels.
Parathyroid chief cells are one of the two cell types of the parathyroid glands, along with oxyphil cells. The chief cells are much more prevalent in the parathyroid gland than the oxyphil cells. It is perceived that oxyphil cells may be derived from chief cells at puberty, as they are not present at birth like chief cells.
Hypoparathyroidism is decreased function of the parathyroid glands with underproduction of parathyroid hormone (PTH). This can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany, and several other symptoms. It is a very rare disease. The condition can be inherited, but it is also encountered after thyroid or parathyroid gland surgery, and it can be caused by immune system-related damage as well as a number of rarer causes. The diagnosis is made with blood tests, and other investigations such as genetic testing depending on the results. The primary treatment of hypoparathyroidism is calcium and vitamin D supplementation. Calcium replacement or vitamin D can ameliorate the symptoms but can increase the risk of kidney stones and chronic kidney disease. Additionally, medications such as recombinant human parathyroid hormone or teriparatide may be given by injection to replace the missing hormone.
Parathyroidectomy is the surgical removal of one or more of the (usually) four parathyroid glands. This procedure is used to remove an adenoma or hyperplasia of these glands when they are producing excessive parathyroid hormone (PTH): hyperparathyroidism. The glands are usually four in number and located adjacent to the posterior surface of the thyroid gland, but their exact location is variable. When an elevated PTH level is found, a sestamibi scan or an ultrasound may be performed in order to confirm the presence and location of abnormal parathyroid tissue.
Cinacalcet, sold under the brand name Sensipar among others, is a medication used to treat primary hyperparathyroidism, tertiary hyperparathyroidism and parathyroid carcinoma. Cinacalcet acts as a calcimimetic by allosteric activation of the calcium-sensing receptor that is expressed in various human organ tissues.
Renal osteodystrophy is currently defined as an alteration of bone morphology in patients with chronic kidney disease (CKD). It is one measure of the skeletal component of the systemic disorder of chronic kidney disease-mineral and bone disorder (CKD-MBD). The term "renal osteodystrophy" was coined in 1943, 60 years after an association was identified between bone disease and kidney failure.
Primary hyperparathyroidism is a medical condition where the parathyroid gland produce excess amounts of parathyroid hormone (PTH). The symptoms of the condition relate to the resulting elevated serum calcium (hypercalcemia), which can cause digestive symptoms, kidney stones, psychiatric abnormalities, and bone disease.
Osteitis fibrosa cystica is a skeletal disorder resulting in a loss of bone mass, a weakening of the bones as their calcified supporting structures are replaced with fibrous tissue, and the formation of cyst-like brown tumors in and around the bone. Osteitis fibrosis cystica (OFC), also known as osteitis fibrosa, osteodystrophia fibrosa, and von Recklinghausen's disease of bone, is caused by hyperparathyroidism, which is a surplus of parathyroid hormone from over-active parathyroid glands. This surplus stimulates the activity of osteoclasts, cells that break down bone, in a process known as osteoclastic bone resorption. The hyperparathyroidism can be triggered by a parathyroid adenoma, hereditary factors, parathyroid carcinoma, or renal osteodystrophy. Osteoclastic bone resorption releases minerals, including calcium, from the bone into the bloodstream, causing both elevated blood calcium levels, and the structural changes which weaken the bone. The symptoms of the disease are the consequences of both the general softening of the bones and the excess calcium in the blood, and include bone fractures, kidney stones, nausea, moth-eaten appearance in the bones, appetite loss, and weight loss.
Secondary hyperparathyroidism is the medical condition of excessive secretion of parathyroid hormone (PTH) by the parathyroid glands in response to hypocalcemia, with resultant hyperplasia of these glands. This disorder is primarily seen in patients with chronic kidney failure. It is sometimes abbreviated "SHPT" in medical literature.
Tertiary hyperparathyroidism is a condition involving the overproduction of the hormone, parathyroid hormone, produced by the parathyroid glands. The parathyroid glands are involved in monitoring and regulating blood calcium levels and respond by either producing or ceasing to produce parathyroid hormone.
A parathyroid adenoma is a benign tumor of the parathyroid gland. It generally causes hyperparathyroidism; there are very few reports of parathyroid adenomas that were not associated with hyperparathyroidism.
Parathyroid carcinoma is a rare cancer resulting in parathyroid adenoma to carcinoma progression. It forms in tissues of one or more of the parathyroid glands.
An endocrine bone disease is a bone disease associated with a disorder of the endocrine system. An example is osteitis fibrosa cystica.
Many conditions are associated with disorders of the function of the parathyroid gland. Some disorders may be purely anatomical resulting in an enlarged gland which will raise concern. Such benign disorders, such as parathyroid cyst, are not discussed here. Parathyroid diseases can be divided into those causing hyperparathyroidism, and those causing hypoparathyroidism.
Familial hypocalciuric hypercalcemia (FHH) is an inherited condition that can cause hypercalcemia, a serum calcium level typically above 10.2 mg/dL; although uncommon. It is also known as familial benign hypocalciuric hypercalcemia (FBHH) where there is usually a family history of hypercalcemia which is mild, a urine calcium to creatinine ratio <0.01, and urine calcium <200 mg/day.
A calcimimetic is a pharmaceutical drug that mimics the action of calcium on tissues, by allosteric activation of the calcium-sensing receptor that is expressed in various human organ tissues. Calcimimetics are used to treat secondary hyperparathyroidism (SHPT).
his constellation of symptoms has led to the mnemonic "Stones, bones, abdominal moans, and psychic groans," which is used to recall the signs and symptoms of hypercalcemia, particularly as a result of primary hyperparathyroidism.
"Stones" refers to kidney stones, "bones" to associated destructive bone changes, "groans" to the pain of stomach and peptic ulcers that occur in some cases, and "moans" to the depression that frequently accompanies the disease and is often its first and most prominent manifestation.