Parathyroid disorders: Difference between revisions
| Line 9: | Line 9: | ||
==Classification== | ==Classification== | ||
Parathyroid disorders may be classified as follows:<ref name="pmid21812031">{{cite journal |vauthors=Bilezikian JP, Khan A, Potts JT, Brandi ML, Clarke BL, Shoback D, Jüppner H, D'Amour P, Fox J, Rejnmark L, Mosekilde L, Rubin MR, Dempster D, Gafni R, Collins MT, Sliney J, Sanders J |title=Hypoparathyroidism in the adult: epidemiology, diagnosis, pathophysiology, target-organ involvement, treatment, and challenges for future research |journal=J. Bone Miner. Res. |volume=26 |issue=10 |pages=2317–37 |year=2011 |pmid=21812031 |pmc=3405491 |doi=10.1002/jbmr.483 |url=}}</ref><ref name="pmid11117980">{{cite journal |vauthors=Marx SJ |title=Hyperparathyroid and hypoparathyroid disorders |journal=N. Engl. J. Med. |volume=343 |issue=25 |pages=1863–75 |year=2000 |pmid=11117980 |doi=10.1056/NEJM200012213432508 |url=}}</ref> | |||
<br><br> | <br><br> | ||
{{Family tree/start}} | {{Family tree/start}} | ||
Revision as of 21:08, 10 October 2017
|
Parathyroid disorders |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Anmol Pitliya, M.B.B.S. M.D.[2], Usama Talib, BSc, MD [3], Seyedmahdi Pahlavani, M.D. [4]
Synonyms and keywords: Disorders of parathyroid gland, parathyroid gland disorders
Overview
The parathyroid glands are small endocrine glands in the neck, usually located behind the thyroid gland, which produce parathyroid hormone. These glands were first discovered in the Indian Rhinoceros by Richard Owen in 1852. The sole function of the parathyroid glands is to maintain the body's calcium level within a very narrow range, so that the nervous and muscular systems can function properly. When blood calcium levels drop below a certain point, calcium-sensing receptors in the parathyroid gland are activated to release hormone into the blood. Parathyroid hormone (PTH, also known as parathormone) is a small protein that takes part in the control of calcium and phosphate homeostasis, as well as bone physiology. Parathyroid hormone has effects antagonistic to those of calcitonin. It increases blood calcium levels by stimulating osteoclasts to break down bone and release calcium. It also increases gastrointestinal calcium absorption by activating vitamin D, and promotes calcium uptake by the kidneys. Hyperparathyroidism is overactivity of the parathyroid glands resulting in excess production of parathyroid hormone (PTH). Overactivity of one or more of the parathyroid glands causes high calcium levels (hypercalcemia) and low levels of phosphorus in the blood. Hyperfunction of the parathyroid glands could be due to adenoma, hyperplasia or, rarely, carcinoma of the parathyroid glands. Hyperparathyroidism may present with symptoms of hypercalcemia, such as painful bones, kidney stones, abdominal pain, psychic moans, and fatigue. An elevated concentration of serum calcium with elevated parathyroid hormone level is diagnostic of primary hyperparathyoidism. Surgical therapy is preferred over medical therapy in primary hyperparathyroidism. Hypoparathyroidism is a disorder characterized by hypocalcemia due to insufficient secretion of PTH. Most common cause for hypoparathyroidism is post-surgical including thyroidectomy, parathyroidectomy, and radical neck dissection. Second most common cause for hypoparathyroidism is autoimmune including polyglandular autoimmune syndrome type 1 and isolated autoimmune hypoparathyroidism. Hypoparathyroidism should be differentiated from other causes of hypocalcemia. Causes of hypocalcemia other than hypoparathyroidism include pseudohypoparathyroidism, hypomagnesemia, hypovitaminosis D, chronic kidney disease, and relative hypocalcemia due to hypoalbuminemia. The hallmark of acute hypocalcemia due to hypoparathyroidism is tetany. A positive history of neck surgery and symptoms of hypocalcemia is suggestive of hypoparathyroidism. The most common symptoms of hypoparathyroidism include tetany, paresthesia, carpopedal spasms, and circumoral numbness. Common symptoms of hypoparathyroidism include abdominal pain, biliary colic, fatigue, muscle cramps, myoclonic jerks, new onset seizure due to hypocalcemia or worsening of seizures, and painful menstruation. Diagnosis of hypoparathyroidism is made by measurement of serum calcium (total and ionized), serum albumin (for correction), phosphate, intact parathyroid hormone (PTH), and 25-hydroxy vitamin D levels. Normal or inappropriately low serum intact parathyroid hormone (PTH) concentration in patients with subnormal serum albumin corrected total or ionized calcium concentration diagnostic of hypoparathyroidism. Pharmacologic medical therapies for hypoparathyroidism include calcium and Vitamin D3 supplementation. Severe hypocalcemia, a potentially life-threatening condition, is treated as soon as possible with intravenous calcium (e.g. as calcium gluconate).
Classification
Parathyroid disorders may be classified as follows:[1][2]
| Parathyroid disorders | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Hyperparathyroidism | Familial hypocalciuric hypercalcemia | Hypoparathyroidism | Parathyroid hormone resistance diseases | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Primary | Secondary | Tertiary | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Post-surgical | Autoimmune | Genetic defects associated | Functional | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Pseudohypoparathyroidism | Acrodysostosis | Blomstrand chondrodysplasia | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Pseudohypoparathyroidism type 1 | Pseudohypoparathyroidism type 2 | Acrodysostosis type 1 | Acrodysostosis type 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Type 1A | Type 1B | Type 1C | Pseudopseudohypoparathyroidism | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Diagnosis
| Disorder | Laboratory findings | ||||
|---|---|---|---|---|---|
| Parathyroid hormone | Serum calcium | Serum phosphate | Other findings | ||
| Hyperparathyroidism | Primary hyperparathyroidism | ↑ | ↑ | ↓/Normal |
|
| Secondary hyperparathyroidism | ↑ | ↓/Normal | ↑ | -- | |
| Tertiary hyperparathyroidism | ↑ | ↑ | ↑ | -- | |
| Familial hypocalciuric hypercalcemia | Normal/↑ | Normal/↑ | -- |
| |
| Hypoparathyroidism | ↓ | ↓ | ↑ |
| |
| Pseudohypoparathyroidism | Type 1A | ↑ | ↓ | ↑ | |
| Type 1B | ↑ | ↓ | ↑ | ||
| Type 1C | ↑ | ↓ | ↑ | ||
| Pseudopseudohypoparathyroidism | Normal | Normal | Normal | -- | |
| Type 2 | ↑ | ↓ | ↑ |
| |
| Acrodysostosis | Acrodysostosis type 1 | ↑ | ↓ | ↑ |
|
| Acrodysostosis type 2 | ↑ | ↓ | ↑ |
| |
| Blomstrand chondrodysplasia | ↑ | ↓ | ↑ | ||
Differentiating Parathyroid Disorders
- The main presenting features of parathyroid disorders are related to calcium secretion. Accordingly, differentiating parathyroid disorders from other diseases is mainly dependent to changes in calcium level. Following algorithms are designed to differentiate diseases according to hypercalcemia and hypocalcemia.
Hypercalcemia
Hypocalcemia
| Hypocalcemia | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Repeat (check ionized calcium or calcium corrected for albumin) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Hypocalcemia confirmed | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Look for reversible cause | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Reversible cause present | Reversible cause absent | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| History of drug use | Serum magnesium levels | Blood transfusion | Measure intact parathyroid hormone (PTH) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Drug induced hypocalcemia (bisphosphonates, cisplatin, antiepileptics, aminoglycosides, proton pump inhibitors) | Hypomagnesemia (sometimes hypermagnesemia) | Calcium levels reaches normal after transfusion is stopped | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ↓ PTH | ↑ PTH | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Hypoparathyroidism | History of chronic kidney disease | ↓ 25-hydroxy vitamin D | Genetic testing | Inflammatory conditions | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| History of anterior neck surgery | Associated with autoimmunity | Family history present | None of these present | Secondary hyperparathyroidism (may have ↓/normal calcium) | Hypovitaminosis D | PTH resistance disorders | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Post-surgical hypoparathyroidism | Autoimmune polyendocrinopathy syndrome or Isolated autoimmune hypoparathyroidism | Hypoparathyroidism related to other genetic causes | Other causes of hypoparathyroidism should bbe evaluted (for other causes of hypoparathyroidims, click here) | Sepsis | Acute pancreatitis | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
- ↑ Bilezikian JP, Khan A, Potts JT, Brandi ML, Clarke BL, Shoback D, Jüppner H, D'Amour P, Fox J, Rejnmark L, Mosekilde L, Rubin MR, Dempster D, Gafni R, Collins MT, Sliney J, Sanders J (2011). "Hypoparathyroidism in the adult: epidemiology, diagnosis, pathophysiology, target-organ involvement, treatment, and challenges for future research". J. Bone Miner. Res. 26 (10): 2317–37. doi:10.1002/jbmr.483. PMC 3405491. PMID 21812031.
- ↑ Marx SJ (2000). "Hyperparathyroid and hypoparathyroid disorders". N. Engl. J. Med. 343 (25): 1863–75. doi:10.1056/NEJM200012213432508. PMID 11117980.