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| {{Infobox medical condition (new) | | {{Short description|Endocrine disorder characterized by low levels of parathyroid hormone}} |
| | name = Hypoparathyroidism
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| [[File:Postoperative Hypoparathyroidism in Thyroid Surgery Fig4.jpg|thumb|Postoperative Hypoparathyroidism in Thyroid Surgery]]
| | ==Hypoparathyroidism== |
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| '''Hypoparathyroidism''' is decreased function of the [[parathyroid gland]]s with underproduction of [[parathyroid hormone]]. This can lead to [[hypocalcemia|low levels of calcium in the blood]], often causing [[cramp]]ing and twitching of muscles or [[Tetany (medical sign)|tetany]] (involuntary muscle contraction), and several other symptoms. The condition can be inherited, but it is also encountered after [[thyroidectomy|thyroid]] or [[parathyroidectomy|parathyroid gland surgery]], and it can be caused by [[autoimmunity|immune system-related damage]] as well as a number of rarer causes. The diagnosis is made with [[blood test]]s, and other investigations such as [[genetic testing]] depending on the results. The treatment of hypoparathyroidism is limited by the fact that there is no exact form of the hormone that can be administered as [[hormone therapy|replacement]]. However teriparatide, brand name [[Forteo]], a biosimilar peptide to parathyroid hormone, may be given by injection. Calcium replacement or [[vitamin D]] can ameliorate the symptoms but can increase the risk of [[kidney stone]]s and [[chronic kidney disease]].<ref name=Bilezikian/> | | '''Hypoparathyroidism''' is an endocrine disorder characterized by insufficient production of [[parathyroid hormone]] (PTH) by the [[parathyroid glands]]. This condition leads to low levels of calcium in the blood, a condition known as [[hypocalcemia]], and can result in a variety of symptoms and complications. |
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| | ==Causes== |
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| | Hypoparathyroidism can be caused by several factors, including: |
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| ==Signs and symptoms==
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| The main symptoms of hypoparathyroidism are the result of the [[hypocalcemia|low blood calcium level]], which interferes with normal [[muscle contraction]] and [[action potential|nerve conduction]]. As a result, people with hypoparathyroidism can experience [[paresthesia]], an unpleasant tingling sensation around the mouth and in the hands and feet, as well as muscle cramps and severe spasms known as "[[tetany]]" that affect the hands and feet.<ref name=Shoback>{{cite journal |author=Shoback D |title=Hypoparathyroidism |journal=N. Engl. J. Med. |volume=359 |issue=4 |pages=391–403 |date=July 2008 |pmid=18650515 |doi=10.1056/NEJMcp0803050}}</ref> Many also report a number of subjective symptoms such as [[fatigue (medical)|fatigue]], [[headache]]s, [[bone pain]] and [[insomnia]].<ref name=Bilezikian>{{cite journal |vauthors=Bilezikian JP, Khan A, Potts JT, etal |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 |date=October 2011 |pmid=21812031 |doi=10.1002/jbmr.483 |pmc=3405491}}</ref> Crampy [[abdominal pain]] may occur.<ref name=Potts>{{cite book |author=Potts Jr JT |veditors=Kasper DL, Braunwald E, Fauci AS |title=Harrison's Principles of Internal Medicine|edition=16th |year=2005 |publisher=McGraw-Hill |location=New York, NY |isbn=978-0-07-139140-5 |pages=2249–68 |chapter=Diseases of the parathyroid gland|display-editors=etal}}</ref> [[Physical examination]] of someone with [[hypocalcemia]] may show tetany, but it is also possible to provoke tetany of the facial muscles by tapping on the [[facial nerve]] (a phenomenon known as [[Chvostek's sign]]) or by using the cuff of a [[sphygmomanometer]] to temporarily obstruct the blood flow to the arm (a phenomenon known as [[Trousseau sign of latent tetany|Trousseau's sign of latent tetany]]).<ref name=Potts/>
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| A number of [[medical emergency|medical emergencies]] can arise in people with low calcium levels. These are [[epileptic seizure|seizures]], [[Cardiac dysrhythmia|severe irregularities in the normal heart beat]], as well as spasm of the [[laryngospasm|upper part of the airways]] or the [[bronchospasm|smaller airways known as the bronchi]] (both potentially causing [[respiratory failure]]).<ref name=Bilezikian/>
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| === Related conditions ===
| | * '''Surgical removal or damage''': The most common cause is accidental damage or removal of the parathyroid glands during [[thyroidectomy]] or other neck surgeries. |
| {| cellpadding="5" | class="wikitable"
| | * '''Autoimmune disease''': The body's immune system may mistakenly attack the parathyroid glands, leading to decreased hormone production. |
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| | * '''Genetic disorders''': Certain genetic conditions, such as [[DiGeorge syndrome]] and familial isolated hypoparathyroidism, can result in hypoparathyroidism. |
| ! colspan="2" | Condition
| | * '''Radiation therapy''': Exposure to radiation, particularly in the treatment of cancers in the neck region, can damage the parathyroid glands. |
| ! Appearance
| | * '''Idiopathic''': In some cases, the cause of hypoparathyroidism is unknown. |
| ! [[parathyroid hormone|PTH]] levels
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| ! [[Calcitriol]]
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| ! [[Calcium]]
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| ! [[Phosphates]]
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| ! [[Genomic imprinting|Imprinting]]
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| |-
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| | colspan="2" | Hypoparathyroidism
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| | Normal
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| | Low
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| | Low
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| | Low
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| | High
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| | Not applicable
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| |-
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| | rowspan="3" | [[Pseudohypoparathyroidism]]
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| | align="center" | Type 1A
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| | [[Albright's hereditary osteodystrophy|Skeletal defects]]
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| | High
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| | Low
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| | Low
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| | High
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| | Gene defect from mother ([[GNAS1]])
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| |-
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| | align="center" | Type 1B
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| | Normal
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| | High
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| | Low
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| | Low
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| | High
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| | Gene defect from mother ([[GNAS1]] and [[STX16]])
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| |-
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| | align="center" | Type 2
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| | Normal
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| | High
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| | Low
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| | Low
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| | High
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| | ?
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| |-
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| | colspan="2" | [[Pseudopseudohypoparathyroidism]]
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| | [[Albright's hereditary osteodystrophy|Skeletal defects]]
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| | Normal
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| | Normal
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| | Normal<ref name="HussainLatif2010">{{cite book|author1=Shahid Hussain|author2=Sharif Aaron Latif|author3=Adrian Hall|title=Rapid Review of Radiology|url=https://books.google.com/books?id=rOliqVIROGcC&pg=PA262|accessdate=30 October 2010|date=1 July 2010|publisher=Manson Publishing|isbn=978-1-84076-120-7|pages=262–}}</ref>
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| | Normal
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| | gene defect from father
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| |}
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| ==Causes== | | ==Symptoms== |
| Hypoparathyroidism can have the following causes:<ref name=Bilezikian/>
| | The symptoms of hypoparathyroidism are primarily due to low calcium levels and may include: |
| * Removal of, or trauma to, the parathyroid glands due to [[thyroid]] surgery ([[thyroidectomy]]), parathyroid surgery (parathyroidectomy) or other surgical interventions in the central part of the neck (such as operations on the larynx and/or pharynx) is a recognized cause. It is the most common cause of hypoparathyroidism. Although [[surgery|surgeon]]s generally make attempts to spare normal parathyroid glands at surgery, inadvertent injury to the glands or their blood supply is still common. When this happens, the parathyroids may cease functioning. This is usually temporary but occasionally long term (permanent).
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| *[[Kenny-Caffey Syndrome]]
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| * [[Autoimmune disorder|Autoimmune]] invasion and destruction is the most common non-surgical cause. It can occur as part of [[autoimmune polyendocrine syndrome]]s.
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| * [[Hemochromatosis]] can lead to iron accumulation and consequent dysfunction of a number of endocrine organs, including the parathyroids.
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| * Absence or dysfunction of the parathyroid glands is one of the components of [[Chromosome 22, microdeletion 22 q11|chromosome 22q11 microdeletion syndrome]] (other names: DiGeorge syndrome, Schprintzen syndrome, velocardiofacial syndrome).
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| * [[Magnesium deficiency (medicine)|Magnesium deficiency]]
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| * A defect in the calcium receptor leads to a rare congenital form of the disease
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| * Idiopathic (of unknown cause), occasionally familial (e.g. [[Barakat syndrome]] (HDR syndrome) a genetic development disorder resulting in hypoparathyroidism, sensorineural deafness, and kidney disease)
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| ==Mechanism==
| | * '''Muscle cramps and spasms''': Known as [[tetany]], these are often painful and can affect any muscle group. |
| The parathyroid glands are so named because they are usually located behind the [[thyroid|thyroid gland]] in the neck. They arise during [[human embryogenesis|fetal development]] from structures known as the third and fourth [[Pharyngeal pouch (embryology)|pharyngeal pouch]]. The glands, usually four in number, contain the [[parathyroid chief cell]]s that sense the level of [[calcium in biology|calcium]] in the blood through the [[calcium-sensing receptor]] and secrete parathyroid hormone. [[Magnesium]] is required for PTH secretion. Under normal circumstances, the parathyroids secrete PTH to maintain a calcium level within normal limits, as calcium is required for adequate muscle and nerve function (including the [[autonomic nervous system]]). PTH acts on several organs to increase calcium levels. It increases calcium absorption in the bowel, while in the kidney it prevents calcium excretion and increases phosphate release and in bone it increases calcium through bone resorption.{{citation needed | date=November 2011}}
| | * '''Paresthesia''': Tingling or "pins and needles" sensations, particularly in the lips, fingers, and toes. |
| | * '''Fatigue and weakness''': General feelings of tiredness and lack of energy. |
| | * '''Anxiety and depression''': Mood changes can occur due to the effects of low calcium on the nervous system. |
| | * '''Seizures''': In severe cases, low calcium levels can lead to seizures. |
| | * '''Cataracts''': Long-term hypocalcemia can lead to the development of cataracts. |
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| ==Diagnosis== | | ==Diagnosis== |
| Diagnosis is by measurement of [[calcium]], [[serum albumin]] (for correction) and PTH in [[blood test|blood]]. | | Diagnosis of hypoparathyroidism involves: |
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| If necessary, measuring [[Cyclic adenosine monophosphate|cAMP]] (cyclic AMP) in the urine after an intravenous dose of PTH can help in the distinction between hypoparathyroidism and other causes.{{citation needed | date=November 2011}}
| | * '''Blood tests''': To measure levels of calcium, phosphorus, magnesium, and parathyroid hormone. |
| | | * '''Urine tests''': To assess calcium excretion. |
| Differential diagnoses are:{{citation needed | date=November 2011}}
| | * '''Genetic testing''': In cases where a hereditary cause is suspected. |
| * [[Pseudohypoparathyroidism]] (normal PTH levels but tissue insensitivity to the hormone, associated with [[intellectual disability]] and [[skeleton|skeletal deformities]]) and [[pseudopseudohypoparathyroidism]].
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| * [[Vitamin D#Deficiency|Vitamin D deficiency]] or hereditary insensitivity to this vitamin (X-linked dominant). | |
| * [[Malabsorption]] | |
| * [[Kidney disease]]
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| * Medication: [[steroid]]s, [[diuretic]]s, some [[antiepileptic]]s.
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| Other tests include [[ECG]] for abnormal heart rhythms, and measurement of blood magnesium levels.{{citation needed | date=November 2011}}
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| ==Treatment== | | ==Treatment== |
| Severe hypocalcaemia, a potentially life-threatening condition, is treated as soon as possible with [[intravenous]] [[calcium]] (e.g. as [[calcium gluconate]]). Generally, a central venous catheter is recommended, as the calcium can irritate [[peripheral vein]]s and cause [[phlebitis]]. In the event of a life-threatening attack of low calcium levels or tetany (prolonged muscle contractions), calcium is administered by intravenous (IV) infusion. Precautions are taken to prevent seizures or larynx spasms. The heart is monitored for abnormal rhythms until the person is stable. When the life-threatening attack has been controlled, treatment continues with medicine taken by mouth as often as four times a day.{{citation needed | date=November 2011}}
| | The primary goal of treatment is to restore and maintain normal calcium levels. Treatment options include: |
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| Long-term treatment of hypoparathyroidism is with [[vitamin D]] analogs and calcium supplementation, but may be ineffective in some due to potential renal damage.<ref>Winer KK, Yanovski JA, Cutler GB Jr. Synthetic human parathyroid hormone 1-34 vs calcitriol and calcium in the treatment of hypoparathyroidism: Results of a randomized crossover trial" ''JAMA'' 1996;276:631-636</ref> The N-terminal fragment of parathyroid hormone (PTH 1-34) has full [[biological activity]]. The use of pump delivery of synthetic PTH 1-34 provides the closest approach to physiologic PTH replacement therapy.<ref>Winer KK, Zhang B, Shrader J, et al. Synthetic human parathyroid hormone 1-34 replacement therapy: A randomized crossover trial comparing pump versus injections in the treatment of chronic hypoparathyroidism. J Clin Endocrinol Metab. Nov.2011.</ref> Injections of [[recombinant human parathyroid hormone]] are available as treatment in those with low blood calcium levels.<ref>{{cite web|title=FDA approves Natpara to control low blood calcium levels in patients with hypoparathyroidism|url=https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm431358.htm|website=fda.gov/|accessdate=30 January 2015}}</ref>
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| ==See also==
| | * '''Calcium supplements''': Oral calcium carbonate or calcium citrate is often prescribed. |
| * [[Hyperparathyroidism]] | | * '''Vitamin D analogs''': Such as calcitriol, to help increase calcium absorption from the gut. |
| | * '''Thiazide diuretics''': These may be used to reduce urinary calcium excretion. |
| | * '''Recombinant human parathyroid hormone''': In some cases, synthetic PTH may be administered. |
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| ==References== | | ==Prognosis== |
| {{reflist}}
| | With appropriate treatment, individuals with hypoparathyroidism can lead normal lives. However, lifelong monitoring and medication may be necessary to maintain calcium levels and prevent complications. |
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| == External links == | | ==Related pages== |
| {{Medical resources
| | * [[Parathyroid hormone]] |
| | DiseasesDB = 6490
| | * [[Hypocalcemia]] |
| | ICD10 = {{ICD10|E|20||e|20}}, {{ICD10|E|89|2|e|70}}, {{ICD10|P|71|4|p|70}}
| | * [[Thyroidectomy]] |
| | ICD9 = {{ICD9|252.1}}
| | * [[DiGeorge syndrome]] |
| | OMIM = 146200
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| | MedlinePlus = 000385
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| | eMedicineSubj = med
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| | eMedicineTopic = 1131
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| | eMedicine_mult = {{eMedicine2|emerg|276}} {{eMedicine2|ped|1125}}
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| | MeshID = D007011
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| }}
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| {{Endocrine pathology}}
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| {{Medicine}}
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| | [[Category:Endocrine disorders]] |
| | [[Category:Calcium metabolism]] |
| [[Category:Parathyroid disorders]] | | [[Category:Parathyroid disorders]] |
| [[Category:Endocrine-related cutaneous conditions]]
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| [[Category:Rare diseases]]
| |
Endocrine disorder characterized by low levels of parathyroid hormone
Hypoparathyroidism
Hypoparathyroidism is an endocrine disorder characterized by insufficient production of parathyroid hormone (PTH) by the parathyroid glands. This condition leads to low levels of calcium in the blood, a condition known as hypocalcemia, and can result in a variety of symptoms and complications.
Causes
Hypoparathyroidism can be caused by several factors, including:
- Surgical removal or damage: The most common cause is accidental damage or removal of the parathyroid glands during thyroidectomy or other neck surgeries.
- Autoimmune disease: The body's immune system may mistakenly attack the parathyroid glands, leading to decreased hormone production.
- Genetic disorders: Certain genetic conditions, such as DiGeorge syndrome and familial isolated hypoparathyroidism, can result in hypoparathyroidism.
- Radiation therapy: Exposure to radiation, particularly in the treatment of cancers in the neck region, can damage the parathyroid glands.
- Idiopathic: In some cases, the cause of hypoparathyroidism is unknown.
Symptoms
The symptoms of hypoparathyroidism are primarily due to low calcium levels and may include:
- Muscle cramps and spasms: Known as tetany, these are often painful and can affect any muscle group.
- Paresthesia: Tingling or "pins and needles" sensations, particularly in the lips, fingers, and toes.
- Fatigue and weakness: General feelings of tiredness and lack of energy.
- Anxiety and depression: Mood changes can occur due to the effects of low calcium on the nervous system.
- Seizures: In severe cases, low calcium levels can lead to seizures.
- Cataracts: Long-term hypocalcemia can lead to the development of cataracts.
Diagnosis
Diagnosis of hypoparathyroidism involves:
- Blood tests: To measure levels of calcium, phosphorus, magnesium, and parathyroid hormone.
- Urine tests: To assess calcium excretion.
- Genetic testing: In cases where a hereditary cause is suspected.
Treatment
The primary goal of treatment is to restore and maintain normal calcium levels. Treatment options include:
- Calcium supplements: Oral calcium carbonate or calcium citrate is often prescribed.
- Vitamin D analogs: Such as calcitriol, to help increase calcium absorption from the gut.
- Thiazide diuretics: These may be used to reduce urinary calcium excretion.
- Recombinant human parathyroid hormone: In some cases, synthetic PTH may be administered.
Prognosis
With appropriate treatment, individuals with hypoparathyroidism can lead normal lives. However, lifelong monitoring and medication may be necessary to maintain calcium levels and prevent complications.
Related pages
