Hypercalcaemia

Hypercalcaemia, also spelled hypercalcemia, is a high calcium (Ca2+) level in the blood serum.[1][3] 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.[1][2][4] Those with a mild increase that has developed slowly typically have no symptoms.[1] 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.[1][2]

Most cases are due to primary hyperparathyroidism or cancer.[1] Other causes include sarcoidosis, tuberculosis, Paget disease, multiple endocrine neoplasia (MEN), vitamin D toxicity, familial hypocalciuric hypercalcaemia, and certain medications such as lithium and hydrochlorothiazide.[1][2][3] Diagnosis should generally include either a corrected calcium or ionized calcium level and be confirmed after a week.[1] Specific changes, such as a shortened QT interval and prolonged PR interval, may be seen on an electrocardiogram (ECG).[2]

Treatment may include intravenous fluids, furosemide, calcitonin, or pamidronate in addition to treating the underlying cause.[1][2] The evidence for furosemide, however, is poor.[1] In those with very high levels hospitalization may be required.[1] Hemodialysis may be used in those who do not respond to other treatments.[1] In those with vitamin D toxicity steroids may be useful.[1] Hypercalcemia is relatively common.[1] Primary hyperparathyroidism occurs in between one and seven per thousand people and hypercalcemia occurs in about 2.7% of those with cancer.[1]

Hypercalcaemia
Other namesHypercalcemia
Ca-TableImage
Calcium within the periodic table
SpecialtyEndocrinology
SymptomsAbdominal pain, bone pain, confusion, depression, weakness[1][2]
ComplicationsKidney stones, abnormal heart rhythm, cardiac arrest[1][2]
CausesPrimary hyperparathyroidism, cancer, sarcoidosis, tuberculosis, Paget disease, multiple endocrine neoplasia, vitamin D toxicity[1][3]
Diagnostic methodBlood serum level > 2.6 mmol/l (corrected calcium or ionized calcium)[1][2]
TreatmentUnderlying cause, intravenous fluids, furosemide, calcitonin, pamidronate, hemodialysis[1][2]
Frequency4 per 1,000[1]

Signs and symptoms

The neuromuscular symptoms of hypercalcemia are caused by a negative bathmotropic effect due to the increased interaction of calcium with sodium channels. Since calcium blocks sodium channels and inhibits depolarization of nerve and muscle fibers, increased calcium raises the threshold for depolarization.[5] This results in diminished deep tendon reflexes (hyporeflexia), and skeletal muscle weakness.[6] There is a general mnemonic for remembering the effects of hypercalcaemia: "Stones, Bones, Groans, Thrones and Psychiatric Overtones"

Other symptoms include cardiac arrhythmias (especially in those taking digoxin), fatigue, nausea, vomiting (emesis), anorexia, abdominal pain, constipation, & paralytic ileus. If renal impairment occurs as a result, manifestations can include polyuria, nocturia, and polydipsia.[6] Psychiatric manifestation can include emotional instability, confusion, delirium, psychosis, & stupor.[6] Limbus sign seen in eye due to hypercalcemia.

Hypercalcemia can result in an increase in heart rate[7] and a positive inotropic effect (increase in contractility).

Symptoms are more common at high calcium blood values (12.0 mg/dl or 3 mmol/l).[6] Severe hypercalcaemia (above 15–16 mg/dl or 3.75–4 mmol/l) is considered a medical emergency: at these levels, coma and cardiac arrest can result. The high levels of calcium ions decrease the neuron membrane permeability to sodium ions, thus decreasing excitability, which leads to hypotonicity of smooth and striated muscle. This explains the fatigue, muscle weakness, low tone and sluggish reflexes in muscle groups. The sluggish nerves also explain drowsiness, confusion, hallucinations, stupor and / or coma. In the gut this causes constipation. Hypocalcaemia causes the opposite by the same mechanism.

Causes

Primary hyperparathyroidism and malignancy account for about 90% of cases of hypercalcaemia.[8][9]

Parathyroid function

Cancer

Small cell carcinoma of the ovary hypercalcemic type - high mag
Micrograph of ovarian small cell carcinoma of the hypercalcemic type. H&E stain.

Vitamin-D disorders

High bone-turnover rates

Kidney failure

Other

Diagnosis

ECG changes

An Osborn wave, an abnormal EKG tracing that can be associated with hypercalcemia.

Abnormal heart rhythms can also result, and ECG findings of a short QT interval[16] suggest hypercalcaemia. Significant hypercalcaemia can cause ECG changes mimicking an acute myocardial infarction.[17] Hypercalcaemia has also been known to cause an ECG finding mimicking hypothermia, known as an Osborn wave.[18]

Treatments

The goal of therapy is to treat the hypercalcaemia first and subsequently effort is directed to treat the underlying cause.

Fluids and diuretics

Initial therapy:

  • hydration, increasing salt intake, and forced diuresis.
    • hydration is needed because many patients are dehydrated due to vomiting or kidney defects in concentrating urine.
    • increased salt intake also can increase body fluid volume as well as increasing urine sodium excretion, which further increases urinary potassium excretion.
    • after rehydration, a loop diuretic such as furosemide can be given to permit continued large volume intravenous salt and water replacement while minimizing the risk of blood volume overload and pulmonary oedema. In addition, loop diuretics tend to depress calcium reabsorption by the kidney thereby helping to lower blood calcium levels
    • can usually decrease serum calcium by 1–3 mg/dL within 24 hours
    • caution must be taken to prevent potassium or magnesium depletion

Bisphosphonates and calcitonin

Additional therapy:

  • bisphosphonates are pyrophosphate analogues with high affinity for bone, especially areas of high bone-turnover.
    • they are taken up by osteoclasts and inhibit osteoclastic bone resorption
    • current available drugs include (in order of potency): (1st gen) etidronate, (2nd gen) tiludronate, IV pamidronate, alendronate (3rd gen) zoledronate and risedronate
    • all people with cancer-associated hypercalcaemia should receive treatment with bisphosphonates since the 'first line' therapy (above) cannot be continued indefinitely nor is it without risk. Further, even if the 'first line' therapy has been effective, it is a virtual certainty that the hypercalcaemia will recur in the person with hypercalcaemia of malignancy. Use of bisphosphonates in such circumstances, then, becomes both therapeutic and preventative
    • people in kidney failure and hypercalcaemia should have a risk-benefit analysis before being given bisphosphonates, since they are relatively contraindicated in kidney failure.
  • Calcitonin blocks bone resorption and also increases urinary calcium excretion by inhibiting calcium reabsorption by the kidney
    • Usually used in life-threatening hypercalcaemia along with rehydration, diuresis, and bisphosphonates
    • Helps prevent recurrence of hypercalcaemia
    • Dose is 4 international units per kilogram via subcutaneous or intramuscular route every 12 hours, usually not continued indefinitely due to quick onset of decreased response to calcitonin

Other therapies

Hypercalcaemic crisis

A hypercalcaemic crisis is an emergency situation with a severe hypercalcaemia, generally above approximately 14 mg/dL (or 3.5 mmol/l).[19]

The main symptoms of a hypercalcaemic crisis are oliguria or anuria, as well as somnolence or coma.[20] After recognition, primary hyperparathyroidism should be proved or excluded.[20]

In extreme cases of primary hyperparathyroidism, removal of the parathyroid gland after surgical neck exploration is the only way to avoid death.[20] The diagnostic program should be performed within hours, in parallel with measures to lower serum calcium.[20] Treatment of choice for acutely lowering calcium is extensive hydration and calcitonin, as well as bisphosphonates (which have effect on calcium levels after one or two days).[21]

Other animals

Research has led to a better understanding of hypercalcemia in non-human animals. Often the causes of hypercalcemia have a correlation to the environment in which the organisms live. Hypercalcemia in house pets is typically due to disease, but other cases can be due to accidental ingestion of plants or chemicals in the home.[22] Outdoor animals commonly develop hypercalcemia through vitamin D toxicity from wild plants within their environments.[23]

Household pets

Household pets such as dogs and cats are found to develop hypercalcemia. It is less common in cats, and many feline cases are idiopathic.[22] In dogs, lymphosarcoma, addison’s disease, primary hyperparathyroidism, and chronic renal failure are the main causes of hypercalcemia, but there are also environmental causes usually unique to indoor pets.[22] Ingestion of small amounts of calcipotriene found in psoriasis cream can be fatal to a pet.[24] Calcipotriene causes a rapid rise in calcium ion levels.[24] Calcium ion levels can remain high for weeks if untreated and lead to an array of medical issues.[24] There are also cases of hypercalcemia reported due to dogs ingesting rodenticides containing a chemical similar to calcipotriene found in psoriasis cream.[24] Additionally, ingestion of household plants is a cause of hypercalcemia. Plants such as Cestrum diurnum, and Solanum malacoxylon contain ergocalciferol or cholecalciferol which cause the onset of hypercalcemia.[22] Consuming small amounts of these plants can be fatal to pets. Observable symptoms may develop such as polydipsia, polyuria, extreme fatigue, or constipation.[22]

Outdoor animals

Trisetum.flavescens2.-.lindsey
Trisetum flavescens (yellow oat grass)

In certain outdoor environments, animals such as horses, pigs, cattle, and sheep experience hypercalcemia commonly. In southern Brazil and Mattewara India, approximately 17 percent of sheep are affected, with 60 percent of these cases being fatal.[23] Many cases are also documented in Argentina, Papua-New Guinea, Jamaica, Hawaii, and Bavaria.[23] These cases of hypercalcemeia are usually caused by ingesting Trisetum flavescens before it has dried out.[23] Once Trisetum flavescens is dried out, the toxicity of it is diminished.[23] Other plants causing hypercalcemia are Cestrum diurnum, Nierembergia veitchii, Solanum esuriale, Solanum torvum, and Solanum malacoxylon.[23] These plants contain calcitriol or similar substances that cause rises in calcium ion levels.[23] Hypercalcemia is most common in grazing lands at altitudes above 1500 meters where growth of plants like Trisetum flavescens is favorable.[23] Even if small amounts are ingested over long periods of time, the prolonged high levels of calcium ions have large negative effects on the animals.[23] The issues these animals experience are muscle weakness, and calcification of blood vessels, heart valves, liver, kidneys, and other soft tissues, which eventually can lead to death.[23]

See also

References

  1. ^ a b c d e f g h i j k l m n o p q r s t Minisola, S; Pepe, J; Piemonte, S; Cipriani, C (2015). "The diagnosis and management of hypercalcaemia". BMJ. 350: h2723. doi:10.1136/bmj.h2723. PMID 26037642.
  2. ^ a b c d e f g h i Soar, Jasmeet; Perkins, Gavin D; Abbas, Gamal; Alfonzo, Annette; Barelli, Alessandro; Bierens, Joost J.L.M; Brugger, Hermann; Deakin, Charles D; Dunning, Joel; Georgiou, Marios; Handley, Anthony J; Lockey, David J; Paal, Peter; Sandroni, Claudio; Thies, Karl-Christian; Zideman, David A; Nolan, Jerry P (2010). "European Resuscitation Council Guidelines for Resuscitation 2010 Section 8. Cardiac arrest in special circumstances: Electrolyte abnormalities, poisoning, drowning, accidental hypothermia, hyperthermia, asthma, anaphylaxis, cardiac surgery, trauma, pregnancy, electrocution". Resuscitation. 81 (10): 1400–33. doi:10.1016/j.resuscitation.2010.08.015. PMID 20956045.
  3. ^ a b c "Hypercalcemia - National Library of Medicine". PubMed Health. Archived from the original on 8 September 2017. Retrieved 27 September 2016.
  4. ^ "Appendix 1: Conversion of SI Units to Standard Units". Principles and Practice of Geriatric Medicine. 2. 2005. i–ii. doi:10.1002/047009057X.app01. ISBN 978-0-470-09057-2.
  5. ^ Armstrong, C. M; Cota, G (1999). "Calcium block of Na+ channels and its effect on closing rate". Proceedings of the National Academy of Sciences. 96 (7): 4154–7. doi:10.1073/pnas.96.7.4154. PMC 22436. PMID 10097179.
  6. ^ a b c d "Hypercalcemia". Merck Manual. Archived from the original on July 13, 2017. Retrieved June 10, 2017.
  7. ^ "Archived copy" (PDF). Archived (PDF) from the original on 2016-03-25. Retrieved 2016-03-17.CS1 maint: Archived copy as title (link)
  8. ^ Table 20-4 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). Robbins Basic Pathology (8th ed.). Philadelphia: Saunders. ISBN 978-1-4160-2973-1.
  9. ^ Tierney, Lawrence M.; McPhee, Stephen J.; Papadakis, Maxine A. (2006). Current Medical Diagnosis and Treatment 2007 (Current Medical Diagnosis and Treatment). McGraw-Hill Professional. p. 901. ISBN 978-0-07-147247-0.
  10. ^ Online Mendelian Inheritance in Man (OMIM) 146200
  11. ^ Online Mendelian Inheritance in Man (OMIM) 145980
  12. ^ Online Mendelian Inheritance in Man (OMIM) 145981
  13. ^ Online Mendelian Inheritance in Man (OMIM) 600740
  14. ^ Non-Small Cell Lung Cancer~clinical at eMedicine.
  15. ^ Online Mendelian Inheritance in Man (OMIM) 143880
  16. ^ "Archived copy". Archived from the original on 2014-12-16. Retrieved 2014-10-19.CS1 maint: Archived copy as title (link)
  17. ^ Wesson, L; Suresh, V; Parry, R (2009). "Severe hypercalcaemia mimicking acute myocardial infarction". Clinical Medicine. 9 (2): 186–7. doi:10.7861/clinmedicine.9-2-186. PMC 4952678. PMID 19435131.
  18. ^ Serafi, Sami W; Vliek, Crystal; Taremi, Mahnaz (2012). "Osborn waves in a hypothermic patient". Journal of Community Hospital Internal Medicine Perspectives. 1 (4): 10742. doi:10.3402/jchimp.v1i4.10742. PMC 3714046. PMID 23882340.
  19. ^ Hypercalcemia in Emergency Medicine Archived 2011-04-25 at the Wayback Machine at Medscape. Author: Robin R Hemphill. Chief Editor: Erik D Schraga. Retrieved April 2011
  20. ^ a b c d Ziegler R (February 2001). "Hypercalcemic crisis". J. Am. Soc. Nephrol. 12 Suppl 17: S3–9. PMID 11251025.
  21. ^ Page 394 Archived 2017-09-08 at the Wayback Machine in: Roenn, Jamie H. Von; Ann Berger; Shuster, John W. (2007). Principles and practice of palliative care and supportive oncology. Hagerstwon, MD: Lippincott Williams & Wilkins. ISBN 978-0-7817-9595-1.
  22. ^ a b c d e Hypercalcemia in Dogs and Cats Archived 2014-07-28 at the Wayback Machine Peterson DVM, DACVIM. M. E., July 2013. Hypercalcemia in Dogs and Cats. The Merck Veternary Manual. Merck Sharp & Dohme, Whitehouse Station, NJ, USA.
  23. ^ a b c d e f g h i j Enzootic Calcinosis Archived 2014-07-28 at the Wayback Machine Gruenberg MS, PhD, DECAR DECBHM. W.G., April 2014. Enzootic Calcinosis. The Merck Veternary Manual. Merck Sharp & Dohme, Whitehouse Station, NJ, USA.
  24. ^ a b c d Topical Agents (Toxicity) Archived 2014-07-28 at the Wayback Machine Khan DVM, MS, PhD, DABVT, S.A., March 2012. Topical Agents (Toxicity). The Merck Veternary Manual. Merck Sharp & Dohme, Whitehouse Station, NJ, USA.

External links

External resources
Anal sac adenocarcinoma

An anal sac adenocarcinoma is an uncommon and aggressive malignant tumor found in dogs that arises from the apocrine glandular tissue of anal sac. The disease exists in cats as well, but is much less common in that species. They are the second most common cancerous cause of hypercalcaemia (high serum calcium) in dogs, following T-cell lymphoma.

Bisphosphonate

Bisphosphonates are a class of drugs that prevent the loss of bone density, used to treat osteoporosis and similar diseases. They are the most commonly prescribed drugs used to treat osteoporosis. They are called bisphosphonates because they have two phosphonate (PO(OH)2) groups. They are thus also called diphosphonates (bis- or di- + phosphonate).

Evidence shows that they reduce the risk of fracture in post-menopausal women with osteoporosis.Bone tissue undergoes constant remodeling and is kept in balance (homeostasis) by osteoblasts creating bone and osteoclasts destroying bone. Bisphosphonates inhibit the digestion of bone by encouraging osteoclasts to undergo apoptosis, or cell death, thereby slowing bone loss.The uses of bisphosphonates include the prevention and treatment of osteoporosis, Paget's disease of bone, bone metastasis (with or without hypercalcaemia), multiple myeloma, primary hyperparathyroidism, osteogenesis imperfecta, fibrous dysplasia, and other conditions that exhibit bone fragility.

Bladder stone (animal)

Bladder stones or uroliths are a common occurrence in animals, especially in domestic animals such as dogs and cats. Occurrence in other species, including tortoises, has been reported as well. The stones form in the urinary bladder in varying size and numbers secondary to infection, dietary influences, and genetics. Stones can form in any part of the urinary tract in dogs and cats, but unlike in humans, stones of the kidney are less common and do not often cause significant disease, although they can contribute to pyelonephritis and chronic renal failure. Types of stones include struvite, calcium oxalate, urate, cystine, calcium phosphate, and silicate. Struvite and calcium oxalate stones are by far the most common.

Calcipotriol

Calcipotriol, also known as calcipotriene, is a synthetic derivative of calcitriol, a form of vitamin D. It is used in the treatment of psoriasis. It is safe for long-term application in psoriatic skin conditions.

It was patented in 1985 and approved for medical use in 1991. It is marketed under the trade name "Dovonex" in the United States, "Daivonex" outside North America, and "Psorcutan" in Germany.

Calcium/cholecalciferol

Calcium/cholecalciferol is a combination of a calcium salt (usually calcium carbonate) and vitamin D3 (cholecalciferol). It is used to prevent and treat lack of calcium and vitamin D in the elderly, as well for osteoporosis in combination with other medications.In 2016 it was the 183rd most prescribed medication in the United States with more than 3 million prescriptions. It is available under many brand names and in many forms such as chewable tablets, coated tablets, and effervescent tablets.

Calculus (medicine)

A calculus (plural calculi), often called a stone, is a concretion of material, usually mineral salts, that forms in an organ or duct of the body. Formation of calculi is known as lithiasis (). Stones can cause a number of medical conditions.

Some common principles (below) apply to stones at any location, but for specifics see the particular stone type in question.

Calculi are not to be confused with gastroliths.

Catatonia

Catatonia is a state of psycho-motor immobility and behavioral abnormality manifested by stupor. It was first described in 1874 by Karl Ludwig Kahlbaum, in German: Die Katatonie oder das Spannungsirresein (Catatonia or Tension Insanity).

Though catatonia has historically been related to schizophrenia (catatonic schizophrenia), it is now known that catatonic symptoms are nonspecific and may be observed in other mental disorders and neurological conditions. In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM), catatonia is not recognized as a separate disorder, but is associated with psychiatric conditions such as schizophrenia (catatonic type), bipolar disorder, post-traumatic stress disorder, depression and other mental disorders, narcolepsy, as well as drug abuse or overdose (or both). It may also be seen in many medical disorders including infections (such as encephalitis), autoimmune disorders, focal neurologic lesions (including strokes), metabolic disturbances, alcohol withdrawal and abrupt or overly rapid benzodiazepine withdrawal. In the fifth edition of the DSM, it is written that a variety of medical conditions may cause catatonia, especially neurological conditions: encephalitis, cerebrovascular disease, neoplasms, head injury. Moreover, metabolic conditions: homocystinuria, diabetic ketoacidosis, hepatic encephalopathy, hypercalcaemia.It can be an adverse reaction to prescribed medication. It bears similarity to conditions such as encephalitis lethargica and neuroleptic malignant syndrome. There are a variety of treatments available; benzodiazepines are a first-line treatment strategy. Electroconvulsive therapy is also sometimes used. There is growing evidence for the effectiveness of NMDA receptor antagonists for benzodiazepine-resistant catatonia. Antipsychotics are sometimes employed but require caution as they can worsen symptoms and have serious adverse effects.

Chondrocalcinosis

Chondrocalcinosis or cartilage calcification is calcification (accumulation of calcium salts) in hyaline and/or fibrocartilage. It can be seen on radiography.

Cyclopenthiazide

Cyclopenthiazide (trade name Navidrex) is a thiazide diuretic used in the treatment of heart failure and hypertension.

Disorders of calcium metabolism

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.

Familial hypocalciuric hypercalcemia

Familial hypocalciuric hypercalcemia (FHH) is an inherited condition that can cause hypercalcemia, a serum calcium level typically above 10.2 mg/dL. 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.

Genta (company)

Genta Inc. was a biopharmaceutical company based in Berkeley Heights, New Jersey, United States, which developed products for the treatment of patients with cancer. In August 2012, the company filed for bankruptcy.

HHMS

The abbreviation HHMS may refer to:

The location indicator for Massawa International Airport

His Hawaiian Majesty's Ship - a ship designation

His Hellenic Majesty's Ship - a ship designation

Highland Hills Middle School

Hand Held Message Service - a byte-oriented messaging protocol

Humoral hypercalcaemia of malignancy syndrome

Hypercalciuria

Hypercalciuria is the condition of elevated calcium in the urine. Chronic hypercalcinuria may lead to impairment of renal function, nephrocalcinosis, and renal insufficiency. Patients with hypercalciuria have kidneys that put out higher levels of calcium than normal. Calcium may come from one of two paths: through the gut where higher than normal levels of calcium are absorbed by the body or from the bones. A bone density scan (DSX) may be performed to determine if calcium is obtained from the bones.

Hypercalciuria in patients can be due to genetic causes.

Jansen's metaphyseal chondrodysplasia

Jansen's metaphyseal chondrodysplasia (JMC) is a disease that results from ligand-independent activation of the type 1 (PTH1R) of the parathyroid hormone receptor, due to one of three reported mutations (activating mutation).

JMC is extremely rare, and as of 2007 there are fewer than 20 reported cases worldwide.

There are only 2 known families, from Dubai and Texas, in which the disease was passed from mother to daughter (Texas), and from a mother to her 2 sons (Dubai).

www.thejansensfoundation.org

Oncological emergencies

Oncological emergencies are a group of conditions that occur as a direct or indirect result of cancer or its treatment that are potentially life-threateningThese include:

Hypercalcaemia

Neutropaenic sepsis

Tumour lysis syndrome

Leukostasis

Raised intracranial pressure

Spinal cord compression

Cauda equina syndrome

Superior vena cava obstruction

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Disseminated intravascular coagulation

Parathyroid hormone

Parathyroid hormone (PTH), also called parathormone or parathyrin, is a hormone secreted by the parathyroid glands that regulates the serum calcium through its effects on bone, kidney, and intestine.PTH influences bone remodeling, which is an ongoing process in which bone tissue is alternately resorbed and rebuilt over time. PTH is secreted in response to low blood serum calcium (Ca2+) levels. PTH indirectly stimulates osteoclast activity within the bone matrix (osteon), in an effort to release more ionic calcium (Ca2+) into the blood to elevate a low serum calcium level. The bones act as a (metaphorical) "bank of calcium" from which the body can make "withdrawals" as needed to keep the amount of calcium in the blood at appropriate levels despite the ever-present challenges of metabolism, stress, and nutritional variations. PTH is "a key that unlocks the bank vault" to remove the calcium.

PTH is secreted primarily by the chief cells of the parathyroid glands. It is a polypeptide containing 84 amino acids, which is a prohormone. It has a molecular mass around 9500 Da. Its action is opposed by the hormone calcitonin.

There are two types of PTH receptors. Parathyroid hormone 1 receptors, activated by the 34 N-terminal amino acids of PTH, are present at high levels on the cells of bone and kidney. Parathyroid hormone 2 receptors are present at high levels on the cells of central nervous system, pancreas, testes, and placenta. The half-life of PTH is about 4 minutes.Disorders that yield too little or too much PTH, such as hypoparathyroidism, hyperparathyroidism, and paraneoplastic syndromes can cause bone disease, hypocalcaemia, and hypercalcaemia.

Paricalcitol

Paricalcitol (chemically it is 19-nor-1,25-(OH)2-vitamin D2. Marketed by Abbott Laboratories under the trade name Zemplar) is a drug used for the prevention and treatment of secondary hyperparathyroidism (excessive secretion of parathyroid hormone) associated with chronic renal failure. It is an analog of 1,25-dihydroxyergocalciferol, the active form of vitamin D2 (ergocalciferol).

It was patented in 1989 and approved for medical use in 1998.

Stella Malucchi

Stella Malucchi (Thai: สเตลล่า มาลูกี้) is an Italian-Colombian model and actress. Fluent in the Thai language, she has primarily worked in Thailand, and has acted in two films, Tears of the Black Tiger and Angulimala.

For her first film, Tears of the Black Tiger, she was spotted in a Thai music video by director Wisit Sasanatieng, who thought she would be perfect for the role of Rumpoey. Through make-up and costuming, Malucchi was transformed into a young, noble-born Thai woman in 1950s Thailand. She studied at Ruamrudee International School.

Stella fell ill one week after she gave birth to her son on Jan 2, and was admitted into hospital On Jan 24, 2010. After being directly admitted into ICU, she lost consciousness and lapsed into a coma. Tests revealed that she had hyperparathyroidism, a rare disease in which a defective parathyroid gland allows dangerously high calcium levels (hypercalcaemia). Being too weak for an operation to remove her parathyroid, she was placed on an artificial lung and heart machine. After five days and requiring dialysis several times a day, Stella showed signs of improvement. Unfortunately, complications soon developed. A restricted blood-flow to her right leg caused infection and an above-the-knee amputation was required. Soon after the removal of the leg, and with signs of infection having disappeared, Stella's parathyroid gland was then safely removed, ensuring her survival. Stella woke from the coma one month after she was admitted.

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