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Overview |
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Definition |
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Hypoparathyroidism is a relatively rare endocrine disorder (affecting 0.6% of
the population) characterized by either insufficient production of parathyroid
hormone (PTH), the inability to make an active form of PTH, or the inability of
kidneys and bones to respond to PTH production (pseudohypoparathyroidism). The
hereditary form is marked by either an absence or a malfunction of the
parathyroid glands and may be inherited through an autosomal recessive gene or
may result from any of several genetic abnormalities. Most cases of
hypoparathyroidism are acquired as a result of surgical resection of parathyroid
glands, although there are other potential causes (see below).
Hypoparathyroidism results in hypocalcemia and hyperphosphatemia. It is usually
chronic, although, in the case of congenital hypophosphatemia, spontaneous
remission can occur within the first 24 months of life. |
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Etiology |
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Iatrogenic:
- Massive radiation to the thyroid gland
- Drugs
- Surgical resection of parathyroid adenoma or near total
parathyroidectomy—currently the most common cause of
acquired hypoparathyroidism
- Thyroidectomy—formerly the most common cause
of acquired hypoparathyroidism; frequently results in transient
hypoparathyroidism, sometimes lasting months
Congenital:
- Parathyroid aplasia
- DiGeorge syndrome—rare; lack of embryologic
formation of parathyroid glands and thymus; consequence is usually early death
secondary to infection because of T-cell deficiency, seizures from low calcium,
or cardiovascular complications; sporadic occurence
Parathyroid gland suppression:
- Hypomagnesemia
- Drugs (aluminum containing antacids, asparagine, doxorubicin, cytosine
arabinoside, cimetidine)
Infiltration or destruction of the parathyroid glands:
- Metastatic carcinoma
- Wilson's disease
- Sarcoidosis
- Hemochromatosis; hemosiderosis
- Neck trauma
- Radiation—unusual; e.g. following radioiodine
treatment for hyperthyroidism
- Autoimmune polyglandular syndrome type 1 (early
onset)—involves adrenals and ovaries as well;
associated with vitiligo, pernicious anemia, alopecia, and mucocutaneous
candidal infections; antibodies present to endocrine organs; autosomal recessive
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Risk Factors |
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- Genetic
- Massive radiation to the thyroid gland
- Drugs
- Surgical resection of parathyroid adenoma
- Parathyroidectomy
- Thyroidectomy
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Signs and Symptoms |
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Vary depending on degree and rate of development of hypocalcemia
- Dry skin; dystrophic nails
- Candidiasis (fingers, toenails, skins, mouth, vagina) (in the case of
autoimmune polyglandular syndrome type 1)
- Chvostek and Trousseau signs
- Tetany, which can lead to laryngeal spasm and associated breathing
difficulties
- Parasthesias, particularly around the mouth and fingers
- Anxiety
- Convulsions or seizures
- Hair loss
- Cataracts
Children may present with the following:
- Poor tooth development
- Vomiting
- Headaches
- Mental deficiency
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Differential
Diagnosis |
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- Causes of hypocalcemia including pancreatitis or
malabsorption
- Causes of hypomagnesemia
- Causes of hyperphosphatemia
- Renal failure
- Pseudohypoparathyroidism
- Vitamin D deficiency
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Diagnosis |
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Physical Examination |
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The patient may have neurological manifestations, including tetany and
seizures and twitching in infants; again, look for Chvostek and Trousseau signs.
Some patients may present with decreased cardiac contractility, which can result
in heart failure. Infants may have vomiting, abdominal distention, apneic
spells, and intermittent cyanosis. Mental retardation may be present in
idiopathic cases. Ectodermal signs include dry skin, thinning hair, dystrophic
nails and candidal infections. May present with alopecia and vitiligo as well.
In pseudohypoparathyroidism, serum calcium may be normal and PTH is generally
high. Patients with congenital pseudohypoparathyroidism tend towards short
stature due to characteristic skeletal abnormalities; also, typical round faces.
Hypoparathyroidism should not be diagnosed immediately after surgery because
inadequate parathyroid hormone production may be temporary, lasting up to a few
months. |
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Laboratory Tests |
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- Typical triad is low calcium, high phosphate, and normal renal
function
- Radioimmunoassay for decreased PTH; will be normal or elevated with
pseudohypoparathyroidism
- Assays for vitamin D metabolites
- Serum magnesium (generally low but may be high)
- Elevated serum bicarbonate
- CBC with RBC indices as well as B12 levels; evaluate for pernicious
anemia
- Defective urinary cAMP response to administration of exogenous PTH in
the case of pseudohypoparathyroidism
- Presence of antibodies to endocrine
organs
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Pathology/Pathophysiology |
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- Possible presence of rickets and a variety of other neuromuscular
syndromes and deformities
- Deficiency of a guanine nucleotide including regulatory protein in
erythrocytes and other tissues (pseudohypoparathyroidism)
- Shortened metacarpal (usually the 1st, 4th, and 5th metacarpals) and
metatarsal bones, short stature
(pseudohypoparathyroidism)
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Imaging |
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- X-ray findings include premature closing of epiphyses, generalized
increase in bone density, and absent tooth roots
- CT scans reveal soft tissue abnormalities, including calcifications of
basal ganglia, choroid plexus, and cerebellum (idiopathic)
- Pseudohypoparathyroidism may present with subcutaneous
calcifications
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Other Diagnostic
Procedures |
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- Electrocardiogram (ECG)—prolongation of the
QT interval and terminal T-wave inversion; heart block may be present
- Slit-lamp examination to look for early posterior lenticular cataracts
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Treatment Options |
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Treatment Strategy |
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A lifelong regimen of vitamin D (or calcitriol) and calcium is usually
required to restore calcium and associated mineral balance. Periodic monitoring
ensures correct dosages. Patients should follow a high-calcium, low-phosphorous
diet, and avoid milk and cheese (see Nutrition section). Thiazide
diuretics should be administered in combination with low salt diet when needed
to prevent over-excretion of calcium in the urine, which is important for
decreasing formation of kidney stones. These diuretics may also reduce the
amount of calcium and vitamin D supplements needed. In cases of PTH inactivity
due to hypomagnesemia, a magnesium supplement is used.
- Calcium—Calcium gluconate -- initial
administered intravenously in emergency situations (100 to 300 mg calcium IV in
150 ml dextrose over 10 min) followed by a high-calcium diet and supplementation
if needed (see Nutrition section below). Pediatric patients receive 2
mg/kg of calcium or 0.2 mg of 10% calcium gluconate/kg. Caution should be
exercised in patients with respiratory failure or acidosis and those with severe
hyperphosphatemia. Monitor cardiac function.
- Vitamin
D—ergocalciferol—adults
(25,000 to 200,000 IU/day orally); pediatrics (50,000 to 200,000 IU/day orally);
contraindicated in cases of hypercalcemia or malabsorption syndrome; caution
recommended in patients with impaired renal function, kidney stones,
arteriosclerosis, or heart disease.
- Calcitriol (vitamin D analogue)—initially
0.25 micrograms q am; increase by 0.25 micrograms q 2 to 4 weeks up to 2 mcg;
usual maintenance between 0.5 and 2.0 micrograms per day.
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Complementary and Alternative
Therapies |
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As discussed earlier, nutritional supplementation of calcium and vitamin D is
the mainstay of treatment for hypoparathyroidism. Other dietary guidelines may
also be of value to maximize the intake and balance of micronutients. Finally,
herbs affecting the HPA (hypothalamic-pituitary-adrenocortical) axis are thought
to be of clinical value in restoring normal endocrine
balance. |
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Nutrition |
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See section entitled Drug Therapies for information regarding
appropriate dosing of calcium and vitamin D. Foods rich in calcium include:
- Almonds
- Legumes
- Dark leafy greens
- Blackstrap molasses
- Oats
- Sardines
- Tahini
- Prunes
- Apricots
- Sea vegetables
Calcium and vitamin D are thought to be best absorbed in an acidic
environment; lemon juice, for example, may be added to greens to facilitate
calcium absorption. Other dietary recommendations made by some naturopaths are
as follows:
- Avoidance of foods high in phosphorus because of potential
interference with calcium absorption; these include dairy and carbonated
beverages
- Elimination of caffeine which may increase calcium
excretion
The following supplements have been used clinically for the purposes
indicated and, therefore, may be valuable adjuncts in the case of
hypoparathyroidism:
- Calcium if dietary intake is inadequate
- Magnesium – as stated in the section entitled
Etiology, magnesium deficiency inhibits the secretion and activity of
PTH; in addition, supplementation aids absorption of calcium
- Boron enhances the absorption of calcium
- Vitamin K, produced by intestinal bacteria or obtained through diet
(e.g. dark leafy greens), is important for cellular uptake of calcium
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Herbs |
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Mineral-rich herbs are used in traditional preparations to support normal
bone growth; examples include:
- Horsetail (Equisetum avense)
- Oat straw (Avena sativa)
Although not studied for hypoparathyroidism specifically, amphoteric herbs
believed to act on the HPA axis and used clinically to help normalize endocrine
function include:
- Siberian ginseng (Eleutherococcus senticosus)
- American ginseng (Panax quinquefolium)
- Asian ginseng (Panax ginseng)
- Schizandra (Schizandra chinensis)
- Codonopsis (Codonopsis pilosula).
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Homeopathy |
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Although the usefulness of this modality in the treatment of
hypoparathyroidism has not been explored in clinical trials, the following
remedies have been used clinically to correct dysfunctional calcium metabolism:
- Calcarea carbonica
- Calcarea
phosphorica
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Patient Monitoring |
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Patients usually require frequent follow up and lifelong monitoring,
primarily for acute, life-threatening attacks or hypoparathyroid tetany. Cardiac
monitoring and serial ECGs taken in hospital until stabilization; ECGs should be
done periodically as outpatient as well (q 6 to 12
months). |
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Other
Considerations |
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Prevention |
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Acquired hypoparathyroidism has decreased in incidence with the recognition
of the need to preserve parathyroid glands during surgery and with new
nonsurgical treatments for hyperparathyroidism. No preventive measures are
available for congenital hypoparathyroidism. |
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Complications/Sequelae |
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- Acute tetany leading to respiratory obstruction and a
tracheostomy
- Cataracts
- Stunted growth, teeth malformations, and mental retardation when
condition begins in childhood
- Neuromuscular symptoms
- Parkinsonian symptoms
- Hypothyroidism
- Basal ganglia calcifications
- Ossification of paravertebral ligaments
- Addison's disease
- Pernicious anemia
- Kidney stones if care is not taken to lessen hypercalciuria with
treatment
- Seizures from low calcium
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Prognosis |
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The outcome is fair to good, especially when the diagnosis is made early.
Dental changes, cataracts, and brain calcifications are
irreversible. |
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Pregnancy |
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Excess ionized calcium in pregnant women with overactive parathyroid glands
and high calcium levels can lead to suppression parathyroid gland function in
the fetus and temporary parathyroid gland dysfunction. Calcium gluconate
treatment during pregnancy should be used
cautiously. |
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References |
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Berkow R, Fletcher AJ, Beers MH, eds. The Merck Manual. Rahway, NJ:
Merck & Co. Inc; 1992:1005-1007.
Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic
Guide to Herbal Medicines. Boston, Mass: Integrative Medicine
Communications; 1998:216.
Fauci AS, Braunwald E, Isselbacher KJ, et al., eds. Harrison's Principles
of Internal Medicine. 14th ed. New York, NY: McGraw-Hill Book Co; 1998.
Gupta CMM. Calcium imbalance in hypoparathyroidism. JAPIJ Assoc Physicians
India. 1991;39(8):616-618.
Han YH. Hypoparathyroidism. Medical College of Wisconsin. Accessed at
www.chorus.rad.mcw.edu/doc/00931.html on August 30, 2000.
Reber PM, Heath H III. Hypocalcemic emergencies. Medical Clin North
Am. 1995;79(1):93-106.
Wang NE. Hypoparathyroidism. In: Cunha BA, Geibel J, Griffing GT, et al.,
eds. Medicine, Ob/Gyn, Psychiatry, and Surgery: An On-line Medical
Reference. Accessed at
www.emedicine.com/cgi-bin/foxweb.exe/showsection@d:/em/ga?book=med&sct=ENDOCRINOLOGY
on August 30, 2000.
Werbach M. Nutritional Influences on Illness. New Canaan, Conn: Keats
Publishing; 1988:331-340.
Wheeless CR. Hypoparathyroidism. In: Wheeless CR, ed. Wheeless' Textbook
of Orthopaedics. Accessed at www.medmedia.com/05/310.htm on January 12,
2000. |
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Copyright © 2000 Integrative Medicine
Communications This publication contains
information relating to general principles
of medical care that should not in any event be construed as specific
instructions for individual patients. The publisher does not accept any
responsibility for the accuracy of the information or the consequences arising
from the application, use, or misuse of any of the information contained herein,
including any injury and/or damage to any person or property as a matter of
product liability, negligence, or otherwise. No warranty, expressed or implied,
is made in regard to the contents of this material. No claims or endorsements
are made for any drugs or compounds currently marketed or in investigative use.
The reader is advised to check product information (including package inserts)
for changes and new information regarding dosage, precautions, warnings,
interactions, and contraindications before administering any drug, herb, or
supplement discussed herein. | |