Hypoparathyroidism - home health advice

Overview
Definition

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.
Etiology

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

Risk Factors

* Genetic
* Massive radiation to the thyroid gland
* Drugs
* Surgical resection of parathyroid adenoma
* Parathyroidectomy
* Thyroidectomy

Signs and Symptoms

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

Differential Diagnosis

* Causes of hypocalcemia including pancreatitis or malabsorption
* Causes of hypomagnesemia
* Causes of hyperphosphatemia
* Renal failure
* Pseudohypoparathyroidism
* Vitamin D deficiency

Diagnosis
Physical Examination

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.
Laboratory Tests

* 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

Pathology/Pathophysiology

* 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)

Imaging

* 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

Other Diagnostic Procedures

* 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

Treatment Options
Treatment Strategy

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.

Complementary and Alternative Therapies

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.
Nutrition

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

Herbs

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).

Homeopathy

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?

Patient Monitoring

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).
Other Considerations
Prevention

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.
Complications/Sequelae

* 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

Prognosis

The outcome is fair to good, especially when the diagnosis is made early. Dental changes, cataracts, and brain calcifications are irreversible.
Pregnancy

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.
References

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