An Overview of Hypoparathyroidism

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Hypoparathyroidism is a rare condition characterized by the diminished function or absence of parathyroid hormone (PTH). PTH works with your kidneys and bones to maintain the balance of calcium and phosphorous in your body. A deficiency in PTH can result in low levels of calcium (hypocalcemia) and high levels phosphorous, which leads to a variety of problems most commonly involving the muscles, nerve endings, bones, and skin.

PTH is produced by the parathyroid glands—four small endocrine glands located next to the thyroid gland. Hypoparathyroidism can occur if the parathyroid glands don't function optimally, if they are missing, or if the kidneys or bones do not respond to PTH as they should.

Symptoms

Signs and symptoms of hypoparathyroidism are most often related to low calcium levels. In severe situations, the elevated phosphorus levels can have some effects as well.

Common effects of hypoparathyroidism include:

  • Hair that is dry or breaks easily, hair loss
  • Brittle nails, ridges in nails
  • Dry, coarse, or thick skin
  • Fatigue
  • Depression
  • Anxiety
  • Headaches
  • Tingling in fingers/toes/lips (paresthesias)
  • Muscle twitches
  • Muscle cramps or pain
  • Impaired formation of the teeth
  • Kidney stones

Severe effects of hypoparathyroidism, which are less common, include:

  • Cataracts
  • Calcium deposits in the organs of the body, particularly the kidneys
  • Heartbeat irregularities (Arrhythmias)
  • Weakness of the respiratory muscles and trouble breathing
  • Seizures
  • Laryngospasm (closing off of the upper airway)
  • Heart failure

Less common effects of hypoparathyroidism that specifically result from high phosphorus levels include:

  • Constipation
  • Nausea
  • Diarrhea
  • Itching
  • Red eyes
  • Possible increased risk of cancer

The most important effect of hyperphosphatemia (high phosphorus levels) is actually low calcium, which results from the complex interactions between calcium, phosphorus, bones, kidneys, and PTH.

Causes

Hypoparathyroidism has a number of causes, the nature of which help classify the disease.

Primary hypoparathyroidism is disease of the parathyroid glands, while secondary hypoparathyroidism results from damage to the glands.

Sometimes there is no identifiable cause, and the condition may be categorized as idiopathic hypoparathyroidism.

Causes of primary hypoparathyroidism include:

  • Being born with malfunctioning, malformed, or missing parathyroid glands (congenital hypoparathyroidism)
  • Being born to a mother who has excess PTH or high calcium levels during pregnancy, which can cause a baby to develop temporary or long-term hypoparathyroidism
  • Genetic conditions that may result in inadequate development and function of the parathyroid glands, such as DiGeorge syndrome and familial isolated hypoparathyroidism
  • Antibodies that attack parathyroid tissue, preventing the glands from producing PTH (as is the case with autoimmune hypoparathyroidism)

Causes of secondary hypoparathyroidism:

  • Traumatic injury of the head or neck that impairs gland function
  • Surgical injury to the parathyroid glands or to their blood supply, such as can occur after thyroid surgery for thyroid cancer, goiter, nodules, or hyperthyroidism. (Post-surgical hypoparathyroidism may resolve over time.)
  • Radiation treatment for head/neck cancers, which can damage to the parathyroid glands
  • Invasion of thyroid cancer or metastatic cancer from elsewhere in the body
  • Hemochromatosis and thalassemia, which can result in iron buildup throughout the body, including the parathyroid glands, with resulting dysfunction
  • Wilson disease, a genetic condition that can cause excess copper levels
  • Extremely low levels of magnesium, which is needed for PTH to be secreted by the parathyroid glands

You can generally make enough PTH if you have only one or a portion of a parathyroid gland. However, damage to the whole region can cause symptoms.

Diagnosis

The evaluation of the symptoms of hypoparathyroidism usually begins with a laboratory test that measures levels of electrolytes in the blood, including calcium and phosphorus. The combination of low calcium levels and high phosphorus levels generally triggers further testing of PTH levels to verify hypoparathyroidism.

Reference Ranges

  • Calcium levels: Normal range 8.5 to 10.5 mg/dL
  • Phosphorus levels: Normal range 2.5 to 4.5 mg/dL
  • PTH levels: Normal range 10 to 65 ng/L

If you have had thyroid surgery, radiation, or neck trauma, the potential for developing hypoparathyroidism may have been already anticipated as a possible complication of your condition. However, in children or in adults who have no history of damage to the neck, tests may be performed to evaluate the cause of hypoparathyroidism.

Tests for evaluation of hypoparathyroidism include:

  • Blood tests: Additional electrolyte levels that may not have been already checked, including magnesium, iron, and copper, may be evaluated to search for the cause of hypoparathyroidism as well as associated electrolyte abnormalities.
  • Urine test: The concentration of electrolytes in your urine is measured when you have abnormal levels in your blood. This helps your doctor determine whether you are losing calcium and phosphorus in the urine or whether you have a low level in general.
  • Imaging tests: A neck computed tomography (CT) scan or magnetic resonance imaging (MRI) can identify tumors or other structural abnormalities near the parathyroid glands.
  • Genetic and metabolic tests: Your doctor may search for causes of hypoparathyroidism such as Kearns-Sayre syndrome or MELAS syndrome based on your other signs and symptoms, as these disorders are associated with other problems in addition to hypoparathyroidism.

Effects of hypoparathyroidism also need to be assessed and followed to determine the right course of treatment.

Treatment

Treatment for hypoparathyroidism includes supplemental calcium and vitamin D, taken in oral form. Vitamin D helps the body absorb calcium and eliminate excess phosphorous, so it acts similarly to PTH and can help compensate for the hormone deficiency.

Sun exposure is an important way to raise your vitamin D levels, even if you are taking vitamin D supplements. The recommended amount is 10 to 15 minutes of direct sunlight at least twice a week. Do not spend excessive time in the sun, as this may increase your risk of skin cancer.

Calcium supplementation is taken as calcium carbonate or calcium citrate, with each dose not exceeding 500 mg for a maximum of 2000 mg daily. Vitamin D is taken as Calcitriol (1,25-dihydroxyvitamin D), which comes in tablets of 0.25 or 0.5 mcg or as an oral solution.

These medication doses are adjusted based on your calcium and phosphorus levels, and generally must be taken several times per day to prevent excessive fluctuations in your blood level. When taking these supplements, your calcium and phosphorus levels will be periodically monitored to ensure they are in the normal range.

If your calcium level becomes drastically low, you may need to have intravenous (IV) calcium to quickly get it into your bloodstream to prevent serious complications.

If your levels and symptoms are not relieved by calcium and vitamin D, you may be prescribed recombinant PTH. This medication is typically delivered via twice-a-day injections or through a pump mechanism, which is similar to an insulin pump.

Diet and Lifestyle

Eating a diet rich in calcium and low in phosphorous is important if you have hypoparathyroidism, even if you are being treated with vitamin D or recombinant PTH.

Calcium-rich foods include:

  • Almonds
  • Apricots
  • Beans
  • Cod liver oil
  • Dairy products
  • Dark green leafy vegetables (spinach/kale/broccoli)
  • Fish (oysters/salmon)
  • Fortified breakfast cereals
  • Fortified orange juice
  • Mushrooms
  • Oats
  • Prunes
Calcium Requirements and Dietary Sources

Your doctor may recommend that you avoid these phosphorus-rich foods:

  • Coffee
  • Eggs
  • Lunch meats
  • Red meat
  • Refined foods (white bread, pasta)
  • Sausage
  • Soft drinks
  • Trans fats (found in foods such as baked goods made with shortening, snacks, fried foods, creamers, and margarine)

A Word From Verywell

Hypoparathyroidism is a rare condition that is often part of a syndrome characterized by multiple systemic problems. If you or your child has hypoparathyroidism, there are a number of effects, and you will have to be very attentive to the treatment in order to prevent complications. With proper treatment, however, the condition can be well controlled.

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Article Sources
  • Mannstadt M, Bilezikian JP, Thakker RV, et al. Hypoparathyroidism. Nat Rev Dis Primers. 2017 Aug 31;3:17055. doi: 10.1038/nrdp.2017.55.

  •  Triantafyllou E, Yavropoulou MP, Anastasilakis AD, Makras P. Hypoparathyroidism: is it that easy to treat? Hormones (Athens). 2018 Jun 6. doi: 10.1007/s42000-018-0032-6. [Epub ahead of print]