Experiencing unexplained symptoms like tingling in your fingertips and around your mouth, painful muscle cramps in your hands and feet, or overwhelming fatigue can be a confusing and frightening journey. These are often the first signs of a low calcium level in the blood, which can be caused by a rare endocrine disorder known as hypoparathyroidism. This condition occurs when the body’s tiny parathyroid glands fail to produce enough Parathyroid Hormone (PTH), the master regulator of calcium in the body. While the symptoms can be alarming and severe hypocalcemia is a medical emergency, it is crucial to understand that hypoparathyroidism is a highly manageable, lifelong condition. With a proper diagnosis and consistent daily treatment to replace the effects of the missing hormone, individuals can control their symptoms and lead full, active lives.

Hypoparathyroidism is a rare disorder in which the parathyroid glands, four tiny, rice-sized glands located in the neck behind the thyroid gland, do not produce a sufficient amount of Parathyroid Hormone (PTH). This deficiency of PTH leads directly to low levels of calcium in the blood (hypocalcemia) and high levels of phosphorus (hyperphosphatemia), which causes the majority of the symptoms associated with the disease.

To understand hypoparathyroidism, it is essential to appreciate the central role of PTH in the body’s exquisite control of blood calcium levels. Calcium is not only vital for strong bones, but it is also critical for the normal function of our nerves and muscles.

A helpful analogy is to think of the calcium level in your blood as the water level in a swimming pool that must be kept perfectly full at all times.

• Your four parathyroid glands act as the pool’s highly sensitive, automatic water-level sensor.
• The hormone PTH is the powerful signal this sensor sends to “open the taps” if the water level drops even slightly.
• When the sensor detects low calcium, it immediately releases PTH, which signals the body to do three things simultaneously:
  • It opens a tap from a large reserve tank (the bones), causing them to release calcium into the blood.
  • It prevents water from being drained out by telling the kidneys to stop excreting calcium in the urine.
  • It turns on a hose to draw in more water from an outside source by activating vitamin D in the kidneys, which is necessary to absorb calcium from the food you eat in your intestines.
• In hypoparathyroidism, this automatic sensor is broken or has been removed. It can no longer detect a drop in the water level or send out the PTH signal to open the taps. As a result, the pool’s water level (your blood calcium) can drop to dangerously low levels, leading to severe neuromuscular problems.

In my experience, patients often arrive with muscle cramps or tingling, unaware that these symptoms are tied to a hormonal issue rather than a neurological one.

The direct cause of hypoparathyroidism is any condition that leads to the damage, destruction, or congenital absence of the parathyroid glands, resulting in insufficient production of PTH.

Post-Surgical Hypoparathyroidism

This is, by far, the most common cause of hypoparathyroidism.

• The parathyroid glands are very small and are located very close to the thyroid gland. During surgery on the thyroid gland (a thyroidectomy) or on the parathyroid glands themselves (for a condition called hyperparathyroidism), the glands can be accidentally removed or their delicate blood supply can be permanently damaged.
• This is a known, unavoidable risk of necessary neck surgery. In many cases, the hypoparathyroidism that occurs after surgery is temporary, but if all four glands are damaged, it can be permanent.

Autoimmune Disease

In this form, the body’s own immune system mistakenly recognizes the parathyroid glands as foreign and produces autoantibodies that attack and destroy the glands. This can occur as an isolated condition or as part of a broader autoimmune syndrome.

Genetic or Congenital Causes

These are rare causes where a person is born with the condition.

• DiGeorge Syndrome (22q11.2 Deletion Syndrome): This is a genetic syndrome where children are born with several developmental problems, including the failure of the parathyroid glands to form properly.
• Other Rare Genetic Mutations: A person can be born with a specific mutation in a gene that is essential for parathyroid gland development or for the production of the PTH hormone.

Other Rare Causes

• Radiation Damage: Extensive radiation therapy to the neck for cancer can damage the parathyroid glands.
• Infiltrative Diseases: The glands can be damaged by the abnormal deposition of minerals, such as in hemochromatosis (iron overload) or Wilson disease (copper overload).
• Severe Magnesium Deficiency: Very low levels of magnesium in the body can impair the ability of the parathyroid glands to release PTH.

Clinically, I most frequently encounter it as a complication following thyroid or parathyroid surgery where the glands are accidentally damaged or removed.

A person develops hypoparathyroidism either as a complication of necessary neck surgery or as a result of an underlying autoimmune or genetic condition. It is not contagious. Except for the rare familial genetic forms, it is not a condition that is typically passed down from a parent to a child. The most common cause, post-surgical damage is an acquired condition.

Clinically, inherited forms like DiGeorge syndrome or autoimmune polyendocrine syndrome can lead to hypoparathyroidism early in life, though they’re less common.

The signs and symptoms of hypoparathyroidism are not caused by the low level of PTH itself. They are all a direct result of the low level of calcium in the blood (hypocalcemia). A low calcium level makes the nerves and muscles abnormally irritable and prone to spontaneous firing.

Symptoms can range from mild and intermittent to severe and life-threatening. The hallmark symptoms are neuromuscular.

• Paresthesias: This is often the first symptom. It is a sensation of tingling, numbness, or “pins-and-needles,” typically felt around the mouth, in the fingertips, and in the toes.
• Muscle Cramps and Spasms (Tetany): As the calcium level drops further, painful muscle cramps and spasms can occur. A characteristic sign is carpopedal spasm, where the hands and feet cramp into a contorted, flexed position.
• Muscle Twitching.
• Fatigue and Weakness.
• “Brain Fog”: Difficulty concentrating, confusion, and memory problems.
• Mood Changes: Anxiety, irritability, and depression are common.
• Chronic Symptoms: Over the long term, untreated hypoparathyroidism can lead to dry, coarse hair, brittle nails, and dry, scaly skin. Dental abnormalities can also occur if the condition is present during childhood.

Symptoms of a Hypocalcemic Crisis

A sudden and severe drop in blood calcium can trigger a life-threatening emergency that requires immediate medical care. These signs include:

• Severe Tetany: Widespread, painful muscle spasms affecting the entire body.
• Laryngospasm: A spasm of the muscles of the voice box (larynx), which can cause a high-pitched sound when breathing in (stridor) and can obstruct the airway, leading to suffocation.
• Seizures.
• Cardiac Arrhythmias: Abnormal heart rhythms and, in severe cases, heart failure.

Clinically, I look for classic signs like Chvostek’s or Trousseau’s sign, especially those presenting with unexplained hypocalcemia or carpopedal spasms.

A diagnosis of hypoparathyroidism is often suspected in a patient who develops the characteristic symptoms of hypocalcemia, particularly if they have recently undergone neck surgery. The diagnosis is confirmed with a simple panel of blood tests.
The diagnostic process, usually managed by an endocrinologist, involves:

1. A Detailed Medical History: The doctor will ask about your symptoms and, crucially, about any history of thyroid or other neck surgery.
2. Blood Tests: The diagnosis is made by looking at the results of three key blood tests, drawn at the same time. The classic pattern that confirms a diagnosis of primary hypoparathyroidism is:
   • Low Serum Calcium.
   • High Serum Phosphorus (because PTH is needed to help the kidneys excrete phosphorus).
   • An inappropriately low or undetectable PTH level. This is the key finding. In a healthy person, a low calcium level would trigger a very high PTH level as the body tries to compensate. A low PTH level in the face of a low calcium level proves that the parathyroid glands have failed.
3. Other Tests: A blood test for magnesium is also important. An electrocardiogram (ECG) will be performed to check for the effects of low calcium on the heart’s electrical rhythm.

In my experience, differentiating it from pseudohypoparathyroidism is key. Measuring PTH alongside calcium and phosphate levels helps distinguish the two.

Hypoparathyroidism is a chronic condition requiring lifelong treatment. The goal of treatment is to relieve the symptoms of hypocalcemia and to maintain the blood calcium level in a stable, low-normal range.

1. Conventional Therapy: Calcium and Vitamin D

The cornerstone of management is replacing the end-products that are missing due to the lack of PTH.

• High-Dose Calcium Supplements: Patients need to take calcium supplements several times a day to maintain their blood calcium levels.
• Activated Vitamin D: This is a crucial part of the therapy. Normal vitamin D from supplements or sunlight must be “activated” by an enzyme in the kidneys, and this activation process is controlled by PTH. Since PTH is missing, a person with hypoparathyroidism cannot activate their own vitamin D. Therefore, they must take a prescription for an already-activated form of vitamin D, most commonly calcitriol. This allows them to absorb calcium from the food they eat.

The goal of this therapy is to keep the blood calcium level just high enough to prevent symptoms of hypocalcemia, but not so high that it causes excess calcium to be spilled into the urine, which can lead to kidney stones and kidney damage over the long term. This requires regular blood and urine monitoring to fine-tune the doses.

2. PTH Replacement Therapy

In recent years, a synthetic form of parathyroid hormone, teriparatide or abaloparatide, has been approved for the treatment of hypoparathyroidism that cannot be well-controlled with conventional therapy. It is given as a daily injection and can help to stabilize calcium levels and reduce the need for large doses of calcium and calcitriol supplements.

3. Emergency Treatment for Severe Hypocalcemia

An acute, symptomatic drop in calcium is a medical emergency that requires hospitalization. The treatment is an intravenous (IV) infusion of calcium gluconate to rapidly and safely restore the blood calcium level to a safe range.

Clinically, I’ve found that maintaining stable calcium levels without causing hypercalciuria requires careful, individualized dosing and regular monitoring.

Hypoparathyroidism is a rare endocrine disorder in which the body fails to produce enough parathyroid hormone, leading to low blood calcium and a host of debilitating neuromuscular symptoms. Most often occurring as a complication of necessary neck surgery, the condition requires lifelong management. While the diagnosis can be frightening, it is important to remember that it is a highly manageable condition. Through a diligent, daily commitment to taking calcium and activated vitamin D supplements, and by working in a close partnership with an endocrinologist to monitor and fine-tune treatment, individuals with hypoparathyroidism can effectively control their symptoms, prevent dangerous complications, and lead full, healthy, and productive lives.

1. The National Organization for Rare Disorders (NORD). (2023). Hypoparathyroidism. Retrieved from https://rarediseases.org/rare-diseases/hypoparathyroidism/
2. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). (2019). Hypoparathyroidism. Retrieved from https://www.niddk.nih.gov/health-information/endocrine-diseases/hypoparathyroidism
3. The HypoPARAthyroidism Association, Inc. (n.d.). About Hypoparathyroidism. Retrieved from https://hypopara.org/