What is hypoparathyroidism?
Hypoparathyroidism is a rare condition in which the parathyroid glands, small glands in the back of the neck, are dysfunctional, leading to imbalances of calcium and phosphorus. It is primarily acquired after undergoing neck or throat surgery due to damage or removal of the glands. This can lead to complications that can leave lasting damage, and so treatment for hypoparathyroidism is priority.
What are the parathyroid glands?
The parathyroid glands are located near the thyroid in the throat. They produce the parathyroid hormone, which regulates the levels of both calcium and phosphorus in the blood. With hypoparathyroidism, there is too much phosphorus and not enough calcium in the blood.
How does hypoparathyroidism develop?
In three out of four cases, hypoparathyroidism develops due to a complication after neck surgery. Patients may undergo neck surgery to treat throat or thyroid cancer, vocal nodes, an inflamed oesophagus, or a variety of thyroid issues, for example. During the surgery, the parathyroids may become damaged or need to be removed, which means that there is insufficient production of the parathyroid hormone.
There are several types of non-surgical hypoparathyroidism, though it is less common. They can be categorised as:
- Genetic hypoparathyroidism: emerges during the first years of life, and likely following a family history of the condition. Can be a symptom of other conditions or manifest as a result of a genetic mutation.
- Autoimmune hypoparathyroidism: the immune system attacks the parathyroid glands, stopping them from producing the parathyroid hormone.
- Idiopathic hypoparathyroidism: hypoparathyroidism with an unknown origin, possibly due to insufficient testing. Pseudohypoparathyroidism is one such type, where the parathyroid glands function as normal, but the body does not respond to the parathyroid hormone.
- Paediatric hypoparathyroidism: may arise due to neck injury as an infant, rather than as a result of neck surgery. Children with this condition may be beset with seizures and delayed tooth growth.
- Radiation hypoparathyroidism: radiation exposure to the neck and head can damage or destroy the parathyroid glands.
- Hypoparathyroidism may also develop due to low levels of magnesium in the blood, which is what the parathyroid glands need to make the hormone.
What are the symptoms of hypoparathyroidism?
A lack of calcium in the blood can have far-reaching effects on the body, such as:
- Kidneys: kidney stones, chronic kidney disease, and calcium deposits in the kidney (nephrocalcinosis)
- Nervous system: cramping, twitching, and numbness or tingling (paraesthesia)
- Cognition: ‘brain fog’, memory issues, attention and learning deficits, issues with information processing and problem solving, altered mood
- Brain: seizures, calcium deposits in the brain (brain stones), involuntary movement (Parkinsonism)
- Heart: arrhythmia and hypocalcaemia-associated dilated cardiomyopathy
- Respiratory system: spasms of the lungs and vocal cords, which can impair breathing
- Eyes: cataracts, optic swelling (papilledema)
- Teeth and bones: improperly grown teeth, hardening and changes of shape in bones
How is hypoparathyroidism diagnosed?
There is no one specialised test for diagnosing hypoparathyroidism. Patients struggling with the symptoms may undergo a physical examination followed by blood and urine testing.
With a physical exam, doctors will be checking for the following signs:
- Chvostek's sign, in which tapping the front of the ear triggers facial twitching, a sign that calcium may be low.
- Carpopedal spasm, in which painful muscle spasms in the feet and hands are triggered when inflating a blood pressure cuff.
- Cataracts
- Reflexes that are hyperactive when stimulated with the tendon hammer.
Calcium blood testing is the primary method for diagnosing hypoparathyroidism, the key indications being:
- Low blood calcium
- High blood phosphate
- Low parathyroid hormone levels
To rule out other possible conditions, the doctor may order additional blood testing like bone profiling, vitamin D levels, and thyroid, kidney, or liver function tests.
Urine testing takes over the course of 24 hours, so that multiple samples can be collected and analysed.
Additional testing to assess the extent of the condition can include bone density tests (DEXA scan), genetic testing, autoimmune testing, electrocardiograms, and X-rays to look for shortened bones,
How is hypoparathyroidism treated?
Treatment focuses primarily on reestablishing healthy, if not normal, levels of calcium and phosphorus, which should ease some symptoms. This can include:
- Daily oral supplements of calcium. A long-term level of 2.00mmol/L to 2.25mmol/L is ideal to protect the kidneys and avoid hypoalcaemia
- Prescription vitamin D, which helps the body with calcium absorption, while also removing excess phosphorus
- Magnesium, which can help the parathyroid glands function
- Thiazide diuretics, which will help minimise the loss of calcium during urination
- Parathyroid hormone replacement, which is an emerging approach to treatment.
Patients should implement a diet that is rich in calcium, whilst being low in phosphorus. This can look like a lot of dairy products and leafy green vegetables, whilst cutting down on processed foods, carbonated soft drinks, hard cheeses, nuts, and whole grains.
Who treats hypoparathyroidism?
Endocrinologists are equipped to investigate and treat hypoparathyroidism.
