What is Hypoparathyroidism?
Under normal situations, the amount of calcium in the body’s outside fluid is controlled within a specific limit. Maintaining the right level of calcium in the body involves a complex network of hormones like parathyroid hormone (PTH), different substances made by vitamin D, and calcitonin, that all together manage calcium in the bones, kidneys, and gut.
Hypoparathyroidism is a rare hormonal disorder where the parathyroid glands don’t work properly, leading to a deficiency in the parathyroid hormone. This deficiency causes low calcium levels, high phosphate levels, and increased muscle sensitivity in the body. Patients with hypoparathyroidism often show symptoms related to low calcium levels such as muscle pain, spasms, twitching, new-onset seizures, and in extreme cases, continuous muscle contraction.
The severity of these symptoms can vary depending on how low the body’s calcium level is and how long the parathyroid glands have not been working properly. Other symptoms related to the heart, such as sudden heart muscle disease and congestive heart failure (a condition where the heart can’t pump enough blood to meet the body’s needs) can also occur due to the lack of calcium.
The most common cause of hypoparathyroidism is accidental removal or injury during head and neck surgeries. However, there are other causes as well.
Doctors typically diagnose hypoparathyroidism through laboratory tests that show low calcium levels and a lack or decreased presence of the parathyroid hormone. Also, the test might show high blood phosphorus, low levels of a vitamin D substance in the body, and high levels of calcium being passed in the urine. The treatment for hypoparathyroidism mostly includes increasing levels of calcium, vitamin D, and magnesium in the body through supplements.
In the recent years, a therapy using artificial human parathyroid hormone has been developed and is now available for patients who don’t respond to supplements. Those with hypoparathyroidism may also experience kidney disease and kidney stones, cataracts, cognitive problems, irregular heart rhythms, anxiety, and depression.
What Causes Hypoparathyroidism?
Hypoparathyroidism, or a lack of parathyroid hormone in the body, can happen for many reasons. The most common reason is unintentional damage or removal during surgery in the head or neck area, like removing the thyroid.
There are also several other reasons:
* Certain inherited conditions or genetic mutations such as DiGeorge Syndrome, which affects the body’s development, and autosomal dominant hypocalcemia, which causes low blood calcium levels.
* The body’s own immune system attacks and destroys the parathyroid tissue, as seen in type 1 polyglandular autoimmune syndrome, a disorder that often features multiple hormonal deficiencies.
* Drugs that stimulate the immune system, called immune checkpoint inhibitors.
* Having too much or too little magnesium in your body.
* Conditions that cause other substances to invade and damage the parathyroid tissue, including granulomatous disease (a type of inflammation), hemochromatosis (an iron overload disorder), and metastatic disease (cancer that has spread from where it started).
* Injury to the parathyroid glands caused by radiation treatment.
* Severe illness or burns.
* A condition passed along in families known as maternal familial hypocalciuric hypercalcemia, which can cause high levels of calcium in the mother’s blood.
And in some cases, doctors are unable to find a cause – this is referred to as idiopathic hypoparathyroidism.
Risk Factors and Frequency for Hypoparathyroidism
Hypoparathyroidism is a condition that affects a small portion of the population in the United States, with estimates of its occurrence ranging from 6.4 to 37 for every 100,000 people each year. Most of these cases, about 75%, are a result of complications from thyroidectomy or head and neck surgery. It’s important to note that this complication could be temporary or permanent, and the chances vary depending on the skill level of the surgeon. There are other causes of hypoparathyroidism, but they’re pretty rare. Factors such as the patient’s age when symptoms start, their family medical history, and other related symptoms can often give a clue to the cause of the condition.
Signs and Symptoms of Hypoparathyroidism
Hypoparathyroidism, a condition where the parathyroid glands in your neck don’t produce enough parathyroid hormone, can be evaluated through a detailed medical history and check for symptoms and potential complications. Often, people become aware of this condition following neck surgery, when they notice an immediate onset of symptoms. If you have experienced symptoms of neuromuscular irritability like numbness around the mouth, tingling in hands and feet, muscle cramps, voice box spasms, or seizures, you should consider an assessment for hypoparathyroidism. If you have no symptoms but your routine blood tests show low calcium levels, or if you or your family have a history of autoimmune diseases or neck surgery, you should also be screened for parathyroid hormone deficiency. Notably, a history of severe immune deficiency could point to DiGeorge syndrome, while autoimmune issues like adrenal insufficiency or recurrent yeast infections could indicate polyglandular autoimmune syndrome type 1. Symptoms of hypoparathyroidism could also manifest if you have a history of malnutrition, diabetes, alcohol abuse, severe diarrhea, or use of medications that affect kidney function and lead to magnesium deficiency.
If you develop sudden signs of low calcium following a head or neck procedure, hypoparathyroidism could be suspected. These signs are often traced through a physical examination, where doctors look specifically for Chvostek’s and Trousseau’s signs. Alongside these, you might also present with related conditions as a result of your hypoparathyroidism. The tell-tale signs of hypoparathyroidism during a physical examination include:
- Chvostek sign: This is observed when your upper lip and side of the mouth react with a twitch when a doctor taps on the facial nerve as it comes out of the salivary gland.
- Trousseau sign: This test involves inflating a blood pressure cuff above your systolic blood pressure. The sign is positive if, within 3 minutes, a hand spasm develops where your thumb bends and fingers close together. But this could be painful, and doctors will deflate the cuff once the sign is apparent.
- Ophthalmologic and neurological findings: Cataracts and conditions related to mental health, such as anxiety, depression, bipolar affective disorder, seizures, and tingling sensations, can often be found in patients suffering from long-term hypoparathyroidism.
Testing for Hypoparathyroidism
If your doctor suspects that you might have a condition called hypoparathyroidism, he or she will typically run specific laboratory tests to confirm the diagnosis. This illness is often identified by low levels of calcium and parathyroid hormone (PTH), a hormone that regulates calcium levels in the body. However, before hypoparathyroidism can be diagnosed, your doctor must first rule out a condition named hypomagnesemia, which is a lack of magnesium in the blood.
There are some specific situations when these laboratory tests are especially crucial. Such situations might include when you start showing symptoms immediately after head and neck surgery or if you start experiencing muscle spasms or twitching. Also, if you are not showing any discernible symptoms but blood tests reveal low levels of calcium and you have a history of autoimmune diseases or head and neck surgery, your doctor might want to check for a PTH deficiency.
The diagnosis of hypoparathyroidism is confirmed by finding low levels of calcium and PTH in two separate blood tests taken at least two weeks apart. Other laboratory tests that can support this diagnosis include measures of your albumin levels (a protein which helps in calcium function in the body); levels of phosphorus and calcium in your urine, and monitoring your kidneys’ functionality by checking blood urea nitrogen (BUN), creatinine, and creatinine clearance levels.
After a diagnosis of hypoparathyroidism has been made, your doctor will recommend further studies to establish a reference point for later comparison and to identify any related abnormalities or complications. These could include bone formation measures, vitamin D deficiency, kidney function tests, electrocardiogram (ECG) to check for changes in heart rhythm associated with hypoparathyroidism, or kidney imaging (via a renal ultrasound or computerized tomography-CT) to check for kidney stones or calcium deposits in the kidneys (nephrocalcinosis or nephrolithiasis).
Patients diagnosed with hypoparathyroidism are advised to have these tests every 6 to 12 months. However, if the treatment is not working as expected, testing may need to be done more frequently.
Treatment Options for Hypoparathyroidism
After neck surgeries (such as thyroid removal), some patients may experience hypoparathyroidism, a condition where the body does not produce enough parathyroid hormone (PTH), leading to low calcium levels. To manage this, doctors usually recommend taking oral calcium and calcitriol (a form of vitamin D). Most patients start to improve within a month and the treatment can then be gradually reduced under careful monitoring.
In severe cases, where low calcium levels are causing complications such as heart, lung, or severe neurological problems, an emergency treatment is given. This involves giving a calcium bolus (a large dose of calcium) intravenously (into the vein) over 10 to 20 minutes, with heart monitoring at the same time. Following this, the standard treatment of oral calcium and calcitriol is started.
If hypoparathyroidism becomes a long-term problem, ongoing treatment involves taking calcium and vitamin D supplements to maintain normal calcium levels.
It’s worth noting that the type of calcium supplement matters because different forms contain different amounts of elemental calcium, which is the actual amount of calcium that’s available for your body to use. For instance, calcium carbonate is 40% elemental calcium while calcium gluconate only has 9%.
In the past, some patients with hypoparathyroidism needed very large doses of vitamin D to maintain normal calcium levels. This was because they had abnormal vitamin D metabolism due to their low levels of PTH and high levels of phosphate. However, the current recommendation involves taking calcitriol and calcium supplements.
Patients with hypoparathyroidism need to have regular check-ups to ensure their calcium, phosphorus, and kidney function are all normal and that the supplements they’re taking are not causing other problems such as kidney stones or soft tissue calcifications.
While most patients are successfully treated using calcitriol and calcium, there are other options for those who don’t respond well to these standard therapies. For example, some patients may benefit from treatment with parathyroid hormone replacement, however, this should only be considered in certain circumstances as the long-term effects are still unknown.
What else can Hypoparathyroidism be?
If someone shows signs of hypoparathyroidism, doctors may need to rule out two conditions with similar symptoms:
- Hypomagnesemia (low magnesium levels in the blood)
- Falsely low PTH (parathyroid hormone) due to a problem with the test used to measure it
There’s also a condition called parathyroid hormone resistance, or pseudohypoparathyroidism. This condition causes low calcium levels in the blood just like hypoparathyroidism, but in this case, PTH levels are actually high, not low. Some people with a certain type of pseudohypoparathyroidism, known as Albright hereditary osteodystrophy, show specific characteristics like being short, having a round face, and having shorter than normal fourth fingers. This is caused by a defect in a particular part of the parathyroid hormone receptor, specifically the G-alpha subunit.
What to expect with Hypoparathyroidism
In cases of long-term deficiency of PTH (parathyroid hormone, a hormone that helps control calcium levels in the blood), a lifetime of calcium supplements and calcitriol (a type of Vitamin D) are often required. Most people with this condition can live normal, healthy lives, though some may still have ongoing complaints. These complaints may be improved by substituting the parathyroid hormone that their body is missing.
However, the standard treatment involving calcium and calcitriol also raises the risk of kidney problems. This occurs because these substances, when taken in substantial amounts, can put extra strain on the kidneys, potentially leading to reduced kidney function.
Possible Complications When Diagnosed with Hypoparathyroidism
The most frequent complications from hypoparathyroidism are chronic kidney disease and kidney stones. Other potential issues could include eye problems like cataracts, mental health conditions like anxiety and depression, heartbeat irregularities, and cognitive issues.
Those undergoing treatment with calcium and calcitriol may experience low or high calcium levels in their blood. They also have an increased risk of developing kidney stones and kidney disease. Additionally, these patients might struggle with low quality of life scores. Due to the increased risks of kidney-related complications, it’s important that patients regularly receive abdominal scans to check for kidney stones or other renal conditions. CT scans may be more effective than ultrasounds in diagnosing these conditions, although they do come with a higher exposure to radiation.
Doctors might also choose to check bone density and brain function if there are abnormalities. There’s a type of treatment involving daily injections of a parathyroid hormone substitute, alopegteriparatide, that has been known to stabilize calcium and phosphorus levels in the blood, reduce calcium in the urine, and improve quality of life. However, alopegteriparatide is currently being evaluated by the FDA.
Most common complications:
- Chronic kidney disease
- Kidney stones
- Cataracts
- Score poorly on quality of life scales
- Anxiety and depression
- Heart rhythm problems
- Higher risk of developing kidney stones and kidney insufficiencies with some treatments
- Mental function issues
Preventing Hypoparathyroidism
People suffering from hypoparathyroidism need to understand the importance of regularly taking calcium and calcitriol supplements. Hypoparathyroidism is a condition that causes low levels of parathyroid hormone, which plays a key role in regulating your body’s calcium levels. Calcitriol is a form of vitamin D used to treat and prevent low levels of calcium in the blood.
These individuals also need to regularly get blood tests for calcium, phosphorus, and kidney function. ‘Periodic monitoring’ is a medical term for getting regular check-ups. This is important to ensure the body is reacting well to the supplements and is maintaining the right levels of these substances. The goal of this is to keep their calcium levels within a low-normal range to manage their symptoms and avoid a condition known as hypercalciuria.
Hypercalciuria is a medical condition that involves the release of too much calcium through urine. This condition can increase one’s risk for developing kidney stones. By taking their medications as directed and getting regular check-ups, patients can control their symptoms and avoid potential complications.
