Primary Hyperparathyroidism Symptoms, Causes & Treatment: Melbourne Expert Insights
Primary hyperparathyroidism is a condition in which one or more of the parathyroid glands produce excessive parathyroid hormone (PTH), resulting in elevated calcium levels in the blood. It is most commonly caused by a benign enlargement or tumour (parathyroid adenoma) of one of the glands. While some people have no symptoms, others may experience fatigue, kidney stones, osteoporosis, muscle weakness, memory difficulties, or mood changes. The diagnosis is made with blood tests demonstrating elevated calcium together with an elevated or inappropriately normal PTH level. Parathyroid surgery is the only definitive cure for primary hyperparathyroidism. As an experienced parathyroid surgeon in Melbourne, I manage the full spectrum of this condition and offer minimally invasive parathyroid surgery whenever appropriate. Using high-resolution surgeon-performed ultrasound in the clinic, I can often accurately localise the abnormal gland before surgery, allowing a more targeted operation with a faster recovery.
Table of Contents
What are parathyroid glands?
The parathyroid glands are very small bean-shaped glands that are located behind the thyroid gland. There are generally four glands, two behind each thyroid lobe. The glands are normally the size of a grain of rice, tan-coloured, and weigh about 30-40 mg each.
What is the function of parathyroid glands?
Although the parathyroid glands neighbour the thyroid gland, their function is totally separate. The parathyroid glands are responsible to control blood calcium (Ca) level very tightly. They do this by secreting parathyroid hormone (PTH) which is itself controlled by a feedback mechanism through calcium sensors on the surface of parathyroid cells located in the gland. The Ca level is kept within a narrow normal range (2.1 to 2.6 millimoles per litre). When the Ca level goes down, the parathyroid glands secrete more PTH which quickly brings the Ca level back up by acting on three body organs:
Bone: PTH causes release of calcium from bone into the blood stream.
Bowel: PTH increases calcium absorption in the bowel
Kidney: PTH increases calcium resorption in the kidneys.
On the other hand, when the Ca level goes up, PTH secretion is suppressed which quickly brings the Ca level back to normal.
Why is blood Calcium level so tightly regulated?
Calcium ions play pivotal role in many of the human body’s physiological processes across all organs. Changes in blood calcium level will affect muscle contraction, signal transmission withing the nervous system and the heart, enzymatic metabolic activities, blood clotting, and intracellular signalling leading to changes in cellular secretions and proliferations. Therefor you can see how changes in Ca levels can affect function of many body organs. For example, a low Ca level (hypocalcaemia) causes agitation at a cellular level which can manifest as pins and needles, muscle cramps and spasms, irregularities in heart rhythms, and seizure.
What is primary hyperparathyroidism?
So if the parathyroid glands are functioning normally, a high Ca level should lead to immediate suppression of PTH secretion. When both Ca and PTH level are elevated, it means that one or more of the parathyroid glands have become hyperactive and have not responded to the elevated Ca level by suppressing their PTH secretion. This is called primary hyperparathyroidism (PHP).
The most common underlying pathology is a single parathyroid adenoma (80-90% of the cases). It means that one of the four glands has enlarged due a benign proliferation and secrets excess PTH that is not responding to the elevated Ca level (hypercalcaemia). Removing this single adenoma by surgery will cure the disease.
In about 10% of the cases the cause is multi-gland hyperplasia. It means that two or more of the glands have increased in size and function and therefore surgery should address all these glands to normalise Ca and PTH. Very rarely (<1% of the cases) PHP is due to parathyroid carcinoma, which is a cancerous proliferation of one of the parathyroid glands. This often manifests with a very large parathyroid tumour associated with very high Ca and PTH levels.
What causes primary hyperparathyroidism?
Most cases of PHP are sporadic, i.e., they just happen by chance like most other abnormal growths in the body. About 5% of cases are related to genetic syndromes. Other causes of PHP include radiation exposure (both external radiation to the head and neck and radioactive iodine for treatment of thyroid disease) and prolonged use of a drug called lithium.
What are the symptoms of primary hyperparathyroidism?
The most common presentation of PHP is in fact asymptomatic with incidental finding of elevated Ca on a blood test done by the GP. This is because the rise in Ca level and the damages done by PHP on the musculoskeletal, renal, nervous, and cardiovascular system is often insidious and therefore patients often fail to notice them till later stages. Many patients who are initially labelled as “asymptomatic” report improved in their energy level, mood, irritability, and body aches and pain following surgery! This was most elegantly showed by Professor Paseika in her research using the questionnaire in Table 1. If you are diagnosed with PHP and you score over 200 on this questionnaire you are likely to be affected by the disorder and therefore notice improved symptoms within a year following your surgery.
| Symptom | Your score (0–100) |
|---|---|
| Do you feel tired? |
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| Do you feel thirsty? |
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| Do you have mood changes? |
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| Do you get joint pains? |
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| Are you always irritable? |
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| Do you feel blue or depressed? |
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| Do you feel weak? |
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| Do you get itchy skin? |
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| Are you becoming forgetful? |
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| Do you have headaches? |
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| Do you get abdominal pains? |
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| Do you get bone pains? |
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| Do you have trouble getting out of a chair? |
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| Total Score |
Set a score between 0 and 100 for each symptom. Totals update automatically.
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Table 1. Paseika Questionnaire. No symptoms = 0. Most severe symptoms = 100. A score over 200 in a patient with the diagnosis of PHP is a predictor of significant improvement of symptoms following parathyroidectomy.
Other presentations of PHP include:
Musculoskeletal system: osteoporosis and osteopenia (thinning of bone) leading to fractures
Urinary system: excessive urination leading to thirst, kidney stones, kidney failure
Gastrointestinal system: constipation, stomach ulcers, pancreatitis, loss of appetite, nausea and vomiting
Cardiovascular: high blood pressure, abnormal heart rhythm, heart block
Nervous system: depression, anxiety, headaches, poor memory, confusion, coma
How is primary hyperparathyroidism treated?
Once the blood test confirms the diagnosis of PHP by showing elevated Ca and PTH level, the next step is to identify the underlying pathology. As pointed out above most cases are caused by a single parathyroid adenoma. Therefore, imaging is done to find out which one of the four glands have gone rebellious.
Three imaging modalities are commonly used for the purpose of localising a parathyroid adenoma. These include ultrasound (US), CT scan, and nuclear medicine (NM) scan. The US scan is also done to assess the thyroid gland, as about 25% of patients with PHP also have abnormalities in their thyroid gland. If two of the scans concordantly point out to a single parathyroid adenoma as the culprit, having surgery to remove the gland gives a 98% chance of curing the disease! The operation is called “minimally invasive parathyroidectomy” which is done through a small 2-3cm neck incision often well hidden in a skin crease.
Medical therapy options can be considered in elderly patients who have mild to moderate elevation of Ca, a single adenoma has not been localised on imaging, and are poor surgical candidates. These options include osteoporosis medications such as bisphosphonates and Denosumab, estrogens, diuretics, and Sensipar. These medications are often administered under the supervision of a endocrinologists and need to be continued life-long.
Frequently Asked Questions
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In most cases, no. Primary hyperparathyroidism is usually caused by a benign overactive parathyroid gland (parathyroid adenoma) that continues to produce excessive parathyroid hormone. Once established, the condition rarely resolves on its own. While some people with mild disease can be monitored for a period of time, surgery remains the only definitive cure.
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It can be. Even if you feel well, persistently elevated calcium levels can gradually damage your bones and kidneys. Untreated primary hyperparathyroidism may lead to osteoporosis, kidney stones, reduced kidney function, fatigue, memory problems, mood changes, and an increased risk of fractures. Early assessment by an endocrine surgeon can help determine whether surgery is recommended.
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Parathyroid surgery is recommended for most patients who have symptoms, kidney stones, osteoporosis, reduced kidney function, significantly elevated calcium levels, or are younger than 50 years of age. Surgery may also be appropriate for many patients who feel "asymptomatic" but have subtle symptoms such as fatigue, poor concentration, or muscle aches that improve after successful surgery.
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Parathyroidectomy is one of the most successful endocrine operations. When performed by an experienced endocrine surgeon and the abnormal gland has been accurately identified, the cure rate is typically greater than 95%, with many specialist centres achieving cure rates above 98%.
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No. Most patients undergo a minimally invasive parathyroidectomy through a small incision in the lower neck. The operation usually takes around one hour, and patients usually go home the next day. Recovery is generally quick, with most people returning to normal activities within a few days.
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After blood tests confirm primary hyperparathyroidism, imaging studies are performed to locate the abnormal gland. These commonly include a neck ultrasound and a sestamibi scan. In some patients, a specialised 4D CT scan or PET scan may also be required. These scans help guide surgery but do not establish the diagnosis, which is based on the blood tests.
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Yes. In the vast majority of patients, calcium and parathyroid hormone levels return to normal immediately after successful surgery. Your surgeon will monitor your calcium levels after the operation, as some patients may require temporary calcium supplementation while the remaining normal glands recover.
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Recurrence is uncommon after successful surgery but can occasionally occur, particularly in patients with multiple enlarged glands or inherited conditions. Long-term follow-up with your GP, including occasional calcium blood tests, is usually all that is required.
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Most cases occur by chance and are not inherited. However, around 5% of patients have an underlying genetic condition, such as Multiple Endocrine Neoplasia (MEN) syndrome. If you develop primary hyperparathyroidism at a young age, have multiple abnormal glands, or have a strong family history of endocrine tumours, genetic testing may be recommended.
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Usually not. Restricting calcium in your diet is generally not recommended because your body still requires calcium to maintain healthy bones. Instead, staying well hydrated and maintaining an appropriate dietary calcium intake is advised. Your doctor may also recommend vitamin D replacement if your levels are low.
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Yes. Many patients experience symptoms such as tiredness, poor concentration, memory difficulties, low mood, irritability, or anxiety. These symptoms can develop gradually and are often attributed to ageing or stress. Many patients notice a significant improvement in their energy levels and overall wellbeing after successful parathyroid surgery.
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This is a common situation. The diagnosis is made using blood tests, not imaging. Occasionally, imaging fails to identify the abnormal gland, particularly if it is very small or located in an unusual position. An ultrasound performed by an experienced endocrine surgeon frequently can identify a parathyroid adenoma not seen by radiologists.