Hyperparathyroidism/ Overactive Parathyroid

What is hyperparathyroidism?

Although it may be detected through routine blood tests before symptoms appear, untreated hyperparathyroidism can lead to complications such as osteoporosis, kidney stones, and cardiovascular issues. Early diagnosis and appropriate management are key to preventing long-term harm.

What causes hyperparathyroidism?

The underlying cause of hyperparathyroidism depends on its type, with different mechanisms leading to overproduction of parathyroid hormone (PTH).

• Primary hyperparathyroidism — this is most often caused by a benign parathyroid adenoma, a non-cancerous growth on one of the glands that disrupts normal feedback control of PTH production. Less commonly, it may be due to parathyroid hyperplasia, where all four glands enlarge and become overactive. Certain genetic conditions, such as Multiple Endocrine Neoplasia (MEN) syndromes, can also increase risk.

• Secondary hyperparathyroidism — this develops as a compensatory response to low blood calcium over a prolonged period. This can be due to:

• Chronic kidney disease (CKD) — reduced kidney function impairs vitamin D activation and calcium balance.

• Vitamin D deficiency — insufficient vitamin D reduces calcium absorption from the gut.

• Malabsorption disorders — such as coeliac disease or inflammatory bowel disease, which interfere with nutrient absorption.

• Tertiary hyperparathyroidism — usually arises after long-standing secondary hyperparathyroidism, particularly in patients with advanced CKD. In this case, the parathyroid glands become autonomous, continuing to produce excess PTH even when calcium levels normalise.

• Parathyroid carcinoma — This is a cancerous growth of the parathyroid gland and results in very high, sometimes life-threatening levels of high calcium. Although rare, its diagnosis is crucial. 

Other contributing factors may include prolonged lithium therapy, radiation exposure to the neck, and, in rare cases, familial genetic disorders affecting calcium regulation.

What are the symptoms of hyperparathyroidism?

The symptoms of hyperparathyroidism can vary widely and may develop gradually, which makes the condition difficult to detect in its early stages. Some people have no noticeable symptoms and are diagnosed only through routine blood tests showing high calcium levels. 

When symptoms do occur, they are often related to the effects of prolonged high calcium in the blood (hypercalcaemia) and the imbalance in bone metabolism caused by excess parathyroid hormone (PTH).

Common symptoms include:

• Bone and joint pain — due to calcium being released from bones, increasing the risk of osteoporosis and fractures.

• Kidney stones — high calcium levels can lead to calcium containing stones in the urinary tract.

• Abdominal discomfort — including nausea, vomiting, constipation, or peptic ulcers.

• Excessive thirst and frequent urination — as water is lost trying to excrete the excess calcium in urine.

• Fatigue and muscle weakness — often accompanied by reduced exercise tolerance.

• Mood changes and cognitive difficulties — such as depression, irritability, poor concentration, or memory problems.

In severe or long-standing cases, untreated hyperparathyroidism can cause complications such as brittle bones, recurrent kidney stones, pancreatitis, and cardiovascular problems. Because these symptoms can overlap with other medical conditions, a thorough medical evaluation is essential for accurate diagnosis.

Who is at risk of hyperparathyroidism in Singapore? 

Hyperparathyroidism can affect anyone, but certain groups are more likely to develop the condition. In Singapore, patterns of risk are influenced by age, gender, lifestyle, and existing health conditions.

• Women, especially post-menopausal — primary hyperparathyroidism occurs more often in women than men, with the highest incidence in the 50–60 age range. 

• Individuals with chronic kidney disease or vitamin D deficiency — secondary hyperparathyroidism frequently affects people whose kidneys cannot properly activate vitamin D, as it disrupts calcium balance. Vitamin D deficiency is common due to lifestyle habits and limited sun exposure in the average person who works indoors.

• Those with a family history or history of radiation exposure — genetic syndromes such as multiple endocrine neoplasia (MEN) can increase the likelihood of developing overactive parathyroid glands. Previous radiation to the neck, such as during childhood cancer treatment, is also a known risk factor.

• Users of certain medications such as lithium — long-term lithium therapy, often prescribed for bipolar disorder, can interfere with parathyroid function and raise the risk of developing the condition.

• Older adults — the risk of primary hyperparathyroidism increases with age, and most cases are diagnosed in people over 50.

What complications can arise due to hyperparathyroidism?

If hyperparathyroidism is left untreated, prolonged excess of parathyroid hormone (PTH) and high calcium levels can lead to significant complications affecting multiple organ systems. These arise primarily from excess calcium leaching from bones and calcium deposits forming in other tissues.

Potential complications include:

• Osteoporosis and fractures — continual calcium loss from bones makes them fragile, which can increase the risk of fracture, particularly in the hips, spine, and wrists.

• Kidney stones — high calcium in the urine can crystallise, forming stones that may cause severe pain, urinary tract infections, or kidney damage.

• Chronic kidney disease — repeated stone formation or calcium deposits can impair kidney function over time in a process termed ‘nephrocalcinosis’.

• Cardiovascular issues — long-term hypercalcaemia may contribute to high blood pressure, heart rhythm disturbances, and vascular calcification.

• Pancreatitis — calcium deposits in the pancreas can trigger inflammation, leading to abdominal pain and digestive issues.

• Neurocognitive effects — persistent high calcium can cause ongoing fatigue, depression, poor memory, and difficulty concentrating.

These complications highlight the importance of early diagnosis and management, even in individuals without obvious symptoms, to prevent irreversible damage to bones, kidneys, and other organs.

How is hyperparathyroidism diagnosed?

Diagnosis of hyperparathyroidism involves a combination of blood tests, urine tests, and imaging studies to confirm excess parathyroid hormone (PTH) production and its effects on the body.

Key steps in diagnosis include:

• Blood tests — the hallmark finding is elevated blood calcium (hypercalcaemia) alongside high or inappropriately normal PTH levels. Additional tests may check kidney function, vitamin D levels, and phosphate levels, as these can help identify the underlying cause.

• Urine calcium measurement — a 24-hour urine collection assesses calcium excretion, which helps differentiate primary hyperparathyroidism from other causes of high calcium, such as familial hypocalciuric hypercalcaemia (a benign condition that does not require treatment).

• Bone density scan (DEXA) — measures bone mineral density to detect osteoporosis or bone loss caused by prolonged PTH excess.

• Imaging studies — ultrasound of the neck, sestamibi scans, or 4D CT scans may be used to locate overactive parathyroid glands, particularly if surgery is being considered.

• Kidney imaging — ultrasound or CT scans will be ordered to assess for kidney complications such as stones.

Because symptoms can be subtle or absent, routine blood tests often detect the condition before complications arise. A thorough evaluation ensures an accurate diagnosis and informs the best treatment approach.

What are the treatment options for hyperparathyroidism in Singapore? 

The choice of treatment for hyperparathyroidism depends on its type, underlying cause, severity, and the presence of complications. Management aims to restore calcium balance, protect bone and kidney health, and address symptoms.

• Surgery to remove overactive glands — parathyroidectomy is the main treatment for primary hyperparathyroidism, especially when blood calcium levels are significantly elevated or there is evidence of bone or kidney complications. This procedure involves removing the affected parathyroid gland(s) and can often be done using minimally invasive techniques.

• Monitoring for mild and asymptomatic cases — if the condition is mild and not causing symptoms or organ damage, regular monitoring may be recommended. This involves periodic checks of blood calcium, parathyroid hormone (PTH) levels, bone density, and kidney function to ensure stability.

• Medical management for secondary hyperparathyroidism — when the cause is chronic kidney disease or vitamin D deficiency, treatment focuses on correcting the underlying issue. This may include vitamin D supplements, calcium balance correction, and medications such as calcimimetics to reduce PTH levels.

• Lifestyle and dietary adjustments — in some cases, reducing dietary phosphorus (often found in processed foods and soft drinks) and ensuring adequate but not excessive calcium and vitamin D intake can help manage the condition. Staying hydrated is also important to reduce the risk of kidney stones.

• Treatment of underlying conditions — managing the root cause, whether it is a kidney disorder, malabsorption problem, or certain medications, is essential to long-term control of parathyroid overactivity.

What is the outlook for people with hyperparathyroidism?

With timely diagnosis and appropriate management, most people with hyperparathyroidism can expect a good long-term outlook. The prognosis depends largely on the type of the condition, the severity at diagnosis, and how quickly treatment is initiated.

• Primary hyperparathyroidism — surgical removal of the overactive gland(s) usually offers a permanent cure, with normal calcium and PTH levels restored soon after. Most symptoms, such as fatigue, bone pain, and mood changes, improve within weeks to months, and the risk of further bone or kidney damage is greatly reduced. Most of Dr. Dinesh’s patients demonstrate an explosive growth in bone after the operation. 

• Secondary hyperparathyroidism — the outlook depends on controlling the underlying cause, such as chronic kidney disease or vitamin D deficiency. With effective treatment, PTH levels can be brought back to a safer range, which helps protect bones and other organs from long-term harm.

• Tertiary hyperparathyroidism — in some cases, surgery may be required, especially when medical management fails to control excessive hormone production. After treatment, patients often see significant improvement in calcium balance and overall health.

• Importance of follow-up care — regular monitoring after treatment is crucial to detect any recurrence or lingering effects, especially for bone health and kidney function. Early intervention in case of relapse helps prevent complications.

When well managed, hyperparathyroidism does not usually shorten life expectancy, and patients can return to normal daily activities with improved quality of life.

Summary 

Hyperparathyroidism is a condition in which the parathyroid glands produce too much parathyroid hormone, disrupting calcium balance and affecting bone, kidney, and overall health. While some people may have mild or no symptoms, untreated cases can lead to serious complications such as osteoporosis, kidney stones, and cardiovascular problems. With proper diagnosis and treatment, whether through surgery, medication, or careful monitoring, most patients can achieve good outcomes and prevent long-term damage. 

If you have symptoms or concerns related to high calcium levels or overactive parathyroid glands, schedule a consultation with us at The Metabolic Clinic for a thorough evaluation and personalised management plan.

Frequently Asked Questions (FAQs)