17322 Parathyroid Scan

Overview

A parathyroid scan is a painless imaging test. It uses a tiny amount of a radioactive tracer to take pictures of your parathyroid glands. These are four small glands in your neck, each about the size of a grain of rice, that sit close to your thyroid gland. They make parathyroid hormone (PTH), which controls the level of calcium in your blood. The scan helps doctors find a gland that is working too hard, usually because it has a small benign (non-cancerous) growth called an adenoma. Knowing exactly where that gland is helps your surgeon plan a smaller, safer operation.

Yes. A parathyroid scan is a routine test in nuclear medicine departments. It is one of the standard ways to look for an overactive parathyroid gland when blood tests show high calcium and high parathyroid hormone.

It is used in adults of any age, but overactive parathyroid glands are most often found in women over 50. It can also be needed in people with kidney problems, people with a family history of parathyroid or hormone problems, and occasionally in children, usually when there is an inherited condition.

Symptoms

Common symptoms

• Often no symptoms at all. Many people are referred after a routine blood test shows a high calcium level.
• Feeling very tired, weak, or low in energy
• Aches and pains in the bones or muscles
• Feeling thirsty and passing more urine than usual
• Constipation or an upset stomach
• Kidney stones
• Low mood, poor concentration, or memory problems
• Thinning bones (osteoporosis) or broken bones from a minor fall

Symptoms in children

• Overactive parathyroid glands are rare in children. When they do happen, they are often linked to an inherited condition that runs in families.
• Possible signs are poor growth, bone pain, tiredness, constipation, and kidney stones.
• If a child has high calcium on a blood test, they should be seen by a specialist children's team.

Symptoms in older adults

• Symptoms can be mistaken for normal ageing, such as tiredness, low mood, confusion, or general weakness.
• Bone thinning and fractures after small falls are more common.
• Drinking less fluid because of thirst that is put down to habit can make calcium levels rise further, so keeping hydrated matters.

Causes

Main causes

• A single overactive parathyroid gland, usually caused by a small benign growth called an adenoma. This is the most common reason for the scan.
• All four glands being overactive, called hyperplasia. This is often linked to long-term kidney disease or to an inherited condition.
• Parathyroid cancer, which is very rare.
• Sometimes the scan picks up other tissue in the neck, such as thyroid nodules, that also takes up the tracer. This is usually harmless but may need a follow-up.
• The scan may also be done before neck surgery, to help the surgeon find the gland more easily.

Risk factors

• Being over 50, especially if you are a woman
• A family history of high calcium, parathyroid problems, or inherited hormone conditions
• Long-term kidney disease
• Having taken certain medicines for many years, such as some mood-stabilising medicines. Ask your doctor or pharmacist if this applies to you.
• Previous surgery or radiotherapy to the neck
• Low vitamin D levels, which can make parathyroid hormone rise. This is checked with a blood test before any scan.

When to see a doctor

See a doctor urgently if:

• Confusion, severe drowsiness, or unusual weakness that has come on quickly
• Vomiting that will not stop, or signs of dehydration
• A fast or irregular heartbeat
• Sudden severe back or side pain with blood in your urine
• Any severe reaction right after the tracer injection, such as rash, swelling, or trouble breathing. Tell the staff straight away.

Book a routine appointment if:

• A blood test has shown high calcium or high parathyroid hormone
• You keep getting kidney stones
• You have been told your bones are thinning, or you have had a fracture from a minor fall
• You have ongoing tiredness, thirst, constipation, or low mood and are not sure why
• You want to understand the results of your scan or what happens next

Diagnosis

The scan is only one part of the picture. Doctors first use blood tests to check your calcium and parathyroid hormone levels and to rule out other causes. If those point to an overactive parathyroid gland, a scan is used to find which gland it is and where exactly it sits. Your doctor puts all the results together before deciding on treatment.

Tests that may be done

• Blood tests for calcium, parathyroid hormone, vitamin D, and kidney function
• A urine test to measure how much calcium you pass
• A parathyroid scan, which is the test this article is about
• An ultrasound scan of the neck, which is quick, painless, and uses sound waves, not radiation
• Sometimes a specialised CT scan of the neck, if the first scans are unclear
• A bone density scan to check your bone strength

What to expect at your appointment

On the day, you can usually eat and drink normally. Your hospital will tell you whether to change or pause any medicines, so check with them beforehand and never stop a medicine on your own. When you arrive, a small needle is placed in a vein in your arm or hand and the tracer is injected. You may feel a brief cool feeling or a mild taste, which passes quickly. You then wait, often 15 to 30 minutes, while the tracer moves around your body. For the pictures, you lie on a padded bed and a large camera is moved close to your neck and chest. You need to stay very still, but you can breathe normally. Each set of pictures takes about 20 to 40 minutes. Some people have a second set two to three hours later, so bring something to read and a snack. Afterwards you can go home and do your normal activities. Drinking plenty of water helps clear the tracer. The tracer is safe, but for a few hours you may be asked to keep a little distance from pregnant women and small children. The staff will explain this and it varies slightly between hospitals.

Treatment

Treatment depends on what the scan and blood tests show. If one gland is overactive and you have symptoms or complications, an operation is usually the best option and often cures the problem. If your calcium is only mildly high and you feel well, your doctor may suggest watching and checking it over time. Treatment is always planned around your age, your symptoms, and your other health conditions.

Self-care at home

• Drink plenty of water each day unless your doctor has told you to limit fluids
• Keep a note of your symptoms, such as tiredness, thirst, or bone pain, so you can describe any changes
• Do not start high-dose calcium or vitamin D supplements without checking with your doctor or pharmacist, as they can raise your calcium level
• Stay active, including some weight-bearing exercise like walking, to help keep your bones strong
• Attend your follow-up blood tests, even if you feel well
• Tell any doctor or dentist treating you that you have had a parathyroid scan or have high calcium

Medical treatments

Some people do not need an operation. In that case, your doctor may simply check your blood tests every few months or once a year. If calcium levels need lowering, or if your bones need protecting, there are medicines that can help. These are chosen by a specialist and are started only after a full review. If you have kidney disease or low vitamin D, treating that is part of the plan. Your doctor or pharmacist will explain any medicine, its benefits, and possible side effects. Never start or stop medicines without speaking to them first.

When is surgery considered?

Surgery is usually recommended when the scan shows a single overactive gland and you have symptoms, kidney stones, thinning bones, or a very high calcium level. It may also be advised for younger people, because the problem tends to worsen over time. The operation is done through a small cut in the neck and often takes under an hour. Most people go home the next day or even the same day. Your surgeon will explain the risks and benefits, including a small chance of changes to your voice or to calcium levels afterwards.

Living with this condition

Waiting for results and planning treatment can feel unsettling, but most people manage well. If you have surgery, you may feel a bit tired for a week or two and your neck may be sore. Some people need calcium checks afterwards. Follow your team's advice about how much to rest and when you can return to work or driving.

Lifestyle tips

• Drink water regularly through the day rather than large amounts all at once
• Keep to a healthy, balanced diet with plenty of vegetables, and do not overdo salt
• Cut down on smoking and keep alcohol within recommended limits, as both affect bone health
• Aim for regular activity most days of the week
• Take care to avoid falls at home, especially if your bones are thin

Diet and exercise

There is no special diet that cures an overactive parathyroid gland. Eat normally and keep your calcium intake steady rather than very high or very low. Your doctor may check your vitamin D and advise on a supplement if it is low. For bones, weight-bearing exercise such as walking, climbing stairs, or light strength work helps. Gentle activity like swimming and cycling supports fitness and balance. Build up slowly, and ask your doctor before starting anything strenuous if you have bone thinning or fractures.

Mental health and emotional wellbeing

High calcium levels can affect mood, sleep, and concentration, and some people feel foggy or low. This often improves once the problem is treated, but it can be hard while you wait. Feeling anxious before a scan or an operation is completely normal. Tell your doctor if you feel persistently low, very anxious, or unable to cope. If you ever have thoughts of harming yourself, contact your local emergency number or a crisis line in your country straight away.

Prevention

You cannot usually prevent an overactive parathyroid gland, as it is most often caused by a small growth that happens for no clear reason. What you can do is spot it early with blood tests if you are at higher risk, and treat it before it affects your bones or kidneys.

Screening programmes

There is no routine screening for everyone. Blood calcium testing may be offered if you have a family history of an inherited parathyroid or hormone condition, long-term kidney disease, kidney stones, thinning bones, or if you take certain long-term medicines. If a close relative has a known inherited condition, ask your doctor whether other family members should be tested.

Complications

If left untreated

• Kidney stones and, over time, reduced kidney function
• Thinning bones and a higher chance of fractures after minor falls
• High blood pressure and strain on the heart and blood vessels
• Constipation, thirst, and passing a lot of urine
• Tiredness, low mood, and memory or concentration problems
• Very rarely, a sudden large rise in calcium, which is a medical emergency

Long-term outlook

The outlook is good. When the scan finds a single overactive gland, an operation usually fixes the problem for good, and most people feel better within weeks. Some people are safely monitored without surgery for many years. Either way, regular check-ups help keep you well. Many people find their energy and mood improve once their calcium is back to normal.

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