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Endocrine Surgery · Cleveland Clinic London

Hypercalcaemia &
Hyperparathyroidism

Raised calcium is a common but often under-investigated finding. For many patients, it is the cause of years of debilitating symptoms — and the treatment is straightforward. Mr Smellie offers expert assessment and parathyroid surgery at Cleveland Clinic London.

Raised calcium
Elevated PTH
Parathyroid adenoma
Day-case surgery available
Same-week appointments
Important — if you have been told your calcium is raised
Patients with hypercalcaemia who have a high or DETECTABLE PTH should be investigated for primary hyperparathyroidism. This is a treatable condition — and in many cases, the surgery is straightforward and can be performed as a day case.

Some patients are wrongly told that because their PTH is within the normal range, they do not have primary hyperparathyroidism. This is incorrect. In any other cause of hypercalcaemia — cancer, vitamin D excess, sarcoidosis — the PTH is completely undetectable, suppressed by the high calcium. Put simply: if there is a detectable PTH in the presence of hypercalcaemia, primary hyperparathyroidism is the highly likely cause and specialist assessment is warranted.

Hypercalcaemia — a common but overlooked diagnosis

Hypercalcaemia — raised calcium in the blood — is detected on routine blood testing in a significant number of patients each year. Despite being common, many patients go without a clear diagnosis for months or even years, continuing to experience symptoms that significantly affect their day-to-day quality of life.

The most common cause is primary hyperparathyroidism — an overactive parathyroid gland, usually caused by a benign adenoma. The parathyroid glands are four small glands in the neck that regulate calcium levels. When one becomes overactive, calcium rises — and stays raised — causing a constellation of symptoms that can be mistaken for depression, chronic fatigue, fibromyalgia, or simply "getting older."

The key diagnostic step is simple: if calcium is raised, PTH should be measured. A PTH that is elevated — or even within the normal range but detectable in the context of a high calcium — points strongly towards primary hyperparathyroidism and warrants specialist assessment.

Fatigue & low energy
Low mood & depression
Anxiety
Brain fog & poor concentration
Memory problems
Muscle weakness
Bone & joint pain
Kidney stones
Increased thirst & urination
Constipation
Nausea
Osteoporosis
Abdominal discomfort
Poor sleep

Highlighted symptoms are those most commonly reported as most quality-of-life impairing.

How primary hyperparathyroidism is diagnosed
1
Raised serum calcium
Detected on routine blood testing — often incidentally. May have been present for some time before specialist referral.
2
PTH — high or DETECTABLE
PTH should be suppressed when calcium is high. A PTH that is elevated — or merely detectable — in the context of hypercalcaemia is strongly suggestive of primary hyperparathyroidism.

Some patients are wrongly told that a "normal range" PTH excludes the diagnosis. This is not correct. In hypercalcaemia from any other cause — malignancy, vitamin D toxicity, sarcoidosis — PTH is completely undetectable. A detectable PTH alongside a raised calcium therefore points strongly to primary hyperparathyroidism, regardless of whether the PTH number falls within the laboratory reference range.
3
Localisation imaging
Ultrasound, sestamibi scan, 4D CT or MRI can identify an overactive gland. Imaging helps plan the surgical approach but does not exclude the diagnosis if negative.
4
Specialist review
Mr Smellie reviews all investigations together to confirm the diagnosis, assess fitness for surgery and agree the operative approach with the patient.

"Many patients with hypercalcaemia live for years with debilitating symptoms without ever receiving a clear diagnosis or treatment. If your calcium is raised and your PTH is high — or even detectable — primary hyperparathyroidism is the likely cause. The treatment is well-established, the surgery is straightforward, and for many patients, the improvement in quality of life after a successful operation is transformative."

Mr W. James Smellie · Consultant Endocrine Surgeon, Cleveland Clinic London
Surgical Treatment

Parathyroid surgery — your options

Parathyroidectomy — surgical removal of the overactive parathyroid gland — is the only curative treatment for primary hyperparathyroidism. Mr Smellie offers both targeted minimally invasive surgery and traditional four-gland exploration. Patients may specify their preference, or discuss with the team which approach best suits their individual case based on pre-operative imaging and biochemistry.

Option 1

Targeted Minimally Invasive Parathyroidectomy with IOPTH

Where pre-operative imaging has identified a single overactive gland, a targeted approach allows removal through a small focused incision. Intraoperative PTH monitoring (IOPTH) provides real-time confirmation that the correct gland has been removed — PTH falls by more than 50% within minutes of successful excision, giving high confidence of cure without the need for full neck exploration.

Smaller incision, less dissection
Day-case procedure in most patients
Real-time cure confirmation with IOPTH
High success rate when imaging concordant
Faster recovery
Option 2

Four-Gland Bilateral Neck Exploration

The traditional and definitive approach — all four parathyroid glands are identified and assessed at surgery. This is particularly appropriate where pre-operative imaging is inconclusive or negative, where multiglandular disease is suspected (e.g. in MEN syndromes), or where a patient specifically requests it for the added reassurance of a complete assessment. IOPTH can also be used during four-gland exploration.

Comprehensive assessment of all four glands
Preferred where imaging is negative or discordant
Essential for suspected multiglandular disease
Patient choice — can be requested specifically
Gold standard long-term cure rate

Intraoperative PTH Monitoring

Intraoperative PTH monitoring (IOPTH) is one of the most important advances in parathyroid surgery. PTH has a very short half-life — approximately 3–5 minutes. This means that if the overactive gland is successfully removed, PTH levels in the blood fall rapidly and measurably within minutes of excision, providing real-time biological confirmation of cure in the operating theatre.

A drop of more than 50% from the pre-excision baseline, combined with normalisation into the reference range, is the accepted criterion for a successful operation — the Miami Criterion — and allows the surgeon to close with confidence that the correct gland has been removed.

How IOPTH works — step by step
1
Baseline PTH measured
Blood sample taken at the start of surgery to establish the pre-excision PTH level.
2
Overactive gland removed
The suspected gland is excised based on pre-operative imaging and intraoperative findings.
3
PTH measured at 5 and 10 minutes
Blood samples are taken 5 and 10 minutes after excision. The rapid assay returns results within minutes.
4
Cure confirmed intraoperatively
A fall of >50% confirms successful removal. Surgery concludes with confidence. If PTH does not fall, further exploration is performed.
Why Choose Cleveland Clinic London

Prompt, personalised care

Mr Smellie treats many patients at Cleveland Clinic London who have a confirmed or suspected diagnosis of primary hyperparathyroidism but are not prepared to remain untreated on NHS waiting lists — and who value the prompt, personal and internationally excellent care that Cleveland Clinic London provides.

NHS pathway — typical experience
Long waiting times from referral to surgery — often 12–24 months or more
Multiple appointments across different departments before treatment
Symptoms continuing — and often worsening — throughout the wait
Limited ability to choose surgeon or discuss operative approach
Asymptomatic patients may not meet thresholds for surgical referral
Cleveland Clinic London with Mr Smellie
Same-week consultation, prompt surgery date agreed
All investigations coordinated at one world-class facility
Treatment without unnecessary delay — symptoms addressed promptly
Full discussion of targeted vs 4-gland approach — patient preference respected
Insured and self-pay patients equally welcome — transparent pricing
Common Questions

Frequently asked questions

I've been told my calcium is high but no one has told me why. What should I ask?
Ask your GP to measure your PTH (parathyroid hormone) if it has not already been done. A PTH that is elevated — or simply detectable — in the setting of a raised calcium is the key diagnostic finding for primary hyperparathyroidism. This is an important and treatable condition that is frequently underinvestigated.
My PTH is "normal" — could I still have hyperparathyroidism?
Yes. In primary hyperparathyroidism, PTH should be suppressed by the high calcium — so a PTH that is merely detectable or in the lower half of the normal range, in the presence of hypercalcaemia, is still inappropriately elevated and warrants specialist assessment. This is a common source of confusion: some patients are told that because their PTH is within the normal laboratory range, primary hyperparathyroidism has been excluded. This is incorrect. In hypercalcaemia caused by anything else — malignancy, vitamin D excess, sarcoidosis — the PTH is completely undetectable. A detectable PTH in the context of a raised calcium is therefore highly likely to represent primary hyperparathyroidism, and should not be dismissed.
Is the surgery safe?
Parathyroidectomy is a well-established, safe operation. In experienced hands, the cure rate for a single adenoma with targeted surgery and IOPTH is over 95–98%. The main risks are injury to the recurrent laryngeal nerve (affecting the voice) and temporary or permanent low calcium after surgery — both of which Mr Smellie takes specific steps to minimise.
Can I choose which type of surgery I have?
Yes. Patients may specify four-gland exploration or targeted minimally invasive parathyroidectomy with IOPTH, or discuss with Mr Smellie and the team what approach is most appropriate for their individual case. The choice is guided by pre-operative imaging, biochemistry, and patient preference.
Will I need to stay in hospital?
In most cases, parathyroid surgery is performed as a day case or with a single overnight stay. The procedure is typically performed under general anaesthetic and lasts 45–90 minutes depending on the approach. Most patients are home the same day or the morning after surgery.
How quickly will I feel better after surgery?
Many patients notice an improvement in energy, mood and cognitive clarity within days to weeks of a successful operation. Bone and muscle symptoms typically improve over weeks to months as calcium normalises. Most patients describe the improvement in quality of life as significant and lasting.
Does my insurer cover this?
Primary hyperparathyroidism is a medical condition and is covered by most UK private health insurers. Mr Smellie is BUPA Platinum recognised and accepts all major insurers. Please check with your insurer before booking. Self-pay patients are also welcome and transparent pricing is available on request.

Concerned about raised calcium?

Mr Smellie offers prompt assessment and expert parathyroid surgery at Cleveland Clinic London.
Same-week appointments available. Insured and self-pay patients welcome.

0800 098 1942
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