Parathyroid Disease

Parathyroid Disease

What is the parathyroid gland?

Parathyroid glands are 3-4mm glands located behind the thyroid gland, which is present in the neck. They are four in number. They play an important role in maintaining normal calcium levels in the body. Any tumour of the parathyroid glands can cause increased calcium levels in the body.

What is primary hyperparathyroidism?

It is a condition in which your blood calcium levels are elevated, due to an increase in parathyroid hormone levels.

What causes primary hyperparathyroidism (increased calcium levels)?

The commonest cause is a tumour (enlarged gland) affecting one of your parathyroid glands.

In around 10-15% of patients all the parathyroid glands or rarely two or more may be enlarged.

What are the important questions to be answered in patients with increased calcium levels (primary hyperparathyroidism)?

  1. Does this patient have the disease?It is confirmed by the presence of increased calcium, in the presence of increased parathyroid hormone levels.
  2. Does the patient need an operation?If you have one or more of the following problems, surgery will be necessary
    • Calcium level more than 1mg above the upper limit of normal
    • Kidney stones
    • Pancreatic calculi/ pancreatitis in the past
    • Weak bones – Decreased bone mineral density/osteoporosis/ Brown tumours
    • Subtle memory loss, irritability, mood changes, depression
  3. What type of operation is appropriate?Your surgeon will recommend one of the following types of surgery’s , based on the type of parathyroid gland disease.
    • Four gland exploration
    • Focused minimally invasive approach
    • Scarless Endoscopic approach

How do you confirm primary hyperparathyroidism?

If your serum calcium is more than 10.6mg with elevated Parathyroid hormone (PTH) level, a diagnosis of primary hyperparathyroidism is likely. Tests which are then done to confirm the diagnosis include urinary calcium measurements, ultrasound scan of the neck and technetium sestamibi uptake scan.

What are the consequences of untreated hyperparathyroidism?

The tumour in the parathyroid gland produces excessive parathyroid hormones and this hormone in turn acts on the bones and weakens it by taking out calcium from it , and this excessive calcium in the blood is excreted through the kidneys. But the calcium load becomes so much that there can be deposition of calcium in the kidneys and causes kidney stones. Sometimes it gets deposited in the pancreas and causes severe pain abdomen (pancreatitis). This excess calcium can act on your brain and cause mood changes, memory loss and irritability.

Due to the continuous removal of the calcium from the bones, they become weak and lead to fractures, bony pains, weakness and bone tumours.

What are the other investigations required for confirmation of primary hyperparathyroidism?

After confirming the diagnosis with blood tests, our next step is to locate the tumour. The following tests are done to identify the tumour

  1. Ultrasound of the neck: Ultrasound is a good investigation, when done by experienced operators. 
  2. Sestamibi scan: A small dose of radioactive technetium labelled sestamibi is given as an injection. This compound is concentrated by abnormal parathyroid glands, which are then identified using a gamma camera.

When do we do 4D CT scan of the neck?

It is done when ultrasound and sestamibi scans have not picked up the lesion or both are showing different lesions.

How is a 4D CT different from a routine CT?

4D CT is a specialized imaging technique which is used to identify abnormal parathyroid glands. For this scan the patient is first positioned in a specific way to minimize interference. A specified amount of contrast is then given and images are acquired in three phases – pre contrast , arterial and venous. The timing of these phases helps to differentiate parathyroid tissue from other surrounding structures.

What is a concordant lesion?

If two of the three tests i.e. ultrasound, sestamibi scan and 4D CT are showing the same lesion than the lesion is called concordant lesion and the chance of cure in these patient is >95%.

Can ultrasound/sestamibi/4D CT scans can fail?

Some 10-15% of the patients can have abnormality in multiple parathyroid glands an entity called hyperplasia of parathyroid glands. These are sometimes due to a genetic mutation. Rarely two or more lesions can also cause the tests to fail.

What are the other tests done in suspected primary hyperparathyroidism?

  1. Bone mineral density: The patients bones become very weak and brittle (osteoporotic) particularly in the forearm bone (Radius).
  2. Ultrasound of the abdomen: This is done to check for stones in the kidney, sometimes in the pancreas.
  3. Serum prolactin: Some patients can have a genetic problem called Multiple Endocrine Neoplasia Type1 (MEN 1). This is commoner in younger patients. Prolactin level is tested to look for other problems associated with MEN 1.

My ultrasound, sestamibi and 4D-CT scan are negative. What is the next step I should take?

You may need detailed assessment by an experienced team of doctors including an endocrinologist, radiologists, endocrine surgeon and nuclear physician. The options which may be considered are –

  1. Choline-PET CT: It is like a PET scan and is available in limited centre in India.
  2. Selective venous sampling in, which your doctor will collect the blood sample and assess the serum parathyroid hormone level at different levels in your neck, it will help in localizing the lesion to one particular region.
  3. To operate and explore all the parathyroid glands. An experienced surgeon will try to identify the abnormal gland under direct vision, during surgery and then excise it.

What is intra-operative parathyroid hormone assessment (IOPTH)?

Parathyroid hormone levels are assessed just before the operation (baseline) and 10 min after removal of the tumour. If your 10 minutes post-operative PTH level decreases by > 50% from the baseline then the surgery is considered to be successful.

What is the treatment if I have MEN syndrome (multiple endocrine neoplasia) with hypercalcemia?

Patients from MEN syndrome and hyperplasia should be treated totally differently. These patients have a genetic mutation and all the four parathyroid glands will be abnormal. Here the ultrasound, Sestamibi and 4D-CTscan may show one or multiple lesions and sometimes can mislead the surgeon. But these tests are useful to locate any unusually located parathyroids.

The patients with MEN syndrome and Hyperplasia will need either

  1. Three and half parathyroid gland excision along with cervical thymectomy (as 10-15% of patients can have supernumerary or ectopic parathyroid gland in the thymus)
  2. Three parathyroid gland excision along with cervical thymectomy.

What is redo parathyroid surgery?

It is one of the most challenging aspects of parathyroid surgery. It is an operation to treat hyperparathyroidism after the first operation has failed to achieve cure. The risks of redo surgery are higher than for the original surgery, and it should be performed only by an expert surgeon.

Some of the reasons for a failed parathyroid surgery are a missed adenoma, surgeon removing only one gland when the disease actually affects all 4 glands (hyperplasia), and ectopic location of the abnormal parathyroid such as inside the chest or behind the trachea.

What is secondary hyperparathyroidism?

It is a condition where your parathyroid hormone levels are elevated but with normal calcium levels. The problem here is not with the parathyroid gland but with some other organs in the body. The common causes are due

  1. Vitamin D deficiency
  2. Renal Failure etc.

What is Neonatal hyperparathyroidism?

This is an extremely rare condition where your newborn will present with failure to thrive, with increased calcium levels along with increased parathyroid hormone levels. These babies have a genetic mutation which causes the parathyroid gland to make excess hormone.

What is the treatment for Neonatal hyperparathyroidism?

The best treatment is total parathyroidectomy + lifelong calcium supplementation

The other treatment is to do total parathyroidectomy + autotransplantation of small part of the gland in the forearm.

I had parathyroid surgery but by Calcium and PTH levels have not changed. What could be the possible problem?

If your calcium and PTH have not changed after your surgery it is called persistent hyperparathyroidism. The common causes are

  1. Failure to identify or remove the parathyroid adenoma.
  2. Presence of more than one tumour. Such a tumour could also be present in unusual locations, such as in the chest.
  3. Inadequate removal of hyperfunctioning glands in multiple gland disease.
  4. In some patients hyperparathyroidism can reappear several years after successful surgery.

How is a patient with persistent hyperparathyroidism or a patient with recurrent hyperparathyroidism managed?

The first thing to do is to reconfirm the diagnosis. We need to assess whether the patient has single parathyroid gland disease or multiple parathyroid gland disease.We also need to rule out a mild inherited condition called Benign familiar hypocalciuric hypercalcemia (BFHH).

After confirming the disease by blood and urine tests the following steps can be taken

  1. Review the old imaging reports
    • Ultrasound of the neck
    • Sestamibi scan
  2. Review the biopsy report of the first surgery by an experienced pathologist (slide and block review)
  3. Review the previous operation details if possible, with a discussion of the problems encountered during initial surgery.
  4. To do a 4D CT scan of the neck or Choline-PET CT
  5. Use of intraoperative PTH and frozen section during repeat surgery(intraoperative quick biopsy report).

How is parathyroid surgery done?

The surgeon will do an ultrasound of the neck just before surgery to pinpoint the tumour. He will then make a 2-3cm incision over the lesion and excise it. After excising the tumour the surgeon will re-send parathyroid hormone levels to confirm the decrease in PTH levels before closing the operation.

What are the instructions a patient needs to follow before surgery?

Patient can have normal dinner the night before surgery. He then needs to stay on empty stomach without eating or drinking anything from 12 midnight till the time of surgery.

When will the patient be admitted?

Patient can come in morning at 8am on the day of surgery to the admission block in Apollo health city Jubilee hills for admission.

For how long does the patient have to stay in the hospital after surgery?

Usually the patient will be discharged in 1 or 2 days. Occasionally the calcium levels may become very low after surgery, and some patients may need to stay in hospital for 3 to 4 days in order to normalise calcium levels.

Can the patient eat and talk after the surgery?

The patient can take clear liquids 4 hours after surgery and if he has no vomiting can take normal diet thereafter. There is no restriction on talking.

When can he resume the normal activities?

He can start walking on the day of surgery and can resume normal activities after one week. Avoid driving, sudden neck movements and lifting heavy weight for one month.

What are the complications of parathyroid surgery?

Parathyroidectomy is a safe surgery and complications are rare. Some of the problems which are occasionally seen are

  1. Failure to achieve normal calcium levels can happen in 1-5% of patients, and depends on surgeon experience as well as the type of parathyroid problem
  2. Postoperative hypocalcemia(low calcium levels)- This can be due to suppression of the normal parathyroid glands by the tumour, or occasionally due to damage to the parathyroid glands during four gland exploration. The lowest calcium level is seen at 24- 48 hours after surgery, so patients are carefully monitored for any symptoms or signs.
  3. Recurrent laryngeal nerve injury – It is a nerve injury which causes voice change. It is very rare in the hands of experienced surgeons and is seen in less than 1% of cases.

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