Normocalcemic Primary & Secondary Hyperparathyroidism Symptoms, Causes, Diagnosis, Treatment

Normocalcemic hyperparathyroidism is a disorder in which the parathyroid glands, which are positioned in the neck, create an excessive amount of parathyroid hormone. This condition is characterized by normal calcium levels (PTH). Calcium homeostasis is aided by this hormone. When a person has normocalcemic hyperparathyroidism, their blood calcium levels are normal but their PTH levels are higher.

Normocalcemic Hyperparathyroidism Definition

Normocalcemic hyperparathyroidism is considered when the levels of parathyroid hormone stay high even after the serum calcium or ionized calcium levels have been corrected at least twice over at least six months. 

Normocalcemic Primary & Secondary Hyperparathyroidism

When parathyroid hormone levels are elevated yet serum calcium levels are normal, this disease is known as normocalcemic hyperparathyroidism (nHPT). It can be primary (nPHPT) if one or more parathyroids secrete PTH autonomously, or secondary (nSHPT) if a low calcium stimulus causes a reflex increase.

In patients with normocalcemic secondary hyperparathyroidism (nSHPT), an elevated PTH level is a response to a low calcium stimulus that can have a number of different origins. PTH levels stay increased for as long as the low calcium stimulus is present, but they quickly revert to normal once the stimulus is eliminated. All four parathyroid glands commonly exhibit hyperplasia in patients with secondary hyperparathyroidism.

Prior to making a diagnosis of normocalcemic primary hyperparathyroidism, it is crucial to rule out normocalcemic secondary hyperparathyroidism with a complete medical history, physical exam, and targeted laboratory studies. This is because medical treatment for nSHPT is targeted at the reasons of the low calcium stimulus, whereas surgical parathyroidectomy may be required for nPHPT.

Normocalcemic Hyperparathyroidism Symptoms

There are variety of mild to severe normocalcemic hyperparathyroidism symptoms, such as:

• Tiredness
• Anxiety
• Tummy ache
• Emesis
• Throwing up
• Constipation
• Bone pain
• Heightened fracture risk

It's possible for some persons with normocalcemic hyperparathyroidism to have no symptoms at all or to have very minor symptoms that are simple to ignore. In some situations, a regular blood test or physical examination may reveal the problem.

Normocalcemic Hyperparathyroidism Causes

Normocalcemic primary hyperparathyroidism (nPHPT) can be brought on by a single or multi adenomas or hyperplasia of the parathyroid gland. The risk of developing normocalcemic primary hyperparathyroidism (nPHPT) is increased when radiation is delivered to the neck.

Normocalcemic secondary hyperparathyroidism (nSHPT) can be brought on by a lack of vitamin D, kidney problems, bowel syndrome, weight loss surgery, restricted calcium intake, renal calcium leakage, or unexplained hypercalciuria. Terminal renal impairment is the most frequent cause, which results in decreased vitamin D activation, decreased intestinal calcium absorption, hypocalcemia, and severe secondary hyperparathyroidism.

Normocalcemic Hyperparathyroidism Diagnosis

In the majority of situations, normocalcemic primary hyperparathyroidism (nPHPT) is diagnosed when patients suffering from osteoporosis or renal stones undergo proactive investigation. Serum-ionized calcium, phosphorus, parathyroid hormone (PTH), estimated glomerular filtration rate (eGFR), 25-hydroxyvitamin D, and urine calcium excretion would be reasonable preliminary investigations in such cases. These tests and a thorough look at the patient's prescription drugs would be enough to rule out normocalcemic secondary hyperparathyroidism (nSHPT) and make a diagnosis of nPHPT. Other tests, like serum Mg and liver function tests, are required based on clinical circumstances.

Normocalcemic Hyperparathyroidism Treatment

The only treatment that is guaranteed to be successful for primary hyperparathyroidism, regardless of whether it is normocalcemic or hypercalcemic, is surgery of the parathyroid glands. At now, there is no alternative to successful surgery that can provide the same level of medical benefit. The guidelines and criteria for parathyroid surgery made by international experts on Asymptomatic Primary Hyperparathyroidism can be equally applicable to normocalcemic primary hyperparathyroidism (nPHPT). These include 

• Age below 50 years
• Osteoporosis
• Creatinine clearance 60 ml/min
• Urine calcium >400 mg/24 hours
• Nephrolithiasis

Studies have indicated an increase in bone mineral density after surgical intervention. Renal function is conserved, and the danger of recurring renal calculi is greatly reduced even though it is not completely eradicated. The benefits of parathyroid surgery in treating neuropsychiatric or cardiovascular problems are not yet sufficiently supported by the available research.