Hyperparathyroidism can lead to weight gain

Patient information for primary hyperparathyroidism (pHPT)
Parathyroid disease, unlike thyroid disease, is relatively unknown, although parathyroid disease patients are the second largest group of patients who have surgery on hormone-producing glands.
More and more patients are diagnosed with overactive parathyroid glands at an earlier and earlier point in time - often as a coincidental finding in blood tests - without any pronounced symptoms being present. Nevertheless, the disease usually leads to a relevant reduction in quality of life in the course of the disease.

The parathyroid glands
As their name suggests, the parathyroid glands are located next to the thyroid gland. The technical term is Glandulae parathyreoideae.
Most people have four parathyroid glands, which are located on the side of or behind the thyroid gland. About 3-5% of people have more than 4 parathyroid glands. Usually these are about 3x3x1mm, which is about the size of a pea, and each weigh 20-40mg. There are seldom variations in the position of the parathyroid glands that can be explained by their developmental history. One of the difficulties of parathyroid surgery lies in this positional variability of the parathyroid glands.
The parathyroid glands produce parathyroid hormone (PTH), which is important for calcium metabolism. If the calcium level in the blood is too low, the PTH causes more calcium to be absorbed from food, released from the bones and reabsorbed in the kidneys until the concentration in the blood is normalized again. The antagonist of the parathyroid hormone is the calcitonin formed in the thyroid gland, which triggers opposing mechanisms in the body when the calcium blood level is too high.

Overactive parathyroid glands
In primary overactive parathyroid glands, there is a secretion of parathyroid hormone that goes beyond the needs of the organism, the cause of which is not known. This results in a pathological increase in the calcium level in the blood (hypercalcemia). In the vast majority of cases, there is a benign tumor from a single parathyroid gland (approx. 85%). Two (5-10%) or more than two parathyroid glands (approx. 10%) are more rarely affected. Parathyroid hyperfunction due to a malignant parathyroid tumor is very rare (1%). In 5% of cases, primary hyperparathyroidism is based on a familial hereditary form.
So-called secondary hyperparathyroidism usually occurs in patients with kidney failure. In patients with this form of hyperparathyroidism, all of the parathyroid glands are abnormally enlarged.
There are around 25-30 new cases per 100,000 inhabitants per year. Women are affected much more often; the ratio between sick men and women is 1: 3.
The increased production and release of parathyroid hormone, through its effect on the bones and the kidneys, leads to an increase in the calcium level in the blood above the upper normal value (hypercalcemia). This leads to functional disorders in many organs. If the hypercalcaemia persists, subsequent damage to the organs that cannot be corrected can occur.

How is the diagnosis of primary hyperparathyroidism made?
Most of the time, the diagnosis of primary hyperparathyroidism is determined by chance in the course of other examinations during blood tests by an elevated calcium level above the normal value.
For a correct diagnosis, multiple increased levels of calcium in the blood should have been measured over several blood samples. In addition, the parathyroid hormone concentration must be measured. Multiple documented hypercalcaemia in combination with an increased parathyroid hormone level is evidence of primary hyperparathyroidism. Other causes that can lead to hypercalcaemia must be ruled out before a definitive diagnosis is made.

Typical symptoms are mainly caused by the hypercalcaemia associated with the overactive parathyroid glands. These symptoms are mostly reversible; that is, if the calcium level is normalized by a successful operation, a complete normalization can be expected.
In addition to neuropsychiatric symptoms such as tiredness, weakness, tendency to depression, disorientation and memory disorders, kidney-related symptoms, excessive thirst (polydipsia) and increased urine excretion (polyuria) can occur. Symptoms of the gastrointestinal tract, such as loss of appetite, vomiting, weight loss and constipation, can be caused by hypercalcaemia, as can cardiovascular disorders (increased heart rate, arrhythmia, high blood pressure).
The most common organ manifestation is kidney stone disease, which can lead to complete calcification of the kidney tissue.
There are remodeling processes on the skeleton, increasing decalcification of the bones. This can lead to back and joint pain. In advanced disease, spontaneous fractures can occur.
With very high calcium levels, life-threatening crises can occur, which can lead to acute kidney failure and brain dysfunction up to a coma.
Because of the frequent occurrence of kidney stones, bone pain and symptoms in the gastrointestinal tract (stomach and duodenal ulcers), the term “stone, leg and stomach pain” was often used in the past.

How is primary hyperparathyroidism treated?
Although there are drugs that can lower calcium levels in the short term, definitive correction of hypercalcemia can only be achieved through surgery. Sometimes the symptoms are mild and barely noticeable clinically. In particular, mild neuropsychological symptoms can often only be recognized as such after successful surgical correction of the hypercalcemia through an improvement in general well-being. In the case of absolutely symptom-free patients, under certain conditions and only slightly increased calcium levels, a wait-and-see attitude can be adopted in exceptional cases.
The operation with removal of the pathologically altered parathyroid gland (s) is the only therapeutic option. It is almost always successful in the hands of an experienced parathyroid surgeon. In the standard operation for the treatment of primary hyperparathyroidism, all four parathyroid glands are exposed through a transverse access on the neck. All abnormally enlarged parathyroid glands are removed. Most often it is a single enlarged parathyroid (85% of cases). If all four glands are enlarged (10-15% of cases), three and a half glands are removed and half a gland is left.
This operation, which has already been carried out more than 1000 times in our clinic, is cured in over 95% of cases. The operation is considered extremely safe. Injuries to the vocal cord nerves are observed in less than 1% of cases; the incidence of parathyroid hypofunction after surgery is approx. 2-4%.

Minimally invasive parathyroid surgery
For several years now, the minimally invasive removal of parathyroid glands has been carried out in our surgical clinic, which is an internationally renowned center for parathyroid surgery. The enlarged parathyroid gland is removed via a minimal incision of approx. 2 cm in length. The prerequisite for performing such a small access is knowledge of the location of the enlarged gland and the ability to check the success of the operation intraoperatively using a rapid parathyroid hormone test. More information at: www.nebenschilddruese.de.