It is a rare endocrine disorder in which the parathyroid glands do not secrete normal levels of parathyroid hormone continuously.
These parathyroid glands may normally be present in the human body in a number of four, however it is possible that they are only two or even six.
They are located in the anterior area of the neck as well as in the back of the thyroid gland.
Parathyroid hormone is the hormone that regulates calcium levels in the body.
If these levels decrease the cells present in these glands elaborate and release the hormone in the blood and stimulates the synthesis of vitamin D in the kidney.
This vitamin increases the absorption of calcium in the intestines and this contributes to the increase in the level of calcium present in the blood.
On the other hand, the secretion of the hormone causes the kidney to lose phosphorus and produce a drop in phosphorus levels in the blood, so this hormone is essential to maintain the balance of both calcium and phosphorus.
When the level of calcium in the blood is normalized, the hormone is not produced by the parathyroid glands.
Calcium is one of the essential elements in the formation of bones and teeth.
When this element is found, it does not appear in the necessary quantities and in a prolonged way in the organism, so it will prevent the formation of teeth and bones, increasing the risk of fractures.
In the same way, if calcium is found in higher than normal amounts and continuously, what is called hyperparathyroidism .
That calcium that is produced in excess is deposited in the tissues of the kidney, in the walls of the blood vessels and in the joints, calcifying or hardening them and causing their malfunction.
The limits that are considered normal are given by a concentration of calcium in the blood that varies between 8.5 and 10.5 mg / dL or from 2.1 to 2.6 mol / L.
When there are disorders that cause a reduction or a continued absence of the production of parathyroid hormone, it causes a decrease in the normal values in the calcium figures, which is called hypocalcemia .
While high phosphorus values, what is called hyperphosphatemia .
The causes that cause hypoparathyroidism can be divided into three groups, whose classification is made according to conceptual and functional criteria.
This classification includes all those disorders that are provoked in the parathyroid glands.
These disorders are the characteristic deficiencies of the decrease or absence of parathyroid hormone in the blood and its consequents, low levels of calcium and high levels of phosphorus constantly.
- Post-surgical hypoparathyroidism: This is one of the most frequent causes of hypoparathyroidism, and they are originated when the surgical removal of the parathyroid glands is performed, due to accidental damage or because it is necessary, as in the case of a recommended treatment for respiratory diseases. the thyroid gland, or in treatments for cancer of the throat or neck.
- Autoimmune disease: The body’s immune system can generate antibodies that act against the parathyroid tissues and try to block them as if they were foreign bodies. In this process, the parathyroid glands usually suspend the production of parathyroid hormone.
- Hereditary hypoparathyroidism: The absence of parathyroid glands can be of congenital origin, from birth, as is the case of Di George syndrome . Some cases of hereditary hypoparathyroidism can be related to hormonal insufficiencies in other endocrine glands such as the thyroid gland, the adrenal glands and the pancreas, in the case of diabetes mellitus.
- Radioactive treatment for the treatment of cancer in the face or neck: Radiation treatments can destroy the parathyroid glands, this condition occurs when radiotherapy treatments are performed on the face and neck or treatments with radioactive iodine.
Low levels of magnesium or hypomagnesemia in the blood cause hypocalcemia since normal levels of magnesium are required for optimal secretion of parathyroid hormone.
In this case the parathyroid hormone is made and released into the blood, but this hormone is not effective because the organs where it has to act as are the bones and kidneys.
That is, they do not respond to the effects of the hormone, so even when it is segregating there is little calcium in the blood.
This induces the glands to produce even more hormones, but this is still ineffective, it is as if it were not being manufactured in the right amounts.
When it comes to “true” hypoparathyroidism, there are no hormones or they occur in very small amounts.
In pseudohypoparathyroidism, it is a hereditary disorder characterized by signs and symptoms similar to those of hypoparathyroidism, but which are associated with characteristic faults of skeletal development.
The levels of calcium in the blood decrease and cause the symptoms of hypoparathyroidism.
When the calcium decreases occur little significant and in a prolonged period of time.
The symptoms that appear are of very little intensity, but if this decrease in calcium is considerable or if it occurs abruptly, the symptoms that appear are of greater magnitude.
Hypocalcemia presents symptoms in cases of primary hypoparathyroidism, while in pseudohypoparathyroidism they usually appear in both forms.
Symptoms in the case of secondary hypoparathyroidism, are associated with the decline of Magnesium in blood.
Usually, hypocalcemia occurs in hereditary hypoparathyroidism and pseudohypoparathyroidism in a gradual manner and is associated with deterioration in the development of the sign that does not occur in the other types of hypoparathyroidism.
The typical symptoms that occur when hypocalcemia occurs are the following:
Neuromuscular alterations: When there is a decrease in calcium in the blood, there is an increase in the excitability of the muscles and an innervation of the nerves.
This gives rise to spasms in the muscles, sensations of tingling and cramps around the mouth, in the arms and throat that affect the larynx, causing breathing difficulties, spasms in the hands and feet, they can even produce seizures , especially in the case of children.
These signs of tetany, are known as signs of Chvostek and Trousseau.
Mental alterations: This type of alterations occur from irritability to levels of depression , neurosis and psychosis. State of consciousness diminished.
Alterations in the central nervous system: There may be episodes of parkinsonism, memory loss and multiple involuntary movements in extremities.
In some cases, individuals with maintained hypocalcemia may present intracranial calcifications visible by X-rays, which justify the presence of parkinsonian type syndromes.
The cardiac alterations: This deficiency produces some anomalies in what refers to the conduction of the electrical stimulus in the heart and they manifest in the form of arrhythmias, of prolongations in the QT interval, of alterations of the T wave and of cardiac blocks. Cardiac insufficiencies may also occur.
Alterations in the skin and in the accessories: Symptoms appear as dry and scaly skin, brittle nails, dry and rough hair. Symptoms such as alopecia may also occur.
Skin infections, fungal infections such as candidiasis occur more frequently. These alterations occur especially in cases of hereditary hypoparathyroidism when it is associated with insufficiencies of other endocrine glands.
Ocular alterations: In hypocalcemias that have a long duration, the appearance of cataracts is observed due to the alterations of the lens.
In children it is very frequent the appearance of dental anomalies such as defective enamels, little dental development and a delay in the eruption of the teeth.
There are usually alterations according to, for example, osteomalacia, rickets and skeletal deformities.
Seizures or breathing difficulties occur, which are two factors that represent complications in hypoparathyroidism.
Among the factors that can increase the risk of suffering from hypoparathyroidism include:
- Undergo neck surgery that involves the thyroid.
- Possess genetic predisposition to hypoparathyroidism.
- Suffering from certain autoimmune or endocrine disorders, such as Addison’s disease, which induces the adrenal glands to reduce the amount of hormones they produce, significantly.
The diagnosis that is made in hypoparathyroidism is based on low levels of calcium in the blood.
The values of parathyroid hormone and phosphorus will vary depending on the cause of hypoparathyroidism.
In the case of primary hypoparathyroidism, blood calcium has low levels and phosphorus levels high, and parathyroid hormone is absent or very low.
In the case of a magnesium deficiency, the levels of calcium and phosphorus in the blood are low and the levels of the parathyroid hormone are low or absent.
When pseudohypoparathyroidism occurs there is very little calcium and very little phosphorus in the blood.
Parathyroid hormone is high, in this case, hypophosphatemia is more accentuated than hypocalcemia because there is a greater secretion of parathyroid hormone.
Presenting a partial effectiveness to elevate the calcium in the blood, and favoring the excretion of phosphorus in the kidney.
If there is a suspicion that the cause of hypoparathyroidism is due to a vitamin D deficiency, its blood values should be analyzed, which will be low in most cases.
Urine tests also reveal variations in phosphorus and calcium values.
The clinical history:
The physical examination and the interrogation of the patient will help to discover the origin of the hypoparathyroidism and to request studies for the differential diagnosis.
For example, nutritional deficiency, kidney failure, intestinal disorders, surgical neck surgery, history of a seizure disorder, developmental defects, especially in childhood and adolescence.
Rickets and various neuromuscular syndromes and deformities are also observed.
In the case of primary hypoparathyroidism techniques are used to detect the functioning of the parathyroid glands or the partial or total lack thereof.
These include ultrasound, computed tomography, magnetic resonance of the neck, as well as scintigraphy with the help of technetium isotopes such as 99Tc, which allows us to know if these glands are working or not.
Other techniques such as bone density of the lumbar and hip spine can be indicated to observe the repercussions of hypoparathyroidism at bone level.
Hypoparathyroidism can lead to various complications.
These complications are due to low calcium levels, which are likely to improve with treatment:
- Tetany , spasms and cramps, when these spasms occur at the level of the throat, can interfere with breathing and create an emergency.
- Paresthesias or tingling
- Loss of consciousness with epilepsy.
- Malformation in the teeth.
- Alteration of renal functions.
- Arrhythmias, fainting and heart failure .
With diagnosis and proper treatment, they can be prevented, but once they occur, they will not improve.
- The delays in growth.
- The slow mental development in children.
- Calcium deposits in the brain.
- The appearance of cataracts.
The main objective of the treatment is to normalize the levels of calcium and phosphorus in the body, relieving the symptoms.
- Oral administration of calcium supplements may increase calcium levels in the blood, but in high doses, they can cause gastrointestinal side effects such as constipation.
- Administration of Vitamin D, high doses of vitamin D, can help the body absorb calcium and eliminate phosphorus.
- Parathyroid hormone (Natpara), this injection is administered 24 hours for the treatment of low calcium levels caused by hyperparathyroidism.
It is advisable to make a diet based on:
- Calcium: With the consumption of dairy products, green leafy vegetables and foods that are made with added calcium, such as orange juice and breakfast cereals.
- Low phosphorus content: Avoid gaseous drinks, those containing phosphoric acid, restricting the consumption of hard cheeses, meats and whole grains.
For an immediate relief of symptoms, calcium is recommended by intravenous infusion, continuing with a calcium and vitamin D oral treatment.
The respective blood tests must be done regularly to control calcium and phosphorus levels.
Because hypoparathyroidism is a chronic disorder, treatment is usually lifelong, doses of calcium supplements will be adjusted according to what calcium levels reflect.