What is Hypoparathyroidism?
Hypoparathyroidism is a disease in which, for some reason, the hormone parathyroid glands (parathyrin) is not produced in the body or the sensitivity of tissue receptors to this hormone is impaired, resulting in decreased parathyroid hormone function. This condition is accompanied by attacks of tonic seizures.
Causes of Hypoparathyroidism
The cause of hypoparathyroidism is inflammatory processes in the parathyroid glands, hemorrhages in the parathyroid glands as a result of traumatic injuries of the neck, strychnine, lead poisoning, carbon monoxide, ergot, vitamin D hypovitaminosis, during pregnancy and lactation, when calcium absorption in the intestines is disturbed, when exposed to radiation.
Metastases of malignant tumors to the parathyroid glands can lead to hypoparathyroidism. Sometimes a decrease in the function of the parathyroid glands can be congenital in case of underdevelopment of the parathyroid glands in the prenatal period of fetal development.
Hypoparathyrosis develops in various autoimmune processes:
- primary hypothyroidism
- chronic adrenal cortex insufficiency
- polyendocrine autoimmune syndrome
- familial endocrinopathy.
But most often, the cause of hypoparathyroidism is surgery on the thyroid gland or other organs of the neck, when the parathyroid glands are accidentally damaged. Especially often this happens with the total (complete) removal of the thyroid gland due to thyroid cancer.
Pathogenesis during Hypoparathyroidism
A deficiency of parathyroid hormone leads to an increase in the level of phosphorus in the blood, as well as to hypocalcemia, due to a decrease in calcium absorption in the intestine, a decrease in its mobilization from the bones, and insufficient reabsorption in the renal tubules, which is partly due to a decrease in kidney synthesis of 1.25 (OH) 2D3. whose production is controlled by parathyroid hormone. Hypocalcemia and hyperphosphatemia lead to a universal violation of the permeability of cell membranes and to an increase in neuromuscular excitability and convulsive readiness, autonomic lability, and also to the deposition of calcium salts in the internal organs and walls of large vessels.
Symptoms of Hypoparathyroidism
The insufficiency of parathyroid hormone (parathyrin) or a decrease in the sensitivity of receptors to it leads to a violation of the exchange of calcium and phosphorus. The absorption of calcium in the intestine is reduced, the excretion of calcium from bone tissue is reduced and the amount of calcium in the blood decreases. At the same time, the amount of phosphate in the blood rises. A decrease in the amount of calcium leads to an increase in neuromuscular arousal and tonic convulsions develop.
With a long course of the process, hypotrophy and muscle atrophy can develop. At the beginning of the illness, the patient has complaints of numbness and chills of the limbs, a sensation of “crawling”, tingling, a rush of heat to the arms or legs, a sensation of “spasm” of the muscles. All these manifestations are enhanced by exposure to overheating, cold, physical exertion, with infectious diseases, mental stress.
Over time, painful cramps appear in symmetrical muscle groups. Most often, characteristic convulsions appear in the hands, the so-called “obstetrician’s arm.” On the lower extremities, cramps appear in the form of a horse’s foot, when the fingers are pressed to the back of the foot, the patient cannot stand on the entire foot, this is accompanied by tension of the muscles of the leg and thigh.
If the seizures spread to the face, a “fish mouth” occurs due to tension in the muscles around the mouth, a “sardonic smile”, and when the seizures spread to the masticatory muscles, painful tension can occur, leading to convulsive jaw compression (trismus). The muscles of the abdomen and chest are less likely to suffer, but with prolonged convulsive tension, respiratory failure occurs, which can be life threatening. The severity of the condition usually depends on the level of calcium in the blood.
Light, moderate and severe degrees of hypocalcemia (a decrease in the amount of calcium in the blood) are distinguished. If hypoparathyroidism is difficult and prolonged, changes in the central nervous system (irritability, memory impairment, depression) join. Intracranial pressure rises and there is a headache, discomfort in the eyes when looking at the light. Sometimes this is accompanied by the occurrence of convulsive seizures similar to an epileptic seizure. From the autonomic nervous system, disorders are manifested by heart palpitations, sweating, abdominal pain, diarrhea.
Chronic hypoparathyroidism is manifested by changes in the skin:
- dry and peeling skin
- fragility of nails
- hair loss
- tooth decay
- characteristic changes in tooth enamel.
Inflammatory processes appear in the mucous membrane of the eyes (conjunctivitis, keratitis, blepharitis), cataracts often develop.
Diagnosis of Hypoparathyroidism
Acute and chronic forms of hypoparathyroidism are called explicit, since in both cases, patients will experience symptoms of this disease, only expressed to varying degrees.
Diagnosis of obvious forms is simple, because it is based on the presence of characteristic symptoms (primarily convulsions).
The diagnosis is based on the following data:
- an indication in the anamnesis (collection of data on the patient’s disease from the patient’s words and records in the outpatient card) for surgery on the thyroid gland, parathyroid glands, treatment with radioactive iodine;
- bouts of seizures (according to the patient);
- a decrease in calcium in the blood and urine, which is detected by a laboratory study;
- increased levels of phosphate in the blood and a decrease in urine;
- decreased levels of parathyroid hormone in the blood;
- change in the electrocardiogram of the heart;
- cataract (clouding of the lens leading to visual impairment).
The latent form of hypoparathyroidism is extremely difficult to distinguish, since there are no characteristic symptoms, therefore, special tests or symptoms are used for diagnosis.
- Symptom Khvosteks – contraction of the muscles of the face when tapping in front of the external auditory meatus (this is the exit site of the facial nerve).
- Symptom of Trousseau – cramps in the area of the hand 2-3 minutes after pulling the shoulder with a tourniquet or cuff of a tonometer (an apparatus for measuring blood pressure).
- Weiss’s symptom is a contraction of the muscles of the eyelids and frontal muscle when striking at the outer edge of the orbit.
- Hoffmann’s symptom is the appearance of paresthesia when pressure is applied at the inner edge of the eyebrow (nerve branching site).
- Symptom of Schlesinger – cramps in the extensor muscles of the thigh and foot with rapid flexion in the hip stand with the straightened knee joint.
- Erb’s symptom is increased electroexcitation of the nerves of the extremities during irritation with a weak current, which is expressed in convulsions.
Treatment of an acute attack of hypoparathyroidism is carried out in a hospital. A solution of calcium glucanate or calcitriol preparations is administered intravenously, sedatives (phenobarbital, relanium) and antispasmodics (no-shpa, papaverine) are prescribed.
For the treatment of chronic paratyrosis, diet is of great importance. It is recommended to include foods rich in calcium and poor in phosphorus, as well as foods high in vitamin D (egg yolks, fish liver, rosehips, cauliflower). Since phosphorus is found in almost all vital products, aluminum hydroxide, which binds phosphorus in the intestine, is prescribed to reduce its absorption in the intestine. Various calcium preparations and vitamin D preparations are also used.
Recently, surgical treatment of hypoparathyroidism is used – transplantation of the parathyroid glands.
The prognosis for life is favorable. It is necessary to observe an endocrinologist to control the compensation of the disease and correct therapy 1 p / 3-4 months; 1 r / 6 month examination by an oculist is necessary (the possibility of development and progression of cataracts); X-ray control or computed tomography of the brain according to clinical indications (calcification of the basal ganglia).