Hypoparathyroidism is a disease that develops due to a lack of parathyroid hormone secreted by the parathyroid glands, or a violation of the receptor tissue sensitivity to it. A decrease in the functional activity of the parathyroid glands of various genesis is observed in 0.3—0.4% of the population and can occur at any age, leading to a violation of calcium and phosphorus metabolism. There are congenital, postoperative, post-traumatic, autoimmune and idiopathic hypoparathyroidism. During the diagnosis of hypoparathyroidism, it is important to determine the content of parathyroid hormone, Ca and P in the blood, to detect osteosclerosis during X-ray examination and densitometry.
ICD 10
E20 Hypoparathyroidism
Causes
Parathyroid hormone, together with thyroid hormone calcitonin and vitamin D, is responsible for the regulation of phosphorus-calcium metabolism in the body. Its deficiency causes a decrease in blood calcium levels and an increased content of phosphates. As a result, the mineral balance is disturbed (the balance between K, Na, Mg ions), the permeability of cell membranes, which is manifested by increased neuromuscular excitability and convulsions. Hypocalcemia and hyperphosphatemia contribute to the deposition of calcium salts in internal organs and on the walls of blood vessels.
The development of hypoparathyroidism is often associated with thyroid diseases, which is explained by their close anatomical location and close functional relationship. Hypoparathyroidism can develop as a result of:
- surgical intervention on the thyroid gland or other organs of the neck with damage to the parathyroid glands. The so-called postoperative hypoparathyroidism usually occurs after complete removal of the thyroid gland (thyroidectomy) with an oncological diagnosis;
- hemorrhages in the parathyroid glands with neck injuries;
- inflammatory processes in the parathyroid glands;
- tumor metastases to the parathyroid glands and neck area;
- congenital pathology (intrauterine underdevelopment of the parathyroid glands) – occurs with Di Giorgi syndrome, characterized by a violation of the development of the parathyroid glands, thymus aplasia and congenital heart defects;
- exposure to radiation (in the treatment of toxic goiter with radioactive iodine);
- endocrine disorders (primary hypothyroidism, chronic adrenal insufficiency);
- autoimmune syndrome, systemic diseases (hemochromatosis and amyloidosis).
Classification
Modern endocrinology distinguishes the following forms of hypoparathyroidism due to the nature of the course of the disease:
- acute – the condition is difficult to compensate, severe seizures often occur;
- chronic – infrequent seizures are provoked by infections, physical exertion, nervous overstrain, menstruation, psychological trauma). Exacerbations of hypoparathyroidism usually occur in spring and autumn. Adequate treatment allows for long-term remission.
- latent (hidden) – there are no external manifestations, it is detected only during a special examination.
Taking into account the cause , hypoparathyroidism is isolated:
- postoperative (after surgical interventions on the thyroid and parathyroid glands);
- post-traumatic (after radiation and infectious exposure, hemorrhages, etc.);
- idiopathic, autoimmune;
- congenital (as a result of the absence or underdevelopment of the parathyroid glands).
Hypoparathyroidism symptoms
The main clinical manifestation of hypoparathyroidism is convulsive (tetanic) syndrome. Increased neuromuscular excitability with insufficient secretion of parathyroid hormone leads to seizures – strong muscle contractions accompanied by pain.
An attack of convulsions may be preceded by a feeling of numbness, stiffness of the muscles, “crawling goosebumps” over the upper lip, on the fingers and toes, tingling, cold limbs. After the precursors, convulsions of individual muscle groups appear, symmetrically located on both sides (usually the muscles of the arms, then the muscles of the legs). Sometimes the muscles of the face are affected, less often the muscles of the body and internal organs.
Depending on the cramped muscles, characteristic manifestations develop on the part of the relevant organs.
Convulsive syndrome in hypoparathyroidism is manifested by muscle spasm:
- upper and lower extremities (flexor muscles are mainly affected). With convulsions in the hands – the upper limb is bent at the elbow and wrist joints and pressed against the trunk;
- faces (characterized by clenched jaws, drooping corners of the mouth, knitted eyebrows, half-closed eyelids);
- heart vessels (sharp pain is felt);
- torso (the trunk is extended backwards);
- neck, intercostal muscles, diaphragm and abdominal muscles (leads to difficulty breathing, shortness of breath, bronchial spasm);
- esophagus, stomach, intestines (there is a violation of swallowing, constipation, intestinal colic);
- bladder with the manifestation of anuria (absence of urination).
With hypoparathyroidism, seizures are painful, with a mild form of the disease they occur 1-2 times a week, can last for minutes; with a severe form they occur repeatedly during the day and last for several hours. They may appear spontaneously, or they may be provoked by any external stimuli (mechanical, painful, thermal, electrical). Muscle spasm may be accompanied by pallor of the skin, pressure drops, palpitations, digestive disorders (vomiting, diarrhea). In severe cases of hypoparathyroidism, patients may lose consciousness.
Vegetative disorders in hypoparathyroidism are manifested by symptoms of increased sweating, dizziness, fainting; ringing, a feeling of “laying” in the ears, hearing loss; visual concentration and twilight vision disorders; pain and heart failure; impaired sensitivity of receptors (auditory – increased sensitivity to harsh sounds, noise, loud music; gustatory – decreased susceptibility to sour and increase to sweet and bitter, violation of adequate perception of ambient temperature – a feeling of cold or heat).
With a long-term low level of Ca in the blood of patients with hypoparathyroidism, mental changes are noted: decreased intelligence, memory, neurosis, emotional lability (depression, melancholy), sleep disorder.
The chronic course of hypoparathyroidism leads to trophic disorders. Peeling, dryness and changes in skin pigmentation, brittle nails, the appearance of vesicles with serous contents on the skin, eczema, fungal diseases are characteristic. There is a violation of hair growth, partial or complete baldness, early graying. The tooth tissue is damaged: in children, the formation of teeth is disrupted, areas of enamel hypoplasia are found; in patients of all age groups, damage to the enamel of teeth, the development of caries. Children also have a lag in growth.
With prolonged hypoparathyroidism, cataracts may develop (clouding of the lens with a decrease in visual acuity and the development of blindness). With the latent course of the disease, muscle spasms can occur with acute infections, intoxication, pregnancy, vitamin deficiency.
Complications
With a sharp decrease in the level of Ca in the blood, a hypocalcemic crisis (tetany) develops. A convulsive attack occurs spontaneously or as a result of external irritation (mechanical, acoustic, hyperventilation). Usually, it begins suddenly, less often with precursor symptoms (the appearance of general weakness, paresthesia in the face and in the fingertips), with rapid twitching of individual muscles, then tonic or clonic convulsions.
With a spasm of the musculature of the hands, the tone of the flexor muscles increases, (the hand takes the position of the “obstetrician’s hand”). With muscle cramps in the legs, the extensor muscles are more tense (flexion of the sole – “horse foot”). There is painfulness of seizures during tetany attacks, but the patient is conscious. A spasm of smooth muscles can manifest as hepatic or renal colic.
The development of bronchospasm and laryngospasm sharply disrupts breathing and poses a danger to the lives of patients with hypoparathyroidism, especially children. Irreversible in hypoparathyroidism are complications caused by prolonged calcium deficiency, such as cataract, calcification of brain tissues and other organs.
Diagnostics
The diagnosis of obvious clinical forms of hypoparathyroidism is based on the results of an external examination of the patient, the presence of a typical anamnesis (operations on the thyroid or parathyroid glands, radiation therapy with radioactive iodine), symptoms of increased neuromuscular excitability (convulsive readiness or attacks of tonic seizures).
Laboratory diagnosis of hypoparathyroidism involves the study of the level of calcium and phosphorus, parathyroid hormone in the blood and urine. With hypoparathyroidism, hyperphosphatemia, hypocalcemia, a decrease in the concentration of parathyroid hormone in the blood serum, hypocalciuria, hypophosphaturia are noted.
On radiographs, osteosclerosis, calcification of rib cartilage is determined, according to the results of densitometry – increased bone density. MRI reveals the deposition of Ca in the internal organs, subcutaneous tissue, ganglia of the brain. To identify hidden forms of hypoparathyroidism, tests are carried out to determine increased convulsive readiness, a test with hyperventilation.
Hypoparathyroidism treatment
Therapy of hypoparathyroidism and prevention of seizures is carried out under the constant supervision of an endocrinologist. A diet rich in calcium, magnesium and poor in phosphorus (dairy products, vegetables, fruits) is prescribed. A sharp restriction or rejection of meat products is necessary during the period of exacerbation of hypoparathyroidism. It is important to take vitamin D2 (ergocalciferol) with food, which is contained in egg yolk, liver, fish oil.
With hypoparathyroidism, calcium preparations (calcium carbonate, calcium gluconate) are prescribed. To increase the absorption of calcium in the intestine, its simultaneous intake with ammonium chloride, gastric juice or diluted hydrochloric acid is mandatory. Compensation of the condition with hypoparathyroidism with calcium monotherapy does not allow to completely normalize its level in the blood, therefore vitamin D preparations (ergocalciferol, alfacalcidol, colecalciferol) are additionally used. Moderate physiotherapeutic ultraviolet irradiation or sunbathing is recommended for patients with chronic hypoparathyroidism to activate the production of vitamin D in their own body.
For the prevention of convulsive syndrome, anticonvulsants and sedatives (luminal, bromides) are prescribed; in the case of a hypocalcemic crisis, a solution of calcium gluconate is administered intravenously.
Forecast
Prognostic data for hypoparathyroidism are favorable. Treatment of hypoparathyroidism and prevention of seizures require constant monitoring by an endocrinologist. Monitoring is carried out in order to assess the compensation of the disease and correct the course of treatment 1 time every 3 months, once every six months an examination by an optometrist is necessary for the possible development of cataracts.
Prevention
In order to prevent hypoparathyroidism during surgical intervention on the thyroid gland, sparing surgical techniques are used in relation to the parathyroid glands. In order to avoid the development of hypoparathyroidism, patients with recurrent toxic goiter are recommended to undergo radiation therapy with radioactive iodine instead of surgery. It is important to prevent postoperative complications (adhesions, infiltrates) that can disrupt the blood supply to the parathyroid glands, as well as early detection of symptoms of increased neuromuscular excitability in patients after surgery on the thyroid gland and timely measures.
To prevent convulsive syndrome and the development of an acute hypocalcemic crisis in hypoparathyroidism, it is necessary to exclude provoking factors, prevent intoxication and infections. Patients with hypoparathyroidism should follow a diet: it should be enriched with calcium and limited to phosphorus, it is necessary to completely abandon meat products, as they cause the development of tetany. In hypoparathyroidism, dispensary monitoring of the content of Ca and P in the blood is carried out.