Hypoparathyroidism (tetany)

A disease characterized by decreased function of the parathyroid glands, increased neuromuscular excitability and convulsive syndrome.

Etiology. Congenital underdevelopment or absence of the parathyroid glands, their removal or damage during surgery, their damage due to infections, intoxications, autoimmune disorders, and decreased tissue sensitivity to the action of parathyroid hormone play a role.

Pathogenesis. Insufficient release of parathyroid hormone, leading to disturbances in calcium-phosphorus homeostasis (hypocalcemia and hyperphosphatemia). Neuromuscular excitability increases, and a tendency to develop convulsive syndrome appears.

Symptoms, course. An attack of convulsions is usually preceded by a feeling of numbness, crawling in the area of ​​the upper lip, fingers and toes, coldness of the extremities, and a feeling of stiffness. Then painful tonic and clonic spasms of individual muscle groups develop: limbs, face, torso. Cramps are observed mainly in the flexor muscles, so the hand takes the characteristic position of the “obstetrician’s hand.”

With tetany of the flexor muscles of the lower extremities, the foot bends inward, the toes curl toward the sole (“cauda equina”). Facial muscle spasms are accompanied by trismus, the formation of a “fish mouth”. The spread of cramps to the neck muscles can cause laryngospasm, accompanied by shortness of breath, cyanosis, and sometimes asphyxia.

Pylorospasm with vomiting, nausea, and acidosis may develop; spasms of the muscles of the intestines and bladder. Attacks of tetany are provoked by various stimuli: painful, mechanical, thermal, hyperventilation. Tapping on the trunk of the facial nerve near the external auditory canal causes contraction of the muscles of the forehead, upper eyelid, mouth (Chvostek's symptom), tapping along the upper branch of the facial nerve at the outer edge of the orbit leads to contraction of the orbicularis muscle of the eyelid (Weiss' symptom); pulling the shoulder with a tourniquet - to the characteristic position of the hand - “obstetrician’s hand” (Trousseau’s symptom).

With a long course of the disease in the interictal period, patients are concerned about sweating, blurred vision due to impaired accommodation, ringing in the ears, and decreased hearing. Hypocalcemic cataracts, brittle nails, fragility and dental caries develop. Mental changes are observed: decreased intelligence, memory impairment, neuroses.

The calcium content in the blood is reduced, especially its ionized fraction; A relationship has been established between the severity of tetany and the degree of decrease in calcium levels in the blood. The phosphorus content in the blood is higher than normal, the excretion of calcium and phosphorus in the urine is reduced. The level of parathyroid hormone in the blood serum is reduced.

Treatment. To relieve an attack of tetany, 20-50 ml of a 10% solution of calcium chloride or calcium gluconate is administered intravenously. To prevent attacks, calcium preparations are prescribed orally (gluconate, lactate, glycerophosphate, combined preparations of calcium salts - for example, calcium forte 1-2 g per day), a diet rich in calcium is recommended (milk, cheese, cabbage, lettuce, radishes, apricots, strawberries, lemons), use vitamin D preparations (alfacalcidol, calcitriol, etc.).