The most severe (but fortunately, very rare) complication of hypothyroidism is hypothyroid or myxedematous coma . The basis of its pathogenesis is inhibition of the respiratory center, a progressive decrease in cardiac output, tissue hypoxia and a decrease in the function of the adrenal cortex.
As a rule, hypothyroid coma develops in untreated or improperly treated patients, more often in elderly women (60-80 years) in the cold season, following various stressful situations. Hypothyroidism can be provoked by infections, such as influenza or pneumonia, intercurrent diseases (stroke, myocardial infarction), hypothermia, bleeding, hypoxia, hypoglycemia, trauma, and drugs (tranquilizers, barbiturates, drugs, anesthetics).
Along with the clinical manifestations of hypothyroidism described above, it is characteristic of developing coma:
• a significant decrease in body temperature (sometimes up to 24? С);
• increasing inhibition of the central nervous system (sopor and coma proper), complete suppression of tendon reflexes;
• severe bradycardia and a drop in blood pressure;
• Oliguria and anuria (caused by a sharp hemodynamic disturbance in the kidneys and the development of the syndrome of inadequate vasopressin production; accompanied by hypervolemia and hyponatremia, metabolic acidosis);
• hypoventilation with hypercapnia, respiratory acidosis;
• dynamic intestinal obstruction (a consequence of a sharp atony of the smooth muscles of the intestine);
• heart failure.
Mortality in hypothyroid coma reaches 80%. Death usually comes from increasing cardiovascular and respiratory failure.