On what basis can a thyrotoxic crisis be diagnosed?

Thyrotoxicosis is a life-threatening syndrome that manifests itself in patients with diffuse toxic goiter. The severity of thyrotoxicosis does not affect the likelihood of developing a thyrotoxic crisis. Therefore, it is impossible to suspect the likelihood of developing a thyrotoxic crisis and to foresee it.

Causes and factors of thyrotoxic crisis

The most common cause of thyrotoxic crisis – strumectomy and radioactive iodine therapy. The crisis is the result of the release of hormones during surgical procedures, combined with other effects of stress during surgery.

Thyrotoxic crisis development factors:

• Surgery or trauma for a concomitant disease.
• Emotional stress, mental trauma.
• Development of the infectious process.
• Iodine loading of the body (injection of contrast agents through a vein in order to carry out an X-ray examination).
• Intensive and rough palpation of the thyroid gland.
• Radiation therapy.
• Hypoglycemia and ketoacidosis on the background of diabetes mellitus.
• Impaired blood supply to the brain tissue.
• Pulmonary embolism.

Radioactive iodine can cause a thyrotoxic crisis when taken without prior elimination of thyrotoxicosis.

Mechanism of development of thyrotoxic crisis. Flow phases

There are 3 links in the mechanism of development of thyrotoxic crisis.

1. Hyperthyroidism associated with various factors:

- increase in the level of thyroid hormones as the main factor in the development of a crisis;

- absolute and relative increase in free T4 levels after a decrease in the binding capacity of plasma proteins.

2. Relative adrenal insufficiency.
3. Increased activity of the sympathoadrenal system.

During the thyrotoxic crisis, 2 phases are distinguished:

• Subacute - the period from the moment the first signs appear to the loss of consciousness.
• Acute (coma) develops 1-2 days after the unfavorable course of the subacute phase.

Possible death due to acute heart failure, acute adrenal insufficiency and liver failure.

Reaction of systems to thyrotoxic crisis. Crisis Symptoms

Thyrotoxic crisis is characterized by a very rapid onset and acute course, especially if the crisis occurs after trauma or surgery on the thyroid gland. But the crisis against the background of taking radioactive iodine begins more slowly and is not so acute.

Objective signs of the onset of a thyroid crisis:

• CNS lesions – metabolic encephalopathy is observed, which manifests itself in mood lability, feelings of anxiety, confusion, possibly the development of psychosis and coma.
• Gastro – intestinal manifestations – liver enlargement and diffuse pains in the abdomen. The liver is affected against the background of CHF and congestion with it. If jaundice occurs, emergency treatment should be started immediately, as this is a poor prognostic sign.
• Increased sweating with hyperthermia without evidence of infection – the main key in the diagnosis of a thyrotoxic crisis and a direct indication for the start of emergency therapy.
• Losses of the heart – vascular system – against the background of sinus tachycardia and atrial fibrillation, signs of CHF may appear even in young people, which is regarded as a newly diagnosed pathology of the cardiovascular system.

 At the beginning of a crisis state, systolic arterial hypertension with high pulse pressure is observed. Against the background of vomiting, diarrhea and increased sweating, the volume of circulating blood decreases, which leads to the development of postural hypotension and collapse. This is one of the causes of death from a thyrotoxic crisis.

"Behavior" thyroid hormones in thyroid storm. Diagnostics

Before starting therapy, blood tests for biochemistry, a complete blood count and a blood test for thyroid hormones are taken.

In the general blood test, only leukocytosis is detected. In the biochemical analysis of blood, hyperglycemia is observed without the presence of diabetes mellitus. This is the result of increased activity of glycogenolysis. There is also severe hypocholesterolemia, a decrease in the prothrombin index and fibrinogen levels, hypoproteinemia, hypercalcemia. The activity of transaminases and alkaline phosphatase increases.

In the hormonal background, the levels of thyroid hormones in the blood, namely T3 and T4, are increased. In some patients, the level of T3 may be within the normal range, which provokes the development of low T3 syndrome.

Treatment of thyrotoxic crisis. Goals and methods of crisis correction

Emergency therapy should begin immediately after the diagnosis of thyroid crisis is established and consists in methods of suppressing the synthesis of new hormones, reducing hormone secretion and peripheral conversion of thyroxine and triiodothyronine.

Methods of treatment of thyroid storm:

• To block the synthesis of thyroid hormones, thiamazole or propylthiouracil is used.
• To reduce the activity of colloid proteolysis and prevent the release of T4 and T3 into the blood, lithium carbonate or inorganic iodine is prescribed, but only after the appointment of antithyroid drugs. You can use iodine preparations inside.
• Plasmapheresis or peritoneal dialysis is used to lower the level of thyroid hormones in the blood. B-blockers are used as symptomatic therapy to reduce the activity of the sympathoadrenal system. Glucocorticosteroids are used to relieve adrenal insufficiency.
• Replenishment of fluid loss and normalization of body temperature are symptomatic therapy, the purpose of which is to eliminate hypoxia, dehydration and hyperthermia during a thyrotoxic crisis.

Against the background of intensive therapy, the condition improves throughout the day. In order to avoid a thyrotoxic crisis, it is necessary to detect and treat thyroid pathologies in time, to refuse planned surgical interventions for patients with decompensated thyrotoxicosis, to carry out surgical treatment of the thyroid gland only after the maximum course of drug therapy, and also treatment with radioactive iodine should be carried out against the background of compensation for thyrotoxicosis.