Thyroid disorders

Clinical syndromes and systemic impact

The interview and physical examination of a patient with any thyroid disorder are always based on a systemic assessment. The physician must examine not only the local status of the gland itself, but also the condition of all organs and systems.

Virtually the entire spectrum of detected symptoms is explained by either an excess or a critical shortage of the effects of iodothyronines ($T_3$ and $T_4$ hormones) on target cells. These hormones play a universal role in the body: they control thermogenesis and regulate basal metabolism in virtually all tissues. That is why the clinical picture of the two main functional states — hypothyroidism and hyperthyroidism — is absolutely polar, "mirror-like."

Comorbidity: connection with gastric pathology

Thyroid diseases are often autoimmune in nature and demonstrate a high frequency of comorbidity with other endocrinopathies and systemic disorders. In particular, such pathologies as thyrotoxicosis, hypothyroidism, and Hashimoto's goiter are closely linked to the development of pernicious anemia.

Pernicious anemia is based on impaired synthesis of intrinsic factor due to autoimmune gastric pathology (mucosal atrophy and achlorhydria). Evidence of a common autoimmune genesis of these conditions includes:

• Detection of specific autoantibodies to gastric parietal cells (found in 90% of patients with pernicious anemia, whereas in conventional atrophic gastritis — in only 10%).
• Presence of antibodies directly blocking intrinsic factor or the already formed "intrinsic factor + vitamin $B_{12}$" complex.
• Detection of cross-reactive immunological markers, such as antithyroglobulin antibodies and rheumatoid factor.
• Positive effect of glucocorticoid therapy, demonstrating regression of symptoms under the influence of immunosuppression.

Pericardial involvement in thyroid disorders

Changes in the functional status of the thyroid gland can provoke specific pericardial lesions.

In hyperthyroidism (thyrotoxicosis):

• Pericardial effusion is generally rarely detected.
• Hydropericardium may develop in severe thyrotoxicosis accompanied by symptoms of congestive chronic heart failure (CHF) and atrial fibrillation.
• Hemopericardium has been described in patients with Graves' disease forced to receive anticoagulant therapy due to concomitant atrial fibrillation.
• Cardiac tamponade is encountered in extremely rare cases.

In hypothyroidism: If the disease is complicated by recurrent pericarditis, the patient requires strict monitoring of vitamin D levels. The combination of uncompensated hypothyroidism and systemic glucocorticoid intake significantly increases the risk of developing severe osteoporosis.

Principles of pericarditis therapy

The primary and foremost goal of treating pericarditis in any thyroid dysfunction is achieving a stable euthyroid state.

Drug therapy uses:

• Antithyroid drugs;
• Acetylsalicylic acid;
• Nonsteroidal anti-inflammatory drugs (NSAIDs);
• Colchicine (autumn crocus seed extract);
• Glucocorticoids.

Pharmacokinetic features: if the patient has hyperthyroidism, the expression of P-glycoprotein increases in the body. This directly affects drug metabolism, which may require a significant increase in the dose of administered drugs (in particular, colchicine).

Class and exam questions

What else to study on this topic

• Mechanisms of thyroid hormone influence on cellular thermogenesis and metabolism
• Pathogenesis of pernicious anemia: the role of achlorhydria and intrinsic factor
• Features of the development of hydropericardium in congestive heart failure
• The effect of P-glycoprotein on drug pharmacokinetics
• Technique of local examination and palpation of the thyroid gland

Other topics in the "Additional Topics" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.