Cretinism: Causes and Characteristics

Study Notes

Thyroid Hormone Replacement Therapy

During pregnancy, the daily dose of thyroxine is 1.9 mcg/kg, with a 45% increase in need.
After removal of the thyroid gland, the daily dose is 2.3 mcg/kg.

Indications for Replacement Therapy

Plasma TSH concentration >10 mU/l
Symptoms of hypothyroidism
Increase in atherogenic fractions of lipoproteins and/or cholesterol
High titers of antithyroid antibodies

Replacement Therapy

For primary hypothyroidism, therapy is carried out under TSH control (after 6-8 weeks, then 1 time per year)
For central hypothyroidism, therapy is carried out under T4 control
Thyroid hormones should be taken at least 30 minutes before a meal
Duration of therapy is lifelong (except for transient forms)

Hypothyroid Coma

Can occur in any form of hypothyroidism
More common in elderly patients with undiagnosed hypothyroidism, severe comorbidities, and lack of care
Provoking factors: hypothermia, barbiturate therapy, anesthesia, and intercurrent diseases

Cretinism

A dysfunction of the thyroid gland leading to delayed physical and mental development
Causes: congenital insufficiency of thyroid function or its absence, or lack of iodine or thyroid hormones during childhood growth
Examples: entire villages inhabited only by cretins in Austria, Germany, and Switzerland

Diagnosis of Hypothyroidism

Latent (subclinical) primary hypothyroidism: high TSH levels with normal T4
Manifest primary hypothyroidism: hypersecretion of TSH and decreased T4 levels
Antibodies to thyroglobulin and thyroid peroxidase confirm autoimmune thyroiditis as the root cause of hypothyroidism
Secondary hypothyroidism: TSH and T4 are reduced

Treatment of Hypothyroidism

Main drug: levothyroxine sodium (L-thyroxine)
Goal of replacement therapy: achieve and maintain euthyroid state throughout life, with TSH levels between 0.5-2.0 mIU/l
Dosage:
- Up to 50 years: 1.6-1.8 mcg/kg per day
- Obese patients: dose calculation based on ideal weight
- Elderly patients: start with 12.5 mcg per day, or 6.25 mcg per day with concomitant cardiac pathology
- Concomitant severe diseases: daily dose of 0.9 mcg/kg
- Average daily dose: 150 mcg/day for men, 100 mcg/day for women

Description

Learn about cretinism, a dysfunction of the thyroid gland that leads to delayed physical and mental development. Understand the causes such as congenital insufficiency of thyroid function or iodine deficiency, and explore different types of cretinism like neurological and myxedematous cretinism.