12 Questions
What is the primary cause of cretinism?
Congenital insufficiency of thyroid function
Which type of hypothyroidism is characterized by hypersecretion of TSH and a decrease in T4 levels?
Manifest primary hypothyroidism
What is the main drug used in the treatment of hypothyroidism?
Levothyroxine sodium
What levels would be observed in a patient with secondary hypothyroidism?
High TSH and low T4
How is the starting daily dose of levothyroxine sodium determined for the elderly?
12.5 mcg per day
What confirms autoimmune thyroiditis as the root cause of hypothyroidism?
Antibodies to thyroglobulin and thyroid peroxidase
What is the recommended daily intake of thyroxine during pregnancy?
1.9 mcg/kg per day
What is the recommended plasma TSH concentration threshold for initiating replacement therapy in subclinical hypothyroidism?
>10 mU/l
What is the recommended method for monitoring replacement therapy in primary hypothyroidism?
Monitoring TSH levels
Which of the following is NOT a risk factor for developing hypothyroid coma?
Warm climate
What is the recommended method for monitoring replacement therapy in central hypothyroidism?
Monitoring T4 levels
Which of the following is a potential trigger for hypothyroid coma?
Barbiturate therapy
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
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.
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