Thyroid Flashcards
What is the most common cause of congenital hypothyroidism worldwide?
Iodine deficiency (endemic goiter)
What is the most common cause of permanent congenital hypothyroidism in iodine-sufficient areas?
Thyroid gland dysgenesis (80-85% of cases)
What is the typical clinical presentation of congenital hypothyroidism in infants?
Large posterior fontanel, macroglossia, prolonged jaundice, umbilical hernia, constipation, hypotonia, hypothermia, lethargy
What is the first-line treatment for congenital hypothyroidism?
Levothyroxine (10-15 µg/kg/day)
What is the goal of levothyroxine therapy in congenital hypothyroidism?
To maintain serum FT4 in the upper half of the normal range
What is the incidence of congenital hypothyroidism?
1/4000 to 1/2000 worldwide
What is the role of TRH in fetal development?
TRH can be detected by 10-14 weeks of gestation and is part of the hypothalamic-pituitary-thyroid axis
What is the significance of a TSH level >40 mIU/L in a newborn?
It is concerning for congenital hypothyroidism
What is the most common cause of hypothyroidism in children and adults?
Hashimoto thyroiditis (autoimmune thyroiditis)
What is the female-to-male ratio in Hashimoto thyroiditis?
0.16736111111111107
What is the typical presentation of Hashimoto thyroiditis?
Goiter (70% of cases), often asymptomatic, may present with signs of hypothyroidism
What is the treatment for Hashimoto thyroiditis?
Levothyroxine therapy, with the goal of keeping TSH between 1 and 3 µIU/mL
What is the most common cause of hyperthyroidism in the pediatric population?
Graves disease
What is the peak incidence age group for Graves disease?
11-15 years old
What is the female-to-male ratio in Graves disease?
0.2090277777777778
What is the initial treatment for Graves disease?
Antithyroid drugs (e.g., methimazole)
What is the role of radioactive iodine (RAI) in Graves disease?
It is used for permanent therapy if remission is not achieved with antithyroid drugs
What is subacute thyroiditis?
A self-limited inflammation of the thyroid, often following an upper respiratory tract infection
What is the typical presentation of subacute thyroiditis?
Fever, pain referred to the jaw, tender thyroid gland, and symptoms of hyperthyroidism
What is the treatment for subacute thyroiditis?
Anti-inflammatory medications to control pain; transient hypothyroidism may occur
What is neonatal thyrotoxicosis?
Hyperthyroidism in neonates due to transplacental delivery of TSI antibodies from a mother with Graves disease
What is the treatment for neonatal thyrotoxicosis?
Self-limited; may require methimazole and beta-blockers to control symptoms
What is the most common benign thyroid nodule in children?
Follicular adenoma
What is the most common type of thyroid cancer in children?
Papillary carcinoma (90% of childhood thyroid cancers)
What is the diagnostic workup for thyroid nodules?
Thyroid function tests, neck ultrasound, fine-needle aspiration (FNA)
What is the role of iodine-123 in thyroid imaging?
It is used to determine thyroid gland location and uptake
What is the typical presentation of central hypothyroidism?
Signs of hypothyroidism (dry skin, constipation, cold intolerance) with normal/low TSH
What is the treatment for central hypothyroidism?
Levothyroxine replacement therapy, aiming for normalization of free T4
What is the most common cause of central hypothyroidism in children?
Congenital TSH deficiency (often associated with other pituitary hormone deficiencies)
What is the typical presentation of Hashitoxicosis?
Transient hyperthyroidism due to release of stored thyroid hormone from Hashimoto thyroiditis
What is the treatment for Hashitoxicosis?
Beta-blockers to control symptoms; it is self-limited and evolves into permanent hypothyroidism
What is the role of TPO antibodies in Hashimoto thyroiditis?
They are present in >90% of cases and are a marker of autoimmune thyroiditis
What is the typical ultrasound finding in Hashimoto thyroiditis?
Enlarged thyroid gland with heterogeneous echogenicity
What is the typical presentation of subclinical hypothyroidism?
Elevated TSH with normal thyroid hormone levels, often asymptomatic
What is the treatment for subclinical hypothyroidism?
Levothyroxine is not recommended if TSH <10 and no goiter or antibodies; consider treatment if TSH >10
What is the typical presentation of Graves disease in children?
Goiter, tachycardia, weight loss, anxiety, tremors, and growth acceleration
What is the role of thyroid receptor antibodies in Graves disease?
They mimic TSH action, leading to hyperthyroidism
What is the typical presentation of neonatal thyrotoxicosis?
Irritability, tachycardia, poor feeding, failure to thrive, and craniosynostosis
What is the typical presentation of thyroid-related neck mass in children?
Solitary thyroid nodule, often cystic and benign (70-80% of cases)
What is the typical presentation of medullary thyroid cancer?
Associated with MEN 2A or 2B, elevated calcitonin levels, and RET proto-oncogene mutations
What is the treatment for medullary thyroid cancer?
Surgical resection, often with prophylactic thyroidectomy in familial cases
What is the typical presentation of congenital hypothyroidism in older children?
Poor linear growth, developmental delay, delayed tooth development, and hearing loss
What is the role of newborn screening in congenital hypothyroidism?
It screens for elevated TSH levels, typically collected at 24-72 hours of life
What is the typical presentation of transient hypothyroidism in neonates?
Caused by maternal antibodies or medications, resolves without long-term treatment
What is the typical presentation of dyshormonogenesis?
Autosomal recessive disorder causing goiter due to enzyme defects in thyroid hormone synthesis
What is the typical presentation of thyroid hormone resistance?
Elevated thyroid hormone levels with normal or elevated TSH, often asymptomatic
What is the typical presentation of thyroid storm?
Severe hyperthyroidism with fever, tachycardia, heart failure, and altered mental status
What is the treatment for thyroid storm?
Beta-blockers, antithyroid drugs, iodine, and corticosteroids
What is the typical presentation of thyroiditis?
Painful or painless thyroid inflammation, often with transient hyperthyroidism followed by hypothyroidism
What is the typical presentation of thyroid cancer in children?
Solitary thyroid nodule, rapid growth, hoarseness, or lymph node involvement
