Ch. 565 & 566 - Hypothyroidism and Thyroiditis Flashcards
T/F Most cases of congenital hypothy is NOT hereditary
T
T/F Most cases of congenital hypothy results from thyroid dysgenesis
T
Cause of congenital hypothy in which goiter is almost always present
Dyshormonogenesis
MC T4 synthetic defect
Thyroid peroxidase defects of organification and coupling
Seen in radioiodine test as marked discharge of thyroid radioactivity when perchlorate or thiocyanate is administered
Thyroid peroxidase defects of organification and coupling
T/F Congenital hypothy can result from fetal exposure to excessive iodides
T
MCC of hypothy worldwide
Iodine deficiency or endemic goiter
T/F Most patients with congenital hypothy are asymptomatic at birth, EVEN IF there is complete agenesis of the thyroid gland
T, due to transplacental passage of moderate amounts of maternal T4
May be the earliest sign of congenital hypothyroidism
Prolongation of physiologic jaundice caused by delayed maturation of glucuronide conjugation
Affected infants cry little, sleep much, have poor appetites, and are generally sluggish
Congenital hypothy
Congenital hypothy T/F: Umbilical hernia is usually present
T
Congenital hypothy T/F: Temperature is subnormal
T
Congenital hypothy T/F: Edema of genital and extremities may be present
T
Congenital hypothy: Type of anemia
Macrocytic, refractory to treatment with hematinics
Congenital hypothy T/F: Majority have associated congenital anomalies
F, 10%
MC congenital anomaly associated with congenital hypothy
Cardiac
Congenital hypothy: Full clinical picture with physical and mental retardation is fully developed when
3-6 months of age
Can serve as initial sign to the early recognition of congenital hypothy
Widely open anterior and posterior fontanels
Hypotonic muscles but affected older children have an athletic appearance because of pseudohypertrophy, particularly of the calf muscles
Congenital hypothyroidism
T/F Congenital hyperthyroidism is primarily a thyroid defect
T, TSH elevated >100mU/L
Serum thyroglobulin level: Infants with thyroid agenesis
Low
Serum thyroglobulin level: Infants with ectopic thyroid glands (thyroid dysgenesis)
Elevated
Management for thyroid dysgenesis
Lifelong treatment with T4
T/F Demonstration of ectopic thyroid tissue is diagnostic of thyroid dysgenesis
T
How often are FT4 and TSH ideally monitored among patients with congenital hypothyroidism
Monthly for the 1st 6 mos, then every 2-3 months until 2 years old
Risks of overtreatment with levothyroxine
1) Craniosynostosis 2) Temperament problems
MCC of acquired hypothyroidism
Chronic lymphocytic thyroidits
Cause of hypothy in Down syndrome
Development of antithyroid antibodies
T/F Majority of children with Down Syndrome have overt or subclinical hypothy
F, 15-20%
T/F Majority of girls with Turner syndrome develop hypothyroidism
F, 15-30%
T/F Risk of subclinical or overt hypothy increases with age in patients with Turner Syndrome
T
Cause of hypothy in patient’s with Turner syndrome
Development of antithyroid antibodies
T/F Removal if ectopic thyroid tissue can cause hypothyroidism
T
T/F Protracted ingestion of medications that contain iodides can cause hypothyroidism
T, usually accompanied bbyb goiter
Medication containing 37% iodine by weight that causes hypothyroidism in about 20% of treated children
Amiodarone
Usually the first clinical manifestation of acquired hypothy
Deceleration of growth
Nontender, firm enlargement of the thyroid gland with a rubbery consistency and a pebbly surface
Goiter
T/F Weight gain in acquired hypothyroidism is mostly due to fluid retention
T, called myxedema, not true obesity
T/F School work and grades usually do not suffer in acquired hypothyroidism, even in severely hypothyroid children
T
T/F Osseous maturation is often strikingly delayed in patients with acquired hypothyroidism
T, it is an indication of the duration of the hypothy
T/F There is no indication for thyroid imaging in acquired hypothy
T
Most accurate method to follow nodule size in acquired hypothy
UTZ
Treatment of choice for acquired hypothy
Levothyroxine
MCC of thyroid disease in children and adolescents
Lymphocytic thyroiditis
MCC of acquired hypothyroidism, with or without goiter
Lymphocytic thyroiditis
Accounts for majority of infiltrating cells in lymphocytic thyroiditis
T cells (60%
MC clinical manifestations of thyroiditis
Goiter and growth retardation
Cause most cases of non-goitrous (atrophic) hypothy
Thyroiditis
Chromosomal disorders particularly associated with lymphocytic thyroiditis
Down syndrome and Turner syndrome
T/F TFT in thyroiditis are OFTEN normal
T, TSH may be slightly or even moderately elevated in some
Antibodies found in patients with lymphocytic thyroiditis
Antibody to TPO and thyroglobulin
Definitive diagnosis of lymphocytic thyroiditis can be established by
Biopsy of the thyroid
Biopsy of the thyroid is always indicated to establish a diagnosis of lymphocytic thyroiditis
F
T/F Subclinical thyroiditis is an indication for replacement therapy with levothyroxine
T
Characteristics of nodules that should be examined histologically using FNA
Prominent (ie >1cm) that persist despite suppressive therapy
Why is FNA indicated in suspicious thyroid nodules
Thyroid CA or lymphoma has occurred in patients with lymphocytic thyroiditis
Uncommon cause of thyroiditis usually preceded by a respiratory infection and affects the LEFT LOWER LOBE predominantly
Acute suppurative thyroiditis
Typical infectious agent of Acute suppurative thyroiditis
Anaerobic organisms
MCC of Acute suppurative thyroiditis
Viridans strep > S aureus > pneumococcus
Hypothy associated with exquisite tenderness of the gland, swelling, erythema, dysphagia, and limitation of head motion
Acute suppurative thyroiditis
Rare cause of hypothy in children and is thought to have a viral cause
Subacute granulomatous thyroiditis (DeQuervain)
T/F Subacute granulomatous thyroiditis remits spontaneously
T
