Question | Answer |
Hypothyroidism results from? | 1. Deficient production from:
a) gland (primary Hypothyroidism)
b) reduced TSH (Secondary)
2. Defect in receptor activity |
Cause of CONGENITAL HYPOTHYROIDISM? | >Thyroid Dysgenesis - 85%
> Inborn errors of Thyroxine Synthesis - 10%
>Transplacental maternal thyrotropine - receptor blocking antibody - 5% |
Familial Congenital Hypothyroidism is caused by? | Inborn Errors of thyroid hormone synthesis |
Appearance of manifestations of SEVERE Congenital Hypothyroidism Appears? Less Severe? | Early manifestations - SEVERE
Late Manifestations - Less Severe |
Epidemiology:
a) Race
b) gender | a) Hispanic and Native Americans > Blacks
b) F>M (2:1) |
Clinical manifestations: | > Large anterior and posterior fontanels - first clues secondary to myxedema of the brain
> Prolonged Physiologic Jaundice - >2 weeks, may be the earliest signs
> 1st month: feeding difficulties, choking spells, lac of interest, sluggish, somnolence |
Anemia associated with congenital hypothyroidism | Macrocytic anemia
- intractable to treatment |
Most common Manifestation/s for Congenital Hypothyroidism? | Cardiac Anomalies |
If untreated or undetected (more than 1 month) | > Retardation of mental and physical development
> Stunted growth, HC normal or increased
> Fontanels- opened
> Dry skin
> Fat deposition above clavicles |
Diseases Detected by Newborn Screening? | > Phenylketonuria
> G6PD
> Congenital Adrenal Hyperplasia
> Congenital Hypothyroidism
> Galactosemia |
Diagnostics for Congenital Hypothyroidism? | > Newborn Screening
> (American) T4 determination --> TSH if T4 is low
> (European and Japanese) TSH measurement - detects primary hypo and subclinical hypo |
Thyroid hormones Profile for Congenital Hypothyroidism? | T4 - LOW
T3 - NORMAL
TSH - HIGH
Serum THYROGLOBULIN - LOW
** Serum Prolactin - High |
Radiologic Findings CHypoThy | >Distal Femoral Epiphysis is ABSENT (epiphyseal dysgenesis)
. BEAKING Deformity - T12, L1, L2 |
ECG findings for CHypoThy | Low voltage P and T waves
Diminished Amplitude of QRS |
Treatment for CHypoThy | ORAL LEVOTHYROXINE
- 10-25 mcg/kg |
Monitoring after treatment | T4 and TSH monthly for the first 6 months, then every 2-3 months until 2 y/o |
How many points in the IQ is reduced? | 5-20 points |
Neuropsychological Sequelae of congenital Hypothyroidism? | > Incoordination
> hypotonia/ hypertonia
> Short attention span
> Speech Problems
> neurosensory hearing defects |
ACQUIRED HYPOTHYROIDISM Epidemiology | > more common that Congenital
> F>M (2:1) |
Cause of Acquired Hypothyroidism | Chronic Lymphocytic Thyroiditis (Hashimoto's Thyroiditis) |
Other causes of Hypothyroiditis (acquired) | - Autoimmune: Pernicious Anemia, Klinefelter, Down's
- Irradiation
- Meds: AMIODARONE
- liver hemangioma - inc. type III deiodinase |
Manifestations: | - decelerated growth - 1st clinical sign
- Goiter - Enlarged gland, non-tender, firm, rubbery consistency
- hypothyroidism s/sx
- precocious puberty - inc. TSH |
What is Goiter? | Enlarged thyroid gland |
T/F: Goiter is caused by increased thyroid hormone secretion? | FALSE. Increased PITUITARY SECRETION (TSH)
can be Euthyroid, Hypothyroid, Hypothyroid, Congenital or acquired , endemic or sporadic |
Congenital Goiter is caused by? | > Fetal thyroxine Synthetic defect
> Administration of Anithyroid drugs during pregnancy |
Radiologic findings? | Anterior deviation of the Trachea |
Acquired Goiter is caused by? | > Lyphocytic Thyroiditis (Hashimoto)
> Iodine Ingestion
> Drugs |
Thyroid picture of Acquired Goiter? | Euthyroid or Hypothyroid |
Other name for ENDEMIC GOITER? | Cretinism |
Cause of Cretinism | IODINE DEFICIENCY |
Clinical Manifestations | > Mild - no noticeable neck mass
> Moderate - evident neck mass and may disappear with maturity may reappear during pregnancy
> Severe - large neck mass |
Types of Endemic Cretinism? | 1. Neurologic Type - Zaire
2. Myxedematous Type - Papua New Guinea |
Manifestations of Neurologic Type? | > MR
> Deaf mutism
> gait and standing disturbances
> normal pubertal development |
Pyramidal Signs of Neurologic type? | > Babinski
> hyperreflexia
> ankle clonus |
Thyroid Picture of Neurologic type? | EUTHYROID |
Manifestations of Myxedematous type? | > MR
> deaf with neurologic symptoms
> delayed growth and sexual development
> absent goiter on UTZ |
Thyroid picture? | T4 LOW; TSH marked elevation |
Pathogenesis of Neurologic type? | Direct effects of maternal and fetal iodine deficiency (hypothyroxinemia) |
Pathogenesis of Myxedematous type? | >Selenium Deficiency
> auto-antibodies/ autoimmune |
Treatment for Cretinism? | IODINATED POPPY SEED OIL to women - prevents iodine deficiency in future pregnancies for 5 years |
HYPERTHYROIDISM | excessive secretion of Thyroid Hormones |
Cause of GRAVE'S DISEASE? | production of thyroid stimulating immunoglobulin |
Peak incidence? | 11-15 y/o |
Gender ratio? | F>M (5:1) |
Earliest manifestation of Grave's? | Emotional Disturbances with motor hyperactivity |
Description of Exophthalmos | > lagging upper eyelid
> impaired convergence
> |
Anxious Stare | EXOPHTHALMOS |
An acute condition that is manifested by hyperthermia, severe tachardia, rapid progression of coma, and is precipitated by stressful conditions. Hx: Hyperthyroidism | Thyroid crisis/Thyroid Storm |
diagnostics for Thyroid storm? | > inc Serum T4, Free T4 and T3
> low TSH
> (+) antithyroid antibodies and thyroid peroxidase antibodies
> (+) thyrotropin stimulating antibodies |
Treatment for Thyroid storm? | > Anti-thyroid: PTU
> Hydrocortisone
> Propanolol
> Supportive mngt. (treat underlying cause) |
conditions for radioiodine treatment of surgery? | > cooperation for medical management is not possible
> trial of meds has failed
> side effects preclude futher use of antithyroid meds |
Ocular manifestations of Grave's Disease? | Pain, Lid erythema, Chemosis, decrease EOM function, Decreased Visual Acuity |
Papillary Carcinoma | - RET rearrangements
- Familial; Autosomal Dominant |
Anaplastic Thyroid Carcinoma | - p53 point mutations |
Procedure that causes Thyroid carcinomas? | Radiation Therapy |
Amount of Grey that causes a 7.7 relative risk | 1 Gy |
Most Common Histologic type of Thyroid Ca | Papillary/Follicular |
Most fatal Histologic type? | Anaplastic |
MC site of mets | Lungs |
Gold standard for diagnosis | FNAB |
Determines Solidity of the tumor | Ultrasound |
Determines radionucleid uptake | Thyroid Scan |
Radioisotopes used for DIAGNOSIS | Iodine - 123
99m Technetium pertechnetate |
cold nodules | most are BENIGN |
Hot Nodules | Malignant |
Treatment for tumors <1 cm | subtotal thyroidectomy followed by suppressive doses of thyroid hormone |
Small but multicentric tumors | Total Thyroidectomy |
Tumors >1 cm | Total thyroidectomy with LN excision |
Radioisotopes used for TREATMENT | Iodine - 131 (30-100 mCi) |
Drugs given after Surgery? | Na L - thyroxine |