Hypothyroidism (Darrow) - MT Flashcards
Hypothyroidism aka myxedema indicates what disease process?
Lymphedema w/ accumulation of glycosaminoglycans in skin with doughy endfeel upon palpation
10 hypos of hypothyroidism?
- Hyporeflexia
- Hypomentia
- Hypothermia
- Hypoventilation
- Hypotension or diastolic HTN
- Hypohemoglobinemia
- Hypoglycemia
- Hyponatremia (dec renal Na/K ATPase)
- Hypometabolism of drugs and lipid (hyperlipidemia)
- Hypocorticolism (pituitary insuff)
- Hypodrenalism (addison’s disease)
Common causes of Hypothyroidism in children vs. adults
Children: Iodine deficiency and Congenital defects
Adults: Hashimoto’s disease
What is the MHC II molecule and Antibodies involved with Hashimoto’s disease?
- HLA-DR5
- Antibodies to TPO and Thyroglobulin
Thyroid appearance grossly and RAI uptake profile in Hashimotos disease?
- thyroid is usually enlarged and boggy
- spotty uptake with low, high, or normal RAI
Patient presents with dry eyes and mouth, her family history is positive for pernicious anemia and celiac disease. Free T4 levels are within normal ranges. She also has an enlarged, firm thyroid gland. What additional test will aid in confirming the diagnosis, and what is the diagnosis?
- TPO antibody assay
- Subclinical Hypothyroidism (normal T4 but high TSH)
Subclinical hypothyroidism puts a patient at risk for what 3 things?
- Elevated lipids / metabolic syndromes
- CHF and ArterioScleroticHeartDisease (especially if TSH>10 mlU/L)
- Poor iron absorption anemia
How does a thyroid deficiency cause anemia?
- thyroid deficiency decreases Iron absorption and interferes with EPO activity
Treatment guidelines for Sublcinical hypothyroidism:
- When do you treat for TSH > 5 mlU/L?
- When do you treat for TSH > 10 mlU/L?
- When do you treat for TSH > 2.5 mIU/mL?
- When do you treat for TSH 4-6 mlU/L?
- If anti TPO antibodies are present
- If no antibodies are present
- If found in Pregnant patients with TPO antibodies
- If found in Elderly patients
Hepatic cause of hypothyroidism, and how does it cause the deficiency?
Hepatitis C - increased propensity to antithyroid antibodies
What drugs can cause hypothyroidism?
Lithium, interferon, amiodarone
Other autoimmune diseases (HLA B8 - DR, DQ) associated with Hashimoto’s disease include? (autoimmune adrenal, autoimmune metabolic, glandular autoimmune, autoimmune GI)
- Addison’s disease
- DM
- Sjogren’s syndrome
- Primary Biliary cirrhosis
A 65 y/o female is seen for exhaustion, weakness, dizziness, chest pain, numbness in both thumbs and index fingers (especially while driving) , constipation, arthralgias and pedal edema. She has recently developed diastolic hypertension. History is positive for exertional chest pain relieved by rest. She had taken some anti-thyroid medication at age 20 because of a 20 lb weight loss. She reports some increasing deafness.
What would you expect on this patient’s physical exam particularly in her skin, speech, gross thyroid appearance, and heart rate?
- yellow skin
- slow and hoarse speech
- mild goiter
- bradycardia
What changes occur in the nails, hair, eyebrows, and legs of hypothyroid patients?
- nails brittle
- hair thinning
- loss of lateral 1/3 of eyebrows
- pedal edema
Gallavardin phenomenon is a grade II/VI is a systolic ejection murmur heard at the ______, with a high pitched systolic murmur at the ______. These murmurs are due to what?
- Base
- Apex
- dissociation b/t noisy and musical elements of an Aortic Stenosis murmur (musical at left sternal border and apex, noisy at aortic area)
Hypothyroid patients can display what 2 cardiac signs?
- Gallavardin phenomenon
- Diastolic BP elevation (example 138/112)
Usually what are the cholesterol and Iron & TIBC levels found in patients with long standing untreated hypothyroidism?
- Cholesterol is high
- Iron is decreased with an increased TIBC
Hypothyroidism, through what mechanism, can cause what type of Hyponatremia?
Euvolemic d/t decreased Na/K ATPase activity
(Urinary Na > 20 meqL)
A hypothyroid patient that has been treated with thyroid hormone but continues to have fatigue may be suffering from what?
What would you treat this condition with?
- Covert iron deficiency
- Treat with iron to obtain ferritin over 100 mcg/L
TSH levels should be maintained in what range when treating hypothyroidism?
- TSH b/t 0.5-2.0 mU/L
Myxedema crises can be precipitated by what? (x4)
medicine non cmpliance, surgery, stress, infection
along with the classic 10 hypos, patients have a myxedema crisis may display hypersensitivity to what drug type? What is the mortality rate for these crises?
- Opiates
- 20-50% mortality
treat a myxedema crisis with what 3 drugs?
- hydrocortisone IV
- Levothyroxine T4 IV
- LT3 IV
Another name for a severe non-thyroidal illness that causes low TSH is?
TNF- Euthyroid sick syndrome
Sick enzymes and serum inhibitors with low total T3, low free T3, low total T4, and high reverse T3 are due to what 2 things?
- Decreased 5’ deiodinase (esp liver) = low T3 and high reverse T3 (surgery)
- Increased interleukin = displaced binding of T4 (major illness) = decreased total T4 n increased T3 uptake
Low TSH with severe euthyroid sick syndrome is due to what 2 factors? (Low T3 syndrome)
- Drugs: steroid admin, CCBs, DOPAMINE, nsaids, opiates
- Increased IL-1, IL-6, TNF alpha
In the most severe cases of euthyroid sick syndrome which molecule out of the following are found at the high levels? The lowest?
- Free T4
- T4
- T3
- rT3
- highest is rT3
- lowest is T3
A 50 y/o female presents with hoarseness, diminished sense of taste and smell, menorrhagia, thinning of the lateral third of the eyebrows, thickening of the tongue, cardiac enlargement and new onset galactorrhea. Laboratory results confirm the diagnosis and the physician orders a brain CT that reveals pituitary enlargement. The best approach is (to):
Thyroid replacement
Thyrotrope hyperplasia from increased TRH may also inhibit testosterone and estrogen production. Why?
TRH stimulates lactotrophs to produce prolactin
