Endocrinology Flashcards
What occurs with Thyroid Hormones in normal aging?
Decreased T4 secretion (but decreased clearance), so NL
Decreased or NL T3 (due to decreased peripheral conversion)
TSH is NL or increased
Most common cause of hypothyroidism in older adults?
Hashimoto disease (chronic autoimmune thyroiditis)
How do you diagnose primary hypothyroidism?
High TSH, low T4
What is subclinical hypothyroidism?
TSH >4.5 with normal T4
When should you treat subclinical hypothyroidism?
In older adults iwth TSH >10 (symptom benefit and possibly lower ischemic heart disease)
What do TSH levels do during nonthyroid illness?
low then transiently increase during the recovery phase
What do T3 and T4 levels do during acute nonthyroid illness?
low T3 (with normal TSH) or
Low T4 (with normal TSH)
Starting doses for synthroid
25 mcg/day or 50 mcg/day (if no e/o CAD)
What should occur before treating severe hypothyroidism?
testing for adrenal insufficiency (for stress dose steroids)
What is the target TSH level for older adults?
4-7 mIU/L
What is the most common cause of hyperthyroidism in older adults?
Graves disease
How may older adults present with hyperthyroidism?
Apathetic thyrotoxicosis (depression, inactivity, lethargy, withdrawn behavior with anorexia, weight loss, constipation, muscle weakness or cardiac symptoms)
What is T3 toxicosis associated with?
toxic adenomas or toxic multinodular goiters (more common in elderly)
What is the next step for someone with hyperthyroidism?
Radioactive iodine uptake and scanning
When should hyperthyroidism be treated?
In all adults >60 with TSH <0.1 mIU/L OR if TSH 0.1-0.4 with symptoms or comorbidities like heart disease or osteoporosis
When should a thyroid nodule be FNA’s?
if cold on RAI or >1 cm in size with high risk features, >1.5cm in size for low risk features or >2cm in size for very low risk features
When will you see high phos with high calcium?
Local osteolytic hypercalcemia
What are the indications for surgery for primary hyperparathyroidism?
symptomatic hyperparathyroidism OR asymptomatic with:
-Calcium >1 mg/dL above normal
-CrCl <60
-BMD less than -2.5
-Vertebral fracture
-Nephrolithiasis
-24-hour urine calcium >400 mg/day with increased stone risk
-Neurocognitive or neuropsychiatric symptoms (possibly)
What is an alternate to those who cannot get parathyroid surgery?
Cinacalcet (but does not increase BMD so may need to use bisphosphonate)
What is the next step if abnormally low Testosterone?
LH and FSH (if these are low, check a prolactin)
When is it reasonable to replace testosterone?
with levels <200 ng/dL and symptoms
