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340 SEcTion iii EndocrinE ` endocrine—PAthology EndocrinE ` endocrine—PAthology
Hypothyroidism vs hyperthyroidism
Findings Hypothyroidism Hyperthyroidism
metAbolic Cold intolerance, sweating, weight gain Heat intolerance, sweating, weight loss
+
+
( basal metabolic rate calorigenesis), ( synthesis of Na -K ATPase basal
hyponatremia ( free water clearance) metabolic rate calorigenesis)
sKin/hAir Dry, cool skin (due to blood flow); coarse, Warm, moist skin (due to vasodilation); fine hair;
brittle hair; diffuse alopecia; brittle nails; onycholysis ( A ); pretibial myxedema in Graves
A
puffy facies and generalized nonpitting edema disease
(myxedema) due to GAGs in interstitial
spaces osmotic pressure water retention
ocUlAr Periorbital edema Ophthalmopathy in Graves disease (including
periorbital edema, exophthalmos), lid lag/
retraction ( sympathetic stimulation of
levator palpebrae superioris and superior tarsal
muscle)
gAstrointestinAl Constipation ( GI motility), appetite Hyperdefecation/diarrhea ( GI motility),
appetite
mUscUlosKeletAl Hypothyroid myopathy (proximal weakness, Thyrotoxic myopathy (proximal weakness,
CK), carpal tunnel syndrome, myoedema normal CK), osteoporosis/ fracture rate (T 3
(small lump rising on the surface of a muscle directly stimulates bone resorption)
when struck with a hammer)
reProdUctiVe Abnormal uterine bleeding, libido, infertility Abnormal uterine bleeding, gynecomastia,
libido, infertility
neUroPsychiAtric Hypoactivity, lethargy, fatigue, weakness, Hyperactivity, restlessness, anxiety, insomnia,
depressed mood, reflexes (delayed/slow fine tremors (due to β-adrenergic activity),
relaxing) reflexes (brisk)
cArdioVAscUlAr Bradycardia, dyspnea on exertion ( cardiac Tachycardia, palpitations, dyspnea, arrhythmias
output) (eg, atrial fibrillation), chest pain and systolic
HTN due to number and sensitivity of
β-adrenergic receptors, expression of cardiac
sarcolemmal ATPase and expression of
phospholamban
lAbs TSH (if 1°) TSH (if 1°)
free T 3 and T 4 free T 3 and T 4
Hypercholesterolemia (due to LDL receptor LDL, HDL, and total cholesterol
expression)
FAS1_2019_08-Endocrine.indd 340 11/7/19 4:30 PM
