Endocrine Flashcards
(173 cards)
Cushing’s disease vs Cushing’s syndrome
The disease is the most common cause of Cushing’s syndrome
Disease is ACTH-secreting pituitary adenoma that causes increase in cortisol
Syndrome is hypercortisol state
Causes of Cushing’s Syndrome
Cushing’s disease (pituitary adenoma, most common cause)
Chronic steroid use
Adrenal tumor
Ectopic production by ACTH-secreting tumor (often small lung cell carcinoma)
Patients most commonly affected by Cushing’s Syndrome
premenopausal women
Hallmark findings of Cushing’s Syndrome
buffalo hump moon face proximal muscle weakness pigmented striae obesity - centrally located with skinny limbs
Best lab to dx Cushing’s Syndrome
24 hr urine for free cortisol
> 125 is diagnostic
How does overnight dexamethasone suppression test help dx Cushing’s Syndrome?
Distinguishes pituitary vs ectopic cause of cortisol elevation
Patient gets 1 mg of dexamethasone at 12pm. 8am plasma ACTH measured
Pituitary tumor (Cushing's Disease) - low ACTH; negative feedback Ectopic tumor - no ACTH change
How is Cushing’s Disease treated?
transsphenoidal resection with hydrocortisol replacement, but if tumor cannot be removed chemo or radiation therapy useful
How is Cushing’s Syndrome treated?
Metyrapone and Ketoconazole may suppress hypercortisolism
Parenteral octreotide may suppress ACTH
Often patients treated for Cushing’s syndrome will go into cortisol withdraw and require steroid tapering therapy with hydrocortisone or prednisone
Clinical findings of Addison’s Disease
Sparse axillary and pubic hair
Hyperpigmentation of skin, esp. creases or pressure areas (waist band/bra line)
Hypotension and small heart
What chemicals/lytes are low in Addison’s Disease? which are elevated?
Low – Na and glucose
Elevated – K+, Ca2+ and BUN
Diagnostic lab test for Addison’s disease
low plasma cortisol and aldosterone with elevated ACTH
Treatment of Addison’s disease
Replacement with oral hydrocortisone or prednisone
Fludrocortisone also useful for sodium retention
DHEA may also be given
Difference between pathophysiology of primary and secondary hyperthyroidism
Primary hyperthyroidism: problem with thyroid
Secondary hyperthyroidism: problem with pituitary
___________ is the most common cause of hyperthyroidism. It is an autoimmune disease in which the body creates antibodies that bond to the TSH receptors and force excessive T3/T4 production.
Graves’ disease
20-40% of patients with Grave’s disease have what findings that can distinguish from other hyperthyroid issues?
conjunctivitis
exophthalmos (bulging of eyes)
pretibial myxedema (non-pitting edema of knee)
thyroid bruit
Some of the many symptoms of hyperthyroidism
Eyes: stare, lid lag, diplopia
CV: Tachycardia, A-fib, palpitations, chest pain
Skin: Fine hair, warm/moist skin, onycholysis
Mental changes: irritability, Nervousness, fatigue
Heat intolerance, sweating
Weight loss, increased appetite
Hyperreflexia
Goiter
What is a thyroid storm?
very rare but severe form of hyperthyroidism
risk factors include stressful illness, thyroid surgery, radioactive iodine treatment
symptoms: fever, tachycardia, vomiting/diarrhea, dehydration, muscle weakness, confusion
How does hyperthyroidism affect TSH, T3, T4
TSH decreased (primary) or elevated (secondary)
T4 elevated
T3 elevated
What is specifically elevated in Graves’ disease?
anti-TSH receptor antibodies
Radioactive iodine uptake scan results of Graves disease
thyroid has increased iodine uptake
First line treatment for acute hyperthyroidism and thyroid storm? Long term control?
Acute: beta blockers (especially propanol)
Long term: Methimazole and propylthiourcial (PTU)
Definitive tx: Radioactive iodine ablation
How to treat A-fib of hyperthyroidism?
Digoxin
Warfarin to prevent possible clotting
Pathway of T3/T4 production from hypothalamus signaling
Hypothalamus → thyroid releasing hormone → pituitary → thyroid stimulating hormone → thyroid → T3 and T4
Why might a patient have hypothyroidism?
Thyroiditis
Patient doesn’t have thyroid
Meds: amiodarone, lithium, PTU & Methimazole
Iodine deficiency