ENDOCRINE DISORDERS-THYROID DISORDERS 1.3 (AB) Flashcards
What is pheochromocytoma?
A chromaffin tumor that secretes catecholamines, usually located in the adrenal medulla.
What is the ‘Rule of 10’ in pheochromocytoma?
10% are bilateral, 10% are extra-adrenal, 10% are malignant, 10% occur in children, 10% are familial.
What is the incidence of pheochromocytoma in pregnancy?
Approximately 1 per 50,000 pregnancies.
What percentage of hypertensive patients have pheochromocytoma?
0.2 to 0.6%.
What are the common symptoms of pheochromocytoma?
Paroxysmal hypertensive crisis, seizures, anxiety attacks, headache, sweating, palpitations, chest pain, nausea, vomiting, pallor.
What is the standard screening test for pheochromocytoma?
Quantification of metanephrines and catecholamine metabolites in a 24-hour urine specimen.
What is the most sensitive diagnostic test for pheochromocytoma?
Determination of plasma catecholamine metabolite levels.
What are the normal plasma and urine metanephrine levels?
Plasma free metanephrine: <0.3 - 0.5 nmol/L; Urine total metanephrine: <1.3 - 2.4 mg/24 hours.
What imaging modalities are used for pheochromocytoma diagnosis?
CT or MRI for adrenal localization; MRI is preferred in pregnancy.
Why is it important to differentiate pheochromocytoma from preeclampsia?
Both can cause hypertension in pregnancy, but pheochromocytoma can lead to life-threatening complications if not diagnosed.
What is the first-line treatment for pheochromocytoma?
Immediate control of hypertension with an ⍺-adrenergic blocking agent (e.g., phenoxybenzamine).
What medication is added after α-blockade in pheochromocytoma?
β-blocking drugs such as propranolol for tachycardia.
When is surgical removal of pheochromocytoma performed in pregnancy?
Preferably in the second trimester.
What are the management options for pheochromocytoma diagnosed later in pregnancy?
Planned cesarean delivery with tumor excision or postpartum resection.
What is Cushing syndrome?
A condition caused by excessive glucocorticoids due to a pituitary adenoma, adrenal tumor, or bilateral adrenal hyperplasia.
What is the female-to-male ratio in Cushing syndrome?
3:1.
What is the most common cause of iatrogenic Cushing syndrome?
Long-term corticosteroid treatment.
What are the characteristic physical features of Cushing syndrome?
Moon facies, buffalo hump, truncal obesity due to adipose tissue deposition.
How does Cushing syndrome affect fertility?
CRH can interfere with GnRH in the HPO axis, leading to anovulation.
What is Cushing disease?
Bilateral adrenal hyperplasia caused by corticotropin-producing pituitary adenomas.
What tumors can cause ectopic Cushing syndrome?
Non-endocrine tumors producing corticotropin-releasing factor or corticotropin.
What percentage of Cushing syndrome cases are corticotropin-independent?
Less than 25%, mostly caused by adrenal adenomas.
What is the diagnostic test for Cushing syndrome?
Elevated plasma cortisol levels that cannot be suppressed by dexamethasone or elevated 24-hour urinary free cortisol excretion.
What imaging modalities are used to localize tumors in Cushing syndrome?
Serum corticotropin levels, CT, and MRI.
Why is Cushing syndrome diagnosis challenging in pregnancy?
Normal cortisol levels are elevated in pregnancy, making interpretation difficult.
What are the causes of Cushing syndrome in pregnancy?
> 50% corticotropin-dependent adrenal adenomas, ~30% pituitary adenomas, 10% adrenal carcinomas.
What are the major complications of hypercortisolism in pregnancy?
Heart failure, poor wound healing, osteoporotic fractures, psychiatric complications.
What is the most common pharmacologic treatment for Cushing syndrome before surgery?
Metyrapone (adrenal steroid synthesis inhibitor).
Why is ketoconazole concerning for male fetuses?
It blocks testicular steroidogenesis.
Why is mifepristone contraindicated in pregnancy?
It blocks cortisol action and is also used for abortion and labor induction.
What is the first-line surgical treatment for Cushing syndrome?
Transsphenoidal resection of pituitary tumors or laparoscopic adrenalectomy in the second trimester.
When can unilateral adrenalectomy be performed in pregnancy?
Early third trimester.
What is Addison disease?
Primary adrenal insufficiency due to adrenal gland destruction.
What is the most common cause of Addison disease in developed countries?
Autoimmune adrenalitis.
What is the most common cause of Addison disease in resource-poor countries?
Tuberculosis.
What effect does untreated adrenal insufficiency have on fertility?
It frequently causes infertility, but ovulation is restored with replacement therapy.
What are the classic symptoms of Addison disease?
Weakness, nausea, vomiting, weight loss.
What are the key diagnostic findings in Addison disease?
Low plasma cortisol, elevated ACTH levels.
What pregnancy complications are associated with adrenal insufficiency?
Preterm delivery, low birth weight, cesarean delivery.
What is the treatment for Addison disease?
Glucocorticoid and mineralocorticoid replacement.
How is glucocorticoid dosing adjusted in pregnancy for Addison disease?
A 20-40% dose increase after midpregnancy to mimic physiological cortisol elevation.
What is the stress dose of corticosteroids for labor or surgery in Addison disease?
Hydrocortisone 100 mg IV every 8 hours for 48 hours.
What is the most common cause of primary aldosteronism (Conn syndrome)?
Adrenal adenoma (75% of cases)
What are the three main causes of primary aldosteronism?
Adrenal adenoma, idiopathic bilateral adrenal hyperplasia, rare cases of adrenal carcinoma
What are the hallmark symptoms of primary aldosteronism?
Hypertension, hypokalemia, muscle weakness
How is primary aldosteronism diagnosed?
Confirmed by high serum or urine aldosterone levels
Why is diagnosing hyperaldosteronism in pregnancy difficult?
Progesterone blocks aldosterone action, leading to very high aldosterone levels
What laboratory test is useful for diagnosing hyperaldosteronism?
Plasma aldosterone-to-renin activity ratio
What happens to hypertension in hyperaldosteronism as pregnancy progresses?
It worsens
What are the medical management options for hyperaldosteronism?
Potassium supplementation, antihypertensive therapy (spironolactone, beta-blockers, calcium channel blockers), amiloride, eplerenone
What is the definitive treatment for primary aldosteronism?
Laparoscopic tumor resection
What pregnancy complications are associated with hyperaldosteronism?
Higher prevalence of chronic hypertension, preeclampsia, preterm birth, intrauterine growth restriction (IUGR)
What is the most common type of pituitary adenoma in women?
Prolactinoma (75%)
What are the key symptoms of prolactinoma?
Amenorrhea, hyperprolactinemia, galactorrhea
How are prolactinomas classified based on size?
Microadenomas (<10mm) and macroadenomas (>10mm)
What imaging modality is recommended for prolactinoma diagnosis?
CT or MRI, but only if symptoms develop
What is the first-line treatment for microadenomas?
Bromocriptine (dopamine agonist)
What is the recommended treatment for suprasellar macroadenomas before pregnancy?
Surgical resection
How are macroprolactinomas monitored during pregnancy?
Frequent monitoring with visual field testing each trimester
What are the two main dopamine agonists used to treat prolactinomas?
Bromocriptine and cabergoline
What is the first-line treatment for acromegaly outside pregnancy?
Transsphenoidal resection of the pituitary adenoma
What laboratory finding confirms acromegaly?
Elevated insulin-like growth factor 1 (IGF-1) serum levels
Why is pregnancy rare in women with acromegaly?
50% have hyperprolactinemia and anovulation
What pregnancy complications are associated with acromegaly?
Gestational diabetes, hypertension
What is the first-line treatment for acromegaly during pregnancy?
Monitoring for tumor enlargement; dopamine agonists are less effective
What is the cause of diabetes insipidus (DI)?
Vasopressin (ADH) deficiency due to neurohypophysis agenesis or destruction
What are the types of DI encountered during pregnancy?
Primary polydipsia, gestational DI, nephrogenic DI, transient secondary DI
What is the treatment for DI in pregnancy?
Desmopressin (DDAVP)
Why do pregnant women with DI require higher doses of desmopressin?
Increased metabolic clearance rate due to placental vasopressinase
What causes Sheehan syndrome?
Pituitary ischemia and necrosis due to obstetrical blood loss
What are the key symptoms of Sheehan syndrome?
Persistent hypotension, tachycardia, hypoglycemia, lactation failure
What is the treatment for Sheehan syndrome?
Glucocorticoid replacement therapy, thyroid, gonadal, and growth hormone replacement
What is lymphocytic hypophysitis?
A rare autoimmune disorder causing pituitary inflammation and destruction
What are the common symptoms of lymphocytic hypophysitis?
Headaches, visual field defects, sellar mass, elevated serum prolactin
What autoimmune diseases are associated with lymphocytic hypophysitis?
Hashimoto thyroiditis, Addison disease, type 1 diabetes, pernicious anemia
What is the treatment for lymphocytic hypophysitis?
Glucocorticoids, pituitary hormone replacement therapy
