Hormones Flashcards
What is Sheehan syndrome?
Sheehan syndrome, also called post-parturition pituitary necrosis, refers to the necrosis of cells of the anterior pituitary gland following significant post-parturition bleeding, hypovolemia, and shock. The first and most common symptom of Sheehan syndrome is agalactorrhea, or the absence of lactation. Other symptoms are associated with loss of pituitary gland hormone production and may include amenorrhea or oligomenorrhea, hot flashes, and/or decreased sex drive. Symptoms of hypothyroidism such as fatigue, bradycardia, hypotension, weight gain, and constipation may occur months later, along with the loss of axillary and pubic hair. Adrenal insufficiency can also occur with symptoms of fatigue and weight loss. Laboratory values that may support secondary adrenal insufficiency due to Sheehan syndrome include hyponatremia, anemia, and hypoglycemia.
What is adrenal insufficiency?
Adrenal insufficiency is an uncommon clinical condition characterized by failure of adrenocortical function which results in impaired secretion of glucocorticoids only or of glucocorticoids and mineralocorticoids and adrenal androgens which are crucial for energy, salt and fluid homeostasis, and androgen activity, respectively.
What is Addison disease?
Addison disease is an acquired primary adrenal insufficiency, a rare but potentially life threatening endocrine disorder that results from bilateral adrenal cortex destruction leading to decreased production of adrenocortiocal hormones, including cortisol, aldosterone, and androgens. The most common cause of primary adrenal insufficiency is autoimmune adrenalitis (Addison disease) associated with increased levels of 21-hydroxylase antibodies. The treatment for Addison disease is glucocorticoids (hydrocortisone) and mineralocorticoids (fludrocortisone) replacement therapy.
What is Cushing syndrome and what is Cushing disease?
Cushing syndrome is caused by prolonged exposure to high circulating levels of cortisol, and the two main etiologies are endogenous hypercortisolism and exogenous hypercortisolism. Cushing disease is ACTH-dependent cortisol excess due to a pituitary adenoma, and it is responsible for 80% of endogenous Cushing syndrome.
Patients with Cushing syndrome or Cushing disease will have increased fat deposit in the upper half of the body leading to “Buffalo torso”, characteristic moon facies (earlobes are not visible from the front), thin arms and legs, acne, hirsutism, proximal muscle weakness of the shoulder and hip girdle muscles, and wide purplish abdominal striae.
What is postoperative diabetes insipidus?
Postoperative diabetes insipidus is caused by vasopressin deficiency, and it is one of the most reported complications after pituitary tumor surgery. Postoperative diabetes insipidus is characterized by polyuria, hypotonic urine (low urine specific gravity and urine osmolality) and increase serum osmolality. Other clinical symptoms associated with postoperative diabetes insipidus are thirst and hypovolemia.
What is hyperaldosterism, and what is the difference between primary and secondary hyperaldosterism?
Hyperaldosteronism is the excess production of aldosterone from the adrenal gland.
Primary hyperaldosteronism is due to the excess production of the adrenal gland, more specifically the zona glomerulosa. It can present more commonly as a primary tumor in the adrenal gland known as Conn syndrome or as bilateral aldosterone excess known as idiopathic hyperaldosteronism.
Secondary hyperaldosteronism is due to the excessive activation of the renin-angiotensin-aldosterone system (RAAS). This activation can be due to a renin-producing tumor, renal artery stenosis, or edematous disorders such as left ventricular heart failure, pregnancy, cor pulmonale, or cirrhosis with ascites.
What is the aldosterone/renin ratio (ARR), and how is it interpreted?
The aldosterone-to-renin ratio (ARR) is a screening test for primary aldosteronism.
ARR = [Plasma Aldosterone Concentration (PAC) in ng/dL] / [Plasma Renin Activity (PRA) in ng/mL/hr]
The ARR is interpreted as follows: The screening test is positive if the ARR is >30 and the concentration of aldosterone is > 10 ng/dL.
What is Conn syndrome?
Conn syndrome is a cause of primary aldosteronism that is the result of an aldosterone producing adenoma in the zona glomerulosa of the adrenal cortex. Conn syndrome can be treated with adrenalectomy.
What is idiopathic hyperaldosteronism?
Idiopathic hyperaldosteronism is a cause of primary aldosteronism that results from bilateral aldosterone excess from the zona glomerulosa. Idiopathic hyperaldosteronism is treated with mineralocorticoid antagonists, such as spironolactone and eplerenone.
What are pheochromocytomas?
Pheochromocytomas are tumors arising from the chromaffin cells of the adrenal medulla. The clinical manifestations of these tumors are primarily related to the excessive secretion of catecholamines. Pheochromocytomas can be benign or malignant, and they are frequently associated with familial syndromes like neurofibromatosis type 1, multiple endocrine neoplasia type II, and Von-Hippel Linda’s disease. Pheochromocytomas can be secondary causes of hypertension.
What is the syndrome of apparent mineralocorticoid excess (AME)?
The syndrome of apparent mineralocorticoid excess (AME) is an autosomal recessive disorder characterized by hypertension, hypokalemia, low renin, and hypoaldosteronism. AME is caused by a deficiency of 11B-hydroxysteroid dehydrogenase, which results in a defect of the peripheral metabolism of cortisol to cortisone. As a consequence, the serum cortisol half-life is prolonged, ACTH is suppressed, and the serum cortisol concentration is normal.
AME is treated pharmacologically with dexamethasone, a steroid that has essentially pure glucocorticoid effects without any mineralocorticoid activity. Dexamethasone shuts down the adrenal production of cortisol and reduces the inappropriate mineralocorticoid effects while providing adequate glucocorticoid activity.
What are paragangliomas?
Paragangliomas are rare, catecholamine secreting neuroendocrine tumors commonly located in paravertebral sympathetic ganglia in the abdomen or the organ of Zukerkandl, a cluster of cells near the bifurcation of the aorta.
What are multiple endocrine neoplasia (MEN) syndromes, and what are the characteristics of the three most common syndromes?
Multiple endocrine neoplasia (MEN) syndromes are rare hereditary diseases in which more than one endocrine gland develops benign or malignant tumors.
MEN1 is characterized by tumors in the parathyroid glands, pancreas, and pituitary gland.
MEN2a is characterized by medullary thyroid cancer, pheochromocytomas, and parathyroid tumors.
MEN2b is characterized by medullary thyroid cancer, pheochromocytomas, and neuromas.
What is myxedema coma?
Myxedema coma is a rare and extreme complication of hypothyroidism with multiple organ abnormalities associated with altered sensorium, and it can be fatal.
What is Hashimoto’s thyroiditis?
Hashimoto’s thyroiditis, also known as chronic autoimmune thyroiditis and chronic lymphocytic thyroiditis, is an autoimmune disease in which thyroid cells are destroyed via cell and antibody-mediated immune processes. It is the most common cause of hypothyroidism in developed countries. The serum of a patient with Hashimoto’s thyroiditis will be positive for antithyroid peroxidase (TPO antibodies) and antithyroglobulin antibodies.
