Endo Flashcards
What are the actions of PTH on the kidneys?
PTH has several effects on the renal tubular cells.
It stimulates calcium reabsorption in the distal tubule, enhances 1-alpha-hydroxylase activity (converts vitamin D to its active form), and interacts with receptors on the basolateral membranes of the proximal tubule cell (increases urinary cAMP).
Lowering chronically elevated blood glucose levels, and thus insulin levels, leads to an __________ of insulin receptors.
upregulation
Upregulation occurs primarily through two general mechanisms: increasing the number of receptors, or increasing the sensitivity of receptors. In patients with chronic hyperglycemia and hyperinsulinemia (the opposite of what eventually occurs in this patient), insulin receptor down regulation occurs through endocytosis of the hormone-receptor complex that gradually reduces the number of insulin surface receptors.
A one-month old girl is hospitalized for failure to thrive. She is noted to have ambiguous genitalia on exam and vital signs reveal hypotension. Labs are notable for hyponatremia, hyperkalemia, low aldosterone, low cortisol, high ACTH, and elevated testosterone.
What is the likely dX?
21-OH deficiency
How does 21-OH deficiency present?
as salt wasting with hypotension and ambiguous female genitalia or male precocious puberty. Sodium is therefore low and potassium is high.
A patient has an abdominal mass and opsoclonus-myoclonus syndrome (OMS), which together are highly suggestive of what?
abdominal neuroblastoma.
What is Infiltrative ophthalmopathy and what disease process is it ~w/?
Graves’ disease.
TSH receptors are also present on orbital preadipocyte fibroblasts. When stimulated by TRAbs, they synthesize hydrophilic glycosaminoglycans. The accumulation of glycosaminoglycans, infiltration of fat and T-cells in the retroorbital space, and edema of the extraocular muscles all lead to exophthalmos, or proptosis.
What manifestation of Graves disease is LEAST likely to be resolved with radioactive Iodine Tx?
infiltrative ophthalmopathy is caused by the accumulation of glycosaminoglycans and not increased thyroid hormone, this manifestation is least likely to improve with radioactive iodine therapy.
