Endocrine Flashcards
Common symptoms seen in Congenital Hypothyroidism?
Presents a few months after birth (when T4 is down). Hypotonia (floppy baby), Constipation, Umbilical Hernia. Treat with Levothyroxine.
A man comes in with severe muscle cramps, a tingling sensation around the mouth, and feeling of choking. His BP is low. When you tap anterior to the ear, his perioral muscles twitch (Chvostek sign). Diagnosis? Most common cause?
He is hypocalcemic (most likely secondary to hypoparathyroidism). The most common cause is injury to the parathyroid during thyroid surgery.
What’s the function of thyroid peroxidase?
It catalyzes the oxidation of iodide (I to I2), the iodination of thyroglobulin, and the coupling reaction between 2 iodized tyrosine residues (ie 2 DITs to form T4, or 1 MIT and one DIT to form T3).
Thyroid peroxidase is attacked (autoimmune) in patients w/ Autoimmune thyroiditis (Hashimoto’s).
What are the markers for osteoblasts and osteoclasts?
Osteoblasts: Bone specific alkaline phosphatase (b/c osteoblasts secrete alk phos when they are synthesizing bone matrix).
Osteoblasts: Urinary deoxypyridinoline (best), Urinary hydroxyproline, Tartrate-resistant acid phosphatase.
A patient has persistent diabetes insipidus. When given exogenous ADH, the osmolarity of his urine greatly increases. Where is the damage most likely to have occurred?
In the hypothalamic nucleus. ADH is produced there, then moved to the posterior pituitary where it’s released. Permanent DI is indicative of a hypothalamic injury, whereas transient DI is indicative of a posterior pituitary injury.
A patient presents with primary hyperaldosteronism (due to an adrenal mass). What would you expect their sodium, potassium, and bicarb levels to be?
Sodium=normal. This is due to aldosterone escape (increased RBF, increased release of ANP).
Potassium=low (same with H). It’s excreted in exchange for sodium reabsorption.
Bicarb=High (H excretion promotes bicarb production). Metabolic alkalosis.
What process leads to release of insulin when someone is fed?
Glucose enters pancreatic beta cells, and is broken down into ATP. The ATP then binds to the ATP-sensitive K channel, depolarization occurs, and as a result the channel closes and insulin is released.
Which cells have increased glucose uptake (through increased receptors) as insulin levels increase?
Which cell types are independent?
Increased: Muscle cells, adipocytes.
Independent: Brain, kidney, intesting, liver, RBCs.
A patient with T2DM seems to have good control over their blood sugars (range between 100-180), yet they have an elevated A1C level. What should you suspect?
Beta thalassemia trait.
They don’t produce Hemoglobin A, so it throws off the reading? Something like that.
What do zinc finger motifs typically bind to? What type of hormones must they be attached to then?
The typically bind to intracellular receptors.
Thus, the hormones that express zinc finger motif must be intracellular–>steroid hormones, thyroid hormone, and fat-soluble vitamin receptors.
