Endocrine Flashcards
Normal migration of thyroid gland?
Thyroid gland is out pouching or pharyngeal epithelium that descends into the neck. Connected to tongue by thyroglossal duct. The foramen cecum is the dorsal surface of tongue and is a remnant.
Presentation of thyroglossal duct cyst?
Anterior midline neck mass that moves with swallowing o r tongue movt
Lingual thyroid
If only thyroid tissue present, removal could lead to hypothyroidism (in children lethargy, jaundice, feeding problems, constipation)
Congenital adrenal hyperplasia etios
21-hydroxylase deficiency - most common; dec. glucocorticoids and mineralocorticoids with increased adrenal androgens; 11B-hydroxylase - decreased glucocorticoids and inc. adrenal androgens; 17a-hydroxylase - nl mineralo, dec. androgens, estrogens, cortisols; 5a-reductase - defective conversion of testosterone to dihydrotestosterone (responsible for fusion); Side chain cleavage - conversion of chop to pregnenolone; impaired synthesis of all steroid hormones; Tx = low-dose corticosteriods to suppress ACTH secretion
MEN I
3 P’s - (hyper)Parathyroidism, Pancreas (gastrinoma -> peptic ulcer), Pituitary adenoma. Commonly presents with kidney stones + stomach ulcers.
Treatment for male pattern baldness?
5-alpha-reductase inhibitors (e.g. finasteride) b/c it is thought that enzyme in scalp doesn’t work that well
Salt-wasting v. non-salt-wasting 21-hydroxylase deficiency presentations
Girls - same; birth with ambiguous genitalia
Boys - Salt-wasting will present at 1-2 weeks with FTT, dehydration, hyperkalemia, and hyponatremia. Non-salt-wasting will present at 2-4 yrs with early virilization.
What enzyme converts Vitamin D into active form?
1-alpha hydroxylase. Resides in kidneys.
Adrenal gland subdivisions?
Cortex - zona glomerulosa (mineralocorticoids,aldo), zona fasciculata (glucorticoids, cortisol), zona reticularis (androgens); GFR = ACA
Medulla
Be wary of what side effects by which thyroid drugs?
Agranulocytosis by methimazole or PTU. WBC w/ diff for fever
Thyroid peroxidase?
Oxidation of iodide to iodine, iodination of thyroiglobuline tyrosine, and iodotyrosine coupling that forms T3, T4. TPO ab’s for Hashimoto’s.
Papillary carcinoma of thyroid FNA
Finely dispersed chromatic, ground-glass (Orphan Annie Eye), w/ intranuclear inclusions and grooves, and psammoma bodies.
Mech of hypoglycemia symptoms?
Inc. secretion of epinephrine and NE lead to sweating, tremor, palpitations, hunger, nervousness. CNS symptoms later b/c higher brain center activity decreases to conserve glucose -> behavior, confusion, stupor, seizures. Selective Beta-blockers preferable in diabetics b/c Beta-2 blockade leads to inhibition of gluconeogenesis, glycogenolysis, and lypolysis
Congenital Hypothyroidism
Lethargy, poor feeding, prolonged jaundice, constipation, hypotonia, hoarse cry. Pale, dry skin w/ myxedema, MACROglossia. Umbilical hernia. Higher incidence of ASD/VSD.
Neurophysin
Carrier proteins for oxytocin (paraventricular nuclei) and ADH (supraoptic nuclei) produced in hypothalamic nuclei. Help shuttle them to posterior pituitary. Mutation in neurophysin II for vasopressin thought to be cause of AD diabetes insipidus.
Path of Hashimoto’s?
Mononuclear, parenchymal infiltration w/ well-developed germinal centers
Pheochromocytoma rule of 10’s
10% occur as part of hereditary (MEN2, VHL), 10% b/l, 10% are extra-adrenal, 10% malignant. Tumor of chromatin tissue of adrenal medulla that increases production of NE and EPI.
Endogenous opioids?
Beta-endorphin is one derived from proopiomelanocortin (also precursor to ACTH). Stress axis ~ opioid.
Path findings in pancreas for DMT2?
Deposits of amylin (an amyloid) found in pancreatic islets. Theory: lead to beta cell apoptosis and defective insulin secretion
How to distinguish between where alkaline phosphatase is coming from?
Bone-specific Aphos is denatured by heat. Liver APhos does not.
Achondroplasia
AD. FGFR-3 point mutation leading to increased INHIBITION of cartilage proliferation. Normal trunk, shortened proximal extremities, enlarged head and frontal bossing.
Glucagonoma
Alpha-cells of pancreatic islets. Necrolytic migratory erythema, Hyperglycemia.
VIPoma
Intractable diarrhea, metabolic acidosis, hypokalemia
Somatostatinoma
Tumor of pancreatic delta-cells. Abdominal pain, gallbladder stones, constipation, steatorrhea. 2/2 to somatostatin’s inhibitory effects of insulin, glucagon, gastrin, cholecystokinin, and secretin secretion.