Endocrine Week 2 Flashcards
Aldosterone actions
increased reabsorption of Na (and water), hypokalemia
Substances that promote aldosterone excretion
potassium/hyperkalemia, ACTH
What happens to renin concentration and activity in these drugs: A) Aliskiren B) ACE inhibitors C) ARBS D) Mineralcorticoid receptor antagonists
A) renin concentration increased, activity decreased
B) renin concentration and activity increased (+ hyperkalemia)
C) renin activity increase (+hyperkalemia)
D) renin levels increase (+hyperkalemia)
Clinical presentation of primary hyperaldosteronism
hypertension and hypokalemia, age of onset <30 years
What is the plasma aldosterone:renin ratio in patients with primary hyperaldosteronism?
Aldosterone level is increase (>12) and renin activity is suppressed (<1) and so the ratio is elevated
In unilateral aldosterone secretion, what are the levels of the contralateral adrenal venous blood like?
very low
What is the difference between primary and secondary hyperaldosteronism?
Renin levels are increased in secondary while the levels are decreased in primary
Patient presents with hypertension, hypokalemia, metabolic alkalosis, low renin activity, low aldosterone, normal plasma cortisol levels. What condition?
Apparent mineralocorticoid excess
Deficiency in AME?
11-B HSD2 enzyme, converts cortisol to cortisone in kidney
AME causes
hereditary, glycyrrhizic acid (licorice)
Patient appears with hypertension, hypokalemia, low renin and aldosteronism. Appears like primary hyperaldosteronism.
Liddle Syndrome (treat with triamterene and amiloride)
Common alpha agonist used in ICE, vasoconstriction and raises BP
phenylephrine
What physiological response should you be wary of when combining alpha and beta blockers?
Alpha blockers cause reflex tachycardia–use together leads to large BP lowering
What neurotransmitter do adrenal medullary (chromaffin) cells mainly secrete?
epinephrine
Pheochromocytomas (tumors of chromaffin cells) mainly secrete what? Paragangliomas (extra adrenal SNS ganglia) & metastases of pheos mainly secrete what?
epinephrine and norepinephrine
norepinephrine
Classic symptoms of pheochromocytomas
hypertension, headaches, diaphoresis, palpitation, orthostatic BP changes
What to test for to diagnose pheochromocytoma?
urinary catecholamines, plasma free metanephrines
What can the secretion of large amounts of catecholamines from vesicles cause?
hypertensive crisis
Best imaging test for pheochromocytomas?
CT scan of abdomen/adrenal glands
Treatment for pheochromo?
A) alpha blocker (phenoxybenzamine)
B) then a beta blocker
C) hydration
D) adrenalectomy
What mediates energy-dependent calcium absorption?
1,25(OH)2D
Used to treat severe hyperparathyroidism
calcimimetic (cinacalcet)
How are PTH and hypercalcemia related?
hypercalcemia is caused by increased PTH secretion and in turn suppresses PTH secretion
PTH dependent hypercalcemia cause
primary hyperparathyroidism, familial hypocalciuric hypercalcemia
Primary hyperparathyroidism findings
increased/normal PTH, hypercalcemia, hypophosphatemia
FHH symptoms
most asymptomatic, PTH not suppressed, CaSR mutation
Causes for PTH-independent hypercalcemia
malignancy, calcitriol-mediated, hyperthyroidism
First measure what in hypercalcemia?
PTH, if elevated, most likely primary hyperparathyroidism
treatment of hypercalcemia
saline, furosemide, calcitonin, bisphosphonates
Clinical exams for hypocalcemia
Chvostek’s, Trousseau’s
Treatment hypocalcemia
calcium supplements, vitamin D2/D3/calcitriol
FGF23 and phosphate in the body
excess cause hypophosphatemia, decrease causes hyperphosphatemia
What is the primary function of cortical bone? trabecular?
cortical: structural function
trabecular: metabolic
Activators of osteoclast activity
PTH
1, 25 di-OH vitamin D
What part of the bone is good for resisting compressive loads? Tensile?
Compressive: mineral
Tensile: protein
Primary protein component of bone
type 1 collagen
Most common sites of low trauma fractures
spine, distal radius (Colles’ or wrist fractures), and hip
pelvis, proximal humerus
What DXA T-score suggest that a patient might have osteoporosis?
T<-2.5
What is the single most powerful predictor of future fracture?
past fracture
Fracture risk factors
age, sex, glucocorticoid use
Differentiate between osteomalacia and osteoporosis
in the latter, quantity of bone matrix insufficient, architecture impaired
What is elevated in serum in osteomalacia?
PTH, TNSALP, P1NP
Drugs to treat osteoporosis
Estrogen/receptor: tomxifen, raloxifene
Bisphosphonates: -dronate
RANKL decoy receptor: Denosumab
Anabolic: Teriparatide (PTH fragment)
What substrate in phostphate metabolism is associated with osteomalacia?
FGF23
Most common pituitary tumor
prolactin
postpartum pituitary necrosis cause by ischemia of pituitary gland
Sheehan syndrome
Cells in the adrenal medulla? What is secreted there?
chromaffin cells
secrete cathecholamines
Inherited causes of adrenocortical carcinoma
Li-Fraumeni syndrome (p53), Beckwith-Wiedmann syndrome (ch11 at WT2 locus)
Pheochromocytoma rule of 10s
10% associated with familial syndromes, 10% extraadrenal, 10% bilateral, 10% malignant
Adrenal cortical atrophy is most likely caused by ___(A)____? Bilateral hyperplasia is most commonly associated with ____(B)___?
A) exogenous steroids
B) endogenous Cushings’
Most common cause of primary hyperparathyroidism
parathyroid adenoma
Name the organ that is experiencing dysfunction:
(A) Primary hypothyroidism
(B) Secondary hypothyroidism
(C) Tertiary hypothyroidism
(A) thyroid gland (T4/T3)
(B) pituitary gland (TSH)
(c) hypothalamus (TRH)
Most common cause of primary hypothyroidism
Hashimoto’s thyroiditis (chronic lymphocytic thyroiditis)
Drugs that cause secondary hypothyroidism
dopamine, glucorticoids
Drugs that cause primary hypothryoidism
antithyroid agents, lithium
Most common thyroid hormone supplement provided?
Levothyroxine (T4)
Liothyronine (T3) available but not widely given
How long to wait before adjusting thyroid hormone dose?
5-6 half lives
1 half life is 7 days
Most common cause of primary hyperthyroidism?
Graves’ disease
Secondary is very rare–TSH secreting pituitary adenoma
Driving force for thyrotoxicosis in primary hyperthyroidism?
thyroid stimulating immunoglobin
What step should be taken after a TSH in order to diagnose betweeb different causes of hyperthyroidism?
radioactive iodine
Main treatments of Graves’ disease
methimazole and propylthiouracil (inhibitors of thyroidal organification)
radioactive iodine
surgery
Other meds to treat hyperthyroidism
Logul’s solution (oral iodine)
propanolol
cholestyramine
Most common reason for congenital hypothyroidism in the world?
iodine deficiency
Most common reason for congenital hypothyroidism
dysgenesis
Most states test what in order to screen for congenital hypothyroidism?
high values TSH
By what age does having hypothyroidism not affect mental function?
3 years
Most common thyroid lesion-variable sized nodules with increased colloid, unencapsulated
nodular goiter
Massive infiltration of lymphocytes with germinal center formation, Hurthle cell change (abundant cytoplasm)
Hashimoto’s Thyroiditis
Granulomatous (giant cell) inflammation
Subeacutethyroiditis
Follicular cells with scalloped colloid
Graves’ disease
Uniform follicle pattern, capsule present
follicular adenoma
Follicles but with capsular invasion
follicular carcinoma
Orphan Annie clearing, psuedoinclusion
papillary carcinoma
Nests and cords of cell in amorphous pink amyloid stroma
medullary carcinoma
Pleiomorphic giant tumor cells, spindle cells
anaplastic carcinoma
Fine needle aspirates are diagnostic for which diseases?
papillary carcinoma, medullary carcinoma
Which transporter is the major insulin responsive glucose transporter found mostly in skeletal/cardiac muscle and fat?
GLUT4
What substances stimulate glucose secretion?
glucose, amino acids, fatty acids, indirectly GH/cortisol
What substance amplifies insulin?
GI hormones
What inhibits insulin secretion?
somatostatin (paracrine)
Which has a longer time course-regular or NPH insulin?
NPH (cloudy suspension)
What is the longest acting insulin analog?
insulin glargine
Why should metformin not be prescribed to patients with renal insufficiency?
side effect of lactic acidosis
What target does metformin make more sensitive to insulin? Thiazolidinediones (-glitazone)?
Liver
Fat and Muscle (PPAR)
What transporter leads glucose to enter the pancreatic beta cell?
GLUT2
What are the microvascular long term complications of diabetes mellitus?
retinopathy, nephropathy, neuropathy
What are the macrovascular complications of diabetes mellitus?
coronary artery disease, peripheral vascular disease
