Endocrine Week 2 Flashcards by Anum Samdani

Aldosterone actions

increased reabsorption of Na (and water), hypokalemia

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Substances that promote aldosterone excretion

potassium/hyperkalemia, ACTH

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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)

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Clinical presentation of primary hyperaldosteronism

hypertension and hypokalemia, age of onset <30 years

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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

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In unilateral aldosterone secretion, what are the levels of the contralateral adrenal venous blood like?

very low

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What is the difference between primary and secondary hyperaldosteronism?

Renin levels are increased in secondary while the levels are decreased in primary

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Patient presents with hypertension, hypokalemia, metabolic alkalosis, low renin activity, low aldosterone, normal plasma cortisol levels. What condition?

Apparent mineralocorticoid excess

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Deficiency in AME?

11-B HSD2 enzyme, converts cortisol to cortisone in kidney

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AME causes

hereditary, glycyrrhizic acid (licorice)

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Patient appears with hypertension, hypokalemia, low renin and aldosteronism. Appears like primary hyperaldosteronism.

Liddle Syndrome (treat with triamterene and amiloride)

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Common alpha agonist used in ICE, vasoconstriction and raises BP

phenylephrine

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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

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What neurotransmitter do adrenal medullary (chromaffin) cells mainly secrete?

epinephrine

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Pheochromocytomas (tumors of chromaffin cells) mainly secrete what? Paragangliomas (extra adrenal SNS ganglia) & metastases of pheos mainly secrete what?

epinephrine and norepinephrine

norepinephrine

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Classic symptoms of pheochromocytomas

hypertension, headaches, diaphoresis, palpitation, orthostatic BP changes

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What to test for to diagnose pheochromocytoma?

urinary catecholamines, plasma free metanephrines

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What can the secretion of large amounts of catecholamines from vesicles cause?

hypertensive crisis

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Best imaging test for pheochromocytomas?

CT scan of abdomen/adrenal glands

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Treatment for pheochromo?

A) alpha blocker (phenoxybenzamine)
B) then a beta blocker
C) hydration
D) adrenalectomy

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What mediates energy-dependent calcium absorption?

1,25(OH)2D

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Used to treat severe hyperparathyroidism

calcimimetic (cinacalcet)

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How are PTH and hypercalcemia related?

hypercalcemia is caused by increased PTH secretion and in turn suppresses PTH secretion

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PTH dependent hypercalcemia cause

primary hyperparathyroidism, familial hypocalciuric hypercalcemia

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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