Flashcards
UWorld Endocrinology
Cards in this deck (87)
- 1Prolactinoma-suppressed GnRH --> hypogonadism and bone loss
- 2Inhibin B-Sertoli cells secrete inhibin B which provides negative feedback to FSH
-pts w/ one testes i.e. undescended have a reduced sertoli mass --> decreased inhibin B --> increased FSH
-Leydig cells more likely to compensate in 1 teste scenarios - 3#Medullary thyroid cancer-from parafollicular calcitonin secreting C cells
#-nests/sheets of polygonal or spindle shaped cells w/ EC amyloid deposits that stain Congo red (excess calcitonin)
-derived from neural crest cells - 4#Thiazolidinediones-act PPAR y --> upreg genes i.e. glut4 and adiponectin (fat cytokine that increased number of insulin sensitive adipocytes)
-takes longer to have effect bc changes gene expression - 5#Metformin-noncompetitive inhibitor of mitochondrial glycerol 3 P dehydrogenase which maintains the hepatic redox state
-inhibits complex 1 of the electron transport chain
-decrease in energy stores act AMPK --> decr hepatic gluconeogenesis
-due to shift to anaerobic conditions and lack of gluconeogenesis --> build up of lactic acidosis
-avoid in CHF and alcoholic who tend to have high lactic acidosis - 6#MOTEL PASS (cells on the move)-neural crest cell derivative
M: melanocytes
O: odontoblasts
T: tracheal cartilage
E: enterochromaffin cells
L: laryngeal cartilage
P: parafollicular cells
A: adrenall medulla/all ganglia
S: schwann cells
S: spiral membrane - 7Beta blockers and thyroid storm-thyrotoxicosis cause increase in beta R expression --> increased sensitivity to catecholamines
-beta blockers reduce HR and anxiety while also inhibiting iodothyronine deiodinase --> decreased peripheral conversion of T4 --> T3 - 8Hashimoto's thyroiditis-intense mononuclear infiltrate w/ lymphocytes and plasma cells, often with germinal centers
-residual follicles surrounded by Hurthle cells (oxyphilic cells w/ granular cytoplasm) = follicular epithelial cells that have undergone metaplasia in response to inflammation - 9#Hormone sensitive lipase-activated by stress hormones i.e. catecholamines, glucagon, ACTH
-Gs --> cAMP --> PKA --> act of HSL and lipolysis --> glycerol (used for gluconeogenesis) and FFAs (ketone bodies)
-will show fasting glucose levels and urine ketones - 10Phenylethanolamine N methyl transferase-converts NE to epinephrine
-stimulated by cortisol - 11#Glucocorticoid#-promote gluconeogenesis and glycogenesis --> overall increase in glucose
-catabolic --> myopathy and proximal muscle weakness
#-decr GI ca absorption, incr renal ca excretion, and direct inhibition of osteoblasts
-induce T cell apoptosis but demarginate neutrophils (incr release from BM)
-inhibit fibroblasts in the skin --> striae and impaired wound healing - 12#Insulin resistance-elevated free fatty acids cause insulin R but not low HDL or high LDL
- 13#Gynecomastia-ductal epithelial hyperplasia surrounded by dense stromal fibrosis
Causes:
-hyperthyroid increases LH and estrogen production
-CKD: decreases testosterone production
-tamoxifen effective for prevention in androgen deprivation therapy - 14#Danazol bicalutamide-danazol: androgenic and antiestrogenic but at high doses can suppress gonadotropins/androgen; also assoc w/ risk of rapid prostate growth
-bicalutamide: antiandrogen that can block flare in prostate cancer growth in pts taking long acting GnRH agonists but can incr gynecomastia - 15ADH secretion-SIADH in carbamazepine, cyclophosphamide, and SSRIs
-stored in Herring bodies, co secreted w/ neurophysins (post-translational hormone processing and stabilization during axonal transport)
#-mut in neurophysin --> AD hereditary hypothalamic diabetes insipidus - 16Craniopharyngioma-develops from remnants of Rathke's pouch
-3 components: solid tumor cells, cystic space filled w/ machine oil like substance, and calcifications
-usu affects 5-10 y/o
-can also lead to hypopit or hyperprolactin - 17#CNS symptoms of hypoglycemia1) neurogenic (ANS): tremulousness, palpitations, anxiety/arousal (NE/EPI) + sweating, hunger, and parasthesias (ACh)
2) Neuroglycopenic: behavior changes, confusion, visual disturbances, stupor, and seizures
-careful w/ B blockers --> use B1 selectives (pinolol, acebutolol) - 18#Liver and ketone use-liver also unable to use ketones for energy bc lacks succinyl CoA-acetoacetate CoA transferase necessary to convert acetoacetate to acetoacetyl CoA
- 19#Hypothyroid myoedema-focal mounding of muscle following percussion
-myalgia, proximal muscle weakness, and cramping
#-secondary to slow reabsorption of calcium by the sarcoplasmic reticulum
-CK will be elevated and can precede overt symptoms - 20#Regular insulin and NPH-only recombinant insulins that are not modified w/ amino acid
-regular insulin can be given subQ for long term management but should not be used in DKA bc these pts are volume depleted and have erratic subQ absorption - 21#insulin modifications-rapid acting: amino acid modifications prevent polymerization --> more rapid absorption
-NPH: w/ protamine and zinc --> delay of absorption
-Detemir: fatty acid bound to a lysine --> binds to albumin --> slow dissociation
-Glargine: pH of 4 --> subQ microprecipitate --> slow release and no pronounced peak - 22#Brown adipose tissue-tan fat containing tissue around the kidneys and adrenal glands in newborns
-necessary bc babies have immature CNS and cannot shiver
-contain several fat vacuoles, more mitochondria, and more blood vessels than white adipocytes
-thermogenin membrane protein that allows protons to return (uncoupled oxidative P'ation) - 23#TNF alpha and insulin R-activates serine kinases which P'ate serine residues on the IC beta subunits of insulin R and insulin substrate 1 --> decr downstream signalling
-similar mech w/ threonine p'ation and other signals i.e. catecholamines, glucocorticoids, and glucagon - 24Hypomagnesemia-can occur due to severe diarrhea
-can cause hypoPTH - 25Radioactive Iodine incident-can accumulate in thyroid and cause hypothyroid or cancer
-use potassium iodide to competitively inhibit the Na-I symporter (occurs most rapid)
-iodide also inhibits iodine organification (Wolff-Chaikoff effect) - 26Calcium sensing Rs-G protein coupled R's in parathyroid gland and in the kidneys
- 27Hormones and R types-nuclear Rs: steroids, thyroid, and vitD
-Janus kinase Rs: GH, prolactin, and EPO - 28#Pompe disease-deficiency of acid alpha glucosidase/acid maltase which breaks down glycogen in acidic enviro of lysosomes
-most glycogen broken down in cytosol but in excess --> backs up in lysosomes esp in hepatocytes and myocytes --> cardiomegaly, hepatomegaly, macroglossia
-blood glucose is normal
-accumulation of glycogen in lysosomes is pathognomonic
-acid pumps trash the pump (heart) - 29#ATP citrate lyase-acetyl CoA generated in mito converted to citrate and transferred to cytosol
-citrate lyase converts citrate back into acetyl CoA to be used for fatty acid chain elongation - 30#DiGeorge's syndrome#-neural crest cells fail to migrate to 3rd (inferior parathyroid and thymus) and the 4th pouches (superior parathyroid)
- 31Hyocalcemia signs1) Chvostek sign: tap on facial n --> twitching of the nose and lips
2) Trousseau sign: inflation of the bp cuff --> carpal spasm - 32#Iodothyronine deiodinase vs iodotyrosine deiodinase-thyronine: in periphery --> removal of iodine from T4 --> T3
-tyrosine: in the thyroid follicular cell; iodine groups removed from DIT or MIT for recycling - 33#Heparin and familial chylomicronemia syndrome-LPL normally bound on heparin sulfate moieties on vasc endothelium
-heparin releases LPL decreasing its activity - 34#Glucagonomahyperglycemia, anemia, and necrolytic migratory erythema (raised rash on face, groin, and extremities)
-rash lesions enlarge and coalesce leaving central indurated area w/ peripheral blistering and scaling
- 35#Gluconeogenesis-uses a lot of same enzymes from glycolysis but needs to bypass unidirectional hexokinase, phosphofructokinase, and pyruvate kinase
-pyruvate --> oxaloacetate --> malate shuttle --> oxaloacetate --> phosphoenolpyruvate
-other unique enzymes: phosphoenolpyruvate carboxykinase (uses GTP), fructose 1,6 bisphosphatase, and glucose 6 phosphatase - 36#Leptin and PPAR y-leptin actually decreases or remains unchanged in glitazones bc PPARy inhibits leptin gene transcription (does cause weight gain)
- 37#Ornithine transcarbamylase deficiency-most common urea cycle disorder
-forms citrulline from ornithine + carbamoyl phosphate
-defect leads to excess carbamoyl phosphate which shunts to pyrimidine syn --> increased excretion of orotic acid
-pts also have hyperammonia and tachypnea/resp alkalosis - 38#Zinc finger-DNA binding domain
-bind to zinc via cysteine and histidine (the C-histine chapel - God w/ finger to Adam)
-2 antiparallel beta strands w/ alpha helix in the middle - 39Diabetes pathogenesis-Type II: amyloid polypeptide (amylin) co-secreted w/ insulin is deposited and may cause beta cell apoptosis
-Type I: gene polymorphism in HLA-DR and HLA-DQ (high prevalence of DR3 and DR4 haplotypes) - 40#Adrenal insufficiency-atrophy due to chronic glucocorticoid use --> cortisol cannot rise in stressful event i.e. surgery or infection
#-glucocorticoids help maintain NE, renin, and angiotensin --> hypoTN and shock (#also nausea, vomiting, abdom pain, weakness, and fever)
-need higher stress dose
-tx for adrenal crisis: IV fluids and hydrocortisone or dexamethasone - 41Preterm baby-i.e. in scenario of rupture placenta
-need to give corticosteroids to mature type II pneumocytes, incr surfactant production, and prevent ARDS - 42#Exercise induced hypoglycemia-diabetics taking insulin are at risk bc insulin is exogenous and will continue even when glucose falls
#-GLUT-4 translocation in muscle also mediated by contraction (insulin-indep) [AMP kinase, NO, and ca-calmodulin protein kinase
-infection, pain, and sleep deprivation tend to cause hyperglycemia due to act of catecholamines --> glycogenolysis and gluconeogenesis - 43#Fructokinase deficiency-essential fructosuria is benign
#-hexokinase takes over instead making fructose 6 P which is used in glycolysis (instead of being made into fructose 1 P --> aldolase B)
-can't really use this in aldolase B deficiency bc already made fructose 1 P [default] and can't get rid of it - 44Hypothyroid crisis-hypoglycemia, hypotension, AMS, hypothermia, bradycardia, and hypoventilation
-would be tachycardic in adrenal crisis
-levothyroxine has long half life and missing couple days unlikely to provoke this - 45#Maturity onset diabetes of the young-mild nonprogressive hyperglycemia that worsens w/ insulin R in pregnancy
-heterozygous mut in glucokinase gene (also in pancreatic beta cells that helps to sense glucose, make ATP, block K channels, and secrete insulin)
-homozygous --> fetal growth retardation, severe hyperglycemia at birth - 46Glycolytic enzyme deficiencies-aldolase A, enolase, phosphofructokinase, pyruvate kinase
-usu causes hemolytic anemia bc RBCs rely solely on glycolysis (also insulin indep glucose uptake) - 47#Thyroid hormone levels-in low T4, T3 usu normal until late stage bc levels fluctuate and short half life
#-increase in TBG due to preg or OCP use --> increase total hormone but normal free hormone (euthyroid and normal TSH) - 48Anastrozole, letrozole, exemestane-aromatase I's
-aromatase in p450 family and is gonadotropin dependent in ovarian tissue and also in adrenal cortex, fat tissue, and breast
-in menopause, ovaries and adrenal glands still produce androgens which gets converted to estrogen by extraovarian aromatase - 49#5 alpha reductase#-type I is found in postpubescent skin and type II found in genitals
#-def in type II --> normal internal male genitalia (due to T) but abnormal external genitalia due to lack of DHT
-at puberty, rise in T and activity of type I increases muscle mass, deepens voice, and causes penile/scrotal growth and testicular descent
-DHEA sulfate weak androgen made in adrenal glands, def does not undervirilize - 50oral glucose tolerance test-preferred screening for gestational diabetes and CF related diabetes
-can also be used when other results unclear
-not overall preferred bc more expensive and less convenient - 51reverse T3-converted from T4 NOT T3
- 52Niemann-Pick disease-lipid laden foam cells accumulate in the liver, spleen, and CNS --> hepatosplenomegaly, hypotonia, and neurodegeneration
-infants fail to learn and lose milestones
-retinal accumulation --> cherry red macular spot
-death usu by age 3 - 53#Dysostosis multiplex-Hurler syndrome
-enlarged skull and abnormally shaped ribs and vertebrae - 54#Papillary thyroid cancer-most common
#-overlapping nuclei w/ finely dispered chromatin (ground glass/Orphan annie)
#-intranuclear inclusions and grooves due to invagination of nuclear membrane - 55Follicular adenoma vs follicular cancer-cannot be determined by FNA
-need to see capsular or capillary invasion
-can also use gene expression analysis - 56#Anaplastic thyroid cancer#Pleomorphic cells, irregular giant cells, and biphasic spindle cells
- 57Mitochondrial DNA-1-10 copies of maternally derived mtDNA in each mitochondrion
-most of them migrated to nuclear DNA
-small circular chromosome encoding oxidative metabolic pathways and rRNA/tRNA necessary for mitochondrial protein syn - 58#Gluconeogenesis fun facts-epinephrine actually decreases glucose uptake by skeletal muscle; also increases alanine release from skeletal muscle
-in sustained fasting, renal cortex can actually join gluconeogenesis (more stimulated by epinephrine than glucagon)
-glucagon actually stimulates insulin secretion to increase glucose uptake - 59Tx of hypoglycemia-self treated w/ oral glucose
-medical setting unconscious --> IV glucose
-nonmedical setting --> IM or subQ glucagon (10-15 mins recovery)
-buccal and sublingual is slow and erratic - 60Metyrapone stimulation test-blocks cortisol syn by inhibiting 11 beta hydroxylase --> incr ACTH due to lack of neg feedback --> incr production of 11 deoxycortisol and 17 OH corticosteroids which accumulate in the urine
-failure of these steroids to increase indicate a primary or secondary adrenal insufficiency (distinguish w/ ACTH levels) - 61Causes of acute hypocalcemia-most common = injury to parathyroid glands
-others: autoimmune hypoparathyroid, sepsis, tumor lysis syndrome, acute pancreatitis, severe vitD or magnesium deficiency - 62#Debranching enzyme deficiency-Cori disease
#-hypoglycemia, hepatomegaly, ketoacidosis
#-muscle and liver involvement (hypotonia helps distinguish from von Gierke bc glucose 6 phosphatase not rly in muscle)
#-hepatic fibrosis but not really fatty infiltrate like in von Gierke
-cytosolic accumulation of glycogen w/ abnormally short outer chains (limit dextrans) - 63#Hers disease-liver glycogen phosphorylase deficiency
-presents in early childhood w/ hypoglycemia, ketosis, and hepatomegaly
#-excess of normal glycogen in liver bx, does not affect muscles - 64Urine dipstick-detects glucose but not galactose or fructose
-all of these sugars are reducing - 65#Apolipoproteins-ApoE3 and ApoE4 = familial dysbetalipoproteinemia
-ApoA1 = works w/ LCAT in esterification of cholesterol - 66#Euvolemia states-primary polydipsia and SIADH
-retain free water causing hypo-osmolarity but volume is euvolemic bc ECF volume is regulated by aldosterone and natriuretic peptides
-ICF is expanded though - 67GLUT2-facilitates glucose export from the liver, kidney, and small intestine
-also controls insulin secretion in the pancreas - 68#MEN 2B-medullary thyroid CA, pheo, and mucosal neuromas/marfanoid body habitus
#-mucosal neuromas = flesh colored nodules, unencapsulated + thickened proliferations of neural tissue
-can also have intestinal ganglioneuromas --> constipation - 69#Maple syrup urine disease-neurotoxicity due to incr buildup of leucine --> progressive irritability, poor feeding, lethargy, and incr muscle tone
-still danger even after diet restriction - 70Incretins-GI hormones that stimulate insulin secretion in response to sugary meals
-include GLP-1 and GIP (glucose dependent insulinotropic protein)
-cause higher insulin levels w/ oral glucose vs IV glucose - 71#Somatomedin C= insulin GF-1
- 72Cushing disease vs ectopic ACTH-different in that ectopic will not even be suppressed when given high dose dexamethasone
- 73GsPTH, ACTH, TSH, ADH V2
- 74GqGnRH, TRH, angiotensin II, and ADH V1
- 7511 beta hydroxylase deficiency-2nd most common cause of CAH
-usu converts 11 deoxycorticosterone into corticosterone
-females will be virilized but will have a low renin hyperTN and hypokalemia bc 11 deoxycorticosterone (a weak mineralocorticoid) accumulates - 76Glyburide vs glipizide-rides are longer acting and have a higher risk of hypoglycemia than glipizide
- 77#Ornithine decarboxylase-involved in DNA stabilization and repair
-inhibition leads to decreased cell growth and increased apoptosis
-eflornithine topical inhibitor used to decrease the rate of facial hair growth - 78Impaired beta oxidation-hypoketotic hypoglycemia
-most common def is in acyl CoA dehydrogenase (R group not CH3) which catalyzes reactions inside mitochondria
-normally generates FADH2, NADH, and acetyl CoA for CAC or ketogenesis
-primary carnitine deficiency can also interrupt transport of fatty acids into mitochondria --> muscle weakness, cardiomyopathy, hypoketotic hypoglycemia, elevated muscle TGs - 79Insulin signalling-act MAPK pathway --> DNA syn and cell growth
-act of PI3K --> translocation of Glut4, glycogen and fat syn
-PI3K activates protein phosphatase which deP'ates glycogen synthase --> activation - 80PTH-PTH Rs on osteoblasts not osteoclasts --> upreg RANK ligand and decr OPG
- 81Hyperglycemia induced tissue damage-glucose nonezymatically glycosylates proteins and lipids and can stabilize into irrev products --> AGEs accumulate and facilitate LDL deposition and inflammation --> atherosclerosis and microangiopathic complications
-accumulation of sorbitol increases osmotic cellular injury
-aldose reductase uses up NADPH to make sorbitol --> depleting it and increasing ROS - 82#Biotin-needed for carboxylase reactions (gluconeogenesis and fatty acid synthesis)
-deficiency (consumption of excess egg whites) --> AMS, myalgias, anorexia, and chronic macular dermatiits
-metabolic acidosis due to incr lactate - 83#-glinides-shorter acting than sulfonylureas and less risk of hypoglycemia
- 84#Ankle sprain-lateral ankle sprain usu due to inversion of a plantar flexed foot
-stabilized laterally by anterior inferior tibiofibular, anterior talofibular, posterior talofibular, calcaneofibular ligaments
-lateral ankle ligaments are weaker and more prone to injury - 85Niacin and goutdecreases renal excretion of uric acid
- 86#Digital clubbing-unclear: platelet precursors fail to fragment completely w/in pulm circulation --> incr megakaryocytes and clumps in periphery --> impact in fingers/toes --> incr in VEGF and PDGF --> clubbing
-also assoc w/ incr prostaglandin E2 - 87#Klinefelters-most common cause of hypogonadism
-progressive destruction/hyalinization of seminiferous tubules --> small, firm testes
-inhibin decreased and low T due to dysfunction Sertoli and Leydig cells --> lack of feedback inhibition --> incr FSH and LH --> incr aromatase and estrogenization
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- Flashcards on UWorld Endocrinology, created by Amanda Le on 04/05/2017.
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