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97 Cards in this Set
- Front
- Back
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What and where is the macula densa?
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Group of densely packed cells of the distal tubular epithelium that act as chemoreceptors and feed information to the JGA, which is directly apposed.
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What is the JGA?
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Juxtaglomerular Apparatus, part of the afferent arteriole of the glomerulus that secretes renin in response to decreased blood pressure sensed by the kidney.
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Besides the kidneys, what other structures are retroperitoneal at their level?
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- parts of the duodenum
- part of the pancreas - Aorta - IVC - ascending & descending colon - adrenal glands - rectum |
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The ureters pass under/over the uterine artery, and under/over the vas deferens.
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under; under
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For a 100 kg man, how many liters of total body water does he have?
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60 L (60% of total body wt.)
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For a 100 kg man, what is the volume of intracellular fluid he has?
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40 L (40% of total body wt.)
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For a 100 kg man, what is the volume of extracellular fluid he has?
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20 L (20% of total body wt.)
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For a 100 kg man, what is the volume of plasma in his body?
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5 L (5% of total body wt.)
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What percent of your total body weight is interstitial volume?
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15%
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What do you use to measure extracellular fluid volume?
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inulin - a polysaccharide
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What do you use to measure plasma volume?
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radiolabelled albumin
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What is the formula for renal clearance of a substance?
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C = (U*V)/P where U is urine concentration of substance, V is urine flow rate, and P is plasma concentration of substance.
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If clearance is < GFR:
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there is net reabsorption of substance
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If clearance = GFR:
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there is no net reabsorption or secretion of substance
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If clearance > GFR:
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there is net secretion of substance
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What 3 things make up the glomerular filtration barrier?
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1) fenestrated capillaries (size barrier)
2) heparan sulfate (- charge barrier) 3) podocyte foot processes |
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What is lost in nephrotic syndrome and what does that lead to?
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charge barrier (and podocyte foot processes) - albuminuria, hypoproteinemia, hyperlipidemia, generalized edema
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GFR is calculated by using clearance of:
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inulin - freely filtered, neither reabsorbed nor secreted by kidneys
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How can you calculate GFR using hydrostatic pressures and oncotic pressures?
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Kf * [(Pgc - Pbs) - (Onc gc - Onc bs)], where gc = glomerular capillary and bs = bowman's space
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What is PAH used for?
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Clearance of para-aminohippuric acid is used to estimate Effective Renal Plasma Flow, because it is filtered and actively secreted by the kidney. True Renal Plasma Flow is 10% greater than this estimate, however.
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What is "clearance?"
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VOLUME of plasma from which a substance is cleared completely per unit time
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How do you calculate Renal Blood Flow?
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RBF = RPF/(1-Hct)
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Prostaglandins preferentially ___ the afferent arteriole. Your RPF ___, GFR ___, so filtration fraction ___.
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dilate; increases, increases, remains constant
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Filtration Fraction =
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GFR/RPF
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AII preferentially ___ the efferent arteriole. Your RPF ___, GFR ___, so filtration fraction ___.
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vasoconstricts; decreases, increases, increases
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How does constricting the ureter affect RPF, GFR, and FF?
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no change; decrease, decrease
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At what level of plasma glucose does glucosuria begin?
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200 mg/dL
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At what plasma level of glucose is the glucose transport mechanism saturated?
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350 mg/dL
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What happens in the proximal convoluted tubule?
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Reabsorb most of bicarb, glucose, AA, Na, water. Secrete ammonia which acts as buffer for secreted protons.
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What happens in the thin descending limb?
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Passive reabsorption of water. Is impermeable to Na+.
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What happens in the thick ascending limb?
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Active reabsorption of Na/K/Cl via NKCC cotransporter. Indirect reabsorption of calcium & magnesium. Is impermeable to water.
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What happens in the distal convoluted tubule?
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Active reabsorption of NaCl via Na/Cl cotransporter. PTH acts here to reabsorb calcium.
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What happens in the collecting tubules?
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Aldo acts to reabsorb Na+ in exchange for K+ and H+ secretion. ADH acts to reabsorb water.
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What are 4 functions of AII?
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1) vasoconstriction
2) aldo release from zona glomerulosa of adrenals 3) ADH release from posterior pituitary 4) stimulate hypothalamus (supraoptic nucleus) --> thirst --> drink water |
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What does renin do? What stimulates its release?
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Released by JG cells in response to low BP & low Na+ delivery to distal tubule & increased sympathetics, and cleaves angiotensinogen to AI, which is then cleaved by ACE to AII.
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How does the kidney respond to hypoxia?
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Endothelial cells of peritubular capillaries make EPO.
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What does the kidney have to do with calcium?
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Has enzyme 1-a-hydroxylase to make 1,25(OH)2 vitamin D for gut calcium absorption. Enzyme is activated by PTH.
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What does the kidney make to vasodilate the afferent arterioles?
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PG's - vasodilate afferent to increase GFR
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How can NSAIDs cause acute renal failure?
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If someone is in a vasoconstrictive state, the inhibiton of PG synthesis by NSAIDs can cause vasoconstriction of afferent arteriole and a drop in GFR.
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How do you calculate pH if given the pKa, [HCO3], and PCO2?
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Henderson-Hasselbach equation:
pH = pKa + log([HCO3]/0.03*PCO2) |
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A patient comes in with a blood pH of 7.2. His PCO2 > 40mmHg. What could possibly be wrong with this man?
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Respiratory acidosis, caused by hypoventilation. Could be airway obstruction, lung disease, opioid overdose, weak respiratory muscles.
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A patient comes in with a blood pH of 7.2 and a PCO2 < 40mmHg. What do you want to know next?
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He is in metabolic acidosis with respiratory compensation. You want to know if there is an increased anion gap to narrow down DDx.
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What are causes of metabolic acidosis with increased anion gap?
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M- methanol
U- uremia D- diabetic ketoacidosis P- paraldehyde, phenformin I- iron, INH L- lactic acidosis E- ethylene glycol S- salicylates |
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What are causes of metabolic acidosis with normal anion gap?
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diarrhea, glue sniffing, RTA, hyperchloremia
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Someone hyperventilating will end up in respiratory/metabolic acidosis/alkalosis.
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respiratory alkalosis (pH > 7.4 with PCO2 < 40mmHg)
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What can cause metabolic alkalosis? What is the blood pH and PCO2 profile with respiratory compensation?
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pH > 7.4; PCO2 > 40
vomiting, diuretics, antacid, hyperaldosteronism |
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How do you calculate if the PCO2 is compensated for in metabolic acidosis?
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Winter's formula:
PCO2 = 1.5(HCO3) + 8 (+/- 2) |
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Metabolic alkalosis compensation: PCO2 increases ___ for every 1 mEq/L increase in bicarb
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0.7
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Acute respiratory acidosis compensation:
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increase 1:10 (bicarb:PCO2)
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Chronic respiratory acidosis compensation:
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increase 3.5:10 (bicarb:PCO2)
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Acute respiratory alkalosis compensation:
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decrease 2:10 (bicarb:PCO2)
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Chronic respiratory alkalosis compensation:
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decrease 5:10 (bicarb:PCO2)
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What is Potter's Syndrome?
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bilateral renal agenesis (malformation of ureteric limb bud) --> oligohydramnios --> limb deform, face deform, pulmonary hypoplasia
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RBC casts in urine =
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glomerular inflammation (nephritic syndrome), malignant HTN, ischemia
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WBC casts in urine =
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tubulointerstitial disease, acute pyelonephritis, glomerular disorders
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Granular casts =
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acute tubular necrosis!
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Waxy casts =
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chronic renal failure
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Bladder cancer --> see ___
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RBCs
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Acute cystitis --> see ___
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WBCs
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Describe 4 features of nephritic syndrome:
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1) hematuria
2) HTN 3) azotemia 4) oliguria |
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Name the 6 conditions that give you nephritic syndrome:
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1) acute post-streptococcal
2) rapidly progressive (crescentic) 3) Goodpasture's 4) Membranoproliferative 5) IgA (Berger's) 6) Alport's syndrome |
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Nephrotic syndrome is characterized by:
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1) proteinuria
2) hypoalbuminemia 3) hyperlipidemia 4) peripheral/periorbital edema |
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Name 5 nephrotic syndromes:
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1) membranous
2) focal segmental glomerular sclerosis 3) minimal change disease 4) diabetic nephropathy 5) SLE membranous glomerulonephritis |
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What can renal cell CA's secrete?
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1) EPO
2) ACTH 3) PTH 4) prolactin |
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How does renal cell CA present?
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hematuria, flank pain, fever, wt. loss, palpable mass, secondary polycythemia
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What 2 things increase risk of renal cell CA?
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smoking, obesity
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Who most often gets renal cell CA?
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men 50-70 yrs, also associated with von Hippel-Lindau (VHL gene deletion ch3; recall hemangioblastomas of retina/cerebellum/medulla)
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Ammonium magnesium phosphate kidney stones are caused by:
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urease positive organisms (Proteus, Staph, Klebsiella)
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What is the most common kidney stone?
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calcium oxalate or phosphate, from hypercalcemia
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Under what conditions do you often see uric acid kidney stone?
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hyperuricemia (gout, leukemia, myeloproliferative disorders)
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Tell me about Wilm's tumor:
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- mostly early childhood tumor
- deletion WT1 gene on ch11 - huge flank mass - WAGR: Wilm's tumor, aniridia, genitourinary malformation, mental-motor retardation |
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Painless hematuria with RBCs in urine suggest:
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bladder cancer (transitional cell CA)
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Where else can you see transitional cell CA besides bladder?
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renal calyces, renal pelvis, ureters
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Transitional cell CA is associated with: (4)
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- phenacetin (analgesic)
- smoking - aniline dyes - cyclophosphamide (hemorrhagic cystitis, used for NHL, breast & ovarian CA) |
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Fever, costovertebral angle tenderness, WBC casts, neutrophil infiltrate with abscesses in renal interstitium =
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acute pyelonephritis
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Lymphocyte infiltrate, fibrosis, eosinophilic casts in renal tubules =
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chronic pyelonephritis
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What is it called when there is acute general infarction of the cortices of both kidneys? What can cause this?
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Diffuse cortical necrosis: vasospasm, DIC, obstetric catastrophes, septic shock
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Renal ischemia, crush injury, toxins, can all lead to ___ ___ ___ which is the most common cause of acute renal failure.
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acute tubular necrosis
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Renal papillary necrosis is associated with: (3)
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1) diabetes mellitus
2) chronic phenacetin use 3) acute pyelonephritis |
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What is the definition of acute renal failure?
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decline in renal function w/increase in BUN and creatinine over a period of several days
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What can cause post-renal acute renal failure?
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bilateral outflow obstruction: stones, BPH, neoplasia
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What are causes of intrinsic acute renal failure?
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acute tubular necrosis, ischemia, toxins
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What are causes of pre-renal acute renal failure?
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hypotension --> decreased RBF
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A patient comes in with urine osmolality > 500. Which type of acute renal failure does he have?
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pre-renal acute renal failure
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What are consequences of renal failure?
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1) anemia
2) hyperkalemia 3) metabolic acidosis 4) renal osteodystrophy 5) uremic encephalopathy 6) HTN 7) chronic pyelonephritis |
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Too much serum Na -->
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irritability, delirium, coma
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Not enough serum Na -->
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disorientation, stupor, coma
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Too much serum Cl, secondary to:
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secondary to metabolic acidosis (with normal anion gap)
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Not enough serum Cl, secondary to:
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secondary to metabolic alkalosis
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Too much serum K -->
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peaked T waves, arrhythmias
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Not enough serum K -->
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U waves, flattened T waves, arrhythmias, paralysis
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Not enough calcium -->
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tetany, neuromuscular irritability
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Too much calcium -->
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ab pain, delirium, renal stones
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Not enough magnesium -->
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neuromuscular irritability, arrhythmias
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Too much magnesium -->
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delirium, dec. DTRs, cardiopulmonary arrest
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Not enough phosphate -->
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bone loss
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Too much phosphate -->
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metastatic calcification, renal stones
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