5 functions of kidney

elimination, reabsorption, homeostasis (water and electrolyte balance), metabolic, endocrine

how much percent cardiac output goes through kidney

25%

responsible for the production, storage, and release of a hormone called renin which regulates blood pressure

Juxtaglomerular apparatus

renin released from where

kidney

main function to create a gradient in medulla of kidney

loop of Henle

what part of kidney has countercurrent multiplier system and an area of high urea concentration

loop of Henle

cutoff values for anuria, oliguria, polyuria,

anuria < 100 mL/day

oliguria <400 mL/day

polyuria >2L

definition oncotic pressure

created by ALB to prevent movement of water from one solution to another

what is hydrostatic pressure in kidney

The blood inside the glomerulus creates glomerular hydrostatic pressure which forces fluid out of the glomerulus into the glomerular capsule

definition uremia (azotemia)

excess blood of urea, CRE, and other nitrogen compounds

definition nephritis (glomerulonephritis)

kidney inflammation

purpose of furosemide

as a loop diuretics, inhibit Na reabsorb at the ascending loop -> water loss in urine

purpose of thiazide type diuretics, example?

example: hydrochlorothiazide ->distal convoluted tubule ->retention of water in the urine

purpose of carbonic anhydrase inhibitors is to

in proximal convoluted tubule -> inhibit enzyme carbonic anhydrase -> HCO3 accumulate in the urine -> decrease Na absorption

purpose osmotic diuretics and drawbacks

an example of osmotic diuretics

increase osmolarity but limited tubular permeability

example: glucose

purpose of Tamm-Horsfall glycoprotein

protects against bacterial UTI by blocking bacterial adherence to the bladder epithelium

most abundant urine protein

Tamm-Horsfall glycoprotein (THP)

healthy U24h? pH, total volume, color, specific gravity, abundant protein

slightly acidic (5-6), 500mL+, amber color, 1.024 specific gravity, THP

where is urine formation/water filtration

glomeruli

what is the high threshold (almost completely absorbed) of reabsorption? what is the low threshold (minimally absorbed)?

high threshold: glucose, aa

low: CRE (minimally reabsorbed),

what electrolyte highly permeable at the proximal tubule?

Na

approximately 90% of HCO3 reabsorbed where, remainder in where?

proximal tubule, remainder in distal tubule,

percentage of water reabsorbed through the kidney pathway?

70% proximal, 5% loop of Henle, 10% distal, remainder collecting duct

what is countercurrent multiplication mechanism in the kidney

spends energy to reabsorb water from the tubules -> high osmolarity in the inner medulla

regulation by countercurrent multiplier mechanism where?

loop of Henle

what part of the kidney that ADH has effect on

distal tubule, collecting duct

at kidney, what the primary hormones, secondary, catabolic (degrade hormones)?

primary: renin, erythropoietin, prostaglandin

secondary: PTH, PRL, GH

Catabolic: insulin, aldosterone,

renal blood flow can be measured by what substances

p-aminohippurate (PAH)

for a healthy glomerulus, proteins larger than what protein are retained?

larger than ALB

Glomerular Sieving Coefficient (GSC) formula

GSC = tubule plasma conc / ratio of freely permeable compound (CRE, inulin)

difference acute and chronic kidney failure

ARF: rapid, electrolyte, acid-base, fluid imbalance -> difficult to control, high mortality

CRF: small, shrunken kidney; diabetes is one of major causes

what stage of kidney failure for uremic syndrome

terminal, kidney unable to function normally

classic signs of uremic syndrome

fatigue, loss of appetite, nausea, vomiting, tremors, mental, shallow breathing, metabolic acidosis

primary lab findings of uremic syndrome

reduced GFR, high BUN, CRE, hyperP, hypoCa

hyperK (myocardial contraction and rhythm)

secondary symptoms of uremic syndrome

acidemia (increased respiration to clear carbon dioxide); anemia (low erythropoietin); osteomalacia (low 1,25-D), HTN

cause of glomerulonephritis

immune-mediated injury: SLE, Wegner's disease, IgA nephropathy

findings of acute nephritic syndrome (acute glomerulonephritis)

hematuria, proteinuria (<3g/day), reduced GFR, sodium and water retention, HTN, localized edema

RBC cast -> glomerulonephritis, hyaline + granular cast -> common, waxy cast -> chronic process

nephrotic syndrome lab findings

proteinuria (>3g/day; ALB>1.5g/day), hypoALB, hyperCHOL, fat particles, edema

high alpha-2 globulin and beta globulin

cause of nephrotic syndrome

glomerulonephritis, SLE, diabetic nephropathy

what main lab result for pyuria

leukocyte esterase

nitrite in urine is an indicator for

UTI

what test should be order for urine DM patients

microALB

3 nephropathies secondary to systemic disease

diabetic nephropathy, hypertensive nephropathy, vasculitides

what substances can cause renal calculi

Ca-oxalate, Ca-PO4, UA, cystine, Mg-NH4-PO4

5 enzymes in urea cycle

CPS I (carbamoyl phosphate synthetase I)
OTC: ornitnine transcarbamoylase
AAS: argininosuccinate synthetase
AL: argininosuccinate lyase
AR: arginase

T/F: urea actively reabsorbed or secreted by tubules

F

important! normal BUN/CRE

12-20

testing reagents for urea (enzyme)

monitor decrease in what absorbance

urease, glutamate dehydrogenase -> glutamate

340nm

advantages of enzyme method and chemical method for urea testing

EZ: specificity

chemical: Fearon rxn, run at 45C, faster, good for urine and serum

fearon reaction for urea method -> describe

urea + diacetyl + heat -> diazine

conversion factor from urea to urea nitrogen

28/60=0.467

where synthesize creatine

liver, kidney, pancreas,

how much free creatine convert to CRE daily

1-2%

formula CRE clearance (mL/min) or Cockgroft-gault formula

(140-age)*weight(kg)x0.85 (if female) divided by serCRE*72

eGFR formula

Cs = (Us * V*1.73) divided by A*Ps

Cs (mL plasma cleared /min; Us (urine conc of substance; V (volume flow of urine mL/min); Ps (plasma conc of substance)

important! chemical method for CRE

Jaffe-alkaline picrate -> red-orange complex

enzyme method for CRE, what pros and cons

creatininase (more specific but more expensive)

what is major product of purine catabolism

UA

UA relates to what disease

Gout

hyperuricemia -> primary and secondary causes

Primary: overproduction of purines or underexcretion of UA

Secondary: renal retention, acidemia, increased nucleic acid turnover (tumor)

what pH for UA renal stone

pH<6

what range is for hyperuricemia, for hypouricemia

serum UA > 7, serum UA <2

does UA specimen needs protein removal step, why

yes, because of protein interference, turbidity, quenching

what chemical for UA method

what product color (what absorbance)

phosphotungstic acid, PTA

PTA is reduced by UA at pH alkaline->blue color (650-700nm)

advantage of EZ method for UA testing

uricase -> more specific than phosphotungstic acid, PTA

gold standard for GFR marker

inulin

why inulin is a gold standard marker for GFR

low MW, free cross membrane, not affected by tubule (not reabsorbed, not secreted, not metabolized)

list out the endogenous markers for GFR, pros and cons

CRE: most common
urea: inadequate
CysC: better than CRE but expensive as it uses IA

ranges for The ratio of urine osmolality to serum osmolality

normal: 1-3
after fluid restriction: 3-4.7
renal tubule deficiency: below normal
polyuria from DI: 0.2-0.7

what substance to use to calculate renal plasma flow (RPF)

PAH: para-aminohippuric acid

what is the relationship between GFR and RPF? what is the normal in this number

the normal FF (filtration fraction) equals GFR/RPF

normal example: 120/600=20%

3 chemistry methods for total protein in urine

Lowry: copper -> bind with peptide in pH>7
Turbidimetry: TCA (trichloroacetate) or benzethonium chloride
Dye binding: coomassie or pyrogallol red molybdate

formula selectivity index, normal?

IgG clr / ALB clr
(P_ALB*U_IgG/U_ALB*P_IgG)

less than 0.2->high selectivity
>0.2->non-selective

important indicator of myeloma? name and what type of protein

Bence Jones Protein-> light chains

classic test for Bence Jones Protein for myeloma

heating (precipitate at 56C and redissolve as temp going to boiling point)

2 current tests for Bence Jones Protein for myeloma

electrophoresis followed by immunofixation and typing

can also be done by nephelometry

formula Fractional Excretion of Bicarbonate

FE-HCO3 = (uHCO3 x sCr) / (sHCO3 x uCr)

why we use Fractional Excretion of Bicarbonate? what range tells us what

diagnosis of renal tubular acidosis

proximal RTA: FE=10-15%; distal <10%

pink brown color of urine can be due to

Hb or myoglobin

fat particles in urine can be due to what disease

nephrotic syndrome

dipstick color indications for TP. Hb, Gluc

TP: green, yellow in absence

Hb: orange to dark green

Gluc: green to dark brown

dipstick color indications for nitrite, WBC, pH

nitrite: pink

WBC: purple

pH: orange to blue

microscopic and possible conclusion disease for RBC, polymorphonuclear leukocyte with or without cast

RBC->hematuria, glomerular disease

with: upper UTInflammation, no cast: lower

testing procedure for oxalate stones

what chemical

EZ, acidify urine pH 1.8 to solubilize all salts -> thru charcoal column to remove interference

methyl-2-hydrazone

testing procedure for citrate stones

EZ, preincubation w/out citrate lyase ->remove endogenous compounds -> serum deproteinated -> pH 8

in conclusion, what are the best indicators for loss of renal function

CREclr and GFR

what are early substances for early signs of renal loss function

proteinuria, microALBuria