Renal function Flashcards by Angela Maestre

relationship b/ blood vol. & blood pressure ( give scientific names)

Hypovolemia => hypotension (lo BP)

Hypervolemia => hypertension (Hi BP)

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Meaning of Polyuria, Oliguria, Anuria

Polyuria: urine vol. >3000ml
Oliguria: urine vol. <400ml
Anuria: urine vol. <100ml

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GFR reference range for normal peroson

80-140 mL/min

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normal reference range for creatine

80-120 umol/L

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Difference b/wCockcroft-Gault equation & MDRD equation

C-G equ: “Body weight-Age-sex”

MDRD equ: “Ethnicity-age-sex”

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kidney filtrates _L/day of plasma and reabsorb more than _% of the amount filtered

180L/day

99%

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Function of kidney (3)

regulate fluid & electrolytes
excrete metabloic wastes
endocrine function (make Vit. D)

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T/F: Each nephron produces ~100 µL of urine per day.

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In the kidney, the tubular secretion of ——– from the blood into the tubular fluid helps the blood to keep its pH in the normal level?

H+ and NH4+

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Most of the blood acids are coming from

CO2 bc its volatile & can easily dissociate w/ water

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renal threshold

The plasma concentration above which the substance appears in the urine

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What is desmopressin

ADH analougue (ADH drug)

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What is the reference range for GFR?

80 – 140 mL/min

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Plasma creatinine [inc. OR dec.] as GFR decrease

increas

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T/F: plasma creatinine is influenced by muscle mass, age and ethnicity.

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What are the front line tests in assessing GFR?

Plasma/serum urea and creatinine

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What was a major con for measuring the actual GFR (aka creatinine clearance test)? so what’s the alternative test?

24hr urine collection

eGFR (estimated GFR)

Equation for GFR when doing the creatinine clearance test

[plasma creatinine] x 24 x 60 min

Cockcroft–Gault equation “Body weight – Age - Sex” to give Creatinineclearance(mL/min)

[140 - age(yrs)] x weight(kg)

815 (OR 0.85 fem.) x serum creatinine (mmol)

What circumstances would force the use of GFR test (e.g. 24hr creatinine test) instead of eGFR?

malnutrition or obesity
disease in skeletal muscle
extreme body size & age

what happens in kidney damage? (GFR, urine vol. [waste products])

Lo GFR
Lo urine vol
High [waste product]

name & describe the 3 ways acute renal failure can occur

prerenal: interupted blood flow to kidneys = dec. blood vol.
Intrarenal: damage in the kidneys (e.g inflammation) => tubular necrosis
Postrenal: obstruction of urine flow (e.g. prostate gland)

What is the BUN test?

BUN = blood urea nitrogen

- measures amount of N in blood (usually from urea) => helps indicate renal function

Define uremia & cause

inc. urine in blood

bc low blood flow = inc. urea in blood = urine in blood

define hematuria

inc. blood in urine

the BUN:Cr ratio expected in prerenal, renal & postrenal uremia

``` Pre= BUN:Cr >20 Renal= BUN:Cr <15 Post= BUN:Cr >15 ```

What's the difference b/w pre-renal disorders (aka a systemic problem) & renal disorders (aka kidney problem) referring to BUN:Cr ratio

- Pre= BUN:Cr > 20 folds | - Renal: [urea] = [N] & both at Hi [ ] means they are not excreted in urine

What does the fractional excretion of sodium (FENa) determine?

Look at tubular function & determines if drop in urine production is bc: - Pre-renal damage: Hypovolemia => FENa <1% (& hi urine osmolarity) - Renal damage: FENa > 1%

What occurs in pre-renal uremia? (condition in plasma, urine osmolarity, FANa, BUN:Cr ratio)

- inc. urea, inc. creatine, hyperkalemia, metabolic acidosis - inc. urine osmolarity (less fluid excreted = concentrated) - FENa <1% - BUN:Cr > 20

What occurs in renal uremia / intrinsic renal damage? (condition in GFR, plasma, urine osmolarity & vol, FANa)

- glomerulinephritis - GFR decreases - inc. urea, inc. creatine, hyperkalemia, metabolic acidosis - Urine = plasma osmolarity. - polyuric urine - FENa >1%

What occurs in post-renal uremia? (condition in plasma, urine osmolarity, FANa, BUN:Cr ratio)

- gall stones, enlarged prostate | - BUN:Cr >15

what is renal canaliculi & the main types & how each detected

kidney stones / Nephrolithiasis - calcium stones detected by X-ray - uric acid stones can't be detected by X-ray

Chronic renal failure aka (a) is when renal function progressively deteriorates resulting in (b). And treatment is by _ or _

a. ESRD (End stage renal disease) b. Fatal uremia c. Dialysis or transplant

What test is used to assess tubular function and transplant patients?

Beta2-microglobulin

Symptoms of chronic renal failure

- symptoms of acute renal failure: inc BUN, creatinine, hyponatremia & kalemia, acidosis - repro disturbance: infertility, reduced sperm mobility - uremic frost (white/yellow crystals), brittle hair - patient smell like urine

symptoms of nephrotic syndrome (3) & cause

- Hi plasma cholesterol & TG - Hi Alb in urine (>3.5g/day) = low Alb in blood - swelling CAUSE: glomerularnephritis

Renal tubular acidosis (RTA) is a syndrome due to either a defect in proximal tubule (a) reabsorption, or a defect in distal tubule (b) secretion, or both. Resulting in (c) blood and (d) urine.

a. bicarbonate ion b. Hydrogen ion c. acidic d. alkaline (pH>7)

what are the 3 reasons you would see protemia (protein in urine)

- glomerulus dysfunction => Hi MW proteins (e.g. Alb) filtered - dysfunction in tubular reabsorption of Low MW proteins - filtration rate > reabsorption capacity (Bence-Jones)

What is rhabdomyolysis & what can it lead to?

breakdown of muscle => release myoglobin | @ large [myoglobin] can damage the kidney bc it breaks down to a toxic compound => kidney failure

How can you tell if someone is dehydrated vs having renal failure by comparing their urea & creatinine values with reference intervals?

- dehydration: values not far from RI | - renal failure: values are far from RI