Kidney Flashcards
role of kidney
1) Maintenance & regulation of fluid balance
2) Acid / Base & electrolyte balance:
-Sodium
-Potassium
-Bicarbonate
-Calcium
-Phosphate
-magnesium
3) excretion of wastes*: essential -> dialysis if not
-Urea
-Creatinine
-Nitrogenous waste
-Hydrogen ions
4) conservation:
-glucose- we dont want to filter this -> if people have too high glucose -> leaks through basement membrane and we pee glucose
-amino acids
-proteins
5)Production
- erythropoietin (EPO)
- 1,25 dihydroxyvitamin D (calcitriol)- know this
renal panel
-BUN
-creatinine
BMP
-Sodium- fluid volume, nerve conduction, neuromuscular function
-Potassium- acid-base balance, neuromuscular function, cardiac muscle contraction + conduction
-CO2 (HCO3-) - buffer
-Chloride- O2/CO2 exchange in RBC
-Creatinine- breakdown of product in muscle
-BUN- N2 in blood in form of urea
-Glucose- energy
creatinine description+ where is it produced
Description:
- waste product of MUSCLES in normal metabolism
-Produced in skeletal muscle, kidney, pancreas
-breakdown process of creatinine phosphate occurs at relatively constant rate and transported through bloodstream to kidneys
-kidneys filter out most of creatinine and dispose of it in urine
-Clearance from the kidneys = GFR
Creatinine: when is it high vs low
HIGH creatinine levels: kidneys are not getting proper flow or filtration issue
- kidney disease
- dehydration
- muscle breakdown
LOW creatinine:
- malnutrition
- low muscle mass
BUN description; when it is high vs low
BUN: urea found in blood
- urea = waste product of PROTEIN breakdown
- produced/converted in the liver: Amino acids -> Ammonia -> Urea
High:
- kidney disease
- heart failure
- dehydration
- gi bleeds
Low:
- liver failure
- malnutrition
Factors affecting BUN
-hydration
- protein intake
- BLOOD IN GI tract* -> absorbing the blood -> causes rise in BUN
- liver failure
- malnutrition
calcium abnormal results can mean
-kidney/liver problems
-bone disease
-thyroid disease
-cancer
-malnutrition
glucose abnormal results
High:
- diabetes/prediabetes
Low:
- hypoglycemia
- chronic damage to basement membrane -> damaging nephron
renal failure sx
-Malaise
-Headache
-Visual disturbances
-Nausea/ Vomiting
-dysuria
-wasting
renal failure signs
-Flank tenderness
-rash- nitrogen waste may deposit into skin -> irritation
-Volume of urine reduction <500 cc
-Anuria <100 cc (no urine)
-Hematuria (blood)
- Casts (crystals)
- Proteinuria (signs of basement membrane leaking), - Pyuria (pus)
-Hypertension- if BP is not affected by meds or lifestyle -> consider renal artery stenosis -
- renal artery stenosis - activates angiotensin-aldosterone system to increase BP when they don’t have enough blood flow
-Change in urine color or odor
-Lab changes
-AV knicking- redness shows longstanding HTN and diabetes
-abdominal bruit: renal artery stenosis, AAA
-peripheral neuropathy: secondary complication
causes of chronic renal failure
- uncontrolled diabetes
- HTN **
Prerenal azotemia causes and definition
-Prerenal (MC cause): reduced blood flow to the kidneys
causes:
- low BP/hemorrhage
- CHF: reduced cardiac output
- renal artery stenosis
- dehydration
Renal azotemia causes and definition
Renal: Kidney is dysfunctional
Causes:
-Disease of vessels, glomerulus, tubules, mesangium
-Autoimmune (lupus)
- infectious (glomerular nephritis)
- medication damage
Post-renal azotemia causes and definition
Post renal: obstruction of urine flow
causes:
- Anatomic obstruction: narrow ureters or AAA
-Ureter, bladder, or urethra stone
- tumor/neoplasm
- inflammatory lesion
-Congenital anomaly
azotemia: definition + three types
Definition: “nitrogen in the blood”
- high levels of nitrogen-containing compounds in the blood (urea, creatinine, waste products)
Three types:
- Prerenal: MC* -> reduced flow to the kidneys
- Renal -> kidney tissue itself is damaged
- Post renal -> obstruction of urine flow
BMP, SMA 7, chem 7
-Sodium
-Potassium
-Chloride
-Bicarbonate
-Bun
-Creatinine
-glucose
erythropoietin
-effect on CBC
-kidney stops telling you to make EPO -> less RBC formation in marrow
-less O2 delivery
other lab tests for kidney function
-Acid base with ABG
-Plasma calcium, albumin, phosphate, parathyroid hormone, Vitamin D panel
-Urinalysis
“A CUPPA tea - makes you wanna pee”
A -ABG; for acid/base
C - calcium
U - urine analysis
P - parathyroid hormone
P - phosphate
A - albumin
GFR and Creatinine Clearance (CrCl)
Creatinine Clearance:
-measures how well the kidneys filter waste products from blood
- CrCl: mL of blood that kidneys can clear of creatinine in 1 minute
-LOW CrCl = waste retention
eGFR:
-Estimates how much blood passes through the glomeruli in 1 minute
-Estimated from Creatinine clearance, age, sex and ethnicity
- high serum creatinine = low GFR (inverse relationship)
Method of measurement of Creatinine Clearance
24 hr urine collection for accuracy: measures creatinine cleared from body over 24 h
- urine creatinine
- serum creatinine
- urine volume
- collection time in minutes
Cockcroft-Gault Creatinine clearance formula:
- useful for DRUG CALCULATION use
- ex: 1 kidney = lower creatinine clearance -> increases risk of rhadomyolysis
Crockcroft-Gault formula for estimating creatinine clearance
Example Patient details:
Gender: Male
Age: 60 years
Weight: 70 kg
Serum creatinine: 1.2 mg/dL
CrCl = ((140 - AGE) x weight)/(72 x SERUM CREATININE)
Example Patient details:
Gender: Male
Age: 60 years
Weight: 70 kg
Serum creatinine: 1.2 mg/dL
CrCl = ((140− 60) × 70)/ (72 × 1.2)
CrCl= 64.81 mL/min
if female: multiply the CrCl value by 0.85!!!!!!
example:
64.81 x 0.85 = 55.09 mL/min
stage of chronic kidney disease based on GFR
-stage 1- kidney damage with normal kidney function - GFR >= 90
-stage 2- kidney damage with mild loss of kidney function- GFR 89-60
-stage 3a- mild to moderate loss of kidney function- GFR 59-45
-stage 3b- moderate to severe loss of kidney function- GFR 44-30
-stage 4- severe loss of kidney function- GFR 29-15
-stage 5- kidney failure- GFR <15
-aggressively treat underlying issue once you see any signs
-potassium rise and no urine -> consider dialysis
dehydration definition + categories of loss
Dehydration: volume depletion results from loss of Na+ and WATER
-dehydration causes pre-renal azotemia
categories:
- GI loss
- renal loss
- skin loss
- third space sequesteration
Dehydration: skin + third space sequesteration causes
Skin losses:
- sweat
- burns
- dermatological conditions
Third-space sequestration: lose fluid into extravascular space/edema
- intestinal obstruction
- crush injury
- fracture
- acute pancreatitis -> a lot of edema
dehydration: GI and Renal loss causes
Gastrointestinal losses:
-vomiting
- diarrhea
- bleeding
- external drainage
Renal losses:
- diuretics
- osmotic diuresis
- salt-wasting nephropathies (nephrotic syndrome)
- hypoaldosteronism
symptoms + labs in dehydration pts
-General: thirst, dry mouth
-Skin: decreased turgor, dry
-Cardiac: hypotension, tachycardia
Labs:
-Low urine output: ADH holds onto water
-elevations in the BUN and the BUN/serum creatinine ratio, frequently to greater than 20:1
-Low Na+ excretion in urine
BUN: creatinine ratio general descritpion
-blood urea nitrogen : creatinine (20:1) = normal = 12-20 (optimum 15)
-BUN is more susceptible to non-renal factors: liver function, diet/protein intake, + kidney function
-creatinine: more stable, less affected by diet
increased BUN/normal creatinine
-PRE-RENAL increased BUN/creat ratio
-pre-renal uremia
- high protein intake
- after GI bleeding** (increases BUN)
increased BUN/increased creat
-POST-renal increased ratio BUN/creat ratio
-both BUN and creat are elevated
-post renal obstruction
- pre-renal uremia with renal disease
decreased BUN/normal creat
-RENAL decreased BUN/creat ratio
-acute tubular necrosis
- low protein intake/ starvation
- severe liver disease
Reasons to misinterpret BUN/Creatinine ratio
1) BUN levels are influenced by diet, steroid therapy, GI BLEEDING
1a) UPPER GI BLEED PTs
- decrease in ECF volume -> further increases BUN due to proximal tubule increased reabsorption
- rate of urea production increases due to catabolism of blood proteins during bleed
2) creatinine levels are influenced by MUSCLE MASS and GFR -> low muscles = low creatinine and would make the ratio ELEVATED
urine protein test methods and normal values
Test methods:
-Urine dipstick test
-24 hr urine- spun down, more accurate -> creatinine filtration, sodium losses, assesses protein spillage
Values of urine protein:
-Normal: 150mg/ day in 24 hrs
- over 1 gram/ day abnormal
- >3.5 g/day = NEPHROTIC SYNDROME
nephrotic syndrome
- ->3.5 gram per day
Sx:
-Hypoalbuminemia- peed it out
-Edema- third space edema
-hyperlipidemia
“low proteiin in the blood becuase you pee it out, which makes you high in lipids in blood… and third space sequestering causes edema bc its a salt wasting nephrotic syndrome”
nephritis causes and sx
definition: inflammation of renal tissue
causes:
-HTN
-infectious issues
sx:
-Mild edema
-Mild proteinemia
-Hematuria
- red blood cell casts - clumped RBCs
microalbuminuria causes
-diabetic nephropathy
-HTN renal damage
Urine Electrophoresis
Lab technique to assess types of proteins present in the urine
- molecular weight of spilled protein
- assess for cause of proteinuria
Glomerular:
- Albuminuria **
- beta globulins
Tubular:
- increased albumin
- alpha 2 doublet
Overflow:
-monoclonal immunoglobin M spike
- (MULTIPLE MYELOMA)
Nonselective:
-matches serum protein
- proteins of various sizes can pass through
sodium excretion test and ranges
-Test the resorptive function of the tubules
-Not reliable on diuretic therapy or chronic kidney disease
Uses:
- serum sodium (BMP)
- serum creatinine level
- random urine sample
Range:
-Normal: less than 1% -> we reabsorb almost all Na+
- Note: FENa is usually under 1 percent in hypovolemic patients
-hyponatremia- BBB, brain swelling -> death
-HIGH: >1% in acute tubular injury or disease
Fractional Excretion of Sodium (FENa) equation
UNa x Pcr
———— x 100%
UCr xPna
Urine Sodium x Serum Creatinine
—————————————————- x 100
Urine Creatinine x Serum Sodium
since its calculating “excretion of sodium” -> urine sodium is on the numerator
- and then everything else follows pattern of urine ___ X serum ____ /urine ____ x serum ______
equations to know
-sodium excreton
-urea excretion
-creatinine clearance
fractional urea excretion
Purpose:
- Unlike FENa, it can be used with pts on DIURETICS
- helps determine pre-renal azotemia vs renal azotemia
Values:
-FEUrea of < 35%: pre-renal azotemia
Equation:
-Fractional Excretion of Urea = ((Uur X Pcreat) / (Ucreat X Pur)) x 100%
-Uur = Urine urea
-Pcreat = Plasma creatinine
-Ucreat = Urine creatinine
-Pur = Plasma urea
EXACT SAME EQUATION STYLE AS FENa just replace urine urea with urine Na+
urinalysis: physical
Color:
- pale = diabetes insipudus
-milky = fat globules; infectioin
-reddish = blood, drugs
- green = bile pigment; jaundice
- brown-black = poisoning; bleed
-Clarity: clear vs cloudy
-Specific gravity (density)
urinalysis: chemical
-pH: acidemia; alkalemia
-Glucose: DM
-Protein: renal inflammation
-Blood: infection, HTN, period blood
-Ketones: DKA, starvation
-Bilirubin
-Urobilirubin
-Nitrite- byproduct of bacteria -> bacterial infection
-Leukocyte esterase- WBC, inflammation/infection
types of casts
WBC Cast “white inter pyel (red)
-interstitial nephritis
- Pyelonephritis
RBC Cast “i love RED it makes my skin GLOw”
- Glomerulonephritis
Renal TUBULUR Cell Cast
- Acute TUBULAR Necrosis (ATN)
Granular Cast
- Chronic renal failure
-acute tubular necrosis
- (Muddy brown = ATN)
Broad or Waxy Cast
- Chronic renal failure
Hyaline Cast “EDC”
- exercise
- diuretics
- concentrated urine
Fatty Cast “lots of protein in urine bc you are fatty -> nephrotic”
- Nephrotic syndrome
“broad, waxy, and GRAN(d) all adjectives and all are chronic renal failure
- things that are “grand” will also have ATN thats brown bc the world is so grand and brown
urinalysis: microscopic tests
Sent to lab:
-Cells- epithelial cells (not proper collection)
-Bacteria
-Crystals
-Casts
-Lipids
-contaminants
quantity of urine
Normal: 1000-1500mL a day
-polyuria- diabetes mellitus, diabetes insipidus, nervous diseases, chronic nephritis, diuretics
-oliguria (low output) - acute nephritis, heart disease, dehydration
-Anuria: uremia (nitrogenous waste in blood), acute nephritis, severe kidney failure, metal poisoning, obstruction
color of urine
-pale- diabetes insipidus, dilute
-milky- fat globules, pus in GU infections
-reddish- blood pigments, drugs, food pigments
-greenish- bile pigments, jaundice
-brown-black- poisoning, hemorrhage
transparency: urine
-clear- normal
Cloudy:
- precipitation of mucin from UTI (Not pathologic)
- crystals
-turbid- precipitation of calcium phosphate (not pathologic)
abnormal:
-milky- presence of fat globules
odor
-pleasant (sweet)- acetone- diabetes mellitus
-unpleasant- decomposition or ingestion of certain drugs or foods
-peppermint- menthol ingestion
-acid- asparagus diet
-spicy- ingestion of sandalwood oil or saffron
proteinuria what disease states
Diseases:
-nephrotic syndrome
- nephritis
- DM nephropathy (microalbuminuria)
- HTN renal damage (microalbuminuria)
specific gravity
Density of urine/density of water
- normal: 1.005-1.030
-specific gravity is proportional to volume
Low:
- dilution urine
High:
- dehydration
- volume large: DM
- proteinuria
acidity
High:
-acidosis
- diabetes mellitus
- fevers
- starvation
Alkaline
- vegetarian diet
- infection
- ingestion of alkaline compounds
urinaylsis results
-ketones can be high with keto diet
-blood also consider tumor
calcium stones
-calcium oxalate- MC *
-calcium phosphate
-can be caused by high calcium -> HYPERPARATHYROIDISM
-high oxalate can also cause increased risk for calcium stones
uric acid stones
Causes:
- low urine output
-excessive intake of proteins: red meat
- alcohol
- inflammatory bowel disease
- gout
NOT visible in plain x-ray** -> need to take US of kidney!!!!!!
-dont r/o if you dont see on x-ray!
uREA-> LEA has GI issues from her stones
“LEA GI”
-low urine output
-excessive protein intake
-alchohol
-GOUT
IBD
struvite
-associated with UTI
-can grow very rapidly forming cast in urinary tract (staghorn calculus)
-left untreated -> chronic infection and permanent kidney damage
STRUvite
-“STaghorn calculus
-UTI
-need to treate or else infection will be chronic then permanent damage
cystine stone
-Cause: inherited defect in amino acid transport
-manifests as recurrent stones in young pts
stone tx
-lithotripsy
-hydration
-drink alkaline (change environment)- cranberry juice
-antibiotics for infection
-cystine stone- specialist
-try to collect stone for identification
crystals
-precursor to stone formation
-can be found in urinalysis
-41 male
-longstanding hx of HTN and diabetes
-pruritus, lethargy, lower extremity edema
-nausea and emesis- acute process
-AV nicking and copper wire changes
-180/110 bp
-tachypnea but no tachycardic
-no fever
-2+ lower extremity edema and superficial excoriation of his skin from scratching
-moderate distress- acute
-S1,S2,S4
-longstanding hx of HTN and diabetes
-pruritus, lethargy, lower extremity edema
-nausea and emesis- acute process
-AV nicking and copper wire changes
-180/110 bp
-tachypnea but no tachycardic
-no fever
-2+ lower extremity edema and superficial excoriation of his skin from scratching
-moderate distress- acute
-S1,S2,S4
-potassium- high (vomiting, fluid in legs)
-CO2- low
-BUN- very high
-creatinine- very high
-creatinine, BUN, and K are high -> nausea and itching
-10:1 ratio
-alkaline phosphatase- high
-parathyroid hormone- very high
-Hmg- low
-Hct- low
-mean cell volume- normocytic anemia
-specific gravity- 1.010- dilute
-waxy casts- chronic renal failure
-pH 6
-urine- proteinuria
-creatinine clearance- 6.5
-stage 5 renal failure
-dialysis asap
diabetes
-microvascular damage
-anywhere
-nephropathy
-peripheral neuropathy
-eyes
A 14-year-old boy is brought to the pediatrician by his mother because he has had a fever with shaking
chills for the past day. On physical examination, he has a temperature of 39.6 C and has mild right
costovertebral angle tenderness.
chills for the past day. On physical examination, he has a temperature of 39.6 C and has mild right
costovertebral angle tenderness.
do this case
