Kidney Flashcards
role of kidney
-Maintenance & regulation of fluid balance
-Acid / Base & electrolyte balance:
-Sodium
-Potassium
-Bicarbonate
-Calcium
-Phosphate
-magnesium
-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
-excretion of wastes*: essential -> dialysis if not
-Urea
-Creatinine
-Nitrogenous waste
-Hydrogen ions
-Production of erythropoietin- know this
-Production of 1,25 dihydroxyvitamin D- know this
renal panel
-BUN
-creatinine
BMP
-BUN- N2 in blood in form of urea
-CO2 (HCO3-) - buffer
-Creatinine- breakdown of product in muscle
-Glucose- energy
-Chloride- O2/CO2 exchange in RBC
-Potassium- acid-base balance, neuromuscular function, cardiac muscle contraction + conduction
-Sodium- fluid volume, nerve conduction, neuromuscular function
creatinine
-kidneys are not getting proper flow or filtration issue if creatinine is high
-too little creatinine - malnutrition and low muscle mass
-too much- kidney disease, dehydration, muscle breakdown
BUN
-too much- kidney disease, dehydration, heart failure
-too little- liver failure, malnutrition
electrolytes
-Sodium
-Potassium
-Bicarbonate
-Calcium
-Phosphate
-magnesium
-abnormal:
-dehydration
-kidney disease
-heart failure
-liver disease
-high BP
calcium
-abnormal:
-kidney/liver problems
-bone disease
-thyroid disease
-cancer
-malnutrition
glucose
-abnormal results:
-too much- diabetes, prediabetes
-too little- hypoglycemia
-chronic damage to basement membrane -> damaging nephron
renal failure
-symptoms:
-Malaise
-Headache
-Visual disturbances
-Nausea
-Vomiting
-dysuria
-wasting
-signs:
-Flank tenderness
-rash- nitrogen waste may deposit into skin -> irritation
-Volume of urine reduction <500 cc
-Anuria <100 cc
-Hematuria, Casts, Proteinuria (signs of basement membrane leaking), Pyuria (pus)
-Hypertension- if BP is not affected by meds or lifestyle -> consider renal artery stenosis -> activates ACE to increase pressure
-Change in color or odor
-Lab changes
-AV knicking- redness shows longstanding HTN and diabetes
-abdominal brewey- renal artery stenosis, AAA
-peripheral neuropathy
causes of renal failure
-basement membrane
-vascular disturbances
-low flow state- acute
-renal artery stenosis- obstruction
-kidney stones- obstruction
-obstruction alters fluid backup and disturbs osmotic gradients -> alters GFR
-MC -> diabetes, HTN
azotemia
-nitrogen byproducts in the blood
-Prerenal (MC cause): any issue before kidneys:
-Reduced flow to kidney- low BP
-CHF, hemorrhage, renal artery stenosis, dehydration
-Renal:
-Kidney is dysfunctional
-Disease of vessels, glomerulus, tubules, mesangium
-Autoimmune (lupus), infectious (glomerular nephritis), medication damage
-postrenal:
-Anatomic obstruction (narrow ureters, AAA, tumor)
-Ureter, bladder, or urethra stone
-Congenital anomaly
-Inflammatory lesion
-neoplasm
BMP, SMA 7, chem 7
-Sodium
-Potassium
-Chloride
-Bicarbonate
-Bun
-Creatinine
-glucose
eryhtropoietin
-effect on CBC
-kidney stops telling you to make EPO -> less RBC formation in marrow
-less O2 delivery
other lab tests
-Acid base with ABG
-Plasma calcium, albumin, phosphate, parathyroid hormone, Vitamin D panel
-Urinalysis
creatinine
-chemical waste molecule that is generated from muscle metabolism
-transported through bloodstream to kidneys
-kidneys filter out most of creatinine and dispose of it in urine
-Breakdown of creatine phosphate
-Produced in skeletal muscle, kidney, pancreas
-Clearance from the kidneys = GFR
GFR and CRCL
-Milliliters of body fluid cleared by the kidneys per minute, mL/min
-Reduction represents waste retention
-Usually based on creatinine clearance
-Estimated from Creatinine, age, sex and ethnicity.
-24 hr urine collection for accuracy- Uses urine creatinine, serum creatinine, urine volume and collection time in minutes
-For drug calculation use Cockcroft-Gault Creatinine clearance formula
Crockcroft-Gault formula for estimating creatinine clearance
-used for drug calculation
-adjust dose based on this
-impaired function, 1 kidney
-lower creatinine clearance-> increase risk for rhabdo
stage of chronic kidney disease
-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
BUN
-Blood urea nitrogen
-Amino acids -> Ammonia -> Urea produced by the liver
-Can be affected by hydration, protein intake, blood in GI tract*, liver failure, malnutrition
-absorbing the blood -> causes rise in BUN
dehydration
-Volume depletion results from loss of Na and water from the following anatomic sites:
-dehydration causes pre-renal azotemia
●Gastrointestinal losses- vomiting, diarrhea, bleeding, and external drainage
●Renal losses- diuretics, osmotic diuresis, salt-wasting nephropathies (nephrotic syndrome), and hypoaldosteronism
●Skin losses- sweat, burns, and other dermatological conditions
●Third-space sequestration- intestinal obstruction, crush injury, fracture, and acute pancreatitis -> a lot of edema -> lose fluid into extravascular space
symptoms of dehydration in pt
-General?
-Skin?
-Cardiac?
-Labs?:
-Low urine output- ADH holds onto water
-elevations in the BUN and the BUN/serum creatinine ratio-> greater than 20:1
-Low Sodium Excretion in urine
BUN: creatinine ratio
-blood urea nitrogen : creatinine (20:1) = normal = 12-20 (optimum 15)
-WNL- 10-20 to 1
-creatinine is another NPN
-BUN:creatinine ratio- LOW (< 20:1) -> acute tubular necrosis, low protein intake, starvation, severe liver disease
-HIGH (> 20:1) -> pre-renal uremia, high protein intake, after GI bleeding**
-HIGH with raised creatinine -> post renal obstruction, pre-renal uremia with renal disease
increased BUN/normal creat
-pre-renal increased BUN/creat ratio
-BUN is more susceptible to non-renal factors
-pre-renal uremia, high protein intake, after GI bleeding**
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
-low dietary protein or severe liver disease
-acute tubular necrosis, low protein intake, starvation, severe liver disease
special circumstances with BUN
-Although an elevated BUN/serum creatinine may indicate hypovolemia -> subject to misinterpretation for 2 major reasons:
-1) the BUN is affected by the rate of urea production; a high ratio may be due solely to increased urea production (as with steroid therapy) rather than hypovolemia, whereas a normal ratio may occur in patients with hypovolemia if urea production is reduced (eg, due to decreased protein intake);
-2) the serum creatinine is affected by muscle mass as well as GFR; a high ratio may be due to a low muscle mass (which lowers the serum creatinine concentration), increasing the BUN/serum creatinine ratio in the absence of hypovolemia.
-A special case is the increased BUN/serum creatinine ratio in pts with upper GI bleeding. In such patients, the ratio increases markedly for 2 reasons:
-ECF volume is decreased due to the blood loss, which increases proximal tubule urea reabsorption
-rate of urea production is increased due to the catabolism and absorption of blood proteins from the GI tract
urine protein
-Urine dipstick
-24 hr urine- spun down, more accurate -> creatinine filtration, sodium losses, protein spillage
-Normal 150mg per day in 24 hrs
->1 gram per day abnormal
nephrotic syndrome
- ->3.5 gram per day
-Hypoalbuminemia- peed it out
-Edema- third space edema
-hyperlipidemia
nephritis
-inflammation of renal tissue
-Htn
-can be due to infectious issues
-Mild edema
-Mild proteinemia
-Hematuria / red blood cell casts
microalbuminuria
-Dm nephropathy
-HTN renal damage
proteinuria
-Assess for cause of proteinuria
-Molecular weight of spilled protein
-Urine electrophoresis:
-Glomerular issue (basemembrane): high albuminuria & Beta globulins
-Tubular: alpha-2 doublet (dont need to know), increased albumin
-Overflow (spilling of protein): monoclonal immunoglobulin “ M spike” (multiple myeloma)** board question
-Nonselective: matches serum Protein
sodium excretion
-Test the resorptive function of the tubules
-Uses serum sodium (BMP) and Creatinine level with a random urine sample
-Normal is less than 1% -> we reabsorb almost all Na
-hyponatremia- BBB, brain swelling -> death
->1% in acute tubular injury or disease
-Not reliable on diuretic therapy or chronic kidney disease
-the FENa is usually under 1 percent in hypovolemic patients and above 1 percent when the oliguria is due to acute tubule necrosis
fractional excretion of sodium (FENa)
equations to know
-sodium excreton
-urea excretion
-creatinine clearance
fractional urea excretion
-A fractional excretion of urea (FEUrea) of < 35% is suggestive of pre-renal azotemia. Unlike when measuring of the fractional excretion of sodium, (FENa), it can be used even when patients are taking diuretics
-Fractional Excretion of Urea = Uur X Pcreat / Ucreat X Pur · 100%
-Where:
-Uur = Urine urea
-Pcreat = Plasma creatinine
-Ucreat = Urine creatinine
-Pur = Plasma urea
urinalysis: physical
-Color
-Clarity
-Specific gravity (density)
urinalysis: chemical
-pH
-Glucose
-Protein
-Blood
-Ketones
-Bilirubin
-Urobilirubin
-Nitrite- byproduct of bacteria
-Leukocyte esterase- WBC*
urinalysis: microscopic
-sent to lab
-Cells- epithelial cells (not proper collection)
-Bacteria
-Crystals
-Casts
-Lipids
-contaminants
quantity of urine
-1000-1500mL a day
-polyuria- diabetes mellitus, diabetes insipidus, nervous diseases, chronic nephritis, diuretics
-oliguria- acute nephritis, heart disease, fever, eclampsia, diarrhea, vomiting, inadequate fluid intake
-aruria- uremia (nitrogenous waste in blood), acute nephritis, metal poisoning, complete obstruction of urinary tract
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
-cloud on standing- precipitation of mucin from urinary tract (Not pathologic)
-turbid- precipitation of calcium phosphate (not pathologic)
abnormal:
-milky- presence of fat globules
-turbid- presence of pus due to inflammation of urinary tract
odor
-pleasant (sweet)- acetone- diabetes mellitus
-unpleasant- decomposition or ingestion of certain drugs or foods
-peppermint- menthol ingestion
-acrid- asparagus diet
-spicy- ingestion of sandalwood oil or saffron
proteinuria
-albumin- altered renal function (renal pathology or systemic disease like diabetes)
-globulin- Bence-Jones proteins* (M spike) assoc with multiple myeloma and disease of globulin metabolism -> other types of globulins may be present in acute and chronic pyelonephritis
specific gravity
-specific gravity is proportional to volume
-low (chronic)- dilution if volume is large -> otherwise nephritis
-high (Chronic)- acute nephritis concentrated if volume is small -> otherwise light colored and volume large -> diabetes mellitus
acidity
-high- acidosis, diabetes mellitus, fevers, starvation
-alkaline- vegetarian diet changes urea into ammonium carbonate, infection or ingestion of alkaline compounds
approach to pt with red brown urine flow chart
urinaylsis results
-ketones can be high with keto diet
-blood also consider tumor
urinary casts
-broad or waxy cast- chronic renal failure
-WBC cast- interstitial nephritis / pyelonephritis
-renal tubular epithelial cell cast- acute tubular necrosis (ATN)
-RBC cast- glomerulonephritis
-hyaline cast- exercise, diuretics, concentrated urine
-granular cast- chronic renal failure, muddy brown = ATN
-fatty cast- (oval fat bodies) nephrotic syndrome
where you feel pain with stone
-connect to bladder
-psoas muscle
-exiting the kidney
calcium stones
-composed of calcium compounds
-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
-formed due to low urine output
-excessive intake of proteins especially red meat, alcohol, inflammatory bowel disease, gout
-not visible in plain x-ray** -> US of kidney
-dont r/o if you dont see on x-ray!
struvite
-associated with urinary infection
-can grow very rapidly forming cast in urinary tract (staghorn calculus)
-left untreated -> chronic infection and permanent kidney damage
cystine stone
-occur due to 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
-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.
do this case
know what causes pH changes in urine
