Renal 1 Flashcards
(22 cards)
Functions of the kidney (8)
- Water and electrolyte balance (Na, K, Ca, P, etc.)
- Metabolic waste excretion
- Blood pressure control
- Erythropoietin
- Acid- base balance
- Excretion of drugs and hormones
- Activation of vitamin D
- Gluconeogenesis
Alkaline pH (5)
> 7.0
a. Bacteriuria
b. Renal failure
c. Presence of antibiotics, sodium bicarbonate
d. Diet high in vegetables, citrus fruits and dairy products
Acidic pH (8)
- Acidic (<7.0)
- Acidosis – Renal tubular acidosis
- Presence of certain drugs
- Out of control DM
- Starvation
- High-protein diet
- Ketones make urine acidic
Urine dipstick: blood
Extremely sensitive and so will detect clinically insignificantly amounts of hemoglobin or myoglobin
Color of urine: upper renal hematuria (4)
- Brown cola colored urine
- RBS, WBC casts
* Significant casts if RBC and WBC - > /= +2 proteinuria
- Deformed RBC
Color of urine: lower bladder disease (4)
a. Terminal hematuria
b. Passage of blood clots
c. = 2+ proteinuria
d. Normal RBC
Protein count (5)
- Trace (about 15 mg/dL)
- 1+ (about 30 mg/dL)
- 2+ (about 100 mg/dL)
- 3+ (about 300 mg/dL)
- 4+ (2,000 mg/dL or greater)
* Vast difference between amount of protein from 3 and 4
urine dipstick
measures albumin
*does not measure low molecular weight protein
Dipstick interpretation (4)
- Urinary dipstick method measures the concentration of urine protein,
- False-negative results-very dilute urine specimen.
- If the urine sample has specific gravity of ≤ to 1.015, then 1+ is considered positive
- If the urine sample has a specific gravity of ≥ to 1.015 then >/= to 2+ is positive
False positive dipstick results (8)
a. Very alkaline or concentrated specimens
b. Gross hematuria
c. Pyuria
d. Bacteriuria
e. Presence of contaminating antiseptics
f. Radiographic contrast
g. Presence of heavy mucus, blood, pus, semen or vaginal secretion
h. Trace positive proteinuria by dipstick does not imply pathologic proteinuria
Urine Dipstick: Nitrite and Leukocyte esterase (3)
- Negative nitrite result
a. Does not rule out UTI (poor sensitivity) - Positive result is likely true-positive
a. High specificity—whatever the collection method. - Leukocyte esterase
a. More sensitive (positive in disease) indicator of infection than nitrites are
b. Better when tested using a catheterized, rather than a bagged, specimen
Urine dipstick: Glucose/bilirubin (3)
- Urine should not contain glucose
- False positive can occur with ascorbic acid
- Most common reason for positive bilirubin is old or poorly sealed dipsticks.
Pigmenturia (3)
- Urine can get discolored from free hemoglobin, myoglobin, endogenous pigments (bili and prophyrins), food dyes, and certain drugs
- Foods: Rhubarb, beets, blackberries, blueberries, paprika, fava beans, and food dyes
- Drugs: Rifampin, nitrofurantoin, sulfonamides, metronidazole, phenytoin, quinine, chloroquine, levedopa, methyldopa, deforoxamine
Quantitative Urine Tests: Urine protein/creatinine ratio (3)
a. Random urine specimen
b. More accurate quantification
c. Normal ratio is < .2 mg of protein per milligram of creatinine in most children. <0.5 first few months of life
Quantitative Urine Tests: urine albumin/creatinine ratio (3)
a. Normal albumin secretion is less than 20 mg/d
b. 30-300 mg/d is abnormal and not detected by dipstick = microalbuminuria
c. Ratio of > .03 mg of albumin per milligram of albumin is abnormal
Other Lab to do with Abnormal Urianalysis (6)
- CBC with diff
- Complete Metabolic Profile
a. Creatinine better reflects renal function
i. BUN better reflects hydration level - SCP
- C3 and C4
- ANA
a. Checks for lupus nephritis - ASO (antistreptolysin titer), DNAse B test
a. ASO titers remain elevated for up to a year
Hematuria definition (5)
- 1+ or higher reaction on urine dipstick for blood
- Greater than 5 RBCs/HPE (40X) in three consecutive fresh centrifuged urine specimens over a 2-3 week period
- Dip stick is reacting to hemoglobin in urine
- Is this hematuria or hemoglobinuria
- High glucose can cause a false positive
How is hematuria discovered? (3)
- Onset of gross hematuria
- Onset of urinary or other symptoms with incidental finding of microscopic hematuria
- Inadvertent discovery of microscopic hematuria during a visit where a urinalysis is required (camp or sports physical)
Hematuria Urinalysis (2)
Check if it is this true hematuria
- Urine dipstick utilizes a peroxidase like reaction to detect hemoglobin and myoglobin
100% sensitivity
99.3% specificity - For familial hematuria, you need a urine sample from both parents
what causes false negatives with urinalysis (2)
- Formalin (urine preservative)
2. High urine concentration of ascorbic acid
what causes positive negatives with urinalysis (2)
- Peroxidase (skin Cleaner)
- Alkaline urine with pH >9
- Menses, fever, exercise
Four Categories of Hematuria
- Gross hematuria
- Microscopic hematuria with clinical symptoms
- Asymptomatic microscopic (isolated) hematuria
* Significant renal disease is very rare if there is only microscopic hematuria - Asymptomatic microscopic hematuria with proteinuria
* Most of these are isolated, asymptomatic hematurias
