SM_194a: Urine Flashcards
Describe the components of normal urine on a urinalysis
Normal urine
- Specific gravity: 1.000-1.030
- pH: 5-8
- Protein: negative-trace
- Glucose: negative
- Ketone: negative
- Bilirubin: negative
- Blood: negative
- Nitrite: negative
- Leukocyte: negative
A 24 year old woman presents complaining of dysuria and urinary frequency. The urinalysis is obtained. Your diagnosis is _____
A 24 year old woman presents complaining of dysuria and urinary frequency. The urinalysis is obtained. Your diagnosis is urinary tract infection
A 24 year old woman presents complaining of flank pain that had a sudden severe onset. She notices her urine looks darker. She has nof ever. Your diagnosis is ______
A 24 year old woman presents complaining of flank pain that had a sudden severe onset. She notices her urine looks darker. She has nof ever. Your diagnosis is kidney stone
What are causes of leukocyturia (white cells in the urine)?
Leukocyturia
- Contamination
- Infection (vaginitis, urethritis, bladder)
- Inflammation of kidney or bladder: interstitial cystitis, pyelonephritis, interstitial nephritis (eosinophils classically associated)
What are causes of nitrites in urine?
Nitrites in urine: can be detected on dipstick
- Some bacteria convert nitrates to nitrites: may be colonization or infection (or contamination)
Dipstick detects only _____ charged proteins (predominantly ______)
Dipstick detects only negatively charged proteins (predominantly albumin)
Dipstick only detects protein ______, so amount detected is dependent on urine volume
Dipstick only detects protein concentration, so amount detected is dependent on urine volume
Proteinuria can be measured by _____, _____, or ______
Proteinuria can be measured by dipstick (concentration only), ratio (accounts for concentration by correcting for creatinine: spot collection), actually measured as amount of protein excreted in a day (24 hours of urine have to be collected which can be inconvenient)
Most common cause of hematuria is ______
Most common cause of hematuria is diabetes
Describe the definitions of microalbuminuria
If the dipstick is positive for hematuria but there are no RBCs on microscopy, ______, ______, or ______ could be occurring
If the dipstick is positive for hematuria but there are no RBCs on microscopy, rhabdomyolysis, hemolysis, and dilute urine could be occurring
(look at specific gravity to see if urine is dilute)
Hematuria can be caused by _____, _____, or _____
Hematuria can be caused by GU cause, contamination, or infection
Hematuria with red blood cell casts, proteinuria, or dysmorphic RBCs suggests a ______ cause
Hematuria with red blood cell casts, proteinuria, or dysmorphic RBCs suggests a glomerular cause
A patient has a maximum tubular reabsorption of glucose of 300 mg/dL. Their serum glucose is 375 mg/dL. _____ mg/dL of glucose will be in the urine
A patient has a maximum tubular reabsorption of glucose of 300 mg/dL. Their serum glucose is 375 mg/dL. 75 mg/dL of glucose will be in the urine
Absorbing water out of the urine will _____ glucose
Absorbing water out of the urine will concentrate glucose
Specific gravity is a measure of ______
Specific gravity is a measure of how concentrated the urine is
- 1.000: pure water
- 1.030: max concentration - equivalent to osmolality of 1,100-1,200 mOsm
- 1.010-1.012: isothenuria - equivalent ot osmolality of 280 to 300 mOsM, which is the range of normal serum osmolality
Normally ____ and ____ are not present in the urine
Normally ketones and bilirubin are not present in the urine
- Ketones: think diabetic ketoacidosis or poor po intake
- Bilirubin: check liver tests, look for liver disease
Describe the clinical presentations of renal disease
Describe GU presentations of renal disease
GU
- UTIs: common, usually symptomatic, do not cause a rise in creatinine
- Pyelonephritis (kidney infection): patients much more ill, if severe can have rise in creatinine
- Kidney stones: flank pain and hematuria, can have medically predisposing causes, use serum and urine chemistry to help diagnose, drink water
- Obstruction: many causes (tumors, stones, bladder problems, intrarenal crystals), variable presentation, diagnose with ultrasound
UTIs ____ rise in creatinine
UTIs DO NOT cause rise in creatinine
(pyelonephritis causes a rise in creatinine if severe)
Describe characteristics of acute kidney injury
Acute kidney injury
- Variable based on cause
- Elevated creatinine over short period of time (urine tests help)
- Oliguria: too little urine produced
Acute kidney injury is characterized by _____ and/or _____
Acute kidney injury is characterized by increase in serum creatinine and/or oliguria
Urinary indices help differentiate _____ and _____ acute kidney injury
Urinary indices help differentiate prerenal and intrinsic acute kidney injury
- Prerenal: responding to low volume stimulus by trying to retain Na+
- ATN: intrinsic, cannot respond to low volume
Prerenal acute kidney injury ____ to low volume stimulus, while ATN ____ to low volume stimulus
(urine sediment: hematuria, proteinuria, casts(
Prerenal acute kidney injury responds to low volume stimulus, while ATN does not respond to low volume stimulus
What are normal ranges for urine sodium, potassium, and chloride?
Normal ranges
- Urine sodium: 40-220 mEq/L
- Urine potassium: 25-125 mEq/L
- Urine chloride: 80-250 mEq/L
(depends on intake and clinical status)
In prerenal (oliguric) acute kidney injury, urine sodium will be _____ while urine osmolality will be ____ high
In prerenal (oliguric) acute kidney injury, urine sodium will be low while urine osmolality will be high (because holding onto water)
- Kidney olds onto Na+ for volume (but concentrated urine to get rid of waste)
- High urine osmolality
A patient has serum potassium of 2.7 mEq/L (low) and urine potassium of > 40 mEq/L (high). The cause of the low serum potassium is ______
A patient has serum potassium of 2.7 mEq/L (low) and urine potassium of > 40 mEq/L (high). The cause of the low serum potassium is the kidney
(low serum K+ and high urine K+ is appropriate kidney response)
Interpret urine potassium with regard to _____
Interpret urine potassium with regard to serum potassium
- High serum potassium - expect a high urine potassium (> 40 mEq/L)
- Low serum potassium - expect a low urine potassium (< 20 mEq/L)
Urine chloride is useful for _____ and _____
Urine chloride is useful for non-gap metabolic acidosis and metabolic alkalosis
Describe the urine anion gap
Urine anion gap: urine K+ + urine Na+ < urine Cl- because during acidosis urine K+ + urine Na+ + urine NH4+ = urine Cl-
(urine NH4+ cannot be routinely measured)
Describe causes of non-gap metabolic acidosis
Non-gap metabolic acidosis
- Diarrhea
- Ureteral diversions
- RTA
- Hypocapnia
- Acetazolamide, amphotericin B
- Mineralocorticoid deficiency
______ and ______ are the two most important causes of non-gap metabolic acidosis
Diarrhea and RTA (renal tubular acidosis) are the two most important causes of non-gap metabolic acidosis
- If ammonium present, then diarrhea
- If no ammonium present, then RTA
Describe the causes of saline responsive (U Cl- < 10) metabolic alkalosis
Causes of saline responsive (U Cl- < 10) metabolic alkalosis
- GI loss: upper (vomiting, NG suction), low (diarrhea with Cl-, adenoma)
- Post-hypercapnia
- Diuretics
Describe causes of saline resistant (U Cl- > 20) metabolic alkalosis
Causes of saline resistant (U Cl- > 20) metabolic alkalosis
- Akali ingestion
- Adrenal excess: hyperaldosteronism, Cushing’s disease, medications (steroids)
- Bartter’s syndrome
- Gitelman’s syndrome
- Liddle’s syndrome
- Licorice
- Refeeding aklalosis
Metabolic alkalosis that responds to saline means urine chloride is ____
Metabolic alkalosis that responds to saline means urine chloride is low (U Cl- < 10)
Metabolic alkalosis that is resistant to saline means urine chloride is _____
Metabolic alkalosis that is resistant to saline means urine chloride is high (U Cl- > 20)
What are the components of assessing urine?
Components of assessing urine
- Gross evaluation of the urine (color - blood, turbid, foamy - protein)
- Urinalysis
- Urine microscopy
Describe the components of normal urine on microscopy
Normal urine components on microscopy
- RBCs: 0-2/HPF
- WBCs: 0-2/HPF
- RBC casts: 0/HPF
- WBC casts: 0/HPF
- Hyalin: 0-5/HPF
- Pigmented: 0-1/HPF
_____ casts occur in normal urine
Hyalin casts occur in normal urine
(ghost casts, if there are a lot in low flow condition can be due to dehydration or pre-renal AKI)
In ischemic AKI, cells become _____
In ischemic AKI, cells become shorter and flatter and lose microvilli
Pigmented casts occur in _____ and _____
Pigmented casts occur in ATN and rhabdomyolysis
Categories of acute kidney injury include _____, _____, and _____
Categories of acute kidney injury include intrinsic, pre-renal, and post-renal
Describe causes of intrinsic acute renal failure
Intrinsic acute renal failure
- Glomerular
- Tubular (most common): ischemic, toxic
- Interstitial
_____ might have white cell casts
Tubular interstitial diseases might have white cell casts
This is a _____ cast
This is a white cell cast
This is a ____ cast
This is a RBC cast (nephritic sediment)
(pathognomonic for glomerular disease)
Nephritic subset of glomerular acute renal failure can be _____, _____, or _____
Nephritic subset of glomerular acute renal failure can be immune complex mediated, anti-GBM disease, or pauci-immune
Describe the clinical presentations of renal disease
A patient with diabetes and microalbuminuria should be treated with _____ to _____
A patient with diabetes and microalbuminuria should be treated with ACE inhibitor to prevent progression of kidney disease
