NEPHROLOGY STUDY GUIDE 2025/2026 QUESTIONS AND
SOLUTIONS GRADED A+ TIP
✔✔Glomerular Filtration Rate (GFR) - ✔✔The measure of the rate at which fluid is
filtered through the glomerular capsule.
-This calculation needs to be adjusted from things like age, gender, serum creatinine
and race.
Normal: *>90ml/min*
✔✔Renal Plasma Threshold - ✔✔The plasma concentration of a substance above
which results in the substance spilling into the urine.
-Typically this is in reference to glucose levels.
Normally, glucose is 100% reabsorbed in the proximal convoluted tubule, so you don't
see it in the urine.
-However, if the blood glucose levels are too high, the transporters responsible for
reabsorbing glucose become overwhelmed and glucose escapes reabsorption... and
stays in the filtrate. That's when you start seeing it in the pee.
✔✔Urinalysis (UA) - ✔✔A lab test
It involves 3 steps:
1. Gross Evaluation: looking at color and turbidity (is it clear or cloudy?)
2. Dipstick Analysis: Looking for blood, leukocyte esterase, nitrite, protein, pH, specific
gravity and glucose.
3. Microscopic Analysis: Looking for crystals, microbes, cells, casts and lipids
✔✔Hematuria - ✔✔The presence of RBC's in the urine.
-Transient RBC's in the urine can be totally normal.
-In an otherwise healthy young patient...*persistent hematuria should ALWAYS warrant
consultation with urology!* (it's kidney/bladder cancer until proven otherwise).
✔✔hematuria - ✔✔*persistent _____should ALWAYS warrant consultation with
urology!*
✔✔Pyuria - ✔✔The presence of WBC's in the urine.
-Neutrophils are typically associated with an *infection*.
-Eosinophils are often associated with allergic interstitial nephritis (often caused by a
drug reaction).
,✔✔Casts - ✔✔Cylindrical structures formed in the tubular lumen.
There are a lot of different kinds.. but the takeaway message is this:
*Hyaline casts are the only cast that can be a normal finding!*
-All other types indicate that there's a pathology.
✔✔Hyaline - ✔✔casts are the only cast that can be a normal finding!
✔✔Lipiduria - ✔✔*This is always pathologic!* A healthy kidney would not filter this large
of a molecule.
✔✔Proteinuria - ✔✔T*This term is often interchangable with Albuminuria*... because
we're usually just looking at Albumin.
*The presence of _____ in the urine (along with a kidney pathology) is a sign that that
pathology is going to be more severe than if there wasn't protein in the urine.*
-This is an important marker.
1. If we see this for greater than 3 months... that patient now has Chronic Kidney
Disease (even if everything else is normal).
2. Significant predictive marker for increased cardiovascular risk
3. Allows us to monitor disease progression/efficacy of therapy
4. Evidence suggests if we can reduce this, it leads to better outcomes.
✔✔proteinuria - ✔✔1. If we see this for greater than 3 months... that patient now has
Chronic Kidney Disease (even if everything else is normal).
✔✔Proteinuria (causes) - ✔✔This can be caused due to several different things:
1. Glomerular: There's increased glomerular permeability... letting large proteins (like
albumin) through.
2. Tubular: There's incomplete tubular reabsorption of normally-filtered low molecular
weight proteins (such as polyclonal Ig light chains).
3. Overproduction: There's increased production of low molecular weight proteins (like
monoclonal Ig light chains seen in Multiple Myeloma).
4. Post Renal: Inflammation of the urinary tract (from infection or a stone) causes
cellular damage and puts protein in the urine... downstream of the kidneys.
✔✔Proteinuria (testing) - ✔✔*We screen all patients who are at risk for CKD*! (diabetes,
HTN, obesity, autoimmune dx, family history).
1. *Albumin-to-Creatinine Ratio (ACR)*: this is the preferred test used to SCREEN for
proteinuria in adults.
Normal: *<30mg/g*
,2. Protein-to-Creatinine Ratio (PCR): this is the test we want to use to MONITOR known
proteinuria states (so we did an ACR screen and found that they have protein... from
now on we do this test to keep an eye on it!)
Normal: *<150 mg/d*
3. Dipstick: not super sensitive..
Normal: Negative to Trace
✔✔*Albumin-to-Creatinine Ratio (ACR)* - ✔✔: this is the preferred test used to
SCREEN for proteinuria in adults.
✔✔Protein-to-Creatinine Ratio (PCR): - ✔✔this is the test we want to use to MONITOR
known proteinuria states (so we did an ACR screen and found that they have protein...
from now on we do this test to keep an eye on it!)
Normal: *<150 mg/d*
✔✔Cystitis - ✔✔Inflammation of the bladder. -This is basically a UTI that has moved up
from the urethra and into the bladder.
We need to differentiate between complicated and uncomplicated cases (treatment is
different).
-It's becoming more and more common to see fluoroquinolone-resistant bacteria
causing these infections!
Pt presents with *dysuria, urinary frequency and urgency, suprapubic pain and
occasionally hematuria*.
✔✔Uncomplicated Cystitis (diagnosis) - ✔✔Defined as a non-recurrent, acute bladder
infection without conditions that would increase the risk of treatment failure (diabetes,
pregnancy, CKD, catheter, immunosuppression, severe disease, abx-resistant
pathogens)
1. HISTORY
2. UA: positive for leukocyte esterase, *nitrite*, bacteria, WBC's and/or hematuria.
3. Urine culture
Usually don't do imaging.
Typically caused by *E.coli*: 90% of UTI's are caused by this. More and more are
becoming fluoroquinolone-resistant).
✔✔Uncomplicated Cystitis (treatment) - ✔✔FIRST LINE: Nitrofurantoin (Macrobid) or
Fosfomycin!
*DON'T USE FLUOROQUINOLONES*
, ✔✔Complicated Cystitis (diagnosis) - ✔✔Defined as a bladder infection *along with
conditions that would increase the risk of treatment failure* (diabetes, pregnancy, CKD,
catheter, immunosuppression, severe or recurrent disease, abx-resistant pathogens)
1. HISTORY
2. UA: positive for leukocyte esterase, *nitrite*, bacteria, WBC's and/or hematuria.
3. Urine culture
4. Can do CT or renal US if you suspect pyelonephritis
Can be caused by many different kinds of bacteria. *They are more likely to be resistant
to many antibiotics!*.
✔✔Complicated Cystitis (treatment) - ✔✔Treatment depends... but general
considerations are:
1. Culture the bacteria and check for antibiotic sensitivities.
2. You can use Fluoroquinolones to treat this type of bladder infection.
✔✔Asymptomatic Bacteruria - ✔✔Significant bacteria (CFU >100,000) in the urine *with
no symptoms*.
This is pretty common in elderly patients.
*In general, we DON'T treat this!*
-The exception is pregnant women.
✔✔ESBL (Extended-Spectrum Beta-Lactamase producer) - ✔✔Bacteria that *produce
beta-lactamases*.
-This means that beta-lactam antibiotics (penicillins, cephalosporins) no longer work on
these bacteria.
We're also seeing more and more cases of these bacteria having fluoroquinolone
resistance as well.
✔✔Pyelonephritis - ✔✔An *infection of the kidney* and renal pelvis (so cystitis that has
ascended up into your kidneys.... a complicated UTI!).
Pt presents with *cystitis symptoms and FEVER*, as well as *CVA tenderness*,
nausea/vomiting, and sepsis/multi-organ dysfunction in severe cases.
We worry about this more than cystitis because it has it's own list of complications,
including:
-Sepsis -> shock
-Emphysematous pyelonephritis (microbes produce gas within the kidney).
-Renal abscess
SOLUTIONS GRADED A+ TIP
✔✔Glomerular Filtration Rate (GFR) - ✔✔The measure of the rate at which fluid is
filtered through the glomerular capsule.
-This calculation needs to be adjusted from things like age, gender, serum creatinine
and race.
Normal: *>90ml/min*
✔✔Renal Plasma Threshold - ✔✔The plasma concentration of a substance above
which results in the substance spilling into the urine.
-Typically this is in reference to glucose levels.
Normally, glucose is 100% reabsorbed in the proximal convoluted tubule, so you don't
see it in the urine.
-However, if the blood glucose levels are too high, the transporters responsible for
reabsorbing glucose become overwhelmed and glucose escapes reabsorption... and
stays in the filtrate. That's when you start seeing it in the pee.
✔✔Urinalysis (UA) - ✔✔A lab test
It involves 3 steps:
1. Gross Evaluation: looking at color and turbidity (is it clear or cloudy?)
2. Dipstick Analysis: Looking for blood, leukocyte esterase, nitrite, protein, pH, specific
gravity and glucose.
3. Microscopic Analysis: Looking for crystals, microbes, cells, casts and lipids
✔✔Hematuria - ✔✔The presence of RBC's in the urine.
-Transient RBC's in the urine can be totally normal.
-In an otherwise healthy young patient...*persistent hematuria should ALWAYS warrant
consultation with urology!* (it's kidney/bladder cancer until proven otherwise).
✔✔hematuria - ✔✔*persistent _____should ALWAYS warrant consultation with
urology!*
✔✔Pyuria - ✔✔The presence of WBC's in the urine.
-Neutrophils are typically associated with an *infection*.
-Eosinophils are often associated with allergic interstitial nephritis (often caused by a
drug reaction).
,✔✔Casts - ✔✔Cylindrical structures formed in the tubular lumen.
There are a lot of different kinds.. but the takeaway message is this:
*Hyaline casts are the only cast that can be a normal finding!*
-All other types indicate that there's a pathology.
✔✔Hyaline - ✔✔casts are the only cast that can be a normal finding!
✔✔Lipiduria - ✔✔*This is always pathologic!* A healthy kidney would not filter this large
of a molecule.
✔✔Proteinuria - ✔✔T*This term is often interchangable with Albuminuria*... because
we're usually just looking at Albumin.
*The presence of _____ in the urine (along with a kidney pathology) is a sign that that
pathology is going to be more severe than if there wasn't protein in the urine.*
-This is an important marker.
1. If we see this for greater than 3 months... that patient now has Chronic Kidney
Disease (even if everything else is normal).
2. Significant predictive marker for increased cardiovascular risk
3. Allows us to monitor disease progression/efficacy of therapy
4. Evidence suggests if we can reduce this, it leads to better outcomes.
✔✔proteinuria - ✔✔1. If we see this for greater than 3 months... that patient now has
Chronic Kidney Disease (even if everything else is normal).
✔✔Proteinuria (causes) - ✔✔This can be caused due to several different things:
1. Glomerular: There's increased glomerular permeability... letting large proteins (like
albumin) through.
2. Tubular: There's incomplete tubular reabsorption of normally-filtered low molecular
weight proteins (such as polyclonal Ig light chains).
3. Overproduction: There's increased production of low molecular weight proteins (like
monoclonal Ig light chains seen in Multiple Myeloma).
4. Post Renal: Inflammation of the urinary tract (from infection or a stone) causes
cellular damage and puts protein in the urine... downstream of the kidneys.
✔✔Proteinuria (testing) - ✔✔*We screen all patients who are at risk for CKD*! (diabetes,
HTN, obesity, autoimmune dx, family history).
1. *Albumin-to-Creatinine Ratio (ACR)*: this is the preferred test used to SCREEN for
proteinuria in adults.
Normal: *<30mg/g*
,2. Protein-to-Creatinine Ratio (PCR): this is the test we want to use to MONITOR known
proteinuria states (so we did an ACR screen and found that they have protein... from
now on we do this test to keep an eye on it!)
Normal: *<150 mg/d*
3. Dipstick: not super sensitive..
Normal: Negative to Trace
✔✔*Albumin-to-Creatinine Ratio (ACR)* - ✔✔: this is the preferred test used to
SCREEN for proteinuria in adults.
✔✔Protein-to-Creatinine Ratio (PCR): - ✔✔this is the test we want to use to MONITOR
known proteinuria states (so we did an ACR screen and found that they have protein...
from now on we do this test to keep an eye on it!)
Normal: *<150 mg/d*
✔✔Cystitis - ✔✔Inflammation of the bladder. -This is basically a UTI that has moved up
from the urethra and into the bladder.
We need to differentiate between complicated and uncomplicated cases (treatment is
different).
-It's becoming more and more common to see fluoroquinolone-resistant bacteria
causing these infections!
Pt presents with *dysuria, urinary frequency and urgency, suprapubic pain and
occasionally hematuria*.
✔✔Uncomplicated Cystitis (diagnosis) - ✔✔Defined as a non-recurrent, acute bladder
infection without conditions that would increase the risk of treatment failure (diabetes,
pregnancy, CKD, catheter, immunosuppression, severe disease, abx-resistant
pathogens)
1. HISTORY
2. UA: positive for leukocyte esterase, *nitrite*, bacteria, WBC's and/or hematuria.
3. Urine culture
Usually don't do imaging.
Typically caused by *E.coli*: 90% of UTI's are caused by this. More and more are
becoming fluoroquinolone-resistant).
✔✔Uncomplicated Cystitis (treatment) - ✔✔FIRST LINE: Nitrofurantoin (Macrobid) or
Fosfomycin!
*DON'T USE FLUOROQUINOLONES*
, ✔✔Complicated Cystitis (diagnosis) - ✔✔Defined as a bladder infection *along with
conditions that would increase the risk of treatment failure* (diabetes, pregnancy, CKD,
catheter, immunosuppression, severe or recurrent disease, abx-resistant pathogens)
1. HISTORY
2. UA: positive for leukocyte esterase, *nitrite*, bacteria, WBC's and/or hematuria.
3. Urine culture
4. Can do CT or renal US if you suspect pyelonephritis
Can be caused by many different kinds of bacteria. *They are more likely to be resistant
to many antibiotics!*.
✔✔Complicated Cystitis (treatment) - ✔✔Treatment depends... but general
considerations are:
1. Culture the bacteria and check for antibiotic sensitivities.
2. You can use Fluoroquinolones to treat this type of bladder infection.
✔✔Asymptomatic Bacteruria - ✔✔Significant bacteria (CFU >100,000) in the urine *with
no symptoms*.
This is pretty common in elderly patients.
*In general, we DON'T treat this!*
-The exception is pregnant women.
✔✔ESBL (Extended-Spectrum Beta-Lactamase producer) - ✔✔Bacteria that *produce
beta-lactamases*.
-This means that beta-lactam antibiotics (penicillins, cephalosporins) no longer work on
these bacteria.
We're also seeing more and more cases of these bacteria having fluoroquinolone
resistance as well.
✔✔Pyelonephritis - ✔✔An *infection of the kidney* and renal pelvis (so cystitis that has
ascended up into your kidneys.... a complicated UTI!).
Pt presents with *cystitis symptoms and FEVER*, as well as *CVA tenderness*,
nausea/vomiting, and sepsis/multi-organ dysfunction in severe cases.
We worry about this more than cystitis because it has it's own list of complications,
including:
-Sepsis -> shock
-Emphysematous pyelonephritis (microbes produce gas within the kidney).
-Renal abscess
