A 66-year-old man on hemodialysis receives darbepoetin alfa every 2 weeks for anemia of CKD. Transferrin saturation is 28% and ferritin 420 ng/mL. His hemoglobin was 10.1 g/dL 2 weeks ago and is 11.4 g/dL today. BP is controlled. Which action is most appropriate?

Reduce the darbepoetin alfa dose by at least 25%

Continue the dose and stop maintenance IV iron

Increase the dose to bring hemoglobin above 13 g/dL

Continue the dose; the target hemoglobin is 12–13 g/dL

A 70-year-old man with diabetes and CKD (eGFR 35 mL/min/1.73 m²) is scheduled for elective coronary angiography with iodinated contrast tomorrow. He takes metformin 500 mg twice daily, lisinopril, atorvastatin and furosemide 20 mg daily, and he is euvolemic. Which intervention is most appropriate to reduce his risk of contrast-associated AKI?

IV isotonic saline before and after contrast

IV isotonic sodium bicarbonate before contrast

Oral acetylcysteine 1,200 mg twice daily alone

A 71-year-old man with CKD stage 4 (eGFR 22 mL/min/1.73 m², not on dialysis) and HFrEF takes lisinopril and spironolactone. He presents with weakness after a week of vomiting and poor intake. K is 7.1 mEq/L (sample not hemolyzed), glucose 112 mg/dL, and the ECG shows peaked T waves and a widened QRS. Which treatment sequence is most appropriate?

IV calcium now, then insulin with dextrose, then remove potassium

Potassium binder now, then insulin with dextrose if K stays high

Insulin with dextrose now, then IV calcium if the ECG worsens

IV sodium bicarbonate now, then IV calcium if the QRS widens further

A 62-year-old man on hemodialysis has phosphorus 7.1 mg/dL despite dietary counseling, corrected calcium 10.1 mg/dL, intact PTH 480 pg/mL, and vascular calcification on an abdominal radiograph. He takes no phosphate binder. Which medication is most appropriate to start?

Sevelamer carbonate 800 mg with each meal

Aluminum hydroxide 600 mg with each meal, long term

Calcium acetate 1,334 mg with each meal

A 54-year-old man with alcohol use disorder has had poor food intake for weeks while drinking mostly beer. He is admitted with confusion and a serum sodium of 110 mEq/L, judged to be chronic; K is 2.9 mEq/L. He receives isotonic saline and potassium. Eighteen hours later he is passing 450 mL/hour of dilute urine, and his sodium is 120 mEq/L. Which action is most appropriate now?

Give D5W and desmopressin to bring the serum sodium back down

Continue therapy, since a 10 mEq/L rise is within the daily limit

Start tolvaptan to keep the sodium rising at a steady rate

Switch to 3% saline to finish correcting the sodium faster

A 62-year-old woman with type 2 diabetes and CKD (UACR 480 mg/g) started lisinopril 10 mg daily 2 weeks ago. Her SCr has risen from 1.20 to 1.45 mg/dL (about 21%), and K is 4.9 mEq/L. She is euvolemic, has no NSAID use, and her BP improved from 148/90 to 132/80 mm Hg. Which action is most appropriate?

Continue lisinopril; recheck labs in 2–4 weeks

Reduce lisinopril to 2.5 mg daily

Stop lisinopril because of acute kidney injury now

Switch lisinopril to losartan 50 mg daily

A 75-year-old man with BPH (prostate volume 30 mL) has taken tamsulosin 0.4 mg daily for 6 months. His obstructive symptoms improved, but he still has urgency and frequency 10 times a day. Post-void residual is 60 mL. He has mild cognitive impairment, and BP is 128/76 mm Hg. Which medication is most appropriate to add?

Oxybutynin IR 5 mg three times daily

A 63-year-old woman with CKD stage 4 (eGFR 21 mL/min/1.73 m², not on dialysis) has fatigue and a hemoglobin of 9.0 g/dL. MCV is 79 fL, ferritin 58 ng/mL, and transferrin saturation (TSAT) 13%. A recent colonoscopy was normal, and she has no active infection or bleeding. She has never received iron or an erythropoiesis-stimulating agent (ESA). Which first step for her anemia is most appropriate?

Replete iron first, then reassess hemoglobin before any ESA

Start an ESA now, and then recheck her iron studies in 3 months

Start an ESA together with oral iron to raise Hb quickly

Transfuse red cells to bring her hemoglobin above 10 g/dL

A 68-year-old man with type 2 diabetes and CKD stage 3b (eGFR 38 mL/min/1.73 m², UACR 900 mg/g) takes losartan 50 mg daily, empagliflozin 10 mg daily and furosemide 20 mg daily, and follows a low-potassium diet. An increase of losartan to 100 mg is planned, but K is 5.6 mEq/L. HCO3 is 24 mEq/L and he has no ECG changes. Which intervention is most appropriate?

Add patiromer 8.4 g daily and continue losartan

Add sodium polystyrene sulfonate 15 g daily long term

Switch losartan to lisinopril 20 mg daily

Stop losartan because of hyperkalemia

A 50-year-old man with primary membranous nephropathy has worsening edema (weight up 6 kg) despite furosemide 80 mg IV twice daily for 3 days with a 2-g sodium diet. Labs: serum albumin 1.9 g/dL, SCr 1.1 mg/dL, Na 138 mEq/L, K 4.0 mEq/L. Urine output is 900 mL/day. Which change is most appropriate to enhance diuresis?

Add metolazone 2.5 mg orally daily

Add tolvaptan 15 mg orally daily

Give albumin 25% IV alone, holding furosemide

Switch to oral furosemide 80 mg twice daily

A 67-year-old woman with CKD from hypertensive nephrosclerosis (no diabetes) has an eGFR of 26 mL/min/1.73 m² and a urine albumin-to-creatinine ratio of 640 mg/g on maximum-tolerated losartan. Dapagliflozin was started 4 weeks ago. Today her eGFR is 22 mL/min/1.73 m², a 15% fall; K is 4.6 mEq/L, she is euvolemic, and she has no symptoms. Which action is most appropriate?

Continue dapagliflozin; an early, reversible eGFR dip is expected

Stop dapagliflozin, since her eGFR is nearing the threshold of 20

Hold dapagliflozin until her eGFR returns to its baseline value

Halve the dapagliflozin dose and repeat the eGFR in 1 week

A 59-year-old woman on hemodialysis takes cinacalcet 60 mg daily for secondary hyperparathyroidism, with sevelamer as her phosphate binder. Today her PTH is 420 pg/mL, corrected calcium 7.3 mg/dL, and phosphorus 5.1 mg/dL, and she reports perioral tingling. Which action is most appropriate?

Hold cinacalcet until calcium is at least 8 mg/dL

Increase cinacalcet because PTH is above goal

Switch cinacalcet to IV etelcalcetide at dialysis

Continue cinacalcet and increase the sevelamer dose

A 56-year-old man with type 2 diabetes and hypertension takes amlodipine 10 mg daily, metformin and empagliflozin. BP is 128/78 mm Hg on repeated readings. Urine albumin-to-creatinine ratio is 150 mg/g on two samples 3 months apart, eGFR 70 mL/min/1.73 m², and K 4.3 mEq/L. Which change is most appropriate?

Add hydrochlorothiazide 12.5 mg daily

Make no change because BP is at goal

A 56-year-old woman with interstitial cystitis/bladder pain syndrome has taken pentosan polysulfate 100 mg three times daily for 6 years with good symptom control. She now reports difficulty reading and adjusting to dim light. An eye examination has not been done since she started therapy. Which recommendation is most appropriate?

Stop pentosan and arrange a retinal examination

Continue pentosan; recheck vision in 1 year

Continue pentosan and add amitriptyline at bedtime

Reduce pentosan to 100 mg daily and continue

BCPS Nephrology and Urology: CKD, Electrolytes, Bladder

1Protecting the kidney: the KDIGO layers

BPS files nephrology with its primary patient-care areas and urology with the tertiary ones; this page covers both.

KDIGO 2024, for CKD in general, and KDIGO 2022, for diabetes in CKD, describe a layered regimen built from renin-angiotensin system inhibitors, SGLT2 inhibitors and finerenone. Each layer has its own indication and its own monitoring signal, mostly potassium and creatinine. Learn which patients qualify for each layer from the guidelines themselves, and read every lab trend before you change a dose.

1.1Guidelines in motion

KDIGO published a 2026 guideline on anemia in CKD. Its 2026 acute kidney injury document is a draft, published in March 2026 for comment, and should be cited as a draft until the final version appears. Review sheets that call it a guideline are ahead of the source.

Kidney function also decides analgesic choice. Which opioids and anti-inflammatories a failing kidney tolerates is covered under pain management and palliative care, and it is worth reading straight after this page.

2Hyponatremia by volume status

Hypotonic hyponatremia: Low sodium with low serum osmolality, the form the treatment questions are about. Check tonicity first; a high glucose can lower the measured sodium without a water problem.
Hypovolemic: Sodium and water both lost, as with diuretics, vomiting or diarrhea. Restoring volume removes the stimulus that keeps antidiuretic hormone high.
Euvolemic: Water retained without edema, classically SIADH. Drug causes belong at the top of the list: thiazide diuretics, SSRIs, carbamazepine and oxcarbazepine, and desmopressin.
Hypervolemic: Total body sodium and water both up, as in heart failure, cirrhosis or nephrotic syndrome. Treatment goes through the underlying condition.
Acute vs chronic: Timing and symptoms decide how fast to correct. Chronic hyponatremia corrected too quickly risks osmotic demyelination, so the rate of rise is a monitoring target in its own right.

3Sodium, potassium and the failing kidney

Read each case for the trend before the value: a creatinine, potassium or sodium that is moving tells you more than one that is merely abnormal. Every option carries a note once you answer.

Study cases written by our editors, not BPS items. The real BCPS exam is computer-based multiple choice, answered in order with no going back.

Case 1 of 15 · 0 answered

How case rounds work

Pick an option to see the verdict and a note on every option. Keys while the round has focus: 1–5 or A–E answer, ← → move between cases. Nothing is saved or sent anywhere.

Case 01
A 66-year-old man on hemodialysis receives darbepoetin alfa every 2 weeks for anemia of CKD. Transferrin saturation is 28% and ferritin 420 ng/mL. His hemoglobin was 10.1 g/dL 2 weeks ago and is 11.4 g/dL today. BP is controlled. Which action is most appropriate?
Pick an option: the verdict and a note on every option open here.
Best answer: B.
The ESA label advises reducing the dose by at least 25% when hemoglobin rises by more than 1 g/dL in any 2-week period, and in dialysis patients reducing or interrupting when it approaches or exceeds 11 g/dL; both apply here. Targeting 12–13 g/dL or higher increased stroke, thrombosis, and death in CHOIR and TREAT. His iron indices are adequate, and stopping iron does not address the rapid hemoglobin rise caused by the ESA dose.
A
His iron indices are adequate, and stopping iron does nothing about the rapid ESA-driven hemoglobin rise.
B
Correct: a rise of more than 1 g/dL in 2 weeks with hemoglobin over 11 g/dL calls for an ESA dose cut of at least 25%.
C
Hemoglobin above 13 g/dL on an ESA increased stroke, thrombosis and death in CHOIR and TREAT.
D
A 12–13 g/dL target was abandoned after trials showed more harm, so continuing the dose toward it is unsafe.
Case 02
A 70-year-old man with diabetes and CKD (eGFR 35 mL/min/1.73 m²) is scheduled for elective coronary angiography with iodinated contrast tomorrow. He takes metformin 500 mg twice daily, lisinopril, atorvastatin and furosemide 20 mg daily, and he is euvolemic. Which intervention is most appropriate to reduce his risk of contrast-associated AKI?
Pick an option: the verdict and a note on every option open here.
Best answer: B.
Volume expansion with IV isotonic saline around the procedure is the only measure with consistent support, and the contrast volume should be minimized. Sodium bicarbonate was long promoted, but PRESERVE showed no benefit over saline, and acetylcysteine also showed no benefit in that trial. Mannitol and other diuretics given after contrast can worsen volume depletion and increase AKI risk.
A
Sodium bicarbonate showed no benefit over saline in PRESERVE, so it adds complexity without protection.
B
Correct: periprocedural IV isotonic saline, with the lowest feasible contrast volume, is the measure with consistent support.
C
Mannitol after contrast causes a diuresis that can deplete volume and raise AKI risk.
D
Acetylcysteine showed no benefit in PRESERVE, and using it alone omits the one measure that helps.
Case 03
A 71-year-old man with CKD stage 4 (eGFR 22 mL/min/1.73 m², not on dialysis) and HFrEF takes lisinopril and spironolactone. He presents with weakness after a week of vomiting and poor intake. K is 7.1 mEq/L (sample not hemolyzed), glucose 112 mg/dL, and the ECG shows peaked T waves and a widened QRS. Which treatment sequence is most appropriate?
Pick an option: the verdict and a note on every option open here.
Best answer: C.
Hyperkalemia with ECG changes is an emergency. The KDIGO Controversies Conference on potassium (Clase et al., Kidney International 2020) describes the order. First, give IV calcium to stabilize the cardiac membrane; it acts in minutes but does not lower potassium. Next, shift potassium into cells with insulin plus dextrose, monitoring glucose; a beta-agonist may be added. Then remove potassium from the body with a binder, a loop diuretic if he makes urine, or dialysis. Bicarbonate is not a reliable stand-alone shifting agent. Lisinopril and spironolactone should be held. Doses are left to the product labels.
A
Binders work over hours. With ECG changes, the heart must be protected first, and potassium shifted.
B
Insulin with dextrose lowers K in about 15–30 minutes but does not protect the heart; calcium comes first when the ECG is abnormal.
C
Correct. Calcium stabilizes the cardiac membrane within minutes; insulin with dextrose shifts K into cells; removal then lowers total body K.
D
Bicarbonate alone is an unreliable way to lower K, and delaying calcium with a widened QRS is dangerous.
Case 04
A 62-year-old man on hemodialysis has phosphorus 7.1 mg/dL despite dietary counseling, corrected calcium 10.1 mg/dL, intact PTH 480 pg/mL, and vascular calcification on an abdominal radiograph. He takes no phosphate binder. Which medication is most appropriate to start?
Pick an option: the verdict and a note on every option open here.
Best answer: D.
KDIGO 2017 suggests restricting calcium-based binders in CKD, especially with high-normal calcium and vascular calcification, so a non-calcium binder such as sevelamer taken with meals is preferred. Calcium acetate lowers phosphorus but adds a calcium load that worsens vascular calcification. Long-term aluminum causes bone disease and encephalopathy, and calcitriol raises both calcium and phosphorus, so it should not be started while phosphorus is this high.
A
Long-term aluminum binders cause bone disease and encephalopathy, so they are not used for maintenance.
B
Calcium acetate lowers phosphorus but adds a calcium load that worsens vascular calcification at high-normal calcium.
C
Calcitriol raises both calcium and phosphorus and should not be started while phosphorus is 7.1 mg/dL.
D
Correct: with high-normal calcium and vascular calcification, a non-calcium binder such as sevelamer taken with meals is preferred.
Case 05
A 60-year-old man with type 2 diabetes and CKD (eGFR 52 mL/min/1.73 m², UACR 620 mg/g) takes lisinopril 20 mg daily, metformin and atorvastatin. An attempt to increase lisinopril to 40 mg raised his K to 5.4 mEq/L, so it was returned to 20 mg; K is now 5.2 mEq/L. BP is 134/82 mm Hg. Which medication should be added to provide additional kidney protection?
Pick an option: the verdict and a note on every option open here.
Best answer: C.
An SGLT2 inhibitor slows CKD progression independently of the RAS inhibitor and also modestly lowers the risk of hyperkalemia, so it is the right addition for this patient (KDIGO 2024 first-line). Finerenone is the tempting choice for residual albuminuria, but it should not be started when K is above 5.0 mEq/L. Losartan would create dual RAS blockade, and spironolactone raises K further without proven kidney outcome benefit.
A
Adding losartan to lisinopril creates dual RAS blockade, which raises hyperkalemia and AKI risk without kidney benefit.
B
Spironolactone would push an already high potassium higher and lacks proven kidney outcome benefit.
C
Correct: an SGLT2 inhibitor slows CKD progression on top of the RAS inhibitor and modestly lowers hyperkalemia risk.
D
Finerenone is tempting for residual albuminuria, but it should not be started while potassium is above 5.0 mEq/L.
Case 06
A 54-year-old man with alcohol use disorder has had poor food intake for weeks while drinking mostly beer. He is admitted with confusion and a serum sodium of 110 mEq/L, judged to be chronic; K is 2.9 mEq/L. He receives isotonic saline and potassium. Eighteen hours later he is passing 450 mL/hour of dilute urine, and his sodium is 120 mEq/L. Which action is most appropriate now?
Pick an option: the verdict and a note on every option open here.
Best answer: A.
For chronic hyponatremia, the 2013 US expert panel recommendations (Verbalis et al., Am J Med) advise against raising sodium by more than 10–12 mEq/L in 24 hours in average-risk patients, and more than 8 mEq/L in patients at high risk of osmotic demyelination. High-risk patients include those with alcohol use disorder, malnutrition, hypokalemia or advanced liver disease. This patient is high risk, has risen 10 mEq/L in 18 hours, and has a brisk water diuresis as his ADH falls. The panel supports relowering the sodium with electrolyte-free water (D5W) and desmopressin when the limit is exceeded. Tolvaptan and 3% saline would make the overcorrection worse.
A
Correct. He is at high risk of osmotic demyelination and has already exceeded 8 mEq/L; D5W plus desmopressin relowers the sodium.
B
The 10–12 mEq/L limit applies to average-risk patients. With alcohol use, malnutrition and low K, the limit is 8, and the brisk water diuresis continues.
C
Tolvaptan causes more water loss and would speed up a correction that is already too fast.
D
Hypertonic saline would push the sodium up even faster in a patient who has already overcorrected.
Case 07
A 62-year-old woman with type 2 diabetes and CKD (UACR 480 mg/g) started lisinopril 10 mg daily 2 weeks ago. Her SCr has risen from 1.20 to 1.45 mg/dL (about 21%), and K is 4.9 mEq/L. She is euvolemic, has no NSAID use, and her BP improved from 148/90 to 132/80 mm Hg. Which action is most appropriate?
Pick an option: the verdict and a note on every option open here.
Best answer: B.
A creatinine rise of up to about 30% after starting RAAS blockade reflects reduced intraglomerular pressure—the mechanism of its kidney protection—so KDIGO advises continuing the drug and monitoring, provided potassium is acceptable. Stopping it for this expected change forfeits albuminuria reduction and renal protection. Lowering the dose undertreats albuminuria, and an ARB produces the same hemodynamic effect.
A
Cutting to 2.5 mg undertreats her albuminuria when the creatinine change is within the expected range.
B
Correct: a creatinine rise under 30% with acceptable potassium reflects lower glomerular pressure, so therapy continues with monitoring.
C
A rise of about 21% after starting an ACE inhibitor is an expected hemodynamic effect, not acute kidney injury.
D
An ARB lowers intraglomerular pressure the same way, so switching would produce the same creatinine change.
Case 08
A 75-year-old man with BPH (prostate volume 30 mL) has taken tamsulosin 0.4 mg daily for 6 months. His obstructive symptoms improved, but he still has urgency and frequency 10 times a day. Post-void residual is 60 mL. He has mild cognitive impairment, and BP is 128/76 mm Hg. Which medication is most appropriate to add?
Pick an option: the verdict and a note on every option open here.
Best answer: B.
With a low post-void residual on an α-blocker, an OAB agent can be added, and the β3-agonist mirabegron avoids anticholinergic effects, so it does not worsen cognition or retention; BP should be monitored. Oxybutynin and tolterodine are antimuscarinics that worsen cognitive impairment and are on the Beers list (oxybutynin strongly anticholinergic), so they are poor choices for him. Finasteride shrinks large prostates over months and does not treat storage symptoms, and his prostate is only 30 mL.
A
Tolterodine is an antimuscarinic that can worsen his cognitive impairment and is on the Beers list for older adults.
B
Correct: the beta-3 agonist mirabegron treats storage symptoms without anticholinergic effects, and his residual is low enough to add it.
C
Oxybutynin IR is strongly anticholinergic, among the worst picks for an older man with cognitive impairment.
D
Finasteride shrinks large prostates over months and does not treat urgency; his gland is only 30 mL.
Case 09
A 63-year-old woman with CKD stage 4 (eGFR 21 mL/min/1.73 m², not on dialysis) has fatigue and a hemoglobin of 9.0 g/dL. MCV is 79 fL, ferritin 58 ng/mL, and transferrin saturation (TSAT) 13%. A recent colonoscopy was normal, and she has no active infection or bleeding. She has never received iron or an erythropoiesis-stimulating agent (ESA). Which first step for her anemia is most appropriate?
Pick an option: the verdict and a note on every option open here.
Best answer: B.
The KDIGO 2026 Anemia in CKD guideline says to address correctable causes of anemia, such as iron deficiency, before starting an ESA. For people with non-dialysis CKD, it suggests iron when ferritin is below 100 ng/mL (with TSAT below 40%), or when ferritin is 100–300 ng/mL with TSAT below 25%. Her ferritin of 58 ng/mL and TSAT of 13% clearly qualify. Repleting iron, orally or IV, often raises hemoglobin by itself, and her response is then reassessed before an ESA is considered. An ESA started while she is iron deficient works poorly, and transfusion is not needed in a stable patient with a fixable cause.
A
Starting an ESA while iron deficient wastes the ESA: the marrow has too little iron to respond.
B
Correct. Ferritin 58 and TSAT 13% show iron deficiency; repletion may raise Hb on its own and lowers any later ESA need.
C
Iron deficiency should be corrected before an ESA is considered, not alongside it from the start.
D
She is stable at 9.0 g/dL with a treatable cause. Transfusion is not indicated and may sensitize a future transplant candidate.
Case 10
A 68-year-old man with type 2 diabetes and CKD stage 3b (eGFR 38 mL/min/1.73 m², UACR 900 mg/g) takes losartan 50 mg daily, empagliflozin 10 mg daily and furosemide 20 mg daily, and follows a low-potassium diet. An increase of losartan to 100 mg is planned, but K is 5.6 mEq/L. HCO3 is 24 mEq/L and he has no ECG changes. Which intervention is most appropriate?
Pick an option: the verdict and a note on every option open here.
Best answer: D.
KDIGO 2024 advises managing hyperkalemia with diet, diuretics, SGLT2 inhibitors and potassium binders so that RAS blockade can be maintained and titrated, and patiromer is suitable for chronic use. Sodium polystyrene sulfonate is the tempting older binder, but it is poorly tolerated, carries a risk of colonic necrosis, and is not suited to long-term daily use. Stopping losartan sacrifices kidney protection in heavy albuminuria, and switching to an ACE inhibitor has the same effect on potassium.
A
Sodium polystyrene sulfonate is poorly tolerated, carries a colonic necrosis risk, and is not suited to long-term daily use.
B
An ACE inhibitor raises potassium just as an ARB does, so switching does not solve the hyperkalemia.
C
Stopping losartan gives up kidney protection in heavy albuminuria when the potassium can be managed instead.
D
Correct: KDIGO 2024 favors controlling potassium with a chronic binder such as patiromer so RAS blockade can continue.
Case 11
A 50-year-old man with primary membranous nephropathy has worsening edema (weight up 6 kg) despite furosemide 80 mg IV twice daily for 3 days with a 2-g sodium diet. Labs: serum albumin 1.9 g/dL, SCr 1.1 mg/dL, Na 138 mEq/L, K 4.0 mEq/L. Urine output is 900 mL/day. Which change is most appropriate to enhance diuresis?
Pick an option: the verdict and a note on every option open here.
Best answer: D.
Prolonged loop diuretic use leads to compensatory sodium reabsorption in the distal tubule, and adding a thiazide-type diuretic such as metolazone blocks that site (sequential nephron blockade); electrolytes need close monitoring. Switching to oral furosemide at the same dose roughly halves the delivered drug because oral bioavailability is about 50%. Albumin without a loop diuretic does not cause diuresis, and tolvaptan treats hyponatremia rather than edema with normal sodium.
A
Tolvaptan treats hyponatremia, and his sodium is normal, so it does not address diuretic resistance.
B
Albumin without a loop diuretic produces no diuresis, and holding furosemide removes the active drug.
C
Oral furosemide at the same dose delivers roughly half the drug, which worsens an already inadequate response.
D
Correct: metolazone blocks compensatory distal sodium reabsorption, the sequential nephron blockade that overcomes loop resistance.
Case 12
A 67-year-old woman with CKD from hypertensive nephrosclerosis (no diabetes) has an eGFR of 26 mL/min/1.73 m² and a urine albumin-to-creatinine ratio of 640 mg/g on maximum-tolerated losartan. Dapagliflozin was started 4 weeks ago. Today her eGFR is 22 mL/min/1.73 m², a 15% fall; K is 4.6 mEq/L, she is euvolemic, and she has no symptoms. Which action is most appropriate?
Pick an option: the verdict and a note on every option open here.
Best answer: D.
The KDIGO 2024 CKD guideline recommends an SGLT2 inhibitor for adults with CKD and an eGFR of at least 20 mL/min/1.73 m² who have albuminuria of 200 mg/g or more or heart failure, with or without diabetes. She qualified at an eGFR of 26. An early fall in eGFR on starting the drug reflects reduced intraglomerular pressure and is expected. The guideline’s practice points say this reversible fall is generally not a reason to stop. Once an SGLT2 inhibitor is started, it is reasonable to continue it even if the eGFR falls below 20, unless it is not tolerated or kidney replacement therapy begins.
A
eGFR 20 is a threshold for starting, not stopping. Once started, an SGLT2 inhibitor can continue below 20 until dialysis or transplant.
B
Holding it gives up kidney protection for a hemodynamic dip that is expected and reversible.
C
No lower dose is used for kidney protection, and the dip is not a dose-related toxicity.
D
Correct. KDIGO 2024 says the reversible eGFR fall at initiation is generally not a reason to stop, and therapy can continue below 20.
Case 13
A 59-year-old woman on hemodialysis takes cinacalcet 60 mg daily for secondary hyperparathyroidism, with sevelamer as her phosphate binder. Today her PTH is 420 pg/mL, corrected calcium 7.3 mg/dL, and phosphorus 5.1 mg/dL, and she reports perioral tingling. Which action is most appropriate?
Pick an option: the verdict and a note on every option open here.
Best answer: C.
Cinacalcet lowers PTH and serum calcium; the label advises withholding it when calcium falls below 7.5 mg/dL or hypocalcemia is symptomatic, then restarting at a lower dose once calcium is ≥8.0 mg/dL (with calcium or vitamin D support as needed). Increasing the dose for PTH worsens dangerous hypocalcemia. Sevelamer is calcium-free and does not raise calcium, and etelcalcetide is also a calcimimetic that lowers calcium.
A
Raising cinacalcet would deepen a symptomatic hypocalcemia, whatever the PTH value.
B
Etelcalcetide is also a calcimimetic and lowers calcium the same way, so switching does not fix the problem.
C
Correct: with calcium below 7.5 mg/dL and tingling, cinacalcet is held until calcium reaches 8.0 mg/dL, then restarted lower.
D
Sevelamer contains no calcium, so a higher dose neither raises calcium nor treats her symptoms.
Case 14
A 56-year-old man with type 2 diabetes and hypertension takes amlodipine 10 mg daily, metformin and empagliflozin. BP is 128/78 mm Hg on repeated readings. Urine albumin-to-creatinine ratio is 150 mg/g on two samples 3 months apart, eGFR 70 mL/min/1.73 m², and K 4.3 mEq/L. Which change is most appropriate?
Pick an option: the verdict and a note on every option open here.
Best answer: C.
In a patient with diabetes and hypertension, a confirmed UACR of 30 mg/g or more is an indication for an ACE inhibitor or ARB titrated to the maximum tolerated dose to reduce albuminuria and CKD progression, even when BP is already at goal. Finerenone is added for residual albuminuria on top of a RAS inhibitor, not instead of one. Hydrochlorothiazide lowers BP but has no antialbuminuric effect, and making no change ignores the albuminuria, which is the reason to act.
A
Hydrochlorothiazide lowers BP, but BP is already at goal and a thiazide has no antialbuminuric effect.
B
Finerenone is added for residual albuminuria on top of an ACE inhibitor or ARB, not in place of one.
C
Correct: confirmed albuminuria with diabetes and hypertension calls for an ACE inhibitor or ARB, even with BP at goal.
D
Leaving the regimen unchanged ignores confirmed albuminuria, which is the reason to act here.
Case 15
A 56-year-old woman with interstitial cystitis/bladder pain syndrome has taken pentosan polysulfate 100 mg three times daily for 6 years with good symptom control. She now reports difficulty reading and adjusting to dim light. An eye examination has not been done since she started therapy. Which recommendation is most appropriate?
Pick an option: the verdict and a note on every option open here.
Best answer: D.
Long-term pentosan use is associated with pigmentary maculopathy, with risk rising with cumulative dose, so new visual symptoms call for stopping the drug and obtaining a retinal examination; the label now advises baseline and periodic retinal exams. Lowering the dose is the tempting compromise, but it keeps exposure going while vision loss may progress, and the damage may be irreversible. Adding amitriptyline treats bladder pain but ignores the ocular toxicity, and waiting a year delays diagnosis.
A
Waiting a year delays diagnosis of a maculopathy that may progress and become irreversible.
B
Amitriptyline may help bladder pain but does nothing about the suspected retinal toxicity.
C
A lower dose is a tempting compromise, yet it keeps cumulative exposure going while vision loss may progress.
D
Correct: new trouble reading and adapting to dim light after years of pentosan suggests maculopathy, so stop it and examine the retina.

4Before you answer a kidney or electrolyte case

Find the kidney function estimate the stem gives you, and decide whether the question needs eGFR or CrCl.
Note dialysis status; a patient on hemodialysis is a different dosing and binder problem from CKD stage 4.
List every drug on the profile that raises potassium or lowers sodium before you blame the disease.
Separate an emergency from a chronic problem, because the two have different answers for the same lab.
For urology items, read the patient’s age and full medication list before choosing a bladder or prostate drug.

5Short answers

Why does tonicity come before volume status?

Because a high glucose or an infused osmotic agent can lower the measured sodium without any excess water. Only hypotonic hyponatremia goes on to the volume-status split in the list above.

What does osmotic demyelination have to do with correction speed?

It is the brain injury that can follow when chronic hyponatremia is corrected too quickly, which is why the rate of rise is limited and the sodium is rechecked often during treatment. Learn the specific limits from the hyponatremia guidance you study with, together with its source and year.

What does urology cover in this outline?

BPS names Urology as a tertiary area without listing conditions. Benign prostatic hyperplasia and overactive bladder are the common pharmacotherapy topics, and both call for the full medication list to be checked before a drug is added.

6References

KDIGO 2024 clinical practice guideline for the evaluation and management of CKD. As of October 27, 2026.
KDIGO 2022 clinical practice guideline for diabetes management in CKD. As of October 27, 2026.

7Concepts in this domain

CrCl vs eGFR for dosing

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