Case 06: The Breathless Farmer

Commit to an answer before revealing the explanation. Use the section menu to navigate; each question and answer has its own link. Five-option evidence updates ask for the most defensible direction of change; discuss a justified adjacent response.

Session S2 · 2026-10-27 · in-session · 37 min Anchor: Chronic kidney disease — cardiorenal: heart failure with CKD and diuretics · Integrates: AKI (cardiorenal type 1), electrolytes (hypervolemic hyponatremia, loop-diuretic signature, hyperkalemia), GDMT and how CKD changes it, apixaban dosing, NSAIDs, "renalism" One-line hook: The night team saw a creatinine of 3.1 and wrote two orders. A new PA who can read the volume exam, judge a diuretic dose at two hours, and decide which heart-failure drugs keep running through a creatinine bump decides whether this man goes home or comes back.

Learning Objectives

Answers for this section: Q1 · Q2 · Q3 · Q4 · Q5 · Q6 · Q7 · Q8 · Q9 · Q10 · Q11

1. Classify a patient as congested or depleted from JVP, hepatojugular reflux, S3, edema, weight change and urine output, and state which signs are unreliable.
2. Explain cardiorenal syndrome type 1 in plain words — venous congestion, not low output, is what usually raises the creatinine in decompensated heart failure — and name the treatment (decongestion, not fluid).
3. Recognize hypervolemic hyponatremia and treat it with fluid restriction plus a loop diuretic, never isotonic saline.
4. Dose a loop diuretic in CKD (IV, above the threshold, roughly double the home oral dose), judge the response at about two hours (urine output and spot urine sodium), and climb the student-level resistance ladder: stop the NSAID, double the loop, add metolazone with BMP and magnesium at least twice daily during intensive combination treatment.
5. Apply the GDMT numbers in CKD: SGLT2 inhibitor — start at eGFR ≥20; once started, continue even below 20 until dialysis unless not tolerated (KDIGO 2024); steroidal MRA needs eGFR >30 and K⁺ <5.0; ARNI and beta-blocker continue; interpret a creatinine rise with perfusion, congestion and treatment response rather than a universal percentage cutoff; recognize and refuse "renalism."

Warm-Up (individual commit before the case)

Answers for this section: Q1 · Q2 · Q3

Part 1 — Presentation

Answers for this section: Q4 · Q5

Mr. V., 71, dairy farmer from a township north of Dubuque, arrives by ambulance at 21:40 on a Monday in late October. Chief complaint: "I can't lie down. I've been sleeping in the recliner for five nights." He has been more short of breath for two weeks, first on the walk to the milking parlor, now crossing the kitchen. His legs are "like fence posts." He has gained weight; the scale at the heart-failure clinic read 84 kg in August and he is 91 kg tonight.

History. Ischemic cardiomyopathy after an anterior MI with two stents (2019); heart failure with reduced ejection fraction, EF 30 % on an echo three months ago (dilated left ventricle, moderate mitral regurgitation, RV systolic pressure 48 mmHg). Permanent atrial fibrillation, rate-controlled, on apixaban. Type 2 diabetes for 18 years with background retinopathy. Chronic kidney disease G4 A3 attributed to diabetic kidney disease: creatinine 2.6 mg/dL and eGFR 26 mL/min/1.73 m² (CKD-EPI 2021) three months ago, urine albumin-to-creatinine ratio 880 mg/g. Metformin was stopped two years ago when his eGFR fell below 30. Hypertension. No prior hospital admission for heart failure.

Social. Milks 60 cows twice a day with his son; lifts 50-lb feed sacks. Wife manages his pill box. No alcohol, no tobacco. Eats "what the wife cooks" — ham, cheese, canned soup in winter. Fluid intake "a lot of coffee and a lot of water — the clinic told me to drink."

Review of systems. Orthopnea, three-pillow then recliner. No chest pain. No fever, cough or dysuria. Low back pain for three weeks after a fall from a hay wagon; "took something for it from the farm store." Urinating "less than usual" for a week.

Vitals. Blood pressure 118/72 mmHg, heart rate 88 and irregularly irregular, respiratory rate 24 breaths/min, SpO₂ 90 % on room air → 94 % on 2 L nasal cannula, temperature 36.8 °C, weight 91.0 kg (clinic dry weight 84 kg).

Exam. Sitting bolt upright, speaking in short sentences. JVP 12 cm H₂O at 45° with a positive hepatojugular reflux. S3 gallop; irregular rhythm; 2/6 apical holosystolic murmur. Crackles to the mid-lung fields bilaterally. Liver edge 3 cm below the costal margin, mildly tender. 3+ pitting edema to the knees, 2+ sacral edema. Hands and feet warm; capillary refill brisk. Alert and fully oriented.

Home medications (reconciled with the wife at 22:10).

The wife says he takes "nothing else." Nobody asks about the farm store yet.

First results at 22:30 (full table in Part 2): Na 127, K 5.3, HCO₃ 20, BUN 52, creatinine 2.6 (his baseline), glucose 148. ECG: atrial fibrillation at 88, no peaked T waves, QRS 96 ms. Chest film: cardiomegaly, pulmonary vascular congestion, small bilateral pleural effusions.

The ED resident writes: "BUN:Cr 20, Na 127, on Lasix and Jardiance — likely prerenal from over-diuresis. Hold diuretics, 500 mL NS bolus." The admitting hospitalist pauses the order and asks the student what she thinks.

Pause — commit before the reveal

The saline order is cancelled. He is admitted to telemetry with fluid restriction 1.5 L/day, 2 g sodium diet, strict intake and output, daily standing weight, and furosemide 40 mg IV once, then 40 mg IV twice daily — the same milligrams as his home oral dose. Renal ultrasound is ordered for the morning.

Part 2 — Data

Answers for this section: Q6 · Q7

Overnight (Day 1 → Day 2). Urine output 400 mL in the six hours after the 40 mg IV dose. He sleeps two hours in the recliner position.

Day 2, 05:15. The 04:30 BMP is back: creatinine 3.1. At 05:30 the night resident writes "AKI — hold furosemide" and orders a 1 L normal-saline bolus.

Day 2, 06:00. Weight 90.4 kg (down 0.6 kg). JVP 12 cm. Still orthopneic.

Day 2, 07:00 — handoff. The day hospitalist suspends both the hold order and the saline bolus pending the pharmacist's reconciliation and a 2-hour spot urine sodium after the 08:00 dose, so the 08:00 furosemide 40 mg IV dose is given as scheduled.

Day 2, 08:00 — the pharmacist's call. Reconciling with the farm-store receipt the wife brought in: ibuprofen 400 mg, three to four times a day for three weeks for the back pain. It was never on the medication list.

Day 2, 10:00. A spot urine sodium drawn two hours after the 08:00 furosemide 40 mg IV dose returns 28 mmol/L; urine output in those two hours was 180 mL.

Renal ultrasound. Right kidney 9.8 cm, left 9.6 cm, increased cortical echogenicity (chronic disease), no hydronephrosis, no stones. Bladder scan after voiding: 40 mL.

Laboratory data

Urine studies

Urinalysis (admission). Specific gravity 1.012, pH 5.5, protein 2+, glucose 2+ (expected on empagliflozin — the drug works by putting glucose in the urine), blood negative, leukocyte esterase negative, nitrite negative, ketones negative. Microscopy: 0–2 RBC/hpf, 0–2 WBC/hpf, occasional hyaline casts, no granular or muddy-brown casts, no cellular casts, no crystals.

Reading the data in order. Organ → function → mechanism → labs: the heart cannot empty, venous pressure rises, the kidney is congested and the neurohormonal system is on full (urea retained, water retained, sodium avidly reabsorbed). The sediment is bland and the ultrasound shows no obstruction, so this is not intrinsic or post-renal disease — it is a hemodynamic (functional) problem — cardiorenal syndrome type 1, acute heart failure driving acute kidney injury — and the ibuprofen has been pushing on the same lever for three weeks. The anion gap is normal (9–10), the bicarbonate of 20 is the mild non-gap acidosis of CKD G4 that also pushes his potassium up. The hemoglobin of 10.8 is the anemia of CKD; watch it — it should rise as he decongests.

The 2-hour rule. IV furosemide works within 30 minutes and is largely done by two hours. Judge every IV dose at about two hours by urine output and a spot urine sodium: above 70–100 mmol/L is a good response, 50–70 is mild resistance, 20–50 moderate, and below 20 severe. His 28 mmol/L after a dose equal to his home oral dose says the dose never cleared the threshold. In CKD the threshold is higher (less drug reaches the tubule because loop diuretics enter the urine by proximal tubular secretion, which falls with GFR), gut edema makes oral furosemide unreliable (bioavailability 10–100 %), and the NSAID blunts the response further.

Pause — commit before the reveal

Day 2 plan as written at 10:30. Saline cancelled. Ibuprofen stopped; acetaminophen 650 mg every 8 h as needed; topical diclofenac gel to the lumbar area. Furosemide 80 mg IV now, then 80 mg IV twice daily, response judged at two hours each dose. Fluid restriction 1.5 L/day continues. Spironolactone held (K⁺ 5.4, eGFR <30). Sacubitril-valsartan, carvedilol and empagliflozin continued. BMP and magnesium at least twice daily during active escalation; ECG if K⁺ ≥5.5. Day 2 urine output 2.2 L — the doubled dose starting to clear the threshold.

Part 3 — Course and Decisions

Answers for this section: Q8 · Q9 · Q10 · Q11

Day 3, 06:00. Weight 89.0 kg — 5 kg above dry weight. JVP 12 cm, hepatojugular reflux still positive, S3 present, edema 2+ to the knees. He slept flat for the first time in a week, "mostly." Creatinine 3.2 (up 23 % from 2.6), BUN 66, K⁺ 5.6, Na 129, HCO₃ 21, Mg 1.7. ECG: atrial fibrillation at 84, no peaked T waves, QRS 96 ms, unchanged. The morning furosemide dose was increased to 160 mg IV; two hours later the spot urine sodium is 44 mmol/L and two-hour urine output is 150 mL.

The resident who ordered the saline, now off nights, writes on the sign-out: "Cr still climbing on high-dose Lasix — think we are over-diuresing him into prerenal AKI."

Pause — commit before the reveal

Day 3 plan as written at 10:30. Metolazone 5 mg orally 30 minutes before the morning furosemide; furosemide 160 mg IV twice daily continues, judged at two hours each dose; spironolactone stays held; potassium binder started, low-potassium diet, no salt substitutes; sacubitril-valsartan, carvedilol and empagliflozin continue; BMP and magnesium at least twice daily during active escalation; ECG in the morning. Nephrology consulted for diuretic resistance (spot urine sodium 44 after 160 mg IV, K⁺ 5.6, creatinine 3.2).

Days 3–6.

*A hemoglobin that rises during diuresis is hemoconcentration — the plasma volume shrinking around the same red cells — and is a sign of effective decongestion, not of new red-cell production.

The hemoconcentration, the falling JVP and the falling NT-proBNP (9,800 → 3,900 pg/mL on Day 5) all say the same thing: decongestion worked, and the creatinine turned the corner as it did. Metolazone is stopped on Day 5 at 85.6 kg. On Day 6 he is converted to torsemide 40 mg orally once daily — a maintenance dose, deliberately far below the decongestion dose now that he is at dry weight and off the NSAID, about twice the potency of the home furosemide 40 mg that failed him, with more predictable absorption; the heart-failure clinic titrates it against daily weights. Room air saturation 95 %, sleeping on one pillow.

Discharge planning conference, Day 6. The hospitalist: "His eGFR is 26 and he'll be on dialysis within a couple of years. I'd simplify — stop the Entresto and the Jardiance, keep the torsemide, and let nephrology sort the rest out."

Resolution and Teaching Points

Answers for this section: Q1 · Q2 · Q3 · Q4 · Q5 · Q6 · Q7 · Q8 · Q9 · Q10 · Q11

Mr. V. went home on Day 6 at 84.6 kg with a written plan: weigh every morning before breakfast and call the heart-failure clinic if the weight rises by 1 kg overnight, by more than 2 kg across a week, or if he needs the recliner again. Torsemide 40 mg daily, sacubitril-valsartan 49/51 mg twice daily, carvedilol 12.5 mg twice daily, empagliflozin 10 mg daily, apixaban 5 mg twice daily, atorvastatin 40 mg nightly, insulin glargine 16 units nightly (eating less salt and less in general), acetaminophen and topical diclofenac for the back. Spironolactone is off the list, with the reason written on it. Ibuprofen is on the "never again" line with the mechanism in one sentence. BMP and magnesium in one week; heart-failure clinic in seven days; nephrology in three weeks.

Apixaban. With a CrCl in the 25–30 mL/min range, a student will ask whether the apixaban dose changes. The handout's table retains apixaban 5 mg twice daily at eGFR 15–29 (with caution) and avoids it below 15; the label's own dose-reduction rule (2.5 mg twice daily) turns on patient criteria — age ≥80, weight ≤60 kg, serum creatinine ≥1.5 mg/dL, two of three required — and he meets only the creatinine criterion, so 5 mg twice daily stands. Pharmacy confirms it at discharge. Apixaban is the direct oral anticoagulant (DOAC) least dependent on the kidney (about 25 % renal clearance), which is why it is the usual choice in CKD G4.

Sick-day rules (SADMANS: Sulfonylureas, ACE inhibitors, Diuretics, Metformin, ARBs and ARNI, NSAIDs, SGLT2 inhibitors, plus the mineralocorticoid antagonists spironolactone, eplerenone and finerenone), written for the farmer and his wife. On a day of vomiting, diarrhea, fever or not eating: hold the SGLT2 inhibitor, ARNI, diuretic and (if ever restarted) MRA; never take an NSAID; call the clinic the same day; restart when eating and drinking normally and the clinic has checked a BMP. The beta-blocker is never stopped on his own. The statin continues.

Three weeks later at nephrology: weight 84.2 kg, creatinine 2.7, K⁺ 4.6, Na 134, Mg 2.0, Hgb 11.4. Back pain settled with physical therapy and the topical gel. The dialysis conversation is started — as education, not as a reason to take away a single heart-failure drug.

Clinical Pearl — The volume exam outranks the BUN:Cr ratio JVP, hepatojugular reflux, S3, weight against a known dry weight, and edema decide whether a creatinine rise means congestion or depletion. A ratio of 20 shows up in both. Decide from the neck, not the ratio.

Clinical Pearl — Judge a loop diuretic at two hours, and dose above the threshold IV furosemide is working or not by two hours: urine output and a spot urine sodium below 50–70 mmol/L mean the dose did not clear the threshold — double it. In CKD G4 start at about twice the home oral dose, IV, because gut edema makes oral furosemide unreliable and less drug reaches the tubule at low GFR.

Clinical Pearl — A creatinine rise during decongestion is a cost, not a stop sign Modest creatinine rises can occur during successful decongestion. The percentage alone cannot establish safety or exclude tubular injury; judge perfusion, congestion, urine output and the continuing trend.

Clinical Pearl — Metolazone requires close electrolyte monitoring Loop plus thiazide-like diuretic breaks the braking phenomenon and still works at low GFR, but potassium, magnesium and sodium fall fast. BMP and magnesium at least twice daily during active escalation while on it; replace magnesium below 1.7; stop it at dry weight.

Clinical Pearl — GDMT in CKD is adjusted, not abandoned Continue indicated heart-failure treatment as tolerated, with explicit potassium, renal and hemodynamic monitoring. Temporarily withhold SGLT2 inhibitors during critical illness, fasting or ketosis risk. Initiate steroidal MRA only with eGFR >30 and K <5.0. This patient has established ASCVD from his prior MI and needs secondary prevention; CKD by itself is not the same diagnosis.

Pitfall — Saline for a high creatinine in a patient with a JVP of 12 The single most common wrong move in cardiorenal syndrome. It adds congestion, drops the sodium (saline paradox when urine osmolality exceeds about 300), and delays the only treatment that lowers the creatinine: decongestion.

Pitfall — The medicine that is not on the list Three weeks of over-the-counter ibuprofen explained the extra creatinine, the blunted diuretic response and part of the potassium. Ask every heart-failure and CKD patient, by name, about NSAIDs from the farm store, the gas station and the medicine cabinet — and write the alternatives (acetaminophen, topical NSAID) on the discharge sheet.

Concept Links

Answers for this section: Q1 · Q2 · Q3 · Q4 · Q5 · Q6 · Q7 · Q8 · Q9 · Q10 · Q11

Assigned reading: the explanations in this case and the question-linked course evidence guide. The objective map distinguishes tested decisions from concepts taught in explanations.

Concepts: aki-19, ckd-17, ckd-26, htn-cardiorenal-09, htn-cardiorenal-19, htn-cardiorenal-20, htn-cardiorenal-21, htn-cardiorenal-22, htn-cardiorenal-23, lytes-01, lytes-07, lytes-27, structural-20.