Case 04: The Tired Teacher

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Session S2 · 2026-10-27 · in-session · 37 min Anchor: Chronic kidney disease — staging, cause, anemia and blood pressure · Integrates: Hypertension (measurement, home BP, targets, resistant HTN, agent choice, lifestyle), NSAIDs, metabolic acidosis of CKD, MBD screen, referral One-line hook: A new PA inherits hundreds of charts that say "hypertensive kidney disease," and most of those patients are tired, on three blood-pressure pills, and quietly taking ibuprofen. This case is how you take that chart apart in one visit: measure the pressure properly, stage the kidney, question the label, find the iron, and know what is yours and what is nephrology's.

Learning Objectives

Answers for this section: Q1 · Q2 · Q3 · Q4 · Q5 · Q6 · Q7 · Q8 · Q9 · Q10 · Q11 · Q12 · Q13

• Recognize a non-standardized office blood pressure, remeasure it correctly, and prescribe the 7-day home blood pressure protocol before changing any drug.
• Place a patient on the KDIGO heat map from eGFR and UACR (the ratio, not the dipstick), prove chronicity from a prior creatinine, and state what the color means for monitoring and referral.
• Order and interpret the first-line work-up for the cause of CKD (urinalysis with microscopy, repeat UACR, renal ultrasound), and name the findings that fit, and the findings that un-fit, hypertensive nephrosclerosis.
• Work the complication labs of G3b in order: iron studies and a search for blood loss before "anemia of CKD"; oral bicarbonate for a bicarbonate that stays below 22 (the long-standing practice threshold — KDIGO 2024 individualizes); nutritional vitamin D and dietary phosphorus for the mineral-bone screen — and say which decisions (ESA, active vitamin D, binders) belong to nephrology.
• Define resistant hypertension, exclude pseudoresistance (technique, adherence, white-coat effect, sub-maximal dosing), remove the NSAID, choose the right diuretic, explain why spironolactone and a second RAAS blocker are off the table at eGFR 34, and refer with the right data.

Warm-Up (individual commit before the case)

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Three readiness items. Cards up, individually, before any discussion. These check vocabulary the case needs; they do not grade reasoning.

Part 1 — Presentation

Answers for this section: Q4 · Q5 · Q6

Ms. Carol Jensen, 58, teaches seventh-grade science. Chief complaint, in her words: "I'm tired all the time, and it's October."

History of present illness. Four months of fatigue that gets worse through the school day. By fifth period she sits between classes, which she never used to do. The two flights of stairs to her classroom leave her short of breath where last spring they did not. Her legs feel "jumpy" at night and she has trouble keeping them still. No chest pain, no orthopnea, no leg swelling beyond the ankle puffiness she has had since the amlodipine was started. No gross hematuria (visible blood in the urine), no dysuria, no flank pain. Stools "look normal" as far as she has noticed; no vomiting, no black stools she is aware of. Postmenopausal for five years. Appetite fine, weight stable. She came straight from fifth period, parked two blocks away, took the stairs, and was describing the science fair when the medical assistant put the cuff on.

Past medical history. Hypertension for 15 years, diagnosed at 43. "Hypertensive kidney disease" — a label added two years ago when a creatinine of 1.6 mg/dL turned up on a pre-operative panel for knee arthroscopy; the arthroscopy was cancelled and nobody followed up the kidney. Osteoarthritis of both knees. Hyperlipidemia. No diabetes (hemoglobin A1c 5.6 % last year). No kidney stones, no urinary infections, no gout.

Family history. Mother: hypertension, "kidney trouble" in her 80s, never on dialysis. Father: myocardial infarction at 70. Nobody on dialysis before old age, no polycystic kidneys, no deafness, no family hematuria.

Social history. Lives with her husband; two grown children. Never smoked. Two or three glasses of wine a week. Exercise: "not much — the knees." Diet: cafeteria lunches, frozen dinners, a diet cola most afternoons.

Medications as charted.

Allergies: none known.

Vitals. BP 158/94 mmHg — right arm, seated on the exam table with feet dangling, standard adult cuff, taken within two minutes of arrival while she talked. Heart rate 88. Respiratory rate 14. Temp 36.8 °C. SpO₂ 98 % on room air. Weight 84 kg, height 165 cm, BMI 30.9 kg/m². Mid-arm circumference 35 cm.

Examination. Pale conjunctivae. No jugular venous distension. Lungs clear. Heart regular, no murmur, no S3. Abdomen soft, no bruit. Trace bilateral ankle edema. Knees: crepitus, no effusion, no warmth. Fundi: arteriolar narrowing, no hemorrhages or exudates. Neurologically intact. ECG: sinus rhythm 84, left ventricular hypertrophy by voltage.

What the chart already holds. One creatinine of 1.6 mg/dL (August 2024, eGFR 38 at age 56). One UACR of 150 mg/g (2024). No urinalysis with microscopy, ever. No kidney imaging, ever.

Before the questions, the vocabulary. Two numbers stage a kidney. The eGFR says how fast it filters. The UACR — the urine albumin-to-creatinine ratio, measured on a spot sample — says how much albumin is leaking through the filter; it is corrected to creatinine so dilution does not fool you. KDIGO puts the two on a grid: G1–G5 for filtration, A1–A3 for albumin, with a color for the combined risk. The grid, not the label on the chart, is where this visit starts.

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Part 2 — Data

Answers for this section: Q7 · Q8 · Q9

Labs drawn fasting the morning after the visit; the urinalysis is a first-morning specimen; the ultrasound was done the same week. Reference ranges are the lab's.

Chemistry

Prior, for the trend (August 2024): creatinine 1.6 mg/dL, eGFR 38, BUN 22 mg/dL, potassium 4.4 mEq/L, bicarbonate 22 mEq/L.

Hematology and iron

Urinalysis (first-morning, clean catch)

UACR: 180 mg/g (visit); repeat three weeks later, first-morning: 164 mg/g. Both A2.

Renal ultrasound: right kidney 10.2 cm, left 10.0 cm; cortical echogenicity mildly increased bilaterally, cortical thickness preserved; no hydronephrosis, no stones, no cysts or masses; bladder normal, post-void residual 20 mL.

Read it the way the kidney works. The filter: eGFR 34, stable-slow, bland urine, two smooth symmetric kidneys of normal length — the structural picture of a chronic, slow process with nothing active. Notice the dipstick: trace protein against a UACR of 180 mg/g — the strip misses A2 albuminuria (Q3), which is why the ratio, not the dipstick, stages her. The acid handling: a bicarbonate of 19 with a normal anion gap, because a kidney with a third of its nephrons left cannot excrete the day's acid load as ammonium. The hormone jobs: erythropoietin (the kidney's signal to the marrow to make red cells) and activation of vitamin D both fall with nephron mass, and phosphate retention pushes PTH up.

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Part 3 — Course and Decisions

Answers for this section: Q10 · Q11 · Q12

Three weeks later, at the follow-up visit, the anemia results are the first thing you open.

Then the other two results.

The medication-reconciliation call. The nurse asks the question the intake form did not: "What do you take for your knees?" Ibuprofen 600 mg, one tablet most school mornings, sometimes a second after dismissal, for about three years — "from the big bottle at home; it isn't a prescription, so I didn't write it down." That is a non-steroidal anti-inflammatory drug (NSAID) roughly five days a week in a woman with an eGFR of 34, on a full-dose ACE inhibitor and a diuretic.

The home blood pressure log. Morning and evening, two readings each, seven days; day 1 discarded; 24 readings averaged: 144/88 mmHg. Pharmacy refill history: all three antihypertensives filled on time for the last 12 months. The repeat UACR was 164 mg/g.

Put the three together. Her hypertension is real (home average well over 130/80, so not white-coat), she is adherent, all three drugs are at maximal dose, and she is above goal on three drugs including a diuretic — the definition of resistant hypertension, with the pseudoresistance list (technique, adherence, white-coat effect, sub-maximal dosing) now fully worked. And standing in the middle of it is a drug that does three things to a kidney at once. Prostaglandins keep the afferent arteriole (the inflow vessel to each glomerulus) open and help the kidney excrete sodium. Block them with an NSAID and filtration falls — a hemodynamic, reversible drop in GFR — the kidney holds sodium, which raises blood pressure and blunts the diuretic and the ACE inhibitor, and potassium excretion falls. With an ACE inhibitor (which relaxes the outflow vessel) and a diuretic (which lowers the volume coming in) on board, that is the "triple whammy." The same drug erodes the stomach lining, and a stomach that bleeds a little every day is how a postmenopausal woman loses iron without ever seeing a black stool.

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Self-study checkpoint — after class

Answers for this section: Q13

This additional question is completed after class and does not extend the timed run sheet.

Resolution and Teaching Points

Answers for this section: Q1 · Q2 · Q3 · Q4 · Q5 · Q6 · Q7 · Q8 · Q9 · Q10 · Q11 · Q12 · Q13

The plan from the visit. Ibuprofen stopped; acetaminophen 650 mg PO every six hours as needed (maximum 3 g/day) and diclofenac 1 % gel to both knees four times daily; physical therapy for the knees. Hydrochlorothiazide 25 mg stopped, chlorthalidone 12.5 mg PO daily started, BMP in 10–14 days. Ferrous sulfate 325 mg PO daily on an empty stomach, with the warning about constipation and dark stools. Gastroenterology referral for colonoscopy and upper endoscopy. Sodium bicarbonate 650 mg PO twice daily after the repeat bicarbonate came back 19 again. Cholecalciferol 2,000 IU PO daily. Renal dietitian: DASH pattern (the fruit-vegetable-low-fat-dairy eating pattern), sodium under 2.3 g/day, phosphate additives, no potassium salt substitute. Nephrology referral placed, with the data packet. Repeat 7-day home log in six weeks.

Twelve weeks later. Hemoglobin 10.9 g/dL, MCV 82, ferritin 96, TSAT 21 % — rising about 0.5 g/dL a month, the low end of the 0.5–1 g/dL a month oral iron should give, acceptable while the bleed was being found and stopped. Endoscopy: erosive gastritis consistent with NSAID injury, no ulcer; colonoscopy: one small tubular adenoma, removed, no cancer. Creatinine 1.6 mg/dL (eGFR 37) — the hemodynamic part of the NSAID effect reversed; potassium 4.4; sodium 138 on chlorthalidone; bicarbonate 23. Home average 138/86. Still above goal, so the referral stands. Nephrology confirmed CKD G3b A2, "presumed nephrosclerosis with an NSAID contribution — a label held loosely," agreed no ESA was indicated while the hemoglobin was rising on iron, and started the next layer of kidney protection, which is the next case's business. Spironolactone stayed off the table at eGFR 37. She finished the semester standing up.

Clinical Pearl — A blood pressure taken wrong is a number, not a diagnosis No rest, talking, a small cuff and dangling feet add more than 10 mmHg between them. Remeasure properly, then let a 7-day home average (morning and evening duplicates, discard day 1) make the drug decision. Home readings exclude white-coat hypertension and predict outcomes better than the office.

Clinical Pearl — "Hypertensive kidney disease" is a label you earn by exclusion It fits when the hypertension is long, the urine is bland, the albuminuria is low-grade, the decline is slow and the kidneys are symmetric. A3, hematuria or cellular casts, a fall over 5 mL/min per year, young onset or a family history send you looking for another disease. The first-line work-up is three tests: urinalysis with microscopy, a repeat UACR, a renal ultrasound.

Clinical Pearl — In CKD anemia, iron first — and iron deficiency has a cause Ferritin under 100 with TSAT under 40 means iron in non-dialysis CKD (KDIGO 2026). Microcytosis suggests iron deficiency, which can coexist with erythropoietin deficiency. Iron deficiency after menopause is a gastroenterology referral; a stool blood test cannot confirm or exclude the cause and should not gate indicated GI evaluation. ESAs are nephrology's call, after iron, with the hemoglobin kept under 11.5 g/dL.

Clinical Pearl — The G3b complication labs have owners Primary care can investigate persistent low bicarbonate and nutritional vitamin D deficiency. KDIGO 2024 individualizes acidosis treatment, giving bicarbonate <18 as an example rather than a mandatory cutoff at 22. Monitor blood pressure, volume and potassium if alkali is used. Correct vitamin D deficiency using an appropriate local regimen; avoid a universal 30–100 target. Follow calcium, phosphate and PTH trends; active vitamin D and ESA decisions require individualized specialist review.

Clinical Pearl — Resistant hypertension is a work-up before it is a fourth drug Confirm out-of-office pressure, assess adherence and optimize tolerated therapy, then remove reversible contributors such as oral NSAIDs. Chlorthalidone may be useful with electrolyte monitoring. Spironolactone at eGFR 34 and K 4.6 requires extra caution and specialist advice; the PATHWAY-2 eligibility thresholds are not universal contraindications. Do not combine ACEi and ARB. Use clinical complexity and kidney-failure risk to guide referral.

Pitfall — Treating the stairwell Adding a fourth antihypertensive, or doubling the thiazide, to a 158/94 taken over a sleeve two minutes after a flight of stairs. The patient collects a drug and a side effect; the pressure that was never real "improves."

Pitfall — Calling it "anemia of CKD" and reaching for the ESA A hemoglobin of 9.6 at an eGFR of 34 looks like erythropoietin deficiency until you look at the MCV and the ferritin. Miss the iron deficiency and you miss the bleed behind it — and you give a thrombotic drug to a marrow that cannot use it.

Concept Links

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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: ckd-01, ckd-02, ckd-03, ckd-04, ckd-05, ckd-07, ckd-10, ckd-14, ckd-15, ckd-16, ckd-19, ckd-21, ckd-26, htn-cardiorenal-01, htn-cardiorenal-02, htn-cardiorenal-04, htn-cardiorenal-06, htn-cardiorenal-10, htn-cardiorenal-16, structural-20.