Renal · Year 2 · from Renal

Case 2: CKD with Medication-Related Complications

Patient Presentation

Demographics: 71-year-old female

Chief Complaint: Confusion and weakness for 2 days

History of Present Illness: The patient's daughter brings her to the emergency department because she has been increasingly confused and weak. She has known CKD stage 4 and was recently started on spironolactone for resistant hypertension. She also started taking ibuprofen for knee pain one week ago.

Past Medical History:

  • CKD stage 4 (baseline creatinine 2.8 mg/dL)
  • Hypertensive nephrosclerosis
  • Heart failure with preserved ejection fraction
  • Osteoarthritis

Medications:

  • Lisinopril 40 mg daily
  • Furosemide 40 mg twice daily
  • Spironolactone 25 mg daily (started 2 weeks ago)
  • Ibuprofen 600 mg three times daily (started 1 week ago)
  • Amlodipine 10 mg daily

Physical Examination:

  • Blood pressure: 102/58 mmHg (baseline 140/80)
  • Heart rate: 52 bpm
  • General: Lethargic, confused
  • Cardiovascular: Bradycardic, irregular rhythm
  • Lungs: Clear
  • Extremities: No edema

Workup and Results

Laboratory Studies:

  • Creatinine: 5.2 mg/dL (baseline 2.8)
  • BUN: 78 mg/dL
  • Potassium: 7.4 mEq/L
  • Sodium: 128 mEq/L
  • Bicarbonate: 16 mEq/L

ECG:

  • Peaked T waves
  • Widened QRS complex
  • Heart rate 48 bpm

Clinical Image

Electrocardiogram demonstrating classic findings of severe hyperkalemia: peaked T waves, prolonged PR interval, and widened QRS complex.

Diagnosis

Acute-on-Chronic Kidney Injury with Severe Hyperkalemia

Contributing factors:

  • NSAID use (ibuprofen) reducing renal perfusion
  • Triple whammy: ACE inhibitor + diuretic + NSAID
  • Spironolactone potentiating hyperkalemia

Discussion

This case demonstrates medication-related AKI superimposed on CKD:

  • Triple Whammy Effect: The lecture describes how the combination of ACE inhibitors, diuretics, and NSAIDs creates a "perfect storm" for AKI. NSAIDs block prostaglandin-mediated afferent arteriolar dilation while ACE inhibitors prevent efferent arteriolar constriction, dramatically reducing GFR.
  • Hyperkalemia Mechanisms: Multiple factors contributed: NSAID-induced AKI reducing potassium excretion, spironolactone blocking ENaC-mediated potassium secretion, and ACE inhibitor reducing aldosterone. The lecture notes that potassium-sparing diuretics require careful monitoring in CKD.
  • Life-Threatening Emergency: Potassium above 7.0 mEq/L with ECG changes requires emergent treatment. The wide QRS and peaked T waves indicate cardiac membrane instability.

Treatment Plan

  1. Emergent Hyperkalemia Management:
  • IV calcium gluconate (cardiac membrane stabilization)
  • IV insulin with glucose (shift potassium intracellularly)
  • Sodium bicarbonate (if acidotic)
  • Kayexalate or patiromer (potassium removal)
  • Prepare for emergent hemodialysis if refractory
  1. Medication Discontinuation:
  • Stop ibuprofen immediately
  • Hold spironolactone
  • Hold lisinopril temporarily
  1. Volume Resuscitation:
  • Careful IV fluids (patient has heart failure history)
  1. Long-term Management:
  • Acetaminophen for pain (avoid NSAIDs in CKD)
  • Reassess need for spironolactone
  • Restart ACE inhibitor at lower dose once stable

Teaching Points

  1. NSAIDs should be avoided in CKD due to hemodynamic effects and AKI risk
  2. The "triple whammy" combination greatly increases AKI risk
  3. Hyperkalemia is a medical emergency requiring immediate ECG assessment
  4. Acceptable creatinine rise after ACE inhibitor initiation is up to 30%
  5. Drug dosing must be adjusted for reduced GFR

Image Reference

For visual reference of CKD concepts, see:

Learning Points

  1. CKD Definition: Kidney damage or GFR <60 mL/min/1.73m2 persisting for at least 3 months
  1. Diabetes is #1 Cause: Diabetes mellitus accounts for 40-50% of CKD cases; control proteinuria with RAAS blockade
  1. CKD-MBD Triad: Hyperphosphatemia, hypocalcemia, and secondary hyperparathyroidism require dietary restriction and phosphate binders
  1. Anemia Target: Hemoglobin 10-11.5 g/dL with ESAs; ensure iron repletion first (ferritin >100, TSAT >20%)
  1. Avoid Nephrotoxins: NSAIDs, aminoglycosides, and iodinated contrast require extreme caution or avoidance in CKD

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