🔹 CASE 1: Acute Kidney Injury (AKI) – Pre-Renal (Cardiology & Internal Medicine)
📌 Case:
A 65-year-old male with chronic hypertension and heart failure presents with fatigue, oliguria (urine output < 400 mL/day), and dizziness for 2 days. He reports poor oral intake and vomiting.
🔹 Lab Results (KFT):
| Parameter | Value | Normal Range |
|---|---|---|
| Serum Creatinine | 2.1 mg/dL | 0.6 – 1.2 mg/dL |
| BUN | 48 mg/dL | 7 – 20 mg/dL |
| BUN/Creatinine Ratio | 23:1 | 10:1 – 20:1 |
| Urine Sodium (UNa) | 8 mEq/L | <20 (Pre-Renal), >40 (ATN) |
| Fractional Excretion of Na⁺ (FENa%) | 0.5% | <1% (Pre-Renal), >2% (ATN) |
🔹 Interpretation:
- ↑ BUN & Creatinine with BUN/Cr >20:1 → Suggests Pre-Renal AKI
- ↓ Urine Sodium (<10 mEq/L) & FENa <1% → Suggests volume depletion (dehydration, heart failure exacerbation)
🔹 Diagnosis: Pre-Renal Acute Kidney Injury (Due to Dehydration & Heart Failure Exacerbation)
🔹 CASE 2: Acute Tubular Necrosis (ATN) – Post-Surgery (Surgical & Emergency Medicine)
📌 Case:
A 45-year-old male underwent major abdominal surgery with significant blood loss and hypotension during the procedure. He developed low urine output and swelling postoperatively.
🔹 Lab Results (KFT):
| Parameter | Value | Normal Range |
|---|---|---|
| Serum Creatinine | 3.8 mg/dL | 0.6 – 1.2 mg/dL |
| BUN | 40 mg/dL | 7 – 20 mg/dL |
| BUN/Creatinine Ratio | 10:1 | 10:1 – 20:1 |
| Urine Sodium (UNa) | 48 mEq/L | <20 (Pre-Renal), >40 (ATN) |
| Fractional Excretion of Na⁺ (FENa%) | 3.5% | <1% (Pre-Renal), >2% (ATN) |
| Urine Microscopy | Granular “Muddy Brown” Casts | Normal (No Casts) |
🔹 Interpretation:
- BUN/Cr <15:1, High Urine Sodium (>40 mEq/L), FENa >2% → Suggests Intrinsic AKI
- Urine Sediment with Muddy Brown Casts → Suggests Acute Tubular Necrosis (ATN)
🔹 Diagnosis: Acute Tubular Necrosis (ATN) Secondary to Ischemia from Hypotension during Surgery
🔹 CASE 3: Chronic Kidney Disease (CKD) – Diabetic Nephropathy (Endocrinology & Nephrology)
📌 Case:
A 55-year-old male with a 10-year history of diabetes mellitus & hypertension presents with fatigue, leg swelling, and foamy urine.
🔹 Lab Results (KFT):
| Parameter | Value | Normal Range |
|---|---|---|
| Serum Creatinine | 2.8 mg/dL | 0.6 – 1.2 mg/dL |
| BUN | 32 mg/dL | 7 – 20 mg/dL |
| GFR (eGFR) | 35 mL/min | >90 mL/min |
| Urine Albumin/Creatinine Ratio | 450 mg/g | <30 mg/g |
| Serum Potassium | 5.6 mEq/L | 3.5 – 5.0 mEq/L |
| Serum Bicarbonate | 18 mEq/L | 22 – 28 mEq/L |
🔹 Interpretation:
- ↓ GFR (35 mL/min) & ↑ Creatinine (2.8 mg/dL) → Suggests Moderate CKD (Stage 3b)
- **↑ Urine Albumin (>300 mg/g) → Suggests Diabetic Nephropathy
- Hyperkalemia & Metabolic Acidosis → Consistent with advanced CKD
🔹 Diagnosis: Chronic Kidney Disease (Stage 3b) Due to Diabetic Nephropathy
🔹 CASE 4: Glomerulonephritis – Pediatric Nephrology
📌 Case:
A 10-year-old boy presents with puffy eyes, cola-colored urine, and high blood pressure 2 weeks after a throat infection.
🔹 Lab Results (KFT & Urine Analysis):
| Parameter | Value | Normal Range |
|---|---|---|
| Serum Creatinine | 1.6 mg/dL | 0.3 – 0.7 mg/dL (Children) |
| BUN | 24 mg/dL | 7 – 20 mg/dL |
| Urinalysis | RBC Casts, Proteinuria (3+) | No Casts, <150 mg/day |
| ASO Titer | Positive | Negative |
| C3 Complement | Low | Normal |
🔹 Interpretation:
- Cola-colored urine + RBC Casts → Glomerular origin
- Recent Strep Infection + Low C3 + ASO Positive → Post-Streptococcal Glomerulonephritis (PSGN)
🔹 Diagnosis: Post-Streptococcal Glomerulonephritis (PSGN)
🔹 CASE 5: Obstructive Uropathy – Urology & Geriatrics
📌 Case:
A 75-year-old male with benign prostatic hyperplasia (BPH) presents with difficulty urinating, flank pain, and high blood pressure.
🔹 Lab Results (KFT):
| Parameter | Value | Normal Range |
|---|---|---|
| Serum Creatinine | 3.0 mg/dL | 0.6 – 1.2 mg/dL |
| BUN | 35 mg/dL | 7 – 20 mg/dL |
| BUN/Creatinine Ratio | 12:1 | 10:1 – 20:1 |
| Bladder Ultrasound | Post-Void Residual >300 mL | <50 mL |
| Renal Ultrasound | Bilateral Hydronephrosis | Normal |
🔹 Interpretation:
- ↑ Creatinine, Bilateral Hydronephrosis, Large Bladder Residual → Post-Renal AKI (Obstructive Uropathy due to BPH)
🔹 Diagnosis: Obstructive Uropathy Secondary to BPH
🔹 SUMMARY TABLE OF CASES
| Case | Diagnosis | Key Findings |
|---|---|---|
| Case 1 | Pre-Renal AKI | High BUN/Cr, Low Urine Na |
| Case 2 | ATN (Post-Surgery) | Muddy Brown Casts, High Urine Na |
| Case 3 | CKD (Diabetes) | Low GFR, Proteinuria |
| Case 4 | Glomerulonephritis (PSGN) | RBC Casts, Low C3 |
| Case 5 | Obstructive Uropathy (BPH) | Hydronephrosis, High Post-Void Residual |
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