A 68-year-old woman with chronic kidney disease (eGFR 28 mL/min/1.73m²) and diabetes presents with acute-onset dyspnoea, orthopnoea, and peripheral oedema. Chest X-ray shows bilateral pulmonary oedema. BNP is 850 pg/mL. Echocardiography reveals ejection fraction 28% with global hypokinesis. Serum creatinine has risen from 2.1 to 3.8 mg/dL over 48 hours. Urine sodium is 15 mEq/L. What is the most appropriate immediate next step in management?

Explanation

## Clinical Scenario Analysis This patient presents with **acute decompensated heart failure (ADHF)** with: - Severe systolic dysfunction (EF 28%) - Acute kidney injury (creatinine rise from 2.1 to 3.8 mg/dL) - Pre-renal features (low urine sodium 15 mEq/L indicates renal hypoperfusion) - Pulmonary oedema (reversible injury to alveolar epithelium) ## Pathophysiology: Reversible vs Irreversible Injury in Heart Failure **Key Point:** In acute decompensated heart failure, the myocardium may show both reversible and irreversible injury: - **Reversible injury:** Myocardial stunning (temporary contractile dysfunction without necrosis), pulmonary oedema (alveolar epithelial injury that resolves with diuresis) - **Irreversible injury:** Myocardial necrosis (if acute coronary syndrome precipitated the decompensation), cardiomyocyte apoptosis in chronic heart failure **High-Yield:** The acute rise in creatinine with low urine sodium indicates **cardiorenal syndrome Type 1** — acute worsening of renal function due to reduced cardiac output and renal hypoperfusion. This is a reversible process if cardiac output is restored urgently. ## Management Priorities in ADHF ```mermaid flowchart TD A["Acute Decompensated<br/>Heart Failure"]:::outcome --> B{"Haemodynamically<br/>stable?"}:::decision B -->|"Yes"| C["IV diuretics<br/>Vasodilators"]:::action B -->|"No (hypotensive)"| D["IV inotropes<br/>± vasopressors"]:::action C --> E{"ACS suspected?"}:::decision D --> E E -->|"Yes"| F["ECG, troponin<br/>Urgent cardiology"]:::action E -->|"No"| G["Echocardiography<br/>Optimise therapy"]:::action F --> H["Coronary angiography"]:::action G --> I["Discharge planning<br/>ACE-I/ARB, beta-blocker"]:::outcome ``` ## Why This Option is Correct 1. **IV diuretics (furosemide)** are the first-line therapy for pulmonary oedema and ADHF to relieve congestion and restore renal perfusion - Dose: 40–80 mg IV bolus, titrate to urine output - Avoid over-diuresis (worsens cardiorenal syndrome) 2. **Inotropic support (dobutamine, milrinone)** if hypotensive or in cardiogenic shock - Improves cardiac output and renal perfusion - Reverses cardiorenal syndrome Type 1 3. **Assess for acute coronary syndrome (ACS)** because: - MI is a common precipitant of acute decompensation - Troponin elevation may indicate myocardial necrosis (irreversible injury) - Early revascularisation improves outcomes 4. **Urgent cardiology consultation** for: - Risk stratification - Consideration of advanced therapies (mechanical support, transplant) - Optimisation of chronic heart failure medications **Clinical Pearl:** The acute rise in creatinine with low urine sodium is **reversible** if cardiac output is restored within 48–72 hours. Delayed intervention risks progression to acute tubular necrosis (irreversible renal injury).