Hypervolemia

Hypervolaemia (volume overload) is an excess of total body sodium and water expanding the extracellular fluid, producing oedema, effusions and congestion.

• Causes:
  • Cardiac: heart failure, valvular disease, constrictive pericarditis.
  • Renal: acute and chronic kidney disease, nephrotic and nephritic syndromes, oliguria.
  • Hepatic: cirrhosis with ascites.
  • Iatrogenic: excessive IV fluids and blood products, sodium-containing medications.
  • Endocrine/other: hyperaldosteronism, Cushing syndrome, drugs (NSAIDs, steroids, glitazones, calcium channel blockers, minoxidil), pregnancy, hypoalbuminaemia, capillary leak.
• Pathophysiology: renal sodium retention from effective arterial underfilling (neurohormonal activation of RAAS, sympathetic system and ADH) or primary renal sodium retention.
• Complications: pulmonary oedema, pleural effusions, ascites, hypertension, hyponatraemia, abdominal compartment syndrome, impaired wound healing, ventilatory failure.

• Weight gain, peripheral pitting oedema, ascites, raised jugular venous pressure, hepatomegaly with hepatojugular reflux.
• Dyspnoea, orthopnoea, crackles, S3, pleural effusions, hypertension.
• Anasarca in severe disease.
• Signs of the cause: cardiomyopathy, jaundice and spider naevi, periorbital oedema, oliguria.
• Hyponatraemia (dilutional) frequent.

• Clinical assessment of volume status (JVP, oedema, weight trends, orthostatic changes).
• Laboratory: sodium, creatinine, urea, albumin, liver tests, urinalysis with protein, spot urine protein/creatinine, urine sodium (under 20–30 mmol/L suggests avid renal sodium retention), BNP/NT-proBNP, TSH.
• Imaging: chest radiograph (congestion, effusions), echocardiography (ventricular function, IVC size and collapsibility, filling pressures), lung ultrasound (B-lines), abdominal ultrasound (ascites, liver, kidneys).
• Venous congestion assessment: VExUS (hepatic, portal, renal vein Doppler).
• Establish cause: cardiac, renal, liver, nephrotic assessment.

• Treat the underlying cause (heart failure therapy, cirrhosis management, immunosuppression for glomerular disease).
• Sodium restriction (2 g/day, 1 g in refractory) and, if hyponatraemic, fluid restriction (1–1.5 L/day).
• Loop diuretics: furosemide 20–80 mg orally twice daily (IV 40–120 mg bolus or infusion 5–20 mg/h in acute decompensation), torsemide 10–40 mg daily, bumetanide 1–4 mg; adjust to weight loss of 0.5–1 kg/day (up to 0.5 kg/day in ascites without oedema).
• Sequential nephron blockade for resistance: metolazone 2.5–10 mg, chlorthalidone 12.5–50 mg, spironolactone 50–200 mg (or eplerenone), acetazolamide 250–500 mg, SGLT2 inhibitors (empagliflozin 10 mg, dapagliflozin 10 mg).
• Cirrhotic ascites: spironolactone 100 mg with furosemide 40 mg (ratio 100:40), titrated to 400:160 mg; large volume paracentesis with albumin 6–8 g per litre removed; TIPS for refractory.
• Nephrotic syndrome: loop diuretic plus thiazide, albumin infusion only in severe hypovolaemic conditions.
• Ultrafiltration or renal replacement therapy for refractory overload with renal failure.
• Avoid NSAIDs, glitazones, and offending drugs; remove unnecessary IV fluids.
• Monitor daily weights, intake/output, electrolytes, creatinine (accept modest rise during effective decongestion).