A study on oedema mechanism in nephrotic syndrome

Colloid osmotic pressure in plasma (COPp) and interstitial fluid (COPi), plasma volume (PV) and interstitial fluid volume (IFV) were measured in 14 patients with hypoproteinaemia due to glomerulonephritis and in five healthy controls. In controls, COPp averaged 24.2 mmHg and COPi 12.0 mmHg. In patients with COPp above 12 mmHg, COPi was reduced nearly identical to the fall in COPp. The transcapillary COP gradient (COPp-COPi) was maintained, and PV and IFV were unchanged. When COPp was reduced below 12 mmHg, the transcapillary COP gradient was decreased. Both IFV increased and renal fluid retention occurred. This study demonstrates the relationship between COPp, transcapillary fluid transport, and renal fluid retention in nephrotic syndrome.