Edematous Diseases

1. Edematous Diseases May 3, 2013 Neil A Kurtzman, MD

3. Edema • CHF • AGN • Nephrotic Syndrome • Cirrhosis

4. Irrespective of disease, the cause of edema is always renal salt retention

5. John Peters – 1948 • A normal kidney retains salt in patients with CHF • Volume must be contracted

6. The kidney retains salt when volume is contracted • It excretes salt when volume is expanded • What is the volume compartment the kidney recognizes?

7. Volume Candidates • Blood volume • Interstitial volume • Extracellular volume

8. Peters invented a volume compartment EABV

9. Effective Arterial Blood Volume • A concept not a measurable entity • Normal EABV is that amount of arterial filling that assures adequate organ perfusion • Its state is inferred from history, PE, and lab values

10. EABV • Vomiting • Diarrhea • Sweating • Hemorrhage • CHF • Some forms of nephrotic syndrome • Cirrhosis

11. EABV • History • PE – BP • Low urine Na • High uric acid • Increased BUN:Cr

12. CHF • CO inadequate • Circulation underfilled • EABV decreased • Kidney retains salt and water • Edema

13. AGN vs CHF Edema + Pulmonary Edema + Urine Na Low CVP High Heart size Increased S3 + EDP High ______________________________________ These patients have different diseases

14. AGN vs CHF (cont) AGNCHF BP rises falls Facial edema + - Renin low high Aldosterone low high AVP low high

15. AGN vs CHF (cont) AGN CHF Digitalis - + CO high low A-V O2 Δ low high A-V pH Δ low high

16. Characteristics of Edematous Diseases PrimarySecondary Nephritic CHF Renal Failure Cirrhosis NS NS ECF vol high high Plasma vol high high BP high low CO high low to high

17. Characteristics of Edematous Diseases 2 Primary Secondary Nephritic CHF Renal Failure Cirrhosis NS NS GFR low* low RBF nl* lower FF low high Renin low high Aldo low high

18. Characteristics of Edematous Diseases 3 PrimarySecondary Nephritic CHF Renal Failure Cirrhosis NS NS SNS activity Nl Increased ADH Low High FNa Excretion Low Low

19. Primary Salt Retention EABV Salt retention Renin Aldo AVP BP Edema

20. Consequences of Primary Salt Retention • Facial edema • Normal Na • Hypertension

21. SecondarySalt Retention

22. Consequences of Secondary Salt Retention • Dependent edema • Hyponatremia • BP falls • Hypokalemia • Metabolic alkalosis

23. Nephrotic Syndrome – Low EABV • Plasma volume may be reduced • High renin • Renal underperfusion • Increased Na excretion after vol expansion or water immersion • Increased SNS activity • BP rises after remission

24. Nephrotic Syndrome – High EABV • Plasma vol nl or increased • Low renin • No response to vol expansion • Low FF • BP falls after remission

25. Implications for Diuretic Rx • Patients with nephritic edema will respond • CHF – depends on Starling curve • NS will respond if EABV is high • Cirrhosis - rarely does any good

26. Conclusions • Edema always results from renal salt retention • Primary edema – EABV is expanded • Secondary edema – contracted EABV cause the salt retention

28. SecondarySalt Retention

29. Characteristics of Edematous Diseases ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ PrimarySecondary Nephritic CHF Renal Failure Cirrhosis NS NS ECF vol high high Plasma vol high high BP high low CO high low to high

30. Characteristics of Edematous Diseases ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ PrimarySecondary Nephritic CHF Renal Failure Cirrhosis NS NS GFR low* low RBF nl* lower FF low high Renin low high Aldo low high

31. Characteristics of Edematous Diseases ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ PrimarySecondary Nephritic CHF Renal Failure Cirrhosis NS NS SNS activity Nl Increased ADH Low High FNa Excretion Low Low