This document discusses the clinical approach to a patient presenting with generalized edema. It defines edema and discusses mechanisms that can cause fluid accumulation. The main causes of generalized edema are cardiac (congestive heart failure), renal (nephrotic syndrome), hepatic (liver cirrhosis), nutritional (malnutrition), allergic reactions, and drugs. Investigations and treatment focus on identifying the underlying cause and using diuretics and fluid restriction to increase excretion of sodium and water. Diuretic classes - thiazides, loops, and potassium-sparing - are described along with their mechanisms, indications, side effects and contraindications. Diuretic resistance and its management are also covered.

1. Clinical approach to a patient with generalized oedema

2. IntroductionOedemaisdefined as the accumulation of abnormallyexcessfluid in the interstitialspaces.It canbeclassified as eithergeneralized or localized. (In thispresentationwewilldiscussgeneralizedoedema).Oedemacanalsobeclassified as pitting and non-pitting.

3. Mechanisms maintaining Interstitial Fluid VolumeThe volume of interstitial fluid is determined by Starling's law: Hydrostatic pressure - Oncotic pressure = Net fluid movement out of capillary into the interstitium

4. Mechanisms maintaining Interstitial Fluid Volume[Oncotic pressure = osmotic pressure created by plasma protein molecules (P) that are impermeable across the capillary membrane].

5. Etiology of generalized oedemaDecreased plasma oncotic pressure: due to depletion of plasma proteins. This occurs in nephrotic syndrome, liver failure and malnutrition.Obstruction of lymphatic flow: this occurs in congestive heart failure.

6. Etiology of generalized oedema3. Increased small vessel permeability: due to release of chemical mediators. Plasma proteins (P) leave the circulation and draws more water in the interstitial spaces. This occurs in allergic reactions as anaphylaxis, asthma, hay fever.

7. Etiology of generalized oedema4. Increased hydrostatic pressure: this causes more water to be driven outwards in the interstitial spaces. This occurs in congestive heart failure, liver cirrhosis, renal disease.

8. To sum up… The causes of generalizedoedema are:Cardiac cause: Congestive heartfailure.Renal cause: Nephrotic syndrome.Hepatic cause: Livercirrhosis.Nutritional cause: Malnutrition.Allergicreaction.Drug-induced.

9. Oedema of cardiac originIn congestive heart failure, there is an increase in the central venous pressure. Besides, there is a decrease in renal perfusion which leads to:Renin

10. Renal vasoconstriction

11. ADHNet result is an increase in hydrostatic pressure

12. Oedema of cardiac originCharacteristics of oedema of cardiac origin:- Occurs in the lower extremities.Symmetrical location.

13. Painless, pitting.

14. The presence of a heart disease: dyspnea, cardiac enlargement, hepatomegaly (tender).

15. There can be an elevated jugular venous pressure.Oedema of renal originNephrotic syndrome is defined as a glomerular disease that results in proteinuria(urinary protein loss of ≥ 3.5 gm/day), hypoproteinemia, oedema, and hyperlipidemia.

16. Hypoalbuminemia due to urinary protein losses favors fluid movement from the intravascular to the interstitial compartment and exacerbates oedema formation in the nephrotic syndrome.

17. In some patients, urinary protein loss and hypoalbuminemia can be so severe that plasma volume becomes reduced, leading to renal hypoperfusion and further stimulating sodium and water retention.Oedema of renal originCharacteristics of oedema of renal origin:Mainly due to hypoalbuminemia and salt/water retention.- Associated with hematuria, proteinuria, hypertension and impaired renal functions.- Associated with: puffiness of the face and prominent in the periorbital areas.

18. Cardiac / Renal diseaseCardiac RenalStarts from the lower part of the body.Slow progression.Signs of heart failure: cardiac enlargement, venous distension, hepatomegaly.Starts from the face and periorbital areas.Quick progression.Proteinuria, hypertension, impaired renal function tests.Location:Progression:Other signs:

19. Oedema of hepatic originLiver cirrhosis is defined as increased fibrous tissue in the liver associated with regeneration of focal areas of damaged liver parenchyma.

20. If severe, scarring and distortion of normal liver architecture can lead to marked hepatic dysfunction. This leads to a decrease in plasma protein production from the liver.

21. This, in turn, can cause sodium retention and oedema formation.

22. It appears that the damaged liver fails to degrade or overproduces vasodilating factors. This activates compensatory mechanisms such as sympathetic nerves and the renin-angiotensin-aldosterone system.Oedema of hepatic originCharacteristics of oedema of hepatic origin:- Clinical evidence of hepatic disease as spider angioma , jaundice , ascites (refractory to treatment).

23. Drug-induced oedemaSome drugs can lead to oedema as:Non-steroidal inflammatory drugs.

24. Antihypertensive drugs: calcium channel blockers, alpha-adrenergic antagonists.

25. Steroid hormones.

26. Cyclosporine.

27. Growth hormone.InvestigationsUrine Analysis

28. Heavy proteinuria with nephrotic syndrome.

29. FBC

30. Hb decreased in malabsorption.