Oedema, also known as edema, is the abnormal accumulation of fluid in the interstitial spaces or body cavities. It can occur locally in specific areas like the lungs or abdomen, or systemically throughout the body. Oedema is classified as either transudative or exudative based on its fluid composition, and as pitting or non-pitting based on whether the fluid can be displaced by pressure. The main causes of oedema are increased hydrostatic pressure, reduced plasma oncotic pressure, lymphatic obstruction, and inflammation.

1. OEDEMA
Dr. Saugat Chapagain

2. OEDEMA/ EDEMA
 Abnormal and excessive accumulation of free fluid in interstitial
spaces and serous cavities.
 Site:
• In body cavities-
• Ascites, hydrothorax, pleural effusion, pericardial effusion, etc.
• In interstitial space-
• Lies free in the interstitial space.
• Can be displaced with pressure (Pitting)
• Can not be displaced (non pitting) e.g. myxoedema

3. ALL OEDEMA ARE PITTING
EXCEPT ONES DUE TO
LYMPHATIC OBSTRUCTION
AND MYXOEDEMA

4. TYPES
 Based on site/ distribution:
• Localized
• Pulmonary effusion, ascites, hydrothorax, pericardial effusion, lymph
edema, peripheral venous obstruction.
• Generalized (usu. Transudative) (anasarca/ dropsy)
• Renal, cardiac, hepatic, famine(nutritional
 Based on fluid composition:
• Transudate-
• Non inflammatory, usu. Systemic.
• Exudate-
• Inflammatory

5. PATHOGENESIS
 Increased hydrostatic pressure
• Force that drives fluid from capillary into the interstitial space.
• Counteracts plasma oncotic pressure (force that resorbs interstitial fluid)
1. Increased venous return
• CCF, Constrictive pericarditis.
• Venous obstruction, thrombosis, postural
2. Arteriolar dilation
• Heat, neuro-humoral dysregulation
 Reduced plasma oncotic pressure
• Hypoproteinemia, nephritic synd. GN, liver cirrhosis, PEM

6. PATHOGENESIS (CNTD…)
 Lymphatic obstruction
• Inflammatory (filariasis)
• Neoplastic
• Post surgical
• Post radiation
 Tissue factors
• If sc tissues are loose e.g. eyelids in old age
 Sodium and water retention
• Excess salt intake with renal insufficiency
• Increased reabsorption of sodium
 In inflammation