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Tissue Fluid Formation and Oedema

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Presentation on theme: "Tissue Fluid Formation and Oedema"— Presentation transcript:

1 Tissue Fluid Formation and Oedema
Leicester Warwick Medical School Tissue Fluid Formation and Oedema Dr. Kevin West Department of Pathology


3 Tissue Fluid Formation - Objectives 1
Control of normal interstitial fluid formation Definition of oedema Definition of pleural effusion, pericardial effusion and ascites Distinction between transudate and exudate

4 Tissue Fluid Formation - Objectives 2
Common causes and mechanisms of development of oedema Pulmonary oedema - causes and effects Cerebral oedema - causes and effects

5 Water Major body component 60% male 50% female 3 compartments
intracellular extracellular interstitial extracellular intravascular

6 Osmolality Osmotic pressure related to number of particles of solute Oncotic pressure describes osmotic pressure exerted by proteins Effect of oncotic pressure small but significant across capillaries

7 Control of Interstitial Fluid
Hydrostatic pressure Oncotic pressure Endothelial integrity Lymphatic system

8 Interstitial Fluid Fluid between cells Derived from capillaries Solutes similar to plasma except for protein content

9 Movement Of Fluid Across Capillaries
Capillary (hydrostatic) pressure Interstitial fluid (hydrostatic) pressure Plasma oncotic pressure Interstitial fluid oncotic pressure

10 Capillary Pressure Forces fluid from capillary to interstitium Arterial end higher than venous end Arterial approx. 30 mmHg Venous approx. 10 mm Hg

11 Interstitial Fluid Pressure
Maybe positive or negative Negative - forces fluid into interstitium Positive - forces fluid into capillary Approx. minus 3 mm Hg in loose connective tissue Higher in denser connective tissue

12 Plasma Oncotic Pressure
Proteins are the only solutes which do not pass freely between plasma and interstitium Thus it is only proteins which exert a significant osmotic effect across capillary walls Albumin is the most abundant plasma protein Approx 28 mm Hg (Albumin = 21.8)

13 Interstitial Oncotic Pressure
A small amount of protein is present in the interstitium Tends to force fluid out of capillary Concentration is approx 40 % of that in plasma Approx 8 mm Hg

14 Balance Sheet - Arterial
Outward Cap. pressure Negative interstitial fluid pressure Interstitial oncotic pressure Total Inward Plasma oncotic pressure Net out (Filtration pressure)

15 Balance Sheet - Venous Outward Inward Cap. pressure 10
Negative interstitial fluid pressure Interstitial fluid oncotic presure Total Inward Plasma oncotic pressure Net inward (Reabsorption pressure)

16 Lymphatic System The lymphatic system provides a route for the transport of fluids and protein away from the interstitium System of fine lymphatic channels throughout the body passing via lymph nodes to thoracic duct Valves ensure one-way flow

17 Oedema Hydrostatic pressure Oncotic pressure Endothelial integrity Lymphatic integrity

18 Oedema Definition An increased volume of interstitial fluid in a tissue or organ May be localised or generalised (systemic)

19 Causes of Oedema Raised capillary pressure Reduced oncotic pressure Endothelial damage (inflammation) Impaired lymphatic drainage

20 Raised Capillary Pressure
Cardiac failure right ventricular failure - systemic oedema left ventricular failure - pulmonary oedema congestive cardiac failure - both Local venous obstruction deep vein thrombosis external compression SVC obstruction

21 Reduced Oncotic Pressure
Renal disease loss of albumin across glomerulus Hepatic disease inadequate albumin synthesis Malnutrition

22 Lymphatic Obstruction
Tumours Fibrosis Inflammation Surgery Congenital abnormality

23 Generalised Oedema Congestive cardiac failure Right ventricular failure Renal disease Liver disease

24 Generalised Oedema Commonly causes swelling of ankles
Swelling may extend higher Sacral oedema in recumbent patients

25 Right Ventricular Failure
Raised jugular venous pressure also seen Enlarged liver also common due to congestion (nutmeg liver)

26 Pulmonary Oedema Usually caused by LVF
Raised pressure across pulmonary capillaries Causes shortness of breath Due to ischaemic heart disease or hypertension

27 Pulmonary Oedema

28 Congestive Cardiac Failure
Combination of left and right ventricular failure Common in ischaemic heart disease Causes systemic and pulmonary oedema

29 Cerebral Oedema Causes increased intracranial pressure
Fatal if left untreated Generalised in hypoxia, injury Surrounding other lesions eg tumour, abscess

30 Ascites (peritoneal effusion)
Fluid in Body Cavities Pleural effusion heart failure, inflammation, tumour Pericardial effusion inflammation, tumour Ascites (peritoneal effusion) cirrhosis, heart failure, tumour

31 Pleural Effusion

32 Pericardial Effusion

33 Ascites Most severe cases associated with cirrhosis of the liver
intra-abdominal malignancy


35 Superior Vena Cava Obstruction


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