Oedema

 Definition of brief description  of Edema ,Shock ,Haemorrage Embolism ,Ischemia & Infarction:-

Oedema :-

Excess fluid in the body tissue (extra vascularly ) means (excess fluid in the body either inside the cells which is intracellular edema either or in the interstitium in the body cavity which is called extra cellular edema .

                                                Or

Edema is defined as abnormal & excessive accumulation of “free fluid” in interstitial tissue space and serous cavities.

Free fluid in interstitial fluid-

·         It is also called tissue space

·         Its surrounded by tissue cells

·         Interstitial space filled with interstitial fluid provide the immediate micro environment that allow for movement of ions proteins and nutrients across the cell barriers.

·         This fluid lies free in the interstitial space b/w the cells and can be displaced from one place to another place.

·         Free fluids in interstitial space is commonly called oedema.

·         Here two term of edema are used.

Pitting edema :-

Pitting edema is known as momentary pressure of finger produces adepression .

Non pitting edema:-

No pitting depression produced by finger .

Eg.:-  Myoedema  , elephantiasis

Oedema :- two main type of edema

(1) Localized edema

(2)Generalized edema

(1)Localized edema :-

When ever edema is present in limited to an organ or limb.

Eg.:- lymphatic edema , inflammatory edema , allergic edema, pulmonary edema , cerebral edema ,

(2)Generalized edema :-

When it is systemic in distribution ,particularly noticeable in the subcutaneous tissue.

Eg. :- renal edema , cardiac edema , nutritional edema .

Pathogenesis of oedema /causes of edema :-

·         Oedema is caused by mechanism that interfere with normal fluid balance of plasma ,interstitial fluid & lymph flow

·         But here the main causes of edema is due to increased capillary hydrostatic pressure or diminished (decrease ) plasma osmotic pressure resulting increased interstitial fluid

·        Here some factors are effected:-

(1)   Increased capillary hydrostatic pressure

Impaired venous return

Arteriolar dilation.

(2)   Decreased colloid plasma osmotic pressure

(3)   Lymphatic obstruction

(4)   Sodium and water retention

(5)   Inflammation.

(1)Increased capillary hydrostatic pressure:-

·         The hydrostatic pressure of the capillary is the force that normally tends to drive fluid through the capillary wall into the interstitial space by counteracting the force of plasma oncotic pressure

·         Increased hydrostatic pressure are mainly caused by disorder that impaired venous  return.

·         Example of increased capillary hydrostatic pressure seen in some disorders.

(1)   Odeam of cardiac diseases:- eg.:- congestive cardiac failure ,. Constrictive pericarditis

(2)   Ascites of liver disease:- eg.:- ascites , liver cirrhosis.

 

(3)   Passive congestion:- eg. :- mechanical obstruction due to thrombosis of vein of lower legs, vercositien ,pressure by pregnant uterus , tumours etc.

(4)   Pastural edema:-eg. :- transient edema of feet and ankles due to increased venous pressure.

(5)   Arteriolar dilation :- (a) heat           (b)neurohormonal dysregulation.

 

 

 

 

 

 

 

 

 

 

(2)Decreased colloid plasma osomotic pressure:-

·         Plasma osmotic pressure maximum used by total amount of plasma protein .

·         Plasma protein tends to draw fluid into the vessels normally.

·         Reduced total plasma protein level> 5g/dl (less then 5g/dl) hypoproteinemia , means hypoalbuminemia.

·         Reduced plasma ptn caused decreased colloid plasma osmotic pressure.

·         Plasma ptn.:- plasma protein are responsible for creating the osmotic pressure inside the plasma that tense to drowfluid , from outside of the blood vessels towards the blood vessels and when ever reduced production of plasma ptn. That will there imbalance b/w the osmotic pressure & capillary hydrostatic pressure and caused result edema.

·          Reduced plasma osmotic pressure have caused.

(1)   decreased production of plasma protein.

Glomerulopathies → Nephrotic syndrome

Gastroentropathies

(2) Liver cirrhosis

(3) Mal nutrition.

(3)Lymphatic obstruction:-

* normally the interstitial fluid in the tissue space escapes by way of lymphatics.

* main function of lymphatic vessels

(a)Fluid balance:-Lymphatic system helps to maintain fluid balance . it return excess fluid and protein from the interstitial tissue space that can not be returned through blood vessels.

(b) Absorption:- most of the fat absorbed from the gastrointestinaltract are taken up in a part of the gut membrane in the small intestine that in specially adopted by the lymphatic system.

(c)Immune system:-   lymphatic system is defence the body against unwanted organism. So when ever impaired /dysfunction of lymphatic vessels then they will cause impaired removal of interstitial fluid by the lymphatic system . so if there in excess interstitial fluid leads to developmentof edema . this type of edema is called lymphoedema.

Some example of lymphoedema  :-

(1)   Removal of axillary lymph nodes-

·         Suppose with the pt diagnose with breast carcinoma then that patient under gone radical martectomy and axillary lymph nodes are affected site are also removed.

·         After removal of axillary lymph nodes patient have high chance of develop lymph odema in the superior extrimities of effected site.

(2)pressure from outside:-

* when the malignant cells are obstructs the lymph channels .

* Lymphatic obstruction can be also caused by compression from out site particularly on thoracic duct.

·         If tumour /mass cavity is present then mass compress to thoracic duct then that cause of obstruction of lymphnodes and results in edema.

·         Some time thoracic duct may rupture and that they release the content of lymph to various body cavity if lymph is release in pleural cavity that is called chylothorax and lymph is release in paritonial cavity is called chylousascites.

(3)Inflammation of the lymphatics:-

This type of inflammation seen in filoriasis (infection with wuchereria bancrofti) result in chronic lymphoedema of scrotum and legs is known as elephantiasis. This is non pitting edema.

(4)Milray’s disease or herediatory lymphoedema :-

*   It is due to abnormal development of lymphatic channels.

* thoracic duct is the largest lymphatic vessel of the lymphatic system.

Milray disease :- it is the condition that affects the normal function of the lymphatic system.

·         Lymphatic system produce & transport fluids & immune cells through out the body.

·         When impaired transport with accumulation of lymph fluid can cause swelling ( lymphoedema)