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Variant of edema.


See edema.


An accumulation of an excessive amount of watery fluid in cells, tissues, or serous cavities.
Synonym(s): oedema.
[G. oidēma, a swelling]


Excessive accumulation of fluid, mainly water, in the tissue spaces of the body. Oedema may be local, as at the site of an injury, or general. It often affects specific organs, such as the brain or the lungs. It may be caused by injury, allergy, starvation, HEART FAILURE, kidney failure or disease-especially the NEPHROTIC SYNDROME, liver disease-CIRRHOSIS, hormonal changes in the menstrual cycle, varicose veins or poisoning. General oedema is often treated with DIURETIC drugs.




a swelling of tissues caused by the capilliary blood vessels passing out water into the surrounding tissues, and so increasing the intercellular fluid content.


accumulation of excess tissue fluid in distal limb tissues associated with e.g. local inflammation/infection, abnormal lymphatic drainage, abdominal mass or cardiac/lung/renal dysfunction (Table 1)
  • anaphylactic oedema generalized swelling of facial skin and mucous membranes with associated difficulty in breathing and profound drop in blood pressure; characteristic of anaphylaxis (see anaphylaxis)

  • cardiac oedema peripheral oedema due to congestive heart failure

  • joint oedema oedema of joint soft tissues, due to joint (e.g. rheumatoid or osteoarthritis) or ligamentous inflammation (e.g. mechanical trauma, joint strain/sprain)

  • non-pitting oedema indurated and firm oedematous lower-limb tissues; indicative of long-standing oedema and fibrosis, e.g. in long-term venous incompetence

  • peripheral oedema oedema of distal (foot and limb) tissues secondary to e.g. cardiac, pulmonary or renal dysfunction, venous dysfunction, abdominal mass or hypertension

  • pitting oedema relatively soft, tissue oedema affecting both feet and lower legs or unilateral swelling of a limb with incompetent venous return; characterized by retention of the depression caused by fingertip pressure

  • pulmonary oedema lung oedema due to heart valve dysfunction

Table 1: Presentations of oedema in the lower limb
Oedema typeCause
UnilateralWithin the limb
Local, e.g. as the result of local trauma, inflammation or infection
Regional, e.g. as the result of proximal limb trauma, inflammation, infection or venous compromise
BilateralSystemic disease (e.g. heart disease, renal dysfunction, abdominal mass, hypertension, lung dysfunction)
PittingSystemic disease (e.g. heart disease; hypertension; venous compromise)
Indurated/non-pittingLong-standing oedema (e.g. marked venous compromise; subsequent to deep-vein thrombosis)


The presence of an excessive amount of fluid in or around cells, tissues or serous cavities of the body. In the eye oedema can occur in the cornea, the conjunctiva, the uvea, the retina, the choroid, and the ciliary body. Corneal oedema usually accompanies eye diseases, or contact lens wear with low oxygen transmissibility. Corneal oedema is easily seen with a slit-lamp using retroillumination or sclerotic scatter illumination. Quantitatively, it can be assessed with the addition of a pachometer that measures corneal swelling. Beyond about 4% swelling, there appear striae (wispy greyish-white lines usually vertical) in the stroma. Beyond about 8% swelling, there appear folds (dark lines) believed to represent physical buckling of the posterior corneal layers. Corneal swelling of 15% or greater, which indicates a gross separation of the collagen fibres of the stroma, results in a hazy or cloudy appearance of the cornea. There is a physiological oedema occurring during sleep in every human cornea amounting to an increase in thickness of about 4%. Corneal oedema gives rise to the appearance of haloes around lights, photophobia, spectacle blur, losses in corneal transparency and sometimes stinging. Management depends on the cause and tissue involved. If due to contact lenses, refitting with daily wear lenses of higher oxygen transmissibility and reducing wearing time usually solves the problem. Note: also spelt edema. See endothelial blebs; central corneal clouding; hypoxia; silicone hydrogel lens; oxygen permeability; critical oxygen requirement; pachometer; overwear syndrome.


1. Excessive fluid in cells or intercellular tissues.
2. At the gross level, used to describe physical sign commonly likened to swelling or increased girth that often accompanies fluid accumulation in a limb.
[G. oidēma, a swelling]


see edema.

Patient discussion about oedema

Q. does mosquito bites considered as an edema a bet with a friend- please help solve an issue an help me win a new I pod :)

A. (don't take the mini i-pod, it sucks). it's true-the mosquito has a number of proteins and materials in his saliva that works as anticoagulants and vasodilators (blood vessel broadening). these causes the bite area to start an immune reaction and one of the consequences is an edema-"an increase of interstitial fluid in any organ", that means fluids are exiting blood system. in this case- not too much...

Q. what is "pulmonary edema" and what are the risks? my Dr. told me I'm in a risk group for pulmonary edema, he tried to explain what it is but i didn't understand fully...if someone may give me a brief explanation- I'll appreciate it!

A. pulmonary edema occurs when, lets say, your heart left ventricle stops working properly and your right ventricle works fine. that means your lungs getting lets presume- 1 liter of blood -but your left ventricle can pump out of it only 990 ml. that means you have high blood pressure in your lungs and fluid comes out of blood vessels and fills your lungs, making it harder and harder breathing.

More discussions about oedema