Edema
Edema | |
Skin: Pitting Edema; Gross, close-up of dorsum of hand with marked pitting edema. Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: oedema or œdema
Overview
Edema (American English), formerly known as dropsy or hydropsy, is the increase of interstitial fluid in any organ — swelling. Generally, the amount of interstitial fluid is in the balance of homeostasis. Increased secretion of fluid into the interstitium or impaired removal of this fluid may cause edema. Cutaneous edema is referred to as "pitting" when, after pressure is applied to a small area, the indentation persists after the release of the pressure.
Classification
Edema can be classified into pitting edema and non piting edema. Peripheral pitting edema is the more common type, resulting from water retention. It can be caused by systemic diseases, pregnancy in some women, either directly or as a result of heart failure, or local conditions such as varicose veins, thrombophlebitis, insect bites, and dermatitis. Non-pitting edema is observed when the indentation does not persist. It is associated with such conditions as lymphedema, lipedema, and myxedema.
Pathophysiology
Generation of interstitial fluid is regulated by the Starling equation of tissue fluid which states that it depends on the balance of osmotic pressure and of hydrostatic pressure which act in opposite directions across the semipermeable capillary walls. Consequently, anything that increases oncotic pressure outside blood vessels (for example inflammation), or reduces oncotic pressure in the blood (states of low plasma osmolality, for example cirrhosis) will cause edema. Increased hydrostatic pressure inside the blood vessel (for example in heart failure) will have the same effect. If the permeability of the capillary walls increases, more fluid will tend to escape out of the capillary, as can happen when there is inflammation.
Causes
- Abnormal removal of interstitial fluid is caused by obstruction of the lymphatic system, for example due to pressure from a cancer or enlarged lymph nodes, destruction of lymph vessels by radiotherapy, or infiltration of the lymphatics by infection such as elephantiasis. People with edema may also present with a grey discoloration of the nail beds.
Causes by Organ System
Cardiovascular | No underlying causes |
Chemical/Poisoning | No underlying causes |
Dental | No underlying causes |
Dermatologic | No underlying causes |
Drug Side Effect | Aldesleukin, Alitretinoin, Apomorphine hydrochloride, Azficel-T, Bicalutamide, Chlordiazepoxide, Cidofovir, Conjugated estrogens, Cefaclor, Cetrorelix, Crizotinib, Desmopressin, Desogestrel and Ethinyl Estradiol, Dexamethasone, diclofenac (patch), Docetaxel, Doxercalciferol,
Estramustine, Ethynodiol diacetate and ethinyl estradiol, Felbamate, Flurbiprofen, Gallium nitrate, Hydrocortisone, Hydroxyprogesterone caproate, Lenalidomide, Lidocaine (cream), Lidocaine (ointment), Mefenamic acid, miltefosine, Nabilone, Niacin, Nilutamide, Oxandrolone, Oxaprozin, Pegaspargase, Pergolide, Penciclovir,Prednisolone, Prednisone, Sargramostim, Siltuximab, Sinecatechins, Streptozocin, Sodium phenylbutyrate, Terconazole, Tiagabine, Tolmetin, Von Willebrand factor |
Ear Nose Throat | No underlying causes |
Endocrine | No underlying causes |
Environmental | No underlying causes |
Gastroenterologic | No underlying causes |
Genetic | No underlying causes |
Hematologic | No underlying causes |
Iatrogenic | No underlying causes |
Infectious Disease | No underlying causes |
Musculoskeletal/Orthopedic | No underlying causes |
Neurologic | No underlying causes |
Nutritional/Metabolic | No underlying causes |
Obstetric/Gynecologic | No underlying causes |
Oncologic | No underlying causes |
Ophthalmologic | No underlying causes |
Overdose/Toxicity | No underlying causes |
Psychiatric | No underlying causes |
Pulmonary | No underlying causes |
Renal/Electrolyte | No underlying causes |
Rheumatology/Immunology/Allergy | No underlying causes |
Sexual | No underlying causes |
Trauma | No underlying causes |
Urologic | No underlying causes |
Miscellaneous | No underlying causes |
Causes in Alphabetical Order
Organ-Specific Edema
Edema of specific organs (cerebral edema, pulmonary edema, macular edema, pedal edema) may also occur, each with different specific causes to peripheral edema, but all based on the same principles. Ascites is effectively edema within the peritoneal cavity, as pleural effusions are effectively edema in the pleural cavity. Causes of edema which are generalized to the whole body can cause edema in multiple organs and peripherally. For example, severe heart failure can cause peripheral edema, pulmonary edema, pleural effusions and ascites.
Common and usually harmless appearances of cutaneous edema are observed with mosquito bites and skin contact with certain plants (urticaria).
Edema may be found in the eyes after corrective surgery or procedures of that nature.
References
External links
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