Edema
Edema | |
---|---|
Other names | Oedema, œdema, fluid retention, water retention, dropsy, hydropsy |
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"Pitting" edema | |
Pronunciation | |
Specialty | Cardiology,nephrology |
Symptoms | Skin which feels tight, area may feel heavy[1] |
Usual onset | Sudden or gradual[2] |
Types | Generalized, localized[2] |
Causes | Venous insufficiency,heart failure,kidney problems,low protein levels,liver problems,deep vein thrombosis,lymphedema[1][2] |
Diagnostic method | Based on aphysical exam[3] |
Treatment | Based on cause[2] |
Edema(American English), also spelledoedema(British English), and also known asfluid retention,dropsyandhydropsy,is the build-up of fluid in the body'stissue,[1]a type of swelling.[4]Most commonly, the legs or arms are affected.[1]Symptoms may include skin that feels tight, the area feeling heavy, and joint stiffness.[1]Other symptoms depend on the underlying cause.[2]
Causes may includevenous insufficiency,heart failure,kidney problems,low protein levels,liver problems,deep vein thrombosis,infections,angioedema,certain medications, andlymphedema.[1][2]It may also occur in immobile patients (stroke, spinal cord injury, aging), or with temporary immobility such as prolonged sitting or standing, and duringmenstruationorpregnancy.[1]The condition is more concerning if it starts suddenly, or pain or shortness of breath is present.[2]
Treatment depends on the underlying cause.[2]If the underlying mechanism involvessodium retention,decreased salt intake and adiureticmay be used.[2]Elevating the legs andsupport stockingsmay be useful for edema of the legs.[3]Older people are more commonly affected.[3]The word is from theAncient Greekοἴδημαoídēmameaning 'swelling'.[5]
Signs and symptoms
[edit]Specific area
[edit]An edema will occur in specific organs as part of inflammations,tendinitisorpancreatitis,for instance. Certain organs develop edema through tissue specific mechanisms. Examples of edema in specific organs:
- Peripheral edema( “dependent” edema of legs) is extracellular fluid accumulation in the lower extremities caused by the effects of gravity, and occurs when fluid pools in the lower parts of the body, including the feet, legs, or hands. This often occurs in immobile patients, such as paraplegics or quadriplegics, pregnant women, or in otherwise healthy people due tohypervolemiaor maintaining a standing or seated posture for an extended period of time. It can occur due to diminished venous return of blood to the heart due to congestive heart failure or pulmonary hypertension. It can also occur in patients with increased hydrostatic venous pressure or decreased oncotic venous pressure, due to obstruction of lymphatic or venous vessels draining the lower extremity. Certain drugs (for example, amlodipine) can cause pedal edema.
- Cerebral edemais extracellular fluid accumulation in the brain.[1]It can occur in toxic or abnormal metabolic states and conditions such as systemic lupus or reduced oxygen at high altitudes. It causes drowsiness or loss of consciousness, leading tobrain herniationand death.
- Pulmonary edemaoccurs when the pressure in blood vessels in the lung is raised because of obstruction to the removal of blood via the pulmonary veins. This is usually due to failure of the left ventricle of the heart. It can also occur in altitude sickness or on inhalation of toxic chemicals. Pulmonary edema produces shortness of breath.Pleural effusionsmay occur when fluid also accumulates in thepleuralcavity.
- Edema may also be found in the cornea of the eye withglaucoma,severeconjunctivitis,keratitis,or after surgery. Affected people may perceive coloured haloes around bright lights.
- Edema surrounding the eyes is calledperiorbital edema(puffy eyes). The periorbital tissues are most noticeably swollen immediately after waking, perhaps as a result of the gravitational redistribution of fluid in the horizontal position.
- Common appearances ofcutaneousedema are observed withmosquitobites,spiderbites, bee stings (wheal and flare), and skin contact with certain plants such aspoison ivyorwestern poison oak,[6]the latter of which are termedcontact dermatitis.
- Another cutaneous form of edema ismyxedema,which is caused by increased deposition ofconnective tissue.In myxedema (and a variety of other rarer conditions) edema is caused by an increased tendency of the tissue to hold water within its extracellular space. In myxedema, this is due to an increase in hydrophilic carbohydrate-rich molecules (perhaps mostlyhyaluronin) deposited in the tissue matrix. Edema forms more easily in dependent areas in the elderly (sitting in chairs at home or on aeroplanes) and this is not well understood. Estrogens alter body weight in part through changes in tissue water content. There may be a variety of poorly understood situations in which transfer of water from tissue matrix to lymphatics is impaired because of changes in the hydrophilicity of the tissue or failure of the 'wicking' function of terminal lymphatic capillaries.
- Myoedema is localized mounding of muscle tissue due to percussive pressure, such as flicking the relaxed muscle with the forefinger and thumb. It produces a mound, visible, firm and non-tender at the point of tactile stimulus approximately 1-2 seconds after stimulus, subsiding back to normal after 5-10 seconds. It is a sign in hypothyroid myopathy, such asHoffmann syndrome.[7]
- Inlymphedema,abnormal removal of interstitial fluid is caused by failure of thelymphatic system.This may be due to obstruction from, for example, pressure from acanceror enlargedlymph nodes,destruction of lymph vessels byradiotherapy,or infiltration of the lymphatics by infection (such aselephantiasis). It is most commonly due to a failure of the pumping action of muscles due to immobility, most strikingly in conditions such as multiple sclerosis, or paraplegia. It has been suggested that the edema that occurs in some people following use of aspirin-like cyclo-oxygenase inhibitors such as ibuprofen or indomethacin may be due to inhibition of lymph heart action.
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Foot two weeks post-surgery.
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Thedistal phalanxof the right finger exhibits edema due toacute paronychia.
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Severe edema in the legs and feet.
Generalized
[edit]A rise inhydrostatic pressureoccurs in cardiac failure. A fall in osmotic pressure occurs innephrotic syndromeandliver failure.[8]
Causes of edema that are generalized to the whole body can cause edema in multiple organs and peripherally. For example, severe heart failure can causepulmonary edema,pleural effusions,ascitesandperipheral edema.Such severe systemic edema is calledanasarca.In rare cases, aparvovirus B19infection may cause generalized edemas.[9]
Although a low plasmaoncotic pressureis widely cited for the edema of nephrotic syndrome, most physicians note that the edema may occur before there is any significant protein in the urine (proteinuria) or fall in plasma protein level. Most forms of nephrotic syndrome are due to biochemical and structural changes in the basement membrane of capillaries in the kidney glomeruli, and these changes occur, if to a lesser degree, in the vessels of most other tissues of the body. Thus the resulting increase in permeability that leads to protein in the urine can explain the edema if all other vessels are more permeable as well.[10]
As well as the previously mentioned conditions, edemas often occur during the late stages of pregnancy in some women. This is more common with those of a history of pulmonary problems or poor circulation also being intensified if arthritis is already present in that particular woman. Women who already have arthritic problems most often have to seek medical help for pain caused from over-reactive swelling. Edemas that occur during pregnancy are usually found in the lower part of the leg, usually from the calf down.
Hydrops fetalisis a condition in a baby characterized by an accumulation of fluid in at least two body compartments.
Cause
[edit]Heart
[edit]The pumping force of theheartshould help to keep a normal pressure within theblood vessels.But if the heart begins to fail (a condition known ascongestive heart failure) the pressure changes can cause very severe water retention. In this condition water retention is mostly visible in thelegs,feet andankles,but water also collects in thelungs,where it causes a chroniccough.This condition is usually treated withdiuretics;otherwise, the water retention may cause breathing problems and additional stress on the heart.[11]
Kidneys
[edit]Another cause of severe water retention iskidney failure,where thekidneysare no longer able to filter fluid out of thebloodand turn it intourine.Kidney diseaseoften starts withinflammation,for instance in the case of diseases such asnephrotic syndromeorlupus.This type of water retention is usually visible in the form of swollenlegsandankles.[12]
Liver
[edit]Cirrhosis(scarring) of the liver is a common cause of edema in the legs and abdominal cavity.[13]
Veins
[edit]Phlebetic lymphedema (or phlebolymphedema) is seen in untreatedchronic venous insufficiencyand is the most common type of edema (approx. 90%).[14]It is a combination venous/lymphatic disorder that originates in defective "leaky" veins that allows the blood to back flow (venous reflux), slowing the return of the blood to the heart (venous stasis). The venous pressure in the legs changes dramatically while standing compared to lying down. How much pressure there is depends on the person's height, in the average adult person, it is 8 mm Hg while lying down and 100 mm Hg while standing.[15]
In venous insufficiency, venous stasis results in abnormally high venous pressure (venous hypertension) and greater permeability of blood capillaries (capillary hyperpermeability), to drain the blood through the lymphatic system. The lymphatic system slowly removes excess fluid and proteins from the veins in the lower legs towards the upper body; however, as it is not as efficient as an unimpaired circulatory system, swelling (edema) is visible, particularly in the ankles and lower leg. The chronic increased fluid in the lymphatic system and capillary hyperpermeability causes an inflammatory response which leads to tissue fibrosis of both veins and lymphatic system, opening of arteriovenous shunts, all of which then worsens the condition in a vicious cycle.[14][15]
Others
[edit]Swollenlegs,feet andanklesare common in latepregnancy.The problem is partly caused by the weight of theuteruson the majorveinsof thepelvis.It usually clears up after delivery of the baby, and is mostly not a cause for concern,[16]though it should always be reported to a doctor.
Lack of exercise is another common cause of water retention in the legs. Exercise helps the legveinswork againstgravityto returnbloodto theheart.Ifbloodtravels too slowly and starts to pool in thelegveins,the pressure can force too much fluid out of thelegcapillariesinto the tissue spaces. Thecapillariesmay break, leaving small blood marks under theskin.Theveinsthemselves can become swollen, painful and distorted – a condition known asvaricose veins.[17]Muscleaction is needed not only to keepbloodflowing through theveinsbut also to stimulate thelymphatic systemto fulfil its "overflow" function. Long-haulflights,lengthybed-rest,immobility caused bydisabilityand so on, are all potential causes of water retention. Even very small exercises such as rotatinganklesand wigglingtoescan help to reduce it.[18]
Certainmedicationsare prone to causing water retention. These includeestrogens,thereby including drugs forhormone replacement therapyor thecombined oral contraceptive pill,[19]as well asnon-steroidal anti-inflammatory drugsandbeta-blockers.[20]
Premenstrual water retention,causingbloatingandbreast tenderness,is common.[21][22][23]
Mechanism
[edit]Six factors can contribute to the formation of edema:[24]
- increasedhydrostatic pressure;
- reduced colloidal oroncotic pressurewithin blood vessels;
- increased tissue colloidal or oncotic pressure;
- increased blood vessel wall permeability (such asinflammation);
- obstruction of fluid clearance in thelymphatic system;
- changes in the water-retaining properties of the tissues themselves. Raised hydrostatic pressure often reflects retention of water and sodium by the kidneys.[25]
Generation of interstitial fluid is regulated by the forces of theStarling equation.[26]Hydrostatic pressure within blood vessels tends to cause water to filter out into the tissue. This leads to a difference in protein concentration between blood plasma and tissue. As a result, the colloidal oroncotic pressureof the higher level of protein in the plasma tends to draw water back into the blood vessels from the tissue. Starling's equation states that the rate of leakage of fluid is determined by the difference between the two forces and also by the permeability of the vessel wall to water, which determines the rate of flow for a given force imbalance. Most water leakage occurs in capillaries or post capillaryvenules,which have asemi-permeable membranewall that allows water to pass more freely than protein. (The protein is said to be reflected and the efficiency of reflection is given by a reflection constant of up to 1.) If the gaps between the cells of the vessel wall open up then permeability to water is increased first, but as the gaps increase in size permeability to protein also increases with a fall in reflection coefficient.[27]
Changes in the variables in Starling's equation can contribute to the formation of edemas either by an increase in hydrostatic pressure within the blood vessel, a decrease in the oncotic pressure within the blood vessel or an increase in vessel wall permeability. The latter has two effects. It allows water to flow more freely and it reduces the colloidal or oncotic pressure difference by allowing protein to leave the vessel more easily.[citation needed]
Another set of vessels known as thelymphatic systemacts like an "overflow" and can return much excess fluid to thebloodstream.But even thelymphatic systemcan be overwhelmed, and if there is simply too much fluid, or if thelymphatic systemis congested, then the fluid will remain in the tissues, causing swellings inlegs,ankles,feet,abdomenor any other part of the body.[28]
Molecular biology
[edit]The excessiveextracellular fluid(interstitial fluid) in edemas is to a substantial degree caused by an increasedpermeabilityof the smallest blood vessels (capillaries). This permeability is modulated by numerous biochemical chain reactions and can therefore be unbalenced by many influences.[29]
Involved in these processes are, among others, thetransmembrane proteinsoccludin,claudins,tight junction protein ZO-1,cadherins,cateninsandactinin,which are directed by intracellular signal chains, in particular in connection with theenzymeprotein kinase C.[30]
Diagnosis
[edit]Grade | Definition |
---|---|
Absent | Absent |
+ | Mild: Both feet / ankles |
++ | Moderate: Both feet, plus lower legs, hands or lower arms |
+++ | Severe: Generalised bilateral pitting edema, including both feet, legs, arms and face |
Edema may be described aspitting edema,ornon-pitting edema.[32]Pitting edema is when, after pressure is applied to a small area, the indentation persists after the release of the pressure.Peripheralpitting edema, as shown in the illustration, 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 ofheart failure,or local conditions such asvaricose veins,thrombophlebitis,insect bites, anddermatitis.[33]
Non-pitting edema is observed when the indentation does not persist. It is associated with such conditions aslymphedema,lipedema,andmyxedema.
Edema caused by malnutrition defineskwashiorkor,an acute form of childhood protein-energy malnutrition characterized by edema, irritability, anorexia,ulcerating dermatoses,and an enlarged liver with fatty infiltrates.
Treatment
[edit]When possible, treatment involves resolving the underlying cause. Many cases ofheartorkidneydisease are treated withdiuretics.[11]
Treatment may also involve positioning the affected body parts to improve drainage. For example, swelling in feet or ankles may be reduced by having the person lie down in bed or sit with the feet propped up on cushions.Intermittent pneumatic compressioncan be used to pressurize tissue in a limb, forcing fluids—both blood andlymph—to flow out of the compressed area.[34]
References
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- ^Hogan CM (2008). Strömberg N (ed.)."Western poison-oak: Toxicodendron diversilobum".GlobalTwitcher.Archived fromthe originalon July 21, 2009.
- ^Vignesh G, Balachandran K, Kamalanathan S, Hamide A (2013)."Myoedema: A clinical pointer to hypothyroid myopathy".Indian Journal of Endocrinology and Metabolism.17(2): 352.doi:10.4103/2230-8210.109672.ISSN2230-8210.PMC3683223.PMID23776921.
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- ^Wiggli B, Imhof E, Meier CA, Laifer G (2013). "Water, water, everywhere. Acute parvovirus B19 infection".Lancet.381(9868): 776.doi:10.1016/S0140-6736(12)61894-7.PMID23472922.S2CID19300719.
- ^Palmer BF, Alpern RJ (1997). "Pathogenesis of edema formation in the nephrotic syndrome".Kidney Int. Suppl.59:S21–7.PMID9185099.
- ^abCasu G, Merella P (July 2015)."Diuretic Therapy in Heart Failure – Current Approaches".European Cardiology Review.10(1): 42–47.doi:10.15420/ecr.2015.10.01.42.ISSN1758-3756.PMC6159465.PMID30310422.
- ^"Edema - Symptoms and causes".Mayo Clinic.Retrieved2022-07-19.
- ^"Edema - Symptoms and causes".Mayo Clinic.Retrieved2022-12-23.
- ^abPublishing L, Guiboles (2009-11-24)."The causes of edema in chronic venous insufficiency".Servier - Phlebolymphology.Retrieved2023-09-01.
- ^abFarrow W (2010)."Phlebolymphedema-a common underdiagnosed and undertreated problem in the wound care clinic".The Journal of the American College of Certified Wound Specialists.2(1): 14–23.doi:10.1016/j.jcws.2010.04.004.ISSN1876-4983.PMC3601853.PMID24527138.
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- ^Timby BK, Smith NE (2006).Introductory Medical-Surgical Nursing(9th ed.). Philadelphia: Lippincott Williams & Wilkins. p.488.ISBN978-0-78178-032-2.
- ^Zuther JE (2005).Lymphedema Management: The Comprehensive Guide for Practitioners(1st ed.). New York:Thieme Medical Publishers.p. 222.ISBN978-1-58890-284-9.
- ^"Estrogens (Conjugated/Equine)".The Merck Manual.Archived fromthe originalon 2 December 2007.Retrieved9 August2017.
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- ^Charlotte Pooler (1 October 2009).Porth Pathophysiology: Concepts of Altered Health States.Lippincott Williams & Wilkins. pp. 1075, 1107.ISBN978-1-60547-781-7.
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- ^Kumar, Abbas, Fausto (1999).Pathologic Basis of Disease(7th ed.). Elsevier Saunders. p. 122.ISBN0-7216-0187-1.
- ^Boron WF, Boulpaep EL (2012). "2e".Medical Physiology: A Cellular and Molecular Approach.Philadelphia: Saunders/Elsevier.
- ^Dvorak HF (April 2010)."Vascular permeability to plasma, plasma proteins, and cells: an update".Current Opinion in Hematology.17(3): 225–229.doi:10.1097/MOH.0b013e3283386638.PMC2878124.PMID20375889.
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- ^Cai A, Chatziantoniou C, Calmont A (2021)."Vascular Permeability: Regulation Pathways and Role in Kidney Diseases".Nephron.145(3): 297–310.doi:10.1159/000514314.PMID33744890.
{{cite journal}}
:CS1 maint: multiple names: authors list (link) - ^Doucet A, Favre G, Deschênes G (2007)."Molecular mechanism of edema formation in nephrotic syndrome: therapeutic implications".Pediatr Nephrol.22(12): 1983–90.doi:10.1007/s00467-007-0521-3.PMC2064946.PMID17554565.
{{cite journal}}
:CS1 maint: multiple names: authors list (link) - ^Nutrition in Emergencies > Measuring œdemaArchived2017-02-18 at theWayback Machine.Erin Boyd, reviewed by Diane Holland, Nutrition in Emergencies Unit,UNICEF.Retrieved Nov 2012
- ^Booth S."Pitting Edema".WebMD.Retrieved1 January2023.
- ^Causes and signs of edema.Institute for Quality and Efficiency in Health Care (IQWiG). 30 December 2016.Retrieved26 July2022.
- ^Zaleska M, Olszewski WL, Cakala M, Cwikla J, Budlewski T (June 2015)."Intermittent Pneumatic Compression Enhances Formation of Edema Tissue Fluid Channels in Lymphedema of Lower Limbs".Lymphatic Research and Biology.13(2): 146–153.doi:10.1089/lrb.2014.0010.PMC4492553.PMID25748341.
External links
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