cerebral edema

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the accumulation of excess fluid in a fluid compartment. Formerly called dropsy and hydrops. adj., adj edem´atous. This accumulation can occur in the cells (cellular edema), in the intercellular spaces within tissues (interstitial edema), or in potential spaces within the body. Edema may also be classified by location, such as pulmonary edema or brain edema; types found in certain locations have specific names, such as ascites (peritoneal cavity), hydrothorax (pleural cavity), or hydropericardium (pericardial sac). Massive generalized edema is called anasarca. Classification by location does not indicate whether the edema is cellular or interstitial or occupies a potential space (for example, brain edema may be either cellular or interstitial). Edema can be caused by a variety of factors, including conditions that affect osmotic pressure, such as hypotonic fluid overload, which allows the movement of water into the intracellular space, or hypoproteinemia, which decreases the concentration of plasma proteins and permits the passage of fluid out of the blood vessels into the tissue spaces. Other factors include poor lymphatic drainage; conditions that cause increased capillary pressure, such as excessive retention of salt and water and heart failure; and conditions that increase capillary permeability, such as inflammation.
Edema formation. With trauma, increased capillary permeability and dilation cause leaking into tissue space. Initially clear, exudate in the tissue space becomes more viscous with an increase in plasma protein. From Copstead and Banasik, 2000.
alveolar edema pulmonary edema in the alveoli, usually with hypoxemia and dyspnea.
brain edema cerebral edema.
cardiac edema a manifestation of congestive heart failure, due to increased venous and capillary pressures and often associated with renal sodium retention.
cellular edema edema caused by the entry of water into the cells, causing them to swell. This may occur because of decreased osmolality of the fluid surrounding the cells, as in hypotonic fluid overload, or increased osmolality of the intracellular fluid, as in conditions that decrease the activity of the sodium pump of the cell membrane, allowing the concentration of sodium ions within the cell to increase.
cerebral edema swelling of the brain caused by the accumulation of fluid in the brain substance. It may result from head injury, stroke, infection, hypoxia, brain tumors, obstructive hydrocephalus, and lead encephalopathy; it may also be caused by disturbances in fluid and electrolyte balance that accompany hemodialysis and diabetic ketoacidosis. The most common type is vasogenic edema, which may result from increased capillary pressure or from increased capillary permeability caused by trauma to the capillary walls. Cellular edema may occur in ischemia or hypoxia of the brain. Because the brain is enclosed in the solid vault of the skull, edema compresses the blood vessels, decreasing the blood flow and causing ischemia and hypoxia, which in turn result in further edema. Unless measures are taken to reverse the edema, destruction of brain tissue and death will result.
dependent edema edema of the lowermost parts of the body relative to the heart; it is affected by gravity and position, so that the lower limbs are affected if the individual is standing, but the buttocks are affected if the individual is supine.
generalized edema edema that is caused by poor venous return; it is not localized by the effects of gravity, in contrast to dependent edema.
interstitial edema
1. edema caused by the accumulation of fluid in the extracellular spaces of a tissue.
2. pulmonary edema in the interstitial tissues; there is dyspnea but no hypoxemia.
edema neonato´rum sclerema neonatorum.
nonpitting edema edema in which pressure does not leave a depression in the tissues, such as in cellular edema. See also pitting edema.
pedal edema swelling of the feet and ankles.
peripheral edema edema affecting the extremities; seen in heart disease, Crohn's disease, and amyloidosis.
pitting edema edema in which external pressure leaves a persistent depression in the tissues (see pitting); it occurs because the pressure pushes the excess fluid out of the intercellular spaces in the tissue. See also nonpitting edema.
pulmonary edema diffuse extravascular accumulation of fluid in the tissues and air spaces of the lung due to changes in hydrostatic forces in the capillaries or to increased capillary permeability. It is most often symptomatic of left ventricular heart failure, but can also be a complication of mitral stenosis, aortic stenosis, altitude sickness, acute hypertension, volume overload during intravenous therapy, or reduced serum oncotic pressure, as in patients who have nephrosis, cirrhosis, or hypoalbuminemia.

During the initial stage of pulmonary edema, patients may complain of restlessness and anxiety and the feeling that they are getting a common cold. Other signs include a persistent cough, slight dyspnea, and intolerance to exercise. On auscultation, rales can be heard over the dependent portion of the lung. As fluid continues to fill the pulmonary interstitial spaces the dyspnea becomes more acute, respirations increase in rate, and there is audible wheezing. The cough becomes productive of frothy sputum tinged with blood, giving it a pinkish hue. Eventually, if the condition persists, the patient becomes less responsive to stimuli as levels of consciousness decrease. Ventricular arrhythmias develop and breath sounds diminish. In some patients these phases are telescoped as the pulmonary edema develops rapidly and the final stages of respiratory insufficiency are evident in a very short period of time.

Treatment is aimed at enhancing gas exchange, reducing fluid overload, and strengthening and slowing the heart beat. To accomplish these goals the patient is often given oxygen by mask or through mechanically assisted ventilation. Drug therapy includes diuretics to remove excess alveolar fluid and morphine to relieve anxiety and reduce the effort of breathing. Administration of other medications depends on the cause of the edema, as well as what other problems the patient may be having.
vasogenic edema that characterized by increased permeability of capillary endothelial cells; the most common form of cerebral edema.

ce·re·bral e·de·ma

brain swelling due to increased volume of the extravascular compartment from the uptake of water in the neuropil and white matter.
See also: brain swelling.
Synonym(s): brain edema

cerebral edema

Etymology: L, cerebrum + Gk, oidema, swelling
an accumulation of fluid in the brain tissues. Causes include infection, tumor, trauma, or exposure to certain toxins. Because the skull cannot expand to accommodate the fluid pressure, brain tissues are compressed. Early symptoms are changes in level of consciousness: sluggishness, then dilation of one or both pupils, and a gradual loss of consciousness. Cerebral edema can be fatal.

cerebral edema

Medtalk Brain swelling Neurology Swelling of cerebral interstitial tissue Etiology CE may be seen in bacterial meningitis in children, after trauma and in alcoholics Clinical Absent oculocephalic response, fixed eye deviation, coma Management IV mannitol, decompression.

ce·re·bral e·de·ma

(ser'ĕ-brăl ĕ-dē'mă)
Brain swelling due to increased volume of the extravascular compartment from the uptake of water in the neuropile and white matter.
See also: brain swelling


(e-de'ma) (-de'mat-a) plural.edemasplural.edemata [Gr. oidema, swelling, tumor]
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EDEMA: Edematous arm caused by subclavian vein stenosis
A local or generalized condition in which body tissues contain an excessive amount of tissue fluid in the interstitial spaces. Synonym: hydrops See: anasarca; ascites; dropsy; hydrothorax; pericardial effusion See: illustrationedematous (e-de'mat-us), adjective


Edema may result from increased permeability of the capillary walls; increased capillary pressure due to venous obstruction or heart failure; lymphatic obstruction; disturbances in renal function; reduction of plasma proteins; inflammatory conditions; fluid and electrolyte disturbances, esp. those causing sodium retention; malnutrition; starvation; or chemical substances such as bacterial toxins, venoms, caustics, and histamine. Diagnostic studies ( thorough history, physical examination, urinalysis, serum chemistries and liver functions, thyroid function, and chest x-ray) help determine the cause and guide treatment.


Bed rest helps relieve lower extremity edema. Sitting with the feet and legs elevated may also reduce edema in the lower extremities. Dietary salt should be restricted to less than 2 g/day. Fluid intake may be restricted to about 1500 ml in 24 hr. This prescription may be relaxed when free diuresis has been attained. Diuretics relieve swelling when renal function is good and when any underlying abnormality of cardiac function, capillary pressure, or salt retention is being corrected simultaneously. Any effective diuretic may be used. Diuretics are contraindicated in preeclampsia and when serum potassium levels are very low (< 3.0 mEq/dl). They may be ineffective in edema associated with advanced renal insufficiency. The diet in edema should be adequate in protein, high in calories, and rich in vitamins. Patients with significant edema should weigh themselves daily to gauge fluid loss or retention.

Patient care

Edema is documented according to type (pitting, nonpitting, or brawny), extent, location, symmetry, and degree of pitting. Areas over bony prominences are palpated for edema by pressing with the fingertip for 5 sec, then releasing. Normally, the tissue should immediately rebound to its original contour; therefore the depth of indentation is measured and recorded. The patient is questioned about increased tightness of rings, shoes, waistlines of garments, and belts. Periorbital edema is assessed; abdominal girth and ankle circumference are measured; and the patient's weight and fluid intake and output are monitored. Fragile edematous tissues are protected from damage by careful handling and positioning and by providing and teaching about special skin care. Edematous extremities are mobilized and elevated to promote venous return, and lung sounds auscultated for evidence of increasing pulmonary congestion. Prescribed therapies, including sodium restriction, diuretics, ACE inhibitors, protein replacement, and elastic stockings are provided, and the patient is instructed in their use.

angioneurotic edema


Berlin edema

Commotio retinae.

brain edema

Swelling of the brain. It may be caused by increased permeability of brain capillary endothelial cells, focal strokes, swelling of brain cells associated with hypoxia or water intoxication, trauma to the skull, or interstitial edema due to obstructive hydrocephalus.
Synonym: brain swelling; cerebral edema

edema bullosum vesicae

Edema affecting the bladder.

cardiac edema

Edema due to congestive heart failure. It is most apparent in the dependent portion of the body and/or the lungs.

cerebral edema

Brain edema.

dependent edema

Edema of the lower extremities or, if the patient is lying down, of the sacrum.

diabetic macular edema

Swelling of the retina resulting from leakage of fluids from damaged blood vessels in the eye. It is a major cause of visual loss in diabetics, and is related to poor control of blood glucose.

edema of the glottis

Pathological edema in the tissues lining the vocal structures of the larynx. It may result from improper use of the voice, excessive use of tobacco or alcohol, chemical fumes, or viral, bacterial, or fungal infections. Clinically, the patient often presents with hoarseness or, in severe cases, with respiratory distress and stridor. See: epiglottitis


Initially, hoarseness and, later, complete aphonia characterize this condition. Other symptoms are extreme dyspnea, at first on inspiration only, but later also on expiration; stridor; and a barking cough when the epiglottis is involved.

high-altitude pulmonary edema

Abbreviation: HAPE
Pulmonary edema that may occur in aviators, mountain climbers, or anyone exposed to decreased atmospheric pressure.
See: hypoxia

inflammatory edema

Edema associated with inflammation. The cause is assumed to be damage to the capillary endothelium. It is usually nonpitting and localized, red, tender, and warm.

laryngeal edema

Edema of the larynx, usually resulting from allergic reaction and causing airway obstruction unless treated. Therapy consists of intravenous or intratracheal epinephrine, emergency tracheostomy, or both.

malignant edema

Rapid destruction of tissue by cutaneous or subcutaneous infections, such as anthrax or clostridial species.

negative pressure pulmonary edema

Pulmonary edema occurring in a patient with upper airway obstruction and negative intrapleural pressures, e.g., in a child with epiglottitis.

edema neonatorum

Edema in newborn, esp. premature, infants. This condition is usually transitory, involving the hands, face, feet, and genitalia, and rarely becomes generalized.
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PITTING EDEMA: Demonstration of pitting edema
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PITTING EDEMA: Demonstration of pitting edema

pitting edema

Evidence of fluid in soft tissues, esp. those of dependent body parts like the lower extremities. When pressed firmly with a finger, tissues that are swollen with extravascular fluid retain the shape of the depression produced by the finger. See: illustration

post-traumatic edema

Traumatic edema.

pretibial edema

Edema of the lower leg anterior to the shin (the tibia).

pulmonary edema

A potentially life-threatening edema in the interstitium and alveoli of the lungs. The collected fluid may block the exchange of oxygen and carbon dioxide and produce respiratory failure.


Fluid may seep out of the alveolar capillaries if these blood vessels are damaged and become excessively permeable to liquids (noncardiogenic pulmonary edema) or if hydrostatic pressures within blood vessels exceed the strength of the normal alveolar capillary wall (cardiogenic pulmonary edema). Cardiogenic pulmonary edema can result from any condition that compromises left ventricular function, causing elevations in pulmonary venous and capillary hydrostatic pressures (congestive heart failure), including myocardial infarction, ischemia, or myocardial stunning; severe valvular heart disease; arrhythmias; excessive intravenous fluid administration; and diastolic dysfunction.

Noncardiogenic pulmonary edema usually results from blood vessel injury, as happens in the adult respiratory distress syndrome (sepsis, shock, aspiration pneumonia, airway obstruction). Occasionally, protein-rich fluid floods the lungs from drug exposure (such as heroin overdose), hypoalbuminemia, high-altitude exposure (mountain sickness), fresh water aspiration in near drowning, hemorrhage in or around the brain, or other conditions. Pulmonary edema can occur as a chronic or acute condition.


Chronic symptoms include dyspnea or exertion, nocturnal dyspnea, orthopnea, and cough. When pulmonary edema develops rapidly, patients experience a rapid onset of shortness of breath and suffocation and often demonstrate labored, noisy breathing; cough producing frothy, bloody sputum; gasping; anxiety; palpitations; and altered mental status caused by inadequate oxygenation. Signs of the condition include a rapid respiratory rate, heaving of the chest and abdomen, intercostal muscle retractions, diffuse crackles on lung exam, and, often, cold, clammy skin with diaphoresis and cyanosis. Tachycardia, jugular vein distension, and a diastolic (S3) gallop occur. As cardiac output decreases, the pulse becomes thready, and blood pressure falls. Pulmonary artery catheterization helps identify left-sided failure (elevated pulmonary wedge pressures), and arterial blood gases show hypoxia. Profound respiratory alkalosis occurs when patients hyperventilate when trying to increase their oxygenation; acidosis may occur with respiratory fatigue and failure. To improve the movement of air into and out of the chest, the patient will often sit upright to breathe and resist lying down.


Oxygen (in high concentrations by cannula, face mask, or nonrebreather mask) should be administered immediately. Assisted ventilation (continuous positive airway pressure [CPAP] or intubation with mechanical ventilation) may be needed to reach acceptable levels of PaO2 and improve acid-base balance. Morphine sulfate, nitrate vasodilators (IV nitroglycerin or nitroprusside) and loop diuretics are typically given to patients with cardiogenic pulmonary edema to improve dyspnea, alter preload and afterload on the heart, and promote diuresis. Angiotensin-converting enzyme inhibitors, inotropic drugs (digoxin), antiarrhythmic agents, beta-adrenergic blockers, human B-type natriuretic peptide, and phosphodiesterase inhibitors may be used in selected circumstances. Bronchodilators may also be administered. Depending on the underlying cause, invasive interventions may occasionally include coronary angiography, intra-aortic balloon pump therapy, or surgical interventions such as coronary artery revascularization or valve repair, or ventricular assist device therapy.


The outlook is good if the condition is stabilized or reversed with treatment.

Patient care

The patient's head is elevated; respirations and ventilatory effort are assessed. Oxygen is administered as prescribed, with care taken to limit the flow rate in patients whose respiratory drive is compromised. The lungs are auscultated for adventitious breath sounds such as crackles, gurgles, and wheezes, and the heart is assessed for apical rate and gallops. The patient is monitored for a cough productive of pink, frothy sputum. The skin is checked for diaphoresis and pallor or cyanosis. A medication history is collected, esp. for cardiac or respiratory drugs and use of recreational drugs. The patient's cardiac rate and rhythm, blood pressure, and oxygen saturation levels are monitored continuously. An intravenous (IV) line administering normal saline solution (NSS) is inserted at a keep-vein-open rate to provide access for medication administration. Prescribed first-line drug therapy is administered, and the patient's response to the drugs is evaluated. IV morphine slows respirations, improves hemodynamics, and reduces anxiety. It should be administered before initiating continuous positive air pressure (CPAP). CPAP improves oxygenation and decreases cardiac workload, thus decreasing the need for intubation and ventilation with positive end-expiratory pressure (PEEP). An indwelling urinary catheter is inserted to monitor the patient's fluid status; diuresis should begin within 30 min of administration of an IV loop diuretic. Pulmonary edema is a life-threatening respiratory emergency. Everyone involved with the patient must remain calm and quiet, provide ongoing reassurance, and validate everything occurring through basic and simply understood explanations. After the crisis resolves, health care providers should discuss with the patient his or her feelings about the episode and give thorough explanations of what occurred. The at-risk patient is taught early warning signs to act on immediately (such as weight gain or increasing peripheral edema), in an effort to recognize and prevent future episodes. Medications and dietary and lifestyle restrictions are explained (low-sodium diet, losing weight, smoking cessation), and written information provided for home review. The patient should be encouraged to enroll in a cardiac rehabilitation program (as applicable) for regular exercise tailored to his condition.

purulent edema

Edema caused by a local collection of pus.

reexpansion pulmonary edema

Abbreviation: RPE, REPE
Alveolar flooding that occurs after a collapsed or trapped lung reinflates, e.g., after the draining of a pleural effusion or the evacuation of a pneumothorax.

Reinke edema

See: Reinke edema

salt-induced edema

A form of edema worsened by excess sodium in the diet.

traumatic edema

Tissue swelling occuring after blunt or penetrating injury.
Synonym: post-traumatic edema

Cerebral edema

Fluid collecting in the brain, causing tissue to swell.
Mentioned in: Shaken Baby Syndrome

ce·re·bral e·de·ma

(ser'ĕ-brăl ĕ-dē'mă)
Brain swelling due to increased volume of extravascular compartment from uptake of water in neuropil and white matter.
Synonym(s): brain edema.
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