1 edema

HemodynamicsHemodynamicsEDEMAEDEMA

Dr.CSBR.Prasad, M.D.

12:40 PM SDUMCpath-CSBRP 2

Normal tissue fluid circulationNormal tissue fluid circulation

• There is continuous interchange of fluid between blood and tissues

• Fluid that leaks out of capillaries will be returned to the blood stream thru lymphatics

Constituents of Extracellularand Intracellular Fluids

Body Fluid CompartmentsBody Fluid Compartments

The total body fluid is distributed mainly between two compartments:

1- the extracellular fluid [1/3 rd] and the interstitial fluid [¾ of ecf] and the blood plasma [¼ of ecf]

2- the intracellular fluid [2/3rds]3- transcellular fluid [1-2 ltrs]

Two forces act to maintain normal fluid balance between intravascular and extravascular compartments

1- Hydrostatic pressure (HP): drives the fluid out ~35mm of Hg2- Protein osmotic pressure (Oncotic pressure - OP): retains the fluid in the capillaries ~25mm of HgArterial end: HP > OP = fluid forced out of capillaryVenous end: HP < OP = fluid is attracted into the vessel

Note: some fluid enters the lymphatic channels. This may be due to… - partly due to tissue pressure - partly due to OP of proteins in the lymphatics

Normal tissue fluid circulationNormal tissue fluid circulation

Body water control Body water control In addition to those forces operating at

capillary level there are other mechanisms which influence the movement of fluid within the body in a general manner:

1. Fluid intake2. Integrity of the kidneys3. Hormone activity (Aldosterone, ADH)

Definition:The term edema signifies increased fluid in the interstitial tissue and tissue spaces. Depending on the site, fluid collections in the different body cavities are variously designated Hydrothorax, Hydropericardium, & Hydroperitoneum (Ascitis)

Anasarca is a severe and generalized edema with profound subcutaneous tissue swelling.

EdemaEdema ( (GrGr oidemaoidema==swellingswelling))

Increased Hydrostatic PressureImpaired venous return

Congestive heart failure

Constrictive pericarditis

Ascites (liver cirrhosis)

Venous obstruction or compression

Thrombosis

External pressure (e.g., mass)

Lower extremity inactivity with prolonged dependency

Arteriolar dilation

Heat

Neurohumoral dysregulation

Sodium RetentionExcessive salt intake with renal insufficiency

Increased tubular reabsorption of sodium

Renal hypoperfusion

Increased renin-angiotensin-aldosterone secretion

InflammationAcute inflammation

Chronic inflammation

Angiogenesis

Reduced Plasma Osmotic Pressure (Hypoproteinemia)

Protein-losing glomerulopathies (nephrotic syndrome)

Liver cirrhosis (ascites)

Malnutrition

Protein-losing gastroenteropathy

Lymphatic Obstruction

Inflammatory

Neoplastic

Postsurgical

Postirradiation

List of pathophysiologic List of pathophysiologic categories of edema categories of edema

SitesSites

Although any organ or tissue in the body may be involved, edema is most commonly encountered in:

• subcutaneous tissues, • the lungs, and • the brain.

Note: Severe, generalized edema is called anasarca.

Clinical importanceClinical importanceEffects of edema: may range from merely annoying to fatal

• Subcutaneous tissue edema in cardiac or renal failure is important primarily because it signals underlying disease; however, when significant, it can also impair wound healing or the clearance of infection.

• Pulmonary edema can cause death by interfering with normal ventilatory function. Not only does fluid collect in the alveolar septa around capillaries and impede oxygen diffusion, but edema fluid in the alveolar spaces also creates a favorable environment for bacterial infection.

• Brain edema is serious and can be rapidly fatal; if severe, brain substance can herniate (extrude) through, for example, the foramen magnum, or the brain stem vascular supply can be compressed. Either condition can injure the medullary centers and cause death.

EdemaEdema

Conditions which interfere with the pressure gradients systems results in edema:

1- >HP (esp. in the venous end)2- <OP (blood)3- Alterations in capillary permeability

(ex: Inflammation)4- Impeded lymphatic drainage

1-Increased HP 2-Decreased OP

3-Increased capillary permeability

4-Impaired lymphatic drainage

General Pathogenetic factors

Hydrostatic edema

• Cardiac edema• Portal edema• Venous edema• Osmotic edema

Oncotic edema

• Vascular edema• Lymphedema

Hydrostatic edema

Portal edema:

Edema in the region drained by portal vein (esp. in the intestines) or occuring in the setting of portal HT

Ascites only occurs where the postsinusoidal vessels are constricted, as can occur in cirrhosis of the liver

Budd-Chiari syndromeBudd-Chiari syndrome

Ascites only occurs where the postsinusoidal vessels are constricted

Cirrhosis

Ascitis Ascitis A special form of hydropsA special form of hydrops

Hydrops fetalisHydrops fetalis

Hydrostatic edema

Venous edema :

Edema occuring in the regions with impaired venous drainage

Etiological factors:1. Venous occlusion (thrombosis, compression)2. Venous insufficiency (varicosities)

Varicose veins Varicose veins

Superior Superior venacaval venacaval syndromesyndrome

Superior venacaval syndromeSuperior venacaval syndrome

Photographs of the patient showing the reduction in swelling of the face, neck and upper extremities

(A) At initial presentation and (B) after treatment (hospital day 8)

Pleural effusion

Chylothorax

The chest radiograph here demonstrates a large pleural effusion nearly filling the left chest cavity.

Bilateral Pleural effusion

Osmotic edemaEdema resulting from an imbalance of

sodium chloride and water in the blood

Etiological factors:1. Hypotonic hydration (excess water

intake, High ADH) - hyponatremia2. Hypertonic hydration (increased intake

of Na+, Conn’s syn, Cushing’s syndrome) - hypernatremia

Oncotic edemaEdema resulting from low colloidal osmotic

pressure due to protein deficiency

Etiological factors:1. Proteinuria – Nephrotic syndrome2. Protein losing enteropathy3. Starvation (protein malnutrition)4. Cirrhosis of liver (deficient albumin)

Vascular edema – increased vascular permeability

Edema resulting from generation of inflammatory mediators > increased vascular permeability

Etiological factors:1. Pathogens and their toxins2. Immune complexes3. Chemical agents (mustard gas)4. Toxic metabolites (uremia)5. Release of chemical mediators of inflammation6. Persistence of complement factors (inhibitor

deficiencies)

Lymphedema

Edema occuring as a result of functional and / or obstructive impairment of lymph drainage from tissue

Etiological factors:1. Primary lymphedema (congenital defects)2. Secondary lymphedema (oblockage)

Normal lymph drainage

• Plasma along with the proteins passes in to the interstitium (half of plasma proteins)

• They are taken by the lymphatics• Returned to the blood by thoracic duct

Properties of lymphatic Properties of lymphatic channelschannels

• Tube-like• Numerous valves• Drains fluid back to blood-stream – passes

through at least one lymph-node.• Present in all tissues except

– CNS, Eyeballs, Internal Ear, Epidermis of the skin, cartilage and bone.

Taken from Guyton & Hall – Human Physiology and Mechanisms of Disease

Schematic of lymphatic channels

Taken from Colour Atlas of Anatomy – Roden, Yokochi and Lutjen-Drecoll

Thoracic ductThoracic duct

Lymphedema

Etiological factors:Primary lymphedema (congenital defects)• Milroy’s edema• Obliterative lymphatic disease (sclerosis

of lymph vessels at the calf)

LymphedemaEtiological factors:Secondary lymphedema (oblockge)• Lymphagiosis carcinomatosa• Recurring lymphangiitis (erysipelas)• Lymph vessel scarring after burns• Sclerotherapy / LN block dissection• Meigs’ syndrome

Lymphedema

Special forms of lymphedema:1. Anasarca 2. Hydrops

Hydrops: is excessive accumulation of watery fluid in existing organ cavities.

Lymphedema - sequelae

1. Sclerosis2. Dermatopathy3. Stewart-Treves syndrome

FilariasisNon-pitting edema

Dermatopathy

Peau d’ orange – Breast carcinoma

Breast carcinoma - lymphedema

Peau d‘ Orange (orange peel)

Inflammatory carcinoma – dermal lymphatic involvement

Lymphangitis carcinomatosa

Stewart-Treves syndrome:Lymphedema due to axillary

lymphnode dissection – for breast cancer – and she has developed malignant tumor (lymphangiosarcoma) of upper arm

Dilated lymphatics in instestinal wall

Milroy’s edemaMilroy’s edema

Milroy’sMilroy’s edemaedema

Milroy’s edemaMilroy’s edema

Chylothorax

Cerebral edema

Def: Diffuse / local accumulation of fluid in the brain with a resulting increase in the volume of the brain tissue

According to the magnitude: it may be1. Generalized (involving entire brain)2. Perifocal edema (inflammation, tumors)

Cerebral edema

Causes: 1. Vasogenic CE2. Cytotoxic CE3. Interstitial CE4. Hyposmotic CE

Cerebral edema

Causes: Vasogenic CEMechanism: disruption of BBBBrain tumorsCerebral infarctsInjuryMassive cerebral hemorrhageCerebral abscess

Cerebral edemaCytotoxic CEMechanism: disruption of BBB secondary

to collapse of energy metabolismLoss of ATP-dependent ion pump >

passive inflow of water in to the cellsIschemiaLiver failureCyanide poisoning

Cerebral edema

Interstitial CEMechanism: impaired drainage of CSFImpaired drainageObstructive hydrocephalus

Cerebral edema

Hyposmotic CEMechanism: hypervolemia with

hyponatremia

Cerebral edema

Complications CEHerniation of brain tissue (sub falcine,

transtentorial, tonsillar)Clinical symptoms: • Cardiac arrest• Respiratory paralysis

Gross: The surface of the brain with cerebral edema demonstrates widened gyri with a flattened surface. The sulci are narrowed.

Herniation:

1-Sub falcine

2-Transtentorial

3-Tonsillar

• Acute brain swelling in the closed cranial cavity is serious. Swelling of the left cerebral hemisphere has produced a shift with herniation of the uncus of the hippocampus through the tentorium, leading to the groove seen at the white arrow.

• Acute cerebral swelling can also often produce herniation of the cerebellar tonsils into the foramen magnum.

• coronal view demonstrates a cysticercus cyst of the brain which has a dark cystic center and distinct bright border with gadolinium enhancement.

• This computed tomographic (CT) scan of the head in transverse view demonstrates an abscess in the brain in a patient who had septicemia

• This magnetic resonance imaging (MRI) scan of the head in sagittal view reveals the presence of several well-circumscribed metastatic tumor nodules of the brain.

Hydrocephalus

Papilledema

Urticaria - Hives• Crops of patches involving the skin which are

erythematous, edematous and itchy• Secondary to mast cell degranulation mediated

by immune mechanisms• Vasoactive substances are released resulting in

vasodilataion and increased vascular permeability

• Factors: Histamine, PAF, LT-C4, D4, E4, PG-D2

Urticaria - Hives

Coldurticaria: Ice cube test for cold urticaria

Angioneurotic edema

Deficiency of C3 convertase inhibitorResult: unapposed activation of complement

with resultant vasoactive substances C3a, C5a et.c. causing edema

Sites: Lips, Tongue, Larynx.

Classical complement pathway

Angioneurotic edema

TermsTerms

• Ascites• Hydrothorax• Anasarca• Lymphedema• Pulmonary edema• Cerebral edema• Angioneurotic edema

Pulmonary edemaPulmonary edema


The balance between these forces is relatively fine and can be easily upset so that edema can occur rapidly:

Cardiac failure & over transfusion / infusion increased HPInhalation of irritant gases & inflammation increased capillary permeability

The smooth, glistening pleural surface of a lung is shown here. This patient had marked pulmonary edema, which increased the fluid in the lymphatics that run between lung lobules. Thus, the lung lobules are outlined in white.

Taken from Sternberg`s HISTOLOGY for PATHOLOGISTS

The alveoli in this lung are filled with a smooth to slightly floccular pink material characteristic for pulmonary edema. Note also that the capillaries in the alveolar walls are congested with many red blood cells.

Heart failure cells

Pulmonary edema

Generalized edemaGeneralized edema

• Cardiac edema• Renal edema• Famine edema (Malnutrition)

Cardiac edemaCardiac edema

Generalized edema - CardiacGeneralized edema - Cardiac

Systemic circulation

vs.

Pulmonary circulation

Taken from

Robbins Pathologic Basis of Disease

↑↑ JVP

Acute nephritisNephrotic syndrome

Mechanism: 1. <OP due to protein loss thru the

kidneys2. Na+ and H2O Retention

Generalized edema - RenalGeneralized edema - Renal

Renal edemaRenal edema

Acute NephritisAcute Nephritis NephrosisNephrosis

Degree of edema Slight Marked

Distribution Around eyes Generalized

Proteinuria Slight Marked

Plasma OP Normal Reduced

Mechanism Retention of fluid Low plasma OP

Two forms of renal diseases are associated with edema:

1- Acute nephritis & 2- Nephrotic syndrome

Malnutrition > [Food low in proteins] > Protein deficiency > reduced OP > generalized edema

Malnutrition > vitamin deficiency(B1) > Beri-Beri > cardiac failure

Generalized edema - FamineGeneralized edema - Famine

Pitting edemaPitting edema

Pretibial myxedema(Hyperthyroidism)

Oedema

• Water compartments• Movement of water between the

compartments• Causes of oedema• Pulmonary oedema• Cerebral oedema

Taken from Underwood – General and Systemic Pathology

Taken from Sternberg`s HISTOLOGY for PATHOLOGISTS

Taken from Colour Atlas of Anatomy – Roden, Yokochi and Lutjen-Drecoll

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1 edema

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