• distribution of water, nutrients
• remove wastes

• hydrostatic pressure
• osmotic forces

capillary hydrostatic pressure

interstitial oncotic pressure

plasma oncotic pressure

interstitial hydrostatic pressure

Interstitial hydrostatic and oncotic pressure tend to be low

• hydrostatic P greater than capillary oncotic P
  • water filter into interstitial space

• movement of water out of plasma compartment at arterial end cause hydrostatic pressure in capilary to decrease
• leads to plasma oncotic pressure at venous end being greater than hydrostatic pressure
• water reabsorbed

• cause by increase in forces favoring filtration
• excess fluid in interstitial tissue spaces, body cavities

• non-inflammatory
  • transudate (protein poor edema fluid)
  • increased capillary hydrostatic P
  • decreased plasma oncotic P
  • lymphatic obstruction
  • sodium, water retention
• inflammatory
  • proteins, inflammatory cells
  • exudate- protein rich edema

• usually in the setting of inflammation
  • swelling, "tumor"
• burns- disrupt permeability of local vasculature
• venous or lymphatic obstruction
  • common cause of edema in limb

• causes
  • CHF
  • nephrotic syndrome
• anasarca- extreme generalized edema in SubQ tissues, visceral organs, body cavities

• increase venous or arterial pressure leads to impaired venous return causing passive congestion
  • CHF
  • constructive pericarditis
  • cirrhosis
  • venous obstruction or compression
    • LE inactivity
    • DVT
    • external pressure
• arterial dilation cause active congestion
  • heat
  • inflammation

• localized increase has blocked venous outflow (ex: DVT)
• generalized increase
  • right heart failure (usually due to left sided failure or right valve disease)
  • CHF

• half of all CHF patients admitted to hospital die in year
• reduced cardiac output leads to poor organ perfusion (not enough blood meeting body demands)
• most often due to coronary artery disease

• decrease blood flow (poor perfusion)- forward failure
• daming of blood in pulm. circ. (backward failure)
  • Pulm. V P increases, transmitted back to the capillaries

• pulm. capillaries pressure forces fluid out
• fluid drained by lymphatics
  • so capacity is exceed, so fluid accum. in interstitium, alveolar sacs

• activate symp. NS
• leads to arterial constriction causing decreased renal perfusion
• activate RAA system
• retention of sodium of water
• extra fluid only contributes to venous pressure

SO WORSE EDEMA

• dyspnea awakened by episodes of SOB
• physical exam
  • JV distension
  • peripheral edema
  • congested liver, spleen
  • pleural effusion, ascities
  • rales (crackling breath sounds)

• enlarged heart
• dilated vasculature

• decrease protein
  • excessive loss
    • nephrotic syndrome
  • decreased synthesis
    • diffuse liver path. (cirrosis)
    • protein malnutrition
• movt of fluid out of capillary

• decrease plasma volume
• stimulat RAA axis leading to sodium and water retention

• tumor
• fibrosis
• radiation
• surgical removal

• vascular changes play more role in acute inflam. after injury
• arteriole dilation, open capillary beds
  • increase blodo flow, capillary hydrostatic P

• most often involves subQ tissue, lungs, brain
  • but any organ, tissue may be involved
• range from insig. to fatal
  • extent
  • distrib.

• diffuse or dep
  • dependent- influenced by gravity, time
    • ex: CHF- legs and feet in mobile people, back of bedridden
• may
  • restrict blood flow
  • wound healing
  • increase risk of infection

• LM
  • clearing, separation of EC matrix
• better seen in gross examination

• seen in:
  • left heart failure
  • renal failure
  • lung infection
• gross exam
  • wet, heavy
  • frothy, typically blood tinged fluid

• alveoli filled with homogeneous, pink staining fluid, bubles
• additional finding dependent on cause

• impair oxygen exchange
• bacterial growth, pneumonia

• very lethal because no lymphatics, confined by skull
• cause
  • comprimised blood supply
  • distort structure
  • interfere with function

• def.- increase blood vol. in tissue
• passive
  • organ, tissue engorged with venous blood
  • caused by impaired venous outflow
    • local- DVT
    • system- cardiac failure

• stasis of poorly oxygenated blodo casues chronic hypoxia, cell degen, death
• capillaries may rupture
• RBC's eaten up by macrophages causing accumulation of hemosiderin laden macrophages

congested

heavy

hemorrhagic

wet

• alveolar capillaries distended with blood
  • may be associated with alveolar edema or intraalveolar hemorrhage

• central veins, sinusoids distend with blood
• degeneration of centrilobular hepatocytes
  • farthest away from blood supply

• periportal hepatocytes more alive due to proximity to portal triad
• centrilobular necrosis
• blood fills central veins, sinusoids

portal HTN

• def.- excessive amount of blood in the tissue
• cause
  • increase blood flow into organ due to arteriole dilation and recruitment of capillaries
• tissue become redder due to filling with oxygenated blood

• decrease in platelets
• platelet deficiency
• coagulation factor deficiency
• capillary fragility

• petechia
• purpura
• ecchymoses (bruises)

• pinpoint hemorrhages in skin, conjuctiva, mucous membranes, or serosal surfaces

• larger hemorrhages in the skin that may be associated with
  • trauma
  • local vascular inflam.
  • increased vascular fragility

• larger subQ hematomas that occur with trauma
• can be exacerbated by any condition associated with increase risk for hemmorhage

• always due to injury of vessel including:
  • trauma
  • atherosclerosis
    • weaken aorta wall
    • ballon to form aneurysm
  • erosion of vessel wall by inflammation or neoplasm

• volume of blood loss
• site of hemorrhage
• rate of blood loss

• GI hemorrhage
  • peptic ulcer
  • esophageal varices
• rupture of aortic aneurysm leading to massive retroperitoneal hematoma
• trauma
  • gunshot
  • blunt force trauma

• portal HTN
• increase resistance to blood flow
• distortion of architecture, fibrosis

• dilated tortuous vessels
• located directly beneath epithelium of distal esophagus, proximal stomach
• rupture leads to massive hemorrhage

• cause- loss of circulated blood volume, causing impaired tissue perfusion and cellular hypoxia
• at first injury is reversible, but if persisit, injury to cells become irreversible

• increased intracranial pressure
• herniation
• compression of vascular supply

• rapid accumulation of blood in pericardial sac
• this prevents right ventricle from filling during diastole
  • cause sudden drop in CO and death

• scaring of liver obstruct portal blood flow leading to portal HTN, causing increased hydrostatic P
• decrease synthesis of albumin cause decreased plasma oncotic pressure
• increased transudation of lymph from liver capsule causes ascities
• causes decreased effective blood volume, leading to RAA activation
• further volume expansion promote ascities and edema