7th lecture (edema, shock, congestion)

Question 1

Edema definition?

Answer 1

low protein content extravasated fluid, derived from the blood, (in contrast to exudate)
This is called Transudate, it is found freely in the abdominal cavities and other body cavities (pleura cavity, and interstitial tissue in the organs)
Low specific gravity.

Question 2

define Exudate?

Answer 2

protein and cell rich fluid. characteristic in inflammation

Question 3

what are the determinants of the edema?

Answer 3

• intravasal hydrostatic pressure
• colloidosmotic pressure in the vessels.
• the tissue also has a colloidosmotic pressure
• lymphatic circulation
• sodium concentration in the blood
• permeability of the capillaries.

Question 4

What causes edema?

Answer 4

There disturbance in the micro-circulatory units.

• Increase in colloidosmotic pressure in the blood (causing more fluid to leave)
• increased capillary permeability (more fluid leaves)
• increased hydrostatic pressure in the venous part (low amount of reabsorption)
• lymphatic insufficiency
• Na and water retention (high sodium means water is also removed)

Question 5

describe the simplified schematic of circulation in respect to edema?

Answer 5

Arteries have a higher pressure therefore fluid leaves circulation
Veins have a lower pressure therefore fluid is reabsorbed
The interstitial fluid can also be removed by the lymphatic circulation. (NOTE lymph vessels have NO blind ends)

Question 6

2 major categories of edema formation

Answer 6

• Localized edema formation

- generalized edema formation

Question 7

what are some examples of localized edema formation?

Answer 7

• venous outflow has a problem
• lymphatic circulation is disrupted
• inflammation (do to increased capillary permeability)
• allergic hypersensitivity
• hypoxia (brain especially causes edema)

Question 8

what are some examples of generalized edema formation?

Answer 8

• hypalbuminemia (low levels of albumin in the blood, and since albumin makes up 55-60% of blood protein, so its decrease causes decrease in blood colloid pressure and thus edema)
• Right sided heart failure
• Rh (ABO) incompatibility (for severe infiltration in babies)

Question 9

what causes edema in the legs?

Answer 9

deep vein thrombosis of femoral vein disturbing the fluid reabsorption.

Question 10

what is fluid accumulation in the abdominal cavity called?

Answer 10

ascities

Question 11

what is the fluid accumulation in the thoracic cavity called?

Answer 11

hydrothorax

Question 12

Liver Cirrhosis basic description?

Answer 12

cirrhosis is the scarring of the liver. The excessive amount of connective tissue divides the liver into pseudo-nodules of the liver. This excessive amount of connective tissue interferes with the circulation from the portal vein to the inferior vena cava. This causes hypertension in the portal circulation which makes it difficult to reabsorb fluid from the abdominal cavity.
Fluid will accumulate in abdominal cavity (ascities)

Question 13

describe the superior vena cava syndrome.

Answer 13

Mediastinal lymphoma results in large lymph nodes that compress the superior vena cava. Causing edema of the face, neck and shoulders. This is potentially life threatening. It is called superior vena cava syndrome.

Question 14

what to check for in the autopsy room?

Answer 14

squeeze the lungs to check for edema. It is caused by either cardiac or non-cardiac causes.
90-95% do to cardiac causes, mostly acute left sided heart failure;
-acute myocardial infraction and large endocarditis causing the abnormal valvular movement
-myxoma benign tumor in the heart left atrium for example, this could block normal blood flow from atrium to ventricle.
-dilation of the left ventricle (1st step of the hypertension)
-artificial valve (if this valve could become thrombotized causing problems for atrial to ventricular blood flow)
EXTRA-CARDIAC (rare); neurogenic edema can cause pulmonary edema (the mechanism for it is obscure)
-uremia (renal insufficiency) the unexcreted nitrogen containing materials are toxic and are directed to the capillaries and the leakage of the capillaries will cause pulmonary edema.
ALTITUDE RELATED PULMONARY EDEMA: exercise at high altitude will case pulmonary edema.

Question 15

lymph edema definition?

Answer 15

the edema is unable to remove the excess of interstitial fluid, which accumulates.
EXAMPLE: breast cancer treatment where the breast is removed and also the metastatic axillary lymph nodes are also removed. This causes edema to develop in the arm on the side where the lymph nodes where removed, (localized lymph edema). This can be avoided by removing only the lower level lymph nodes if possible during breast cancer treatment.

Question 16

Where can edema best accumulate?

Answer 16

in areas with loose connective tissue;

• Peri-orbital region
• scrotum
• bulbar region (An area of the brain composed of the cerebellum, medulla and pons)

Question 17

What happens when the edema accumulates in areas that are connective tissue rich? I.e. not flexible/expandable (brain)

Answer 17

In this case the edema works its way into the areas surrounding it that are a little bit looser. Such as in the case of a tooth inflammation edema, that may work its way into the face.
The surface of the brain during edema becomes smooth as the gyri are pushed out. The brain gets compressed against the foraman magnum which is fatal since in that area of the brain the respiratory centers are located.

Question 18

why is allergic reaction edema life threatening?

Answer 18

They can affect the upper airways. NOTE: always ask the patient if they know about any allergies. Since edema can develop in the neck and narrow the respiratory tract.

Question 19

what is the link between hypoxia and edema of the brain?

Answer 19

in hypoxia the membrane enzymes that are responsible for the Sodium, Potassium exchange are blocked. Thus all the cells will retain a larger amount of Sodium and thus water also accumulates and thus the cells swell.
Upto: 700grams
This is called cytoxic edema, since the enzymes that are responsible for exchange are blocked.

Question 20

what is vasogenic edema?

Answer 20

Edema of the brain that occurs when there is a destruction of the blood brain barrier.

Question 21

what is cytoxic edema?

Answer 21

when the membrane bound transporters are disrupted leading to cell death.

Question 22

what is the focal edema?

Answer 22

similar to that of cytotoxic edema; enlargement of the brain and herniation of parts of the brain through the foreman magnum.
Any circumscribed lesion in the brain can be called “focal” (CIRCUMSCRIBED: confined to a limited area circumscribed patches of hair loss)
This focus can be hemorrhage or abscess, etc. Around this focal area an edema can form.

Question 23

what kindof edema form in the brain?

Answer 23

cytotoxic
perifocal/vasogenic
Do to the limited room in the brain, all forms of edema could be dangerous.

Question 24

What could occur during hypoalbuminemia?

Answer 24

there is a decrease in colloid osmotic pressure inside the vessel, do to decreased Albumin levels. Thus there will be a generalized edema formation in the body.

Question 25

what does edema of the face mean?

Answer 25

hypoproteinemia. This could be do to renal diseases as protein is lost in urine (proteinemia)

Question 26

where does edema develop during Right sided heart failure?

Answer 26

The edema follows the gravity. The lower legs develop edema but the face does not. This type of edema is characterized as “pitting edema”; if you press on the legs the outline of your finger persists.

Question 27

What is pitting edema? what causes it?

Answer 27

If you press on a swollen area and an indentation or pit remains.
In contrast to when the mucous-saccarides accumulate where pressing on the surface causes nothing.
pitting edema is classically do to renal diseases, where excessive protein is lost in the urine, called Nephrotic syndrome

Question 28

what is Nephrotic syndrome

Answer 28

a kidney disorder that causes your body to excrete too much protein in your urine. Nephrotic syndrome is usually caused by damage to the clusters of small blood vessels in your kidneys that filter waste and excess water from your blood. The RESULT:

• basement membrane of the glomeruli are very permeability
• hypoalbuminemia
• This results in generalized edema
• hypercholesterolemia, since low albumin induces excessive cholesterol production in the liver.

Question 29

Describe the generalized edema that occurs do to Right sided heart failure?

Answer 29

Pulmonary edema is caused by acute left sided heart failure, this causes and “overfill” of the pulmonary tissue.
Right sided heart failure in contrast (do to emphysema, chronic bronchitis, COPD, obesity, tuberculosis), there is engorgement of blood in the areas of the upper and upper and lower venous system. Thus the right side is unable to pump the necessary amount of the blood towards the lungs, and thus the intravenous pressure is increased at the area at the IVC and SVC.

Question 30

what are the classical signs of right sided heart failure?

Answer 30

• Accumulation of fluid (transudate) in the pericardial sac, (hydropericardium)
• Bilateral hydrothorax (fluid end up in the pleura area since the pressure ends up in the azygo and hemiazygos)
• ascites (peritoneal cavity, causing abdominal swelling)
• anasarca: the general swelling of the whole body

Question 31

what occurs during Rh incompatibility during pregnancy?

Answer 31

hydrops fetalis: large amounts of fluid build up in a baby’s tissues and organs causing extreme swelling.
It can occur in a intrauterine infection.

Question 32

congestion definition?

Answer 32

a passive process of engorgement of blood in the venous system.
In contrast to active hyperemia that requires chemical mediators like in inflammation, drugs, hormones.

Question 33

Congestion 2 types?

Answer 33

localized (passive hyperemias)
generalized hyperemia, classically results from right sided heart failure, in which the heart is not correctly oxygenated. The patient has a blue-ish color, cyanosis. In the stomach and duodenum the mucosa turns blue do to the poor oxygenation of the blood.

Question 34

what happens to the liver during right sided heart failure?

Answer 34

the liver and the spleen is enlarged (hepatomegaly + splenomegaly = hepatosplenomegaly)
On the cut surface of the liver you will see the classical pattern of nutmeg liver. (area around central vein are necrotic do to hypoxia)
The pyramids are extremely blueish in the kidney and the veins on the surface of dilated do to the congestion.

Question 35

Nutmeg liver is a good sing of …?

Answer 35

• Right sided heart failure
• Hepatic vein obstruction. The resulting hypoxia causes fatty degeneration of the hepatocytes, Thus there is a characteristic red-yellow pattern of the liver.

Question 36

what occurs during chronic persistent congestion

Answer 36

• enlargement of the organs; hepatomegaly, splenomegaly
• induration; the organ become firmer, an increase in the fibrous elements in tissue commonly associated with inflammation and marked by loss of elasticity and pliability.
• Congestion induced fibroblast proliferation.
• its very difficult to scrape material off of the cut spleen do to the fibrous accumulation.
• chronic congestion can also cause this (fibrous accumulation) in the lungs.

Question 37

what happens if the congestion involves the skin?

Answer 37

the skin becomes atrophied and thin because of the increased blood supply.

Question 38

what happens if the congestion involved the organs with loose connective tissue (testicle, small intestine)

Answer 38

necrosis of the organ occurs. Edema also forms do to the increased venous pressure.

Question 39

what happens in the lungs during prolonged chronic congestion?

Answer 39

The capillaries will be ruptured and RBC’s will enter the alveoli lumen where the alevoli macrophages will eat them up and will transform them into a brown-ish pigment hemosiderin.
hemosiderin is always seen around the bleeding and congested areas.
Prussian blue stain is used to differentiate between the brown melanin and brown hemosiderin, the stains changes the brown color to blue thus indicating hemosiderin.

Question 40

Congestion in the lung is cased by?

Answer 40

Chronic left sided heart failure. The brown hemosiderin accumulation, and connective tissue also accumulates after a while. This result in a brown induration of the lung (accumulation of the fibrous connective tissue).
When the patient is coughing, the hemosiderin laden macrophages may end up in the sputum (spit), these are the so called HEART FAILURE CELLS. Indicating chronic left-sided heart failure.

Question 41

Causes of chronic congestion?

Answer 41

Thrombus. If a thrombus were to occur in a major vein (IVC, femoral vein, iliac vein) there will be a massive cyanotic congestion in the give lower leg, and edema occurs. Localized congestion occurs via thrombus in the venous system.
For example the testicle or ovaries could be twisted causing congestion.

Question 42

How can you see right sided heart failure in autopsy room?

Answer 42

These is massive dilation on the right lumen of the heart.

Question 43

what is postthrombotic syndrome?

Answer 43

Congestion causes thinning of the skin. FOR EXAMPLE: deep vein thrombosis in popliteal vein. Blood flow goes through the superficial vein then through the perforator vein and then deep veins. Thus congestion in the superficial veins, the capillaries rupture, and blueish effected area develops and hemosiderin laden macrophages are released creating a more brownish color area.
The skin become atrophied and the thin skin results in a slow healing wound. Thus a crural ulcer forms.

Question 44

Shock definition?

Answer 44

circulatory disturbance that causes inadequate perfusion of an organ. This leads to hypoxia in the given organs/tissue, there is a generalized tissue dysfunction.
There is a stereotypical reaction of shock called; hyper-reactvity which is caused by elevated sympathetic activity. The artery and venous parts are constricted, there will be stasis in capillaries, and hypoxia and acidosis causes organ dysfunction.
The systemic hypertension reduces kidney perfusion and thus glomerular filtration rate is also reduced. Patient develops anuria (no urine made by kidneys), endogenic toxicosis.

Question 45

Define hypovolemic shock?

Answer 45

-blood loss (hemorrhagic shock)

Question 46

Traumatic shock description?

Answer 46

NOTE: this has a very complex mechanism.

• severe pain
• cytokine store from necrotic tissue

Question 47

anaphylactic shock description?

Answer 47

-there is a general vasodilation, the blood pools in the capillary system.

Question 48

Cardiogenic shock description?

Answer 48

40% of the left ventricular myocardium has been necrotized. Reduced cardiac output.

Question 49

Septic shock description?

Answer 49

also called ENDOTOXIC shock. (HAS a very complex mechanism). Sepsis develops when the body has an overwhelming response to infection. peripheral vasodilation occurs.

Question 50

Toxic shock description?

Answer 50

made by staphylococcus and tetracoccus. Some strains of staphylococcus produce TSS1 toxin, which is highly potent.

Question 51

what can be seen in the autopsy room in terms of SHOCK? (morphologically)

Answer 51

• shock kidney (classical sign) the cortical area is pale and necrotised. On the other side there is a very sharp border between the extremely pale and extremely bluish-red pyramidal system.
• Stomach: multiple erosions may occur within hours and the superficial mucusal layers are necrotised causing beeding
• Lung (shock lung or ARDS; adult respiratory distress syndrome), the epithelial cells and the endothelial cells are both destroyed, the lung is heavy, edematous, hemorrhagic areas and atelectatic areas, hyperinflated areas. The shock lung feels like a “dog ear”