patho sheet #2 (dr.faisal)

بسم الله الرحمن الرحيم

** Edema
Edema: abnormal accumulation of fluid or water in the interstitium (intercellular space or between cells) and body cavities (peritoneal, plural, joint space).
In some books there is intercellular edema we are not going to discuss, only we’ll discuss the interstitium edema.
* There are major factors that produce edema:
1- Intercellular hydrostatic pressure.
- Which Try to push water from the intravascular compartment to the interstitium or into the intercellular compartment.
- increase (I.V.H.P) >>> increase leakage of water into the interstiuim >>> edema.
2- Intervascullar colloid osmotic pressure (oncotic pressure).
-which is largely due to presence of protein in the blood, this pressure drag water into the intravascular space.
- decrease (I.V.C.O.P) >>> increase leakage of water to the outside since it drives water to the cardiovascular system.
** Net result for these 2 farces:
- At the arteriolar end of the capillaries we lose water, and at the venuolar end of the capillaries we reabsorb water, but the amount of the reabsorb less than the lost >>> (normally) there are accumulation of interstial fluid.
- This intestinal fluid is being collected by the lymphatics, it is drained by the integral healthy adequate lymphatics.
3- lymphatics obstruction.
- There are many reasons that lead to lymphatic obstruction... Inflammation one of them.
- Elephantiatis >>> chronic inflammation in the inguinal region that rendering the lymphatics obstruction >> so that the lymph drainage in the lower limb and might be from the scrotum as well might be impeded or resisted >> thickening of the skin and underlying tissue >> like the elephant >> we call this lymph edema or lymphatic edema.

** Increase (I.V.H.P)
Can be localized or generalized.
1- Localized edema:
- Such as where there thrombosis in the lower limb, varicose vein. Thrombosis will render the blood augmented distal to that area >> this engorgement of the vein render higher intravascular hydrostatic pressure >> drive water to go outside.
2- Generalized edema:
-The classical example (Congestive heart failure)… if the right side of the heart failure, the Rt. Ventricular can’t pumps the blood to the different parts of the body then it’ll fire back itself on the Rt. Atrium that collect the blood via sup. And inf. Vena cava.
-So when there’s failure in the Rt. Side of the heart >>> then all over the body will not !!!! its blood completely into the Rt. Atrium >>> engorgement of veins with bld in all sites of the body >>> increase (I.V.H.p) >>> Generalized edema.
-Another example .. if the cardiac output was impaired (less than normal) >> one of the result is ischemia of the kidney, discondition ischemia of the kidney may trigger the increase secretion of (rennin) and rennin trigger a series events … Angiotensin I. Angiotensin II,…..etc >>> the end result is the secretion of (Aldosterone) by adrenal cortex >>> that cause retention of Na, so the body will reserve a large amount of water >>> edema.
-Aldesterone allows k to go out with urine more than normal.
-there’s 2 types of Aldesterone : primary and secondary.
- Type I (primary) >>>because of adenoma (tumor in the adrenal cortex).
- Type II (secondary) >>>hyperplasia of adrenal gland, juxtaglomerular cells of the kidney might secrete more and more of (Rennin), Rennin > Ang I > Ang II > Aldesterone, large amount of aldesterone >>> at the end cause edema.
-It may relate to ADH (Antidiuretic hormone), one of its functions >> cause the body to conserve water.This process may improve the efficiency of the cardiac output slightly, but we need other majors,other treatment, other than this because it may not be able to compensate the drop of bld to the kidney itself>>> so trigger this mechanism cause edema.
-Note: The congestion decrease slightly the cardiac output when it in all over the body, on the other hand if the congestion increase ( 3n 7ad m3yan ) >> increase blood pressure in it within the veins >> more bld to the RT. Side of the heart >> increase cardiac output slightly, but it will not change the shape of the kidney (sickle shape).
** Morphology
Localized edema
1- Pleural effusion or hydrothorax >> edema in the plural cavity (pure).
Pleurisy effusion >> edema in the plural cavity with element of inflammation(infection).


2- Peritoneal effusion or (Asaites) >> edema in the peritoneal cavity, another term
3- Pericardium effusion or hydropericardium.
The most common terms: hydroyhorax or pleural effusion, Asaites, pericardium effusion.
-when the edema is sever and generalized we call it >> Anasarca (extreme generalized edema)
** Subcutaneus edema:
-which is usually betting edema, it means that when the doctor presses by his finger on the malleolus bits, if there isn’t a local reason such as inflammation to cause localized edema then it is generalized edema due to RT. Sided heart failure.
-The dr. examines the malleolus When the patient is ambulatory,but when he is recumbent (bedridden),the dr. examines the sacrum not the malleolus.
- Non-betting edema: tendency of edema to undergo fibrosis (fibrogenic substance),it may be associated with other factors such as chronic inflammation (fibrosis is the end result).
-If the edema intracellular it’ll no bet.
** Renal edema:كلوية المنشأ often generalize and severe (Anasarca).
-Kidney doesn’t allow leakage of protein from it… so there isn’t edema due to this, but in cases of nephrosis and chronic renal diseases the kidney will become leaky, it leaks protein (glomerular leaky).
-The urine of the patient with kidney disease has a large amount of protein.( زلال)
-As a result of kidney disease (there’s injury to the kidney) the colloid osmotic pressure of plasma will drop >> render generalized edema.
-Renal disease (presence of protein in the urine) may cause swelling of the eyes.
-There is tendency that the renal edema (usually generalized) to collect first in the soft tissues. Among the soft tissues the first to be affected is the periorbetal tissue (eyes).
-Surly not any one who has a swelling eyes mean he has renal failure but this is one of the signs of the edema of kidney failure or generalized severe edema.
-Swelling eyes can be caused be Nephrotic syndrome and nephrosis.
** Pulmonary edema: it collects in the lower lobs of the lung that become much heavier than the usual,the alveolar spaces and alveolar septa widen and contain water.
** Brain edema:
-Any tumor in the brain, it’ll surrounded by a fluid of edema (localized edema).
-Localized infection, trauma, tumor in the brain >> will cause localized edema.
-Hypertension, encephalitis (inflammation of the brain) and sometimes meningitis (not just the brain substance but also the meninges) may cause generalized edema.
-The Brain is a very soft tissue, it is contained within a solid skull and covered by Dura matter. If this soft tissue swells due to edema for example >>1- the veins or (sinuses) will be compressed, 2- the ventricular (contain fluid) of the brain might be compressed that will compress the bld vessels.
-If the swelling increase more and more, then the swollen brain, the fluid will try to go outside the skull through certain features mainly by foramen magnum, so it will push the medulla and the cerebellum this lead to compromise the bld vessels specially the veins (drainage is compromise), and the bld supply might be impaired and some of these bld vessels due to pressure might be tearing.
-Also it might compromise one or more of the vital centers in the medulla (respiratory center) leading into instantaneous death. So it is very important to deal with brain edema.
-Falx cerebri >> Dura matter extention which descends in the longitudinal fissure between the cerebral hemispheres. ….. The swollen brain try to push itself from area under the falx cerebri ( subfalx) >> cause subfalcine herniation .
-Tentorium cerebelli >> extension of the Dura matter that separate the cerebellum from the cerebral cortex. ….. Since it is a hard structure, if there is a volume expansion above the tentorium, the brain can get pushed down partly through the tentorium >> this called herniation .
** Hyperemia and Congestion: increase in the amount of bld in a certain organ or tissue.
-One of them is due to increase pouring of blood, supply of bld, this is an active process they refer to it as hyperemia.
-the other one which is due to obstruction of the draining of the blood (venous blood),it is called congestion, the organ that engorged with venous bld may undergo atrophy.
* Hyperemia: active increase in the amount of the bld in certain organ
-all of them are active but the most important one is the physiological one.
1- Physiological hyperemia:
Examples:
-flushing of the face due to increase the amount of bld coming to the skin of the face due to arteriolar dilatation.
-increase in the bld flow that accompanies muscle contraction when you need to exercise.
-And by smelling of nice food you will find the GIT tries to activate itself and increasing its secretion so increasing of stomach vasculature lead to increase pouring of bld.
2-pathological hyperemia:
-when there is inflammation or fever, the body tries to get rid of this fever by arteriolar dilation.

3-Ractive hyperemia:
-that mean if you make a ligation of artery or a limb this will lead to obstruction
of the bld for awhile and then you remove this ligature (reopen the
vasculature ).the rebinding phenomena associated with the accumulation of certain metabolites that cause arteriolar dilatation.

-the reactive hyperemia is due to temporary interruption.

-ischemia for a while will cause reactive hyperemia.

-it may take length of time similar to ligation.

* Congestion: it is a passive condition where there is a bld engorgement in a particular part of an organ (any factor which might cause obstruction of venous return from an organ .)

-Sometimes if it is severe and or for along period then it might show rather bluish discoloration and that’s called cyanosis i.e decrease oxygenated bld and increase of unoxygenated bld .

-This passive congestion may show aclassical localized example like the Cirrhosis that is followed by portal hypertension , Cirrhosis not only fibrosis it is generalized associated with fibrosis and regenerative nodules so (generalization ,fibrosis and regeneration ) associated with portal hypertension because the circulation might be impaired.

-Generalized example: if there’s left sided heart failure so the left ventricle is failing then some of the bld will collect in the left atrium >>> then bld will go to the lung and at the end the lungs will be congested….this will lead to Increase hydrostatic pressure within the veins of the lungs >> then there is edema.
-pulmonary congestion will cause pulmonary edema.

-But in the RT. Sided heart failure the bld will be collected in the sup. And inf. Vena cava >> all the body will be affected except the lungs.
-Both RT. And left failure will affect each other.

-Any organ has congestion will contain high amount of bld much heavier than usuall (bloody organ) the bld will ooze if you make incision in that organ, and it may suffer from chronic hapoxia cause of stases of bld without being oxygenated well. Degeneration and hemosiderin may occure.
-In the passive congestion there will be increase in the hydrostatic pressure >>> dilatation of the capillaries >>> some of the bld might go outside the capillaries, RBC’s will collected in the alveolar spaces then to the alveolar septa. This hemoglobin will act as a foreign body >> macrophages come and eat up these hemoglabin.

-these RBC’s change to hemosiderin (contain iron, altered hemoglobin).

-these macrophages that eat the hemosidren we call it >>> hemosiderin laden macrophage or heart failure cells.

-hemosideren laden macrophage appears in distinctive color when staining with (H & D, classical basic stain).
-left sided cardiac failure lead to congestion in the lung so hemosiderin appear within macrophages and that’s called heart failure cells.

-long term polmunary congestion lead to heart failure cells (contain foreign bodys) that induce fibroses in the lung.
-heart failure cells+fibrosis >> brown induration … brown in color and tough.

-In the case of Rt. Sided heart failure there will be congestion all over the body but the most important organ that effected from this condition is the liver.

- We know the architecture of the liver which has a hexagonal shape and there is simply a portal triad - artery ,vein, and bile duct- whenever there is passive congestion ,the central vein will be congested with bld and therefore the most suffering of hepatocyte is the central hepatocyte which surround the central vein becoz there is no oxygen and no nutrient so it may suffer from atrophy and even necrosis,This condition will impart the color of the region between either hepatocyte which undergo atrophy and the adjacent central vein that congested with bld and well there will be variation in colors between the central area and the portal triad which only suffering lightly from atrophy and fatty change ,this variation in color will impart the liver when cutted to something like nutmeg) الطيب جوزة) (when cutted it has a special morphology due to variation of color).
-central cells suffer from atrophy, blue in color, while the peripheral cells suffer from fatty change, yellowish in color.

- So..left sided heart failure indicated heart failure cells , and right sided heart failure indicate nutmeg liver.
 Isra’a Drarjeh
22/11/201
Lec. 2
Dr. faisal