pathology: hemorrhage- information

coagulation

interaction between platelets and clot factors. the end result is that you activate thrombin, which catalyzes the conversion of fibrinogen to fibrin, forming a clot. platelets are formed from megakaryocytes in the bone marrow. (biggest cells, multinucleate)

esophageal varices

upper GI bleed in which you have dilation of the esophageal veins near the surface of the esophagous that can lead to rupture and hematemesis (vomited blood) or aspirated blood into the trachea

hematemesis

vomited blood associated with esophageal varices

cardiogenic shock

acute heart failure causing systemic hypotension

types of shock

hypovolemic shock cardiogenic shock neurogenic shock anaphylactic shock septic shock

ecchymoses

"larger" bruise (>1 cm) -spread of extravasated blood in a thin layer under the skin (bruise) causing FLAT discolorations. -usually occurs secondary to trauma -size is determined by severity of trauma

hemostasis- definition, what does it involve. what happens when it goes wrong?

1) blood clotting. 2) involves --> a) blood vessels -->B) platelets -->C) coagulation system- (proteins). 3) when any of these three components goes wrong, you have the potential for disordered hemostasis= hemorrhage

clinical patterns of hemorrhage

1) petechiae 2) purpura 3) ecchymoses 4) hematoma

Clinical examples of hemorrhage that we discussed in class that you should recognize

1) subdural hematoma 2) hemoperitoneum (from surgery, ectopic tubal pregnancy, liver lacerations and spleen ruptures) 3) hemothorax 4) hemopericardium (cardiac tamponade, myocardial rupture) 5) Upper GI bleeds (esophageal varices, gastric ulcer) 6) Lower GI bleed (colon diverticulosis) 7) cerebral hemorrhage (hypertensive and thrombocytopenic)

systemic effects of hemorrhage

1)exsanguination 2) hypovolemic shock 3)anemia of chronic blood loss

petechiae and what it's associated with

1-2 mm of tiny hemorrhages into the skin, mucous membranes or serosal surfaces (visceral or parietal surfaces of pleaural or peritoneal cavity) -associated with A) locally increased intravascular pressures B) low platelet counts (thrombocytopenia) C) defective platelet function

platelets

bags of cytoplasm (no nucleus) derived from megakaryocytes in the bone marrow. -much much much smaller than RBCs. accumulate in clusters.

cardiac tamponade leads to hemopericardium

bleeding into the space between the visceral and parietal pericardium, leads to hemopericardium. the blood can't relax during diastole as a result/ diastolic filling is restricted (decreased preload) = decreased cardiac output =heart attack/ myocardial rupture

hematochezia

bloody stool associated with diverticulitis (lower GI bleed)

hemorrhage

escape of blood from the cardiovascular system. can escape: 1) on the floor 2) into subcutaneous tissues and organs 3) into body cavities --> pleural cavity= hemothorax --> peritoneal cavity= hemoperitoneum --> pericardial cavity = hemopericardium --> joint cavity = hemarthrosis

Process of hemorrhage resolution

fresh blood / hemorrhage appears purple. it will appear red when it starts to resolve, and will appear yellow when it's in the middle of resoltion

hemarthrosis

leaking of blood into the joint cavity

hemopericardium

leaking of blood into the pericardial cavity

hemoperitoneum

leaking of blood into the peritoneal cavity (abdomen)

hemothorax

leaking of blood into the pleural cavity

thrombocytopenia

low platelet counts due to the megakaryocytes getting wiped out in the bone marrow. this is usually occurring with petechiae

anemia of chronic blood loss

low rate of bleeding over a long period of time, such as from chronic menstruation or from a gastric bleed. This rate of bleeding will exceed the bone marrow's capability of replenishing blood, so you will have a lower red blood cell count. -one of the systemic effects of hemorrhage.

hypovolemic shock

occurs due to hemorrhage, where you lose a massive amount of blood volume and get systemic hypotension

hematoma

pool of blood within a tissue (large) -subcutaneous hematomas are NOT flat- they're raised. -usually occurs secondary to trauma -size is determined by the severity of the trauma

exsanguination

process of blood loss leading to death (bleed out and die) -one of the systemic effects of hemorrhage

hypovolemic

process where your body is not getting enough blood flow due to a massive loss of blood volume in the intravascular areas -one of the systemic effects of hemorrhage

purpura and what it's associated with

slightly larger hemorrhages than petechiae (3-10 mm) usually associated with A) locally increased intravascular pressures B) low platelet counts (thrombocytopenia) C) defective platelet function D** additional: secondary to trauma E**additional: secondary to inflammation involving vessels- vasculitis

neurogenic shock

spinal cord injury causing you to lose SNS tone that normally functions to cause unconscious vasoconstriction. if you lose this SNS tone you get vasodilation= neurogenic hypotension

shock

systemic hypotension (low blood pressure) --> leads to deficient blood flow in the peripheral vascular bed --> tissue hypoperfusion and hypoxia therefore end organ ischemic damage.

anaphylactic shock

systemic hypotension due to allergic reactions, where you release histamine, which causes vasodilation

septic shock

systemic hypotension due to diffuse infections

melena

tar-like black stools associated with an upper GI bleed (esophageal varices, gastric ulcer)

How is the severity of a hemorrhage assessed?

the clinical significance of hemorrhage depends on the volume, rate, and site of hemorrhage. obviously if you bleed out quickly, it causes more of a problem. for example: massive bleeding (i.e from esophageal varices) can lead to hypovolemic shock (massive loss of blood volume= diminished cardiac output) for example: usually small bleeds are not a big deal but in the brain they are critical because of the "unyielding" skull.

why does a small hemorrhage in the brain cause a problem?

the skull is "unyielding"- bleeding in the brain can cause large increases in intracranial pressure, which can lead to brainstem herniation.

hemosiderin vs. hematoidin

these both appear around macrophages histologically. hemosiderin contains iron and appears when macrophages are eating red blood cells (byproduct of hemoglobin) hematoidin appears yellow, doesn't contain iron, and resembles billirubin