PATH 3810 Pathology of the Cardiovascular System

edema

increased fluid in interstitial space

anasarca

severe and generalized edema with profound subcytaneous tissue swelling

edema of submucosal intestinal tissue

ascites

ascites / hydroperitoneum

edema of the peritoneal cavity

pulmonary edema (bottom) vs normal lung tissue (top)

increased hydrostatic pressure

• impaired venous return

• arteriolar dilation

• category of edema

reduced plasma osmotic pressure (hypoproteinemia)

• loss of albumin

• category of edema

albumin

serum protein most responsible for maintaining intravascular osmotic pressure

lymphatic obstruction

• lymphedema

• usually localized

  • category of edema

sodium water retention

• increased salt draws in water and increases hydrostatic pressure

• increased renal tubular reabsorption of sodium

  • category of edema

hyperemia

active process resulting from augmented blood flow due to arteriolar dilation

congestion

passive process resulting from impaired venous return out of tissue

chronic passive congestion of the liver (gross)

chronic passive congestion of the liver (microscopic)

hemorrhage

extravasation of blood from vessels into extracellular space

hemorrhage can be…

…external or confined within a tissue

hematoma

hemorrhage confined within a tissue

petechiae

minute (1-2mm) hemorrhages into the epithelium/underlying tissue

purpura

medium (3-5mm) hemorrhages

ecchymoses

large (1-2cm) subcutaneous hematomas

large accumulation of blood in body cavities

• hemothorax

• hemopericardium

• hemoperitoneum

• hemarthrosis

petechiae

intracranial hemorrhage

epicardial hemorrhage

ecchymoses

hemorrhage of the leg

gastric hemorrhage

thrombosis

pathologic form of hemostasis

thrombus formation in uninjured vessels or thrombotic occlusion of a vessel after minor injury

three principal influences on thrombus formation

• endothelial injury

• abnormal blood flow

• hypercoagulability

arterial or cardiac thrombi begin at…

…sites of endothelial injury or turbulence

venous thrombi begin at…

…sites of stasis

thrombi are…

…focally attached to the underlying vascular surface and tend to propagate toward the heart

embolus

a mass that is carried by bloodstream to a place distant from point of origin

can be:

• broken, free fragment of thrombus (thromboembolism)

• solid, liquid, or gaseous mass

• fat droplets, air droplets, atherosclerotic debris

vegetations

thrombi on heart valves

arterial thrombus (gross)

arterial thrombus (microscopic)

venous thrombus

white/pale infarct of the kidney

red/hemorrhagic infarct of the kidney

red infarct of the lung

pale infarct of the spleen

thrombosis outcomes

1. propagation

2. embolization

3. dissolution

4. organization/recanalization

pulmonary thromboembolism

95% of cases are a venous embolus from deep leg vein thrombus

saddle thrombus in pulmonary artery

systemic thromboembolism

embolism in the arterial circulation

80% arise from intracardial mural thrombi, particularly left ventricular wall infarcts

major sites of embolism are lower extremities and brain

air embolism

may occur during chest wall injury or decompression sickness

amniotic fluid embolism

complication of labor

caused by entry of amniotic fluid into the maternal circulation via tear in the placental membranes and rupture of uterine veins

fat embolism

fat globules may enter bloodstream after long bone fracture or soft tissue trauma

occlude pulmonary and cerebral microvasculature

fat embolus from bone marrow

shock

final common pathway for a number of potentially lethal events

gives rise to systemic hypoperfusion

• hypotension, hypoxia, hypoperfusion

cardiogenic shock

results from heart failure

• myocardial infarction

• ventricular arrythmias

• outflow obstruction

hypovolemic shock

results from loss of blood or plasma volume

• hemorrhage

• extensive burns

septic shock

results from microbial infection

• lipid A released by Gram-negative bacteria

neurogenic shock

results from a loss of vascular tone leading to peropheral blood pooling

anaphylactic shock

results from systemic vasodilation and increased vascular permeability mediated by IgE: type I hypersensitivity reaction

shock is characterized by…

…multisystem organ failure due to hypoxic injury

clinical triad of septic shock

• hypotension

• disseminated intravascular coagulation

• metabolic disturbances

blood pressure is a function of…

…cardiac output, peripheral resistance, and hormonal regulation

hypertensive vascular disease

chronic hypertension causes damage to arterioles and endothelium

arteriosclerosis

hyaline arteriosclerosis

hyperplastic arteriosclerosis

atherosclerosis

characterized by intimal lesions called atheromas that protrude into vascular lumina and obstruct blood flow

atheroma

raised lesion with a soft yellow grumous core of cholesterol and covered by a firm white fibrous cap

atherosclerosis (gross)

atherosclerosis (gross)

atherosclerosis (microscopic)

aneurysm

localized abnormal dilation of a blood vessel or the heart

true aneurysm

involves all three layers of arterial wall

false aneurysm

breach in the vascular wall leading to extravascular hematoma

dissection

blood enters the wall of the artery as a hematoma separating its layers

aortic aneurysm

aortic dissection

blood separates the laminar planes of the media to form a blood-filled channel within the aortic wall

often secondary to hypertension

pulmonary artery dissection

cystic medial degeneration

loss of smooth muscle cells, fragmentation or mineralization of elastic fibers

predisposes artery to aneurysm or dissection

cystic medial degeneration

medial dissection

immune-mediated vasculitis

type III hypersensitivity, associated with AgAb complexes

polyarteritis nodosa

systemic

inflammation of small to medium muscular arteries

causes restriction of blood flow

polyarteritis nodosa (gross)

polyarteritis nodosa (microscopic)

shunt

abnormal connection between heart chambers or blood vessels

obstructive congenital heart disease

developmental heart abnormalities that obstruct vascular flow by narrowing of chambers, valves, or major vessels

atresia

complete obstruction of a normal opening

left to right shunt

septal defects & patent ductus arteriosus

atrial septal defects

failure of closure of foramen ovale after birth

patent ductus arteriosus

failure of closure of ductus arteriosus, which allows blood flow from aorta to pulmonary artery

ventricular septal defect: left to right shunt

tetralogy of Fallot

• right to left shunt

• includes ventricular septal defects, obstruction to right ventricular outflow tract, aorta that overrides the VSD, and right ventricular hypertrophy

congestive heart failure

heart is no longer able to pump blood at rates required for tissues

forward failure of the heart

inadequate cardiac output

backward failure of the heart

increased congestion of venous circulation

left-sided heart failure common causes

• systemic hypertension

• ischemic heart disease

• mitral or aortic valve disease

• myocardial disease

myocardial infarction (gross)

necrotic stage of myocardial infarction

acute inflammatory stage of myocardial infarction

subacute inflammatory stage of myocardial infarction

fibrosis stage of myocardial infarction

left-sided heart failure morphology

hypertrophy, dilation, fibrosis, atrial thrombi, cardiomegaly

pulmonary congestion, edema, dyspnea, tachycardia, murmur (third heart sound), fine rales

left-sided heart failure