Learning Unit 4 - Pathology

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Edema

1. An excess accumulation of fluid in the interstitial tissue spaces. 2. May be either localized, such as in inflammation, or generalized, as in cardiac failure. 3. It is extravascular (outside the vessels)
4. Results from escape of excess amounts of fluid or from its inability to return to the blood

Causes of Edema

1. Increased permeability of capillary walls - in injury, plasma escapes into tissues spaces causing edema. 2. Increased capillary pressure due to venous obstruction or heart failure - blood pressure is increased and fluid remains in the tissues. 3. Inflammatory conditions. 4. Fluid and electrolyte disturbances

Examples of Edema

1. Anasarca / Dropsy 2. Ascites 3. Hydrothorax or Pleural effusion 4. Hydropericardium or pericardial effusion

Anasarca / Dropsy

Severe generalized massive edema

Ascites

Excess fluid in the peritoneal (abdominal) cavity.

Hydrothorax / Pleural effusion

Excess fluid in the pleural cavity.

Hydropericardium / Pericardial effusion

Excess fluid in the pericardial cavity.

Hyperemia / Congestion

1. An excess amount of blood in a body part or area 2. Due to an increased arterial supply to the part or to a decrease in venous return 3. Two types (Active / Arterial, Passive / Venous)

Active / Arterial Hyperemia

1. Hyperemia as a result of an increase in the arterial flow to a body part. 2. Two Types (Physiological, Pathological)

Active / Arterial Physiological Hyperemia

Results from increased arterial flow for natural reasons, such as in blushing, where no lesion exists. Presence of extra blood in the muscles of the body during exercise.

Active / Arterial Pathological Hyperemia

Results from increased arterial flow
as a bodily reaction to injury, such as in inflammation.

Passive / Venous Hyperemia

1. Hyperemia as the result of a decrease in the venous drainage from a body part. 2. Passive hyperemia will always be a pathological condition 3. Two types (Local Passive, Generalized)

Local Passive / Venous Hyperemia

1. Caused by a obstruction of a vein due to a thrombus, embolus, thickening of the vessel walls or external pressure. 2. The affected area will appear swollen, cool to the touch,and will be dark reddish-blue in color.

Generalized Passive / Venous Hyperemia

1. Caused by an obstruction of blood flow through the heart, leading to inadequate circulation. 2. The results of this are known as hypostatic congestion (the settling of the blood to dependent regions).

Hypostatic Congestion

The settling of blood to dependent regions

Ischemia

1. A decrease in the arterial blood flow or supply to a given part of the body 2. A prolonged ischemic condition can lead to localized necrosis, known as an infarction or ischemic necrosis.

Infarction

1. Localized Necrosis 2. Also called Ischemic Necrosis

Causes of Ischemia

1. Blood Clot 2. Hypotension 3. Changes in blood vessels (Ex. Atherosclerosis- a thickening in the vascular walls)

Thrombus / Embolus

Blood Clot, Solid Mass within the heart of vessels of the body.

Hypotension

Decreased Blood Pressure

Atherosclerosis

A thickening in the vascular walls

Effects of Ischemia

1. Decrease in blood flow to the tissues. 2. Decrease nutrients. 3. May cause death of tissue (necrosis) which may be irreversible

Thrombosis

1. Refers to the formation of a solid mass, or blood clot within the heart or vessels of the body.
2. The mass itself is called the thrombus.

Causes of Thrombosis

1. Injury to a blood vessels - the inner lining (tunica intima) of a vessel is normally a very smooth, slick lining of endothelium. Rough spots on this lining will give rise to the formation of clots.
2. Reduced rate of blood flow - blood does not normally remain stagnant for any length of time,
as it is always on the move. Slowing of blood will predispose blood to clotting. 3. Alterations in blood composition - the blood may become thicker thereby predisposing to clots. 4. Blood diseases - some blood diseases will have an increase in the number of red blood cells or
platelets increasing its viscosity and clotting ability.

Locations of Thrombi

1. Arteries 2. Veins (Especially the legs) 3. Heart
4. Aorta

Obstructive Thrombus

The entire lumen is occluded

Parietal Thrombus

The lumen is partially occluded

Changes in Thrombi

1. Embolize 2. Propagate 3. Dissolution 4. Organization 5. Recanalization

Embolize

Thrombus breaks off or dislodges and travels to different sites in the blood vascular system

Propogate

a small thrombi can extend down the long axis of the vessel, increasing in thickness until the vessel is totally occluded

Dissolution

Enzymes specific for this purpose (fibrinolytic proteins) engulf and dissolve the clot

Organization

A conversion of the thrombus into a fibrous plug

Recanalization

Channels start to develop within the fibrous plug restoring partial blood flow.

Consequences of Thrombi

1. Ischemia - is a decrease in blood flow to an area resulting from the blockage (obstruction) in the vascular system 2. Passive hyperemia (congestion) - if the thrombus is in a vein, blood will back up causing congestion (hyperemia)
3. Gangrene 4. Infarction - necrosis (death) of tissue due to decrease in blood supply 5. Emboli /embolus - if a piece of thrombi breaks off and circulates in the blood stream
(thromboembolus)

Embolism

1. Is the condition of a solid, liquid or gaseous mass carried in the blood stream until it becomes lodged somewhere else in the circulatory system
2. The mass itself is called the emboli or embolus

Emboli / Embolus

A solid, liquid or gaseous mass carried in the blood stream

Types of Emboli / Embolus

1. Fragments of thrombi 2. Septic emboli 3. Tumor cells 4. Animal parasites 5. Fat embolism 6. Air or gas 7. Foreign bodies

Fragments of thrombi

The most common type of Emboli / Embolus

Septic Emboli

1. Type of Emboli / Embolus 2. Occurs in bacterial endocarditis and when bacterial colonies either are growing inveins or gain access to the circulation

Tumor Cells

1. Type of Emboli / Embolus 2. Malignant tumors; __________may become detached and enter circulation and then
carried to the lungs or other organs. 2. It is by this means that cancer is spread throughout the body

Animal Parasites

1. Type of Emboli / Embolus 2. Numerous parasitic worms find their way into the blood stream

Fat Embolism

1. Type of Emboli / Embolus 2. Results from severe trauma or crushing injuries to bone which allows the fat in the bone marrow to enter the veins in form of fat globules.

Air / Gas

1. Type of Emboli / Embolus 2. Due to the entrance of air into the veins either during surgical procedure or through hypodermic injections.

Foreign Particles

1. Type of Emboli / Embolus 2. Such as dirt or even pellets from a shotgun blast can enter the vessels and become an emboli

Consequences of Emboli / Embolus

1. Ischemia - reduction of blood flow resulting in lack of oxygen and nutrients to the tissue 2. Infarction or ischemic necrosis - as a result of ischemia, the area of tissue which was deprived
of its blood supply dies. 3. Spread of infection - infectious emboli may result in system infection 4. Spread of tumor cells - tumor cells may travel to distant sites and cause metastatic tumor growth 5. Necrosis - death of the tissue

Infarct

Area of tissue that has died

Hemorrhage

1. The escape of blood from the blood vascular system. 2. Anytime that blood leaves
of vessel, it can be described as _____________.

Causes of Hemorrhage

1. Trauma - injury to blood vessels or soft tissue resulting in bleeding 2. Vascular disease - increased vascular fragility (i.e. infections, drug reactions, poor vascular support) 3. Blood disorder that increases the tendency to bleed - disorders of platelets (thrombocytopenia)
or defects in clotting factors (coagulation) hemophilia 4. Hypertension - elevated blood pressure resulting in disruption of the blood vessel wall (i.e. hemorrhagic stroke)

Hemophelia

Defect in clotting factors (coagulation)

Thrombocytopenia

Disorder of platelets; Increases the tendency to bleed

Hypertension

Elevated blood pressure

Petechiae

Small pinpoint hemorrhages found in the skin, mucous membranes or eye sclera (white portion)(small purpura).

Purpura

Purple colored spots and patches that occur on the skin , on organs, and membranes including the lining of the mouth

Ecchymosis / Bruise

1. A purple or bluish area on the skin or mucous membrane caused by extra-vasation of blood into the subcutaneous tissue. 2. Often due to trauma to the blood vessel or fragility of the blood vessel. 3. A large purpura

Hematoma

1. A localized collection of extravascular blood; a circumscribed tumor-like swelling filled
with blood. 2. A space occupying a collection of blood. (On a small scale, when you hit yourself with a hammer, you get a hematoma or a blood blister)

Epistaxis / Nose Bleed

Hemorrhage from the nose.

Hemoptysis

The presence of blood in the sputum; coughing up blood caused by a hemorrhage in the lungs; or TB.

Hematemesis

The presence of blood in the vomit caused by a hemorrhage in the upper gastrointestinal tract.

Melena / Melenic

1. Black or dark brown, "black tarry stool" sticky intestinal material/feces; 2. Contains digested blood from upper gastrointestinal bleeding 3. Looks like chocolate syrup

Hematuria

Blood in urine caused by: infection; tumor; trauma and kidney stones

Hemothorax

Accumulation of blood in the thoracic cavity

Exsanguination

Excessive loss of blood due to internal or external hemorrhage

Diminished CIrculation

1. A prime concern to the embalmer. 2. Thrombosis, embolisms, tumors and
various other arterial disorders can result in decreased flow of embalming fluids. 3. _______________may even have the effect of causing emaciation and dehydration of various body areas if the blood supply had been lessened for an extended period of time.

Rapid Decomposition

Edema in the tissues predisposes to _________________ in a dead body.

Post-Mortem Conditions Associated with Circulatory Disorders (Concerns for Embalmers)

1. Diminished circulation - embolisms, tumors and various other arterial disorders can result in decreased flow of embalming fluids. Diminished
circulation may even have the effect of causing emaciation and dehydration of various body areas
if the blood supply had been lessened for an extended period of time. 2. Rapid decomposition - edema in the tissues predisposes to rapid decomposition in a dead body. 3. Discoloration - in areas visible during viewing. 4. Hemorrhage - can actually short circuit the flow of embalming fluid through out the body. 5. Abscess - can put pressure on vessels also leading to a decrease in the flow of embalming fluids.

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