Pathophysiology of Edema and Infarcts

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Questions and Answers

What is the primary cause of pulmonary edema?

Inflammation

Lymphatic obstruction

Congestive Heart Failure (correct)

Nephrotic Syndrome

Which type of edema is characterized by increased hydrostatic pressure?

Pitting edema (correct)

Non-pitting edema

Ascites

Lymph-edema

Which of the following conditions is most likely to lead to facial edema as a primary manifestation?

Pulmonary hypertension

Congestive heart failure

Nephrotic Syndrome (correct)

Vascular obstruction

What condition can cause localized lymphedema due to impaired lymphatic drainage?

Elephantiasis Signup and view all the answers

What is the result of nephrotic syndrome affecting the Renin-angiotensin-Aldosterone axis?

Salt & water retention Signup and view all the answers

What is primarily responsible for the majority of infarcts in the body?

Arterial thrombotic or embolic events Signup and view all the answers

Which of the following describes an anemic infarct?

Pale and often occurs in solid organs with single blood supply Signup and view all the answers

What is the typical morphology of a hemorrhagic infarct?

Red, soft, and occurs in organs with dual blood supply Signup and view all the answers

Which mechanism can occasionally lead to infarction due to a single efferent vein?

Venous thrombosis Signup and view all the answers

What is the effect of healing on hemorrhagic infarcts?

They transform into fibrous tissue Signup and view all the answers

Which type of shock is characterized by systemic vasodilation and increased vascular permeability mediated by IgE?

Anaphylactic shock Signup and view all the answers

What condition is NOT a cause of hypovolemic shock?

Cardiac tamponade Signup and view all the answers

In septic shock, what is one of the main physiological responses that occurs due to overwhelming infection?

Disseminated intravascular coagulation (DIC) Signup and view all the answers

Which stage of shock involves reflex compensatory mechanisms being activated while maintaining vital organ perfusion?

Non-progressive stage Signup and view all the answers

Which of the following is NOT a characteristic of cardiogenic shock?

Ventilatory failure Signup and view all the answers

What primarily forms a red thrombus?

Blood clot and red blood cells Signup and view all the answers

What characterizes a mixed thrombus?

Lines of Zahn and blood clots Signup and view all the answers

Which type of thrombus contains microorganisms?

Septic thrombus Signup and view all the answers

What process occurs when a thrombus enlarges?

Propagation Signup and view all the answers

Which of the following is true about the dissolution of a thrombus?

Once thrombi fully polymerize, they cannot be dissolved Signup and view all the answers

Which type of embolus is most commonly formed from a thrombus?

Solid embolus Signup and view all the answers

What is the primary feature of lines of Zahn?

Alternating layers of platelets and fibrin with dark red blood cells Signup and view all the answers

What can trigger a gas embolism?

Surgery or decompression sickness Signup and view all the answers

What type of necrosis is most commonly associated with infarcts in tissues other than the CNS?

Coagulative necrosis Signup and view all the answers

Which tissue type is most vulnerable to hypoxia, suffering damage in just 3-4 minutes?

Neurons Signup and view all the answers

What is the primary difference between hyperemia and congestion?

Hyperemia is a result of arteriolar dilation; congestion is due to impaired outflow. Signup and view all the answers

What microscopic finding is typically associated with alveolar macrophages in chronic passive congestion of the lung?

Hemosiderin Signup and view all the answers

Which of the following factors is NOT associated with the development of infarcts?

Presence of inflammation Signup and view all the answers

What primarily characterizes generalized edema?

Excess fluid accumulation in the entire body Signup and view all the answers

What type of infarct is characterized by the presence of necrotic tissue and hemorrhage, typically found in the lungs?

Red infarct Signup and view all the answers

Which of the following is a common cause of hemorrhage due to rupture of blood vessels?

Vascular diseases like aneurysms Signup and view all the answers

Which of the following is NOT a type of edema?

Hypotensive edema Signup and view all the answers

Which of the following describes chronic passive congestion of the liver characterized by a nutmeg appearance?

Congestive heart failure Signup and view all the answers

What is a common cause of reduced plasma osmotic pressure leading to edema?

Nephrotic syndrome Signup and view all the answers

Which condition can lead to increased hydrostatic pressure that contributes to edema?

Congestive heart failure Signup and view all the answers

Inflammation can contribute to edema primarily by increasing what?

Capillary permeability Signup and view all the answers

Which term describes the accumulation of fluid specifically in the peritoneal cavity?

Ascites Signup and view all the answers

Which of the following is a common cause of lymphatic obstruction leading to edema?

Tumor growth Signup and view all the answers

Dependent edema is typically observed in which of the following conditions?

Heart failure Signup and view all the answers

What role does sodium retention play in the development of edema?

Increases fluid retention Signup and view all the answers

What effect does albumin deficiency have on fluid dynamics in the body?

Promotes fluid accumulation in tissues Signup and view all the answers

Study Notes

Hemodynamic Disorders

These disorders involve disturbances in blood flow and volume.
Key components include edema, thrombosis, embolism, infarction, hyperemia, congestion, hemorrhage, and shock.

Edema

Definition: Excess fluid accumulation within extracellular or intracellular spaces.
Types
- Localized: Fluid buildup in a specific organ or body part (e.g., lung edema, ascites).
- Generalized: Fluid buildup throughout the body (e.g., anasarca).
- Special Types: Pulmonary and cerebral edema.

Water

60% of the body is water.
Two-thirds of body water is intracellular.
The rest is interstitial.
Only 5% is intravascular.
Edema involves a shift of fluid to the interstitial space.
Conditions associated with edema: Hydrothorax, pericardial effusions, ascites, and anasarca.

Edema Pathogenesis

Causes: Increased hydrostatic pressure, decreased osmotic pressure, lymphatic obstruction, and sodium retention.
Increased hydrostatic pressure
- Impaired venous return
- Congestive heart failure
- Venous obstruction or compression
- External pressure (e.g., mass)
- Prolonged lower extremity inactivity
Decreased osmotic pressure
- Protein-losing nephropathies (e.g., nephrotic syndrome)
- Liver cirrhosis
- Malnutrition
- Malabsorption
Lymphatic obstruction (lymphedema)
- Inflammatory
- Neoplastic
- Postsurgical (e.g., breast cancer)
Sodium retention: Renal hypoperfusion leading to increased renin-angiotensin-aldosterone secretion.
Inflammation leads to increased capillary permeability
- Acute inflammation results in edema formation in areas of increased vascular permeability

Thrombosis

Definition: Formation of a solid mass of blood elements within a blood vessel or cardiac chamber in a living body.
- Platelets + Fibrin + RBCs
Example: Coronary Thrombus
Hemostasis: The normal, rapid formation of a localized "plug" at the site of vascular injury.
Thrombosis: Abnormal activation of the normal hemostatic process. Also referred to as Pathologic.
Virchow's Triad factors
- Endothelial injury
- Stasis or turbulence of blood flow
- Blood hypercoagulability
  - Primary (congenital)
  - Secondary (acquired, e.g., by weight etc. )

Thrombosis Composition and Location

Thrombi are composed of fibrin, platelets, and red blood cells (RBCs).
Thrombi can form in arteries, veins, heart chambers, and heart valves.

Fate of the Thrombus

Propagation: Thrombus enlarges by additional platelets and fibrin.
Embolization: Part of the thrombus dislodges and travels to different parts of the body.
Dissolution: Newly formed thrombi may be dissolved by fibrinolytic factors. Older ones, however, are more resistant.
Organization and recanalization: The thrombus is remodeled and the blood vessel is re-opened.

Embolism

Definition: An embolus is an insoluble solid, liquid, or gaseous mass circulating in the blood to a site distant from its origin.
Types of Emboli
- Gas (e.g., during surgery)
- Liquid (e.g., amniotic fluid)
- Solid (e.g., thrombus, atheroma).
- Other materials, such as bone marrow or foreign bodies.
Origins and Sites of Embolisation
- Venous: Deep vein thrombosis (DVT) to pulmonary arteries
- Arterial: Heart or aorta to systemic circulation
- Paradoxical: Systemic venous to systemic arterial circulation (via septal defect)

Infarction

Definition: Infarction is the formation of an infarct, a localized area of ischemic necrosis caused by occlusion of the (mostly arterial) blood supply.
85-90% of all infarcts are due to arterial thrombotic or embolic events.
Other less common causes include vasospasm, expansion of atheroma, hemorrhage, external compression, traumatic vascular ruptures, and vessel twisting.
Microvascular causes:
- Vasospasm
- expansion of atheroma
- Hemorrhage
- External compression
- Traumatic vascular rupture
- Vessel twisting
Types of infarction
- Pale: often wedge-shaped, in solid organs with a single blood supply (Kidneys, Spleen, Heart).
- Hemorrhagic: In organs with dual or collateral blood supplies (Lungs, bowel, liver).

Hyperemia and Congestion

Hyperemia: Increased blood flow to a tissue due to arteriolar dilation (active process, e.g., active inflammation).
Congestion: Impaired outflow leading to increased blood volume in a tissue (passive process, e.g., heart failure).
Chronic Passive Congestion (Lung): Heart failure leads to alveolar macrophages containing hemosiderin.
Chronic passive congestion (Liver): “Nutmeg” liver.

Hemorrhage

Definition: Extravasation of blood due to rupture of blood vessels.
AE
- Rupture of large vessel: trauma, atherosclerosis, inflammatory or neoplastic erosion
- Rupture of small vessel: hemorrhagic diathesis
Causes
- Vascular diseases with rupture (e.g., atherosclerosis, arteritis, aneurysms)
- Low platelet count (<10,000-15,000/cu mm)
- Coagulopathy (coagulation factors <10% activity)
- Ulcers, tumors, coagulation factor abnormalities, trauma
Types of hemorrhage
- External
- Internal (cavity)
- Tissue
- Petechiae
- Purpura
- Ecchymoses
- Hematoma
- Hemoptysis
- Hematemesis
- Melena
- Hematochezia
- Hematuria
- Hemopericardium
- Hemmothorax
- Hemoperitoneum

Shock

Definition: Systemic hypoperfusion due to a reduction in cardiac output.
Types of shock
- Cardiogenic
- Hypovolemic
- Neurogenic
- Septic
- Anaphylactic
Stages of shock
- Non-progressive
- Progressive
- Irreversible

Studying That Suits You

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Description

Test your knowledge on the causes and types of edema, including pulmonary and facial edema, and explore the mechanisms of infarcts. This quiz will help you understand the physiological responses related to shock conditions and the effects on tissue morphology.