2 - Hemodynamic Disorders, Thrombosis, and Shock Flashcards
Blood from hemorrhage may accumulate in body cavities. What is the specialized term for accumulation of blood in the pleural cavities?
Hemothorax
Describe the gross appearance (colour) of edema fluid.
Clear to slightly yellow
Is edema fluid a transudate or an exudate?
Transudate (low protein content)
Describe the gross appearance of lungs affected by chronic congestion due to heart failure.
The lungs are moderately FIRM and YELLOW-BROWN to TAN. [The tan colour is because of alveolar macrophages containing hemosiderin from alveolar hemorrhage. Inflammatory mediators produced by these macrophages also induce fibroplasia, thus there is extensive formation of interstitial collagen in the long term. This collagen is the reason the lungs fail to collapse after loss of negative pressure in the pleural cavity when the diaphragm is incised at necropsy.]
What is the pathogenesis whereby malnutrition may lead to generalized edema?
Malnutrition -> inadequate uptake of protein substrates from gut -> insufficient protein substrates (amino acids) available for liver to be able to synthesize albumin -> reduced hepatic synthesis of albumin -> reduced levels of plasma proteins -> reduced intravascular osmotic pressure -> generalized edema
Arrange the following hemorrhages by size, from largest to smallest:
(a) Ecchymosis
(b) Petechiae
(c) Purpura
(d) Suffusive
(d) Suffusive > (a) Ecchymosis > (c) Purpura > (b) Petechiae
List the four basic, underlying mechanisms that result in edema.
- Increased hydrostatic pressure; 2. Decreased intravascular osmotic pressure; 3. Decreased lymphatic drainage; 4. Increased vascular permeability
What is the basic underlying reason for the reduced intravascular osmotic pressure that may result in edema?
Decreased plasma proteins (more specifically, albumin) in circulation
What is the pathogenesis whereby severe intestinal parasitism may lead to generalized edema?
Intestinal parasitism -> ingestion of blood, including plasma proteins, by parasites -> reduced levels of plasma proteins (beyond liver’s ability to regenerate them quickly enough) -> reduced intravascular osmotic pressure -> generalized edema
Of the following 4 factors that can influence development of edema, which may be DECREASED when edema develops?
(a) Hydrostatic pressure
(b) Intravascular osmotic pressure
(c) Lymphatic drainage
(d) Vascular permeability
(b) Intravascular osmotic pressure and (c) lymphatic drainage
Blood from hemorrhage may accumulate in body cavities. What is the specialized term for accumulation of blood in a joint?
Hemarthrosis
What is the pathogenesis by which internal breakdown of red blood cells (e.g., caused by hemolysis or hemoabdomen) leads to icterus?
Blood breakdown -> massive release of bilirubin -> overwhelms liver’s ability to process it -> accumulates in tissues, most noticeably in lightly pigmented tissues such as sclera, fat and skin -> icterus (= jaundice)
What is a typical underlying cause for GENERALIZED edema resulting from increased intravascular hydrostatic pressure?
Heart failure, which causes passive accumulation of blood (congestion)
Blood from hemorrhage may accumulate in body cavities. What is the specialized term for accumulation of blood in the cavity around the heart?
Hemopericardium
What is the primary driving force creating intravascular osmotic pressure?
The presence of plasma proteins
What is the underlying reason for reduced lymphatic drainage of a site, and what are two possible causes of this?
Underlying reason: blockage or compression of lymphatic vessels. Possible causes include: (a) Compression by tumors or nearby inflammatory swelling; (b) Blockage by lymphatic vessel inflammation & fibrosis, by tumors or by clots.
Give two possible (common) reasons why a liver might have acute passive congestion at necropsy.
(1) Sudden heart failure resulting from arrhythmias; (2) Euthanasia. [Acute passive congestion occurs in the vascular system and dependent organs (heart, lungs, portal system) when there is a sudden interruption of the return of blood to the heart, as occurs in heart failure resulting from arrhythmias and after euthanasia.]
Which term(s) mean(s) increased volume of blood at a particular anatomic location?
(a) Ascites
(b) Congestion
(c) Hyperemia
(d) Icterus
(e) Infarction
(b) Congestion and (c) hyperemia
Where does all lymphatic fluid ultimately end up, and how does it get there?
In the systemic (blood) circulation; it is returned here from the lymphatic system by a major lymphatic duct entering a large vein cranial to the heart (typically into the cranial vena cava)
What is the term used for hemorrhages that are greater than 1 to 2 cm in diameter?
Ecchymoses (or ecchymotic hemorrhages)
What are the three fluid compartments in the body? That is, where can INTERNAL fluids (i.e., not in the bladder, stomach etc.) be located?
Intravascular; Interstitial (Intercellular); Intracellular
How are ascites and hydrothorax different?
Ascites means fluid (edema) accumulation in the peritoneal cavity; hydrothorax means fluid accumulation in the pleural cavities
What is the pathogenesis whereby liver disease may lead to generalized edema?
Liver disease -> reduced hepatic synthesis of albumin -> reduced levels of plasma proteins -> reduced intravascular osmotic pressure -> generalized edema
What is the pathogenesis of the edema that develops at sites of inflammation?
Inflammation (localized or generalized) -> release of vasoactive inflammatory mediators -> endothelial cell contraction -> widening of interendothelial gaps -> increased vessel permeability -> fluid leakage to interstitium -> edema
What are two terms for edema fluid accumulation in the peritoneal cavity?
Ascites and hydroperitoneum
Using a subcutaneous hematoma (bruise or contusion) as an example, list the characteristic progression of color changes that occur over time as the hematoma resolves, AND the pigment responsible for each different colour.
From earliest to latest:
(a) Red-blue (hemoglobin)
(b) Blue-green (bilirubin & bilverdin)
(c) Golden brown (hemosiderin)
What is the term for the type of subcutaneous edema where pushing the skin with a finger leaves an indentation that is slow to resolve?
Pitting edema
What term refers to increased blood at an anatomic location resulting from arteriolar dilation?
Hyperemia
Extensive hemopericardium can interfere with dilation and contraction of the heart, causing heart failure. What is the term for this process?
Cardiac tamponade. [Any fluid in the pericardial sac can lead to this, but blood is most commonly the culprit because it tends to accumulate rapidly, before the pericardial sac can stretch in compensation.]
What is the term for a tendency to hemorrhage from insignificant injury?
Hemorrhagic diathesis
What is the term used for hemorrhages that are 1 to 2 mm in diameter?
Petechiae (or petechial hemorrhages)
Describe the gross appearance of a liver affected by chronic congestion due to heart failure.
The liver is ENLARGED, FIRM and has ROUNDED MARGINS.
What does the term edema mean?
An accumulation of excess fluid in either the interstitial space or the body cavities
What is a typical underlying cause for LOCALIZED edema resulting from increased intravascular hydrostatic pressure?
Venous obstruction or compression, which causes passive accumulation of blood (congestion)
What is the term used for hemorrhages that are 3 to 10 mm in diameter?
Purpura (or purpura hemorrhagica)
What is a hemorrhagic diathesis?
A tendency to hemorrhage from insignificant injury.
What term refers to increased blood at an anatomic location resulting from impaired venous drainage of the site?
Congestion
Of the following 4 factors that can influence development of edema, which may be INCREASED when edema develops?
(a) Hydrostatic pressure
(b) Intravascular osmotic pressure
(c) Lymphatic drainage
(d) Vascular permeability
(a) Hydrostatic pressure and (d) vascular permeability
How are ascites and hydroperitoneum different?
They’re not. The two terms are synonymous
What are the TWO basic, underlying mechanisms whereby plasma albumin may be decreased?
(1) REDUCED SYNTHESIS by liver [e.g., malnutrition or intestinal malabsorption of protein reducing amount of substrate liver has; or liver disease]; (2) INCREASED LOSS from various sites [including gut (protein losing enteropathy or severe parasitism), kidney (protein losing nephropathy) or skin (burns)]
What does the term hydrothorax mean?
Fluid (edema) accumulation in the pleural cavities
What force is responsible for fluid leaving the circulation and entering the interstitium in normal, healthy animals?
Hydrostatic pressure
Blood from hemorrhage may accumulate in body cavities. What are TWO specialized terms for accumulation of blood in the peritoneal cavity?
Hemoabdomen; Hemoperitoneum
What does the term ascites mean?
Fluid (edema) accumulation in the peritoneal cavity
Explain the fundamental difference between hyperemia and congestion.
In hyperemia there is increased inflow of blood because of arteriolar dilation, leading to engorgement with oxygenated blood. In congestion, diminished outflow leads to a capillary bed swollen with deoxygenated venous blood, resulting in cyanosis.
What does the term hematoma mean?
Internal hemorrhage into soft tissues rather than into body cavities. This could include the skin, muscle, subcutis or brain.
Which of the following best describes the gross appearance of pulmonary edema?
(a) The lungs are heavy, wet, glistening and ooze fluid when squeezed
(b) Pushing the lung with a finger leaves an indentation that is slow to resolve
(c) The lungs are markedly enlarged and gelatinous
(d) The pleural cavities contain abundant clear-yellow fluid that compress the lungs
(a) The lungs are heavy, wet, glistening and ooze fluid when squeezed
Match a letter to a number, below:
(a) Congestion
(b) Hyperemia
(1) Diminished inflow of blood
(2) Diminished outflow of blood
(a)-(2)
Blood from hemorrhage may accumulate in body cavities. Give five specialized terms for this and define each one. [Hematoma is not one of the answers.]
(1) Hemothorax: in pleural spaces; (2) Hemoperitoneum: in peritoneal cavity; (3) Hemoabdomen: in peritoneal cavity (same as hemoperitoneum); (4) Hemopericardium: in pericardial space; (5) Hemarthrosis; in synovial cavity of joint
Describe the gross appearance of edema where fluid accumulates in the interstitium, rather than in a body cavity.
The organ is enlarged and may be gelatinous (especially if present in the intestinal wall). Subcutaneous tissues may be doughy, fluctuant and cool to the touch.
What is the term for an accumulation of excess fluid in either the interstitial space or the body cavities?
Edema
What does the term hydroperitoneum mean?
Fluid (edema) accumulation in the peritoneal cavity
What is the term used for hemorrhages that cover large contiguous areas?
Suffusive hemorrhage
What force is responsible for fluid moving from the interstitium to the circulatory system in normal, healthy animals?
Intravascular osmotic pressure
What is the pathogenesis whereby kidney disease may lead to generalized edema?
Renal disease -> defective (“leaky”) glomerular filtration barrier -> loss of plasma proteins into urine -> reduced levels of plasma proteins (beyond liver’s ability to regenerate them quickly enough) -> reduced intravascular osmotic pressure -> generalized edema
Which two organs most commonly show gross and histologic lesions associated with CHRONIC congestion caused by heart failure?
Lungs and liver
Describe the gross appearance of a lung affected by pulmonary edema.
The lungs are heavy, wet, glistening and ooze fluid when squeezed
