Acute Inflammation - SRS Flashcards
What are the three outcomes of acute inflammation?
- It resolves
- Leads to chronic inflammation
- ummm… leads to chronic inflammation
Okay, so I listened to this part a couple of times and it sounded like he said it led to chronic inflammation two of the three possible outcomes. If I missed something here please correct this slide.
What are the five general sequential steps by which the inflammatory reaction develops and subsides?
- Offending agent (in extravascular tissues) is recognized by host cells and molecules
- Leukocytes and plasma proteins are recruited from the circulation to the site where the agent is located.
- Leukocytes and proteins are activated and work together to destroy the offending substance.
- The reaction is controlled and terminated
- The damaged tissue is repaired
1.
What type of necrosis is seen in TB?
How does the body deal with a TB infection?
Caseous necrosis
Since the immune system can’t kill the TB it walls it off from everything, including O2, with granulomatous tissue. This causes a dead area within the walled off section.
(granuloma encases the pathogen - leading to caseous necrosis)
What cell type is primarily associated with acute inflammatory reactions?
Neutrophils
What cell type is mostly associated with chronic inflammation?
Macrophages
Is asthma an acute or chronic inflammatory reaction?
It is both.
What cytokine is responsible for pulmonary fibrosis?
TGF-B
What are the 5 cardinal signs of inflammation?
Calor - Heat
Rubor - Redness
Tomor - Swelling
Dolor - Pain
Functio-laesa - Loss of function
What are the four primary causes of inflammation?
- Infections
- Tissue necrosis (due to Trauma, chemical, thermal injuries)
- Foreign Bodies
- Hypersensitivity (Immune reactions
What causes the inflammatory response seen in celiac disease?
GI flora that get in the lymph system or cause an antigenic change the immune system responds poorly to.
(Also this for Inflammatory Bowel Disease)
What type of necrosis is causing this inflammation?
Coagulative necrosis
What is the source of inflammation in this image?
Foreign body - This is a suture granuloma (refractile tissue surrounded by multinucleated giant cells)
What is this inflammatory response caused by/called?
Urticaria - caused by a hypersensitivity reaction
What are the steps of inflammation?
The five R’s
- Recognition of injurious agent
- recruitment of leukocytes
- removal of agent
- regulation of response
- Resolution (repair)
What are the 3 major components of acute inflammation?
- Dilation of small vessels, leading to increase in blood flow
- Increased permeability of the microvasculature enabling plasma proteins and leukocytes to leave the circulation
- Emigration of the leukocytes from the microcirculation, their accumulation in the focus of injury, and their activation to eliminate the offending agent
In super basic terms what is the process by which leukocytes diapedese?
Stop
Drop
Roll
Characterize the magnitude of hydrostatic pressure vs. colloid osmotic pressure and the net flow of fluid, under normal conditions.
Hydrostatic pressure exceeds colloid osmotic pressure normally, so there is a small net outflow from the vessels. (Per Dr. Hertz)
What causes exudate?
Increased vascular permeability due to increased interendothelial spaces
What are the typical contents of exudate?
- High Protein
- Some white cells
- Some red cells
What causes transudate?
Fluid leakage due to significantly increased hydrostatic pressure or decreased osmotic pressure.
Describe the contents of transudate.
Low protein
Few cells
A two year old girl’s urinalysis detects elevated protein levels. A sample of fluid is taken from the patients edemetous regions. What type of fluid is this?
What is this condition called?
Transudate
Nephrotic Syndrome
In a patient with liver cirrhosis would you see transudate or exudate?
Transudate, due to drop in protein production leading to diminished colloid osmotic pressure
If a patients heart function tanks, will we see exudate or transudate?
Transudate - due to increased hydrostatic pressure in the venous system.
Between transudate and exudate which is benign?
Transudate is benign.
Exudate is bad.
A 52 year old male is delivered unconscious to your ED with bilateral hemothorax and no evidence of trauma. What is the most likely diagnosis?
Hemmorhagic exudate w/o trauma = Cancer - until proven otherwise
How does vascular flow and caliber change during inflammation? (The process, not just the results)
- Histamine and several other mediators cause vasodilation by acting on smooth muscle
- This swiftly leads to increased permeability of microvasculature and the outpouring of protein rich fluid into the extravascular tissues
- The loss of fluid and increased vessel diameter lead to slower blood flow, concentration of RBC’s in small vessels and increased viscocity of blood
- This leads to stasis, allowing blood leukocytes - mostly neutrophils -accumulate along the vacular endothelium
What are the three ways that vascular permeability may be increased?
- Contraction of endothelial cells resulting in increased interendothelial spaces. (most common)
- Endothelial injury, resulting in endothelial cell necrosis and detachment.
- Increased transport of fluids and proteins, called transcytosis, through the endothelial cell.
What is lymphangitis?
Secondary inflammation of lymphatics
What is lymphadenitis?
Inflammation of the lymph nodes
Why are inflamed lymph nodes often enlarged? What is this constellation of changes termed?
Due to hyperplasia of the lymphoid follicles and increased numbers of lymphocytes and macrophages.
This constellation of pathological changes is called reactive, or inflammatory lymphadenitis
What does the presence of red streaks near a wound signify?
Infection in the wound. The streaks follow the lymphatic channels and are diagnostic of lymphangitis.
Lymphangitis may be accompanied by painful swelling of the draining lymph nodes, indicating what?
Lymphadenitis.
He seemed to indicate these lymph questions would be high yield, for boards and possibly our exam.
What is this? Which of the hallmarks of inflammation is visible here?
Lymphadenitis
- Calor
- Dolor
- Tomor
- Rubor
What is this?
Lymphangitis
- The lymph tracts are inflammed and probably infected
- Red streak = time to treat
(This image is going to be on the exam in some capacity)
What causes erythema and stasis of blood flow?
Vasodilation induced by chemical mediators such as histamine
What stops the flow of leukocytes?
Selectins
What hooks the leukocyte to endothelium in preperation for diapedesis?
Integrins
What cells are selectins found on?
Endothelium
What cells have integrins on them?
Leukocytes
What mediates the attachment of leukocytes to endothelium?
complemetary adhesion molecules (selectins and integtins)
After diapedisis, what directs leukocyte movement?
Leukocytes follow cytokines and chemokines through chemotaxis
What organ is this tissue from?
What do you see that is abnormal?
The heart
Shows early infiltrates (neutrophils) and congested blood vessels
This is from heart tissue also. What do we see here that should not be?
Later cellular infiltrates - mononuclear
On your pathology rotation you are assisting in an autopsy - the pathologist shows you this sample from the cadaver and asks you what the time frame from the onset of the MI was.
You answer?
6-8 hours, due to the presence of neutrophils and absence of macrophages.
What are two cytokines that increase the expression of selectins and integrin ligands on endothelium?
TNF and IL-1
What type of cell is this?
Is it active or dormant?
How do you know these things?
Neutrophil - multilobed nucleus
Has recently been activated - we see toxic granulation here.
What type of cell is this?
Is it active?
What are the signs we see in this cell specific for?
Still a neutrophil
Active - the clear spaces we see are toxic vacuoles. The presence of these is highly specific for sepsis.
What does the arrow indicate on this neutrophil?
The arrow points to an inclusion - called a Dohle body, which is precipitated RNA. This indicates the cell is constructing proteins.
What are the steps of phagocytosis?
- Recognition and attachment of the particle to be ingested by the leukocyte
- Engulfment, with subsequent formation of a phagocytic vacuole
- Killing or degradation of the ingested material.
How is the intracellular destruction of microbes and debris typically accomplished?
ROS - reactive oxygen species (or intermediates) and reactive nitrogen species - primarily nitric oxide (NO).
AND, lysosomal enzymes.
What are we looking at here?
NETs - neutrophil extracellular traps.
Extracellular fibrillar networks that provide a high concentration of antimicrobial substances at sites of infection and prevent the spread of the microbes by trapping them in the fibrils.
NETs are essentially just fancy…?
Biofilms
What are three examples of leukocyte mediated injury
- Collateral damage - as part of a normal reaction against microbes. In cases where a pathogen is difficult to eradicate, the host response can contribute more to the disease pathology than the microbe itself.
- Autoimmune disease - When the inflammatory response is inappropriately directed against host tissues.
- Excessive reaction to usually harmless environmental substances as in allergies and asthma.
The termination of the acute inflammatory response occurs because of what three things?
- Mediators of inflammation are produced in rapid bursts only as long as the stimulus persists.
- Have short half lives
- are degraded after their release
What are the most important mediators of acute inflammation?
- Vasoactive amines and lipid products
- Prostaglandins
- leukotrienes
- Cytokines and chemokines
- Products of complement activation
How are cell derived mediators of inflammation stored normally?
Sequestered in intracellular granules. OR synthesized de novo in response to a stimulus