Acute and Chronic Inflammation

Question 1

Discuss the 5 cardinal signs of injury

Answer 1

• Redness
• Warmth
• Swelling
• Pain
• Loss of Function
• Latin, respectively: rubor, calor, tumor, dolor, functio laesa (rhymes pretty good til the end there– even first century Roman med students needed their mnemonics. Trust a 19th-century German to mess it up.).

Question 2

Describe how redness, swelling and warmth can be explained physiologically

Answer 2

• Redness and warmth are due to increased blood flow secondary to vasodilation of capillaries and arterioles. Note brief initial pallor.
• Swelling, pain, and loss of function are due to increased vascular permeability, secondary to endothelial alteration to allow exudation of plasma fluid into the extracellular space (pain due to irritation of nerves by exudate) and possibly extravasation of leukocytes. Note that leukocytes can cause additional tissue damage, which can in turn can trigger more inflammation.

Question 3

Transudate

Answer 3

fluid leaking from capillaries not due to inflammatory processes.
o Ie: ascites in peritoneum due to increased hydrostatic pressure in capillaries

Question 4

Exudate

Answer 4

fluid leaking from capillaries due to inflammatory processes.
o Ie: well, just that. As we’ve been saying, can be caused by inflammation.

Question 5

Name organs directly exposed to the outside environment and examples of how they maintain barriers

Answer 5

To “Outside”: Skin / Respiratory System / Gut

a. Epithelial cells: Ability to Regenerate
- Ectodermal Derived: Skin
- Endoderm-Derived: Gut, Respiratory, Urinary
b. Epithelial defense mechanism
(1) Squamous Epithelium: Skin and Esophagus
- Surface cells slough with passage of foreign objects (e.g. in esophagus: food)
- Epithelial cells turn over
- Mucus / Sebaceous / sweat lubricant secretion by specialized glands
(2) Columnar Epithelium:
- Mucus secretion by epithelium
- Epithelial cells turn over

Question 6

Identify the possible outcomes of acute inflammation

Answer 6

Complete resolution
o	Macrophage clean up of necrotic debris
o	Tissue regeneration
o	Lymphatic drainage decreases edema
o	Scarring
•	Abscess formation
•	Progression to chronic inflammation

Question 7

Describe the process of and give clinical examples of collateral tissue damage associated with inflammation

Answer 7

Damage to normal tissue is a common outcome in the setting of an inflammatory process
1. Cells Responsible for Damage
a. Neutrophils: die within 1-2 days after migration –> cellular contents released
b. Macrophages
2. Substances Responsible for Damage
a. Inflammatory Mediators
- Reactive O2 Species
- Nitric oxide
b. Content from neutrophils, macrophages,
and other cells
- Enzymes:
- Proteases
- Acid hydrolases
After neutrophils degranulate –> die
Macrophages eventually die off, or wander into the lymphatics
Macrophages are very powerful—but the same weaponry can cause considerable tissue destruction.
Tissue destruction is one of the hallmarks of chronic inflammation

Question 8

10. Recognize the role of lymphatics and the potential outcomes if the lymphatic system cannot contain the infection

Answer 8

• Lymphatics drain fluid accumulated in tissue
o Lymphatics are almost as abundant as capillaries
o Lymph nodes contain lymphocytes (T and B cells) where antigen presentation occurs
o Unfortunately, lymphatics are also a channel for dissemination of injurious agent
- Ex. Infection of hand with red streaking up arm
• Lymphangitis
• Lymphadenitis (inflammation of lymph node)
o If lymphatic system cannot contain infection, microorganisms gain access to blood –> bacteremia, fungemia, viremia

Question 9

List clinical examination findings associated with an inflammatory process: local

Answer 9

• redness = vasodilation 0
• heat = vasodilation
• swelling = vascular perm.
• pain = mediators/local pressure no nerves
• loss of function = swelling

Question 10

List clinical examination findings associated with an inflammatory process: systemic

Answer 10

• Sleepiness / Grogginess
• Anorexia
• Fever
• Elevated white blood cell count (WBC)
• Blood pressure alterations
  
  • e.g. evaluate for hypotension / “shock”

Question 11

List useful laboratory tests supporting an inflammatory process

Answer 11

• Hematologic profile
• acute phase reactacnts
• DIC-related Markers (disseminated intravascular coagulation)
• Microbiology and Immunology Laboratory Studies
• Immunoglobin quantitation (e.g. if immunodeficiency suspected)
• not typically evaluated

Question 12

List useful laboratory tests supporting an inflammatory process: Hematologic profile

Answer 12

• White blood cell count
- Automated
- Manual (looking for atypia)
• Differential including platelet count

Question 13

List useful laboratory tests supporting an inflammatory process: Acute Phase Reactants

Answer 13

• Erythrocyte sedimentation rate (ESR)

* C-Reactive protein

Question 14

List useful laboratory tests supporting an inflammatory process: DIC-Related Markers (disseminated intravascular coagulation)

Answer 14

• Fibrin split / degradation products
o D-Dimer
• Platelet count (“consumption”)

Question 15

List useful laboratory tests supporting an inflammatory process: Microbiology and Immunology Laboratory Studies

Answer 15

•	Rapid identification testing
o	Cryptococcus, some viruses
•	Culture
o	With bacterial / fungal sensitivities
•	Serology (IgM vs. IgG antibodies)
o	Viral and fungal

Question 16

List useful laboratory tests supporting an inflammatory process: not typically evaluated

Answer 16

•	Chemical mediators – mostly short / local acting; lack specificity (e.g. elevated in infectious and autoimmune processes)
o	Prostaglandins
o	Leukotrienes
o	Thromboxanes
o	Interleukins
o	etc.