Presentation on theme: "Inflammation The local response of the body to an irritant Purpose"— Presentation transcript:
1 Chapter 4. Tissue Response to Injury: Inflammation, Swelling, and Edema
2 Inflammation The local response of the body to an irritant Purpose Defend the body against alien substancesDispose of dead and dying tissue so repair can take place
3 Cardinal Signs of Inflammation Rubor: rednessCalor: heatEdema: swellingDolor: painFunca laesa: functional lossEach of these signs will occur to some degree when tissue is injured and the body responds with the inflammatory process.
4 Common Misconceptions of Inflammation Do you need to limit or eliminate inflammation?No. Inflammation is necessary.Repair will not occur without inflammation.You cannot eliminate inflammation.You can only minimize the signs of inflammation.
5 Common Misconceptions of Inflammation (cont.) Swelling, edema, and inflammation are synonymousSwelling and edema occur during inflammation.Edema and swelling are not the same.All edema causes swelling, but not all swelling is caused by edema.
6 Phases of Inflammation Inflammation consists of sequential and overlapping events.Primary injuryUltrastructural changesChemical mediationHemodynamic changesMetabolic changesPermeability changesLeukocyte migrationPhagocytosis
7 Primary InjuryAny occurrence that impairs tissue structure or functionMost sports injuries are caused byMacrotrauma (impact or contact)Microtrauma (overuse, cyclic loading, or friction)There are many other types of injury, each of which results in the same basic inflammatory reaction.Other examples?
8 Primary Injury (cont.) Other causes of injury include Physical agents (trauma, burns, radiation)Metabolic processes (hypoxia)Biological agents (bacteria, viral, parasitic, infection)Chemical agents (acids, gasses, organic solvents, endogenous chemicals)Endogenous chemicalsNormal secretionsIn abnormal locations (gout)In increased quantity in a normal location (stomach ulcers)The magnitude after each phase varies according to the causative agent
9 Ultrastructural Changes Cellular membrane is disrupted and eventually breaks down.Contents spill out into the extracellular spaces, thereby killing the damaged cell.Two causesDirectTrauma (primary injury)IndirectHypoxia (oxygen deficiency)Enzymes (chemicals)In cells adjacent to the primary injury
10 Ultrastructural Changes (cont.) Occur as a direct result of trauma (primary injury) and indirectly as a result of hypoxia (secondary injury)We will discuss this in more detail later in this chapter (see “Orthopedic Injury Model”).
11 Ultrastructural Changes (cont.) LysosomeSupplies chemicals that digest foreign material within the cell and gets rid of it.If the membrane of the lysosome ruptures, its contents will attack and digest other material.
12 Chemical Mediation Histamine, bradykinin, and other chemicals Modify and regulate the rest of the inflammatory response to:Neutralize the cause of the injuryRemove cellular debris so repair can take place
13 Hemodynamic ChangesArteries dilate, increasing blood flow to the injured area.However, blood vessels that were previously inactive open, so blood flow through individual vessels decreases.Slowing of blood flow is necessary, so WBCs can move to the margins.
14 Hemodynamic Changes (cont.) LeukocytesMarginateTumble along the vessel wallAdhere to the vessel wall near an opening
15 Hemodynamic Changes (cont). Leukocytes begin passing though the vessel wall.
16 Metabolic Changes ↓ Energy ↓ Oxygen, causes cell to switch to anaerobic metabolismMembrane functions slow down.Sodium pump maintains the concentration of intracellular sodium at a very low level.
17 Metabolic Changes (cont.) ↑ Sodium concentration in cell and organelles↑ Water in cellCells swell and burst↑ Intracellular acidosis (lactic acid)Membrane attackedLysosome digests cell.
18 Permeability ChangesHistamine and bradykinin increase the permeability of small blood vessels.The endothelial cells contract, pulling away from each other.Gaps are left, through which the WBCs can move out of the vessel and to the injury site.
19 Leukocyte MigrationWBCs adhere to the endothelium (vessel wall) and/or to other white blood cells.(Reprinted with permission from McLeod I. Inflammation. Kalamazoo, MI: Upjohn, 1973.)
20 Leukocyte Migration (cont.) WBCs move out of the vessel by squeezing through the endothelial gaps.Neutrophils first, then larger macrophages(Reprinted with permission from McLeod I. Inflammation. Kalamazoo, MI: Upjohn, 1973.)
22 Leukocyte Migration (cont.) NeutrophilsTravel fast and arrive at the injury site firstProvide the first line of defenseWhen they die, they release chemical mediators that attract macrophages.Death of neutrophils results in a large concentration of chemical mediators released by the cells.
23 Leukocyte Migration (cont.) MacrophagesLive for monthsLong-lasting second line of defenseRelease potent enzymes that may destroy connective tissue, thus adding to the injuryRelease chemical mediators that may prolong inflammationRelease factors that aid in healingSecrete proteins that are important in defense mechanisms
24 PhagocytosisDigestion of cellular debris and other foreign material into pieces small enough to be removed from the injury site
25 Chronic InflammationResults from microtrauma but does not necessarily involve an inflammatory reactionExample: clinically diagnosed Achilles tendinitis and patellar tendinitis in which there is no evidence of an inflammatory reactionStructural disruption and microvascular damage may occur (causing pain and other symptoms) before the classic inflammatory process is set into action.
26 Orthopedic Injury Model What happens when a muscle is pulled or an ankle is sprained?Just put an ice bag on it, right?WRONG.This is overly simplistic.Techniques must be based on sound theory if they are to be developed and improved.It is essential to understand the body’s response to injury.
27 Orthopedic Injury Model (cont.) Example: typical tissue undergoing a typical muscular injuryUsed to illustrate inflammation in relation to orthopedic injuries
28 Orthopedic Injury Model (cont.) Normal tissueCellsTwo blood vessels (A, B)Two nerves (1, 2)
29 Orthopedic Injury Model (cont.) Contusion with injury to:Three cellsNerve 1Blood vessel B
30 Orthopedic Injury Model (cont.) Immediate ultrastructural changeLocal nerves and blood vessels may be disrupted or broken.This damage is called primary traumatic damage.
31 Orthopedic Injury Model (cont.) HemorrhageFew minutes only (usually)Clot forms, stopping hemorrhage.Pain, from damaged nerveHematoma forms.
32 Orthopedic Injury Model (cont.) Pain, from damaged nerveMuscle spasm and more painInhibition of muscular strength, range of motion, etc.Body attempts to protect itself by splinting the area, thus preventing aggravation of injury.
33 Orthopedic Injury Model (cont.) The damaged cells release chemical mediators as a signal to the body that an injury has taken place.Extravascular hemorrhage occurs from broken blood vessels.Swelling occurs.Injury site
34 Orthopedic Injury Model (cont.) Fibrin forms into strands, creating a network somewhat like a fishnet.This net captures circulating platelets.A plug forms to seal the damaged vessel.
35 Orthopedic Injury Model (cont.) Chemical mediators released from dying cells causeHemodynamic changesPermeability changesLeukocyte (white cell) migration
36 Orthopedic Injury Model (cont.) Secondary enzymatic injury begins.
44 Orthopedic Injury Model (cont.) The inflammatory response is not all positive.ExampleSlowed blood flow in the vessels on the periphery of an injury and decreased blood flow from the damaged vasculature result in less oxygen to the cells.If prolonged, secondary hypoxic injury occurs.The total amount of damaged tissue is increased, and more debris is added to the hematoma.
45 Secondary Injury Model Body’s response to tissue damaged by trauma (primary injury) leads to further tissue damage, known as secondary injury.Two separate mechanisms result in secondary injury:EnzymaticHypoxia
46 Decreased Metabolism Theory In normal tissueO2neededO2available
47 Decreased Metabolism Theory (cont.) After injuryO2neededavailable
52 What Is Edema? Accumulation of fluid in the tissue What causes it? Must first understand normal fluid dynamics
53 Fluid Filtration in Normal Tissue Fluid outFluid in
54 Fluid Filtration in Normal Tissue (cont.) All fluid leaving the capillary is returnedTwo-thirds via capillaryOne-third via lymphatic system
55 Fluid Filtration in Normal Tissue (cont.) Occurs constantly between capillary and tissueSum of multiple forcesIn capillary and tissueOncotic (osmotic) pullsHydrostatic pushesOH
56 Hydrostatic Pressure Pressure exerted by a column of water The higher the column of water, the greater the pressure.Example: swimmingThe deeper you go, the higher the column of water above you and the greater the pressure.The depth of the water, not the amount of water, is important.Hydrostatic pressure is exerted by the water portion of the blood.
57 Hydrostatic Pressure (cont.) Hydrostatic pressure pushes water.Capillary hydrostatic pressure pushes fluid out of the capillary.Tissue hydrostatic pressure pushes fluid into the capillary.capillaryCHPtissueTHP
58 Oncotic Pressure capillary tissue COP TOP Also called colloid osmotic pressureResults from the attraction of fluid by free proteinTissue oncotic pressure pulls fluid out of the capillary.Capillary oncotic fluid pulls fluid into the capillary.tissuecapillaryCOPTOP
59 Fluid Filtration in Normal Tissues, Revisited Sum of all forces
63 What Causes Edema?Imbalance of fluid filtration caused by an injury
64 Capillary Filtration Pressure Changes after Injury Hematoma (tissue debris and hemorrhage) dumps large amounts of free protein into tissue spaces.Increased tissue oncotic pressure
65 Fluid Filtration in Injured Tissue Injury results in a great increase in the tissue oncotic pressure.TOP
66 Fluid Filtration in Injured Tissue (cont.) Fluid outFluid in>
67 Fluid Filtration in Injured Tissue (cont.) Fluid accumulates in tissue.
68 Fluid Filtration in Injured Tissue (cont.) More fluid accumulates in tissue.
69 Fluid Filtration in Injured Tissue (cont.) Even more fluid accumulates in tissue.
70 What Is Swelling? Hemorrhaging and edema Can do nothing about hemorrhagingCan minimize edema
71 What Causes Swelling?CapillaryTissue spacesLymphatic
72 How Do You Prevent Swelling? CapillaryTissue spacesLymphatic
73 How Do You Prevent Swelling? (cont.) CapillaryTissue spacesLymphatic
74 How Do You Prevent Swelling? (cont.) CapillaryTissue spacesLymphatic
75 How Does Cold Decrease Swelling? As cold decreases secondary hypoxic injury, the amount of free protein in tissues decreases.This causes less tissue oncotic pressure (the major factor for edema).Cold can prevent edema from occurring only if applied soon after injury.Once edema develops, cold application cannot decrease that edema.
76 Decreased Metabolism Theory, Revisited Secondary hypoxic injuryNormal tissueInjured tissueInjuredand with cryotherapyO2 neededO2 available
77 Time Course of Swelling Swelling immediately after injury is the result of direct hemorrhaging.Edema begins minutes to hours after injury and continues to develop over many hours.Accounts for the delayed nature of most swelling.
78 Secondary Injury and Edema Secondary injury results in increased edema, and increased edema can contribute to increased secondary injury.Two mechanismsAs edema develops, the distance between blood vessel and tissue cells increases.More difficult for oxygen and other substances to diffuse from the circulatory system to the tissueEdema can compress the blood vessel, thus decreasing circulation to the area.
79 Capillary Filtration Pressure Changes after Injury, Revisited If swelling is the result of edema, why does the area turn black and blue?Isn't this caused by oxidized blood?Some is, but most discoloration in the muscle is caused by oxidized myoglobin from the damaged musculature.
80 Common Misconceptions Concerning Ice and Inflammation Many think the purpose of ice is to decrease inflammation.However, inflammation is necessary to prepare for healing.Healing cannot take place until much of the cellular debris is removed from the area.So decreasing inflammation is not helpful.
81 Common Misconceptions Concerning Ice and Inflammation (cont.) Misconception results from confusing inflammation with swelling.The more the swelling is contained, the quicker the injury can heal.
82 Common Misconceptions Concerning Ice and Inflammation (cont.) Another misconception concerning ice is that it should be used until the swelling is gone.Ice is effective for preventing swelling but not for removing swelling.Swelling reduction occurs as free protein is removed from the area.
83 Summary Inflammation is the body’s response to any injury. Protects the body against invasion by foreign bodies and prepares the injured tissue for repair.After understanding inflammation, hemorrhaging, and edema, you will be qualified to educate your athletes and coaching staff, who commonly apply ice to decrease inflammation after an injury.You can explain that swelling is one of the signs of inflammation but is not the process itself; they are separate but related processes.