Week 2 Ch 7 Pain PDF

ANTI- INFLAMMATO RY MEDICATION Chapter 7 S AND PAIN RELIEF INFLAMM ATION The normal response when an injury or infection occurs in any area of the body Cardinal signs are pain, heat, redness, and swelling The body responds with a series of actions called the inf...

ANTI- INFLAMMATO RY MEDICATION Chapter 7 S AND PAIN RELIEF INFLAMM ATION The normal response when an injury or infection occurs in any area of the body Cardinal signs are pain, heat, redness, and swelling The body responds with a series of actions called the inflammatory pathway Damaged cells send out chemical signals that initiate the inflammatory cascade, increasing blood flow to the damaged area INFLAMMATORY CASCADE When the inflammatory cascade is initiated as the result of injury, phospholipids in the cell membrane are broken down by phospholipase Causes the formation of arachidonic acid, and enzyme released by the body during tissue damage PAIN RESPONSES Change in personality Changes in posture or stance Decreased activity and reluctance to move Decreased self-grooming Diminished desire or reluctance to eat Increased or abnormal respiration Self-mutilation or painful area or site: Licking, biting, or scratching; guarding a painful area Whining, crying, growling, whimpering Weight loss and dehydration PAIN ASSESSMENT SCALE FOR FELINES Courtesy of Colorado State University Veterinary Medical Center  Visceral  Internal organ or viscera lining the organs are disrupted or injured; thorax, pelvic region, pleura, and abdomen THE 3 Somatic TYPES  Dull or aching pain initiated in the musculoskeletal tissues on the surface of the body; generally alleviated by rest and OF PAIN aggravated by activity Neuropathic  Injury to the spinal cord and/or peripheral nerves; tends to occur at the site of injury or below it CYCLOOXY GENASE Pain from inflammation results from the enzyme cyclooxygenase (COX) COX-1 is continuously produced in the body and ensure that prostaglandins are kept at constant levels COX-2 is only formed when an inflammatory response to tissue injury occurs Both COX-1 and COX-2 convert arachidonic acid to prostaglandins resulting in pain and inflammation Only inhibition of COX-2 is thought to be therapeutic ANTI-INFLAMMATORY MEDICATIONS Corticosteroids are hormones produced by the adrenal cortex; corticosteroid drugs are synthetic replications of these hormones. Corticosteroids belong to one of two groups – mineralocorticoids or glucocorticoids. Mineralocorticoids  Occur naturally in the body in the form of the hormone aldosterone;  Synthetic forms are not commonly used in veterinary medicine but help the body retain water and sodium which has an effect on tissue healing Glucocorticoids  Occur naturally in the body mostly in the form of cortisol, a hormone released in response to low blood glucose levels and stress  Responsible for anti-inflammatory and immunosuppressive reactions; most steroids used in veterinary medicine are classified as glucocorticoids  CORTICOSTER OID PRODUCTION AND RELEASE Production and release is controlled by two different mechanisms:  Feedback mechanism utilized by the hypothalamus, anterior pituitary, and the adrenal cortex  Stress (internal and external stressors)  Inhibition of cortisol is controlled by a negative feedback loop, a process in which the response reduces or slows down the stimulus  When concentrations of cortisol in the blood reach a certain level, corticotropin- releasing hormone (CRH) is inhibited, thereby stopping adrenocorticotropic hormone (ACTH) secretion and inhibiting further production of cortisol COMMON USES AND BENEFITS OF CORTICOSTEROIDS Reduction of Treatment of Addison’s musculoskeletal disease inflammation Treatment of certain Relief of allergic neoplasms and cancers responses Relief of pruritus and Termination of late stage other dermatologic pregnancy conditions Reduction of tissue Reduction of scarring by damage delaying wound healing See Table 7.1 for Treatment of autoimmune commonly used or immune-mediated corticosteroids disorders ADVERSE EFFECTS OF CORTICOSTEROIDS Delayed wound healing Polyuria and polydipsia Decreased immune Thinning of skin and response muscle atrophy GI ulcers and bleeding Hyperadrenocorticism (Cushing’s Disease) Corneal ulceration (if present when administered topically to the eye Abortion HISTAMINES AND ANTIHISTAMINES IN THE INFLAMMATORY PROCESS Histamines are chemicals Antihistamines block the released to assist the immune biding of histamines to H1 system in battling allergens or H2 receptors Two receptor types: H1 receptors result in an allergic Used to inhibit the reaction; H2 receptors turn the inflammatory process allergic reaction off (negative when histamines are feedback) and increase released during and stomach acid allergic reaction Stored in the body’s mast cells and basophils H1 blockers are used to treat allergic reactions Histamines are released into and anaphylactic shock nearby cells when the immune system perceives a threat, H2 blockers will suppress causing vasodilation and gastric secretions and edema help with GI function HOW ANTIHISTAMINES WORK PAIN MANAGEMENT: OPIOIDS Can be used as both anesthetics and analgesics All opioids are controlled substances Extremely effective at controlling moderate to severe pain Binds with specific receptors in the CNS, preventing the perception of pain Inhibit ascending pathways of pain perception and activate descending pathways Four opioid receptors: Mu, kappa, delta, and opioid receptor like-1 (ORL-1)  Opioids are classified into categories depending on their effect Agonists bind closely to the OPIOID receptors and produce a desired response AGONIS Partial agonists behave the same way, but to a lessor extent TS Antagonists prevent a biological response from occurring and cause no opioid effect Mixed agonists/antagonists will have varying effects LOCAL AND TOPICAL ANESTHETICS Commonly used to relieve pain as well as prevent it Can be used in the administration of nerve blocks Work well to numb the eyes, ears, and larynx Local anesthetics work directly on the intended site -Caines  Help alleviate pain and inflammation by interfering with some aspect of the inflammatory cascade NONSTE Decrease inflammation after ROIDAL surgery or trauma and can greatly ANTI- enhance analgesia INFLAMM Inhibit COX enzymes so that fewer prostaglandins are produced ATORY Inhibition of COX-2 promotes the DRUGS effectiveness of the drug NSAIDS Inhibition of COX-1 produces unwanted side effects such as GI upset HOW NSAIDs WORK NSAIDs Advantages Adverse Effects Availability Vomiting Long duration of action GI ulceration and bleeding Low cost Hepatotoxicity Ease of administration Nephrotoxicity Bone marrow suppression Reduction of platelet aggregation Inhibition of cartilage metabolism  Can be used to treat inflammatory reactions in muscle tissue and to MUSCL decrease the severity of muscle spasms E Spasmolytics or RELAXA antispasmodics inhibit nerve impulses or reduce excitability of NTS motor neurons, allowing the muscle to relax Neuromuscular blockers inhibit transmission of a neurotransmitter at the end of a neuromuscular junction Also used as part of a preanesthetic protocol