Pain PDF - Pathophysiology of Pain

Week 10 Acute and Chronic Pain Pathophysiology of Pain Clinical setting addressing pain ○ Elevated BP ○ Elevated HR Four stages of pain ○ Transduction occurs when a stimulus such as pressure or chemical irritation is converted into a nerve...

Week 10 Acute and Chronic Pain Pathophysiology of Pain Clinical setting addressing pain ○ Elevated BP ○ Elevated HR Four stages of pain ○ Transduction occurs when a stimulus such as pressure or chemical irritation is converted into a nerve signal an action potential at the sensory level occurs at the ends of the sensory nerve cells whose terminal’s are sensitive to this type of stimulus these cells are known as nociceptors ○ distributed throughout the body ○ specialized receptors that send pain signals to the brain and the spinal cord ○ after they send signal second stage of pain occurs tissue damaging stimuli activate nerve endings tissue injury Inflammatory process chemical mediators substance that is being produced ○ serotonin ○ prostaglandin ○ bradykinins ○ all of these will release when there is an inflammatory response  These chemicals will alter the membrane potential of the pain receptor if depolarization is sufficient action potentials are generated ○ process that occurs in the neurons nerve cells other excitable cells ex: muscle cells ○ when the cell membrane voltage becomes less negative ○ moving closer or beyond zero ○ ions such as sodium and potassium that are crossing the cell membrane to generate impulses ○ when these impulses are conducted centrally the second phase will start whenever there is a tissue injury in the cell membrane prostaglandins are being formed then a ○ enzyme phospholipase A breaks down phospholipids in the cell membrane and converts them to arachidonic acid ○ arachidonic acid goes through a further breakdown by an enzyme known as Cyclooxygenase plays a role in forming prostaglandins Motrin prevents the formation of cyclooxygenase it’s able to decrease the production of prostaglandins  prostaglandins lowers the threshold of the nerve endings and this causes them to be sensitive to bradykinins bradykinins will then cause the pain protective lining of the stomach platelet aggregation: helps platelets join together to stop bleeding ○ blood flow: helps facilitate blood flow in the kidneys pain, fever, and inflammation: NSAIDs inhibit COX to reduce inflammation Celebrex/celecoxib is a cox-2 ○ Transmission the process of transferring that pain information from peripheral to central nervous system the message is carried from the injury site to the brain Peripheral nervous system is all of nerves outside of central nervous system (brain and spinal cord) these signals are transmitted along the nerve fibers nerve fibers comprise of two main types unmyelinated ○ C fibers dull throbbing pain ○ conduct impulses slowly Myelinated ○ A delta fibers cause sharp prickly pain ○ carry impulses faster rate  ○ myelin sheath is made of protein and fatty substances Able to allow impulses to be conducted faster along nerve cells ○ Perception subjective awareness of pain, which involves integrating sensory messages into a coherent whole Individual will experience an uncomfortable awareness associated with a specific area of the body depends on transmission of pain signals through the thalamus to the cortex and the limbic system thalamus is responsible for relaying information from our receptors to the various parts of our body to the cerebral cortex cerebral cortex interprets this information as touch pain temperature pain threshold the level of pain stimulation required to be perceived different from one person to the next ○ never judge a person/patient’s threshold pain tolerance degree of pain an individual is willing to bear before seeking relief pain expression the way in which the pain experience is communicated to others  ○ Modulation adjusting or regulating the perception of pain takes place in the central nervous system amplify or dampen the pain signals that have been transmitted process that reduces activity in the transmission system occurs in the spinal cord especially dorsal horn dorsal horn acts like a computer ○ collects and analyzes what is occurring during pain Definitions of Pain unpleasant sensory and emotional experience associated with actual or potential tissue damage pain is whatever the experiencing person says it is and exists whenever he/she says it does ○ our responsibility is to relieve pain ○ methadone is given to a person with opioid use disorder Types of Pain Acute ○ short lived ○ warning to the body that damage is occurring at the tissue level ○ fracture, sudden traumatic accident ○ sudden burn ○ accidentally lacerating a certain area ○ surgical procedure ○ ischemic pain ○ post-operative pain we need to advocate for these patients  elevation BP elevation HR elevation RR moaning and groaning, crying Chronic ○ pain that last 6 months or longer ○ lack of sleep ○ fatigue ○ irritability ○ pain severe ○ narcotics are not the recommended drugs dependency can occur due to taking these medications ○ examples happens when lifting always lift when bed is raised lift with another person assisting the lift using good body mechanics ○ depression occurs ○ A whole team is needed for specific patients to help them relieve chronic pain Somatic pain ○ well localized Know exactly where it hurts point to the specific sight where it hurts ○ Sharp ○ stabbing pain ○ aching ○ throbbing pain ○ examples  incision laceration visceral pain ○ diffuse deep cramping ○ sharp and stabbing pain ○ example insertion of a chest tube To re expand the lung Pushed into the lung need to have medication ready to administer to patient Neuropathic pain ○ shock like ○ nerve pain ○ phantom pain what amputees experience never tell a patient that pain can not occur, you need to be sensitive during this time this pain will resolve with time three locations of pain ○ localized confined to one specific area or area of body ○ radiating If pain is moving more intense pain if it is radiating ○ referred pain that is often felt in places remote from the location of the affected organ example  In myocardial ischemia ○ you can have left arm pain ○ Experience left hand or jaw brain freeze Kidney pain ○ lower back pain ○ urinalysis is done hematuria needs to be seen ○ kidney stones are not smooth when moving through the renal system they rip tissue and this causes pain ○ morphine is given for pain ○ best way to prevent kidney stones water ○ kidney stones are made of calcium oxalate decrease foods high in oxalate almonds cashews bran cereals bagels Oxalate binds to calcium as it leaves the body ○