Pain Management Flashcards
What is pain?
An unpleasant sensory and emotional experience associated with actual or potential tissue damage.
What are three pain assessments?
Physical, Functional & Psychosocial
What are the three types of neuron?
1st - sensation of pain
2nd - modulation & propagation of pain
3rd - translation and perception of pain
What are the three types of neuron fibres? What do they do?
A- delta = acute pain - middle
A- Beta = sensation/ other types of stimulation - fastest
C fibre = Chronic pain - Slowest
How is pain perceived by the body?
Activation of nociceptors, found at the nerve terminals of 1st order neurons, these are pain mediator receptors. These are stimulated by prostaglandins, substance p & nociceptins. This propagates the impulse in the first-order neuron, to the second-order and finally to third-order neurons.
What is the most common pain associated with acute pain?
Anxiety
What is the most common pain associated with chronic pain?
Depression
What are 3 characteristics of acute pain?
Myelinated - faster conduction as can jump between nodes of Ranvier
Large Diameter
Fast conduction - A-Delta
What are 3 characteristics of chronic pain?
Unmyelinated
Slower conduction - C fiber
Small diameter
What can acute and chronic pain each be accompanied with?
Acute - Stress & Anxiety
Chronic - Depression
What is adjuvant medication?
Not true analgesics
Pt with chronic or acute pain - on analgesics - but will be experiencing other pain like stress/ anxiety/ depression so added therapies are required additionally. These for example could be anti-depressants.
What is neuropathic pain associated with?
Diabetic pain. This is where nerve terminals are irritated.
What is gabapentin and pregabalin used for?
Neuropathic pain - help in reducing sensitivity of nerve terminals
What is the stepwise approach to starting opioid medication?
Step 1 - NSAIDs/ Non opioid for mild pain= +/- Adjuvant
Step 2 - Opioid, MILD TO MODERATE + NSAIDs +/- Adjuvant
Step 3 - Opioid + NSAIDS, MODERATE TO SEVERE
Can you add weak opioids alongside strong opioids?
No, both types of opioids activate the same receptor (nociceptor). The addition of weak opioids causes competition for the receptors and causes a reduction in potency, when just giving a strong opioid
Can opioids be given alongside NSAIDs?
Yes, opioids act on nociceptors whereas NSAIDs act on COX1 & COX2 inhibiting prostaglandin production
Give an example of a strong opioid
Morphine
Give an example of a weak opioid
Codeine
What is the preferred analgesic?
Paracetamol
Why can’t you just start with a strong opioid?
Strong side effects therefore need to work way up. Many fatal side effects ie resp depression
What is PCA?
Patient controlled analgesia
Patient is set up with a machine that allows them to administer their own analgesic whenever they experience pain by pressing a button.
The software used only allows one dose to be administered as it locks until another dose can be taken. For example if a drug is allowed tds but pt wants two doses within one hr - can’t happen
Why is PCA good?
Pt uses less doses - therefore less medicine is wasted.
What is a risk of PCA?
Infection
What are benefits of epidural?
Require less dose as drug is being delivered to the direct site of action (dorsal horn)
Reduces side effects
What is TENs machine used for? How does it work?
Pain Management used in hospitals. Used for 10-15 mins and provides 8 hrs of analgesics
If pt has both chronic and acute pain which does he feel?
Pt is being stimulated by two types of pain acute and chronic; patient will only feel one type of pain- acute. This is due to its conduction speed being greater in the A-delta fiber than the C fiber. Only one fiber can be stimulated at once. Once the impulse reaches the second order neuron it goes into absolute refractory period where it can’t receive or transmit any other impulse. Until the current impulse disappears
What is the MOA of a TENS machine?
A-beta is stimulated by the transcutaneous electrical nerve stimulator machine. This causes tingling and high mechanical stimulation. A-beta is the fastest first order neuron and therefore travels and reaches the second order neuron causing absolute refractory period meaning no other pain ie chronic or acute can be felt until the impulse is removed.
Benefits of the TENS machine
Provides 8 hr analgesic
Activates endogenous system - endorphins = even more analgesia
What is neuropathic pain? What vitamin complex is used as a prophylactic?
Irritation of the nerve terminal. Common in diabetic pt. Vitamin B complex
If neuropathic pain occurs what is treatment?
Gabapentin and Pregabalin - Adjuvant Treatment
Duloxetine
Tramadol
How does neuropathic pain form?
As a result of damage to the system that normally signals pain. May arise from a heterogeneous group of disorders that affect the peripheral and central nervous systems
What are three characteristics of neuropathic pain?
Glove and stocking distribution
Burning or shooting pain
Allodynia - severe pain that isn’t normally there
What is used to treat trigeminal neuralgia?
Normally requires surgery but Carbamazepine
If mild trigeminal neuralgia
Carbamazepine and injection of glycine
What is RA?
Where immune cells attack tissues of the body causing inflammation. This affects the synovial joints. It is long life.
Hurts bone, lungs, joints
What is treatment for RA?
Methotrexate
Sulphsalazine
What are other treatments alongside M&S
DMARDS
Oral NSAIDS
Low dose aspirin must be taken before substituting or adding other analgesics
What is osteoarthritis?
Joint pain associated with loss of function and reduced quality of life
Affects joints in hand, knees and hips.
Associated with remodelling of adjacent bone, loss of cartilage and inflammation.
Pain is so bad it reduces pt ability to do certain tasks
What is the main difference between osteoarthritis and RA?
Osteoarthritis doesn’t progress where as RA does.
What is treatment of Osteoarthritis?
Paracetamol & NSAIDS
Insufficient? - Add opioid
Topical Capsaicin - Causes depletion of substance P resulting in decreased inflammation.
Should you prescribe glucosamine to osteoarthritic pt?
No, systemic and only successful in early stages (normally not diagnosed)
What is breakthrough pain? How is it treated?
An acute attack of chronic pain. This is controlled with Opioids
What are cluster and tension headaches treated with?
NSAID
