mellss yr 4 anesthesia pain management
TRANSCRIPT
Nur Amalina Aminuddin Baki
082012100067
Pain Management
Classification of pain
Acute
Chronic
Evaluation of pain
Selected pain syndromes
Perception
Pain perception depends on specialized neurons
that function as receptors, detecting the stimulus,
and then transducing and conducting it to the central
nervous system.
PROTOPATHIC (NOXIOUS) EPICRITIC (NONNOXIOUS).
• pain • light touch, pressure,
proprioception,
• and temperature discrimination
• high-threshold receptors • low-threshold receptors
• smaller, lightly myelinated (Aδ)
and unmyelinated (C) nerve
fibers
• large myelinated nerve fibers
Term Description
Allodynia Perception of an ordinarily nonnoxious stimulus as pain
Analgesia Absence of pain perception
Anesthesia Absence of all sensation
Anesthesia
dolorosa
Pain in an area that lacks sensation
Dysesthesia Unpleasant or abnormal sensation with or without a stimulus
Hypalgesia Diminished response to noxious stimulation (eg, pinprick)
Hyperalgesia Increased response to noxious stimulation
Hyperesthesi
a
Increased response to mild stimulation
Hyperpathia Presence of hyperesthesia, allodynia, and hyperalgesia usually
associated with overreaction, and persistence of the sensation
after the stimulus
Hypesthesia Reduced cutaneous sensation (eg, light ,touch, pressure, or
temperature)
Neuralgia Pain in the distribution of a nerve or a group of nerves
Paresthesia Abnormal sensation perceived without an apparent stimulus
Classification of pain
Acute and chronic pain.
Pathophysiology
nociceptive or neuropathic pain
Etiology
arthritis or cancer pain
Affected area
headache or low back pain
ACUTE PAIN
Caused by noxious
stimulation
Usually nociceptive.
Post-traumatic,
postoperative, obstetric
pain and pain associated
with acute medical
illnesses
Self-limited or resolve
with treatment in a few
days or weeks.
Types of acute pain
Somatic
Visceral
Somatic pain
Intensity and duration of the stimulus affect the
degree of localization.
Superficial Deep
skin, subcutaneous tissues,
and mucous membranes
muscles, tendons, joints, or
bones
well localized less well localized
sharp, pricking, throbbing,
or burning sensation.
dull, aching quality
Visceral pain
Due to a disease
process or abnormal
function involving an
internal organ or its
covering
Four subtypes are
described:
Localized visceral pain
Localized parietal pain
Referred visceral pain
Referred parietal pain
Referred pain are due to
:
Embryological
development and
migration of tissues
Convergence of visceral
and somatic afferent input
Visceral Parietal
dull, diffuse, and
usually midline.
sharp and
stabbing
sensation
localized or
referred
associated nausea,
vomiting, sweating,
and changes in
blood pressure and
heart rate.
CHRONIC PAIN
Pain that persists beyond the usual course of an acute
disease or after a reasonable time for healing to occur(1
to 6 months.)
May be
Nociceptive (musculoskeletal disorders)
Neuropathic (pain associated with peripheral or central neural
disorders)
Mixed (Cancer and chronic back pain)
Psychological and environmental factors play a major
role.
Attenuated or absent neuroendocrine stress responses
and have prominent sleep and mood disturbances.
Mechanism of chronic pain
Maybe caused by
combination of :
Peripheral
Spontaneous discharges;
Sensitization of receptors to
stimuli;
Up-regulation of adrenergic
receptors.
Central
Loss of segmental
inhibition,
Spontaneous discharges in
deafferentated neurons,
Reorganization of neural
connections.
Psychological
Psychophysiological
Learned or operant
behavior in which chronic
behavior patterns are
rewarded
Psychopathology
Pure psychogenic
mechanisms (somatoform
pain disorder)
Neuropathic Pain Mechanism
Involve peripheral-central and central neural mechanism.
Associated with lesion of peripheral nerves, dorsal root
ganglia, nerve root.
Mechanisms:
Spontaneous self sustaining neuronal activity in primary afferent
neuron.
Marked mechanosensivity
Short circuits between pain fiber and other type of fiber.
Functional reorganization of receptive filed in dorsal horn neurons.
Spontaneous electrical activity in dorsal horn cell or thalamic nuclei.
Release of segmental inhibition in spinal cord.
Lesion of the thalamus or other supraspinal structures
Systemic Responses To ACUTE
Pain
Cardiovascular (hypertension, tachycardia, enhanced myocardial irritability, and increased systemic vascularresistance.).
Respiratory (hypoxemia, hypoventilation, impair coughing and clearing of secretions.)
Gastrointestinal and Urinary (increases sphincter tone and decreases intestinal and urinary motility, stress ulceration and nausea, vomiting, and constipation)
Endocrine (negative nitrogen balance, carbohydrate intolerance, and increased lipolysis, sodium retention, water retention)
Hematological (Stress-mediated increases in
platelet adhesiveness, reduced fibrinolysis, and
hypercoagulability)
Immune (Stress-related immunodepression )
Psychological (anxiety and sleep disturbances )
Systemic Responses To Chronic
Pain
Observed only in patients with :
Severe recurring pain due to nociceptive mechanisms
Prominent central mechanisms (pain associated with
paraplegia0.
Absent in most patients with chronic pain.
Sleep ,depression, changes in appetite and stresses
on social relationships.
Evaluation of chronic pain
Pain measurement
Numerical rating scale,
Wong-Baker FACES rating scale,
Visual analog scale (VAS),
McGill Pain Questionnaire (MPQ)
Imaging studies
Pyschological
Minnesota Multiphasic Personality
Inventory (MMPI)
Beck Depression Inventory.
Electromyography and nerve
conduction studies
SELECTED PAIN
SYNDROMES
Entrapment syndrome
Neural compression
Narrow passage , genetic factors ,repetitive trauma
Diagnosis :
Electromyography and nerve conduction studies.
Neural blockade of the nerve with local anesthetic
Treatment :
Oral analgesics
Temporary immobilization
Surgical decompression.
Myofascial pain
Characterized by aching muscle pain, muscle
spasm, stiff ness, weakness, and autonomic
dysfunction.
Have trigger points in muscles or connective tissue
(levator scapulae, masseter, quadratus lumborum,
and gluteus medius muscles)
Palpation : tight,ropy bands over trigger points.
Pain radiates in a fixed pattern (not follow
dermatomes)
Gross trauma or repetitive microtrauma
Diagnosis: character of the pain and palpation of
discrete trigger
Treatment:
Spontaneously resolve
Local anesthetic (1–3 ml) trigger point injections.
Topical cooling with ethyl chloride / fluorocarbon spray can
also
Physical therapy
Fibromyalgia
Chronic widespread pain, fatigue, sleep disturbance, and heightened pain in response to tactile pressure
Diagnosis: 1. Widespread Pain Index (WPI) score of 7 or higher, and Symptom
Severity (SS) scale score of 5 or higher, or WPI of 3–6 and SS scale score of 9 or higher.
2. Symptoms present at a similar level for at least 3 months.
3. Absence of another disorder that would otherwise explain the pain.
Treatment: Cardiovascular conditioning, strength training, improving sleep
hygiene, cognitive behavioral therapy, patient education
pregabalin ,duloxetine ,and milnacipran
Low back pain and related syndromes
Paravertebral muscle and
lumbosacral joint
sprain/strain
Buttock pain : coccydynia,
piriformis syndrome
Degenerative disc disease:
herniated intervertebral
disc ,spinal stenosis
Facet syndrome , cervical
pain
Congenital abnormalities (lumbarization of S1 , spondylolysis,spondylolisthesis)
Tumors Benign (hemangiomas, osteomas, aneurysmal bone cysts)
Malignant (osteosarcomas, Ewing’s sarcoma, and giant cell tumors.)
Infections ( spinal TB)
Neuropathic pain
Pain associated with diabetic neuropathy, causalgia, phantom limbs, postherpetic neuralgia, stroke, spinal cord injury, and multiple sclerosis.
Lancinating with a burning quality
Treatment: Anticonvulsants(eg, gabapentin, pregabalin)
Antidepressants (tricyclic antidepressants)
Antiarrhythmics (mexiletine)
Α 2 -adrenergic agonists (clonidine)
Topical agents (lidocaine or capsaicin)
Analgesics (NSAIDs and opioids)
Diabetic neuropathy Symmetric ,focal /
multifocal, affecting peripheral cranial, or autonomic nerves.
Most common syndrome = peripheral polyneuropathy
Complex regional pain syndrome (CRPS) Neuropathic pain disorder
with significant autonomic features
Alterations in sweating ,color, and skin temperature, and by trophic changes in the skin, hair, or nails.
Two variants: CRPS 1, formerly known as
reflex sympathetic dystrophy (RSD),
CRPS 2, formerly known as causalgia.
Headaches
Classic headache syndromes Migraine,Tension,Cluster
Vascular disorders Temporal
arteritis,Stroke,Venousthrombosis
Neuralgias Trigeminal,Glossopharyngeal,
Occipital
Intracranial pathology Tumor, Cerebrospinal fluid
leak, Pseudomotor cerebri, Meningitis, Aneurysm
Eye disorders Glaucoma, Optic neuritis
Sinus disease Allergic, Bacterial
Temporomandibular joint disease
Dental disorders
Drug-induced Acute ingestion,Withdrawal
(eg, caffeine and alcohol)
Systemic disorders Infections
Metabolic(Hypoglycemia, Hypoxemia)
Trauma
Miscellaneous Cold stimulus (swallowing cold
liquid)
Tension headaches Migraine headaches
Tight bandlike pain or discomfort
Frontal, temporal, or occipital,
Bilateral / unilateral.
Lasting hours to days.
Associated with emotional stress or depression.
Nsaids.
Associated with photophobia,
nausea and vomiting, and
aura
Lasts 4–72 h
Family history , certain foods
menses, and sleep
deprivation
Treatment: Oxygen, Sumatriptan ,
Dihydroergotamine
Prophylactic treatment Β-adrenergic blockers, calcium
channel blockers, valproic acid,
Cluster headaches Temporal Arteritis
Unilateral and periorbital,
Occurring in clusters of one to
three attacks a day over a 4- to 8-
week period.
Burning or drilling sensation
Each episode lasts 30–120 min.
Red eye, tearing, nasal stuffiness,
ptosis,
Males (90%).
Treatments:
Oxygen and sphenopalatine block.
Prophylaxis.
Lithium and verapamil
Inflammatory disorder of
extracranial arteries.
Develops over a few hours, is
dull in quality and worse at
night and in cold weather.
Scalp
Tenderness is usually present.
Accompanied by fever, and
weight loss.
Common in older patients (>55
years), with an incidence of
about
Early diagnosis and treatment
with steroids is important
because progression can lead
Trigeminal neuralgia
Unilateral.
Electric shock quality lasting
from seconds to minutes
Facial muscle spasm middle-
aged and elderly,
Common causes : Compression of the nerve by the superior
cerebellar artery or multiple sclerosis.
Treatment Carbamazepine,phenytoin or baclofen
Glycerol injection, radiofrequency
ablation, and microvascular
decompression of the trigeminal nerve.
Cancer related pain
Give drugs at fixed
interval and by oral
Parenteral if patients
have refractory pain,
cannot take medication
orally, or poor enteral
absorption
Adjuvant drug therapy
:anti depressant
,anticonvulsants,
ziconotide (CCB)
Surgery, radiation
therapy, and
chemotherapy
ACUTE PAIN CHRONIC PAIN
Somatic
Superficial
Deep
Visceral
Localized visceral pain
Localized parietal pain
Referred visceral pain
Referred parietal pain
Conclusion
Referances
Morgan and Mikhail’s textbook of Anesthesiology,
5th edition.