Pain and Inflammation Flashcards
Acute Pain
- Frequently results from a disease, injury, or inflammation
- Sudden onset
- Short duration (<6months)
- Resolves with Healing
Chronic Pain
- Considered a disease
- Persistent
- Continues after healing
- Resistant to majority fo medical treatments
- Can be influenced by environment and psychological factors
Nociceptive Pain
- Physiologic
- “Normal” pain transmission
- Tissue injury
- Pharmacologic management: Nonopioids, opioids, local anesthetics
Neuropathic
- Pathologic
- Abnormal processing
- Pharmacologic management: Adjuvant analgesics
Somatic Pain
- Skin, bone, muscle, soft tissue
- Well localized
- Sharp, burning, gnawing, throbbing, cramping
- Intermittent or constant
- Acute or chronic
Inflammatory Pain (Inflammatory Joint Diseases)
- Inflammatory joint diseases
- Acute or chronic
- Signs & symptoms: swelling, tenderness, deformities, limitation of motion
- Treat with anti-inflammatory meds
Visceral Pain
- Diffuse, not well localized
- Nociceptor stimulation in abdominal or thoracic organs and tissues
- Dull, aching, cramping
- Referred
Neuropathic Pain
- Injuries to peripheral pain receptors, nerves or CNS
- Pain can arise from a stimulus that usually would not cause pain
- Shooting, burning, stabbing
- Difficult to treat
Nociceptive Pain Processes
- Transduction
- Nociceptors
- Inflammatory response - Transmission
- A-Delta and C Fibers - Perception
- Higher brain structure activation - Modulation
- Neurochemicals
Transduction
- If above needed threshold, the neuron will depolarize and trigger action potential
- Release of excitatory neurotransmitters and compounds
Transmission
Action potential
A-delta
- Glutamate
C fibers
- Substance P
Dorsal root ganglia
Spinal cord
Brain
A-delta fibers
Faster transmission
Lightly myelinated
Rapid reflex withdrawal
C fibers
Slow conduction
Unmyelinated
Poorly localized pain
Aching, burning
Glutamate
Binds to N-methyl-D-aspartate (NMDA) receptor
Promotes pain transmission
Secreted in spinal cord at A-delta nerve fiber endings
Substance P
Secreted at C nerve fiber endings
Opioids block at dorsal horn
Serotonin and Norepinephrine
Suppress nociceptive transmission
Perception
Higher brain structures are activated
Brain perceives pain
Modulation
Descending neuronal pathways
Inhibit pain transmission
- Endorphins
- Serotonin
- Norepinephrine
Endogenous Analgesia System
Opioids can activate
Neuropeptides
Neuropeptides
Endorphins
Enkephalins
Dynorphins
Endorphins
Inhibit pain signal transmission
Induce euphoria
Enkephalins
Inhibit Substance P release
Modulate pain perception
Dynorphins
Produce analgesia
Opioid Receptors
Mu Receptors
Kappa Recepotrs
Delta Receptors
Mu Receptors
Analgesia
Respiratory Depression
Euphoria
Miosis
Reduced GI motility
Kappa Receptors
Analgesia
Sedation
Respiratory Depression
Dysphoria
Miosis
Delta Receptors
Analgesia
Neuropathic Pain Transmission
Damage or dysfunction of the PNS or CNS
Abnormal processing of stimulus
Absence of tissue damage and inflammation
No useful purpose
Hyper excitable nerve endings
Inflammation
Nonspecific localized reaction
Protective function
Acute Inflammation
Less than 2 weeks
Protective function
Resolves after cause is removed
Chronic Inflammation
Months to years
Not protective
Long-lasting or permanent tissue damage
Five Cardinal Signs of Inflammation
Redness
Warmth
Swelling
Pain
Loss of function
Inflammatory Response Vascular Changes
Immediate vasoconstriction, then vasodilation
Increased vascular permeability
Inflammatory Response Cellular Changes
Increased Leukocyte
Chemical Mediators
Inflammatory Mediators
Bradykinin
Histamine
Prostaglandins
Bradykinin
- Vasodilation
- Increased vascular permeanbility
- Attract neautrophils
- Associated with pain response
Histamine
- Mast Cells
- Vasodilation
- Increased capillary permeability
Prostaglandins
- Chemical mediators
- Participate in inflammatory response
- Cyclooxygenase (COX) enzymes -> metabolize arachidonic acid -> produce prostaglandins
- Sensitize pain receptors
COX-1 causes…
- Decrease gastric acid secretion
- Increased mucus production
- Maintenance of renal perfusion
- Maintenance of renal function
- Vasodilation
- Bronchodilation
- Regulates plateleet aggregation
COX-2 causes…
- Vasodilation
- Increased capillary permeability
- Edema
- Pain
- Leukocytosis
Inflammtion
Inhibiting COX-1 can cause…
- Gastric erosion
- Gastric ulceration
- Bleeding tendencies
- Renal impairment
- Protects against MI and stroke
Inhibiting COX-2 can
cause…
- Renal impairment
- Promotion of MI and stroke by suppressing vasodilation
Systemic Effects of Inflammation
Fever, leukocytosis, malaise, anorexia, sepsis
