Flashcards in Pain Deck (10):
Pain pathway: fast, localized
Fibers: myelinated A delta fibers
Pathway: dorsal horn, lateral STT, brainstem reticular formation and thalamus. Projections to cortex (localization and discrimination of pain)
Pain pathway: slow
Fibers: unmyelinated C fibers
Pathway: spinal cord to anterior STT, brainstem reticular formation and thalamus. Projects to cortex. Excites Reticular Activating System - diffuse arousal for protective reactions.
Intrinsic inhibition: Gate control theory
Balance between large (A beta, A alpha) and small (A delta, C). Large fibers can interfere with transmission of small fibers at first synapse.
Intrinsic inhabitation: descending analgesics
endogenous opiates (endorphins) produced in CNS - depress pain through presynaptic inhibition.
When is pain categorized as chronic?
6 months - pathology no longer identifiable
Caused by a lesion in the CNS or PNS.
Central: post stroke (thalamic) pain, TBI, Fibromyalgia
Peripheral: CRPS, neuralgia, shingles
Complex regional pain syndrome
Characteristics: occurs after trauma and disuse, SNS involvement, disproportional pain
Acute: diffuse, severe burning, alloddynia, cool skin, swelling
Dystrophic/ middle: skin changes, cessation of hair and nail growth, muscle atrophy and osteoporosis
Atrophic/ late: decreased hypersensitivity, normal temperature, severe muscle atrophy, diffuse osteoporosis
Cause: viral, inflammation of dorsal root ganglion
Characteristics: infection can last 10 days to 5 weeks, pain can last longer