Pain in Animals Flashcards
What is pain?
Unpleasant emotional and sensory experience from actual or potential tissue damage
What is a nociceptor?
A pain receptor with free nerve ending of primary sensory neurons; A-delta or C fiber
What is nociception?
Activation of nociceptors by noxious stimuli
What is analgesia?
The absence of pain in the presence of stimuli that would normally be painful
What are analgesics?
Drugs that produce analgesia
What is allodynia?
A painful response to a nonpainful stimulus
What is hyperalgesia?
An abnormally heightened sensitivity to pain
What is hypoalgesia?
A decreased sensitivity to painful stimulation
What is a neurotransmitter?
A substance released from a nerve ending, binds to a receptor, and causes a response
Does pain occur quickly or slowly with A-delta fibers?
Fast
Does pain occur quickly or slowly with C fibers?
Slow
What is the pathophysiology of pain?
Nociceptor activation
Tissue trauma causing a release of inflammatory mediators
What are the steps of pain processing?
Transduction Transmission Modulation Perception Projection
What is transduction?
The process that involves the translation of a noxious stimulus into electrical signals at the sensory nerve ending
What is transmission?
The process of sending sensory impulses from the peripheral pain receptors to the spinal cord
What is projection?
Signals reaching the dorsal horn of the spinal cord synapse in laminae I, II, and V, then may or may not cross the spinal cord and continue to travel along second order neurons to higher areas of the CNS
A number of excitatory and inhibitory neurotransmitters are responsible for affecting signal transmission
What is modulation?
The modification of nociceptive transmission
What is perception?
Occurs once the transmitted signals reach the higher centers of CNS
Integration, processing, and recognition occurs
Why is pain difficult to manage?
Neurons exhibit plasticity
What are characteristics nociceptors acquire in the presence of inflammation?
Begin to discharge spontaneously
Threshold for activation is decreased
Decreased stimulus require to produce a response
What is the neurotransmitter released from C-fibers?
Glutamate
What does glutamate do?
Acts on NMDA receptors causing a change in the post-synaptic neuron causing it to respond more strongly to all input
What is acute pain?
< 2 weeks duration
What causes chronic pain?
Plasticity/sensitizaton
Arthritis, cancer, neuropathic
What are causes of inflammatory pain?
Tissue trauma
Surgery, burns, injury
Nocicpetive pain
What is the cause of neuropathic pain?
Nerve injury
What are causes of somatic pain?
Inflammatory pain (bone, muscle skin, peritoneum) Sharp, stabbing, well localized A-delta nociceptors
What are causes of visceral pain?
Distention, ischemia, smooth muscle spasm, stretching of ligaments
Dull, aching, radiate to other area
C fiber and A-delta fibers
What is the treatment for mild pain?
Responds to no or minimal drug prevention
What is the treatment for moderate severity?
Needs significant analgesic intervention; mulitmodal
Why treat pain?
Prevent or minimize suffering
Prevent pathologic consequences
What are signs of pain across all species?
Inappetence
Abnormal behavior
Abnormal posture
Facial expression
What are signs of pain in birds?
Reluctant to move
Ruffled feathers
Aggression
Feather picking
What are signs of pain in cattle?
Grunt, bellow Anti-social behavior Decreased production Painful expression Bruxism
What are signs of pain in cats?
Hide, reluctant to move No grooming Abnormal posture Aggression Tachycardia