Diagnostic analgesia Flashcards
how do local anaesthetics work?
blocking sodium channels to prevent depolarisation
what are two common local anaesthesia used in equine diagnostics?
mepivicaine
bupivicaine
when should diagnostic analgesia not be used?
suspected fractures
cellulitis
uncooperative horse
why shouldn’t diagnostic analgesia be used for cases with cellulitis?
could introduce further infection
local anaesthetics don’t worm as well because the tissue is slightly acidotic
what are some possible complications associated with diagnostic analgesia?
broken needles
severe lameness after block (flare, local reaction, synovial sepsis)
what may be a reason for poor responses to local anaesthesia?
severe pain
poor technique or inadequate volume
nerve variations
subchondral bone pain
previous neurectomy
if pain originates more proximal (from neck/back…)
neurological lameness (non-pain related lameness)
what are the possible perineurial blocks of the forelimb?
palmar digital nerve block
abaxial sesamoid nerve block
low 4 point block
high 4 point
median/ulnar
what are the possible perineurial blocks of the hindlimb?
palmar digital nerve block
abaxial sesamoid nerve block
low 6 point nerve block
high 6 point nerve block
tibial/peroneal
what are the possible synovial structures that can be blocked in the forelimb?
distal interphalangeal joint
navicular bursa
proximal interphalangeal joint
digital flexor tendon sheath
metacarpophalangeal joint
carpal joints
carpal sheath
elbow
shoulder
bicipital bursa
what are the possible synovial structures that can be blocked in the hindlimb?
distal interphalangeal joint
navicular bursa
proximal interphalangeal joint
digital flexor tendon sheath
metatarsophalangeal joint
tarsal joints
calcanea bursa
tarsal sheath
stifle
hip
what is usually the first block done in the forelimb?
palmar digital nerve block
what is usually the first block done in the hindlimb?
abaxial sesamoid nerve block
where is the site for a palmar digital nerve block?
just proximal to collateral cartilage abaxial to edge of DDFT (palpate neurovascular bundle then place needle angled distally over bundle)
is the palmar digital nerve block done with the horse weightbearing or not?
non-weightbearing
what volume of local is used for palmar digital nerve block?
1.5-2ml (medially and laterally)