Exotic Animal Musculoskeletal Diseases Flashcards
describe secondary nutritional hyperparathyroidism
- common in chelonians, lizards, and birds
- nutritional causes:
-lack of proven formulated diets, reliance on homemade diets
-rare if fed formulated diets or consume whole vertebrate prey (snakes)
-low Ca:P ration food items: insects, vegetables, fruits - environmental causes:
-insufficient UVB light (can’t do cutaneous conversion of 7-dehydrocholesterol to pre-vitamin D3)
-insufficient temperature (can’t do cutaneous thermal isomerization of pre-vitamin D3 to vitamin D3) - clinical presentation:
-limb and shell deformities, pathological fractures
-unable or unwilling to stand or move, poor balance, wing flapping
-hypocalcemia and muscle fasciculations (near terminal) - diagnosis:
-radiography: demineralization, thin cortices, periosteal reactions, pathological fractures, boney deformities
-see radiographic evidence when bone calcium <50%
-plasma total calcium and phosphorus levels change later in the course of disease; plasma ionized calcium maintained until near terminal!!
-25OHD3 blood levels:
–low = likely UVB issue
–normal = likely diet issue - critical treatment:
-if hypocalcelmic/tetany: avoid injectable calcium (risky) unless tetany (if Ca x P > = tetany)
-if hyperphosphatemia: give aluminium hydroxide (phosphate binder), do diuresis (fluid therapy to reduce phosphorous)
-assist feeding a critical care diet with calcium carbonate (safer than injectable)
-expose to unfiltered sunlight or new UVB light source - long-term treatment:
-regular exposure to sun or new UVB light source (replace every 6-9 months)
-ensure correct temperatures
-use a balanced commercial diet whenever possible for majority of diet
-select high Ca:P food items for homemade/natural diets
-use a high Ca (no phosphorous, no D3) powder to gut-load and dust all insects and dust all low Ca:P plant materials
describe fractures
use established ortho approach and principles
ask:
what is fractured? how bad? perform physical exam and radiography under sedation
-open, infected fractures typically carry poorer prognosis
-soft tissues (muscles, vessels, tendons and joints) must be appreciated and preserved for repair
-is strict cage rest or amputation better than attempting repair?
-what level of repair is required? (athletic raptor versus caged parrot = different levels of precision in wing repair)
-must know species-specific anatomy
pre, peri, and post-op support/analgesia is often challenging especially for small species
describe pathological fractures (2)
- often associated with SNHP, less commonly infection, and rarely neoplasia
- weak bones will NOT support any form of surgical implant; use coaptation!
- external coaptation must be light weight and immobilize joint above/below fracture
- remember!! correct any nutritional and lighting deficiencies that caused the pathological fracture in the first place and recommend strict cage rest
describe traumatic fractures
- acceptable bone mineralization, sharp-end boney fragments
- may still be predisposed by poor nutrition (SNHP and weakened bones), inappropriate cage design or rough handling/trauma
- used established ortho principles:
-strict cage rest
-external coaptation with strict cage rest if too small for sx
-surgical repair with strict cage rest
-amputation
describe external coaptation
light-weight cast to immobilize joint above and below
-many reptiles have SNHP: correct any nutritional and lighting deficiencies, strict cage rest
-very small exotics often too small for surgical techniques
-temporary immobilization until animal can be referred
-inexpensive option if referral not financially possible
describe the figure 8 bandage for bird
- radial/ulnar fracture without body wrap
- humeral fracture (with body wrap)
describe the ball bandage for birds
- for phalangeal fractures or pododermatitis
- use a cotton ball, tape straps from digits across the ball
- use a co-forming bandage and/or elastikon
describe external coaptation of limbs
- robert jones or modifications: difficult to get above stifle n many birds and mammals, often splints are included and use distracting tape tabs
- tape splint for small birds: layers of tape, hemostat to put pressure beside limb, apply tissue glue
describe surgical fixation of fractures
- preserve joint function and soft tissues
- usually requires specialized training and equipment so refer!!
-can use type I ESF, IM pins (K wires) with cerclage or coaptation, and microplating systems
describe shell fractures
- shell is both dermatologic (keratin) and orthopedic (bone)
- assess fracture
- delay surgical repair if contaminated (>6 hours) or infected (>24 hours): clean with irrigation and decontamination, wet-to-dry dressings, maybe surgical debridement
- many repair options: plates and screws, screws and wires, epoxy, zipties
- ziptie system: clean and score shell to improve adhesion, use baking soda and thin cyanoacrylic modeling glue to secure bases across fracture. place a ziptie through both bases and secure with a second ziptie, apply tension across site and cut second ziptie short
- dry dock aquatic turtles or the first 5-7 days to ensure waterproof seal but to prevent dehydration
-keep semi-aquatic species on soaked towels and give SQ fluids
-keep aquatic species in shallow water (with fracture above water level)
-maintain excellent hygiene
-remove after 3 months, do NOT release wild turtles with shell implants (find a rehab)
describe beak deviations and overgrowth
- common in psittacines and chelonians
- can have scissor beak: lateral deviation of rhinotheca
- can have brachygnathism: rhinotheca longer than gnathptheca
- progathism: gnathotheca longer than rhinotheca
- leads to beak overgrowth and difficulty eating
- can be due to reduced protein or reduced wear due to consumption o soft foods, hand rearing practices of psitacines (always feeding from same side), require regular trimming if change of diet/feeding insufficient
- referral options involve temporary prosthetics for re-alignment
describe beak fractures
turtles: vehicular trauma or dropped
birds: usually interspecies aggression/fighting, often with mjor loss of beak tissue
repair using epoxy, baking soda/cyanoacrylic glue, implants
prostehtics rarely last, but most learn to adjust to loss of beak if fed soft/soaked pellet diet
describe fracture/shell/beak healing
- repeat radiographs in 1-2 (M, B) or 3-4 (R) weeks to assess function and for infection
- repeat radiographs in 3 weeks (M, B), or 2-3 months (R) to assess healing
- staged reduction if possible
describe osteomyelitis and arthritis
- common in all reptiles: common in the spine in snakes and limbs/joints/skill for lizards and chelonians
- often secondary to trauma or hematogenous spread
- can be bacterial or fungal
- usually produces caseous, poorly vascularized lesions
- usually unilateral so you have a cmparison limb
- diagnosis:
-leukcytosis; heterophilia, azurophilia, monocytosis
-radiography: periosteal proliferation, loss of corticomedullary definition, osteolysis
-joints: fine needle aspiration for cytology and cultures
-bones: biopsy for histopathology and cultures
describe non-infectious arthritis
- gout: deposition of urate cyrstal in synovial joints
- pseudogout: deposition of calcium pyrophosphate in or around joints
- degenerative joint disease: usually associated with previous trauma, infection, or crystal deposition (not as common in exotics as in mammals)
