Reptiles 4 Non-Infectious Diseases Flashcards
Most common presentation of pet reptiles
Anorexia
Anorexia in reptiles
- common?
- specificity?
> what should we check?
- Tx?
- Most common presentation of pet reptiles
<> - Non-specific:
- Any disease will cause anorexia
- Check husbandry
- Check the type of food offered
- Do general workup (i.e., physical examination, blood work, imaging, fecal testing)
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Treatment can be long - Supportive care
- Assisted feeding
> Esophagostomy tubes in chelonians
Metabolic Bone Disease
- categories we see
- Nutritional secondary hyperparathyroidism
- Renal secondary hyperparathyroidism
Metabolic Bone Disease
* Nutritional secondary hyperparathyroidism
> Causes
- Lack of UVB
- Improper Ca:P ratio (2:1) in diet
- Ca deficiencies
Reptile Vitamin D3 metabolism
- In most snakes, crocodilians, some chelonians, and some amphibians, a nocturnal lifestyle or ingestion of whole prey has allowed vitamin D3 to be primarily or completely obtained from the diet.
- However, diurnal, insectivorous, or herbivorous reptiles (particularly lizards, some chelonians, and some amphibians) require UVB exposure to activate the cholecalciferol pathway.
- Under natural conditions, reptiles synthesize vitamin D3 when exposed to sunlight.
- UV light in the spectrum (290–320 nm) reacts to convert cholesterol to the inactive
form of vitamin D3 in the skin; this vitamin D3 is then converted to 1,25-
dihydroxycholecalciferol (calcitriol) through the liver and kidneys. - Calcitriol is then used to facilitate the absorption of calcium from the intestinal
tract. - In captivity, an alternative to natural sunlight that mimics the spectrum of natural
light is required; these UV lights are often a poor replacement for natural sunlight,
and natural sunlight should be provided whenever possible. - When an animal cannot be provided with proper exposure to UV light, vitamin D3
supplementation can be considered; however, risks associated with hypervitaminosis D.
Metabolic Bone Disease
- signs
- Bone malformations
- Osteomalacia
- Fibrous osteodystrophy
- Pathologic fractures
- Stunting
- Neurological signs
- Muscular signs
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clinical cases of nutritional secondary hyperparathyroidism
> what happens / pathogenesis
> why do we see the signs that we do?
- In clinical cases of nutritional secondary hyperparathyroidism, excessive production of parathyroid hormone (PTH) from the parathyroid gland occurs in response to the diet or husbandry-related hypocalcemia.
- PTH increases blood calcium by stimulating bone resorption and renal tubular reabsorption of calcium; also stimulates the formation of 1,25- dihydroxycholecalciferol, which increases the absorption of intestinal calcium.
- Phosphorus excretion by the kidney is increased.
- Calcium deficiency can increase the threshold potential of nerves and muscles,
causing partial depolarization; spastic tremors and twitching of the digits.
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Signs - Bone malformations
- Osteomalacia
- Fibrous osteodystrophy
- Pathologic fractures
- Stunting
- Neurological signs
- Muscular signs
Metabolic Bone Disease diagnostics
- Total calcium
- Phosphorus
- Ionized calcium
- Radiographs
<><> - Also renal with the Ca:P ratio.
Metabolic Bone Disease Tx
Improve husbandry:
* UVB
* Dietary calcium supplementation
* Temperature
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Medical treatment
* Injectable calcium if iCa low (seizuring, tremors)
* Daily oral calcium
* Vitamin D3 weekly injections or oral supplementation
Metabolic Bone Disease
* Renal secondary hyperparathyroidism
- common in what animals?
> what do they need
- what is the problem with the kidneys here, and result?
- Common in chameleons
<> - Need high humidity
- Dripping water/misting/fogging for drinking
<> - Failing kidneys do not convert vitamin D3 to active form (calcitriol), and do not excrete phosphorus.
Hypovitaminosis A
- mostly in what reptiles? why? what do they require?
- Mostlyin carnivorous/insectivorous reptiles
- Cannot convert β-carotenes to vitamin A
- Require supplement with pre-formed vitamin A
Hypovitaminosis A
- clinical signs
- Blepharedema, lachrymal and periocular gland distention
> Leopard geckos
> Red-eared sliders - Squamous metaplasia
- Gular edema in chameleons
- Immune suppression
Hypovitaminosis A
- properties of vitamin A
> functions
> forms
> enzymes for use?
> common in what animals? why?
- Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), and retinoic acid. Vitamin A has multiple functions: it is essential for embryo development and growth, for maintenance of the immune system, and for vision, where it combines with the protein opsin to form rhodopsin – the light- absorbing molecule necessary for both low-light (scotopic vision) and color vision.
- Vitamin A occurs as two principal forms in foods: a) retinol (vitamin A1), found in animal-sourced foods, either as retinol or bound to a fatty acid to become a retinyl ester, and b) the carotenoids, alpha-carotene, β-carotene, gamma-carotene, and the xanthophyll beta-cryptoxanthin (all of which contain β-ionone rings), that function as provitamin A in animals which possess the enzymes that cleave and convert provitamin carotenoids to retinal and then to retinol.
- Herbivore and omnivore species possess this enzyme; some carnivore species lack this enzyme (but receive retinol in their animal-sourced diet).
- Vitamin A deficiency is common in all captive insectivorous reptiles, including leopard geckos, chameleons, and anoles. It is thought to result from dietary deficiency since a) it is unknown if insectivorous lizards can synthesize vitamin A from carotenoids in their diet, b) feeder insects are generally deficient in vitamin A and often receive vitamin A-deficient diets, and c) many food manufacturers omit vitamin A and substitute β-carotene in reptile multivitamins because of misinformation that vitamin A is toxic to insectivores.
Hypovitaminosis A Dx, Tx
Diagnosis:
* History
* Response to treatment
* Blood and liver vitamin A levels
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Treatment:
* Slow response
* Injectable (once) or oral vitamin A
* Be cautious about hypervitaminosis A
Hepatic Lipidosis
- is it common? in what animals?
- Very common
- Bearded dragons
- Female reptiles
Hepatic Lipidosis causes
- Accumulation of triglycerides in the liver
- Likely related to diet
- Estrogen-induced lipogenesis in lots of reptiles (like birds, but more extreme)
Hepatic Lipidosis Dx
Biochemistry:
* Unreliable
* Elevation in bile acids
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Imaging
* Hyperechoic liver on ultrasound
* Low density on CT
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Liverbiopsy
* Coelioscopy
Hepatic Lipidosis Tx
- Improve husbandry
- Improve diet
> Low fat invertebrates
> Switch to primary herbivorous - Chronic assisted feeding
- Drugs–currently being studied
> Gemfibrozil
> Carnitine
Constipation / Impaction
- common in what species? what causes this?
- Dx
- Tx
Common in all species
* Fecalith
* Undigested food
* Substrate, rocks
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Diagnosis
* Coelomic palpation
* Diagnostic imaging
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Treatment
* Enema
* Soaking
* Correct husbandry
* Vibration
* Enterotomy (uncommon)
Cloacal Prolapse
* What can be included in the prolapse?
- Cloaca (coprodeum)
- Rectum/colon
- Oviduct
- Phallus/hemipenes
- Bladder (chelonians)
Cloacal Prolapse
* Common causes
- Intestinal diseases
> GI parasitism
> Enteritis
> Fecalith/impaction - Husbandry (calcium)
- Improper diet
- Straining
- Coelomic disease
Cloacal Prolapse Tx options
Medical treatment
* Depends on the cause
* Reduction + transverse cloacal sutures
* Supportive care
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Surgical treatment
* Coeliotomy
> Colonic prolapse > intestinal resection and anastomosis, or reduction and pexy
> Oviductal prolapse > hysterectomy
Dysecdysis
- what is this?
- causes and risk factors
- Shedding disorders
<><><><> - Improper humidity
> Background humidity
> Humidity boxes - Other environmental variables
> Temperature
> Nutrition - Skin diseases and wounds
- Lack of rocks or similar items in enclosures
- Neurological disorders
- Skin trauma from manual helping from owner during shedding
Dysecdysis in snakes
- common issues
- Shed spectacle too
> Can be retained with dysecdysis - Blue eyes during shedding
- Normally anorexic
Dysecdysis in lizards
- common issues
- May develop constricting bands around toes and tip of tail > leads to ischemia and loss
Dysecdysis treatment
- Soaking (plain warm
water) - Careful manual removal with lube (toes and tail tip)
- Correct husbandry and wait for the next shed
- Be careful with spectacles
> Can inject fluid or eye lube between old and new spectacle with a small catheter
Dermatitis
- what type is common?
- related to what, often?
Fungal dermatitis common
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Environmental related
* Thermal burns
* Poor water quality
* Ventral dermatitis of snakes
Wounds
- common ones we see?
> how may they arise?
Rostral abrasion
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Prey bites
* Should not feed live preys to snakes
* Invertebrates may also inflict bites if present for extended periods
Shell Fracture
- stabilization
- prognosis, complications
Patient stabilization:
* Fluids
* Analgesics
* Antibiotics
* Wound management
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Bad prognosis
* Multiple or very extensive
fractures
* Spine is affected
> Some species have some regenerative capacity
* Organ trauma, punctures, exteriorization
* Exposed/punctured lungs
* Pelvic fractures
Shell fracture
* Fracture reduction and fixation methods
- Screws (drill shallow holes first) and wires
- Fabric hooks, epoxy glue (wait 24h), and wires
- Dental acrylic sheets (3M Triad-TranSheet®)
- Wires; tape and Super Glue
Pyramidal shell growth
> risk factors?
- Inadequate diet (high proteins, overfeeding)
- Low humidity
- Metabolic bone disease
- Unsure etiology
Soft shell
- how does this arise?
- Metabolic bone disease
Distorted shell
- how does this arise
- Metabolic bone disease
- Previous trauma
- Developmental abnormalities
Discoloured shell
- causes
- Dermatitis (bacterial, fungal)
- Algal growth
- Previous trauma
Tail Necrosis
- causes
- Tail autotomy
- Tail bandages
- Ascending avascular necrosis
- Trauma (slapping their tails)
- Dysecdysis, nutritional issues, husbandry issues
- Infection (bacterial, fungal)
Tail Necrosis Tx
- Tailamputation
> Leave skin unclosed for normal regeneration in autotomizing species
Cardiac Diseases we commonly see in reptiles
- Mild valvular regurgitation on echocardiography is normal in many reptiles
- Congestive heart failure
- Pericardial effusion
- Atherosclerosis
Congestive heart failure more common in what species? secondary to what?
- Snakes most commonly
- Frequently secondary to valvular endocarditis
- Cardiomyopathy and valvular insufficiencies
Pericardial effusion common in what species
- Bearded dragons
- Mild amount can be normal
Atherosclerosis common in what animals
- Bearded dragons
Arterial Aneurysm common in what species?
where?
- Dx?
- Tx?
Bearded dragons
* Carotid arteries
* Head, neck, and inside the throat
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* Diagnosis
> FNA > blood
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* No effective treatment
Phallus/Hemipenes Prolapse
- is it common
- mild vs severe Tx
- Common
- If mild, can replace and apply 2 transverse sutures
- If severe or recurrent, phallic/hemipenis amputation is recommended
Follicular Stasis
- another name? what is this?
- common? causes?
- imaging, and issues?
- Also called pre-ovulatory dystocia
> Inability to ovulate or resorb oocytes - Common in some lizards and turtles
> May be caused by inappropriate captive seasonality, photoperiod, husbandry, poor substrate (cannot dig), stress, diseases - Eggshells are poorly calcified in squamates, and more calcified in chelonians
> Hard to differentiate follicles from eggs on x-rays
Follicular Stasis Dx
- feel?
- radiographs in squamates: eggs vs follicle appearance
- Coelomic palpation
<> - Radiographs in squamates:
- Follicles: round, in clusters, dorsal
- Eggs: oval, more caudal
Follicular Stasis
- Dx w/ ultrasound - what can we see?
Ultrasound
* Heterogeneous echogenicity and loss of structure indicates oophoritis, old follicles
* Useful for staging and monitoring follicles
Follicular Stasis Tx
- Correct husbandry and wait
- Coeliotomy and ovariectomy
Dystocia
- hard to differentiate from what?
- causes
- Hard to differentiate from postponed laying
<>
Causes: - Similar to follicular stasis
- Oviductal diseases
- Egg malformations
- Pelvic/bone malformations
Dystocia medical Tx options
- Correct husbandry
- Provide hiding spots and deep substrate
- Oxytocin in chelonians (does not work in squamates)
Dystocia surgical treatment options
- Percloacal ovocentesis
- Coeliotomy
Gout
- what is it? types? contributing factors?
- Dx
- Tx
Deposition of uric acid in tissue
* Visceral and articular gout
* Hyperuricemia
* Renal disease/dehydration
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Diagnosis
* FNA (cytology, polarized light)
* Histopathology
* Blood uric acid
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Treatment
* Guarded to poor prognosis
* Fluids
* Surgical removal of tophi
Urolithiasis
- what are they, what species do we see them in?
- main cause?
- Dx
- Tx
- Large uric acid/electrolytes calculi in the bladder
> Tortoises
> Desert lizard species - > Chuckwalla
- > Uromastyx spp.
<><> - Chronic dehydration
<><> - Diagnosis
> Typically, radiopaque
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Treatment: - If in cloaca, drill and forceps
- Cystotomy
- Bladder excision for recurrent issues
Bearded Dragon Oncology
- what cancers are we worried about? where anatomically?
- Leukemia
> Typically, monocytic or myeloid
<><> - Gastric neuroendocrine carcinoma
> GI signs and hyperglycemia
<><> - Squamous cell carcinoma
> Typically, on the head
> May be associated with UV overexposure
Oncology – Other Reptiles that are not bearded dragons
- what are we worried about?
Skin tumors and external masses
* Squamous cell carcinoma
* Soft tissue sarcomas
* Iridophoromas (chameleons)
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Tumours are common in snakes
* Coelomic
> Renal adenocarcinoma
* Soft tissue sarcomas
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Lymphosarcoma
Ocular Diseases we see in reptiles
- Spectacle retention (dysecdysis)
- Subspectacular abscesses
- Pseudobuphthalmia in snakes
- Blepharedema (vitamin A)
Toxicoses we more commonly see, and in what animals
Ivermectin
* Chelonians
* Some chameleons and skinks
* Mild in ball pythons
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Enrofloxacin
* Local tissue necrosis, should not be given IM
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Metronidazole
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Triazole antifungals
* Toxicities vary, but are more common than in birds
* Itraconazole toxic in a number of reptiles
* Voriconazole is toxic in some snakes
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Vitamin A and D
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Heavy metals
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Do not use medicated baths in general
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Lots of potential toxicities with numerous drugs as for other animals. Only reported those that are particularly common in reptiles.
