Herp Dermatology Flashcards
1
Q
Describe the anatomy of reptile skin, starting from most superficial layer to the deepest.
What is the difference between alpha and beta keratin? Where are each located?
What glands do reptiles have in their skin?
What species of snakes can sense infrared? How do their pits differ?
Describe the role the parietal eye plays in reptiles.
What are the four types of chromatophores in the dermis?
A
Anatomy
- Two layers - outer epidermis and underlying dermis
- Epidermis - covered by either α- or β-keratin
- β-keratin - durable, lightweight material critical for increasing mechanical resistance of epidermis
- Epidermis - covered by either α- or β-keratin
- From superficial to deep:
- Outer epidermal generation
- Oberhautchen: outermost portion of β-layer, characterized by serrations, surface ornaments, and pits
- ß-keratin: inelastic, tough, stratified epithelial layer, composed primarily of β-keratin (the hinge area between scales is lacking this layer)
- Mesostratum: transitional cells between α- and β-layers
- α-keratin: soft, flexible epithelial layer composed primarily of α-keratin
- Lacunar stratum: innermost layer of outer portion of skin, tightly adhered to newly forming oberhautchen
- Inner epidermal generation
- Presumptive β-keratin layer
- Presumptive meso layer
- Presumptive α-keratin layer
- Stratum germinativum: deepest basal layer of progenitor columnar epithelium
- Outer epidermal generation
- β-keratin – scales
- α-keratin – softer between scales
- Few glands in skin
- Musk glands adjacent to cloaca in some species
- Crocodilians – medial to dentary bone
- Mental or chin glands – some chelonians
- Specialized glands at angle of jaw – chameleons function unknown
- Musk glands adjacent to cloaca in some species
- Prominent prefemoral or precloacal pores in males (some species)
- Secrete pheromones
- Thick waxy substance aids in adhering male to female
- Paired Rathke’s gland of chelonians
- Secretory gland
- Located between dorsal corners of bridge/carapace junction, caudal to foreleg and cranial to hind leg
- Used for defense against predators - emits foul-smelling liquid when animal has been disturbed (some species)
- Skin generally dry
- Integumentary sense organs - located in the postcranial and ventral scales, described in some crocodilian species
- Boas, pythons, and vipers - possess specialized pits utilized to sense infrared radiation to aid in location of prey
- Pythons and boas - located along edges of labial scales, cover most of upper or lower lip
- Vipers - located bilaterally, midway between nostril and eye, focused in forward direction
- Parietal eye
- Unique to lizards and tuatara (most developed in this species)
- On dorsal head
- Rudimentary lens and retina
- Relay environmental cues to pineal gland controls hormone production and influences thermoregulation, also helps with spatial relations in some species
- Dermis
- Highly vascular
- Contains sensory tissue, chromatophores and osteoderms in some species
- 4 types of chromatophores
- Melanophores - contain melanin
- Erythrophores - contain pteridines and carotenoids
- Xanthophores - contain pteridines and carotenoids
- Iridophores – contain reflecting platelets of guanine, adenine, hypoxanthine, and uric acid
- 4 types of chromatophores
- Osteoderms - predominately comprised of osseous material
2
Q
Describe the physiology of reptile skin.
What is the process of ecdysis?
What factors influence the timing of ecdysis?
How does it vary by reptile taxa?
What are the stages of ecdysis?
How do reptiles change the color of their skin?
Describe the rain harvesting thorny devils can do with their skin.
A
Physiology
- Ecdysis
- Under hormonal control from pituitary-thyroid axis
- Influenced by age, temperature, UV-B exposure, skin trauma, frequency/amount of food
- Species variation:
- Chelonians and archosaurs (crocodiles and birds) – process continuous
- Lepidosaurs (lizards, amphisbaenids, sphenodontids, and snakes) and some chelonians – process discontinuous, cyclical
- Process:
- Resting stage (consisting of three subdivisions) followed by five stages of renewal
- Resting – follows slough, normal state, minimal cellular activity
- Renewal - cellular divisions in epidermis, generation of new skin
- Two layers are separated by enzyme-induced digestion of bonds holding old skin to new
- Resting stage (consisting of three subdivisions) followed by five stages of renewal
- Physiological color change - achieved by repositioning of pigment granules within cytoplasm of chromatophores by microscopic intracellular microorganelles
- Nervous and endocrine control
- Examples:
- Old world chameleon - sympathetic nervous regulation
- Green anole – hormonal control, melanocyte-stimulating hormone (MSH)
- Horned lizard – both hormonal and nervous control
- Some desert species skin helps direct water for hydration
- Thorny devils - interscalar capillary channels, directs water toward the labial scales
- Aka “rain harvesting”
- Thorny devils - interscalar capillary channels, directs water toward the labial scales
3
Q
Describe the viruses affecting reptile skin.
Poxviridae
- What are the clinical signs with chelonian poxviruses?
- What about crocodilian poxvirus?
- What are the lesions with tegu poxvirus?
Iridoviridae
- How does ranavirus affect the skin?
Herpesviridae
- What is the virus that causes grey patch disease in sea turtles?
- What virus causes fibropapillomatosis?
- What are the lesions associated with crocodilian herpesviruses (CrHV-1,2,3)?
Papillomaviridae
- What are the lesions associated with Chelonian papilloma virus?
Flaviviridae
- What are the lesions associated with West Nile Virus in crocodilians?
A
4
Q
What are some of the common bacteria causing skin lesions in reptiles?
What bacteria are commonly transmitted with bites or scratches?
What causes scale rot in reptiles?
Why should bearded dragons and uromastyx not be housed together? What are the clinical signs of this disease - which species are affected?
A
- Bacterial
- Aeromonas, Pseudomonas, Flavobacterium, Staphylococcus, Salmonella, Morganella, Edwardsiella, Klebsiella, Micrococcus, Neisseria, Proteus, Serratia, and Enterobacter spp. commonly isolated from dermal lesions in reptiles
-
Bacteroides, Fusobacterium, Peptostreptococcus and Clostridium spp. (anaerobes) part of normal microbiota in reptiles
- can cause dermal disease following bite lesions, scratches, or septicemia
- Actinobacteria - can cause primary dermatological disease in many taxa
- Dermatophilus congolensis - cutaneous ulceration, hyperkeratosis, necrosis, and subcutaneous abscesses in lizards, snakes, and saltwater crocodiles
- Austwickia chelonae - cultured from skin lesions in chelonians
-
Mycobacterium spp
- granulomatous inflammation of the skin, can be systemic
- “scale rot” – aka necrotizing dermatitis, blister disease
- Subcutaneous erythema, fluid-filled vesicles, and bullae typically on ventrum
- Mostly seen in snakes
- Causes - poor ventilation, excessively high humidity levels, inadequate hygiene
- Devrieseasis - dermatological disease characterized by chronic proliferative dermatitis and septicemia, especially in desert-dwelling and dry land lizard species
-
Devriesea agamarum
- Long-term environmental survival of bacteria
- Asymptomatic carriers - bearded dragons
- High morbidity, low mortality - saurian taxa such as dab lizards (Uromastyx spp.)
- Chronic subcutaneous abscesses and septicemia
- High mortality in collared lizards and Agamid lizards
-
Devriesea agamarum
5
Q
What are the organisms that previously made up CANV in reptiles?
What lesions do they cause?
How are they diagnosed and treated?
A
- Fungal
- CANV-complex -> obligate fungal pathogens
-
Nannizziopsis spp - saurians and crocodiles
-
Nannizziopsis guarroi - severe dermatomycosis in inland bearded dragons and green iguanas
- Pericloacal and mandibular region – common site of lesions
-
Nannizziopsis guarroi - severe dermatomycosis in inland bearded dragons and green iguanas
- Ophidiomyces with Ophidiomyces ophiodiicola – snake fungal disease
- Paranannizziopsis spp. - squamates and tuataras
- Localized, crusty, yellow to brown skin lesions, vesicles, and hyperkeratotic lesions, can progress to necrosis of extensive areas of skin
- Diagnosis – fungal culture, if not known primary pathogen interpret w/ caution
- Treatment – triazole antifungals, debridement of lesions, topical terbinafine or chlorhex, monitor for drug toxicity
-
Nannizziopsis spp - saurians and crocodiles
- CANV-complex -> obligate fungal pathogens
6
Q
Describe reptile abscesses.
THey are typically caused by what organisms?
What is cellulitis?
What species are prone to pododermatitis? What are some risk factors?
A
Abscesses
- Mostly gram-negative bacteria
- May be local or hematogenous spread
- Often well encapsulated
- If Salmonella or Mycobacterium spp. isolated from dermal abscesses or granulomas, the presence of concurrent infectious osteoarthritis, osteomyelitis, or soft tissue abscesses should be considered
- Cellulitis – deep suppurative infection
- Characterized by dissemination through the skin
- Swelling often soft and fluid can often be aspirated
- Pododermatitis and abscessation of feet
- Often seen in large saurians such as monitors, iguanas, and chelonians
- Risk factors – excessive humidity, abrasive surfaces
- Can get secondary osteomyelitis with deep infections
- Tx – poor penetration of abx, excision or marsupialization is ideal
7
Q
What is the most common reptile mite?
Which stage is parasitic?
What are the typical clinical signs?
Where are the mites commonly seen?
How are these cases treated?
A
Parasitic disease
- Can be vectors for transmission of serious infectious diseases such as arenavirus
- Ticks and mites common, leeches in aquatic turtles
- Variable host specificity depending on species
-
Ophionyssus natricis – snake mite
- Five life periods: egg, larva, protonymph, deutonymph, adult
- Only protonymph and adult are parasitic, feeding on the blood, other stages are free-living in environment
- Clinical signs – non-specific, maybe behavioral changes and rubbing
- May see white powdery dots – mite feces
- Dull scales/skin, dysecdysis possible
- Severe infections can cause sepsis, anemia, anorexia and lethargy
- Predilection for periocular region, folds of skin under chin, around cloaca, in thermosensory pits of snakes, and in axillae and tympanic recesses of lizards
- If sending to parasitologist – store in 70% to 90% ethanol
- Tx – host + environment
- Fipronil or pyrethroid spray most effective
- Ivermectin toxic to chelonians, maybe crocodilians
- Tx env - pyrethrin, pyrethroid, carbaryl, or organophosphate, boiling water or washing 3% bleach solution
8
Q
Describe the noninfectious skin diseases of reptiles.
What are some causes of dysecdysis? How is it managed?
Why are burns such a problem?
What are some common nutritional dermatoses? What clinical signs are typiclaly seen with each?
What are some of the common neoplasia of reptile skin?
A
Non-infectious
- Dysecdysis
- Possible causes - inappropriate environmental conditions, nutritional deficiencies, dehydration, and traumatic injuries, infectious disease affecting skin
- Dehydration – no fluid to separate layers
- Hypoproteinemia – interfere with enzyme production for fission layer
- Tx – increase environmental humidity, soaking may help
- Possible causes - inappropriate environmental conditions, nutritional deficiencies, dehydration, and traumatic injuries, infectious disease affecting skin
- Burns
- Cause – provision of inappropriate heat sources (direct contact with hot rocks or mats), heat lamps too close
- Tx – wound management, fluids (counteract significant fluid loss and electrolyte imbalances), feeding (counteract resultant hypoproteinemia from protein loss), +/- antibiotics, analgesia
- Prey bites
- Rostral abrasion
- Commonly caused by rubbing on glass or wire surfaces
- Can get deep infections
- Nutritional dermatoses
- Signs - abnormal color changes, dysecdysis, abrasions, or keratinization disorders resulting in an abnormal appearance to skin texture
- Hypovitaminosis A - primarily recognized as a disease of chelonians, sometimes lizards
- Signs - palpebral edema, conjunctivitis, cheilitis, aural abscesses
- Impaction of precloacal and femoral pores, hemipene plugs with secondary infection in lizards
- Susceptible to secondary bacterial and mycotic infection
- Tx – vitamin A supplementation but careful dosing
- Doses of 2000 to 5000 IU/kg vitamin A are considered safe
- Improve nutrition and oral supplementation
- Signs - palpebral edema, conjunctivitis, cheilitis, aural abscesses
- Vitamin C deficiency in snakes – fragile skin, easily tearing skin
- Steatitis of skin with necrosis and sloughing observed in piscivorous reptiles fed diets high in polyunsaturated fats, especially when rancid
- Neoplasia
- Fibrosarcomas, liposarcomas, chromatophoromas, epitheliomas, mast cell tumors, and squamous cell carcinomas have been diagnosed
- Chromatophoromas - classified as melanophoromas or melanomas, iridophoromas, xanthophoromas, erythrophoromas or mixed
- High incidence – especially diurnal species
- Risk factor - continuous exposure to high doses of artificial UV radiation
- Most cutaneous neoplasia in reptiles locally aggressive and less metastatic
- Mast cell tumors, SCC, and melanophormas may show a multicentric appearance
- Many reptile skin neoplasms show a moderate to high recurrence rate
9
Q
Describe integumentary surgery in reptile species.
What surgical site preparation is needed.
Describe the ideal incision process and closing technique.
When should sutures be removed?
How well do reptiles do with open wounds?
A
MARMS – 96. Integument Sx
Surgical Site Preparation
- Chlorhexidine or povidone iodine for sterile prep
- Sterile toothbrush or hand brush helps clean between scales
- Final alcohol wipe following prep
- Clear, adhesive plastic drapes - allow better visualization of patient, waterproof, and do not require the use of towel clamps
Skin Incisions and Wound Closure
- Avoid cutting scales and osteoderms in incision
- Tent skin and make stab incision
- Scissors or upturned scalpel blade to extend incision
- Close incisions in everting pattern – horizontal mattress sutures
- Skin edges tend to curl inward
- Suitable suture material - nonabsorbable (monofilament nylon, Ethilon) or absorbable suture (poliglecaprone 25, Monocryl)
- Avoid braided materials that allow wicking or chromic catgut that causes intense inflammation
- Suture removal is generally 6 to 8 weeks postoperatively
- Edysis may cause premature suture loss, dysecdysis expected at site which often resolves after 1-3 shed cycles
- Skin staples and skin glue (small incisions) can also be used
Subcutaneous masses (ABSCESSES, PARASITIC CYSTS, AND NEOPLASMS)
- Abscesses – typically firm, rarely liquid
- Excise completely if possible
- Consider submitting all masses for histo path to differentiate
Open Wound Management
- Reptiles do well with this
- Debride and thoroughly lavage (sterile saline)
- Addition of antiseptics has not been shown to be beneficial, may be cytotoxic and may inhibit wound healing
- Topical wound coverings (hydroscopic gels, antibiotic ointments, silver cream, and honey) can be utilized to promote wound healing and decrease the risks of post-debridement infection
- Low-level laser therapy helpful
10
Q
What types of thermal burns are common in reptiles?
How do they occur?
What is treatment usually consist of? What are some common sequelae?
What are some potential predisposing factors for abscesses in reptiles?
How are abscesses treated?
A
MARMS – 170. Thermal Burns
- Thermal burns - injuries caused by direct or indirect contact with heated objects or excessive infrared radiation
- Common causes - unguarded heat bulbs, hot rocks, heat mats
- Treatment - wound management
- Correct fluid loss
- Cleaning - dilute chlorhexidine, iodine
- Husbandry changes - remove source of burn, keep in clean environment
- Enzyme ointments - necrotic wounds, stimulate secondary healing
- wet-to -dry bandage
- If surgical debridement needed, consider antimicrobials
- Analgesia
- Low-level laser therapy
- Recurrent dysecdysis common
- Prognosis depends on severity
- Prevention - discuss appropriate husbandry with clients
MARMS – 138. Abscesses
- Some people call reptile abscesses fibriscesses because they are inspirssated and have a fibrous capsule
- Abscesses can occur from trauma or hypovitaminosis A (epithelial metaplasia)
- Samples for microbiology should be taken from the inner lining of the fibrous capsule
- Recommended treatment = surgical removal +/- topical antibiotics
- Systemic antibiotics are rarely useful
11
Q
Describe the management of acariasis in reptiles.
What is the snake mite? What is the lizard mite?
What are the clinical signs of an animal with acriasis?
How is this treated?
How shoudl the environment be cleaned?
What drugs should NOT be used?
What animals cannot receive topical ivermectin?
A
MARMS – 139. Acariasis
- Acariasis = Infestation with ticks and mites
- Associated with unsanitary conditions, poor husbandry practices, and recent imports of infested animals
- Linked to itching, discomfort, dermatitis, anemia, failure to thrive, anemia, transmission of blood-borne disease
-
Ophionyssus natricis
- Parasitiformes, Macronyssidae
- Snake mite – can also infect lizards and turtles
- Most common mite found in reptiles
- Black in color
-
Ophinyssus acertinus
- Lizard mite
- Usually red and larger than snake mite
- Trombiculid mites
- “Chigger mites”
- Only parasitic in larval form
- Soft- and hard-bodied ticks
- Found in snakes, lizards, and turtles
- May cause anemia and introduce toxins with their bites
- Potential to transmit microbial diseases
-
Signs of acariasis
- Anorexia, dermatitis, pruritus, anemia, septicemia, dysecdysis (persistent or recurrent in snakes), retained eye caps, dehydration, failure to thrive, transmission of blood-borne pathogens
- Behavioral changes
- Snakes may remain coiled in water bowls and soak for extended periods
- Rubbing on cage furniture
- Hyperactivity
- Skin of mite-infested reptiles dull, lackluster, “dirty” appearance due to white “dustlike” mite waste material
- Common areas for mites - skin folds under chin, under scutes, in periocular region around eyes, inside skin folds around cloaca, and tympanic recesses in lizards
- Skin - hyperemic, edematous, and infiltrated with heterophils, lymphocytes, and plasma cells
-
Mite treatment:
- Quarantine new animals at least 3 months
- Most important management and control method
- Permethrin - 0.5% permethrin spray (Provent-a-Mite)
- Preferred treatment
- Qait until dried before placing animal back in cage
- Only product licensed as an acaracide for reptiles
- Quarantine new animals at least 3 months
-
Sanitation/cleaning
- Killed by hot water >122°F (750°C)
- Cages, shelves, and lids should be cleaned weekly
- Topical ivermectin
- 0.5 mL of ivermectin (10 mg/mL) added to 1 quart tap water
- Applied to cage and surroundings
- Avoid spraying into water bowl
- Sprayed or wiped on snakes and lizards
- Weekly or every other week treatments for 6-8 weeks
- Never use on or around chelonians or indigo snakes
- Fipronil
- 0.29% fipronil spray (Frontline)
- Resmethrin II
- 0.35% remethrin
- Permectin II
- 10% permethrin diluted to 1% in tap water used as spray
- Dilute pyrethrin
- 0.03% dilute pyrethrin
- Imidacloprid plus moxidectin
- Commercial Imidacloprid (100 g/L) plus moxidectin (25 g/L)
- Biologic control of mite
- predatory mites
-
NOT recommended
- Chlorinated hydrocarbons (DDT) - toxicity
- Organophosphates (Trichlorfon) - toxicity
- 5% Sevin Dust - toxicity
- Dichlorvos strips - toxicity
- Silica gel powder - caustic, toxic
- Olive oil – stressful and not 100% effective
- Drying out cages - ineffective
- Bleach – never apply to animals
- Roccal-D, A-33 Dry – never apply to live animals
- Bathing/soaking – ineffective if done as only treatment
- Insect growth regulators – does not kill mites right away
- Tick treatments
- Cyfluthrin
- Cyfluthrin 0.01%
- Formulated for premise treatment with direct permethrin treatment of ticks on chelonians is safe and effective
- Ivermectin
- Suggested as method of tick removal for ticks hiding in nostrils, loreal/labial pits, or other body recesses
- Never give to chelonians or indigo snakes
- Cyfluthrin
-
Permethrin spray
- Preventic
- Suggested for cage, shelving, and room treatment of ticks
- Manual removal
12
Q
Describe general wound management principles in reptiles.
Once initially cleaning and closure is done, what topicals may be considered?
Describe basic bandaging of reptile wounds.
What are some types of specialized bandaging - what are the benefits of each?
A
MARMS - 130. Wound Management
General management
- Reptiles can take a long time
- Housing - optimal temperature, proper diet (assist/tube feeding if needed)
- Stabilize prior to anesthesia
- Pain management and antibiotics if indicated
- Stabilize fractures
- Control hemorrhage
- Lavage - warm electrolyte solution, sterile saline, 0.05% chlorhexidine solution, 0.1-1% povidone-iodine
- Surgical debridement to remove nonviable tissue
- Granulex V- enzymatic debridement
- Snakes with dermatitis - medicated bath (dilute chlorhexidine or povidone) for 10 to 20 min (bathe in freshwater first so it can drink)
- Closure - second intention; sutured if needed
- Nylon, polypropylene, polydioxanone, poliglecaprone 25, polyglyconate
- Everting pattern (prevent inversion to assist with shed)
- Remove in 6 weeks (some heal sooner)
- Topicals
- Rotate topicals over time to avoid resistance or if one fails
- Silver sulfadiazine cream, triple antibiotic ointment, doxycycline gel, aluminum spray, nitrofurazone, aloe vera, sugar, honey
- Healing - growth factors (Regranex), maltodextrin, chitosan, acemannan
- Skin protectant - Ilex paste (mix with antimicrobials)
Basic Bandaging
- Benefits: protection from contamination, eliminates dead spac, immobilization, support, moist environment
- Light dressings preferred
- 3 layers
- Non Adherent dressing over wound - telfa, adaptic, silver impregnated, hydrogels
- Support and reduction of mobility (often omitted with reptiles as often not necessary/useful)- cast padding, rolled gauze, splint
- Adhesive films - tegaderm, vetrap, adhesive tapes
- Depending on animal and situation, bandage changed daily to once a week
- Doesn’t work in snakes - use tie over bandage
Specialized Bandaging
- Tie-over bandage - mobile, difficult to cover
- Nonabsorbable suture loops around wound -> topicals, telfa, gauze -> umbilical tape
- Change every 1-4 days
- Vacuum-assisted closure therapy
- Shell defect
- Reduction of healing time - months; promotes contraction of wound margins, encourages granulation, increases tissue perfusion, removes exudates, reduces edema
- Chelonians - collapsed lung tissue back into original location
- Open cell foam in wound bed, covered by airtight dressing and attached to suction
- Gauze and saline or sterile water to keep it moist
- Foam should shrink beneath film
- Negative pressure: 100-175 mm Hg in chelonians for 24 hours/day
- Time off between bandage changes - aquatic turtles can swim
- 3-43 days in terrestrial chelonians; a few weeks-months in sea turtles
Supplemental therapies
- Skin grafts have been used in reptiles
- Alternative therapies in mammals - low-level cool laser therapy, electroacupuncture, hyperbaric oxygen therapy, stem cell therapy, platelet-rich plasma
- More research needed in reptiles
13
Q
What are some potential causes of bite wounds to reptiles?
What are the basic treatments to address bite wounds in reptiles?
What are some prognostic indicators in severe wounds?
A
MARMS – 142. Bite Wounds and Prey Induced Trauma
- Bites from cats/dogs, other predators and rodent/invert prey are common
- Conspecific aggression
- housing males together, competition food or basking area
- Reptiles typically solitary
- Pre kill prey (live rodent feeding illegal in some places)
- Wounds around mouth
- Injure anorectic reptiles
- Insects
- Tongue feeding
- Separate containers can be used
- Don’t leave pet reptiles unattended in yard
Treatments
- Address hemorrhage
- Flush with sterile saline
- Sedation and analgesia
- Remove necrotic tissue
- Suturing - only if fresh (and needed), not punctures
- Surgery if needed - amputation, enucleation
- Topical and systemic antibiotics: contaminated, infected or wounds >6-12 hours old: culture
- Dressings changed regularly, prevention of myiasis
- Esophageal tube if needed
Housing: newspapers, paper towels, damp towels (water turtles)
Prognosis depends on injury
- Puncture to gi tract or other organ can have grave prognosis
14
Q
What is dysecdysis?
What are some potential causes?
How do animals present?
What is teh treatment of dysecdysis?
How can it be prevented?
A
MARMS – 149. Dysecdysis
- Definition: abnormal or impaired shedding of outer layer of skin in reptiles/amphibians
- Etiology
- Nonspecific finding
- Infectious (i.e. ectoparasites, fungi)
- Low humidity
- Other noninfectious conditions that interfere with normal skin integrity
- Dehydration (disorders leading to dehydration) – reduction of fluid necessary at cleavage zone for separation of old and new epidermal layers
- Disorders resulting in hypoproteinemia – interferes with normal enzyme production for breakdown of fission layer
- Clinical presentation
- Can affect entire integument and adnexa or certain areas
- Often presents as constricting bands, esp around digits and tail in lizards
- Can lead to avascular necrosis and/or loss of distal extremities
- Retained spectacles in snakes and some geckos – accumulation of several incomplete sloughs – appear dull and wrinkled uni or bilaterally
- Important history: species normal, age, size, characteristics of past molts/skin issues, concurrent illness
- +/- increased respiratory sounds if retained around nostrils
- Diagnosis: PE +/- other diagnostics for underlying cause
- Treatment
- Do not aggressively peel – rarely emergent condition and premature removal can result in ulceration, corneal exposure for spectacles, loss of proteinaceous fluids, permanent skin/eye damage or scars
- Lightly spray animal and increase humidity for minor cases
- Short soaks in lukewarm water for larger portions (esp snakes)
- Addition of plain water
- Excessive moisture can predispose to bacterial/mycotic disease and reduce skin integrity
- Prevention
- Proper husbandry
- Don’t handle during sloughing (esp snakes and certain lizard species – particularly vulnerable to trauma and infection)
15
Q
Where are the scent glands located in snakes?
What sex are they larger in? What is their function?
What are some risk factors for scent gland adenitis in snakes?
What are the typical findings on examination?
What are the recommended treatments in mild and in more severe cases?
A
MARMS – 144. Cloacal Scent Gland Adenitis
- Paired cloacal scent glands present in all species of snakes.
- Unique to ophidians.
- Males and females (larger).
- Specialized exocrine glands that produce thick semi-liqui material containing pheromones and semiochemicals to mark objects and organisms.
- Clinical Significance and Known Etiological Causes:
- Scent gland adenitis reported in snakes.
- More common in older, female, colubrids and active breeders.
- Impacted material becomes inspissated, gland secondarily infected, may rupture.
- Mineralization and neoplasia possible.
- Usually unilateral.
- Environmental factors – humidity, substrate (paper or carpet vs natural), poor sanitation, presence or absence of conspecifics.
- Several cases of neoplasia assoc with scent glands.
- Fibrosarcoma reported in a colubrid snake.
- Scent gland adenitis reported in snakes.
- Clinical Presentation and Diagnostic Confirmation:
- Older, actively breeding females.
- PE often diagnostic.
- Unilateral or bilateral swellings caudal and lateral or craniolateral to cloaca.
- Rupture of gland may occur.
- FNA and cytology can confirm gland involvement or neoplasia.
- Rads not very useful other than confirming mineralization.
- US can differentiate between neoplastic tissue and impaction.
- Biopsy for histo and microbiology at surgery often needed for definitive dx.
- Preferred Tx:
- Mild impaction – massage gland after warm water soak to move material toward opening for release.
- Large snakes – cannulation of duct opening under sedation or anesthesia can be attempted.
- Usually surgical.
- Incision between lateral scale rows over the enlarged gland.
- Opened, material removed, biopsies of gland collected for histo anc culture.
- Lavage and pass catheter to ensure patency.
- Can also marsupialize or cloase to allow flushing and treatment when cannulated.
- Systemic abx or topicals may be warranted.
- Along with local flushing with antiseptics.
- Surgical removal of entire gland often curative choice if severe, reoccurring, bilateral, or neoplasia.
- Prognosis and Prevention:
- Good with complete sx removal of gland, address underlying conditions.
- Type of neoplasia determines prognosis.
16
Q
Describe the anatomy of the shell.
How does the bone of the shell form embryologically?
How do the scutes form?
What is the naming convention of the bony plates and scutes?
What is a fontanel?
What are some differences in the shell between males and females?
A
Anatomy
- Carapace and plastron joined by bridge
- Formation of carapace
- Hard-shell chelonians - exo- and endoskeletal ossification
- Bone morphogenic proteins (BMPs) secreted by ribs and induce metaplastic ossification of surrounding intramembranous dermal cells
- Takes place after hatching
- Soft-shell chelonians - growth of costal bony plates is concentrated to area close to vertebrae and seems to be solely from extensions of periosteum of ribs
- Hard-shell chelonians - exo- and endoskeletal ossification
- Formation of plastron
- Hard-shell chelonians - composed of nine bony plates, develop by dermal ossification
- Formation of scutes
- Scutes overlying dermal bone originate from local epithelial thickenings called placodes
- Location of scute seams does not show a one-to-one conformance to seams of their bony counterparts
- Formation of carapace
- Shell - formed by 58 bony plates (49 carapacial and 9 plastral) of dermal origin and covered by epidermal keratin scutes
- Scutes - epidermal layer of hard-shell turtles consists of 38 carapacial and 16 plastral scutes
- Kinesis of the shell - development of flexibility of shell by means of skeletal hinges
- Plastral, carapacial, or pankinesis
- Fontanels - membranous gaps between growing bony segments of the shell
- Large in some hatchlings
Physiology
- Counting rings around scutes inaccurate for aging
- Sexual dimorphism
- Females – larger, more vaulted carapace, increased kinesis of caudal plastron in some species, fontanels may be retained longer
- Males – more concave plastron, epiplastron (some species)
- Shell acts as a buffer reserve by uptaking lactic acid in exchange with carbonates and bicarbonates when submerged for long periods in some freshwater turtles
17
Q
Describe some of the common shell diseases of turtles.
What causes ankylosis? How can it be addressed?
What are some of the causes of pyramiding? How can it be addressed?
What are some infectious differentials for a young tortoise with a soft shell? What other signs may also be present? What diagnostics shoudl be perfromed and what treatments are available?
A
Diseases
- Scute anomalies
- Highly variable scutation in olive loggerhead sea turtles
- Risk factors for anomalies - high temperatures, desiccation, and pollution
- Most common anomaly - supernumerary scutes
- Ankylosis – distorted growth
- Closure of bony sutures impeding further growth
- Irregular growth of bony plates is common in chelonians
- Scoliosis, kyphosis, and lordosis – uncommon in chelonians
- Possible causes – genetic, trauma, dietary, ambient
- In the early stages of deformation, dental expansion screws can be glued between caudal carapace and plastron on either side of cloaca to allow widening of caudal shell opening
- Consider ovariectomy to prevent dystocia if concern for impact on oviposition
- Pyramiding - humped appearance of the carapace
- Trabecular bone thickening between the inner and outer bone cortices of the shell
- Causes - high dietary protein, inappropriate dietary calcium:phosphorus ratios, improper UV lighting, elevated temperature, low dietary fiber, overfeeding, inadequate humidity
- Tx - correct low humidity, high nocturnal temperature, and diet
- Softening of the Shell in Juvenile Herbivorous Tortoises
- Described in juvenile Testudo hermanni, T. graeca, T. marginata, Geochelone elegans, and Geochelone pardalis
- Pathology associated with picornavirus infections
- Cryptosporidiosis, Balantidium, and Hexamita spp infestations also associated with shell softening
- Picornavirus infections and Hexamita infection often seen in conjunction with nephropathy leading to renal secondary hyperparathyroidism and osteodystrophy
- Ddx - MBD
- Signs - hatchlings at 6-8 wks old present with rhinitis, conjunctivitis, and anorexia, translucency of grayish plastron, gallbladder may be visible as dark spot on right, progressive softening of entire shell
- Dx – recommend pharyngeal swabs (for picornavirus PCR), fecal evaluations (for Cryptosporidium and Balantidium), and urinalysis (for Hexamita)
- Tx - Supportive care (fluid therapy, nutritional support), catheterization and voiding the bladder if distended and causing resp compromise
- Prognosis – guarded
19
Q
What is septicemic cutaneous ulcerative disease?
What are the typical clinical signs?
What are some predisposing factors for developing this disease?
How is it treated?
What is the causes of white spot disease (hyalohyphomycosis) in softshelled turtles?
What are the typical lesions?
How are they treated?
A
- Bacterial Shell Dermatitis/Osteomyelitis (Including Septicemic Cutaneous Ulcerative Disease)
- SCUD - considered a syndrome associated with various bacteria, rather than single obligate pathogen
- Signs - dermatitis and osteomyelitis
- Definitive diagnosis requires shell biopsy for microbiology (bacterial and fungal cultures) and histopathology
- Biopsy sites closed with methylmethacrylate containing bone cement
- Total shell disease score (TSDS) system
- Tx - surgical debridement, dry docking aquatic species, bandages, topical and systemic antimicrobials based on culture and sensitivity testing
- Tx of shell ulcerations using photopolymerizable nanohybrid composite appears to prevent relapses and allows faster return of aquatic turtles to environment
- Metronidazole or ceftazidime should be considered where anaerobes suspected or confirmed
- Use of vacuum-assisted wound closure with silver impregnated bandaging materials promotes faster healing
- High humidity, low temperatures, poor nutrition, under-floor heaters, traumatized skin or shell tend to be predisposing factors for development of shell infections (anecdotal)
- Mycotic Shell Dermatitis/Osteomyelitis (Including White Spot Disease in Softshelled Turtles)
- White or pale discoloration of shell - “white-spot disease” in softshelled turtles
-
Purpureocillium lilacinum (Paecilomyces lilacinus) - etiological agent of hyalohyphomycosis
- Characterized by white to gray spots on the carapace, plastron, and skin, diagnosed in Chinese softshelled turtles and Fly River turtles
- Ddx - White papular carapacial lesions also seen in conjunction with generalized Mycobacterium kansasii infection
- Lesions - white to gray cottonlike spots or discolorations on the carapace, plastron, skin
- Dx - biopsy for fungal culture and histopathology
- Secondary bacterial infections common - bacterial culture also recommended
- Tx
- Hyalohyphomycosis - successfully treated in Fly River turtles with 0.038% malachite green and 4.26% formaldehyde dips and systemic itraconazole
22
Q
What are some of the causes of shell abnormalities in turtles?
A
MARMS – 165. Shell Abnormalities
- Common issues – trauma, infection, neoplasia (SCC)
- Infections commonly bacterial or fungal
- Bacteria - Citrobacter freundii, Beneckea chitinovora, Aeromonas hydrophila, Mycobacterium kansasii, Clostridium sp.
- Fungi - Mucor spp., Purpureocillium (Paecilomyces) lilacinus, Aphanomyces sinensis, Fusarium semitectum, Exophiala oligosperma
- Viral - less common
- Herpesviruses – fibropapillomatosis (primary lesions)
- Picornaviruses - secondary osteodystrophy
- Nutritional or renal secondary hyperparathyroidism - osteodystrophic softening of shell
- Infections commonly bacterial or fungal
- Imaging
- CT preferred but 3 view rads helpful
- Shell biopsy can be performed to diagnose lesions
- Tx
- Treat according to underlying etiology
- Vacuum-assisted wound closure with silver impregnated bandaging materials is indicated for extensive lesions
24
Q
Describe the surgical repair of shell fractures in turtles.
What anesthetic considerations should be made for these patients?
How long does it take bone to heal?
Is the fracture and not-displaced, is surgery necessary?
When are bone plates considereed?
When is epoxy contraindicated?
Describe the use of the screw and wire fixation method.
How does the management change if the wound was due to a predator bite?
A
Surgical Management
- Anesthesia
- Supplemental heat consistent with POTZ
- Most common used from authors:
- Analgesia: Morphine, tramadol, and meloxicam
- Anestheics: Ketamine, Dexmedetomidine, propofol, alphaxalone, and inhalants
- Fracture Repair & Fixation
- Bone healing 1-6 months or longer
- Non-displaced and stable- external bandaging
- Bone plates for larger chelonians, sea turtles, and giant tortoises
- Perfect apposition is not mandatory or often possible
- Residual cracks and voids will be undergrown by granulation tissue and ossifying coelomic membrane.
- Adhesives & Epoxy
- Epoxy and fiberglass is the preferred method
- Contraindicated with infected shell injuries
- Epoxy and fiberglass is the preferred method
- Fixation with Hardware
- Stainless steel screws and NOT galvanized b/c released of zinc systemically and more likely to rust
- No financial restraints- surgical steel-grade implants are favored.
- Sterilize fixation devices before use
- Screw and Wire Fixation
- Maybe the BEST stabilization in most cases
- Using drill- stay away at least 0.5cm from edge of fractures, not too much pressure on drill, place tape at bit at 0.20cm (⅛ to ¼ inch) or use drill sleleve
- Avoid full penetration
- Watch out for heat (cause necrosis), so drip sterile saline on bit
- Some instances- aquatics, epoxy putty can bridge screws
- RediHeal and bone cement with antibiotics along fracture line (changed once weekly)
- Cable Tie & Hook Fixation
- Quick-drying equine hoof acrylic- to attach bra hooks and cable tie bases
- Plastic saddle clamps
- Epoxy and Metal Fixation
- Monitoring and Healing Time
- 4-8 weeks bone healing time, but can be prolonged
- Do not allow hibernate before healing b/c of downregulation of immune response
Management of Dog or Predator Bites
- Even if visera exposed- still reasonable prognosis if infection is controlled
- All superficial shell wounds will develop yellowish granulation tissue (do not mistake for purulent discharge)
