Post Hibernation Anorexia

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1 Post Hibernation Anorexia Author: Mark N Rowland BVSc CertZooMed MRCVS Anorexia is a common presentation for tortoises in the post hibernation period. There are many potential causes of this potentially devastating condition. This communication is intended to assist veterinary surgeons in the work up, diagnosis and treatment of post hibernation anorexia (pha) in chelonia. Signalment The potential issues that may lead to pha begin in the previous year. Firstly it is important to establish that the tortoise presented is a species that hibernates. Attempting to hibernate a non hibernating species is potentially fatal to the tortoise. Species commonly presented that do not hibernate include Leopard, Red foot, Yellow foot, Indian Star and Sulcata (African spurred) tortoises. This is not an exhaustive list but many keepers of the more exotic tortoises will know not to hibernate a species that does not do so in the wild. The most common hibernating species include the Spur thigh, Hermanns, Marginated and Horsefields tortoises. It is very important to ensure that there were no problems with the tortoise prior to its hibernation. If there were any disease process occurring then it may be exacerbated by the hibernation, putting huge stress on the animal. If the animal was weighed prior to hibernation, this weight should be noted and compared to a post hibernation weight. A healthy tortoise will loose about 1% of its bodyweight per month during hibernation. Pathophysiology There are several factors which contribute to the disease processes identified in pha. à Improper preparation for hibernation. The wind down period is a period in the autumn during which the tortoise prepares itself for hibernation. Characteristically, tortoises will become more lethargic and abstain from food for a period of 4-6 weeks (shorter for young tortoises). This allows them to empty their gastro- intestinal tract. It is important during this period to ensure that the tortoise is fit to hibernate and is bathed regularly to build up fluid stores that it will rely on during hibernation. If the wind down is not carried out normally and the tortoise is not physiologically ready to hibernate, post hibernation problems are likely.

2 à Duration of hibernation. If left to their own devices, tortoises would hibernate for much longer in the UK than they would in the wild. This is because the cues to wake up (notably increasing ambient temperature) are not present in the British climate. This has tremendous implications for tortoise health. During the hibernation period tortoises are still producing nitrogenous waste products albeit to a lesser extent. They are using their own body water (much of it stored in the bladder) to dilute these waste products. A tortoise hibernating for 3-4 months will have enough body water to successfully dilute waste for this period. In the UK, tortoises frequently present having hibernated for 5-6 months. As a result they have become severely dehydrated and are hyperuricaemic. In severe cases, uric acid can come out of solution as its solubility is relatively low. This will result in visceral gout and organ damage. à Hibernating conditions. It is very important to ensure that the tortoise has hibernated under the correct conditions. The tortoise should be safe from predator attack and have access to fresh air. Hibernating at too warm a temperature will increase metabolic rate and therefore catabolism. If the tortoise is too cold, frost damage will cause damage to a tortoise s sight. The ideal hibernating temperature is 4-6 degrees Celsius. à Immune status. Clinically healthy tortoises in the UK often have subclinical leucopaenia because of lower temperatures and ultraviolet light levels. During hibernation white cell production is suppressed. The life span of chelonian white blood cells is on average 3-4 weeks. This means that at the end of the hibernation period tortoises are immunocompramised. It can take several weeks for white cell production to increase dramatically. The net result is that in the immediate post hibernation period, tortoises are susceptible to a large number of diseases caused by opportunistic pathogens. These animals will present with a wide range of clinical syndromes including stomatitis, pneumonia, aural abscessation, conjunctivitis, rhinitis, skin/shell infections and septicaemia. Diagnosis The diagnosis of pha is relatively straightforward. These tortoises present soon after they have woken and may be totally collapsed or bright but simply anorexic for more than a week after waking. Subtle jaw movements are frequently noted on clinical examination of dehydrated pha cases. An investigation into the underlying cause is always warranted as well as the treatment of any obvious pathology uncovered during a physical examination. If the tortoise has urinated the urine should be examined for any changes in colouration. Green stained urates can be indicative of liver disease in chelonia. A direct wet prep of urine may reveal the presence of large number of motile protozoa. Pha cases are often desperately sick and require early and aggressive therapy. Initial treatment and investigation Many cases of pha require hospitalisation for investigation of the underlying cause as well as the initiation of aggressive supportive care. It is of vital importance that these reptiles

3 are hospitalised within their activity temperature range (ATR). Their physiology is adapted to operate at higher than UK room temperature. In practical terms, this means that they should be provided with a background temperature of 25-30C, dropping to roughly 16C at night. Ultraviolet light should be provided for 14 hours daily. This will help to stimulate the tortoise s immune system as well as increase its general well being. These animals require barrier nursing to prevent cross infection of disease. This is especially important as hospitalised pha cases will be immunocompramised as stated previously. Blood should be drawn from the right jugular vein and submitted for biochemistry and haematology. It is important to send the blood to a laboratory that is experienced with reptilian samples. Alternative sites include the dorsal coccygeal vein and the subcarapacial venous sinus. However there is a more significant chance of lymph dilution with these sites which will affect any results obtained. Blood may be collected into a heparin tube for both biochemistry and haematology. In fact, reptilian blood cells are better preserved in heparin than in EDTA. Up to 1% of bodyweight may be taken. Most labs however are able to provide a basic reptile profile with as little as ml of whole blood. Many reptilian profiles do not include urea measurement. Urea levels are an important indicator of dehydration in post hibernation cases and should be added to the profile if possible. Fluid therapy Fluid therapy is profoundly important in cases of post hibernation anorexia. Maintenance fluid requirements for tortoises are 10-30mls/Kg/day. Many pha cases are suffering from dehydration and so will require fluid replacement. Fluid deficit replacement should take place over 2-4 days to avoid volume overload. The upper limit for fluid replacement is roughly 40ml/kg/day. There are several routes available for fluid replacement. à Intravenous/intraosseous: These routes are available for continuous rate infusion and are suited for severely dehydrated reptiles (in which other routes may be less effective). The jugular vein may be accessed for intravenous therapy. For intraosseous therapy the author prefers the gular scutes at the cranial plastron. à Epicoelomic: This route is useful for bolus administration and has the advantage of being remote from the bladder so iatrogenic bladder puncture is less likely. Injection is through the cranial inlet of the shell, laterodorsal to the head and neck, just dorsal to the plastron. Up to 20mls may be delivered via this route. à Coelomic: The site for coelomic fluid injection is the prefemoral fossa. Care should be exercised to avoid accidental puncture of the bladder, the contents of which are non sterile. Up to 30mls of fluids may be administered. à Oral: Stomach volume is estimated at 5% of body weight. This is the normal physiological route. Fluids may be given by gavage tube or a pharangostomy tube may be fitted under light anaesthesia. The author prefers a bolus of 5mg/kg alfaxalone (Alfaxan; Vetoquinol) given intravenously to allow sufficient sedation for this procedure even in debilitated tortoises. à Bathing: It is postulated that cloacal drinking occurs in terrestrial chelonia. Daily bathing in warm water will stimulate the tortoise to void urine and may help in rehydrating

4 mild cases of pha. Products such as Reptoboost (Vetark) are available to add to the bath. The products contain energy precursors, probiotics and electrolytes. Normal saline is acceptable for initial rehydration. Oral rehydration formulas like Critical Care Formula (Vetark) are also useful for this period. Nutritional Support Nutritional therapy may commence once the patient is stabilised. It is important not to introduce nutritional therapy too soon. If this occurs, the sudden release of insulin may result in a profound hypokalaemia and hypophosphataemia. This phenomenon is known as refeeding syndrome and can have life threatening consequences in an already debilitated patient. The author prefers Critical Care for Herbivores (Oxbow) for initial and continued nutritional support in these cases. Specific Conditions 1) Hyperuricaemia/Gout: As stated, rising uric acid levels may result in precipitation of urates. This will lead to visceral or articular gout. The temperomandibular joint seems to be commonly affected. Treatment with allopurinol (20mg/kg/day orally) will decrease uric acid production and so reduce levels. Uric acid crystals will damage any organ they are deposited in and therefore lead to dysfunction of that organ. 2) Rodent injuries: These are common where tortoises to not have adequate protection whilst hibernating. They may be severe, possibly requiring limb amputation. Adequate stabilisation, analgesia, antibiosis and wound management are required. 3) Stomatitis (Mouth Rot): Bacterial infections in the buccal cavity are common in cases of pha. Often there are large yellow necrotic plaques of tissue on the tongue and oral mucosa. Treatment includes culture and sensitivity of the swabbed lesions, Herpes virus PCR of oral swabs and antibiosis and analgesics as indicated along with appropriate supportive care. 4) Runny nose syndrome: Normal chelonian respiration should not include evidence of nasal discharge or bubbles at the nares. If this is present, appropriate antibiosis based on culture alongside nebulisation are required. Herpes virus testing is also recommended. Many ocular antibiotic drops may be instilled into the nasal cavity (e.g. chloramphenicol drops, ciprofloxacin drops). 5) Pneumonia: this condition is usually diagnosed by cranio- caudal and lateral radiographs. The lungs are dorsal to the coelomic viscera and can be sky lined with these views. Nebulisation, fluid therapy and antibiosis based on culture of lung secretions are required for treatment which should be aggressive and may be protracted. 6) Aural abscessation: Abscesses of the ear arise as extensions of stomatitis where the infection tracks up the eustachian tube. Large swellings over the tympanic scale may be seen uni or bilaterally. These abscesses require surgical debridement. A ventral window is created in the tympanic scale and the pus is removed. The pus is usually

5 very thick and leaves a cavity after it has been removed. The wound is left open for gentle irrigation and heals by secondary intention. 7) Blindness: This is caused by frost damage if the tortoise is hibernated at too cool temperatures. Associated ocular lesions include hyphema, vitreal haze, lenticular opacities and retinal damage. Improvement over time may be noted. Circling may also be a clinical feature. 8) Parasitism: Adult roundworms will overwinter inside the tortoise during the hibernation period. If on waking the tortoise is debilitated through concurrent disease, intestinal parasitism may play a role in worsening the situation. Whole worms may be passed or eggs and larvae may be visible on examination of a direct faecal wet mount. Urine should also be examined ad protozoal parasites e.g. Hexamiter spp may cause renal disease in chelonia. 9) Septicaemia: many bacterial diseases of chelonia can lead to a generalised infection (septicaemia). This condition is life threatening and requires aggressive therapy. Blood culture may be helpful in these cases. If left untreated, haematogenous spread of infection will occur leading to osteomyelitis and valvular endocarditis. A septicaemic red flush is often noted on the plastron in these cases. Summary Most cases of post hibernation anorexia in tortoises can be managed with appropriate supportive care and fluid replacement. However it is important to identify those cases which may require more invasive or long term care as soon as possible in order to exact a successful outcome. Client education is also vital to ensure that any husbandry related causes are identified and corrected. FOR FURTHER INFORMATION INCLUDING VIDEOS OF TORTOISE VENEPUNCTURE, FLUID THERAPY AND SELECTED SURGICAL PROCEDURES, PLEASE VISIT cpd.co.uk Formulary Antibacterial drugs: Ceftidazidime Enrofloxacin Lincomycin Marbofloxacin Metronidazole Trimethoprim/sulpha 20mg/kg im q 72hrs 5-10mg/kg im q 48hrs 5mg/Kg im q 24hrs 10mg/kg im q 24hrs 20-40mg/kg po q 48hrs 20mg/kg im q 24hrs

6 Antiparasitic drugs Fenbendazole Metronidazole Praziquantel Pyrantel Nematodes: 25mg/kg po q 7d for up to 4 treatments Flagellates 150mg/kg po repeat in 14 days (Nb metronidazole is an appetite stimulant in tortoises) Cestodes: 8mg/kg im repeat in 14 days Nematodes: 5mg/kg po repeat in 7 days Topical preparations: Silver sulfadiazine: Topical antibacterial/antifungal gel for deramtitis F10 (Benzalkonium chloride/polyhexanide): Topical gel for wounds/dermatitis Anaesthetics/analgesics Alfaxalone 5-10mg/kg iv (authors preferred agent) Buprenorphine 0.1mg/kg im q 12h Butorphanol 1-2mg/kg im q 6-8hr Isoflurane 3-5% induction, 1% maintenance Meloxicam 0.3mg/kg q24hr Propofol 10mg/kg iv Sevoflurane 5-8% induction, 2-3% maintenance References Highfield, Lancaster Safer Hibernation and your Tortoise Kirchgnesser,Mitchell in Manual of Exotic Pet Practice Saunders,Elesevier (2009) pp Calvert I in BSAVA Manual of Reptiles 2 nd edition, BSAVA (2004) pp Carpenter, Exotic Animal Formulary 3 rd edition, Elesevier Saunders (2005)

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