Heather A. Bjornebo, DVM, DABVP (Reptile and Amphibian Practice), CertAqV
There are few true reptile emergencies which include trauma, toxicity, or envenomation. Reptiles often present critical on emergency with previously unaddressed, chronic illness. Seizures, hemorrhage, organ prolapse, severe trauma, dyspnea, and loss of responsiveness are all clinical presentations that warrant emergency evaluation in reptile patients. Triage should occur on presentation, and a thorough history should be obtained along with a thorough physical examination, and various diagnostic modalities should be utilized to further assess the critical reptile patient. Providing supportive care along with appropriate treatment is paramount to patient recovery.1,2
Introduction
It is often said there are few true reptile emergencies. True, acute emergencies often occur in cases of trauma, toxicity, or envenomation. However, it is common for reptiles to present on emergency after a protracted course of illness that either has gone unaddressed or unnoticed by the owner. Patient status may be quite critical in these cases. Seizures, hemorrhage, organ prolapse, severe trauma, dyspnea, and loss of responsiveness are all clinical presentations that warrant emergency evaluation in reptile patients.1,2
Assessment, Triage, and Diagnostics
A thorough history should be obtained for any reptile presenting for physical examination and should include a review of where the animal was obtained, previous medical treatment, and current husbandry. Husbandry should be compared to that species’ natural environment, diet, and behaviors found in the wild, as deficits in meeting the patient’s husbandry needs often contribute to the onset of disease. Correction of any deficiencies will be necessary for resolution of the disease.2 As with mammalian patients, information such as diet, abnormal behaviors, or weight changes should be recorded.1,2
It is also important to determine the temperature ranges provided in the reptile’s environmental home enclosure. Reptiles are poikilothermic and should be kept within their preferred optimal temperature zone (POTZ) while hospitalized, to allow for best possible metabolic and immune function. Patients whose body temperature is low on arrival to the hospital should be warmed to within their POTZ slowly over 4–5 hours. Acceptable methods include warming blankets, heated air blankets, heat lamps, or incubators. Many physiologic parameters are best evaluated after the patient has reached optimal temperature.1,2
Mucous membrane color and capillary refill time are not accurate assessments of cardiovascular function in reptile patients. Indirect blood pressure measures are often inconsistent and inaccurate, and direct measurement is often too invasive and not practical for clinical use. The best means to assess the cardiovascular system is by determining heart rate. However, cardiac size and anatomy in reptiles often inhibit auscultation with a standard stethoscope. Ultrasonic Doppler flow detectors directed over the heart or major arteries are necessary to evaluate the heart in most reptile patients. Larger lizards and crocodilians may require ultrasonography to assess cardiac function. It should be noted that presence of a heartbeat does not necessarily indicate a reptile patient is alive—their hearts may beat for hours after brain function ceases. It is important to record baseline heart rates once the patient is within their POTZ, because heart rate is highly dependent on body temperature in reptiles.1,2
Normal respirations for reptiles can be slow and intermittent. Observe the patient prior to handling, as stress can greatly influence respiratory rate and character. Dyspnea in reptiles can be recognized often by exaggerated respiratory movements. A dyspneic patient may open-mouth gasp with each breath or display extension of the head, neck, and forelimbs. In the event of respiratory arrest, immediately evaluate heart function with a Doppler flow meter and proceed with cardiopulmonary cerebral resuscitation (CPCR) if necessary.1,2
It is important to assess mentation and neurologic status; sick reptiles often present with lethargic to dull mentation. Righting reflexes can be determined by placing lizards and snakes into dorsal recumbency. In patients willing to ambulate, gait should be observed. Evaluating reptile patients for pain can be challenging for the practitioner, as behavioral signs of pain tend to be far subtler than in mammals or birds. As a general rule, any condition that would be considered painful in higher vertebrates should be considered painful in reptiles, and analgesia should be provided appropriately.1
Hydration status can be subjectively evaluated on examination. Dehydration in reptiles can manifest as a decrease in skin elasticity, decreased skin and eyelid turgor, eyes appearing sunken to the orbits, tacky mucous membranes, doughy coelom on palpation, and thick, stringy saliva. Blood collection provides a more objective evaluation of hydration status. Dehydration may manifest with increases in packed cell volume, total protein, uric acid, blood urea nitrogen (chelonians and crocodilians), sodium, and chloride. Urine specific gravity is of little value in the dehydrated reptile patient, as these species lack the ability to concentrate urine above plasma osmolality.1
As with mammalian patients, the importance of blood collection and evaluation to the reptile emergency patient goes beyond evaluation of hydration status. Normal blood pH in reptiles ranges between 7.5 and 7.7, and total CO2 ranges between 20 and 30 mmol/L. These can be used to assess for metabolic acidosis, which may indicate renal impairment, hypovolemia, or diarrhea. However, as with many physiologic processes in these species, the acid/base system in reptiles is highly dependent on environmental temperature. Temperatures inversely impact blood pH—lower temperatures cause a transient alkalosis—so patient warming is again vital.1
Additional blood chemistry parameters that may assist in assessment of the patient include enzyme assays, glucose, calcium, and phosphorus levels. Unlike many mammal patients, enzyme activities have not been found to be organ specific. Many analytes are found in various tissues throughout the body. Interpretation of abnormal parameters requires careful deduction by the practitioner.1,3
Reptiles generally have lower blood glucose levels than those of mammals and birds. Hypoglycemia associated with specific disease processes is rarely documented. Hyperglycemia can be associated with stress, postprandial status after starvation, emergence from hibernation, breeding season (temperate reptiles), cryoprotection, forced submergence in turtles, vomiting (hypochloremic metabolic acidosis), epinephrine release, pancreatic disease, liver disease (hepatic lipidosis), renal disease, neoplasia (liver, pancreas, GI, and undifferentiated tissues), and granulomatous disease. Severe hyperglycemia (1000+ mg/dl) is associated with gastric neuroendocrine carcinomas in bearded dragons (Pogona vitticeps).1,3
Calcium and phosphorus blood levels in reptiles can be indicative of either nutritional problems or significant renal impairment. Mild hypercalcemia is also seen in reproductively active females, with severe hypercalcemia commonly observed in females with reproductive pathology.1,3
Hematology can be very beneficial to evaluating the emergency reptile patient. For the most part, indications for and the basic principles of hematology in reptiles are similar to those for mammalian patients. However, the presence of nucleated red blood cells prevents use of automated analyzers and requires manual complete blood counts. Practitioners wishing to perform this diagnostic in-house should familiarize themselves with the reptile blood cell morphology. Diagnosis of anemia should be made with caution, as lymph vessels run in tandem with veins, and contamination during sample collection causes lymphodilution. True anemias are often nonregenerative secondary to chronic illness unless resulting from acute blood loss. Polycythemia is rare and most often indicates dehydration. Leukocytosis in reptiles indicates an inflammatory process. However, absence of a reactive leukogram does not indicate lack of infection. It is common for leukocyte counts to return to normal in reptiles suffering from chronic infections. In many cases, clinical interpretation will rely on evaluation of cell ratios within the differential itself instead of overall leukocyte numbers alone.1
Diagnostic imaging can be a valuable tool in the evaluation of the emergency reptile patient. Just as with mammals, orthogonal radiographic views are recommended. Lateral radiographs should be taken with a horizontal beam if possible. Ultrasound can be especially useful in evaluation of effusions.1
Therapeutics
With all veterinary patients, good supportive care is key to any therapeutic plan. For poikilotherms, environmental optimization is paramount. As discussed above, returning the patient to the appropriate POTZ is vital for their recovery. Although reptiles do not have an endothermic fever response like mammals, they are known to increase their body temperature behaviorally during infections by basking at the higher end of their POTZ.1
Fluid therapy is indicated for patients that are dehydrated or debilitated. It is important to consider that reptiles carry a higher portion of their body fluid intracellularly versus extracellularly, with plasma only accounting for 3.3–7% of total body weight.1 Reptile osmolality is similar to mammals, and similar fluid types can be used.1,2 Maintenance fluid requirements in reptiles range from 10–30 ml/kg/d. Fluids should be warmed prior to administration.2
For reptiles that are only mildly dehydrated (<5%), fluids are typically provided through the enteral route. Enteral fluid administration may be accomplished passively by soaking the patient in shallow, warm water for 15–30 minutes or actively by gavaging fluid directly into the stomach. No more than 2–3% of body weight should be given in a single enteral dose, as larger volumes may result in regurgitation.1
Parenteral fluids are recommended for patients with more severe dehydration (>5%). Options include subcutaneous, epicoelomic, intracoelomic, intravenous, and intraosseous routes. It is recommended to limit the use of the subcutaneous route to patients <6% dehydrated, as the subcutaneous space is relatively small and poorly vascularized in reptiles. The epicoelomic route is ideal for fluid administration of all but the most debilitated chelonian patients; 1–2% of body weight can easily be administered. The epicoelomic route is ideal for hospitalized chelonians, as there is some evidence that the epicoelomic space may be connected to the pericardium and other fluid storage sites, facilitating rapid absorption. That said, the intracoelomic space is lined with a highly absorptive membrane and serosal surfaces and should be considered as an option in saurians. However, fluid administration volume is limited, as excess intracoelomic fluid can result in lung compression. As with higher vertebrates, intravenous fluid administration is the most effective method of fluid administration, but venous access can be challenging due to patient size and thick skin requiring surgical cutdown for access. In severely debilitated patients—especially when intravenous access is not possible—the intraosseous route should be considered for fluid administration. Use shorter needles and confirm placement radiographically. Large fluid boluses can be difficult to administer through intraosseous catheters due to high back pressure.1
Increased temperatures also increase the caloric needs of the patient, so it is vital to provide adequate nutritional support. Patients that remain appetent should be offered a diet appropriate for the species. Many debilitated reptiles suffer from some degree of anorexia, maldigestion, and malabsorption—necessitating assist-feeding by syringe. For patients that cannot or will not swallow, a gavage needle or red rubber catheter can be used to directly introduce food into the stomach. Care should be taken to prevent damage to the esophagus or stomach. Some patients, such as medium to large chelonians, will not tolerate restraint for assist-feeding; an indwelling feeding tube should be considered. Local or general anesthesia is required for placement. Placing a pharyngostomy or esophagostomy tube in reptiles is relatively straightforward and extremely similar to placement in mammalian patients. As with mammals, take care to ensure the tube is appropriately placed within the esophagus. Either directly visualize the tube or pull it out through the mouth before redirecting it down the esophagus. The tube should extend into the stomach, and its position should be confirmed radiographically. It is important that the tube is not placed too deeply; excessive depth can cause pressure necrosis of the stomach wall. The tube should be secured to the skin, as with mammal patients, and then further secured in a way that the animal cannot easily dislodge it. It will need to remain in place until the patient’s appetite and weight have returned to normal. Once removed, the stoma can be allowed to heal via second intention.1,4
High-quality commercial assist-feeding diets are available and have been specifically formulated for herbivores, carnivores, omnivores, and piscivores. Selection should depend on the species’ dietary requirements. These diets are stored as a powder and reconstituted with water prior to administration. These commercial diets are highly digestible, absorbable, and nutritionally dense. Care should be taken to make sure patients are adequately hydrated when feeding reconstituted powdered diets; dehydration of the product within the gastrointestinal tract can lead to obstruction. This complication can be easily reversed once adequate hydration is restored.1,4
Determining feeding volume and frequency can be challenging for reptile patients. Caloric requirements are not well understood in reptiles, and volume tends to be the limiting factor when assist-feeding. Because of this, feeding by volume versus by caloric need tends to be more practical for clinicians.1,4 As a general guideline, feed approximately 3% of body weight and adjust this volume based on the individual patient’s needs.9 However, chronically anorexic reptiles should be slowly returned to full feeding volumes. After initially focusing on rehydration, limit intake to only 10–15% of the daily calculated requirements and closely monitor plasma levels of phosphorus, potassium, and magnesium to prevent refeeding syndrome.1
Appropriate antibiotic therapy should be initiated when indicated. Culture and sensitivity testing should inform antibiotic selection when possible. In the interim, initial antibiotic therapy should be selected since most isolates in reptile patients are gram negative. A practitioner should always take the patient’s health status into account and avoid medications that may be contraindicated based on any concurrent pathology. In addition, the route of administration must also be considered when selecting antimicrobials, as both ease of administration and skill level of the administrator affect client compliance. Good hydration should be maintained throughout antibiotic therapy. Common first-choice antibiotics include amikacin, ceftazidime, enrofloxacin, and trimethoprim-sulfas.1,5
Cardiopulmonary-Cerebral Resuscitation (CPCR)
The basic principles of CPCR apply to reptile patients despite the lack of established guidelines for these species. The airway should be secured with endotracheal intubation so oxygen therapy can be provided with positive-pressure ventilation at 6–8 breaths per minute. Cardiac compressions should be initiated in absence of a heartbeat. Administration of emergency medications (epinephrine [1:1000] 0.5 ml/kg IV, IO, or IC and atropine 0.01–0.04 mg/kg IV, IO, or IM; 0.2 mg/kg SC or IM) and IV or IO fluids to address hypovolemia should follow.1
Common Reptile Emergency Presentations
Traumatic
Traumatic injuries are probably the most common reason for emergency presentation in reptiles and include burns, animal bites, blunt force trauma, and fractures.2,6,7 Ocular trauma is also quite common in reptiles and may involve either the globe itself or the spectacle.2 As with mammals, prompt treatment is encouraged, as time can result in decreased tissue viability and increased morbidity.2,6,7 Thermal burns are often associated with animals coming into direct contact with enclosure heating devices such as heat rocks or heat lamps.1,2,6,7 Not all burns are immediately obvious, as reptiles do not develop the flush seen with mammals.7 Prompt treatment and good wound management are important. Antibiotic therapy is warranted as secondary bacterial infections are common. Analgesia should be provided.1,2,6,7
Animal bites are extremely common. Rodent bites are often seen in snakes fed live prey items and can range from a single bite to extensive trauma if the rodent was left unattended with the snake for a prolonged period of time. Just as with burns, treatment of these injuries proceeds with wound management, antibiotics, and analgesia.2,6,7
Dog bites are extremely common in chelonians, and extensive shell trauma can occur. Other causes of shell trauma include lawn equipment and vehicular collisions. Grading the injury can help in development of a treatment plan and providing the owner with a prognosis. In general, the larger and deeper the injury, the graver the prognosis. Shell trauma should be treated with open wound management instead of closure with a patch, if at all possible. While patching a shell may at first seem ideal, patches preclude adequate monitoring of the wound. If a patch is to be employed, apply it only after thorough disinfection of the wound. For contaminated wounds, disinfection may mean daily lavage with sterile saline for 3–4 days. Patches should be removed after 1 month and then every 1–3 months until the wound heals, to allow for monitoring.2,6,8
Fractures are not immediately life-threatening and should not be considered a true emergency.7 Fractures in reptiles fall into two types: traumatic versus pathologic. Pathologic fractures are unfortunately seen far too often in reptile patients secondary to inadequate husbandry. Fracture stabilization through application of a splint should be employed in patients exhibiting normal bone density on radiographs. Conversely, splinting can be counterproductive in patients with pathologic fracture, as application of the splint can cause further fractures to the limbs. These patients are best confined with strict cage rest. Analgesia should be provided in both cases and any husbandry issues corrected.1,2,7
Reproductive/Urogenital Emergencies
Dystocia is relatively common in captive reptiles and often occurs secondary to poor husbandry, but it can occur even with proper care. Problems may arise at any part of the female reproductive cycle, resulting in preovulatory, postovulatory, obstructive, or nonobstructive dystocia. Unlike with mammals and birds, emergency treatment is rarely necessary. Medical management can be pursued initially, and surgical intervention can be performed if that fails.1,2,6,7
As stated above, dystocia is not considered a true emergency in reptiles. The exception is if it leads to cloacal prolapse. Any cloacal prolapse—reproductive or otherwise—is a medical emergency. Structures often involved in cloacal prolapse include the bladder, phallus, oviducts, colon, or the cloaca itself. Prolapsed tissue must be identified, tissue viability assessed, and possible underlying cause(s) of the prolapse determined at presentation. Anesthesia and analgesia should be provided, and antimicrobial therapy is warranted. Viable tissue should be kept moist with a water-based lubricant until replacement is possible. Sugar, dextrose, or honey can be employed to address tissue edema to aid in prolapse reduction. Placement of stay sutures or a pursestring is recommended to prevent immediate re-prolapse.1,2,6,7
Nonviable prolapses should be assessed as to the feasibility of resection, especially when considering colonic and bladder prolapses. Devitalized prolapses of the phallus can be amputated without concern for urinary disruption in reptiles, as these structures are not involved in urination. Ovarian prolapse usually suggests significant reproductive pathology, and ovariosalpingectomy is recommended.1,2,6,7
Gastrointestinal
Gastrointestinal disease in reptiles is well described, and symptoms include regurgitation, vomiting, constipation, diarrhea, and inappetence. When gastrointestinal disease is suspected, a good place to start is with a microscopic fecal examination to rule out parasitic causes. Both a fecal flotation and a direct wet-mount cytology should be performed on fresh fecal material (<2 hours). Fecal cytology with Gram stain may also be of benefit to evaluate bacterial populations.1,9,10 Culture can be useful, but caution is recommended when interpreting these results due to the presence of a large amount of normal flora within the alimentary canal. Additional diagnostics for the practitioner to consider include diagnostic imaging and laboratory blood testing.18 When available, more advanced diagnostics such as magnetic resonance imaging and computed tomography may also be of use in select cases.1
Diagnostic imaging modalities such as radiology and ultrasonography are often beneficial in diagnosing causes of gastrointestinal disease in veterinary patients. Overall, the reptile digestive system is more difficult to visualize on survey radiographs than in mammalian patients. This difference is due to reptiles having relatively low amounts of internal fat and the relatively close apposition of organs. Regardless, the dorsoventral view will provide the best visualization of the alimentary system in chelonians and lizards. The lateral view is preferred in snakes. Some amount of intestinal gas is common in lizards, but less so in snakes and chelonians. Radiopaque foreign material may be identifiable, or enlargement of the alimentary canal can be a sign of an obstructive process. However, a prominent gas obstructive pattern is not always seen, and enlargement may also occur due to functional obstruction from ileus. Contrast procedures may be required to document occult cases of obstruction or foreign bodies. The prolonged gastrointestinal transit time documented in reptiles should be taken into account, as it may take several days for contrast agents to move through the alimentary tract.1 Ultrasonography can be used to visualize the gastrointestinal tract of reptiles in which it can be a useful tool in detection of radiolucent foreign bodies or impacted ingesta. Changes in motility can also be observed. Intestinal wall layers can be evaluated in larger patients with the proper frequency transducer. However, large amounts of gas may interfere with this imaging modality, and overall visualization may be extremely challenging with smaller reptile species.1
While findings on laboratory blood analyses are rarely directly indicative of gastrointestinal disease, they can provide valuable insight. Leukograms on patients with gastrointestinal inflammation are typically characterized with heterophilia and monocytosis. Anemia may be seen in chronic cases as well. Biochemical abnormalities can be seen with gastrointestinal disease as well. Frequent changes seen in patients with vomiting, regurgitation, or diarrhea include decreases in blood protein and electrolyte levels. Elevations in aspartate aminotransferase (AST) and creatine phosphokinase (CPK) may also be seen associated with inflammation or damage to the gastrointestinal smooth muscle.1
Etiologies resulting in pathology of the alimentary tract include degenerative disease, gastrointestinal obstruction, chronic dehydration, metabolic derangement, suboptimal nutrition, neoplasia, trauma, toxicosis, viral or bacterial infection, and parasitism. Few degenerative gastrointestinal conditions have been described in reptiles and typically describe an atrophic process of some degree. Atrophic gastritis has been described in both the Hermann’s tortoise (Testudo hermanni) and red-eared sliders (Trachemys elegans). Both cases were characterized by atrophy of the glands within the stomach mucosa, and all clinical signs were related to anorexia. Renal disease can result in mineralization of the gastric muscular tunics subsequently leading to edema, inflammation, and glandular atrophy. Atrophy can also occur in animals during prolonged periods between feedings; re-feeding leads to resolution.11,12
Gastrointestinal obstruction is well documented in reptile patients and can occur from ingestion of foreign material, constipation, neoplasia, or parasitic impaction. Parasitic impaction is relatively uncommon, but it can occur in cases of extremely high parasite loads. Foreign body ingestion is fairly common in reptile patients, especially the ingestion of inappropriate substrates.11,12 Herbivorous chelonians have also been documented as ingesting woody objects with some frequency.9 Constipation is commonly seen in those with reduced motility, functional obstructions, or chronic dehydration. It may also be seen with cystic calculi and renal hyperplasia, where either results in compression of the caudal large intestine or rectum. Both gastrointestinal neoplasia and extra-alimentary masses can result in gastrointestinal obstruction by way of either direct blockage or compression of the intestinal lumen. Anorexia and constipation are seen in females secondary to folliculogenesis as the enlarged reproductive tract decreases the space within the coelom, causing compression on the alimentary tract.11 Intestinal intussusception has been reported in iguanas (Iguana iguana), chameleons (Chameleon spp.), and blue-tongued skinks (Tiliqua scincoides).11,12 A 360° volvulus causing obstruction was documented in a hawksbill turtle (Eretmochelys imbricate).12 Diagnosis of gastrointestinal obstruction relies on imaging such as radiography. Treatment of obstruction relies on resolution of the primary cause by way of either surgical correction or supportive care and medical management for partial obstructions and primary constipation. Fecal impaction that does not resolve with medical management alone requires surgical intervention.11
Primary gastrointestinal neoplasia has been reported in all different species of reptiles, and it can be challenging to diagnose even with extensive diagnostic testing. Associated clinical signs are nonspecific and may include poor growth, anorexia, vomiting, coelomic distention, melena or hematemesis, constipation, dysphagia, ptyalism, and palpable masses. Radiography and ultrasound can aid in diagnosis. However, definitive diagnosis requires either cytology via fine-needle aspirate or surgical biopsy.1 Common neoplasias of the alimentary tract include adenomas, adenocarcinomas, carcinomas, papillomas, leiomyosarcomas, and sarcomas.11 Size, location, and type of neoplasia determine treatment options that may include surgical removal, radiation therapy, and chemotherapy.9
The most common nutritional cause of gastrointestinal disease in reptiles is found as a sequela to nutritional secondary hyperparathyroidism. Hypocalcemia causes reduced gastrointestinal motility resulting in ileus, gaseous distension, anorexia, constipation, and colonic prolapse in some instances. Resolution of gastrointestinal signs typically occurs with resolution of the hypocalcemia. Inappropriate diets may also result in gastrointestinal pathology. Reptiles may develop diarrhea when fed diets too low in fiber. This disorder is most commonly documented in herbivorous reptiles when low-fiber diets cause disruption of the fermentation cycle, bloating, and dysbiosis resulting in lactate-induced diarrhea. Dietary correction often leads to resolution of clinical signs.11
Gastrointestinal toxicosis is infrequently seen reptile patients. Lead toxicosis has been documented in Greek tortoises (Testudo graeca) and alligators after ingestion of lead shot. Ingestion of toxic invertebrates, such as fireflies (Photinus spp.), are also well documented in reptiles. Gastritis may also occur iatrogenically after treatment with nonsteroidal anti-inflammatory medications or corticosteroids. As with toxicosis in other species, treatment is specific to the toxin ingested and coupled with appropriate supportive care.1
Various infectious agents can result in gastrointestinal disease in reptiles. Bacterial gastroenteritis can occur secondary to disruption of the normal flora that forms a protective barrier within the alimentary canal. Factors such as inappropriate diet, stress, antimicrobials, and any disease disrupting absorption of nutrients play a key role. Common isolates are primarily gram-negative, such as Escherichia coli, Pseudomonas spp., Serratia spp., Aeromonas spp., Citrobacter spp., Pasteurella spp., Alcaligenes spp., Proteus spp., and Klebsiella spp. However, other organisms have been isolated, such as Clostridium spp., Mycobacteria spp., Staphylococcus spp., and Corynebacterium spp.1,11 For example, Mycobacteria spp. has been reported causing stomatitis in Boa constrictors (Boa constrictor).1 Diagnosis is made by microscopic examination of fecal samples and fecal culture. Fecal cytology should be performed by way of Gram and acid-fast staining. If a clostridial etiology is suspected, toxin identification is recommended. Treatment involves hydration, supportive therapy, dietary optimization, and broad-spectrum antibiotic therapy based on culture and sensitivity results.1,11
Adenoviral enteritis has also been documented in crocodilians and rosy boas (Lichanura trivirgata).1,11 Adenoviral infections have been identified in other species of reptile with gastrointestinal clinical signs, yet it is not always clear whether it is occurring as the primary pathogen. Reovirus was associated with acute necrotizing colitis in a group of six juvenile Arizona mountain kingsnakes (Lampropeltis pyromelana) that responded to supportive care and antibiotic treatment for secondary bacterial invasion. Herpesvirus was found to be the cause of illness in two monitor lizards (Varanus spp.) with multifocal necrosis of the lamina propria of the small intestine and liver.1,12 Inclusion body disease (IBD) in snakes, a disease recently confirmed to be caused by an arenavirus, has been long documented as a cause of chronic regurgitation, anorexia, and weight loss usually accompanied by the hallmark neurologic disease. Stomatitis is also seen with some frequency in IBD-positive snakes.1 No specific treatment exists at this time specifically for treatment of viral gastrointestinal disease.1,12
Gastrointestinal parasitism is the most common etiology observed in clinical reptile practice.14 It is estimated that virtually 100% of wild reptiles harbor at least one kind of parasite.15 The presence of a parasite alone does not necessarily result in clinical disease.15,16 Prior to determining that an organism is truly parasitic, one must establish that the organism is known to cause pathogenicity and that it is causing damage in some way to the host, either directly or by interfering with various metabolic functions.16 Other factors contributing to pathology include stress, inappropriate environmental temperatures, hygiene, concurrent disease, parasitic load, nutritional status, and age.15,16 Superinfection—marked increases in parasite population density—can play an important role in parasite virulence. Ancillary diagnostics, such as complete blood count and blood biochemical analysis, can be a useful tool in assessing virulence.16 Parasites with direct lifecycles tend to be more of a concern in clinical practice due to lack of availability of intermediate hosts for parasites with indirect lifecycles.15 Clinical signs associated with parasitic infestation arise from the parasite directly competing for nutrients, removing tissue or blood from the host, vascular or lymph obstruction, tissue damage and ulceration, tissue necrosis, inflammation, and edema. Few parasitic diseases cause pathognomonic clinical signs. Definitive diagnosis of parasitism is made by identification of the organism either by direct visualization, microscopy, or detection with polymerase chain reaction analysis.15,16
Neurologic
Common neurologic emergencies in reptile patients include acute ataxia, paresis or paralysis, seizures, or muscle fasciculations. As with mammalian patients, laboratory blood analysis and imaging should follow a thorough history and physical examination. The most common causes of neuropathies in reptiles include nutritional secondary hyperparathyroidism, intoxications, trauma, end-stage renal disease, and envenomations. Treatment is dependent on the underlying cause and severity of the condition.1
Respiratory
Most respiratory emergencies in reptiles are the result of chronic, often untreated illness. True acute respiratory emergencies are rare and result from airway obstruction and drownings.1 Dyspnea needs to be differentiated from panting or behavioral posturing.2 Dyspnea can be primary or secondary to pulmonary compression from intracoelomic fluid or masses. Compensatory respiratory alkalosis is also seen in reptiles suffering from severe metabolic derangements.1 Blood testing and imaging should be utilized to determine the underlying cause.2 Oxygen supplementation should be provided when necessary. Drowning patients presenting in respiratory arrest often will respond to CPCR and positive-pressure ventilation following drainage of fluid.1
Other Emergency Presentations
As discussed earlier, it is not uncommon for reptiles to present on an emergency basis with manifestations of chronic illness, such as septicemia or renal failure. These animals may present obtunded to moribund with varying degrees of weight loss. Diagnosis and prognosis should be determined with laboratory testing and imaging, with appropriate treatment to follow.1,2
Conclusion
Reptiles present on emergency for a number of reasons, whether a true emergency or perceived as one by the owner. While acute emergencies are not commonplace in reptile medicine, it is important to be prepared for them. A thorough understanding of reptiles as patients coupled with proper patient assessment allows the practitioner to best utilize available therapeutics to result in the most favorable outcomes possible.
References
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