Topics in Medicine and SurgeryTopics in Medicine and Surgery

Problem Solving in Reptile PracticePaul M. Gibbons, DVM, MS, Dip. ABVP (Avian),

and Lisa A. Tell, DVM, Dip. ABVP (Avian), Dip. ACZM

bandry con

202

Abstract

Problem-oriented reptile medicine is an explicit, definable process focused on theidentification and resolution of a patient’s problems. This approach includes gatheringcase information, clearly defining the problems, making plans to address each prob-lem, and following up with the case over time. Case information and publishedliterature serve as evidence to support clinical decisions and pathophysiological ratio-nale. This article describes the problem-solving process used to diagnose and treat agreen iguana (Iguana iguana) that presents with ovostasis. © 2009 Published by ElsevierInc.

Key words: evidence-based veterinary medicine; follicular stasis; green iguana;Iguana iguana; preovulatory ovostasis; problem-oriented veterinary medicine

Problem-oriented veterinary medicine is a logi-cal process directed toward the explicit iden-tification and resolution of a patient’s prob-

lems. A complete, problem-oriented, veterinarymedical record includes evidence about the case, aproblem list, plans, and progress notes. Each prob-lem is described at the highest possible level of di-agnostic refinement, and plans are developed toaddress each problem. This process is repeated overtime during patient reevaluations until the problemresolves, an etiologic diagnosis is identified, or both.The purpose of this article is to illustrate problemsolving in reptile practice by describing the medicalevaluation and treatment of a green iguana (Iguanaiguana) with ovostasis.

Information Gathering

Problem-oriented case management begins by col-lecting evidence about the case. Many clinicians di-vide case information into subjective and objectiveevidence, although this division is only useful toacknowledge the level of diagnostic refinement. Sub-jective evidence is descriptive and includes the pre-senting complaint(s), medical history, pertinent hus-

cerns, and physical examination findings.

Journal of E

Objective evidence is quantitative and includes vitalsigns and the results of laboratory tests. A case sum-mary is limited to information that is pertinent tothe problems, but the problem-oriented, veterinarymedical record includes a complete record of allinformation related to the case.

For purposes of illustration, the case described inthis article involved a 2.2-kg green iguana of unknownage that was determined to be female by observation ofsecondary sex characteristics. The current owner hadobtained the animal 3 weeks before presentation.Chief complaints included presumed ovostasis for 15weeks, no defecation for 3 weeks, and burn wounds onthe palmar and plantar surfaces of 3 weeks’ duration.

From the Exotic Species Specialty Service, Animal EmergencyCenter and Specialty Services, Glendale, WI USA, and the De-partment of Medicine and Epidemiology, School of VeterinaryMedicine, University of California, Davis, Davis, CA USA.

Address correspondence to: Paul M. Gibbons, DVM, MS, Dip.ABVP (Avian), Exotic Species Specialty Service, Animal Emer-gency Center and Specialty Services, 2100 W. Silver Spring Dr,Glendale, WI 53201. E-mail: pmgibbons@gmail.com.

© 2009 Published by Elsevier Inc.1557-5063/09/1803-$30.00

doi:10.1053/j.jepm.2009.06.013

xotic Pet Medicine, Vol 18, No 3 ( July), 2009: pp 202-212

Problem Solving in Reptile Practice 203

The iguana had never laid eggs and was not in abreeding program. The primary care veterinarian hadpresumptively diagnosed ovostasis 15 weeks before pre-sentation based on the presence of soft tissue masses inthe reproductive tract that were observed on radio-graphic images. The owner reported that the iguanahad become progressively anorectic during the courseof illness. For treatment, the owner had provided alitter pan with moist soil as a potential nesting site, butdid not observe nesting behavior. The burns occurredwhen the iguana escaped from its cage and was discov-ered in direct contact with the heating element on topof another iguana’s enclosure. These wounds werebeing treated by the primary veterinarian with ceftazi-dime (20 mg/kg intramuscularly every 72 hours, Fortazinjectable; GlaxoSmithKline, Research Triangle Park,NC USA), silver sulfadiazine cream (Thermazine, King

TabAssay Result 28 Jan

Uric Acid 4Total Calcium 121.2Ionized Calcium 1.51Phosphorus 39.6Glucose 296Total Protein 9.2Albumin 1.6Globulin 7.6AST 64Creatine Kinase 3342Lactate Dehydrogenase 145Cholesterol 704Blood Urea Nitrogen 2RBC 1.04Hemoglobin 8.1PCV 31.5MCV 302.9MCH 77.9MCHC 25.7RBC Morphology Slight anisoWBC 11000Bands 550Heterophils 7040Lymphocytes 1980Monocytres 880Eosinophils 110Basophils 440Thrombocytes AdequateRefractometer plasma protein 10.7Plasma fibrinogen 200Icterus index Moderate

Pharmaceuticals, Inc., Bristol, TN USA) applied topi-cally to the affected areas, and bandages. The owner’sdescription of thermal gradient, light quality, humidity,water provision, caging, and diet were appropriate forthe species, but information about husbandry beforeacquisition 3 weeks before presentation was not avail-able. The owner was concerned that the iguana mightrequire surgery because the eggs did not appear to beresorbing after more than 3 months, and he had notobserved the animal defecating over a 3-week period.The only notable external physical examination find-ings included a mildly distended abdomen and full-thickness ulcerations on the palmar and plantar sur-faces of the distal limbs.

The diagnostic screening protocol included acomplete blood count and plasma biochemicalpanel. The results are presented in Table 1 under

.Result 02 Feb Reference Range Unit

ND 1.2-2.4 mg/dLND 8.8-14 mg/dLND 1.37-1.58 mmol/LND 1.3-3.0 mg/dLND 169-288 mg/dLND 5.0-7.8 g/dLND 2.1-2.8 g/dLND 2.5-4.3 g/dLND 5.0-52 IU/LND 0-3995 IU/LND 0-1091 IU/LND 0-437 mg/dLND 0-4 mg/dL

1.06 1.0-1.9 106/ul8.2 6.0-10.0 g/dL

38 25-38 %358.5 165-305 fl77.4 48-78 pg21.6 20-38 g/dL

Slight aniso11000 3,000-10,000 cells/uL

0 cells/uL5390 350-5,200 cells/uL4730 500-5,500 cells/uL

440 0-100 cells/uL0 0-300 cells/uL

440 0-500 cells/uLAdequate

9.5 g/dL400 mg/dL

Slight

le 1

204 Gibbons and Tell

the 28 January heading with reference ranges.1-3

Reference ranges were selected by reading theprimary references to determine how this patientbest matched the study populations in terms ofage, sex, and husbandry conditions. Orthogonalradiographic views of the body were taken to eval-uate the current status of the previously diagnosedovostasis and revealed a cluster of round, 1.0 to 1.5cm, nonmineralized, soft-tissue masses in the cen-ter of the caudal third of the coelom (Figs 1and 2).

Whenever necessary, published information isused to learn background information about anat-omy, physiology, behavior, and husbandry. Thenforeground information is sought to answer ques-tions about diagnostic test interpretation, pathophys-iological rationale, treatment plans, and prognosis.The utility of published information must be ap-praised in terms of veracity and applicability to thecase at hand. For example, in this case, text-books,1,4-12 conference proceeding abstracts/manu-scripts,13-15 roundtable discussions,16 narrative reviewarticles,17,18 and journal articles2,3,19-23 were used to

Figure 1. Dorsoventral radiographic projection of the coelom of anadult female green iguana (Iguana iguana) with a 15-week history ofreduced appetite and lack of defecation for 3 weeks. Note the clusterof round, soft-tissue-density masses filling the caudal one third ofthe coelomic cavity (arrows).

answer the clinician’s background and foreground

questions. No single electronic search engine willoffer a complete search of all available publishedliterature. Textbooks on herpetological medicinemay be borrowed from veterinary school libraries orpurchased from the Internet or veterinary booksell-ers. Useful online search engines include PubMed(no fee), ISI Web of Knowledge (subscription re-quired), BioONE (no fee), and Google Scholar (nofee). Figures 3, 4, 5, and 6 demonstrate the differentresults obtained when searching these databases us-ing the keyword “dystocia” together with either “rep-tiles” or “reptil*”. The PubMed (http://www.ncbi.nlm.nih.gov/pubmed) database includes articlespublished in many bioscience journals, and, al-though it is available at no charge to the user, itexcludes important sources of evidence in herpeto-logical medicine (Fig 3). ISI Web of Knowledge is anumbrella of databases that includes PubMed, CABDirect, Zoological Record, Web of Science, and BIOSISpreviews (Fig 4). It can be accessed at Thomson (ISI)Web of Knowledge (http://www.isiwebofknowledge.com) and allows searching of some additionalsources of information that are important to herpe-tological medicine including both the Journal of Her-petological Medicine and Surgery and the Proceedings ofthe Annual Conference of the Association of Reptilian andAmphibian Veterinarians. BioONE (http://www.bioone.org/search) includes a number of journals notfound in PubMed, including Copeia, Current Herpetol-ogy, Herpetologica, and Journal of Herpetology. It pro-vides access to important background information;in this case, however, it did not identify a source ofinformation on reptile dystocia (Fig 5). GoogleScholar (http://scholar.google.com) includes a widearray of periodicals and textbooks, allows simple oradvanced use of search terms, and allows cross-ref-erencing of citations (Fig 6). In addition, VeterinaryInformation Network (http://www.vin.com) has asearchable library that offers free abstracts of articlesfrom many relevant veterinary journals and full text

Figure 2. Horizontal-beam lateral radiographic projection of thecoelom of the same green iguana in Figure 1. Note the generallyuniform soft-tissue-density region filling the mid-caudal coelom(white arrows) and displacing the gastrointestinal tract cranially and

dorsally (black arrowheads).

Problem Solving in Reptile Practice 205

Figure 3. Computer screen image of the search results on PubMed (http://www.ncbi.nlm.nih.gov/pubmed) showing the results of a searchon the keywords “dystocia” and “reptiles.” Thirteen publications were found; note that search results using other keywords returned fewer

results.

n in

206 Gibbons and Tell

of many conference proceedings articles. Download-ing published articles from the Internet is availablevia these search engines for a fee, and may be al-

Figure 4. Computer screen image of the search results with theKnowledge search engine (http://www.isiwebofknowledge.com). Nojournals not included in the results from the PubMed website show

lowed with an individual subscription to that journal

or database, membership in an affiliated organiza-tion, or personal affiliation with a university. In somecases, articles must be obtained by physically visiting

ords “dystocia” and “reptil*” using “all databases” in the Web ofat the results include many conference proceedings, articles, andFigure 3.

keywte th

a local or university library and placing an order.

Problem Solving in Reptile Practice 207

Figure 5. Computer screen image of the search results of BioONE (http://www.bioone.org/search) using the keywords “iguana” and “repro*”because no articles were identified using a search using “dystocia” and “reptile*” and 982 articles were found using “repro*” and “reptile*”.

Note that the titles are of articles describing natural history and free-ranging lizards.

208 Gibbons and Tell

Figure 6. Computer screen image of the search results with the keywords “dystocia” and “reptiles” using Google Scholar (http://scholar.google.com). Note that 247 publications were identified. These results include many of the publications that were identified using the

search engines depicted in Figures 3, 4, and 5 as well as references within publications.

Problem Solving in Reptile Practice 209

Problem Definition

Problem ListIt is important to avoid overstating problems, andrule-outs should not be included in the problem list.Problems should, however, be stated at the highestpossible level of diagnostic refinement based on jus-tifiable rationale and evidence. The levels of diag-nostic refinement include: (1) subjective evidence,(2) objective evidence, (3) pathophysiological syn-drome, and (4) etiologic diagnosis. For example, theinitial problem list in this case includes burn woundsand ovostasis. The etiologic diagnosis of burnwounds is supported by the history, current exami-nation findings, and inflammatory leukogram. Thepathophysiological syndrome of ovostasis is sup-ported by: (1) the history of decreased appetite,decreased defecation, and radiographic interpreta-tion of coelomic images from the primary veterinar-ian, (2) physical examination findings, (3) mildhyperuricemia, (4) marked increase in nonionizedcalcium with hyperphosphatemia and hyperglobu-linemia, (5) hypercholesterolemia, and (6) currentradiographic findings of multiple, round, soft-tissue-density structures in the mid coelom.

Problem Planning

The plan for the burn wounds was not altered fromthat prescribed by the primary veterinarian, so thisproblem is not discussed further in this article.

Diagnostic Plan for OvostasisOvostasis is a pathophysiologic syndrome. It can beattributed to many different causes, and the differ-ential diagnosis list will differ depending on whetherthe ovostasis is preovulatory (follicular stasis) or pos-tovulatory (dystocia). The algorithm in Figure 7 isused to determine whether the ova are preovulatoryor postovulatory. In this case, no eggs had beenoviposited (laid), the ova were not mineralized onradiographic images, and the ova were clustered.Further imaging was necessary to differentiatewhether the ova were preovulatory or postovulatory,so coelomic ultrasound was scheduled 5 days afterinitial presentation.

Treatment Plan for OvostasisInitial empirical therapy for ovostasis was not depen-dent on whether the ova were preovulatory or pos-tovulatory. The treatment plan included subcutane-ous crystalloid fluids (30 mL/kg subcutaneous every

72 hours, lactated Ringer’s solution); continued

daily soaking in shallow (�5 cm), tepid (25°C-30°C)water for 15 minutes every 24 hours; and continuedceftazidime (20 mg/kg intramuscularly every 72hours) administration as prescribed by the primaryveterinarian for the burn wounds.

Client Education Plan and PrognosisSome of the causes of ovostasis that are described inthe above literature include husbandry concernssuch as nutritional deficiencies, inappropriate heatprovision, lack of basking sites, inadequate UVBspectrum light, and dehydration caused by insuffi-cient humidity or water provision. Informationabout the best possible husbandry practices forgreen iguanas was discussed with the client becauseit can be difficult to determine with certainty thathusbandry problems exist. The owner was directedto www.anapsid.org, which is the source that theauthors rely on for green iguana care information,even though the information is generally not scien-tific. In addition, the client’s concern that ovostasis islikely to be a serious health concern after more than3 months and that ovariosalpingohysterectomy maybe necessary to resolve the current problem andavoid future reproductive problems was validated.The nest box was maintained during the interimbefore diagnostic ultrasound to provide continuedopportunity for oviposition in case the ova werepostovulatory. A good prognosis was reported to theclient because the patient was in good body condi-tion, and complicating disease factors were not evi-dent. This prognosis was based on recollection of theoutcomes of similar cases and textbook informa-

Figure 7. Problem-solving algorithm for a reptile with presumedovostasis.

tion.6,8,12

210 Gibbons and Tell

Follow-up

Primary Follow-up Information GatheringThe patient was presented again as scheduled, 5 daysafter the initial presentation. The owner reported nochanges in the animal’s behavior, appetite, or defe-cation since the last visit. The only change noted inthe physical examination findings was tacky saliva.The results of a recheck complete blood count(CBC) included heterophils decreased into refer-ence range, increasing lymphocytes, and decreasingmonocytes (Table 1). Coelomic ultrasound revealedvariably echogenic, round structures clustered in themid coelom and a moderate amount of flocculentcoelomic fluid.

Primary Follow-up AssessmentThe recheck CBC was consistent with resolvinginflammation. Ultrasonic examination of the coe-lom was consistent with multiple caseated ovarianfollicles and a diagnosis of preovulatory ovostasiswith coelomic fluid. Differential diagnoses for pre-ovulatory ovostasis include inappropriate hus-bandry (see above), improper nesting site, stress,hormonal disturbances, infectious oophoritis, eggyolk coelomitis, infectious coelomitis, and oviductobstruction. Husbandry concerns were being ad-dressed, a nesting site had been provided, andstressors were minimized to the best of the owner’sability. In this case, a problem-solving algorithmfor preovulatory ovostasis led to exploratory sur-gery as the next diagnostic step (Fig 8). Explor-atory surgery provides an opportunity to examinethe coelomic cavity, collect diagnostic samples,and resolve the problem by removing the pairedovaries, oviducts, and uteri. Hormonal distur-bances would not be addressed in this case be-cause this animal was not intended for breeding.

Primary Follow-up PlansCoelomitis, a new problem, was identified duringsurgery. Findings included diffuse serosal fibrindeposition; moderate, diffuse, fibrinous, flocculent,beige coelomic fluid; necrotic ovarian follicles; andfree-floating inspissated yolk-like material (Fig 9).Both ovaries and oviducts were removed with hemo-clips because of the adherent fibrin and debris. Thecoelomic cavity was explored and thoroughly la-vaged with sterile saline solution. Tissue sampleswere collected for histopathological characterizationof inflammation and cultures to differentiate be-tween infectious and egg yolk causes of coelomitis.

Therapeutic plans included butorphanol (1 mg/kg

intramuscularly every 24 hours for 7 days, Torbug-esic; Fort Dodge Animal Health, Fort Dodge, IAUSA), ketoprofen (1 mg/kg intramuscularly every24 hours for 7 days, Ketofen; Fort Dodge AnimalHealth), 60 mL lactated Ringer’s solution subcu-taneously every 24 hours for 5 days, enrofloxacin(7.5 mg/kg intramuscularly every 24 hours for 7days, Baytril; Bayer Corporation, Shawnee Mission,KS USA), and continued ceftazidime 20 mg/kgintramuscularly every 72 hours. Client educationplans included no soaking for 30 days, restrictedactivity to a small cage, leafy green vegetables start-ing 2 days postoperatively, and continued moni-toring of fecal production. The prognosis was re-ported to the client as fair in cases of ovostasis thatare complicated by infectious coelomitis or sepsis,based on the same sources of evidence as theinitial prognosis. Follow-up imaging and CBC wereplanned in 7 days to ensure that the coelomitiswould be resolving. Further diagnostic and thera-peutic plans would be based on the patient’s re-

Figure 8. Problem-solving algorithm for a reptile with preovulatoryovostasis (follicular stasis).

sponse to treatment.

Problem Solving in Reptile Practice 211

Summary of Continued Follow-upThe patient initially improved for a few weeks butthen declined. No aerobic, anaerobic, or fungal or-ganisms could be cultured from samples collectedduring surgery, and histopathology confirmed a di-agnosis of egg yolk coelomitis. Two remaining inspis-sated masses of yolk material were discovered onfollow-up ultrasound and continued to serve as nidifor coelomitis. Approximately 3 months after initialpresentation, the client declined a second explor-atory surgery to remove the remaining yolk materialand elected for euthanasia. Final diagnoses includedfibrinous and granulomatous egg yolk coelomitis;mild nephritis; moderate endocardiosis; and aorticmineralization with chronic lymphocytic arteritis.

Self-assessment and Learning

This case demonstrates the process of problem solv-ing that was used for a case of follicular stasis and eggyolk coelomitis. The initial good prognosis was basedon unsystematically recorded experiences and text-book reports. These unreliable sources of evidencewere incorrect in this case. Client expectations couldhave been more accurate if more reliable sources ofevidence, such as retrospective studies or case-con-trol studies, had been available to provide moreaccurate probabilities of the possible outcomes. Eggyolk material (vitellin) stimulates an inflammatoryresponse and causes coelomitis. Although not com-plicated by bacterial infection in this case, bactere-

Figure 9. Intraoperative photograph of the coelomic cavity of thegreen iguana described in Figures 1 and 2 through a ventralparamedian incision. Note the beige fluid, the fibrinous materialadherent to the coelomic membranes, and the light brown, discol-ored follicles.

mia can cause secondary infection and contribute to

the disease process. It is plausible that empiricalantibiotic therapy prevented secondary bacterial in-fection. Butorphanol was administered for analgesiaafter surgery. New research evidence has shown thatit has questionable efficacy for analgesia in consciouslizards at the chosen dose (1 mg/mL), so in thefuture a primary mu agonist such as morphine willbe chosen instead.24,25 Blood calcium was measured3 months postoperatively but not before. The attend-ing clinicians relied on pathophysiological rationaleto presume that hypercalcemia was a result of vitel-logenesis instead of gathering case evidence to en-sure there was no other source of hypercalcemia.The authors and all involved personnel learned theimportance of thorough exploration of the coelomiccavity during surgery, because the patient mighthave recovered if no yolk material had remainedafter the exploratory coeliotomy.

Conclusion

This case demonstrated how problem-oriented vet-erinary medicine can be used to confidently decidewhen surgical intervention is necessary for greeniguanas with presumed ovostasis. The case also showshow follow-up evaluation is essential to modify plansaccording to patient response to treatment. In thiscase, the owner eventually elected to euthanize theanimal, a decision that was consciously chosen byintegrating the attending veterinarians’ clinical ex-pertise, the best-available evidence, the client’s val-ues, and the individual patient’s needs.

Acknowledgments

The authors would like to thank Drs Jennifer Gra-ham and Anna Osofsky for their work on the clinicalcase, and Dr James Wellehan for his help in prepar-ing the manuscript.

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