Читать книгу Blackwell's Five-Minute Veterinary Consult: Reptile and Amphibian - Javier G. Nevarez - Страница 168

Egg Yolk Coelomitis

BASICS

DEFINITION/OVERVIEW

Egg yolk coelomitis occurs when yolk material is released into the coelomic cavity as a result of a ruptured follicle or egg due to oophoritis, follicular stasis, dystocia, salpingitis, or aggressive palpation.

ETIOLOGY/PATHOPHYSIOLOGY

 In all cases, yolk coelomitis is a result of yolk material free within the coelomic cavity overwhelming the body’s activity to resorb the material. This leads to an intense inflammatory response that is often sterile but can also be associated with secondary bacterial infection.

 It can progress to adhesions throughout the coelomic cavity, septicemia, and death.

SIGNALMENT/HISTORY

 Egg yolk coelomitis occurs in female chelonians of reproductive age or size, usually older than 1 year.

 Most animals have a history of inadequate husbandry, being housed alone without access to a male, and lacking an appropriate area for laying eggs or giving birth.

 The majority of cases occur in captive animals, but the author has diagnosed yolk coelomitis in free‐ranging gopher tortoises (Gopherus polyphemus).

CLINICAL PRESENTATION

 Chelonians with yolk coelomitis often present with non‐specific clinical signs such as anorexia and lethargy.

 Other abnormalities identified in physical exam may include hind‐limb weakness/ paresis, dehydration, poor body condition score, and pliable bones.

 Some animals may present obtunded due to rapid progression of the disease.

RISK FACTORS

Husbandry

 Any factors that may result in follicular stasis or dystocia are also contributing factors to yolk coelomitis.

 These include inadequate husbandry, nutrition, brumation, and nesting environment.

Others

 A less discussed topic is the effect that lack of exposure to males may have on the reproductive cycle of reptiles.

 Many reptiles display courtship and breeding behaviors that likely influence the proper hormonal stimulation of prospective females.

 Many female chelonians in captivity are kept alone without the benefit of behavioral cues from a male counterpart.

 This possibility of a behavioral effect must be considered, especially when animals are maintained in proper husbandry and are otherwise healthy.

DIAGNOSIS

DIFFERENTIAL DIAGNOSIS

 Follicular stasis

 Dystocia

 Neoplasia

 Ovarian cysts

 GI obstruction

 Septicemia

DIAGNOSTICS

Cytology

 Evaluation of free fluid in the coelomic cavity will be a confirmatory test of yolk coelomitis. In acute cases, fluid is yellow to white, with a high amount of proteinaceous material and inflammatory cells.

 In chronic cases the fluid may appear cloudier.

 Blood and bacteria may also be observed with either presentation.

Imaging

 Radiography: findings may include free fluid, follicles, or ruptured eggs.

 Ultrasound: aspiration of any free fluid can be used to diagnose egg yolk coelomitis.

 CT scan and MRI: both modalities are extremely sensitive for evaluation of the reproductive tract. They can also help to assess damage to other organs.

Coelioscopy

Coelioscopic examination allows for confirmation of yolk coelomitis but may be confounded by changes in anatomy due to adhesions.

Hematology and Biochemistry

 A chemistry panel is essential to help identify other possible underlying disease processes such as dehydration and NSHP.

 In addition to Ca and P, Mg levels should be documented as Mg also plays an important role in Ca homeostasis.

 Levels of Mg below 1 mg/dl and/or ionized Ca below 1 mmol/l should be considered deficient.

 Hypercalcemia and hyperphosphatemia are common findings in reproductively active female chelonians.

 Hyperproteinemia, anemia, and hypoglycemia may also be identified.

 CBC: leukocytosis may be observed but does not always occur, especially in chronic cases. Leukopenia may be present if sepsis has ensued.

PATHOLOGICAL FINDINGS

 During the acute stages, egg yolk coelomitis presents as yellow to white, viscous, free fluid within the cavity.

 Fragments of more solid yolk may also be free floating within the cavity.

 Chronically more adhesions develop and form a white fibrinous to fibrotic membrane on the serosal surfaces of the organs.

 The lesions are often severe enough that surgical repair is not possible.

 Many cases are diagnosed postmortem.

TREATMENT

APPROPRIATE HEALTH CARE

 Animals with yolk coelomitis must undergo surgery in an attempt to correct the condition, but it is often fatal.

 In most chelonians, yolk coelomitis is a chronic presentation.

 The goal of exploratory coeliotomy is to determine the severity of the diseases and whether successful lavage and cleaning of the cavity can be performed.

 Any free‐floating material must be removed and the cavity lavaged copiously to remove the protein.

 If it can be accomplished, an ovariosalpingectomy is performed.

 Surgery can be performed either through the prefemoral fossa, aided by an endoscope or by plastronotomy.

 A plastronotomy will allow for better lavage and evaluation of the cavity, but it carries a higher risk of postoperative complications.

 Any underlying abnormalities (e.g., NSHP, dehydration, anemia) must be treated accordingly.

 These animals must also receive anti‐ inflammatories and analgesics, as the reaction to the yolk and subsequent adhesions are extremely painful.

NUTRITIONAL SUPPORT

 Dietary deficiencies must be corrected with special emphasis on UVB light and oral Ca supplementation.

CLIENT EDUCATION/HUSBANDRY RECOMMENDATIONS

 Clients should be encouraged to seek veterinary care of chelonians early on to establish individual baseline values and confirm the sex of the animal.

 Egg yolk coelomitis occurs as a sequel to multifactorial causes, so all husbandry deficiencies must be corrected, with emphasis on UVB light, calcium supplementation, nutrition, temperature, humidity, and provision of adequate nesting substrate.

 Chelonians should be weighed at least weekly to document any sudden weight increases that may be indicative of follicular development that may lead to yolk coelomitis.

MEDICATIONS

DRUG(S) OF CHOICE

 Meloxicam 0.5 mg/kg PO, IM, SC q24–48h

 Morphine 1–10 mg/kg IM, SC q24h

 Hydromorphone 0.2–0.5 mg/kg IM, SC q12–24h

PRECAUTIONS/INTERACTIONS

 Morphine and hydromorphone can cause sedation and respiratory depression.

 Dose and frequency of administration should be refined based on the patient’s response.

FOLLOW‐UP

PATIENT MONITORING

 If an underlying disease process is diagnosed, appropriate follow‐up diagnostics should be performed to determine improvement of that condition or the need to alter therapy.

 A re‐evaluation within 1–2 weeks of surgery is recommended to evaluate the surgical site and overall recovery.

EXPECTED COURSE AND PROGNOSIS

 The overall prognosis will depend on the speed with which the disease is recognized by the owners and diagnosed and treated by the veterinarian.

 Per‐acute to acute cases have a fair prognosis.

 Chronic cases have a grave prognosis.

MISCELLANEOUS

COMMENTS

N/A

ZOONOTIC POTENTIAL

N/A

SYNONYMS

 Egg coelomitis/peritonitis

 Yolk coelomitis/peritonitis

ABBREVIATIONS

 Ca = calcium

 CBC = complete blood count

 CT scan = computed tomography

 GI = gastrointestinal

 IM = intramuscular

 Mg = magnesium

 MRI = magnetic resonance imaging

 NSHP = nutritional secondary hyperparathyroidism

 P = phosphorus

 PO = per os

 SC = subcutaneous

INTERNET RESOURCES

Pollock C. Reproductive disease in reptiles: twelve key facts. LafeberVet, September 23, 2012. https://lafeber.com/vet/reproductive‐disease‐in‐reptiles‐ twelve‐key‐facts

Author Javier G. Nevarez, DVM, PhD, DACZM, DECZM (Herpetology)