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Pre- / post-ovulatory stasis
Synonym(s): Follicular stasis, Egg binding, Dystocia
Introduction
- Cause: pre-ovulatory stasis occurs when follicles fail to ovulate and become progressively larger. The cause is not fully understood. Post-ovulatory stasis may be obstructive or non-obstructive and is due to a variety of causes.
- Signs: lethargy, anorexia, coelomic enlargement, hindlimb paresis, dyspnea, partial clutch laid.
- Diagnosis: presumptive based on history, exam, imaging and bloods.
- Treatment: pre-ovulatory stasis must be treated by surgical ovariectomy. Post-ovulatory stasis may be treated through husbandry improvements, supportive care, medical induction or surgical salpingotomy or salpingectomy.
- Prognosis: pre-ovulatory stasis where a coelomitis is present carries a guarded prognosis. Post-ovulatory stasis carries a good prognosis depending on the underlying causes.
Presenting signs
- Often non-specific lethargy and anorexia Anorexia.
- Coelomic enlargement, including visible bulging follicles or eggs may be seen.
- Very large follicles may result in dyspnea.
- Chronic disease in tortoises may result in hindlimb paresis.
- Excessive digging with only partial or no clutch produced.
- Blood from cloaca.
Acute presentation
- Animals with ruptured follicles and a yolk coelomitis may present collapsed.
Geographic incidence
- Worldwide in captive reptiles.
Age predisposition
- Any age can be affected.
- In bearded dragons and chameleon species, pre-ovulatory stasis is commonly seen in younger animals.
Breed/Species predisposition
- Seen in all reptile species.
Public health considerations
- None.
- All reptiles may carry Salmonella spp as a normal commensal organism.
Cost considerations
- Husbandry and environmental deficits will need to be corrected and appropriate equipment will likely require expenditure.
- Surgical treatment and hospitalization may be required.
Special risks
- Many of these animals are chronically dehydrated/hypovolemic and should be stabilized first.
- Chronic cases of pre-ovulatory stasis may have reduced lung volume or be septicemic.
Pathogenesis
Etiology
Pre-ovulatory stasis (follicular stasis)
- Etiology is unknown.
- Proposed causes include:
- Suboptimal nutrition Nutritional requirements.
- Secondary nutritional hyperparathyroidism/metabolic bone disease Metabolic bone disease.
- Absence of males.
- Lack of normal seasonal patterns in tortoises.
- Lack of hibernation in tortoises Hibernation.
- Secondary bacterial infection.
Post-ovulatory stasis (dystocia)
- Obstructive causes:
- Oversized eggs.
- Abnormal shaped eggs.
- Egg that has retropulsed into the bladder (chelonia).
- Adhesions to oviduct.
- Urinary calculi or other coelomic space occupying masses.
- Non-obstructive causes:
- Suboptimal environmental temperatures.
- Lack of a suitable nesting area.
- Dehydration.
- Hypocalcemia.
Predisposing factors
General
- Type here
Specific
Pre-ovulatory stasis
- Suboptimal nutrition.
- Secondary nutritional hyperparathyroidism/metabolic bone disease.
- Absence of males.
- Lack of hibernation in tortoises.
- Secondary bacterial infection.
Post-ovulatory stasis
- Suboptimal temperatures.
- Hypocalcemia.
- Dehydration.
- Lack of a nesting area.
- Urinary calculi and other coelomic space occupying lesions.
- Salpingitis.
- Oviduct stricture.
- Abnormally shaped eggs.
- Eggs too large to fit through pelvis.
- Egg in bladder in tortoises.
Pathophysiology
Pre-ovulatory stasis
- Follicles fail to ovulate.
- Follicles increase in size.
- Animal may become inappetent as a result of space occupying mass.
- Secondary infection with commensal bacteria occurs.
- Follicles rupture releasing yolk.
- Yolk causes inflammation and a yolk coelomitis.
- Death if untreated.
Post-ovulatory stasis
- Obstructive dystocias:
- Eggs physically cannot be passed.
- Eggs are retained.
- Secondary problems develop.
- Non-obstructive:
- Suboptimal temperatures and/or lack of calcium lead to poor uterine contraction and egg retention.
- Lack of a suitable nesting area causes behavioral dystocia.
Timecourse
- Pre-ovulatory stasis is often chronic but may present acutely.
- Post-ovulatory stasis may be acute or chronic.
Epidemiology
- Generally individual cases, however if secondary to environment or nutrition, cases may occur in clusters.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Di Girolamo N & Selleri P (2017) Reproductive disorders in snakes. Vet Clin North Am Exotic Anim Pract 20 (2), 391-409 PubMed.
- Hernandez-Divers S (2010) Reptile diagnostic endoscopy and endosurgery. Vet Clin North Am Exotic Anim Pract 13 (2), 217-242 PubMed.
- Rivera S (2008) Health assessment of the reptilian reproductive tract. J Exotic Pet Med 17 (4), 259-266 VetMedResource.
- Lock B A (2000) Reproductive surgery in reptiles. Vet Clin North Am Exotic Anim Pract 3, 733–752 PubMed.
- Mader D R (1996) Reproductive surgery in the green iguana. J Exotic Pet Med 5 (4), 214–221 JExoticPetMed.
Other sources of information
- Klaphake E, Gibbons P M, Sladky K K & Carpenter J W (2018) Reptiles. In: Exotic Animal Formulary. 5th edn. Ed: Carpenter J W. Elsevier, USA. pp 81-166.
- Mader D R et al (2006) Surgery, Reptile Medicine and Surgery. Saunders Elsevier, USA. pp 581-630.
- McArthur S & Hernandez-Divers S (2004) Surgery, Medicine and Surgery of Tortoises and Turtles. Wiley-Blackwell, UK. pp 403-464.
- Johnson J (2004) Urogneital System. In: BSAVA Manual of Reptiles. Eds: Girling S & Raiti P. BSAVA, UK. pp 261-272.
- Wilkinson R et al (2004) Diagnostic Imaging Techniques, Medicine and Surgery of Tortoises and Turtles. Wiley-Blackwell, UK. pp 187-238.