Abstract

A 9-year-old female Atlantic bottlenose dolphin (Tursiops truncatus) living in a natural saltwater lagoon presented with vaginal discharge after having a moderately elevated erythrocyte sedimentation rate (range 16–35). During a vaginal swab, a mineral structure was seen in the vagina.

Ultrasound revealed a large (∼10x4 cm), elongated, sharp-shadowing structure within the caudoventral abdomen near midline. It was consistent with a large vaginal calculus, as the mineral was contained within a layered tubular structure directly caudal to the cervix. Although vaginal calculi have previously been described at necropsy in several small cetaceans, to our knowledge, this is the first report in a live dolphin under managed care.^1–7 Causes of vaginal calculi in cetaceans are suspected to include vaginal plugs from coagulated seminal fluid, mammalian bone remnants/aborted embryo, bacterial infections, and cestode Monorygma sp.^1–8 In humans, vaginal calculi are rare, with possible origins of urine stasis, foreign body, vesicovaginal fistula, ectopic ureters, neurogenic bladder with incontinence, or vaginal outlet obstruction.³

Abdominal radiographs and initial extraction were performed with sedation (diazepam 0.18 mg/kg PO) and topical analgesia (2% lidocaine/0.5% bupivacaine) on a foam pad. Radiographs confirmed a large (10x6.2x5.3 cm LxWxH), solid, irregularly shaped mineral opacity. After manual extraction, post-procedural radiographs revealed only the caudal ∼2 cm tip of the calculus had been removed.

Collaboration with a local human urologist allowed for novel use of ultrasonic lithotripsy, in which the vaginal calculus was broken into small pieces for removal. The dolphin was given oral misoprostal 0.74μg/kg, oral diazepam 0.15 mg/kg, and topical 2% lidocaine /0.5% bupivacaine jelly for the procedure. The ShockPulse-mSE with the SPL-PDBX376 probe (Olympus) was used. This lithotripsy system was chosen due to its safety margin, size of the calculus, and expertise of the urologist. Ultrasonic lithotripsy, as well as ballistic lithotripsy, was found to be the safest of the intracorporeal techniques, as it minimizes damage to surrounding tissues compared to laser or electrohydraulic lithotripsy.⁹ Vaginoscopy confirmed complete stone removal.

The largest piece of the calculus cultured Shewanella spp. and Morganella morganii (University of Minnesota Veterinary Diagnostic Laboratory), and on stone analysis, composition was majority struvite with minor calcium phosphate carbonate components (Minnesota Urolith Center). Urine collected via urinary catheter demonstrated no growth on culture (IDEXX, Micrim). Struvite calculi commonly form due to infection with urease-producing microbes, often in urine supersaturated with magnesium ammonium phosphate hexahydrate, which is unlikely in healthy dolphins.^3,10

Although there was no indication of urinary tract infection, it could have been an inciting cause that resolved, or a false negative result. There have been no documented pregnancies in this animal, however she has cohabitated with males. It is also unknown if the calculus formed in situ, or developed in the lower urinary tract and became trapped in vaginal lumen. Further diagnostics are still needed to rule-out anatomic anomalies, including abdominal computed tomography with contrast.

We recommend vaginal examinations in female dolphins in routine physical exams, particularly when an unidentified cause of inflammation is present.

Acknowledgements

The authors would like to thank the animal care trainers at Dolphins Plus, in particular Mary Lou Wright. We also would like to thank the entire urology team, especially Sean Conley and Giuseppe Maurici. In addition, also Dr. Shelby Loos, Dr. Sharon MacIvor, and Dr. Johanna Mejia-Fava for assistance with procedures, Steve McCulloch for photography, and Dr. Thomas Reidarson, Dr. Todd Robeck, Dr. Todd Schmitt, and Dr. Lydia Staggs for advice.

Literature Cited

1.  Benirschke K, Henderson J, Sweeney J. 1984. A vaginal mass, containing fetal bones, in a common dolphin, Delphinus delphis. Rep Int Whal Commn Spec Issue 6: 457–458.

2.  Danil K, Dennison S, Wurster E, Garner M, Lulich J, St. Leger J. 2019. Renal and vaginal calculi in a free ranging long-beaked common dolphin Delphinus capensis. Dis Aquat Org. 136: 265–271.

3.  McFee W, Osborne C. 2004. Struvite calculus in the vagina of a bottlenose dolphin (Tursiops truncatus). J Wildl Dis. 40 (1): 125–128.

4.  Norman S, Garner M, Berta S, Dubpernell S, Klope M. 2011. Vaginal calculi in a juvenile harbor porpoise (Phoceoena phocoena). J Zoo Wildl Med: 42(2): 335–337.

5.  Sawyer J, Walker W. 1977. Vaginal calculi in the dolphin. J Wildl Dis. 13(Oct): 346–348.

6.  Van Bressem MF, Van Waerebeek K, Siebert U, Wünschmann A, Chávez-Lisambart L, Reyes JC. 2000. Genital diseases in the Peruvian dusky dolphin (Lagenorhynchus obscurus). J Comp Pathol. 122: 266–277.

7.  Woodhouse C, Rennie C III. 1991. Observations of vaginal calculi in dolphins. J Wildl Dis. 27(3): 421–427.

8.  Harrison, R.J. 1969. Reproduction and reproductive organs. pp 253–342. In H.T. Andersen (ed.). The Biology of Marine Mammals. Academic Press, N.Y. and London, 511.

9.  Piergiovanni M, Desgrandchamps F, Cochand-Priollet B, Janssen T, Colomer S, Teillac P, Le Duc A. 1994. Ureteral and bladder lesions after ballistic, ultrasonic, electrohydraulic, or laser lithotripsy. J Endourol. 8(4): 293–299.

10.  Ferrandino M, Pietrow P, Preminger G. 2012. Evaluation and medical management of urinary lithiasis, pp 1287–1323. In Campbell-Walsh Urology, 10th ed. Elsevier Saunders Inc, Philadelphia.