What is Vaginal Prolapse/Hyperplasia and How Does it Arise?
Vaginal prolapse/hyperplasia occurs uncommonly, usually during proestrous and oestrous, as a result of fluidy enlargement of vaginal tissue. 360o protrusion of the tissue lining the vagina may occur in vaginal prolapse. In case of vaginal hyperplasia, the problem originates from a stalk of vaginal floor lining.
Fluidy swelling of the vaginal lining is due to the elevated levels of the hormone oestrogen that occur during a normal oestrous cycle.The prolapses that are sometimes seen occur when increased oestrogen levels are produced during the season or when there is weakness of the vaginal connective tissue. The amount of swelling and prolapse is variable and only in severe cases does the tissue actually protrude from the vulva. As vaginal prolapse occurs, the prolapsed tissue promotes further straining which in turn increases the amount of prolapsed tissue. The prolapsed tissue often becomes abraded and ulcerated and in some cases can become necrotic. In the case of normal breeding the oedematous tissue obstructs the ability of the bitch to successfully mate with another dog.
Normally the prolapse or hyperplasia resolves at the end of the season when the ovarian production of oestrogen elapses. However, the prolapse may recur in each succeeding season.
How can Cases of Prolapse/Hyperplasia be Detected?
Vaginal prolapse/hyperplasia occurs most commonly in large breed dogs, especially in young bitches (2 years or younger) during their first three seasons.
Bitches with vaginal hyperplasia but no prolapse usually refuse to allow the male to penetrate during mating. In the case of vaginal prolapse a mass is seen protruding from the vulva. The surface of prolapsed tissue is smooth, swollen, pale pink and glistening when the prolapse is fresh but it will appear dry, dull, corrugated and sometimes ulcerated after having prolapsed for a few days.
How Can Cases be Treated?
The prolapsed tissue will resolve itself when the oestrogen influence diminishes after the season if the protrusion is not circumferential (i.e. 360o). The season may be shortened by administering gonadotropin releasing hormone or human chorionic gonadotropin.
Dogs with vaginal prolapse/hyperplasia must not be used for breeding as the problem can be passed to the offspring. Artificial insemination can be utilised if the bitch is considered valuable and will not allow intromission.
Desexing is recommended to prevent the recurrence and subsequent injury to the everted tissue. Ideally desexing is to be conducted when the bitch is out of season. Repositioning of the everted tissue and placement of purse string suture around the edges of vulva to prevent further prolapse are required while waiting for the ceasation of season. The prolapsed swollen tissue usually reduces in size when the season is complete. Removal of the purse string suture can then be performed and the bitch can be desexed at any time.
Resection of the prolapsed tissue is not recommended as it is often associated with significant bleeding and does not prevent recurrence during subsequent seasons.