Diseases of the Vagina and Vulva

Chapter 92 Diseases of the Vagina and Vulva



Mary A. McLoughlin


Small animals with diseases of the vulva and vagina can present with clinical signs of lower urinary tract disease (urgency, pollakiuria, stranguria, and hematuria), intermittent or continuous urinary incontinence, vaginal discharge, perivulvar dermatitis, excessive licking, and foul odor. Because the vulva and the vestibule form a common orifice for the lower urinary and reproductive systems, careful examination of associated diseases is warranted. See Chapter 93 for discussion of the anatomy of the vagina and vulva.



DISEASES OF THE VULVA



Congenital Abnormalities


Congenital abnormalities of the vulva are uncommon and are often detected because of the secondary problems they cause. Abnormalities of the anatomic structure, size, or positioning of the vulva have been shown to be contributing factors to the development several disorders, including chronic or recurrent urinary tract infections, cystitis, vaginitis, vestibulitis, urine pooling or urinary incontinence, perivulvar dermatitis, and difficulty with natural mating. Diagnosis of vulvar disorders is made by physical examination of the vulva and perivulvar region, as well as digital palpation and vaginoscopy.



Vulvar Hypoplasia or “Juvenile” Vulva



Etiology



• Vulvar hypoplasia has been described as a small or infantile vulva, which is frequently retracted and obscured by the perivulvar skin folds. The patient’s weight or body condition score should not bias the diagnosis of vulvar hypoplasia.

• The vulva should not be covered or obscured by regional skin folds dorsally or laterally. It should not be necessary to pull upward on the perineal skin between the anus and the vulva to expose the complete extent of the vulva.

• Tremendous variation in size, structure, and position of the vulva exists among various breeds of dogs, as well as within specific breed standards. The vulva should be located on the perineal midline directly ventral to the anus. Although the size of the vulva varies among dogs, it should be readily visible in the standing dog when viewed from behind. The vulva should not be positioned ventrally between the rear legs so that it is no longer visible.

• Perivulvar skin folds may obscure both hypoplastic and normal-sized vulvas. There are a number of breeds of dogs that appear to be conformationally predisposed to perivulvar skin folds as young dogs without being overweight, including Newfoundland, Labrador retriever, mastiff, German shepherd, Akita, basset hound, Staffordshire terrier, and bull terrier.

• It is well recognized that the anatomic characteristics of the vulva are altered due to the hormonal influence of the estrus cycle in unspayed females. The vulva becomes swollen and enlarged during proestrus and estrus. As the vulva enlarges, it is generally assumes a more dorsal position in the perineal region to facilitate mating.

• The size of the vulva generally does not change in spayed female dogs. It has been theorized that vulvar hypoplasia results from ovariohysterectomy at an early age prior to development of secondary sex characteristics. However, there is no scientific literature to support this statement.


Clinical Signs



• A small or hypoplastic vulva is common and frequently not associated with any clinical abnormalities. However if the vulva is small and recessed by the surrounding perivulvar skin folds, body heat and moisture from vaginal secretions or urine can accumulate between local skin folds, creating an environment conducive to skin maceration, inflammation, and bacterial overgrowth. Microtrauma to the skin surfaces from friction between the opposing skin folds, combined with tissue maceration and inflammation, causes normal skin defense mechanisms to be overwhelmed, allowing secondary bacterial infections to occur.

• Superficial dermatitis in the perivulvar region can result in a foul odor and discharge.

• Secondary clinical signs of chronic vestibulitis, vaginitis, cystitis, and ascending urinary tract infection have also been reported.


Treatment



• Medical management of perivulvar dermatitis with systemic antibiotics or topical therapies such as antimicrobials, antiseptic, cleansing, or drying agents can be performed (see Chapter 38). However, this approach is typically only palliative and often unrewarding for long-term resolution.

• Episioplasty, the surgical excision of the excessive perivulvar skin folds to expose and reposition a small or recessed vulva, is the treatment of choice for perivulvar dermatitis, chronic or recurrent urinary tract infections, or vestibulitis secondary to ascending infection or chronic local inflammation (see Chapter 54).


Vulvar Stenosis



Etiology



• Abnormal fusion of the genital folds and genital swellings can result in narrowing or stenosis of the vulva, vestibule, or vestibulovaginal junction.

• Vulvar stenosis has been most frequently reported in the collie and Shetland sheepdog breeds.


Clinical Signs



• There are frequently no clinical signs if the affected animal has been spayed.

• This abnormality may be overlooked unless the affected female is intended for breeding or a digital examination of the vulva, vestibule, and vestibulovaginal junction is indicated.

• Affected females may experience pain when mating is attempted, requiring the deposition of semen by artificial insemination.

• If pregnancy does occur, vulvar stenosis can result in dystocia. A planned cesarean section can be performed to avoid this complication, or an episiotomy can be performed at the time of delivery of the first fetus.


Treatment



• Enlargement of the vulvar orifice, rima vulvae, by permanent episiotomy (episiostomy) can be performed (see Chapter 93).

• Increasing the size of the vulvar orifice may result in an increased exposure of the vestibule, vagina, and lower urinary tract to ascending environmental contaminants, resulting in secondary vestibulitis, vaginitis, and urinary tract infection.


Clitoral Hypertrophy


The clitoris is located on the ventral floor of the vulva, normally recessed within the clitoral fossa. The clitoral fossa demarcates the cranial edge of the vulva at the transition of the vulva to the vestibule. The clitoris is described as the female homologue to the penis and may contain an os clitidoris.



Etiology



• Clitoral enlargement is typically associated with any one of a number of developmental or acquired etiologies, including disorders of sexual differentiation (see Chapter 90), exposure to anabolic steroids, or hyperadrenocorticism (see Chapter 33).

• Enlargement of the clitoris may result in exposure of the clitoris by its protrusion through the vulvar cleft.

• Clitoral enlargement has been documented in normal female dogs.


Clinical Signs



• The clinical signs associated with clitoral hypertrophy are variable. Animals may be presented for purely cosmetic reasons rather than specific health concerns.

• Enlargement of the clitoris and exposure through the vulvar cleft can result in clitoritis from environmental exposure, drying, and mechanical irritation.

• Inflammation of the clitoris can also result in secondary urinary tract infection, vestibulitis, or vaginitis with discharge due to drainage around the enlarged clitoris.


Treatment



• Symptomatic therapy with systemic antimicrobials, anti-inflammatory drugs, or local treatment with topical therapies is typically unrewarding for long-term resolution of clinical signs.

• Determination of an underlying etiology is essential to direct treatment at an inciting cause. Withdrawal of all anabolic steroids or treatment of hyperadrenocorticism may result in regression of the clitoral enlargement.



Key Point


Surgical treatment of clitoral hypertrophy is not indicated if a patient does not have any associated clinical signs.



• Perform clitoral resection for patients with persistent clinical signs associated with clitoral enlargement.


Surgical Procedure: Clitoral Resection



Technique


1. Perform an episiotomy to expose the clitoris and clitoral fossa. The external urethral orifice is identified and catheterized (see Chapter 93).

2. Dissect the base of the clitoris, which may include an os, from the fossa and surrounding vulvar and vestibular mucosa using sharp dissection.

3. Control hemorrhage with electrocautery or a laser. Larger “phalluses” present in dogs with intersex disorders may bleed profusely. Control of local hemorrhage is essential.

4. Close the incised edges of the vulvar and vestibular mucosa with a monofilament absorbable suture, eliminating the clitoral fossa.

5. Close the episiotomy in a routine manner (see Chapter 93).


Postoperative Care


• Place an Elizabethan collar to prevent self-trauma.

• Consider administration of nonsteroidal anti-inflammatory drugs after surgery for swelling, pain, and discomfort (see Chapter 6).


Vulvar Enlargement



Etiology



• Edema or swelling of the vulva is a normal response to estrogenic stimulation during the follicular stages of the estrus cycle in intact dogs and cats. Typically, vulvar swelling resolves on its own as the female enters diestrus.

• Persistent or prolonged swelling of the vulva in cycling females may represent prolonged estrogenic stimulation from cystic ovaries or an estrogen-producing ovarian neoplasm, such as a granulosa cell tumor (see Chapter 90).

• Vulvar swelling in a spayed female dog is also associated with estrogenic stimulation and may be a result from the presence of functional ovarian tissue after ovariohysterectomy (ovarian remnant syndrome; see Chapter 90).
• Ovarian remnants are reported more frequently in cats than in dogs, with remnant ovarian tissue more frequently retained at the site of the right ovarian pedicle.


Clinical Signs


The vulvar lips appear edematous and turgid on physical examination. A serosanguineous discharge may be noted.



Diagnosis



• Vaginal cytology: Evidence of estrogenic stimulation. Smears should contain mostly superficial and anuclear squamous cells.

• Hormonal evaluation: Evaluation of serum con-centrations of estradiol and progesterone may be warranted (see Chapter 90).

• Abdominal ultrasound examination: Cystic ovarian tissue, ovarian remnants, and ovarian neoplasia may be evident in the region of the ovaries at the caudal pole of either kidney.



Treatment

Exploratory laparotomy and biopsy: Direct identification, excision, and biopsy of a mass lesion in the region of either or both ovarian pedicles will definitively diagnose the presence of estrogen-secreting ovarian tissue and distinguish among ovarian remnant syndrome, neoplasia, and cystic ovaries (see Chapter 91). Surgical identification of ovarian remnants is easier if the exploratory is performed while the animal is in estrus.



Vulvar Trauma






Etiology.

Injury to the vulva is relatively uncommon but can occur as a result of blunt or penetrating trauma, dog fights, injury during breeding, attempts to disrupt a mating, or difficulty whelping.



Diagnosis



• Evaluation of the injury requires a complete physical examination, digital vulvar and vestibular examination, episiotomy, or vaginoscopy.

• Complete examination of the vulva to determine the extent of the injury may require sedation or general anesthesia when the patient is stable.

• Placement of a urethral catheter and closed urinary collection system may be necessary with severe trauma or swelling of the vulvar or perivulvar region.

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Aug 27, 2016 | Posted by in SMALL ANIMAL | Comments Off on Diseases of the Vagina and Vulva
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