Methods for Diagnosing Diseases of the Female Reproductive Tract

Chapter 205


Methods for Diagnosing Diseases of the Female Reproductive Tract




Vaginoscopy



Clinical Uses


In the bitch, vaginoscopy is a valuable tool to evaluate reproductive anomalies and presence and severity of trauma, to determine the source of vulvar discharge, and to detect reproductive related causes of urinary incontinence and recurrent urinary tract infection (Lulich, 2006). In the normal estrous bitch, vaginoscopy can be used to stage the cycle when timing artificial insemination along with vaginal cytology and endocrine testing. During proestrus, the vaginal mucosal folds are edematous, moist, and pink. During estrus, the vaginal folds appear wavy with an almost serrated appearance (crenulated).



Technique



Preparation


Vaginoscopy can be performed with a vaginal speculum, otoscope, or pediatric proctoscope, but the lack of distention of the vaginal lumen can limit access to the cranial vagina. Endoscopic vaginoscopy can provide for better evaluation of the cranial vagina and cervix. This can be performed with a flexible or rigid endoscope or a cystoscope.


During the estrus phase most bitches allow for evaluation without sedation. In the anestrus animal or evaluation for a pathologic process, it is beneficial to use sedation or general anesthesia and perform the exam with the animal in dorsal recumbency.


Perivulvar hair should be clipped and the tail wrapped in long-haired dogs. The perivulvar region and perineum should be cleaned thoroughly with povidone-iodine or mild soap and water to minimize contamination. A lubricating agent is applied on the sides of the endoscope to pass it through the vulvar folds and into the vestibule with caution not to apply lubricant to the tip of the scope, which would obstruct the view.



Procedure


Initially the scope is passed with the tip acutely angled toward the spine of the dog to avoid the clitoris and clitoral fossa. Once inside, the vestibule can be distended with air or sterile, warm, isotonic fluid through a port on the scope. To prevent loss of fluid during vaginal distention, the thumb and first finger are used to lightly occlude the vulvar commissure around the tip of the scope. Room air can be used to insufflate the vaginal vault and vestibule. A vaginal cannula with an inflatable cuff could aid greatly in maintaining distention of the vaginal walls. A complete seal is not necessary and difficult to maintain; therefore a steady stream of fluid or air helps to maintain distention of the vaginal lumen. Insufflation with air is the best choice for sample collection for cytology or cultures, whereas distention with fluids could be useful to evaluate for structural and anatomic integrity of the different structures.


The vestibule should be examined when the scope is just past the vulvar commissure. Common lesions that may be found in the vestibule are anatomic and congenital anomalies, areas of hyperemia, lacerations, presence of discharge or blood, and foreign bodies. However, other than foreign material and mucosal pathologies, pathologies rarely are found in the vestibule. In some cases of urinary incontinence a vaginal termination of ectopic ureter can be identified. Next the vestibulovaginal junction and urethral os should be identified. This junction should be smooth and continuous with a symmetric opening. Asymmetry can be an indication of pathology. The vestibulovaginal opening should be dorsal to and wider than the urethral opening. A smaller or narrower vestibulovaginal opening should be considered a stricture. If the junction is divided into two or more openings, a diagnosis of vaginal septa or vaginal duplication may be made.


After the vestibule is evaluated, the scope is passed through the vestibulovaginal junction into the vagina. If discharge is present, the clinician should try to identify its origin. The wall of the vagina should be examined thoroughly for lesions and pathologies by rotating or changing the angle of the scope. The same technique should be used to evaluate the cranial vagina and the external cervical os. Care must be taken not to touch the vaginal fornix in the awake animal because this can be a sensitive area and pressure often results in discomfort.


Samples or biopsy may be obtained by several methods if any pathology is identified. A long 22- or 25-gauge needle can be passed through the biopsy channel of the scope to obtain fine-needle aspirates. Small biopsy forceps can be directed through the biopsy channel as well to collect a larger sample (Gunzel-Apel et al, 2001).



Vaginal Cytology



Clinical Uses


Vaginal cytology is a simple, quick, and economical tool commonly used to monitor hormonal influence on the canine vaginal epithelium. Vaginal cytology is most valuable as an estrogen bioassay in the bitch and queen. Vaginal cytology also can be used to identify an inflammatory pathology in the female reproductive tract (e.g., vaginitis, pyometra).


During the stages of anestrus, proestrus, and diestrus, the predominant cell type found on vaginal cytology is the round parabasal cell. Red blood cells, neutrophils, and bacteria also may be seen in low numbers. As proestrus progresses, the follicles produce more estradiol. In response to increased estradiol concentrations, there is hyperplasia of the vaginal epithelium. As the thickness of the vaginal epithelium increases, superficial cells move farther away from the blood supply of the basement membrane. These cells become nonviable anuclear cells. The highest number of these cornified superficial epithelial cells is found during estrus. A vaginal cytology sample taken during estrus should contain more than 80% cornified superficial epithelial cells. Red blood cells can be found in low numbers and neutrophils should not be present. At the onset of diestrus (6 to 7 days after ovulation in the bitch), vaginal cytology changes quickly from full cornification to 40% to 60% parabasal and intermediate cells. At this time neutrophils, parabasal cells with a neutrophils in the cytoplasm (metestrum cells), and parabasal cells with vacuoles in the cytoplasm (foam cells) may be seen.



Technique


The technique for obtaining vaginal cytology specimens is simple. The clinician’s fingers can be used to open the vulvar folds, applying gentle traction caudally with the index and middle finger at the cranial aspect of the base of the vulva while applying gentle caudal ventral traction with the thumb at the ventral commissure of the vulva. A long cotton-tipped applicator (premoistened with saline to prevent friction) can be introduced through the vulva and vestibule into the vagina. When introducing the swab, the clinician should avoid picking up keratinized cells from the clitoral fossa on the ventral surface because these can be confused with superficial vaginal epithelial cells. The swab is passed dorsally and cranially to avoid the urethral papilla located ventrally caudal to the vestibule-vaginal junction. After the ischial arch is reached, the swab should be leveled and advanced cranially. The swab is rotated within the vagina a few times and then withdrawn. The swab is rolled onto a microscope slide in two to three nonoverlapping rows. After the smear is prepared, the slide is air dried and stained with a modified Wright-Giemsa stain (Diff-Quik). The stained slides should be evaluated at 40× magnification under the microscope.

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Jul 18, 2016 | Posted by in PHARMACOLOGY, TOXICOLOGY & THERAPEUTICS | Comments Off on Methods for Diagnosing Diseases of the Female Reproductive Tract

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