A rare case of vulvar discharge associated with exogenous oestrogen exposure in a spayed Weimaraner bitch.

OBJECTIVE: This report documents a rare case of vulvar discharge associated with exogenous oestrogen exposure in a large-breed dog. CASE DESCRIPTION: A 4-year-old spayed Weimaraner bitch was presented for evaluation of inappetence and intermittent sanguineous vulvar discharge. Physical examination, vaginal cytology, haematological, and ultrasonographic findings were indicative of a uterine stump pyometra. A celiotomy was performed, and the uterine stump appeared grossly cystic and thickened. Histopathological evaluation of the removed uterine stump and ovarian pedicles revealed cystic endometrial hyperplasia and no ovarian tissue. Fifteen days after surgery, the patient presented again with a sanguineous vulvar discharge. Vaginal cytology revealed predominantly superficial cells, indicating oestrogen influence. Further questioning of the owner revealed the long-term use of a topical oestrogen cream by a member of the household. Serial examinations were performed, and the cytology remained uniform, with predominantly superficial cells, indicating continued oestrogen influence. Progesterone and anti-Müllerian hormone tests were negative, which made the presence of ectopic ovarian tissue unlikely. These results coupled with the history of topical oestrogen cream use in the household suggested that the patient's clinical signs were most likely due to exogenous oestrogen exposure. After the owner implemented various recommendations made to prevent the exposure, the clinical signs resolved completely. CONCLUSIONS: This case demonstrates that although rare, exogenous oestrogen exposure can be a cause of vulvar discharge in a large-breed spayed bitch. Therefore, regardless of the breed, exogenous oestrogen exposure must be included in the list of differential diagnoses for all clinical presentations associated with oestrogenic influence in dogs.

Development and validation of an ultra performance liquid chromatography tandem mass method for sildenafil and N-desmethyl sildenafil plasma determination and quantification.

Sildenafil is a selective inhibitor of cGMP-specific type 5 phosphodiesterase (PDE5) used for the treatment of masculine erectile dysfunction and Pulmonary Arterial Hypertension (PAH). Sildenafil causes vasodilatation; relax of the smooth muscle and reduction of pulmonary arterial pressure. In the liver cytocrome P450 metabolizes sildenafil into its active metabolite, N-desmethyl sildenafil. The determination of plasma levels of sildenafil and N-desmethyl sildenafil could be useful for therapy optimization and pharmacokinetic studies. We have developed and validated a new method for the quantification of sildenafil and its metabolite in human plasma by rapid protein precipitation extraction, using an UPLC system, coupled with a tandem mass spectrometric detector (UPLC-MS/MS). The calibration range was fitted at least square model (r(2)≥0.999), with an accuracy and an intra- and inter-day RSD% (Relative Standard Deviation), both for sildenafil and N-desmethyl sildenafil, lower than 15%, as required by the FDA guidelines; LLOQ, LLOD, ULOQ were 3.9ng/mL, 1.95ng/mL and 1000ng/mL, respectively, for both analytes. Matrix effect, expressed as mean percent deviation of peak areas, was in the range between 2.6% and 5.8%, lower than 15% as required by guidelines. The mean recovery was 83.2 % for sildenafil and 84.5% for N-desmethyl sildenafil. This method has successfully been applied to a clinical pharmacokinetic study of sildenafil and N-desmethyl sildenafil in patients with PAH undergoing cardiac surgery.