Frontal septation of the bladder in a mare.

The article presents a case study of a 17-year-old mare that had persistent bladder infections due to abnormal urinary tract anatomy characterized by a septum in the bladder, dilated ureters, and displaced kidneys. Despite antibiotic treatment, the mare’s infections did not resolve, leading to euthanasia. During the autopsy, it was found that there was considerable distortion in the urinary tract, likely explaining the persisting infections.

Background and Presentation

• The horse presented with a chief complaint of bladder infection, displaying symptoms such as infrequent urination, vulvar discharge, and distended ureters noticed during examination.
• Urinalysis revealed septic cystitis with two kinds of bacteria in the urine: Streptococcus zooepidemicus and Enterococcus sp.
• Despite antibiotic treatment based on susceptibility patterns, the mare’s condition did not improve fully.
• During examination, abnormalities such as an enlarged urethral papilla and distally distended ureters were identified, hinting at abnormal anatomy.

Investigations

• Transrectal and transabdominal ultrasonography showed an abnormal fluid-filled structure and displaced kidneys.
• Video-uroscopy revealed an unusually small bladder, dilated ureters with a “golf-hole” appearance at their orifices, indicating intermittent retrograde flow of urine, hence the suspect of abnormal anatomy was confirmed.
• Mucosal surfaces displayed signs of inflammation, and a purulent exudate mixed with calcium carbonate crystals was found.
• Laparoscopy showed dilated ureters.

Treatment and Outcome

• Treatment with gentamicin was initially administered for 10 days. Despite this, prognosis for resolution of infection was poor given the extensive abnormalities found in the urinary tract.
• Three months later, the mare was again admitted with persistent infection; with the owner deciding euthanasia due to a decline in the quality of life for the mare.
• Post-mortem examination of the horse revealed chronic bilateral hydroureter, retained fetal lobulation with chronic infarction of the right kidney, and a fibromuscular septum separating the urinary bladder.

Conclusion

• The article concludes by defining cystitis and citing it as a common issue in both humans and horses due to anatomical variances.
• In cases of persistent infection like this, it implies that there may be some form of abnormality within the urinary tract which may lead to bacterial colonization, in this case, the abnormal anatomy the mare had.