Evaluation of chromocystoscopy in the diagnosis of cystitis in female donkeys

Abstract

Early detection of cystitis in equine is essential to improve the prognosis and outcome of therapy. However, the conventional white light endoscopy is not sufficiently accurate for this purpose. Hence, this study evaluated chromoendoscopy as a recent diagnostic tool for cystitis in female donkeys. For this purpose, 5 apparently normal donkeys (control group) and 5 female donkeys with cystitis (diseased group) were used. Physical and rectal examinations, urine analysis, white light cystoscopy, methylene blue-based chromoendoscopy and histopathology were performed in all animals. Turbid urine exhibiting an alkaline pH and a significant (P = .02) increase in the numbers of RBCs and WBCs was observed in the diseased group compared to the control one. In the control group, white light cystoscopy showed a smooth pale pink glistening mucosa with two openings of the ureters and visible submucosal blood vessels. During chromocystoscopy, faint bluish discoloration of the mucosal surface with clearly visible submucosal blood vessels was detectable. These findings were correlated with the histopathological findings of the biopsies collected from the urinary bladder. In the diseased group, white-light cystoscopy showed clearly visible blood vessels, mildly hyperaemic mucosa in focal or diffuse forms and small vesicle formation. Chromocystoscopy revealed dark bluish oedematous and irregular mucosa either in a focal form or a diffuse form (marbled appearance) with deeply stained submucosal blood vessels. Histopathologically, the urothelium was hyperplastic with squamous metaplasia and the lamina propria was infiltrated with few leukocytes and congested blood vessels. Small bluish dots representing the absorbed methylene blue dye were seen in the inflamed areas against the lightly stained mucosa of the bladder. Severe diffuse necrotic cystitis was also seen with bacterial aggregations on the surface. Gram's staining revealed both gram positive bacilli and Gram positive coccobacilli. In conclusion, chromoendoscopy is a helpful tool for early diagnosis of cystitis in female donkeys and enables targeted biopsies, which improves the prognosis and outcome of therapy.

Fig 1

(a) Plain cystoscopy in a normal female donkey showing 2 ureteral orifices (black arrows) on the dorsal surface of the urinary bladder at 11 and 1 o’clock and pale pink mucosa with observed small blood vessels. (b) Plain cystoscopy in a normal female donkey showing a glistening smooth mucosal surface and visible submucosal blood vessels. (c) Acetic acid cystoscopy in a normal female donkey showing hyper-whitening of the mucosal surface. (d) Chromocystoscopy in a normal female donkey showing faintly discoloured mucosal surface and visible submucosal blood vessels. (e) Chromocystoscopy in a normal female donkey showing ureteral orifices with a urine stream at 1 o’clock (black arrow), normal faintly discolored mucosal surface and clearly visible submucosal blood vessels. (f) Normal histological structure of the urinary bladder in a female donkey showing intact transitional epithelium (H and E stain X 200).

Fig 2

(a) Plain cystoscopy in a female donkey with cystitis showing slight hyperemic mucosa and clear submucosal blood vessels at the apex vesicae. (b) Acetic acid cystoscopy in a female donkey with cystitis showing mucosal irregularities at the apex vesicae (c) Chromocystoscopy in a female donkey with cystitis showing diffuse dark bluish discolored and edematous mucosa. (d) Chromocystoscopy in a female donkey with cystitis showing diffuse dark bluish inflamed mucosa with marbled appearance. (e&f) Chromocystoscopy in a female donkey with cystitis showing small focal dark bluish inflamed mucosal areas (arrows).

Fig 3

(a) Acetic acid cystoscopy in a female donkey with cystitis showing large focal edematous mucosal areas (arrows). (b) Chromocystoscopy in a female donkey with cystitis showing large deeply stained, raised mucosal areas (arrows).

Fig 4

Biopsies from the urinary bladder of female donkeys with cystitis showing: (a) Focal hyperplasia of the urothelium with a few leukocytic infiltrates in the lamina propria and submucosa (Hematoxylin and eosin,×200). (b) Focal areas of erosions (long arrows) and squamous metaplasia in the urothelium (short arrow), accompanied with congested blood vessels and inflammatory cell infiltration (Hematoxylin and eosin, x200). (c) Necrosis of the the urothelium, diffuse leukocytic infiltration in the submucosa and bacterial aggregations on the surface (Hematoxylin and eosin,×100). (d) Gram-negative bacilli (long arrow) are observed on the mucosa, and Gram-positive coccobacilli (short arrow) are observed in necrosed tissue (Gram’s stain ×1000).