Equine idiopathic hemorrhagic cystitis: Clinical features and comparison with bladder neoplasia

• Published in: Journal of veterinary internal medicine Vol. 32; no. 3; pp. 1202 - 1209
• Main Authors: Smith, Fauna L., Magdesian, K. Gary, Michel, Adam O., Vaughan, Betsy, Reilly, Christopher M.
• Format: Journal Article
• Language: English
• Published: United States John Wiley and Sons Inc 01-05-2018
• Subjects: Animals; bladder neoplasia; Cystitis - diagnosis; Cystitis - pathology; Cystitis - veterinary; cystoscopy; Diagnosis, Differential; EQUID; Female; hematuria; Hematuria - diagnosis; Hematuria - pathology; Hematuria - veterinary; Horse Diseases - diagnosis; Horse Diseases - pathology; Horses; Male; Retrospective Studies; Urinary Bladder - pathology; Urinary Bladder Neoplasms - diagnosis; Urinary Bladder Neoplasms - pathology; Urinary Bladder Neoplasms - veterinary; hematuria; cystoscopy; bladder neoplasia
• ISSN: 0891-6640; 1939-1676
• DOI: 10.1111/jvim.15121

Background
A new syndrome of hematuria in horses has been documented.
Hypothesis/Objectives
Hemorrhagic cystitis is a novel cause of stranguria and hematuria in horses. This syndrome may be difficult to differentiate from bladder neoplasia because they share several clinical features.
Animals
Eleven horses with idiopathic hemorrhagic cystitis and 7 horses with bladder neoplasia.
Methods
Retrospective cohort study.
Results
Hemorrhagic cystitis was detected on cystoscopy of affected horses, with hemorrhagic and thickened apical bladder mucosa. Clinical signs and endoscopic appearance of the bladder resolved within 3‐8 weeks. Histopathology of bladder mucosal biopsy specimens featured neutrophilic and hemorrhagic cystitis. Histopathology was suggestive of dysplasia or neoplasia in 3 horses with hemorrhagic cystitis, yet the horses experienced complete resolution, suggesting that small biopsy specimens obtained by endoscopy can be difficult to interpret. Horses with bladder neoplasia had lower hematocrits, were older, more likely to be female, and more likely to have a mass detected on ultrasonographic examination of the bladder than horses with hemorrhagic cystitis syndrome.
Conclusions and Clinical Importance
Hemorrhagic cystitis represents a novel differential diagnosis for horses with hematuria, and is associated with a favorable prognosis. Although histopathology may suggest a neoplastic process, affected horses should be monitored cystoscopically, because complete resolution of hemorrhagic cystitis occurs. The cause of this disease is unknown, and warrants investigation.