Diagnosing urinary tract disease in adult horses. Part 1: abnormalities in the passage of urine

Abnormalities in the passage of urine can occur in adult horses because of disorders of the urinary tract itself or diseases in other body systems, including neurological, musculoskeletal and gastrointestinal. Stranguria, pollakiuria and polyuria can be difficult to differentiate from each other in the clinical setting; careful history taking and observation of the horse is essential. Stranguria is most commonly caused by cystoliths, and has a good prognosis with surgical removal. Bacterial cystitis is the main cause of pollakiuria; this is rarely a primary condition so predisposing causes should be investigated. Psychogenic polydipsia is the most common cause of polyuria in horses without pituitary pars intermedia dysfunction but should be differentiated from renal disease and diabetes insipidus. Urinary incontinence should prompt a full neurological examination and typically carries a poor prognosis.