Severe anemia in cats with urethral obstruction: 17 cases (2002-2011)

ObjectiveTo characterize clinical parameters of cats with severe anemia due to suspected urinary bladder hemorrhage associated with urethral obstruction. DesignRetrospective case-control study. SettingUniversity teaching hospital. AnimalsSeventeen cats with urethral obstruction and severe anemia (group UO-A) that required transfusion were identified via medical record database search. Thirty cats with urethral obstruction and mild or no anemia (group UO) were included as controls. InterventionsNone. Measurements and Main ResultsThe median PCV of all cases at presentation was 28% (range, 9%-47%). Seven cats had PCV 20% at presentation, and all transfused cats had PCV 20% at the time of transfusion. Three cats did not receive a transfusion despite PCV 18%. Cats in the UO-A group had a significantly longer duration of clinical signs (P = 0.001), and were more likely to have a history of previous urethral obstruction (P = 0.011), have a heart murmur (P = 0.002), have a gallop rhythm (P = 0.005), and have lower blood pressure (P = 0.007) compared to those in the UO group. Additionally, UO-A cats had significantly lower pH, more negative base excess, higher BUN, and higher creatinine compared to UO cats. Duration of urinary catheterization was significantly (P = 0.016) longer in UO-A cats. All UO cats survived to discharge, whereas 4/17 (23.5%) UO-A cats were euthanized (P = 0.013). ConclusionsA history of previous urethral obstruction and longer duration of clinical signs may be important risk factors for severe anemia in UO cats. Additionally, UO-A cats appeared to be more severely affected, as evidenced by lower blood pressure, more severe metabolic acidosis, higher BUN and creatinine, and worse outcome.