Signalment, history, clinical examination: A male-castrated domestic short hair cat, 5 years old, weighing 4.5 kg presented for acute collapse with no history of trauma. Clinical examination detected pale mucous membranes, prolonged capillary refill time, open-mouth breathing (respiratory rate of 80 breaths per minute), unremarkable thoracic auscultation apart from significant bradycardia (heart rate of 120 beats per minute), weak but synchronous femoral pulses and severe hypothermia (rectal temperature 35.1°C).

Investigations: Serum biochemistry identified azotaemia (creatinine 220 mmol/L; RI 27–180, urea 11 mmol/L; RI 3.6–10.7 mmol/L), increased serum ALT (232 U/L; RI 20–100 U/L), severe hyperglycaemia (21.6 mmol/L; RI 3.9–8.3 mmol/L) and hypoproteinaemia (52 g/L; RI 54–82 g/L). Venous blood gas analysis revealed a moderate metabolic acidosis, respiratory alkalosis and increased lactate concentration (pH 7.309, PvCO2 3.81 kPa, BE(ecf) -12.2, lactate 6.43 mmol/L). Complete blood count detected a non-regenerative anaemia (Hct 19%; RI 24–45%) and moderate thrombocytopaenia (manual count 75x10⁹/L; RI 180–550x10⁹/L). Thoracic ultrasonography was unremarkable. Abdominal ultrasonography revealed a peritoneal effusion and hyperechoic liver. Haemoperitoneum was determined via abdominocentesis (packed cell volume 26%). Hypovolemic haemorrhagic shock was diagnosed. Exploratory laparotomy identified lacerations in the liver as sources of haemorrhage.

Therapy: The left liver lobe was resected and the hilus of the caudate lobe ligated. During surgery, peritoneal blood was auto transfused to the patient and a non-crossmatched type-appropriate whole blood transfusion from a donor cat was administered. After surgery three additional blood transfusions were administered (canine packed red blood cells, non-crossmatched type appropriate cat whole blood, and crossmatched type-appropriate cat whole blood), alongside intensive supportive care. Histopathology identified peliosis hepatis as the cause of the spontaneous haemoperitoneum. The patient survived to discharge and two month followup demonstrated no clinical concerns.

Discussion: This is the first report of successful peliosis hepatis treatment in a cat, and the first case report where autologous, xeno- and allogenic transfusions were administered to the same cat. Based on this case, the authors recommend consideration of peliosis hepatis as a differential diagnosis for spontaneous haemoperitoneum and suggest that survival is possible with aggressive management.