Acute pyelonephritis with renal vein and caudal vena cava thrombosis in a dog (Canis lupus familiaris)

A 4‐year‐old, female, spayed pug was presented with a history of vomiting, restlessness, polyuria and polydipsia. Physical examination revealed a tense abdomen and a temperature of 39.3°C (102.7°F). A complete blood count showed moderate non‐regenerative anaemia and mild neutrophilic leukocytosis with left shift. Biochemistry revealed moderate hypoalbuminaemia and increased blood urea concentration. Plasma C‐reactive protein concentration was also markedly increased. Urinalysis identified pyuria, struvite crystalluria and proteinuria. Abdominal ultrasound imaging identified unilateral hydronephrosis with ureterolithiasis and probable renal vein and caudal vena cava thrombi. Urine culture was negative, but cultures from aspirates of the affected kidney grew Staphylococcus aureus . Computed tomography imaging 24 hours after presentation showed dislodgement of the ureterolith and confirmed the presence of the thrombi. Anticoagulant and antimicrobial drugs were administered, and the dog improved sufficiently to be discharged from the hospital. Antithrombotic and antimicrobial therapy were continued until resolution of the pyelonephritis and thrombosis.