Adam Shoelson, Mary Labato
History: An 11-week old female Golden Retriever presented for vomiting, azotemia, and elevated liver enzymes. The puppy’s owners had not visualized any urinations in the three days prior to presentation. She was obtained from a breeder in Virginia and had received one DHPP vaccine and a round of deworming. Can you Solve the Case of the Month?
On presentation to Foster Hospital for Small Animals, the dog was quiet and 5-7% dehydrated. AFAST demonstrated a small volume of peri-renal free fluid and an empty urinary bladder. Blood work revealed azotemia (BUN 104mg/dl, creatinine 4.3mg/dl), hyperkalemia (5.8mEq/L) and hyperbilirubinemia (3.0mg/dl). The dog had a mild neutrophilia (12.857K/ul) and mild thrombocytopenia (194K/ul).
Determine which additional diagnostics are required.
A Leptospirosis antibody panel by microscopic agglutination was submitted to Idexx Reference Laboratory and was negative. A baseline cortisol was elevated (27.7ug/dl). Abdominal ultrasound revealed hypoechoic hepatomegaly, hyperechoic kidneys with peri-renal effusion, and peritoneal effusion.
Formulate a treatment plan.
The patient was administered a 250ml bolus of 0.9% NaCl to correct her hydration deficit. Half-strength saline was run at a low rate of 10ml/hr. (35ml/kg/day) due to concern for anuria. 2.5% dextrose was added to the fluids to treat the puppy’s hyperkalemia. She was started on ampicillin (22mg/kg IV q8 hr). Over the first 12 hours of hospitalization, no urine production was noted. There was progressive azotemia (BUN 174mg/dl, creatinine 6.7mg/dl) and hyperkalemia (7.8mEq/L). Clinically the patient was declining. She became weak and dull and began to develop early signs of over-hydration (chemosis, serous nasal discharge).
What is the appropriate next step for this patient?
Dialysis was recommended due to the patient’s anuria, progressive azotemia, life-threatening hyperkalemia, and over-hydration. Intermittent hemodialysis (IHD) was initiated to facilitate the removal of uremic toxins. Ultrafiltration was prescribed during early sessions to remove excess fluid. Each of the three prescribed sessions was four hours in length, with urea reduction ratios from 40% to 80%. Inter-dialytic management included a furosemide CRI (1 mg/kg/hr), ampicillin (22 mg/kg IV with frequency reduction to q12 hr), LRS at 8 ml/hr (to account for insensible losses), amlodipine, and maropitant. An esophagostomy tube was placed during dialysis catheter placement but was not needed due to the dog’s persistently healthy appetite.
Profound polyuria followed the third dialysis session, an indication that the dog had begun a recovery phase of the AKI. With the development of polyuria, urine output and intravenous fluid rates were matched. The maximum fluid rate administered was 350 ml/hr (1,292 ml/kg/day). This was slowly tapered back to maintenance. During this time, the azotemia resolved (BUN 24, creatinine 1.1)). Convalescent Leptospirosis titers demonstrated seroconversion. The puppy was discharged after two weeks in the hospital with just doxycycline. She is clinically normal at home, and her kidney values remain within normal limits.
Comments from Tufts Internal Medicine Team
Consider consultation with Foster Hospital’s Dialysis team if you believe you have a patient that meets the criteria for dialysis. Early initiation of dialysis, can improve outcome with AKI. The authors consider the Leptospirosis vaccine as a core vaccine. It should be administered to all dogs, even those who may be low risk. Leptospirosis can be a devastating disease, but owners should also be advised that the prognosis with Leptospirosis-induced AKI is fair (approximately 75% survival rate), and should be encouraged to treat.