Clinical Exposures: Incidental finding of renal agenesis in a cat

Clinical Exposures: Incidental finding of renal agenesis in a cat

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Jun 01, 2010


Figure 1. A ventrodorsal urogram obtained five minutes after intravenous injection of an iodinated positive contrast medium in a 2-year-old cat. Note the well-defined right kidney and ureter and the absence of the left kidney.
An approximately 2-year-old feral female domestic shorthaired cat weighing 6.1 lb (2.8 kg) was presented to a spay and neuter clinic for a routine ovariohysterectomy. The cat was fractious and bright, alert, and responsive. The physical examination findings were unremarkable, but cytologic examination of an ear swab sample revealed a mite infestation (Otodectes cynotis). The results of a rapid ELISA test for feline heartworm, feline leukemia virus, and feline immunodeficiency virus were negative.

OVARIOHYSTERECTOMY

Anesthesia was induced with xylazine and ketamine given intramuscularly. The cat was intubated, and anesthesia was maintained with isoflurane in oxygen. Perioperatively, 125 ml of lactated Ringer's solution was administered subcutaneously as a bolus to maintain hydration. Intraoperatively, the cat's heart rate and rhythm, respiration, and temperature were monitored manually. Electrocardiography and pulse oximetry were also used to monitor the patient.

A ventral midline celiotomy was performed. Exteriorizing the uterus revealed only one completely developed right ovary and a normally developed right uterine horn with good vascularity leading to a normal cervix. The contralateral uterine horn was absent. A thorough abdominal exploration revealed that the left ovary was embedded and masked in anterior abdominal fat caudal to the spleen; the ovary had auxiliary blood vessels from adjoining fatty tissues. Both ovaries were fully developed and had the same size and shape. Further exploration revealed the absence of a left kidney. Visualization of the abdominal organs was unremarkable. An ovariohysterectomy was performed. The abdominal incision site was closed in a routine manner with 3-0 polydioxanone suture.

Recovery was uneventful. Postoperatively, analgesia was maintained by buprenorphine (0.02 mg/kg intramuscularly). A postoperative survey radiographic examination confirmed no other thoracic, abdominal, or pelvic organ defects.

RECOVERY

The following day, the cat was bright, alert, and responsive and had a good appetite. Its temperature, pulse, and respiratory rate were normal. A complete blood count and serum chemistry profile revealed leukocytosis (total WBC = 28.91 x 103 /µl; reference range = 5.5 to 19.5 x 103 /µl), hyperglycemia (glucose concentration = 180 mg/dl; reference range = 70 to 150 mg/dl), hypoalbuminemia (albumin concentration = 1.8 g/dl; reference range = 2.2 to 4.4 g/dl), hyponatremia (sodium concentration = 139 mEq/L; reference range = 142 to 164 mEq/L), and a decreased total protein concentration (4.9 g/dl; reference range = 5.4 to 8.2 g/dl). These abnormalities were attributed to postsurgical stress.

IMAGING

To confirm the anatomical structure and assess the qualitative function of the existing kidney, an intravenous excretory urographic examination was performed the next day. A radiograph was obtained five minutes after intravenous injection of an iodinated positive contrast agent. The left kidney, ureter, and renal artery were not visualized; the right kidney and ureter were normal in size and shape (Figure 1). Most of the contrast agent was excreted into the urinary bladder within 15 minutes, which confirmed normal renal architecture and effective glomerular filtration.

On an ultrasonographic examination performed four days after surgery, the right kidney was normal in size (4.35 cm long and 2.43 cm wide) and had a regular echo texture and renal pelvis. The bladder was full and had hypoechoic urine. The mucosal and muscular layers and trigonal areas appeared normal. The liver, stomach, intestines, mesenteric lymph nodes, pancreas, adrenal glands, and spleen appeared normal.

Histologic examination of the reproductive organs removed during the ovariohysterectomy was not conducted, although it is prudent to examine these tissues histologically to help describe the type of anomaly in these animals.

FOLLOW-UP

The cat was discharged to a foster home six days after surgery. The ear mite infestation was treated with 0.01% ivermectin otic suspension. The cat was eventually adopted, and its health has been periodically monitored. In a recent biannual check-up, complete blood count and serum chemistry profile results revealed no abnormalities.