Idiopathic Renal Hematuria

A 7 year old male castrated Boxer presented for evaluation of hematuria. He had a history of chronic otitis, interdigital dermatitis, a I/VI systolic murmur, and periodic episodes of gastrointestinal upset which resolve without any intervention. In 2015, pre-anesthesia CBC and chemistry prior to a sebaceous adenoma removal showed TP 7.7 (5-7.4) and Glob 3.9 (1.6-3.6). His T4 was normal. A urinalysis had a urine specific gravity (USG) of 1.020 with +1 protein, WBC 2-3, RBC 21-50, struvite 11-20, cocci <10, and squamous epithelial cells 2-3. The method of urine sampling was not listed in the medical record. During wellness lab work in November, a CBC, Superchem, T4 and UA were performed. His TP was 7.7 (5-7.4), Glob 4.1 (1.6-3.6), and ALP 149 (5-131) with +2 hemolysis. His T4 was normal. His urinalysis showed a USG of 1.023 with +2 protein, +2 bilirubin, +3 blood, WBC 2-3, and RBC >50. His Accuplex was negative x 4 and fecal O&P showed no ova or parasites and the Giardia ELISA was negative. A urine cystocentesis the following week was very muddy brown. A urine culture showed no growth of bacteria. The patient has no other urinary symptoms other than having brownish urine noticed when it snowed. He did not have any stranguria or pollakiuria. He was active and otherwise healthy at the time of presentation to Hope Veterinary Specialists.

blood_urine

On physical examination, interdigital dermatitis was present. There were no abnormalities noted on examination of the penis or prepuce and his rectal examination was normal. An abdominal ultrasound was normal. Two weeks of empirical enrofloxacin were prescribed in case of pyelonephritis that was not diagnosed on cystocentesis urine culture. A urinalysis was performed at the end of the two week course of therapy while still on the antibiotics. The urine specific gravity was 1.023 with +1 protein, +3 blood, WBC 2-3, RBC >50, squamous epithelial cells 0-1.

Given the history and diagnostics, idiopathic renal hematuria was the top differential but urethral disease or disease within the bladder that was unable to be seen with the ultrasound could not be ruled out. Cystoscopy was performed. The urethral and bladder were normal. Both the left and right ureterovesicular junctions were visualized. Normal urine came was seen jetting from the left. Hematuria was noted from the right. The diagnosis of idiopathic renal hematuria was confirmed.

(Click link below to view cystoscopy video)

Cystoscopy Video

Idiopathic renal hematuria, also called benign essential hematuria and idiopathic renal hemorrhage, is a rare condition in which a patient has gross hematuria from the kidney from unknown cause. It is a diagnosis of exclusion. The condition occurs in both dogs and cats. There are no breed, age, or sex predilections. Many patients will have hematuria as their only symptom but urinary obstruction or other lower urinary signs from blood clots or systemic signs of anemia can also occur.

If the patient’s only clinical symptom is hematuria, as was the case for this patient, no further therapy is necessary. Typically, in these patients, periodic monitoring of the PCV or hematocrit will be performed to monitor for anemia. Historically, nephrectomy was recommended if the disease was unilateral, but this therapy has fallen out of favor since about 30% of patients will eventually develop bilateral disease. For more significantly impacted patients, medical management is recommended as the first tier of therapy. Benazepril can be used to decrease intrarenal pressure. Bazelle and Foale reported on the use of benazepril at 0.22 to 0.53 mg/kg PO q 24 in 4 dogs. Resolution of macroscopic hematuria was observed in all dogs but microscopic hematuria persisted in 2 of the 4 dogs. Anecdotal reports since this 2013 suggest that the overall success rate of benazepril is not as high as was reported in this abstract. Yunnan Baiyou can also be used to decrease bleeding. Allyson Berent, one of the leading experts in this disease, sites a 10-15% success rate with Yunnan Baiyou. If significant bleeding continues despite these therapies, urethroscopy can be performed to find and cauterize the bleeding vessel.

Sclerotherapy is the most successful approach for patients with significant bleeding. In 2013, Di Cicco et al used sclerotherapy with silver nitrate to treat bilateral idiopathic renal hematuria in a dog. The symptoms resolved for 10 months prior to recurrence. Berent et al, 2013 used a povidone iodine mixture followed by a sterile silver nitrate solution administered into the renal pelvis. Complete resolution of macroscopic hematuria occurred in 4 of the 6 patients. The 2 additional patients had moderate improvement of their symptoms. In 2017, Adelman, Barges and Whittemore reported resolution of macroscopic hematuria in 2 dogs within 12 hours of povidone iodine sclerotherapy.

The patient evaluated at Hope was not having significant enough clinical signs to warrant therapy at this time. We will closely monitor him for signs of anemia or lower urinary symptoms secondary to cystic blood clot formation. We plan to recheck his PCV/TS several times a year to monitor him for anemia.

Submitted by: Laurie Prober, VMD, DACVIM

References:

Bazelle J, Foale R. The Successful Treatment of Idiopathic Renal Haemorrhage with Benazepril in Four Dogs. British Small Animal Veterinary Congress 2011. http://www.vin.com/doc/?id=4823393

Berent AC et al. Endoscopic-guided sclerotherapy for renal-sparing treatment of idiopathic renal hematuria in dogs: 6 cases (2010-2012). J Am Vet Med Assoc. 2013;242(11):1556-63. http://avmajournals.avma.org/doi/abs/10.2460/javma.242.11.1556

Adelman LB, Bartges J, Whittemore JC. Povidone iodine sclerotherapy for treatment of idiopathic renal hematuria in two dogs. J Am Vet Med Assoc. 2017;250(2):205-210. http://avmajournals.avma.org/doi/abs/10.2460/javma.250.2.205

Di Cicco MF et al. Management of bilateral idiopathic renal hematuria in a dog with silver nitrate. Can Vet J. 2013;54(8):761-4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3711164/

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