8-year-old Female Spayed English Springer Spaniel

• The urinary bladder wall is diffusely thickened. This thickening extends to the proximal urethra and the lumen of the proximal urethra is mildly dilated. The urine pool is echogenic with a large amount of mobile and gravity dependent debris.
• There are 2 mildly hypoechoic nodules with Doppler flow situated over the ureteral papillae. Both of these nodules and the luminal surface of the urinary bladder between the ureteral papillae and apex are covered with adhered, shadowing material.
• Bilaterally, there is severe dilation of the renal pelvis and blunting of both renal crests.
• The ureters are markedly diffusely dilated. The ureteral walls are thickened and a 2.55 mm peripheral hyperechoic focus is present in the lumen of the left ureter. Both ureters have normal peristalsis (not shown).
• The medial iliac lymph nodes are mildly enlarged bilaterally (not shown).
• The remainder of the examination was unremarkable.

1. Presumptive encrusting cystitis with associated bilateral partial ureteral obstruction, hydroureter, and pyelectasia.

2. The blunted renal crests may be secondary to pressure necrosis or indicate current or historical pyelonephritis.

3. Small left sided ureterolith.

4. The mild dilation of the proximal urethra may indicate a urethral obstruction/partial obstruction of the intrapelvic urethra.

5. Bilateral mild medial iliac lymphadenopathy likely represents reactive lymphoid hyperplasia.

• Encrusting cystitis from Corynebacterium accolens based off culture of the bladder wall crusts obtained via cystoscopy. Bladder biopsy revealed moderate, diffuse, chronic, lymphoplasmacytic cystitis with intraluminal purulent exudate, necrosis, fibrin, mineral, and bacterial cocci.

• CADET BRAF – negative

Discussion of Diagnosis

Encrusting cystitis is a disease process caused by Corynebacterium spp. Patients develop an encrusting struvite and/or calcium phosphate crystalluria that can involve the renal pelvises, ureters, urinary bladder, and/or urethra. Infection with Corynebacterium spp. typically occurs in patients with a history of neoplastic or inflammatory lesions of the urothelium, surgical or endoscopic urinary procedures, or immunosuppression. Often noted in the patient’s history, Corynebacterium spp. is commonly resistant against penicillins and aminoglycosides and, less commonly, fluoroquinolones and tetracyclines. Additionally, it can take up to 72 hours for the organism to grow in culture making diagnosis difficult without previous clinical suspicion. Depending on the severity of mineralization, encrusting cystitis lesions may be visualized on abdominal radiographs, however, CT is optimal for diagnosing calcification of the urinary tract. Ultrasound is useful in identifying encrusting cystitis lesions like urinary bladder wall thickening, encrustation of the urothelium, accumulations of echogenic debris, hydroureter/hydronephrosis, and hyperechoic bands spanning the bladder lumen.

Ultrasound-guided cystoscopy was performed to debride the crusts adhered to the bladder wall. During the procedure, a urinary catheter was placed for amikacin infusion of the bladder. The following day, the patient was diagnosed with subsequent uroabdomen due to ventral perforation of the bladder wall. Emergency surgical lavage of the abdomen was performed where the bladder was also further debrided and bilateral ureteral stents were placed. The uroabdomen resolved about 1 week later, and the patient was sent home on Doxycycline and Clavamox which the bacteria was shown to be susceptible to.

At her recheck appointment 3 weeks later, the lumen of the bladder was significantly improved on ultrasound, and the kidneys and ureters remained similarly dilated. Clumps of white blood cells were seen on urinalysis, so ureteral stent removal was not performed for another 2 weeks.

Antibiotics were continued for an additional 2 weeks following stent removal, and the patient was lost to follow-up.

References

1. Thoumas D, Darmallaicq C, Pfister C, et al. Imaging characteristics of alkaline-encrusted cystitis and pyelitis. AJR Am J Roentgenol 2002;178:389–392.

2. Bailiff NL, Westropp JL, Jang SS, LingGV. Corynebacterium urealyticum urinary tract infection in dogs and cats: 7 cases (1996-2003). J Am Vet Med Assoc 2005; 226:1676-80.

3. Briscoe KA, Barrs VR, Lindsay S, et al. Encrusting cystitis in a cat secondary to Corynebacterium urealyticum infection. J Feline Med Surg 2010;12(12):972-7.