Case Study

Cystic calculi in a 5 year old FS DSH cat

A 5-year-old female spayed DSH cat was presented for evaluation of difficulty urinating for the past 8 months

Sonographic Differential Diagnosis

Bladder calculi. Minor renal calculi, non obstructive at this time. Mild to moderate degenerative renal changes. Interstitial nephrosis pattern. Recommend cystotomy and stone analysis in this patient; bladder wall biopsy and culture is also indicated to ensure underlying interstitial cystitis is not present.

Image Interpretation

Numerous, variably sized, shadowing small calculi. The urinary bladder has a regionally thickened wall, primarily at the apex of the ventral wall. The kidneys presented minor, degenerative changes. They were normal in size, but there were areas of mineralization in the medulla and corticomedullary junction. The left kidney measured 4.06 cm. The right kidney measured 4.19 cm with minor mineralization.

DX

Cystic calculi: 100% ammonium acid urate.

Clinical Differential Diagnosis

Bladder pathology – interstitial cystitis, chronic bacterial cystitis, uroliths, neoplasia. Urethral pathology – stricture, urethritis, neoplasia, calculi.

Sampling

The patient was taken to surgery for a cystotomy. The interior layer and exterior layer of the stone(s) evaluated both revealed 100% of ammonium acid urate.