Case Study

Portal vein hypoplasia/microvascular dysplasia in a 1 year old Yorki-poo dog

An 8-month-old Yorkie Poo was presented at an emergency facility for possible UTI as the owner reported the patient was showing inappropriate urinations in the house, pollakuria, and hematuria. Physical examination was within normal limits. The urine was cloudy and yellow in appearance and on urinalysis was alkaline (pH 8.0) with a normal specific gravity, and leukocyturia (4-10) and a moderate amount of triple phosphate crystals were present.

An 8-month-old Yorkie Poo was presented at an emergency facility for possible UTI as the owner reported the patient was showing inappropriate urinations in the house, pollakuria, and hematuria. Physical examination was within normal limits. The urine was cloudy and yellow in appearance and on urinalysis was alkaline (pH 8.0) with a normal specific gravity, and leukocyturia (4-10) and a moderate amount of triple phosphate crystals were present. The patient was treated with antibiotics, to which there was no response and he was presented at the RDVM for persistent hematuria a few weeks later. CBC and blood chemistry were both within normal limits. Urine culture was negative for bacterial growth. The only significant finding on survey abdominal radiographs was bladder stones. Abnormalities on repeat urinalysis a week later were high pH (8.5) 4+ proteinuria, 4+, hematuria, and a large amount of triple phosphate crystals. On a bile acids panel the pre-prandial bile acids were normal but the post-prandial bile acids were elevated (post 70 mg/dl) Pending results the patient was placed on the L/D diet.

DX

Portal vein hypoplasia/microvascular dysplasia

Sonographic Differential Diagnosis

Urinary pathology- Cystic calculi and concurrent cystitis. Potential for concurrent urinary tract infection. Liver pathology – Portal vein branch hypoplasia/microvascular dysplasia likely. Non-shunt causes of bile acid elevation also possible such as intestinal dysbiosis or idiopathic transient elevation (See comments below)

Image Interpretation

Image 1: Two separate shadowing cystic calculi are present with minor bladder wall thickening in the near field. Image 2: Normal kidney with no significant evidence of mineralization. Image 3: The gall bladder demonstrates normal size and contour. However, the diaphragm takes a sharper angle toward the right of the screen likely indicating subnormal liver size. Image 4: Deep right liver demonstrating mildly coarse parenchyma and normal gastric content to the right. Image 5: Right intercostal approach to the liver further demonstrates the coarse and mildly heterogenic parenchyma primarily in the far field. Image 6: Right caudal liver demonstrating isoechoic of this portion of the liver when compared to the right kidney. Image 7: Transverse view of the liver compared to the normal spleen. Both organs are isoechoic to each other, which is considered normal. Image 8: Split portal hilus view demonstrating the portal vein (pv)/vena cava (cvc) ratio on the left and normal portal vein and branches on the right. The 1/1 ratio and normal branching of the portal vein rules out the presence of extrahepatic porto-systemic shunt (i.e. splenocaval, gastrocaval, splenoazygos, gastroazygos shunts). Image 9: Right intercostal view of the deep vena cava (bottom) and hepatic vein (blue) and artery (red) indicating normal perfusion even thought the liver is subnormal in size. The normal flow and CVC size as well as the normal curvilinear contour of the vasculature rules out the presence of macroscopic intrahepatic shunting.

Outcome

The patient was placed on a medical protocol for microvascular dysplasia, which resulted in resolution of the urinary tract signs.

Comments

No video is available on this patient.

Clinical Differential Diagnosis

Portocaval shunt, microvascular dysplasia, bladder calculi

UA PH

8.0

UA PH

8.0

Sampling

Surgical liver biopsies were performed which showed arteriolar hyperplasia, portal vein hypoplasia/microvascular dysplasia. Analysis of the bladder calculi (obtained via cystotomy) revealed ammonium biurate calculi.