Julia Lankton, Natalie Durrett Crawford, Ondrej Becvar, Tanya LeRoith Virginia-Maryland Regional College of Veterinary Medicine Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Three week old Holstein heifer calf from large dairy  Abdominal distension Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Ataxia  Thiamine  Diarrhea  Sulfamethazine  Florfenicol  Electrolytes  Poor muscle tone Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Good appetite with little weight gain  Chemistry panel: Low BUN  EMG: WNL  Continued/Worsening ataxia  Rx corticosteroids – no improvement  Euthanized at 6 weeks Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Bacterial  TEME  Vertebral osteomyelitis  Viral  Rabies  Pseudorabies  Parasitic  Nervous coccidiosis  Parelaphostrongylus tenuis  Nutritional  Polioencephalomalacia  Vitamin A deficiency  Toxic  Lead toxicosis  Urea toxicosis  Congenital  Hydranencephaly  Hydrocephalus  Porto-systemic shunt?  Nah, that’s in small animals Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Body weight: 68 kg (150 lbs)  Normal: 82 kg (180 lbs)  Minimal fat stores  Small liver  Cerebral cyst Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Lobules small and irregular  Lymphatics and sinusoids dilated  Portal regions:  Small portal veins  Numerous portal arterioles Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Liver H&E Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Liver H&E Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Liver H&E Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 White matter vacuolization  Pronounced in white matter tracts bordering grey matter  Severity increases caudally  Scattered neuronal necrosis  1.4 mm diameter ependymal lined space  Rostral cerebral white matter Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Cerebrum H&E Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Cerebrum LFB-PAS Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Brainstem H&E Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Brainstem LFB-PAS Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Spinal Cord H&E Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Cerebrum H&E Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Morphologic :  Liver : arteriolar reduplication, lobular atrophy and lymphatic dilation  Brain : white matter, polymicrocavitation; focal syringoencephalocele  Disease : Portosystemic shunt with hepatic encephalopathy Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Rare in large animals (4 cases in calves)  Normal fetal communications patent  Portal blood bypasses liver and enters circulation  Decreased portal vein perfusion  Liver lobules atrophy  Portal veins are hypoplastic  Hepatic arterioles are hyperplastic Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Toxins from portal blood access CNS  Ammonia  astrocytes  decreased BBB  Ammonia, fatty acids, amino acids and other neurotoxins enter CNS  Astrocyte hypertrophy and degeneration  Alzheimer type II cells  More prominent in other spp.  Intramyelinic Edema  Diffuse bilaterally symmetrical polymicrocavitaton, predominantly of white matter and at grey-white border Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 Dr. Natalie Durrett Crawford  Dr. Tanya LeRoith  Dr. Ondrej Becvar  Dr. Bernard Jortner  VMRCVM histopathology lab Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

 1.Buczinski, Sebastien, et. al. Portacaval shunt in a calf: Clinical, pathologic, and ultrasonographic findings. Can Vet J 2007; 48:  2. Van Den Ingh, et. al. Congenital portosystemic shunts in three pigs and one calf. Vet Pathol 1990; 27:  3. Reimer JM, et. al. Diagnosis and surgical correction of a patent ductus venosus in a calf. JAVMA 1988; 193: Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only