Congenital feline portosystemic shunts

Five young cats with portosystemic communications, 2 with single intrahepatic and 3 with single extrahepatic portosystemic communications, were managed surgically. One cat with a ductus venosus was treated successfully by surgery. Ptyalism and behavioral changes were similar in all 5 cats. Biochemical abnormalities included low BUN values, increased blood ammonia values, and increased sulfobromophthalein retention. None of the cats had portal hypertension at the time of surgery. Seemingly, single portosystemic shunts should be considered a surgical disease in the cat.     

Congenital portosystemic shunts in dogs: 46 cases (1979-1986)

Congenital portosystemic shunts (CPSS) were diagnosed in 46 dogs. The historic, physical, and laboratory findings were tabulated. Half of the affected males were cryptorchid. Urolithiasis was detected in 20% of the dogs. The biochemical tests with the best sensitivity for the diagnosis of CPSS were sulfobromophthalein retention, fasting serum ammonia concentration, and serum alkaline phosphatase activity. The survival time and quality of life were assessed by physical and biochemical reevaluation of the dogs and by means of a questionnaire that was completed by the owners. Five dogs were treated medically. Thirty-three dogs were treated surgically. Dogs that had complete surgical occlusion of the CPSS became normal, and quality of life was excellent. Dogs that had partial occlusion of the CPSS improved, and some became clinically normal. Dogs that did not have surgical correction of the CPSS had continuation of signs, but several survived for years.     

Congenital portosystemic shunts in dogs and cats

Congenital portosystemic shunts (PPS) are abnormal vascular communications that allow blood from the intestine to bypass the liver, and are classified as intrahepatic or extrahepatic. Clinical signs are generally related to the nervous, gastrointestinal or urinary systems, and are often vague. In addition, changes present on routine blood analysis are often mild and non-specific. For this reason, alternative tests are required for a diagnosis. Diagnostic tests include serum bile-acid concentrations, ammonia tolerance test, portography, ultrasonography and/or scintigraphy. Medical therapy involves reducing absorption of encephalopathic toxins from the gastrointestinal tract and may prolong survival. Surgical therapy is aimed at attenuation of the shunting vessel and provides improved survival rates. The traditional approach has been complete or partial ligation of the shunt. More recent approaches have involved slow, progressive attenuation with ameroid constrictors or cellophane banding. Overall, prognosis following surgical therapy is good in dogs and fair in cats.     

Congenital portosystemic shunts in cats: surgical management and prognosis

PRACTICAL RELEVANCE: Although the surgical management of feline congenital portosystemic shunts (CPSSs) is normally performed at specialist centres, a good knowledge of treatment options and prognosis is important for the general practitioner when advising clients. CLINICAL CHALLENGES: A variety of surgical techniques are described for the correction of CPSSs in cats. Choosing between the different techniques is a challenge, given the limited availability of evidence supporting one technique over another. In addition, postoperative complications, and in particular neurological complications, are seen more frequently in the cat than the dog and thus postoperative monitoring and treatment is critically important in feline patients. AUDIENCE: This article summarises current evidence in surgical management and is aimed at practising veterinarians, postgraduate students and specialists alike. EQUIPMENT: Surgical management of CPSSs typically requires advanced surgical and critical care facilities. The precise nature will depend to some extent on the technique employed. EVIDENCE BASE: The evidence base for decision making in the surgical management of CPSSs is relatively sparse. In reviewing the evidence that is available, as well as the areas in which information is still lacking, this article may hopefully serve as a stimulus for further investigation into this condition.     

Congenital portosystemic shunts in toy and miniature poodles

Three male Poodles (two Toy, one Miniature) were presented to their veterinarians for evaluation of urolithiasis and varying degrees of hepatic encephalopathy. All three dogs were diagnosed as having intrahepatic shunts and referred for surgical correction. In each case, shunts arose from the right branch of the portal vein and were amenable to perivascular dissection caudal to where the vessel entered the hepatic parenchyma and to placement of perivascular cellophane bands to achieve shunt attenuation. During the same period, a female Miniature Poodle also presented for treatment of a congenital portosystemic shunt discovered during evaluation for generalised motor seizures. This animal had an extrahepatic portoazygous shunt that was completely ligated. Congenital portosystemic shunts have not previously been identified in Toy and Miniature Poodles at the University Veterinary Centre, Sydney and the anatomical types of shunt seen in this breed have not previously been reported in a consecutive series of cases. The three male dogs are noteworthy for a number of reasons: all had intrahepatic shunts, despite being small breed dogs; all three presented in a similar fashion, and all had shunts of an anatomical type amenable to placement of cellophane bands. One male dog died within 12 hours of surgery, the remaining three dogs survived and their liver function was normal at follow-up between 2 and 3 months after surgery. Use of cellophane bands for successful attenuation of intrahepatic shunts has not been previously reported.     

Congenital portosystemic shunts in cats: investigation, diagnosis and stabilisation

PRACTICAL RELEVANCE: Although a relatively uncommon condition, the investigation, diagnosis and initial medical management of feline congenital portosystemic shunts is often undertaken within general practice. Early recognition and appropriate treatment are important to ensure a good outcome. CLINICAL CHALLENGES: Clinical signs associated with CPSSs in cats are extremely variable and can be intermittent. Signs can affect a variety of organ systems including the nervous system, and gastrointestinal and urinary tracts. Thus, the differential diagnosis list may be very long and a CPSS may not be suspected initially. More specific diagnostic tests and diagnostic imaging are indicated but may not be 100% accurate and may not be readily available to the general practitioner. AUDIENCE: This review highlights challenging aspects of the investigation and management of CPSSs for the practising veterinarian, but is also relevant to postgraduate students and provides a practical summary for specialists. PATIENT GROUP: In practice, domestic shorthairs make up the majority of cats with CPSSs. However, Siamese, Persian and Himalayan cats may be more commonly affected than other purebreeds. While cats with CPSSs are typically under 6 months old, the condition is seen in mature animals, which may not have exhibited clinical signs for months or years. EVIDENCE BASE: Despite several retrospective studies of cats with CPSSs, the evidence base for management of the condition remains limited.     

Congenital portosystemic shunts in Maltese and Australian Cattle Dogs

SUMMARY Congenital portosystemic shunts were definitively diagnosed in 62 dogs over a period of 15 years. Maltese and Australian Cattle Dogs were significantly over-represented, accounting for 14 and 13 cases, respectively. Maltese invariably had a single extrahepatic shunt derived from the left gastric or gastrosplenic vein, whereas Cattle Dogs usually had large intrahepatic shunts involving the right liver lobes. The clinical syndromes resulting from anomalous portosystemic communications were indistinguishable in the 2 breeds. Fasting blood ammonia concentration was elevated in 20 of 22 dogs tested, providing a minimally invasive and effective means of diagnosis. Complete or partial shunt attenuation was performed successfully in all 9 Maltese and in 2 of 6 Cattle Dogs in which it was attempted.     

Congenital portosystemic shunts in five mature dogs with neurological signs

Congenital portosystemic shunts are a common cause of hepatic encephalopathy and are typically first identified when dogs are <2 years of age. This case series describes five dogs with congenital portosystemic shunts; the dogs were presented for severe encephalopathic signs during middle or old age. Three dogs had portoazygos shunts, and four dogs had multifocal and lateralizing neurological abnormalities, including severe gait abnormalities and vestibular signs. All five dogs responded to medical or surgical treatment, demonstrating that older animals can respond to treatment even after exhibiting severe neurological signs.     

Pansteatitis in the cat: A report of four cases

Four cases of feline pansteatitis ('yellow fat disease') are presented and the characteristic clinical signs discussed. In three of the cats diagnosis was confirmed by biopsy and successful treatment instigated.     

Neurological dysfunction in three dogs and one cat following attenuation of intrahepatic portosystemic shunts

Neurological dysfunction is an uncommon complication following extrahepatic portosystemic shunt ligation. Three dogs and one cat are described that developed neurological signs within 21 to 42 hours of attenuation of intrahepatic portosystemic shunts. None of these cases had biochemical evidence of hepatic encephalopathy postoperatively. Two dogs died during management of status epilepticus following aspiration of food. One dog died six months postoperatively. The cat had persistent neurological dysfunction at discharge, but was alive and had recovered most of its neurological function at the time of writing, 37 months after surgery. This report demonstrates the potential for animals with intrahepatic portosystemic shunts to develop postoperative neurological signs and highlights the difficulty of managing such cases. Two dogs had both intrahepatic and extrahepatic portosystemic shunts. Large intestinal malrotation (partial situs inversus) may have been linked to the development of a portosystemic shunt in the remaining dog.     

Amyloid in the horse: a report of nine cases

Out of approximately 16,000 horses referred for clinical examination, nine had amyloidosis. Six of these horses had localised amyloid deposits in the wall of the nasal meatus and ventral turbinates associated with epistaxis. Horse 1 also developed malignant histiolymphocytic lymphosarcomas. The amyloid deposits were potassium permanganate-resistant and tryptophan-positive. Gel filtration of solubilised amyloid fibrils from Horse 1 revealed a major retarded fraction with an apparent molecular weight of 20 kD. This protein had an amino acid composition similar to human AL-amyloid proteins and horse immunoglobulin light chains. On Western blot a strong cross-reaction was observed between horse 1gG2a light chains and the Horse 1 amyloid. Horses 7 to 9 had suppurative verminous aneurysm, tuberculosis and an adrenal cortical adenoma, respectively, and had generalised amyloid deposits in liver and spleen. These amyloid deposits were found to be potassium permanganate-sensitive and positive for tryptophan. Gel filtration of solubilised amyloid fibrils from Horse 8 revealed a major retarded fraction (protein AA) with an apparent molecular weight of 10 kD. Immunoperoxidase-antiperoxidase staining showed the localised deposits to be negative or only weakly positive with antisera against bovine, hamster, dog and human protein AA and to be positive with anti-horse-one amyloid protein. The generalised deposits were found to be positive with the antisera against allogenic protein AA. The results of the potassium permanganate incubation, biochemistry, immunoblotting and immunochemistry, indicate that the localised amyloid of Horse 1 and most likely the amyloid of Horses 2 to 6, is of the AL-type. The generalised amyloid deposits were found to be of the AA type.