Hepatic encephalopathy

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Sections available in full article Introduction, Presenting signs, Acute presentation, Age predisposition, Breed predisposition, Cost considerations, Special risks (e.g. anesthetic), Pathogenesis, Etiology, Predisposing factors, Pathophysiology, Timecourse (incubation, duration), Diagnosis, Presenting problems, Client history, Clinical signs, Diagnostic investigation, Confirmation of diagnosis, Gross autopsy findings, Histopathology findings, Differential diagnosis, Treatment, Initial symptomatic treatment, Standard treatment, Monitoring, Sequelae, Prognosis, Expected response to treatment, Reasons for treatment failure, Sources, Publications, Vetstream contributor(s),
Contributors Mr Paul Cuddon BVSc DipACVIM
Mr James Simpson SDA BVM&S MPhil MRCVS
Dr Laurent Garosi DVM DipECVN MRCVS
Synonyms HE

Introduction

  • Signs : alteration in behavior (sometimes profound), eg head pressing, disorientation, seizures, ataxia and collapse, and depression. Episodes may be related to feeding.
  • Cause : exact cause is unknown but results from the liver being unable to remove toxic products of gut metabolism and to synthesize factors necessary for normal brain function.
  • Underlying disorders: congenital portosystemic shunts Portosystemic shunt , urea cycle enzyme deficiencies, or acquired portosystemic shunts secondary to other hepatic disease, eg severe parenchymal liver damage due to cirrhosis, neoplasia, drugs, infection or toxins.
  • Diagnosis : demonstration of hepatic dysfunction and response to treatment.
  • Treatment : fluid therapy, surgery, diet change, medical therapy, eg antibiotics, lactulose, 10% betadine solution enemas, emergency if in hepatic coma.
  • Prognosis : good to fair.

Diagnosis

Clinical signs

  • Disorientation.
  • Head pressing.
  • Blindness.
  • Seizures.
  • Ataxia.
  • Collapse.
  • Behavior change.
  • Hepatic coma.

Diagnosis

Differential diagnosis

  • Other metabolic diseases affecting the brain, eg hypoglycemia Hypoglycemia , electrolyte imbalances, hypothyroidism Hypothyroidism.
  • Congenital brain diseases, eg hydrocephalus Hydrocephalus.
  • Encephalitis Encephalitis /meningitis Meningitis - bacterial, viral (distemper Canine distemper disease ), fungal, rickettsial.
  • GME Granulomatous meningoencephalomyelitis.
  • Neoplasia (older animals).
  • Toxicities.

Sequelae

Prognosis

End stage hepatic cirrhosis
  • Poor even with proper dietary therapy and medical management.
Congenital portosystemic shunt
  • Good for full recovery if treated in early stages, ie not in hepatic coma with edema.
  • Residual neurological defects may persist for long periods after recovery from hepatic coma.
  • Dogs most commonly die post shunt ligation due to post surgical status epilepticus.
  • Surgical ligation of shunts more likely to be successful if diagnosis and treated before cirrhosis or age.

Expected response to treatment

  • A substantial decrease in, to total reversal of, neurological signs.

Reasons for treatment failure

  • Incorrect diagnosis.
  • General anesthetic complications.
  • Portal hypertension.
  • Post-surgical status epilepticus.

Sources

Publications

Refereed papers

  • Recent references from PubMed.
  • Mai W, Weisse C (2011) Contrast-enhanced portal magnetic resonance angioraphy in dogs with suspected congenital portal vascular anomalies. Vet Radiol Ultrasound 52, 284-288 PubMed.
  • Gommeren K, Claeys S, de Rooster H, Haide A, Daminet S (2010) Outcome from status epilepticus after portosystemic shunt attentuation in 3 dogs with propofol and phenobarbital. J Vet Emerg Crit Care 20 , 346-351 PubMed.
  • Greenhalgh S N, Dnuning M D, McKinley T J, Goodfellow M R, Kelman K R, Freitag T, O'Neill E J, Hall E J, Watson P J, Jeffrey N D (2010) Comparison of survival after surgical or medical treatment in dogs with a congenital portosystemic shunt. JAVMA 236 , 1215-1220 PubMed.
  • Ruland K, Fischer A, Hartmann K (2010) Sensitivity and specificity of fasting ammonia and serum bile acids in the diagnosis of portosystemic shunts in dogs and cats. Vet Clin Pathol 39, 57-64 PubMed.
  • d'Anjou M A, Penninck D, Cornejo L, Pibarot P (2004) Ultrasonographic diagnosis of portosystemic shunting in dogs and cats. Vet Radiol Ultrasound 45 , 424-437 PubMed.
  • Winkler J T et al(2003) Portosystemic shunts: diagnosis, prognosis, and treatment of 64 cases (1993-2001). JAAHA 39 , 169 PubMed.
  • Watson P J, Herrtage M E (1998) Medical managment of congenital portosystemic shunts in 27 dogs - a retrospective study. JSAP 39 , 62 PubMed.
  • Watson (1997) Decision making in the management of portosystemic shunts. In Practice 19 , 106-120.
  • Cuddon P A (1996) Metabolic encephalopathies. Vet Clin Nor Am Intracranial Disease 24 (4), 893-923.
  • Torboada & Dimski (1995) Hepatic encephalopathy; clinical signs, pathogenesis and treatment. VCNA 25 , 337-355.
  • Maddison J E (1994) Hepatic encephalopathy in dogs and cats. Vet Int 6 , 37-43.
  • Maddison J E (1992) Current concepts of hepatic encephalopathy. JVIM 6 , 341-343.

Other sources of information

  • Tobias K M (2003) Portosystemic shunts and other hepatic vascular anomalies. In: Textbook of Small Animal Surgery.3rd edn, Slatter D (ed), Philadelphia, p 727.
  • LaFlamme D P (2000) Nutritional management of liver disease. In: Current Veterinary Therapy XIII. Bonagura J (ed), W B Saunders, Philadelphia. pp 683-687.

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Abdomen: cirrhosis - portal venogram Link Abdomen: portosystemic shunt - portal venogram Link Hepatic encephalopathy Liver: cirrhosis (diffuse hyperechogenicity) - ultrasound Link Liver: microhepatica - radiograph Link

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