Hepatic/uraemic encephalopathy Flashcards
What are 6 clinical features of hepatic encephalopathy?
- Confusion
- Altered GCS
- Asterixis: liver flap
- Constructional apraxia: inability to draw 5-pointed star
- Triphasic slow waves on EEG
- Raised ammonia level (no longer commonly measured)
What is thought to be the aetiology of hepatic encephalopathy?
can be seen in liver disease of any cause. aetiology not fully understood but is thought to include excess absorption of ammonia and glutamine from bacterial breakdown of proteins in the gut
Does hepatic encephalopathy occur in acute or chronic liver disease?
commonly associated with acute liver failure, but may be seen in both
What features may patients develop before the features of hepatic encephalopathy become recognisable?
mild cognitive impairment + other subtle symptoms
What iatrogenic procedure has now been noted to be able to precipitate encephalopathy?
transjugular intrahepatic portosystemic shunting (TIPSS) - due to reduced absorption by the liver of nitrgenous waste (as portal circulation bypassing liver to hepatic vein)
What are the 4 grades of hepatic encephalopathy?
- Grade I: irritability
- Grade II: confusion, inappropriate behaviour
- Grade III: incoherent, restless
- Grade IV: coma
What are 8 precipitating factors for hepatic encephalopathy?
- Infection e.g. spontaneous bacterial peritonitis (SBP)
- GI bleed
- Post- transjugular intrahepatic portosystemic shunt
- Constipation
- Drugs: sedatives, diuretics
- Hypokalaemia
- Renal failure
- Increased dietary protein (uncommon)
What are 3 key aspects of the management of hepatic encephalopathy?
- Treat any underlying precipitating cause
- Lactulose first line
- Rifaximin for seconary prophylaxis of HE
What is the first line treatment for hepatic encephalopathy?
lactulose
How is lactulose thought to work to treat hepatic encephalopathy?
promoting excretion fo ammonia and increasing metabolism of ammonia by gut bacteria
What is the role of rifaximin for treating hepatic encephalopathy?
antibiotic thought to modulate the gut flora resulting in decreased ammonia production - for secondary prophylaxis of hepatic encephalopathy
What are 2 further management options for hepatic encephalopathy in addition to first line treatments, that vary depending on the cause?
- Embolisation of portosystemic shunts
- Liver transplantation
What is typically seen on EEG in hepatic encephalopathy?
triphasic slow waves
What is liver flap?
arrhythmic negative myoclonus with a frequncy of 3-5 Hz
What causes uraemia?
results from buildup of nitrogenous waste normally excreted, in renal failure
What are 8 clinical features of uraemia?
- Nausea and vomiting
- Itching
- Lethargy
- Bleeding
- Drowsiness
- Confusion
- Convulsions
- Death
What are the 2 key life-threatening complications of uraemia?
- Uraemic pericarditis
- Encephalopathy
What are the 2 situations when acute dialysis is indicated for uraemia?
- Uraemic pericarditis
- Uraemic encephalopathy
What are 9 clinical features of uraemic encephalopathy?
- Fluctuating alertness and decreased concentration
- Drowsiness
- Delirium with visual hallucinations and coma
- Tremulousness
- Asterixis (flapping tremor)
- Myoclonus
- Seizures
- Brisk reflexes incl. upgoing plantars
- Autonomic neuropathy
What are 3 investigations to perform in uraemic encephalopathy?
- CSF: lymphocytosis, increased protein
- EEG: diffuse slowing with triphasic waves
- CT/MRI to exclude other pathology
What may CT/MRI show in uraemic encephalopathy?
oedmea, focal infarcts, haemorrhage
How can serum urea and fractional urea excretino tell us about the nature of kidney disease?
serum urea : creatinine ratio is raised in pre-renal uraemia but normal in acute tubular necrosis (underperfusion of kidneys)
fractional urea excretion is <35% for pre-renal uraemia and >35% for acute tubular necrosis
How can uraemia contribute to anaemia in renal failure?
although reduced EPO production is the most significant factor, urea contributes further due to toxic effects of uraemia on bone marrow whcih reduces erythropoiesis, and anorexia/nausea due to uraemia can further contribute
What is the key management for uraemic encephalopathy?
renal replacement therapy - emergency haemodialysis
