hepatic encephalopathy Flashcards
What is hepatic encephalopathy?
Hepatic encephalopathy is brain dysfunction caused by advanced liver insufficiency
Causes and risk factors for this:
- Cirrhosis
- liver cancer
- Hepatitis,
- Intestinal Bleed
Pathophysiology of hepatic encephalopathy
Decreased Liver function → build up of toxic metabolites (NH3) → Astrocyte ion channels activated, increased production of cytokines and stimulation of osmotic pumps → swelling of astrocytes → contributes to cerebral oedema =
NEUROLOGICAL CHANGES
Presentation of hepatic encephalopathy?
Mood Disturbances – Depression Sleep Disturbances – Insomnia
Motor Disturbances – Ataxia, Muscle Rigidity, Bradykinesia
Confusion
Liver Symptoms too – ascites, jaundice, peripheral oedema
Diagnosis and investigations
FBC and Basal Metabolic Panel
Blood Alcohol
Blood ammonia – raised
1st line treatment
1st Line: Lactulose
2nd line treatment
Rifaximin – reduces number of ammonia producing intestinal bacteria
Liver transplant
Complications of hepatic encephalopathy
Cerebral Oedema
Aspiration Pneumonia
What is it caused by
build up of toxins that affect the brain.
Which toxin predominantly affects the brain in HE?
Ammonia - produced by intestinal bacteria when they break down proteins and is absorbed in the gut
2 reasons ammonia builds up in blood in patients with cirrhosis
- functional impairment of the liver cells prevents them metabolising the ammonia into harmless waste products.
- collateral vessels between the portal and systemic circulation mean that the ammonia bypasses liver altogether and enters the systemic system directly.
How do we manage HE?
Laxatives (i.e. lactulose) promote the excretion of ammonia. The aim is 2-3 soft motions daily. They may require enemas initially. help clear the ammonia from the gut before it is absorbed and by giving antibiotics we reduce the number of bacteria in the gut producing ammonia.
Antibiotics (i.e. rifaximin) reduces the number of intestinal bacteria producing ammonia. Rifaximin is useful as it is poorly absorbed and so stays in the GI tract.
Nutritional support. They may need nasogastric feeding.
Precipitating factors
Constipation
Electrolyte disturbance
Infection
GI bleed
High protein diet
Medications (particularly sedative medications)