3.5. Liver + Biliary Tree Disease - Portosystemic Encephalopathy Flashcards
What is Portosystemic Encephalopathy?
This is a neuropsychiatric condition
What is Encephalopathy?
Irritation of the Brain
What is Portosystemic Encephalopathy secondary to?
Liver Cirrhosis / Hepatic Failure
What are the main predisposing factors to Portosystemic Encephalopathy?
- Gastrointestinal Haemorrhage
- Constipation
- Infection
- Drugs
- Fluid/Electrolyte Disturbances
- Surgical Procedures
- Toxic Substances
In which Group of people is Constipation a common source of Portosystemic Encephalopathy?
The Elderly
What infections can cause Portosystemic Encephalopathy?
- Urinary Tract Infections - These are the most common
- Chest Infection (URTI/LRTI)
- Spontaneous Bacterial Peritonitis - this must be rules out as a cause
What type of drugs can lead to Portosystemic Encephalopathy?
Central Nervous System Depressants
What can cause Fluid / Electrolyte Disturbances?
- Diuretic Therapy
2. Paracentesis
What Surgical Procedure, used in the Liver, can commonly lead to Portosystemic Encephalopathy?
Transjugular Intrahepatic Portocaval Shunt (TIPS)
What Toxic substances, in high levels, may be a causative factor?
- Ammonia
- Free Fatty Acids
- Thiols
- False Neurotransmitters (e.g. Octopamine)
- The activation of the Gamma-Aminobutyric Acid System (An inhibitory neurotransmitter)
What is the Pathology of Portosystemic Encephalopathy?
- The exact mechanism is unknown, but it is multifactorial
- Due to the Aetiology, Toxins are not deal with properly by the Liver
- These allow the Toxins to remain in the Blood which will irritate the Brain
What are the Clinical Signs of Portosystemic Encephalopathy?
- Asterixis (Hepatic Flap)
- Fetor Hepaticus
- Decreased Blood Pressure
- Decreased Blood Glucose
- Decrease Blood Urea
- Decreased Mental Function
- Confusion to Coma
What is Asterixis?
A flapping tremor caused by Hepatic Failure
What is Fetor Hepaticus?
Sweet Smelling Breath
Why does Fetor Hepaticus occur in Portosystemic Encephalopathy?
Portosystemic Shunting allows Thiols into the Lungs
Why might there be a Decrease in Blood Pressure / Urea?
If the patient goes into Renal Failure as a result of the Aetiology
Why might there be a Decrease in Blood Glucose?
Due to the Liver being damaged, and so unable to release the Glucose stored in it
How might the Decrease in Mental Function present?
- Drowsiness
- Constructional Apraxia
- Hyperreflexia
- Increased Tone
What is Constructional Apraxia?
The patient being unable to write / draw
What are Hyperreflexia and Increased Tone examples of?
Upper Motor Neuron Signs
Why might Upper Motor Neuron Signs occur?
Due to the irritation and effect on the Central Nervous System and the Brain
How is the Decreased Mental Function graded?
Grade 1 - Impaired Concentration
Grade 2 - Disorientation
Grade 3 - Confusion / Amnesia
Grade 4 - Coma
What are the Symptoms of Portosystemic Encephalopathy?
- Asymptomatic
- Infectious Markers (Fever, Nausea/Vomiting…)
- Psychogenic changes
When would Infectious Markers be present?
If an infection was the cause
What Psychogenic changed might occur?
- Irritability
- Confusion
- Disorientation
- Slow Slurred Speech
What investigations are required for Portosystemic Encephalopathy?
- Liver Function Test (and Biochemistry)
- Electroencephalography (EEG)
- Visually Evoked Responses
- Arterial Blood Ammonia
What are Liver Function Tests (and Biochemistry) Looking for?
Liver Function Test:
- Prothrombin Time
- Serum Albumin
Liver Biochemistry:
- Bilirubin
- Alkaline Phosphatase
- Gamma-Glutamyl Transpeptidase
- Aminotranferases:
a) Aspartate Aminotransferase
b) Alanine Aminotransferase
What is the purpose of the Liver Function Tests (and Biochemistry)?
To find the presence of Liver Disease
What is the purpose of Electroencephalography (EEG)?
To view the damage to the Brain
What will be shown on an Electroencephalography before a Coma occurs?
A decrease in the Frequency of Normal Alpha Waves
What do Visually Evoked Responses detect?
Subclinical Encephalopathy
What is the Purpose of Arterial Blood Ammonia?
To identify the cause of the irritation to the Brain
What is the Treatment of Portosystemic Encephalopathy?
To treat the underlying cause
How do you treat the underlying Infection?
Antibiotics
How do you treat the underlying Constipation?
- Laxatives (Dextrose / Lactulose)
2. Enema
How do you treat the underlying Electrolyte Disturbance?
Potassium Supplements
How do you treat the underlying Renal Failure?
Dialysis - this can also be used for severe hepatic failure
What general measures might be taken?
Nasogastric Tube - for medication
If the patient enters into a Coma, what will be required?
- Ventillation
2. I.V. access - for medication and nutrition
