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Showing posts with label hepatic encephalopathy. Show all posts
Showing posts with label hepatic encephalopathy. Show all posts

How to elicit the signs of liver cell failure an OSCE guide

Following are the major signs of liver cell failure
3.Constructional Apraxia
Presence of a Button-like' breast tissue on palpation below the areola In a male suggests early gynaecomastla.
5.Testicular Atrophy
If the testis is less than 3.5 cm in length, and feels soft or
Flabby on  palpation, it suggests testicular atrophy.
6.Loss of Axillary and Pubic Hairs
They become sparse initially and are totally absent in later stages.

This is very important for those students preparing for USMLE and MRCP

Pathogenesis of hepatic encephalopathy

Hepatic encephalopathy is a complex neuro psychiatric syndrome that is caused by liver disease. 
This will manifests as disturbances in
1.Consciousness and behaviour.
2.Personality changes.
4.Distinctive electroencephalographic changes
It may present as 
Acute and reversible form
Chronic and progressive form
Severe cases  may leads to coma, later on death 
Occur in severe hepatocellular dysfunction.

Main  mechanism of hepatic encephalopathy is porto systemic shunting of blood.
This is a complication of portal HTN.
There is obstruction to the passage of blood  absorbed from the intestine to go through liver. As there is no valves in the portal venous system it will facilitates retrograde blood flow to the lower pressure systemic venous circulation. So the portal blood bypass the liver and it reaches the systemic circulation without undergoing the 1st pass detoxification. There is portal systemic collateral formation.The major sites of collateral are Gastro oesophageal junction, umbilicus, anal canal and posterior abdominal wall.

Toxic substances accumulated in hepatic encephalopathy are
False neurotransmitters
Mercaptans(methionine metabolism)
Short chain fatty acids
GABA(Gama-aminobutyricacid) inhibitory neurotransmitter
Endogenous benzodiazepine acting through GABA receptors 
What these neurotransmitters will do?
1. These neurotransmitters will causes the supporting cells of the brain (astrocytes) to swell. Which inturn increases the intracranial pressure, leading  to herniation of brainstem and death
2. There will be disruption of the blood brain barrier leading to cerebral edema. 

Factors precipitating hepatic encephalopathy

Patients with chronic liver disease are prone to hepatic encephalopathy which manifest as altered sensorium. It may be precipitated by a variety of causes which can be prevented.

1. Increased nitrogen load
Increased nitrogen load is seen in the following conditions
Gastrointestinal bleeding, since the blood contain large quantity of proteins when there is GI bleed, there will be protein load in intestine.It is acted upon by intestinal bacteria leading to  increased NH3
Excess dietary protein intake.

2. Electrolytic imbalances
Hypokalemia(secondary to diuretic therapy, paracentesis,vomiting) stimulates renal NH3 production.
Systemic alkalosis.

3. Drugs
Diuretics produce electrolyte imbalance
Narcotics, sedatives

4. Infections
Superimposed acute viral hepatitis
Alcoholic hepatitis
Extrahepatic bileduct obstruction

5. Surgeries