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

Following are the major signs of liver cell failure

1.Spider naevus

2.Asterixis or flapping tremor

3.Constructional Apraxia

4.Gynaecomastla

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

Clinical presentation of hepatic encephalopathy

Pathogenesis of hepatic encephalopathy

Factors precipitating hepatic encephalopathy

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.

3.Asterixis.

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

Octopamine 

Ammonia 

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.

Azotemia

Constipation

2. Electrolytic imbalances

Hypokalemia(secondary to diuretic therapy, paracentesis,vomiting) stimulates renal NH3 production.

Systemic alkalosis.

Hyponatremia

Hypovolemia

3. Drugs

Diuretics produce electrolyte imbalance

Narcotics, sedatives

4. Infections

Superimposed acute viral hepatitis

Alcoholic hepatitis

Extrahepatic bileduct obstruction

5. Surgeries