Cerebral intoxications: hepatic or porto-systemic encephalopathy

By Cristiano Antonino On Nov 16, 2022

Patients who present with a liver disease (cirrhosis of the liver) often experience peculiar and most often difficult to understand symptoms. One of these is what is known as hepatic or porto-systemic encephalopathy

Hepatic or porto-systemic encephalopathy is a neuropsychiatric syndrome (i.e. a set of symptoms) linked to intoxication of the brain by proteinaceous substances, with intestinal ammonium as the trigger.

Symptoms of hepatic or portosystemic encephalopathy

In the advanced stage of cirrhosis, the liver shrinks, becomes hard and balky: in this situation the blood coming from the intestine, rich in substances absorbed during digestion, passes through it with great difficulty.

In order to reach the heart, the blood takes other routes (called collateral circles), but in this way it is no longer cleansed of harmful substances and in particular of ammonium, which is produced in the intestine from the breakdown of meat proteins.

The ammonium-rich blood then reaches the brain and instead of supplying the cells with substances that are useful for the formation of normal intercellular transmitters (neurotransmitters), it supplies them with others that favour the formation of slower and slower transmitters.

This alteration leads to a progressive slowing down of brain function until a state of coma (unconsciousness) ensues.

This situation is initially manifested by:

a fine tremor of the hands
a state of nocturnal insomnia and daytime sleepiness (particularly postprandial)
unpredictable mood swings
an altered critical sense
a slowness of speech and confusion of terms (using the wrong words to indicate well known things).

The patient has the belief that the people around him are different from those with whom he usually lives and this leads him to spatial and temporal disorientation.

The underlying problem is that the patient with encephalopathy is convinced that he is doing and saying the right things and becomes increasingly irritated because he realises that the people around him do not understand or rather do not want to understand what he is asking, saying or wanting.

The situation, if not stopped in time, evolves towards a progressive state of cerebral slowing down to a state of progressive sleep that preludes, as we have said, the state of coma (reversible).

A characteristic early sign of hepatic encephalopathy is what is known as constructive apraxia, i.e. the inability to make simple drawings (e.g. a star) due to hand tremor and difficulty in concentrating on executing a shape. In these cases, the patient often presents a typical sweetish breath odour, called fetor hepaticus (liver odour).

In addition, if the patient stretches his arms forward with his wrists flexed backwards, a characteristic rhythmic, flapping tremor (flapping tremor or asterixis) occurs; as the confusional state progresses, this sign disappears and is replaced by an abnormal increase in reflexes.

Causes of hepatic encephalopathy

Hepatic encephalopathy can occur in hepatitis caused by viruses, alcohol, drugs or toxins but, more commonly, by specific, potentially reversible causes, of which the most important in order of frequency is undoubtedly constipation.

Other causes are:

gastrointestinal bleeding
infections
electrolyte imbalance (especially low blood potassium)
abuse of alcohol or drugs such as tranquillisers or sedatives (increase mental confusion), painkillers, diuretics.

Constipation leads to a blockage of stools in the intestine, which encourages the production and accumulation of ammonium in the intestine and thus in the blood with the consequences we have mentioned.

Bleeding induces an increase of nitrogen also in the intestine and thus of ammonium which follows the path already mentioned.

On the other hand, sedatives, often used in the past to try to calm the irritability of patients undergoing encephalopathy, have serious effects in that they increase the state of confusion and thus the state of irritability that can no longer be controlled.

Diuretics used in an uncontrolled manner (excess) lead to a loss of salts in the blood (lowering of sodium and particularly potassium), lead to kidney failure and a change in blood acidity, which in turn leads to an increase in ammonium in the blood, which triggers the above-mentioned events.

Infections (high fever) also alter blood acidity and give rise to the same effects.

Often the infection then manifests itself in the ascitic fluid in the belly.

Fluid sequestration in the abdomen and kidney failure have a very serious triggering effect on encephalopathy.

Diagnosis of hepatic encephalopathy

Encephalopathy is a neurological manifestation that frightens relatives living with the patient very much because, particularly the first few times it occurs, they are unable to understand what it is due to and how to cope with it.

Over time, the relatives gradually learn to see the premonitory signs and thus, if they are taught what to do, they are able to master the clinical picture quickly and before the patient adopts attitudes that are difficult to control.

We have seen what the premonitory signs are, i.e. slowing down in the pronunciation of words and difficulty in using commonly used correct words, a state of mental confusion, and so on.

Generally, if there are no signs of other pathological manifestations (bleeding, infection, kidney failure – the patient does not urinate or urinates little and has a lot of water in the belly), constipation is the cause.

What to do in the case of hepatic encephalopathy

In this case the first thing to do is to clean the intestines of faeces with an enema (one and a half litres of lukewarm water from the tap with a tablespoon of oil.

Insert the nozzle gently into the anus, with the patient on their stomach, with a pillow on the belly to raise the level of the buttocks in relation to the chest.

Then open the water tap and let the liquid enter the bowel at low speed to avoid the immediate defecation reflex.

Convince the patient to hold the position and the water in the bowels for at least fifteen to twenty minutes and afterwards go to the toilet to flush the faeces).

This manoeuvre can be repeated several times during the day until the neurological situation normalises

It is recommended not to use the ready-made perette, which one buys in pharmacies, because these only have an irritating effect without producing the effects of intestinal lavage (enema devices are sold in pharmacies and are reusable).

However, this situation must be prevented by using special laxatives by mouth on a daily basis, i.e. Lactulose EPS (it is important that in the prescription along with the name of the drug there is the abbreviation EPS, which stands for Encephalopathy Porto Systemica.

This is understood because the acronym must be written by the doctor in the prescription and the drug must be given by the pharmacy free of charge without payment of the co-payment).

This syrup (there are various formulations in pharmacies with different flavours) is a sugar that alters the bacterial flora and pH of the colon, eliminating ammonium-producing bacteria, and also has an osmotic (non-irritating) laxative effect.

The initial dose is 30-45 ml three times a day (i.e. one or two tablespoons) and this must be adjusted subsequently to allow at least 2 or 3 daily evacuations of soft stools.

Secondly, one can add the daily administration of particular antibiotics such as neomycin by mouth at a dose of 4-6 g/day, in 4 divided doses.

This antibiotic is useful in reducing the amount of toxins formed by the bacteria in the gut and can be used instead of or in combination with lactulose.

With the progression of the liver disease or in the presence of a TIPS (a prosthesis that is placed in the liver to join the portal vein to the supra-hepatic vein, to prevent or treat portal thrombosis or intractable ascites or haemorrhages from ruptured varices, which do not respond to endoscopic treatment), encephalopathy turns from an episodic acute form into a chronic form that is more difficult to treat.

In these cases, the above-mentioned treatments must be daily, combined with the use of specific drugs (selective amino acid solutions in phleboclysis, etc.).

These situations generally require hospitalisation also because they are often associated with other morbid conditions, such as infections, renal failure, diabetic decompensation, etc.

The only realistic solution to the problem at this point is liver transplantation.

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