Hepatic encephalopathy

The hepatic encephalopathy is a neuropsychiatric syndrome characterized by potentially reversible mental and neuromuscular abnormalities that may occur during multiple clinical situations related to the liver, such as hepatic failure severe acute diseases chronic liver, disturbances in blood circulation liver, etc. .

Its evolution and clinical significance is different depending on the primary pathology that produces it.

In the case of chronic liver diseases, acute episodes can occur more or less frequently, generally reversible, although some episodes may have a poor evolution, leading to coma and death.

Causes of hepatic encephalopathy

There are many causes that can trigger the development of hepatic encephalopathy in chronic liver patients, such as a UGH (common), a high protein diet, constipation , kidney failure, certain medications (diuretics), infections or surgical interventions.

All these causes would have a final common effect, which would be responsible for the development of encephalopathy. Although at present the intimate mechanisms that lead to encephalopathy are not clear, it seems that the ultimate responsible cause would be the accumulation in the blood of toxic substances, mainly ammonia, which under normal conditions are metabolized by the liver.

Even though the mechanisms involved in the development of the disease are not exactly known, it is currently accepted that there are two determining factors:

• On the one hand, severe liver failure, which would prevent the liver from eliminating toxic substances.
• On the other hand, the existence of abnormal blood routes through which the blood would pass directly from the portal vein to the general circulation, thus avoiding the hepatic passage and, therefore, its “purifying” function.

As noted above, ammonia is the substance most commonly implicated in hepatic encephalopathy (although not the only one). Once it accumulates in the blood, it reaches the central nervous system , where it interferes with its normal functioning.

There are also alterations in certain neurotransmitters of the nervous system, whose levels are increased due to liver failure, thus contributing to the neurological alterations that appear in this picture.

Symptoms of hepatic encephalopathy

The clinical manifestations are highly variable, and practically any neurological alteration can appear (attention deficit, seizures, coma, tremors, muscular rigidity, etc.).

Within the neurological manifestations, asterixis is practically constant. Clinically, it manifests as a fine tremor, more evident when the patient is asked to keep the arms extended upwards, with the hands bent back and the fingers apart.

Psychiatric manifestations are also frequent, such as delirium, aggressiveness, euphoria, depression or sleep disorders. These manifestations will be more serious depending on the stage (I to IV) in which the encephalopathy is found.

In patients with acute encephalopathy, these symptoms are reversible once the previously described triggers have been corrected.

In patients with chronic encephalopathy, the deterioration can be irreversible and progressive, leading to coma and death. Frequently there is cerebral edema , which contributes to the appearance of the clinical picture and its mortality, both in acute and chronic cases.

How is it diagnosed?

The symptoms, although variable, usually guide towards the diagnosis, especially if it appears in a patient with known chronic liver disease. The presence of asterixis is also very indicative of this disorder.

There is no laboratory data to diagnose hepatic encephalopathy, including elevated levels of ammonia in the blood, since this is an inconsistent finding and the variations of which are not related to the degree of encephalopathy.

Alterations in the EEG recording can be observed, although they are not specific or different from those that appear in other metabolic disorders of the central nervous system. Tests such as CT or MRI will allow us to rule out brain lesions that could produce the same symptoms.

Treatment of hepatic encephalopathy

It is a pathology of hospital management. Its treatment is complex and is largely determined by the initial trigger:

On the one hand, general life support measures will be necessary to avoid serious complications derived from the patient’s condition (pneumonia, urinary infection ).

On the other, we will carry out the specific treatment of the cause that led to the encephalopathy:

• If it is an HDA, it will be necessary to stop it, by endoscopy if necessary, as well as to replace the lost blood volume.
• If the cause is the drugs the patient was taking (mainly diuretics), they should be stopped immediately and the change in treatment evaluated upon discharge.
• Regarding constipation, laxatives such as lactulose or lactitiol are often used to prevent its appearance.
• In the event that the cause is an infection, the treatment will be specific to it.

As a prophylactic, paromomycin is also used, an antibiotic that acts in the intestine by reducing the number of bacteria that are part of the normal bacterial flora.

How can I avoid it?

Patients with chronic liver diseases must strictly follow the treatment prescribed by their doctor to avoid the appearance of hepatic encephalopathy.

They will follow a low-protein diet, take the laxative drugs previously described (whenever their doctor considers it appropriate) and consult their doctor with any questions that may arise regarding treatment.

Whenever the patient with chronic liver disorders notices any neurological disorder (difficulty in movement, stiffness, sensitivity alterations) or their relatives detect psychiatric disorders, they should go to the emergency room of a hospital.