What is Portal-Systemic Encephalopathy?
Portosystemic encephalopathy, also known as hepatic encephalopathy (HE), is a brain condition affecting patients with a disruption in blood flow called portosystemic shunt. This condition often affects patients with liver problems and causes mental and physical disturbances. If a person with liver trouble experiences mental or physical symptoms, doctors should suspect hepatic encephalopathy unless proven otherwise.
In a portosystemic shunt, the blood from the digestive system vessels bypasses the liver and flows into other veins. This disruption can be naturally present from birth (congenital) or happen later due to diseases (acquired). Congenital shunts are rare and can occur both inside and outside the liver, and these cases usually have no history of severe liver disease, high blood pressure in the liver portal vein, or clots in the portal vein. Acquired shunts often happen primarily due to liver scarring from end-stage liver disease, leading to high blood pressure in the portal vein. Both types of shunts can lead to hepatic encephalopathy.
This disruption in normal blood flow allows substances like ammonia and other neurotoxins, which the liver usually cleans up, to reach and accumulate in the brain. This build-up can cause disturbances in cognition (thinking, understanding) and psychomotor function (coordination between the brain and muscles).
What Causes Portal-Systemic Encephalopathy?
Hepatic encephalopathy is a condition that tends to occur in people with liver scarring, also known as liver cirrhosis. This condition can be classified into three types depending on what causes it:
* Type A: It happens due to acute liver failure
* Type B: It occurs due to an abnormal connection between the portal system (veins coming from the stomach, intestine, spleen, and pancreas) and the systemic circulation in patients who don’t have any liver dysfunction
* Type C: It develops in those who have liver cirrhosis
The main cause of hepatic encephalopathy, regardless of the type, is that the liver fails to convert ammonia, a harmful substance, into a less toxic form. This failure can occur due to a malfunctioning liver or the development of an abnormal connection between the portal and systemic circulation.
The cells that make up the brain, known as astrocytes, can absorb ammonia. Even a small amount of ammonia can cross the protective barrier between the blood and the brain, and accumulate in the brain. Excess ammonia in the brain can lead to a range of mental and physical symptoms, a phenomenon known as neuropsychiatric syndrome.
Risk Factors and Frequency for Portal-Systemic Encephalopathy
Hepatic encephalopathy’s exact occurrence rate in the general population is unidentified. This disease, which impacts the brain due to liver problems, can affect anyone, regardless of gender or age. It ranks as the fourth leading cause of death in Americans between 45 and 54 who have liver disease. It’s connected to 50% to 70% of all people with liver cirrhosis, a severe liver condition. The earliest form, known as minimal hepatic encephalopathy (MHE), may affect up to 80% of people with liver cirrhosis.
Around 23% to 53% of individuals with no liver disease, but where their liver has been bypassed by a medical procedure known as a portosystemic shunt, can also develop hepatic encephalopathy. Liver cirrhosis is the most common cause of this condition and is estimated to affect 5.5 million people in the United States alone. Countries with higher rates of liver disease than the United States also have a higher chance of hepatic encephalopathy.
Signs and Symptoms of Portal-Systemic Encephalopathy
Hepatic encephalopathy, a condition linked to chronic liver disease, can present with a variety of signs and symptoms. These may be mild in the beginning but can progress to severe symptoms if not addressed promptly.
- Hyperreflexia (overactive or overresponsive reflexes)
- Rigidity
- Tremors
- Positive Babinski’s sign (an abnormal response to a stimulus in the foot)
- Asterixis (sudden, jerky movements especially in the hands)
- Agitation
- Disorientation in time, place, and person
- Increased sleepiness
- Rapidly developing confusion
- Progression to coma in severe cases
Testing for Portal-Systemic Encephalopathy
To diagnose hepatic encephalopathy, which is a condition that affects brain function due to liver disease, a comprehensive physical check-up of the patient is necessary. The patient’s symptoms and signs are then classified according to a standard known as the West Haven criteria. It’s also key to make sure that other brain-related conditions like viral encephalopathy (brain diseases induced by viruses), brain lesions (areas of injury or disease), hemorrhage (bleeding) or stroke, post-seizure encephalopathy (brain disorder following seizures), brain infections, or toxic encephalopathy (brain disease due to toxic substances) are not the actual causes of the observed symptoms.
The diagnosis of hepatic encephalopathy relies on four main aspects:
1. The patient exhibits a specific pattern of symptoms.
2. The patient is diagnosed with liver disease or a condition called portosystemic shunt (abnormal blood flow between the liver and the rest of the body), along with a condition called hyperammonemia (high levels of ammonia in the blood).
3. Other possible causes have been ruled out.
4. The patient responds positively to treatments that reduce blood ammonia levels.
Additional techniques like an electroencephalogram (EEG), which is a test that measures the electrical activity of the brain, computed tomography (CT) scan, an imaging test that provides detailed pictures of the body, and magnetic resonance imaging (MRI) of the head might also be used to help rule out other causes of encephalopathy (brain diseases).
Treatment Options for Portal-Systemic Encephalopathy
Hepatic encephalopathy is a disease that often lands patients in the hospital. Treating hepatic encephalopathy involves taking preventative measures, changing diet, and in some cases, a liver transplant may be needed.
Preventative measures are divided into primary and secondary measures. Primary prevention aims to reduce the risk of developing hepatic encephalopathy for the first time. Those who have already had a severe gastrointestinal bleed are at a high risk of developing hepatic encephalopathy. Rinsing the stomach with a substance like mannitol or non-absorbable disaccharides can help reduce this risk. Treatments that slow down or even reverse the course of liver disease can also act as primary prevention. This can include cutting out alcohol in those who misuse it, using antiviral drugs in cirrhosis caused by viruses, eating a balanced diet, and avoiding iron overload.
Secondary prevention aims to reduce the risk of getting hepatic encephalopathy again for those who have already had it. Using lactulose, a type of laxative, after an episode can cut the chances of another episode by half. Rifaximin, a type of antibiotic, can be used by those who can’t tolerate lactulose. For those who have repeated episodes of hepatic encephalopathy, both lactulose and rifaximin can be used together for even better prevention. In very severe cases, the goal might be to locate and remove a shunt, an abnormal connection between blood vessels.
There are also advised dietary changes for patients with hepatic encephalopathy. Adding snacks in between meals and before bedtime can help reduce the breakdown of proteins. Decreasing the intake of meat proteins and replacing them with milk proteins may be a good idea. Increasing dietary fiber, taking prescribed vitamins and minerals, and adding probiotics to the diet are other options.
For patients who have a high risk of inhaling food into their lungs or have trouble with their breathing, a tube may be inserted into their windpipe to keep it open. They would also need to be watched in the ICU.
Finally, although a liver transplant might sound like a good solution, patients with hepatic encephalopathy usually do not fare well after a liver transplant. The prognosis tends to be poor and there is often a significant decrease in quality of life after the transplant.
What else can Portal-Systemic Encephalopathy be?
Some conditions could have similar symptoms to intracranial lesions, which include:
- Intracranial hemorrhage (bleeding inside the skull)
- Abscess (pocket of pus)
- Tumor (abnormal growth of cells)
- Stroke (brain damage from blood supply getting cut off)
- Subdural hematoma (bleeding on the brain surface)
- Meningitis (inflammation of the brain and spinal cord membranes)
- Hypoglycemia (low blood sugar)
- Anoxia (lack of oxygen to your tissues)
- Wernicke encephalopathy (brain disorder due to vitamin B1 deficiency)
- Post-seizure encephalopathy (brain dysfunction following a seizure)
- Certain drugs such as antipsychotics, sedatives, and antidepressants
What to expect with Portal-Systemic Encephalopathy
Hepatic encephalopathy, a condition affecting the brain due to liver disease, tends to have a negative outlook in terms of patient survival and recurrence of the condition. This health issue significantly impacts patients’ quality of life and also places a considerable burden on those taking care of them.
Furthermore, individuals with this medical condition are at a greater risk of accidental falls and have impaired driving skills. It may even have economic implications, often being associated with a decrease in income.
Possible Complications When Diagnosed with Portal-Systemic Encephalopathy
These are some serious effects that can occur:
- Intense confusion
- Changes in movement and coordination
- Difficulty recognizing familiar places, people, or things
- Feeling unusually sleepy or drowsy
- Changes in thinking skills
- Falling into a coma
- Death
Preventing Portal-Systemic Encephalopathy
People with a medical condition called hepatic encephalopathy can have various signs and symptoms show up. These might include overly responsive reflexes (hyperreflexia), stiffness (rigidity), shaking (tremors), and positive Babinski’s sign or asterixis—these are specific physical responses doctors look for when examining patients. When hepatic encephalopathy becomes severe, the patient might become agitated, disoriented (having trouble knowing who they are, where they are, or what time it is), very sleepy, quickly become confused, and ultimately end up in a coma.
When a patient gets diagnosed with this condition, emotional support and detailed information about their condition should be provided. This includes information about the treatment, what to expect in the future (prognosis), and how it may affect their daily life.
It’s also important for patients to have learning materials about their illness. Tools like flow charts, diagrams, and videos can be used to help explain everything about their disease, treatments, and changes they may need to make in their lifestyle. This education should continue until the patient fully understands everything and is happy with the medical care they’re receiving.
