Portal Hypertension and Ascites
Portal hypertension is most often caused by difficulty in blood flow into the liver, which then causes a build-up of pressure. As blood travels around the body it goes through the digestive system to pick up the nutrients from food which has been eaten. This blood then takes these nutrients to the liver through a blood vessel called the portal vein. This is called the portal circulation. The liver processes the blood before it goes back to the heart.“Hypertension” means high blood pressure. When the pressure of the blood in the portal circulation is unusually high this is known as portal hypertension.
The main causes of this happening are:
A blockage in the portal vein. This can happen if a blood clot (thrombus) stops the blood from passing through the portal vein freely. This is called portal vein thrombosis. In this situation the liver may be completely normal and healthy.
Scarring in the liver due to cirrhosis. Cirrhosis occurs as liver cells are damaged and die. They are then replaced with scar tissue (fibrosis).
Occasionally, a blockage of the hepatic vein draining blood from the liver can cause increased pressure in the portal vein, but this is not common in children.
The increased pressure in the affected blood vessels can affect other areas of the body including:
An enlarged spleen (splenomegaly):
The spleen is connected to the liver by a vein which joins the portal vein. This means that if there is high pressure in the portal vein, this may affect the spleen, causing it to enlarge.
The spleen’s job is to break down old blood cells. When it gets larger it removes more blood cells than it should. This includes a type of blood cell called platelets which help to stop bleeding. Not having enough platelets can lead to bruising and nosebleeds.
Ascites can be the reason for a child’s tummy suddenly getting bigger. Ascites is a collection of fluid in the tummy (abdomen). Portal hypertension can cause this because the high pressure in the blood vessels pushes fluid out of these blood vessels into the space between the organs.
Abdominal swelling can also be caused by the spleen and liver getting larger. If this is the cause the tummy is not normally as swollen as it is with ascites.
Noticeable veins under the skin of the tummy:
Veins can appear under the skin of the tummy because it is swollen. They can also appear because blood returning to the heart through the portal vein is blocked. The blood is then forced out of its usual route and forms new veins to get around the blockage. When this happens near the surface of the skin the veins may be seen.
As well as veins becoming visible over the surface of the tummy, other veins can become enlarged, especially in the digestive tract (the oesophagus, stomach and intestine). These are called varices. They look similar to varicose veins which people can have in their legs. When these occur in the food pipe (oesophagus) or in the stomach they can bleed as they have thin walls.
Signs of bleeding:
Varices have thin walls and may bleed. Bleeding can cause tiredness and can cause a child to feel short of breath. It can also cause a pale appearance. Blood might appear when a child is sick (vomits) and may appear in their stool (poo) which can be blood stained or black.
If there is a large bleed a child may have tummy pain, be dizzy and may collapse. Whatever the sign of bleeding, seek emergency medical advice by calling 999.
Diarrhoea and poor weight gain:
The blood vessels which line the intestine can become swollen as blood flows through them under a high pressure. This can lead to fewer nutrients and less fluid being absorbed from food travelling through the intestine.
A general physical examination
An ultrasound scan:
This is the same scan pregnant women have. It is used to measure the size of the liver and the spleen. If the spleen is larger than expected this may suggest the child has portal hypertension.
The scan can also be used to check the direction of the blood flow in the veins around the liver.
A flexible tube, called an endoscope, is passed into the mouth, down the oesophagus, through the stomach and the intestine. This allows the doctor to look directly at the lining of the digestive tract to see if there are varices.
This is usually done under general anaesthetic (where the child is completely asleep) or under sedation (where the child has drugs to make them sleepy and relaxed). ColonoscopyThis is similar to the endoscopy but the tube is passed up the anus to examine the lower intestine. It is often not needed to make a diagnosis.
Your child will have blood taken and the levels of platelets will be reviewed. There are some cases where a child has portal hypertension without having a known liver disease. These children may need more tests including:
Under anaesthetic, a thin tube is passed into a blood vessel in the groin and a special dye is injected into this. X-rays are then taken to give a ‘map’ of the child’s portal vein and its branches.
Magnetic resonance imaging (MRI):
The child will have a cannula or drip inserted, which is used to pass dye into the vein.
The child then lies on a bed in a long circular tube whilst computerised pictures are taken.Sedation or anaesthetic is not normally required provided the child is able to stay still, but in young children an anaesthetic may be needed.
Treatment may be needed if there is an underlying liver condition which has caused the portal hypertension.
If portal hypertension leads to varices which bleed, treatment of the varices will be required.The main treatment for varices is called banding.
When portal hypertension is confirmed, an endoscopy will be planned to assess whether varices are present. The timing of this will depend on the age and size of the child, as well as any complications that are known to be present, such as enlarged spleen and low platelet count.
During the endoscopy, if varices are present, the doctors will grade them according to their size. If necessary, the varices will be treated at the time of the endoscopy. Banding involves placing a medical rubber band over the affected blood vessels (the varices).
This causes the blood in the varices to clot or thrombose. This means that blood cannot flow through the varices which reduces the risk of bleeding. The elastic band will fall off and may be seen in a child’s stool (poo) after a few days, although it is tiny and may not be noticed.Banding can be done urgently when your child is an inpatient, or it can be a planned or procedure. Repeated endoscopies are usually needed to improve the varices, usually with intervals of weeks or months between each session. SclerotherapyAnother treatment for varices is called sclerotherapy. This is performed when banding may not be possible, for example in a very small child.An endoscope is passed down the oesophagus, a needle is passed through the endoscope into or next to the varices and a chemical is injected. The chemical causes the varices to clot and close off.
These veins help the blood flow back into the main circulation via a new route so the blood pressure in the portal circulation is lowered.Bleeding is more likely if varices form in places where the walls of veins are thin, including the oesophagus and the stomach.If the varices have inflamed the lining of either the oesophagus or the stomach then a medicine will be given to protect the lining and help it to heal
The team at the hospital should be told that the child has a diagnosis of portal hypertension and be given a description of the symptoms. The medical team will give families a letter to carry with them to show the emergency doctor.
In hospital the child will be assessed and treated if needed. Some bleeds are very small and don’t require the child to stay in hospital, but often it will be recommended that your child remains in hospital for observation.
The hospital team caring for your child may:
- Monitor the child’s blood pressure and pulse
- Observe the vomiting/colour of stools
- Find out how much blood has been lost
- Give the child fluid/blood through a drip
- Give medicines to stop the bleeding
- Perform an endoscopy to look at the varices which are bleeding
- Treat the varices by putting rubber bands around them (banding) or by injecting the varices with a chemical to stop the bleeding (sclerotherapy)
-Contact your liver team
Do children with portal hypertension need to take special precautions?
Medicines such as aspirin and ibuprofen should be avoided as they can make bleeding in the gut more likely. Paracetamol (Calpol) is a safer alternative.It is important to be aware of the potential issues which could occur e.g. bleeding. It is vital that all carers and teachers are aware of what to look for and what to do if they notice any signs that there may be a problem.
If the spleen is enlarged there is a higher chance of it being damaged if it receives a hard blow so children may be advised to avoid activities where they may receive a blow to the abdomen e.g. some contact sports such as kick boxing and rugby. Most physical activity however is to be actively encouraged, and children should participate in PE at school.
It’s important not to limit activities unnecessarily and the child’s medical team will be able to provide specific advice on a case by case basis.If a child with portal hypertension is travelling/flying it’s important that their medical team are informed as the child may need treatment before going.
Ascites can be caused by:
Less albumin (a protein) being made by the liver
Albumin helps to keep fluid within blood vessels. If the liver produces less albumin, its levels fall and fluid leaks out of blood vessels and collects in cavities and tissues in the body. When the fluid collects in the abdomen it is known as ascites.The fluid can also leak into the space between the lungs and the chest wall which is known as pleural effusion.
Increased pressure within blood vessels
As described previously, portal hypertension raises the blood pressure in the veins and around abdominal organs which leads to fluid leaking into the abdomen.
Salt being retained in the body
This can contribute to the build-up of fluid in the tissues and cavities.
Shiny, tight skin over the swollen tummy
Prominent veins visible beneath the skin on the tummy
Quick weight gain which is not due to normal growth
Shortness of breath
Loss of appetite (eating less)
How is a diagnosis made?
A diagnosis can be made by the doctor examining the child or by using an ultrasound scan.
What are the possible complications of ascites?
Poor nutritional progress
The fluid in the abdomen can make children feel full very easily. Children may eat smaller portions and can vomit due to limited space in the abdomen. A dietician will be able to advise and support you. CLDF has a leaflet on nutrition with further information.
The fluid in the abdomen can become infected by bacteria. This is called spontaneous bacterial peritonitis.Any fever with pain or tenderness over the abdomen with ascites should be reported to the medical team immediately. This is usually treated with intravenous antibiotics.
With small children and toddlers their movement can be restricted by the ascites due to their enlarged tummies so they may not develop as quickly as expected. A physiotherapist will be able to advise on exercises to encourage developmental progress.
Ascites can sometimes make breathing difficult as there is less room for the lungs to expand. It’s important to inform the medical team if this is a problem. Sitting in a more upright position can help as well as using extra pillows when in bed.
How is ascites treated?
There are different treatments are available to try and deal with ascites, although these won’t cure it.
A diuretic may be prescribed. This is a medication which helps the body to get rid of extra fluid and will lead to needing to urinate (wee) more often. A diuretic called spironolactone is commonly used. Children taking diuretics have an increased risk of becoming dehydrated (not having enough fluid) if they have vomiting or diarrhoea. This should be reported to their doctor, as well as the fact that they are on diuretics and have liver disease.
Nutrition and diet
A dietician may advise changes to a child’s diet. It’s important to ensure the diet has enough nutrients and energy to grow and to reduce salt. Too much salt can make ascites worse so it’s important not to add salt to food and to avoid salty foods such as crisps.
In some cases a reduction in the amount of fluid being drunk may be advised. This must not be done without medical advice and a dietician and doctor will advise if this is necessary.
The albumin in the blood stream is very low it might be necessary to give a child albumin. This is done through a drip.
Drainage of excess fluid (ascitic tap)
A thin needle is passed into the cavity in the abdomen. This is then attached either to a drain or to a syringe. A local anaesthetic is used to numb the area where the needle will be placed. This procedure is done using an ultrasound scan for guidance.