What is cystic disease of the liver?
The overwhelming majority of cystic disease iscaused by simple cysts. There are also inherited disorders that cause cysts, including polycystic liverdisease, congenital hepatic fibrosis and Caroli’s syndrome. Although rare in the UK, hydatid cystsare caused by a parasitic infection.
The bile ducts in the liver are like the branches ofa tree that come together just below the stomach.This is known as the biliary tree, sometimes calledthe biliary system or biliary tract. A side branch of the biliary tree leads to the gallbladder, the organthat stores bile. Gallbladder disease involving the biliary tree is more common than cystic disease.
Cysts affecting the biliary tree belong to a groupof diseases caused by congenital bile ductabnormality and are usually inherited. These cystscan create problems by:
placing pressure on surrounding organs andbody tissue as they become enlarged
causing inflammation of the bile ducts, knownas cholangitis
- causing increased blood pressure in the portalvein, known as portal hypertension.
Different types of liver cysts
Simple liver cysts
Simple cysts arise from a malformation of yourbile ducts. In rare cases, they can cause bile duct obstruction, secondary infection or may rupture.Some may require surgical drainage.
Simple cysts are not inherited and unrelated topolycystic liver disease in whichmany more cysts are present. They are estimatedto affect between 1% and 2.5% of the population.They affect all ages, but occur more frequently inthe population as age increases.
Simple cysts usually have no symptoms. Largercysts may occasionally cause some dull pain and/or swelling in the upper right hand side of yourabdomen, an area referred to as the ‘right upperquadrant’. Jaundice (yellowing of the skin andwhites of the eyes), which is often caused by bileduct obstruction, is rare.
To diagnose simple liver cysts medical staff mayrecord your medical history and carry out aphysical examination. An ultrasound or CT scan ofyour abdomen may also be carried out. Simple liver cysts generally do not require treatmentunless they become large enough to cause pain.
If required, to reduce their size, doctors can remove the fluidfrom the cyst. They do this by inserting a needle through the skin under X-ray guidance, andwithdrawing (aspirating) the fluid. However, the fluidwill usually refill the cyst. To help stop this, afterthe fluid has been taken out, doctors may injecta substance into the cyst to help stick the wallstogether. This substance is called a sclerosant.A similar technique involves removing part of the wallof the cyst, called laparoscopic de-roofing.
Polycystic liver disease (PLD)
Adult polycystic liver disease is an inheriteddisorder where many cysts of various sizes develop throughout your liver and is associated withcongenital hepatic fibrosis. Both conditions have in common a growth ofnumerous abnormally shaped (malformed) bileducts, known as ductal plate malformation. PLDmay occur with polycystic kidney disease (PKD)or alone but is less common and milder than thekidney form.
The tendency to form multiple cysts is probablypresent at birth, but cysts usually do not becomelarger and cause problems until you are an adult.
Cysts can be very small, perhaps no larger thana pinhead, but can grow up to 10cm. Similarly,your liver can remain its normal size or becomeheavily enlarged.Your liver should continue to function effectively inPLD and the disease is not considered to shortenyour life expectancy. PLD becomes more common with age but is rare,affecting much less than 1% of the population.
Women tend to be more affected as the size andincrease of cysts is thought to be linked to levelsof oestrogen.
Polycystic liver disease is first noticed during puberty,with symptoms becoming more noticeable as youenter your thirties. Most people are diagnosed intheir forties and fi fties. PLD is often without clear symptoms, but swollen, painful abdomen and anenlarged and hardened liver (hepatomegaly) areusually associated with the condition. In many casespolycystic liver disease is discovered by accidentor noticed during diagnosis of kidney disease. Themajority of people with polycystic kidney disease will also have PLD.
Laboratory tests such as liver and renal functiontests may be used to diagnose PLD. Liver function tests (LFTs) are used to indicate whether your liver isinflamed (hepatitis), damaged or not working properly.They measure levels of certain enzyme and proteinsubstances in your blood that may alter when liverdamage is present. Doctors will also use imaging testssuch as ultrasound, CT or MRI scan and a special X-rayof the kidney (intravenous pyelogram).
Cysts rarely require treatment. If necessary,laparoscopic de-roofing can be helpful for reducinglarger, uncomfortable cysts. In rare cases of severePLD, where multiple cysts cause the liver to become massively enlarged and very painful (leading to othercomplications), a liver transplant may be required.This is usually only recommended if your quality of lifehas become very poor and other treatments are nolonger helpful.
Choledochal cysts
There are different types of choledochal cysts.They are categorised by their size and where theyare found. They affect the main trunk of the biliarytree, known as the common bile duct, causing itto become unusually enlarged. This is called cysticdilatation and probably occurs at time of birth. Itleads to an abnormal junction between the commonbile duct and the pancreatic duct (anomalouspancreatobiliary junction, or APBJ).
Usually by the age of two or three, but sometimesnot until you have reached adulthood, the duct may form a cyst. This prevents the bile from reaching theintestine. Bile backs up into the liver, causing you tobecome jaundiced. Inflammation and weakening ofthe bile duct walls will follow.
In childhood this may lead to pancreatitis(inflammation of the pancreas), cholangitis and liverdamage. The most worrying complication may becholangiocarcinoma, a rare type of cancer thatdevelops in cells lining the bile ducts in the liver.
Choledochal cysts are extremely rare. Thecondition affects females more than males andoccurs more commonly in Southeast Asia, withmore than 30% of reported cases occurring inJapan. The majority of choledochal cysts are seenin childhood, although some people may not showsymptoms until they are adults. Symptoms are jaundice, caused by the reducedamount of bile draining from the abnormal bile duct,and abdominal pains. Pain may be increased if thebile building up in the liver becomes infected. In some cases the cyst can be felt by the doctor whenexamining your abdomen.
The diagnosis of choledochal cysts is not difficultonce the condition is suspected. Cysts can be confirmed by using imaging equipment suchas ultrasound, MRI or magnetic resonance cholangiopancreatography (MRCP), endoscopicretrograde cholangio-pancreatography (ERCP)and CT.
During an ERCP, the endoscope is passed into theduodenum and contrast medium is injected backup into the bile ducts. This can be visualised withX-ray screening allowing the gastroenterologist tosee the outline of your biliary tree.ERCP is an endoscopic procedure which,although invasive, is valuable in examining bothyour biliary and your pancreatic structures. It canidentify problems with the biliary tree, cystic ductobstruction, gallstones, narrowings and tumours.
If the condition is not correctly diagnosed theblockage of bile may result in scarring (fi brosis) ofyour liver. Extensive scarring may lead to cirrhosis.If you are diagnosed as an adult, inflammationand damage to the bile ducts may have beenoccurring for many years.
Choledochal cysts are treated by surgical removalof the abnormal segment of the bile duct and reconstruction of the biliary tree so that bile travelsback into the intestine.
Caroli's syndrome
Caroli’s disease and Caroli’s syndrome are biliarytree disorders in which small cysts alternate with narrowed segments of the bile ducts. Theseabnormalities may be present throughout the liver,or limited to a small area. They are more commonin adults and more likely to occur in women.
Caroli’s disease, which occurs in the main bileducts, is less common than Caroli’s syndromealthough both are very rare. In Caroli’s syndromethe small bile ducts are also malformed andcongenital hepatic fibrosis occurs.
Caroli’s syndrome is generally inherited, whereasCaroli’s disease is not. As with congenital hepatic fibrosis, Caroli’s syndrome is often associatedwith autosomal recessive polycystic kidneydisease (ARPKD).
People with Caroli’s disease and Caroli’ssyndrome may have cholangitis, portalhypertension and, as with people who havecholedochal cysts, are at much higher risk ofdeveloping cholangiocarcinoma.
The symptoms are usually abdominal pain and,very rarely, jaundice. Complications from portalhypertension may cause vomiting of blood(haematemesis) and blood in your faeces (maelena).Bleeding comes from burst or ruptured varices.If the bile becomes infected, you may developfever, abdominal pain and, rarely, jaundice. Thiscomplication can first appear in childhood or maynot occur until middle age.
Doctors will be looking for bile duct abnormalitiesand evidence of fibrosis. LFTs, imaging and liver biopsy may all be used in diagnosis. Radiologists will scan the bile ducts usingultrasound, CT and MRCP. ERCP and anotherinvasive technique called percutaneoustranshepatic cholangiography (PTC) may also beused. With PTC, a thin needle is passed throughyour skin and through the liver into a bile duct.A dye is injected so that the biliary tree becomesoutlined on X-ray. This picture will show anynarrowing or blockages. If severe cholangitis is suspected, a liver biopsymay also be carried out.
Treatment may be required if you have recurrent orsevere cholangitis. This can involve reconstructive surgery to improve the flow of bile. If you havedeveloped gallstones, these may be removed byan ERCP procedure.A medication made from naturally occurring bileacids called ursodeoxycholic acid (URSO) mayalso be given to soothe any complications arisingfrom gallstones.
Congenital hepatic fibrosis (CHF)
Congenital hepatic fibrosis is an inherited diseasethat affects both your liver and your kidneys. CHFcauses scarring and hardening of the liver, whichmakes it more difficult for the blood to flow throughit. This causes a condition called portal hypertension,where there is increased pressure in the veins thatcarry blood to the liver. Bleeding oesophagealvarices – small, protruding veins that line your gullet(oesophagus) – are an early sign of this condition.
If you have CHF your kidney function may also beaffected. Some scientists believe that CHF and another condition called autosomal recessivepolycystic kidney disease (ARPKD) are part of thesame disorder.
Both CHF and ARPKD are very rare, affectingaround one person in 20,000 and symptoms occurmore in newborns and young children.Symptoms of CHF may be apparent from earlychildhood. These may include abdominal pain.Your kidneys and spleen may also be enlarged.Complications from portal hypertension may causebleeding in the stomach, vomiting blood andblood in your faeces (from oesophageal varices).This condition is usually diagnosed in childhood,either because you have an enlarged liver or becauseof bleeding varices. In some people the diagnosis isnot made until adult life. In addition to liver functiontests, diagnosis is made by carrying out:
an ultrasound scan of your liver and kidneys
a CT scan of your abdomen
an X-ray of blood vessels (angiography)
an endoscopy to detect varices
a liver biopsy.
CHF differs from cirrhosis because your livercells remain able to function. There is no specifictreatment for the condition but many people requirere-routing of blood from the intestines. This is knownas a ‘shunt’ operation and is carried out to preventmore intestinal bleeding. A metal or plastic tube(stent) is used to join two veins in order to changethe direction of blood fl ow. It is usually done bya radiologist with the help of ultrasound or otherimaging equipment to guide them. This procedurewill mean at least a day or two in hospital.
Bleeding oesophageal varices can be treated duringendoscopy. This is a procedure in which a long,flexible fibre optic tube with a tiny camera on the end(endoscope) is passed into your gullet after you havebeen sedated.
The bleeding is often treated using a technique calledbanding, often carried out as day surgery. Bandingis where a vein is sucked into a small chamberattached at the end of the endoscope and a smallband is placed around its base (ligation).
Complications from bleeding varices are life threateningand early diagnosis is important.When these procedures are effective, without othercomplications, the prognosis for people with CHFis usually good.
Hyatid cysts
This type of disease is a parasitic infestation by atapeworm known as ‘echinococcus granulosus’.This parasite, which lives mainly in dogs, entersyour body as larvae. This is likely to happen whenyou handle an infested animal or eat food or drinkwater contaminated by its faeces. The larvae travelin the bloodstream and lodge in organs to formcysts. The liver is most commonly affected (70%of hydatid cysts form there), followed by the lungs,brain and bones.
The cysts become larger and in some cases forma mass. This can take decades, and not all cystsare active. Growing cysts can cause damage toyour body tissues either directly or by affectingthe flow of blood. They can also rupture or leak,possibly leading to allergic reaction and shock(anaphylaxis). If the rupture affects biliary ducts,cholangitis may follow. More seriously, secondaryinfection can occur if this happens in your lungs. Aruptured cyst will also cause the disease to spreadfurther in your body.
Hydatid cysts are very rare in the UK and are morelikely to be contracted abroad where there hasbeen contact with sheep dogs and other animals.These areas are more commonly southernEurope, the Middle East, Australia, New Zealandand South America.
A related parasite, echinococcus multilocularis, isfound in the northern hemisphere. It lives in wildfoxes and is passed on through contact withrodents. It enters the human body in the same wayas echinococcus granulocus but the cyst behavesmore like a cancerous tumour.
Both parasites can cause severe liver disease butare very rare. They are estimated to affect only one person in 100,000 in the UK. Symptoms may be at first general and can benon-specific. They are generally caused bypressure from the size of the cysts. Possiblesymptoms may include:
abdominal pain and/or swelling and tenderness
coughing
skin rashes
itching (pruritus)
jaundice
Because the parasite grows slowly in your body it israrely diagnosed during childhood or adolescence unless your brain is affected. Diagnosis of hydatiddisease is usually reached by blood tests and imaging tests.
Liver function tests are used, together with a testmainly in immunology to detect the presenceof antigens or antibodies, known as theenzyme-linked immunosorbent assay (ELISA).Antigens are invading or foreign proteins, andantibodies are the proteins your body producesto defend against them.
CT and ultrasound scans are most commonlyused to show single or multiple cysts. MRI scansmay be used to provide greater detail to helpdoctors decide whether cysts are active, inactiveor something in between (transitional). ERCP maybe used to show cysts in the bile ducts.
Drugs are usually used first in the treatment ofhydatid disease to help prevent any spread ofthe disease although surgery is still required inmany cases. The fi rst line drug treatments arealbendazole and mebendazole. These drugs aregiven in oral form and work by being absorbedthrough the cyst’s membrane to affect its growth.You will have to take these drugs for three months.Another drug, praziquantel, can be given over 14days and is now sometimes used in combinationwith albendazole and mebendazole.
Between a third and half of cysts treated with drugsmay grow smaller or disappear.If surgery is required, the aim is usually to removethe cyst completely. This can be complicated,particularly where there has been secondaryinfection from the cyst, and in certain cases maycarry significant risk of mortality.