Choledochal Cyst

Choledochal cysts are abnormal vesicles that arise only rarely but can have fatal consequences in adults. Read and know more about the types, symptoms, diagnosis and treatment of these sac-like growths.

Choledochal cyst Definition

Choledochal cyst is a rare sort of neonatal disorder which affects the hepatic or bile duct of the liver. The term “neonatal” means newborn which clearly indicates that it is a congenital disease and usually occurs in the first 12 months of a child’s life. However, it can occur in adults as well and can be even more severe.

Epidemiology of Choledochal Cyst

These cysts are very uncommon and affect 1% of the population, females being more prone to them than males. The sacs occur mostly in babies of Southeast Asia, especially those born in Japan.

Choledochal Cyst Classification

Choledochal Cysts Pictures
Picture 1 – Choledochal Cysts

The cysts have been classified into five main types, based on their location and distension. These are:

Type I

It refers to a spindle shaped expansion of the common hepatic duct and common bile duct. It occurs in the extrahepatic bile duct i.e. the part of duct located outside the liver. It is further subdivided into 3 types

  • Type 1A is saccular (sac like) dilation and affects almost the entire extrahepatic bile duct.
  • Type 1B is saccular dilation and affects a small region of the extrahepatic bile duct.
  • Type 1C is fusiform (spindle shape) dilation and affects almost the entire extrahepatic bile duct.

Type I is the most common Choledochal cyst.

Type II

It is an isolated sac-shaped duct that protrudes out of the side wall of the CBD. It is also sometimes attached to the external wall of the bile duct by a support.

Type III

Also referred to as Choledochocele, it arises from the dilated duodenal section of the CBD or the region where the pancreatic duct runs into.

Type IV

It occurs in the intrahepatic bile duct (the part of duct located inside the liver) and extrahepatic bile duct. It is further classified into Type IVa and Type IVb. Type IVa is marked by more than one dilatation of the intrahepatic bile duct as well as extrahepatic biliary tree. Type IVb is characterized by more than one dilatation that only involves the extrahepatic bile ducts.

Type V

Also known as Caroli’s Disease, it is characterized by an expansion of the hepatic ducts located within the liver. In this type, multiple dilations are only limited to the intrahepatic bile duct.

Choledochal Cyst Symptoms

The bile duct is the most vital medium of transportation of bile produced by the liver cells to the gall bladder and duodenum. It helps the digestive process in the body. Dilation or inflammation of cysts in the bile duct leads to an abnormal enlargement of the duct which invites a series of other chronic liver disorders.

Choledochal Cyst in Children

Choledochal Cysts are congenital, meaning they are present at birth. Such type of a cyst occurs while a baby is in the developmental stage – even before they are born. These are usually diagnosed during ultrasound exams conducted at the time of birth. Many babies with such cysts are found to exhibit symptoms, such as jaundice, soon after they have been born. Others do not display any problems until they are aged 2 years or more. Typically, babies with such vesicles also exhibit other problems like:

  • Abdominal inflammation
  • Peritonitis
  • Cholangitis
  • Sporadic abdominal pain

In babies suffering from acute abdominal pain or jaundice right after birth an ultrasound examination often reveals a dilated bile duct. In some cases, other diagnostic tests like MRCP (Magnetic Resonance Cholangio-Pancreatography) and ERCP (Endoscopic Retrograde Cholangio-Pancreatography) may be carried out to get more information.

Choledochal Cysts and Genetics

The development of these abnormal vesicles is often supposed to be associated with genetics. The chief reasons why heredity is believed to be a causative factor are:

  • Girls are found to be 3-4 times likelier to have these cysts than boys.
  • Babies of Eastern and South-east Asian descent are likelier to have these vesicles than babies from other regional backgrounds.

Parents with a baby having these vesicles often wonder whether they can have another child with similar problems. Medical research does not offer any support for this. It is believed that factors apart from genes are also responsible for the occurrence.

Choledochal Cyst Complications

In children, it leads to enlargement of liver or formation of abdominal mass due to the accumulation of bile which gets obstructed because of the blockage in the duct prior to the swelling of the cysts.

If not treated it may lead to complications like

  • Liver Cirrhosis, where bruising of the liver cells takes place and is the last stage of chronic liver damage
  • Portal Hypertension, where high blood pressure occurs inside the liver due to blockage of veins
  • Ascites, where abdominal fluid accumulation takes place and is a consequence of cirrhosis
  • Cystic cancer where the cyst turns malignant and spreads in the entire liver region and may turn lethal.

In adults, formation of gall stones takes place. This may lead to:

  • Acute abdominal pain due to the accumulation of fluid.
  • Recurrent attacks of jaundice due to accumulation of bilirubin in the liver as well in the other areas of the body like skin and eyes.
  • Pancreatitis where there is inflammation of the pancreas due to release of some other enzyme triggered by the cyst.
  • Cholangitis where the bile duct gets subjected to bacterial attack and may even infect the liver.
  • Nausea where the patients always undego uneasiness which often triggers vomiting sensation.

Choledochal Cyst Diagnosis

Diagnosis is simpler if the symptoms are identified and understood. Some of the main diagnostic tests for this condition are:

Hyperbilirubinemia

The test helps detect the level of bilirubin in blood. If it is higher than normal range, it can be indicative of an abnormal condition in the liver.

Ultrasonography

An ultrasound-based diagnostic imaging technique is used for visualizing the choledochal cyst in the bile duct.

Cholangiography

The process involves oral administration or injection of some form of contrasting dye to the patient, followed by a regular x-ray imaging or Magnetic Resonance Imaging (MRI) to detect the bilirubin content in the liver. If the amount of bilirubin is in excess then the liver region appears darker than any other part in the abdomen which indicates some kind of abnormality.

Choledochal Cyst Treatment

A surgical removal of the cyst is usually done followed by suturing of the ducts to the intestine in order to let the bile flow out of the ducts and carry out the normal function. Cholangitis can occur as a side effect.Laparoscopic surgery is more advisable where a complete excision of cyst is done and a small section of intestine is raised up and sutured to the bile duct in order to regulate and maintain the flow of bile into the intestine.

Choledochal Cyst Surgery

Surgery is the most preferred mode of treatment for these vesicles. Doctors often recommend excision of complete cystic tissue due to high risk of cancerous degeneration and recurrent Cholangitis. The standard operative procedure is a choledochal or hepato-jejunostomy along with a Roux-en Y-loop. It helps in complete excision of the cyst as well as biliary tree reconstruction.  The outcome of surgery is good for patients who undergo treatment for type I, II, III and IV cysts and do not have portal hypertension or preexisting cirrhosis.

However, good prognosis ultimately depends on long-term care and follow-up of patients. Follow-up, usually carried out with ultrasound tests, help ensure that bile drainage into the intestine remains uninterrupted. It also helps make sure that postoperative Cholangitis cases thoroughly investigated and properly treated. If no complications are present, patients are likely to have a normal lifespan.

Choledochal Cyst Prognosis

In its initial stage this type of a cyst is benign. However, it might get fatal as it reaches a mature stage. Post surgery, a regular follow up of the patient is a must as there might be a possibility of Cholangitis or Cholangiocarcinoma.

Choledochal Cyst Duration

The vesicle is clearly visible by 2 or 3 years of age. At times, however, it cannot be detected until the stage of adulthood approaches.

Choledochal Cyst Prevention

This is a congenital disease and cannot be prevented. So far, no valid techniques have been found to prevent the development of these cysts.

References:

http://emedicine.medscape.com/article/172099-overview

http://www.medicinenet.com/choledochal_cysts/article.htm

http://childrenshospital.org/az/Site714/mainpageS714P0.html

http://www.patient.co.uk/doctor/Choledochal-Cysts.htm

By    Last updated May 3rd, 2012

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