Annular Pancreas

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Annular Pancreas (AP) is a rare birth defect affecting children from all over the world. This article deals with its causes, symptoms, ways of prevention and treatment.

Annular Pancreas Definition

Under normal circumstances, the pancreas is located next to the duodenum but does not encircle it. AP causes the duodenum of the patient to get surrounded by a pancreatic tissue ring continuous with its head. The abnormality has also been reported in adults. The disorder is characterized by constriction of the duodenum and blockage of the passing of food to the intestines.

AP is a rare condition mainly occurring in newborns.

Annular Pancreas Incidence

According to various studies, AP is estimated to have an incidence of approximately 1 out of every 12,000 to 15,000 births. The exact incidence rate have not been calculated yet because of the fact that in most cases, the symptoms do not occur until the patients reach adulthood and many cases remain asymptomatic for the entire life of the sufferers.

Annular Pancreas Causes

It is a congenital condition, meaning it is present at birth of patients. It is caused by certain genetic changes that take place during the fetal development. In most cases, it is caused by an abnormal embryological development. However, its pathophysiology is still not clearly known.

The disorder can occur due to the development of a bifid ventral bud circling the duodenum. The pancreatic ring grows from the sites where bifid ventral bud fuses with dorsal pancreatic bud. Annular Pancreas can also occur if the ventral bud does not rotate fully and remains at the right side or the dorsal bud turns into the wrong direction, leaving the duodenum surrounded by pancreatic tissues. This can cause Pancreatitis – an inflammatory condition which causes blockage of duodenum and leads to Annular Pancreas.

AP is often associated with other congenital disorders, including Down Syndrome as well as other conditions like:

Tracheoesophageal fistula

It is a fistula or abnormal connection between the trachea and esophagus.

Intestinal atresia

It is an incomplete formation of a certain part of the intestinal tract of patients.

Pancreas divisum

It is a type of birth defect resulting in failure of the pancreatic ducts to join together.

Polyhydramnios

It refers to an excessive production of amniotic fluid in pregnant women.

Annular Pancreas Symptoms

The symptoms of the disease occur due to the pressure exerted over the small intestine by the pancreas. Sometimes, the tissue surrounding the pancreas is too small to cause any detectable symptoms. Partial obstruction of the duodenum usually does not cause any evident symptoms until the patients become older. Approximately 50% of the children with the disorder remain asymptomatic.

In comparatively serious cases, the pancreatic ring around the small intestine leads to a blockage which makes it difficult for patients to eat normally. Infants with AP can have the following symptoms:

  • Excessive crying
  • Difficulty feeding
  • Spitting up more than usual

In some cases, the symptoms do no develop until a patient reaches adulthood. These signs include:

  • Fullness after eating
  • Nausea
  • Vomiting

This condition rarely causes the symptom of bilious vomiting after feeding. It more commonly occurs in newborns with Duodenal Atresia and helps in its differential diagnosis.

Annular Pancreas Prevention

There is currently no measure to keep the pancreatic disorder form occurring. However, taking the following measures during pregnancy can decrease the chances of having a child with the disorder:

Maintaining diet

It is advisable for pregnant women to maintain a diet consisting of whole grains, fruits and vegetables.

Regular prenatal checkups

One should go for regular prenatal checkups during pregnancy.

Giving up smoking

It is also important to give up smoking during this time.

Non-consumption of alcohol

Pregnant women should not consume alcohol as it is harmful for the fetus.

Using only prescribed drugs

It is advisable not to use any drugs unless they are prescribed by a doctor.

Annular Pancreas Diagnosis

There are various diagnostic tests that help to detect the presence of AP in an individual. Doctors perform a thorough physical examination and study the medical history of a sufferer, including the underlying congenital problems he or she may have experienced in the past. One or more of the following tests may be required for confirming the diagnosis:

  • Abdominal ultrasound
  • X-ray of abdomen
  • CT (computed tomography) scan
  • Small bowel series
  • Upper GI (gastrointestinal) series

Apart from the above mentioned exams, other imaging tests such as the MRI (magnetic resonance imaging) and MRCP (magnetic resonance cholangiopancreatography) can also be used during this diagnosis.

Prenatal ultrasound during the second trimester can help to diagnose AP by detecting the presence of the double bubble sign.

Annular Pancreas Differential Diagnosis

The differential diagnosis includes taking into account various types of duodenal stenosis that can result in symptoms similar to AP. Other conditions that should be ruled out include:

  • Duodenal neoplasm
  • Pancreatic neoplasm
  • Duodenitis
  • Duodenal Atresia
  • Duplication cysts of duodenum

Annular Pancreas Treatment and Management

Almost all cases of this condition need to be treated surgically. The main object of treatment is to get rid of the blockage so that the small intestine can function properly. Generally, it is not recommended to remove the pancreatic tissue from the duodenum as it can lead to damage of the pancreas.

Duodenoduodenostomy is a surgical procedure that is most commonly used for the treatment of AP. In this procedure, a tiny camera is inserted into the abdominal cavity of patients for inspecting the stomach as well as the small intestine. A number of small incisions are then made in the lower region of abdomen to manipulate certain surgical tools for severing the stomach from duodenum, bypassing the area affected by pancreas and connecting the involved part to the next intestinal section.

Annular Pancreas Prognosis

The long-term prognosis of the disorder is generally positive, but depends on the age of the patient. The Duodenoduodenostomy surgery is associated with a considerable success rate with most newborns and adults achieving complete recovery within a few months. Infants diagnosed with the condition usually have excellent long-term prognosis. However, adults diagnosed with AP are more at risk of developing certain complications.

Annular Pancreas Complications

AP can give rise to the following complications:

Obstructive Jaundice

It is a condition causing obstruction of the bile flow.

Pancreatitis

It is characterized by an inflammation of the pancreas.

Peptic ulcer

It is a disorder leading to a defect in the first section of the intestine or the stomach lining.

Intestinal perforation

It is a hole in the bowel.

Peritonitis

It is marked by an inflammation of tissues lining the inner wall of abdomen.

Additionally, adults with AP have an increased risk of developing certain forms of cancer such as pancreatic cancer and biliary tract cancer.

Annular Pancreas is a curable condition and requires early medical attention. Proper treatment allows affected children to lead a normal life and take part in all regular activities.

References:

http://www.healthline.com/health/annular-pancreas

http://www.umm.edu/ency/article/001142all.htm

http://www.iamunwell.com/Diseases-Alphabet-A/annular-pancreas.html

http://www.nlm.nih.gov/medlineplus/ency/article/001142.htm

http://health.nytimes.com/health/guides/disease/annular-pancreas/overview.html

http://www.wisegeek.com/what-is-an-annular-pancreas.htm

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