Approach to Chronic Abdominal Pain in Children

Children with chronic abdominal pain account for 5% of all outpatient visits in the pediatric age group. Up to one-third of all children have this complaint, yet less than 10% of these children will have an identifiable organic etiology for their pain. These issues can have great impact on the functioning of the entire family, often causing work absence for the parents, excessive school absence for the child, and feelings of helplessness for the entire family unit.

Definition
Chronic abdominal pain is defined as at least 3 episodes occurring within a 3-month time-span that interferes with normal activity.

Incidence
It is slightly more common in girls than in boys, and usually occurs between the ages of 5 and 12 years. There is an increased incidence of recurrent abdominal pain in the families of these children.

History
The evaluation of a child with chronic abdominal complaints—or for that matter, any problem at all—starts with a comprehensive history. This should start with an interview of the child, as long as he is of the developmental stage in which he can respond to questions with verbal answers. Once exhausting the information available from the child, the parent or caretaker is interviewed. This allows the child to become part of the process, rather than feeling like an excluded object, and generally ensures that you will be able to interview the parent without as much interruption when the child has been asked to speak first.

Two major questions that help separate functional gastrointestinal complaints from disease-based problems are:

1. Does the pain wake you up out of sleep in the middle of the night?
2. Can you point with one finger to the spot that hurts?

As a general rule, children who spontaneously wake up out of deep sleep with abdominal symptoms have an organic basis for their complaint, while children with functional pain may have trouble falling asleep, but generally sleep soundly without interruption once they do. Similarly, children who cannot identify a specific site of pain, or who point exclusively to the periumbilical region when asked to identify a spot, will usually have a functional basis for their complaint. Those who can identify a specific quadrant or radiation pattern of their pain will more commonly have an underlying disease process.

In addition to the above, establishing a pattern of the pain occurrence is most helpful in deciding on an etiology. Questions that help establish specific patterns, are listed below:

• Does the child wake up in the morning with pain?
• Does the pain feel worse or better with eating? If worse, how soon after eating does it occur, and how long does it last?
• Are there any foods that make the pain better or worsen it?
• Is there any associated dysphasia/odynophagia (difficulty/pain with swallowing)?
• Is there any nausea or vomiting?
• What time does the child go to bed/fall asleep/wake up in the morning?
• What is the pattern/consistency/completeness of evacuation of bowel movements?
• Does the pain occur only on certain days of the week?
• Does the child stay home from school or is there early school dismissal because of the pain?
• What is the location/character/intensity/duration of the pain?
• Have any medications been tried, and what is the success of each of these? (Be sure to ask about complementary/alternative treatments being offered as well as conventional medications.)
• Is there any relationship between other prescribed/non prescribed medications or treatments and the onset of the pain?
• Have there been any changes in the child’s life recently, including family deaths, loss of a close friend or pet, moves, separation/divorce, school location or performance changes?
• What thoughts or fears do the parents or child have about the potential cause of the pain?
• Any history of recent travel, pets, or a family history of GI disorders?

Physical Examination
The physical exam in children with chronic abdominal complaints is also critical in helping separate functional from disease-related pain. The exam focuses on establishing not only growth parameters upon admission, but if possible, a trend of growth over the preceding months or years that may signal an organic disorder of the digestive tract. For example, a child presenting at the 50th percentile for weight and height may not appear concerning, but if he had been following the 90th percentile for weight until his symptoms started a few months earlier, this could point the practitioner to a more extensive evaluation for malabsorption, especially if additional symptoms are suggestive.

The physical exam, although comprehensive, also should focus on the abdomen, with careful palpation for masses, hernias, and organomegaly. 

Careful note should be taken of fever, rash, oral lesions, arthropathy, and a rectal exam with perianal inspection, and fecal occult blood testing should be performed whenever possible. It is important to recognize that school-aged children are usually independent when using the restroom, and parents do not usually have an accurate sense of their defecation patterns or completeness. Even the child herself may not pay close attention to her own defecation pattern and stool appearance, so answers to questions on this topic need to be interpreted within this context.

Laboratory Evaluation
A urinalysis helps diagnose infections or may uncover primary renal disease or calculi. A complete blood count (CBC) and differential may be helpful in identifying features of a chronic disease, such as a microcytic anemia, or even a blood-born malignancy presenting with GI complaints. An erythrocyte sedimentation rate (ESR) can help determine if an acute inflammatory process is present, although it is not specific for GI luminal disease. A comprehensive chemistry panel, including tests of liver function, electrolyte balance, renal function, and pancreatic enzymes, may help uncover a process in any of the visceral organs. Fecal occult blood testing, along with a fresh specimen for white blood cells, may suggest an intraluminal inflammatory process, and intestinal parasites are protean causes of abdominal pain in this age group.

Radiology
Radiologic imaging is often indicated, and it is important to tailor the imaging toward the suspected cause of the pain. For example, contrast radiography such as upper GI and small bowel follow-through x-rays can be helpful in diagnosing structural problems such as intestinal malrotation, pyloric stenosis, or bowel obstruction. However, contrast studies are not useful in quantifying disorders of GI tract function, such as gastroesophageal reflux, delayed gastric emptying, or disorders of the solid viscera such as the liver or spleen. Similarly, computed tomography (CT) can be quite helpful in identifying extraluminal disease such as an abscess, ruptured appendicitis, and pancreatic pseudocysts. However, it may miss gallbladder sludge or stones, or even pancreatic disease if the amount of oral contrast is insufficient to separate intraluminal from extraluminal contents.