Approach to chronic abdominal pain (pediatrics): Clinical sciences

Chronic abdominal pain is defined as constant, intermittent, or recurrent abdominal pain that’s present for at least two months. Associated symptoms to consider during an evaluation of chronic abdominal pain include growth and weight gain, changes in bowel habits, as well as the timing, pattern, and nature of the pain.

Underlying causes of chronic abdominal pain can be categorized as organic disorders, which have an anatomic, histologic, or physiologic etiology; and functional disorders, which do not have a clear organic cause.

When a pediatric patient presents with chronic abdominal pain, your first step is to perform an ABCDE assessment to determine if they’re stable or unstable. If unstable, stabilize their airway, breathing, and circulation; obtain IV or IO access; and administer intravenous fluids or packed red blood cells if indicated. Finally, implement continuous vital sign monitoring, including heart rate, respiratory rate, blood pressure, and pulse oximetry; and provide supplemental oxygen if needed.

Okay, let’s return to the ABCDE assessment and discuss stable patients. First, perform a focused history and physical examination. Your patient will report constant, intermittent, or recurrent abdominal pain, occasionally with symptoms like nausea, vomiting, diarrhea, or fever. The physical examination might reveal abdominal tenderness or distension. To evaluate further, assess your patient’s growth curve.

If your patient has had poor linear growth or suboptimal weight gain, your next step is to assess for bloody stools. The presence of blood in the stool should make you consider inflammatory bowel disease. These patients often report diffuse, crampy, periumbilical pain and fecal urgency. Some patients might have extraintestinal manifestations, like joint pain and swelling; eye redness or pain; and skin nodules or ulcers. There may also be a family history of inflammatory bowel disease.

The physical exam usually demonstrates abdominal tenderness, and you might notice skin findings, like erythema nodosum, which are painful nodules; a type of skin ulcer called pyoderma gangrenosum; or psoriatic lesions. To evaluate further, obtain a fecal calprotectin level, and order a colonoscopy with biopsies.

If the fecal calprotectin is elevated; if the colonoscopy shows a continuous pattern of edematous, erythematous, friable mucosa and erosions or ulcerations; and if the biopsy reveals mucosal and submucosal inflammation with erosions, ulcerations, and crypt abscesses; diagnose ulcerative colitis.

On the other hand, if the fecal calprotectin is elevated; but the colonoscopy demonstrates cobblestoning, a discontinuous pattern of skip lesions, with linear serpiginous ulcerations, and rectal sparing; and the biopsy shows transmural inflammation, and possibly granulomas; diagnose Crohn disease.

Now let’s move on and discuss patients with non-bloody stools. In this case, you should consider celiac disease. These patients might report bloating, and they often have diarrhea with or without constipation, as well as steatorrhea. Your patient might have a history of autoimmune or genetic conditions, such as thyroid disease, or a family history of celiac disease.

The physical exam may demonstrate abdominal distension, short stature or delayed puberty, and dermatitis herpetiformis, which refers to an itchy, vesicular rash that typically appears bilaterally on the elbows and knees.

Next, obtain total IgA and anti-TTG IgA levels, while your patient is on a diet containing gluten, and perform an esophagogastroduodenoscopy, or EGD, with biopsies. In celiac disease, the total IgA will be normal, and the anti-TTG IgA will be positive. If the EGD with biopsy demonstrates villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes, you can confirm a diagnosis of celiac disease.

Here’s a high-yield fact! The combination of chronic diarrhea, weight loss, and abdominal pain should prompt you to consider a Giardia intestinalis infection. This protozoan is a common cause of diarrheal outbreaks in daycare centers, causing acute or chronic symptoms.

Okay, now let’s consider those with normal growth and weight gain. First, assess for a change in stool frequency. Let’s start with patients who report increased stooling frequency. In this case, consider lactase deficiency. History might reveal diarrhea after ingesting dairy products or lactose-containing foods, as well as generalized, crampy abdominal pain with gas and bloating. Some patients may report a recent gastrointestinal illness or a family history of lactase deficiency. The exam might reveal abdominal tenderness or distension. Next, recommend a lactose elimination diet, and if your patient’s symptoms resolve, diagnose lactase deficiency.

Here’s a clinical pearl! More than half of the world’s population has some degree of lactase deficiency. Symptoms are related to the quantity of lactose ingested, but each individual has a different dose threshold at which symptoms develop!

Now, in some cases, stools may alternate between diarrhea and constipation. Here, you should consider irritable bowel syndrome, or IBS for short. These patients report symptoms for at least two months with abnormal frequency, form, or passage of stool; and the physical exam is typically normal.

To confirm the diagnosis, assess the Rome IV criteria for IBS. These include abdominal pain at least four days per month, plus one or more of the following: pain related to defecation, a change in stool frequency, or a change in stool appearance. Additionally, in children with constipation, the pain does not resolve after constipation resolves; and symptoms cannot be explained by another medical condition. If all of these criteria are met, diagnose irritable bowel syndrome.

Next let's look at the scenario where stool frequency is reduced. In this case consider functional constipation. History will reveal infrequent bowel movements, straining with defecation, and an absence of systemic symptoms like fever. The physical examination is usually normal, but some patients may have abdominal tenderness or distension, and you might detect palpable stool in the lower abdomen.