Differential Diagnosis

The differential diagnosis for abdominal pain in children is very broad, and it can be approached in different ways (Figure 5-2). Certain conditions occur more commonly at specific ages and therefore it may be useful to classify causes of acute abdominal pain based on age. Pain may also be classified as surgical or medical (Table 5-1).

Figure 5-2 The acute abdomen.

Across all ages, gastroenteritis and appendicitis are the most common medical and surgical causes of acute abdominal pain, respectively. Malrotation with midgut volvulus is the single most devastating abdominal surgical emergency of childhood (see Chapter 109).

Life-threatening causes of abdominal pain include those related to trauma, intestinal obstruction, and peritoneal irritation. Examples of processes that present with intestinal obstruction are intussusception, midgut volvulus, and extrinsic obstruction caused by adhesions from prior surgery. Peritoneal irritation may be secondary to inflammation or perforated viscus; examples include necrotizing enterocolitis in a neonate, acute appendicitis, and ruptured ectopic pregnancy.

Abdominal pain can also be classified based on the location of the pain. A classic approach is by dividing the abdomen into four quadrants (Figure 5-3). This can help the practitioner direct the workup to rule in or out the most common diagnoses based on the location of symptoms. For example, hepatic and gallbladder disease usually present with right upper quadrant pain (see Chapter 115). Appendicitis classically presents with migration of pain to the RLQ. Gastritis or peptic ulcer disease may present with left upper quadrant pain (see Chapter 108).

Figure 5-3 Quadrants of the abdomen.

History

The initial evaluation of acute abdominal pain is particularly challenging in pediatrics because children often cannot describe, articulate, or localize their symptoms. This is often exacerbated by anxiety, making it harder for the clinician to examine and identify positive findings.

Pain Character

Acute abdominal pain caused by a medical or surgical emergency typically increases in intensity over time, may awaken the child at night, and likely interferes with activity. In addition to the age of patient and the location of the pain, other important features of the history include the onset, frequency and duration, pattern, associated symptoms, and pertinent medical history.

Infants and young children can seldom localize their pain, and parents often describe an inconsolable child who lies with his or her legs drawn up to the chest. Asking the parents if they think the child is in pain can be helpful to distinguish pain from fussiness or irritability. Pain that is intermittent, with paroxysms of cramping inconsolable pain alternating with return to normal state, is characteristic of intussusception (Figure 5-4). Peritoneal irritation is suggested by pain that is worse with movements that change the tension of the abdominal wall, such as a bumpy car ride or walking. Pain that improves after vomiting or a bowel movement reflects a small bowel or large bowel cause, respectively.

Figure 5-4 Intussusception.