Abdominal Pain

Chapter 17 Abdominal Pain

ETIOLOGY

EVALUATION

How Does Pain Location Help Determine the Likely Cause?

Visceral pain tends to be poorly localized and aching or cramping in nature. In contrast, pain from somatic structures, such as the abdominal wall musculature, is easily defined as coming from a well-circumscribed area. Sometimes, as is the case with appendicitis, the discomfort begins as ill-defined visceral pain, becoming much more intense and well localized as overlying somatic structures become involved. Pain arising from the small intestine is typically periumbilical in location. Proximal gut injury (esophagus, stomach, and duodenum) tends to cause epigastric discomfort, as does inflammation of the pancreas and gallbladder. Problems arising in the colon are typically perceived directly in the same region of the abdomen.

How Do I Evaluate Acute Abdominal Pain?

Acute abdominal pain is defined as a condition of recent onset, with characteristics that indicate an urgent need for diagnosis and management. You must obtain a precise history, examine the child carefully, and, finally, order appropriate tests. Table 17-1 summarizes the information you must gather to evaluate the child with acute abdomen. Not all of the studies listed in Table 17-1 must be performed in all patients. If your history and examination lead you directly to a particular diagnosis, such as constipation, you may treat it directly.

Table 17-1 Evaluation of the Child with Acute Abdominal Pain

History
Onset	Sudden vs. gradual, preceding injury, prior episodes
Associated symptoms	Fever, nausea, dysuria, diarrhea, constipation, bloody stools or emesis, cough
Location of pain	Periumbilical, epigastric, right lower quadrant, left lower quadrant, well-localized or vague
Nature of pain	Aching, cramping, dull, sharp, burning, constant vs. colicky
Progression	Worsening, improving, changing location
Physical Examination
General	Hydration, appearance of toxicity, growth and weight gain
Chest	Crackles, rhonchi, wheezing, tenderness of musculoskeletal structures
Abdomen	Distention, bowel sounds, tenderness (location, severity, rebound, superficial vs. deep), mass
Rectal examination	Fecal impaction, occult blood, pelvic tenderness, extrinsic mass
Laboratory/Radiologic Evaluation
CBC	Evidence of infection or inflammation
ESR and CRP	Evidence of inflammation or infection
Amylase, lipase	Pancreatitis
GGT	Bile duct obstruction or injury
ALT, AST	Hepatitis
Urinalysis	Urinary tract infection, hematuria (stones, obstruction)
Plain x-rays	Bowel gas pattern, evidence of obstruction, free peritoneal air, constipation, kidney stones, appendiceal fecalith
CT or ultrasound	Appendiceal abscess, intussusception, gallstones, pancreatitis, bile duct obstruction, kidney stones, renal anomalies
Barium enema	Intussusception, malrotation, less useful for appendicitis

ALT, Alanine transaminase; AST, aspartate transaminase; CBC, complete blood count; CRP, C-reactive protein; CT, computed tomography; ESR, erythrocyte sedimentation rate; GGT, gamma-glutamyltransferase.

When Should I Obtain Surgical Consultation?

Acute appendicitis should be carefully considered when evaluating any patient with acute abdominal pain. Not all patients exhibit typical features, especially if the appendix is located retrocecally or in another atypical location. Perforation of the appendix usually occurs within 24 to 48 hours of symptom onset. Therefore, you must work rapidly and enlist the help of your colleagues early in the evaluation. Surgeons should also be consulted promptly when there is evidence of obstruction, peritonitis, or mass lesion.

What Causes Recurrent Abdominal Pain?

Table 17-2 lists most of the more common causes plus features on history, physical examination, and laboratory testing that may suggest the diagnosis.

Table 17-2 Differential Diagnosis of Recurrent Abdominal Pain