What interventions are recommended for an 11-year-old patient with a 3-day history of constipation, lower abdominal pain, and a previous appendectomy (surgical removal of the appendix)?

Management of an 11-Year-Old with Constipation and Lower Abdominal Pain After Appendectomy

Begin immediate fluid resuscitation with intravenous fluids, maintain NPO status, obtain CT scan with contrast to rule out bowel obstruction or stump appendicitis, and initiate aggressive bowel management with polyethylene glycol while monitoring for surgical complications. 1, 2

Immediate Assessment and Stabilization

Evaluate vital signs immediately to detect hemodynamic instability, including blood pressure, heart rate, and temperature, as bowel obstruction can progress rapidly in pediatric patients. 1 The history of previous appendectomy creates 85% sensitivity and 78% specificity for adhesive small bowel obstruction, making this a critical diagnostic consideration. 2

Key Physical Examination Findings to Assess:

• Abdominal distension and degree of tenderness - localized peritonism suggests surgical complication rather than simple constipation 2
• Presence of bowel sounds - absent sounds indicate ileus or obstruction 2
• Palpable mass in right lower quadrant - may indicate fecal impaction, stump appendicitis, or abscess 3, 4
• Rectal examination - assess for impaction and rule out distal obstruction 2

Essential Laboratory Tests:

• Complete blood count - leukocytosis >14,000/μL suggests infection or ischemia 2, 1
• C-reactive protein - elevated levels indicate inflammatory process 2, 1
• Electrolytes - assess for metabolic disturbances from vomiting or obstruction 2
• Stool for C. difficile toxin - prior surgery increases risk of infection 2

Diagnostic Imaging Priority

CT scan of abdomen and pelvis with intravenous contrast is the imaging study of choice with higher sensitivity for detecting intestinal obstruction, mesenteric ischemia, and identifying surgical complications like stump appendicitis. 1 This is critical because stump appendicitis, though rare, must be considered in any patient with prior appendectomy presenting with right lower quadrant pain. 4

The CT will identify:

• Mechanical bowel obstruction - adhesions cause 55-75% of small bowel obstructions in post-surgical patients 2
• Stump appendicitis - inflammation of residual appendiceal tissue 4
• Intra-abdominal abscess - may present with similar symptoms 5
• Fecal loading patterns - right-sided retention correlates with bloating and pain 3

Initial Medical Management

Bowel Rest and Fluid Management:

• NPO status immediately to decompress the bowel 1
• Intravenous fluid resuscitation to maintain hydration and perfusion 1
• Nasogastric tube placement if vomiting persists or obstruction suspected 2

If Imaging Rules Out Obstruction and Surgical Complications:

Initiate aggressive bowel regimen with polyethylene glycol 3350 dissolved in 4-8 ounces of water, as this is FDA-approved for constipation and works by retaining water in stool to soften it. 6 This should produce bowel movement within 2-4 days. 6

Add stimulant laxative (bisacodyl 10-15 mg, 2-3 times daily) with goal of one non-forced bowel movement every 1-2 days. 2 If impaction is present on rectal exam, glycerine suppositories or manual disimpaction may be necessary. 2

Consider adding lactulose, magnesium hydroxide, or magnesium citrate if constipation persists despite initial therapy. 2

Surgical Consultation Criteria

Obtain urgent surgical consultation if any of the following are present:

• Signs of peritonitis - rebound tenderness, guarding, rigidity 1
• Complete bowel obstruction on imaging 1
• Hemodynamic instability despite resuscitation 1
• Leukocytosis >14,000/μL with localized peritonism - suggests stump appendicitis or abscess 2, 4
• Failure to pass gas or stool with progressive distension 2

Mortality increases by 2-12% with each hour of delay when obstruction or ischemia is present. 1

Special Considerations for Post-Appendectomy Patients

The history of appendectomy significantly alters the differential diagnosis. Patients with previous appendectomy have prolonged colonic transit time compared to those without, suggesting altered bowel motility that predisposes to constipation. 3 However, the 3-day duration with lower abdominal pain raises concern for:

• Adhesive small bowel obstruction - most common cause in post-surgical patients 2
• Stump appendicitis - rare but must be excluded with imaging 4
• Fecal impaction with secondary obstruction - can mimic surgical pathology 3

Critical Pitfalls to Avoid

Do not assume this is simple constipation without imaging - the combination of prior surgery, 3-day duration, and lower abdominal pain requires exclusion of mechanical obstruction. 2, 1

Do not delay surgical consultation if peritoneal signs develop - mortality increases significantly with delayed intervention. 1

Do not administer oral laxatives if bowel obstruction is suspected - this can worsen distension and increase perforation risk. 2

Do not miss stump appendicitis - maintain high index of suspicion in any post-appendectomy patient with right lower quadrant pain, as this entity is always possible. 4

Follow-Up Management

If conservative management is successful and imaging shows only fecal retention without obstruction, continue polyethylene glycol for up to 2 weeks as directed by FDA labeling. 6 Prolonged use beyond this requires physician supervision due to risk of electrolyte imbalance and laxative dependence. 6

Educate about dietary fiber intake, adequate fluid consumption, and regular physical activity to prevent recurrence. 2, 3 Faecal retention is a common underlying factor in functional bowel disorders and can lead to chronic complications if not addressed. 3