Differential Diagnosis for Lower Abdominal Pain in a 59-Year-Old Male Post-Appendectomy

Single Most Likely Diagnosis

• Adhesions or Internal Hernia: Given the recent history of appendectomy, adhesions or internal hernia are plausible causes of lower abdominal pain. These conditions can occur as a complication of surgery, leading to bowel obstruction or intermittent pain.

Other Likely Diagnoses

• Incisional Hernia: A possible complication following abdominal surgery, which can cause pain, especially if the hernia becomes incarcerated.
• Wound Infection or Abscess: Although the patient denies fever, a localized wound infection or abscess could cause pain without systemic symptoms.
• Constipation: Despite reporting normal bowel movements, constipation can sometimes present with abdominal pain, and the patient's recent surgery and possible use of pain medications could contribute to this condition.

Do Not Miss Diagnoses

• Bowel Obstruction: A serious condition that requires prompt diagnosis and treatment. It could be related to adhesions from the recent surgery.
• Appendiceal Stump Leak or Residual Appendicitis: Although less common, if the appendectomy was not fully successful, or there was a leak from the appendiceal stump, it could lead to severe infection or abscess formation.
• Diverticulitis: Especially in a 59-year-old, diverticulitis is a significant consideration for lower abdominal pain and could be life-threatening if perforation occurs.

Rare Diagnoses

• Lead Point for Intussusception: Though more common in children, intussusception can occur in adults, often with a lead point such as a tumor.
• Mesenteric Ischemia: A rare but serious condition that could present with abdominal pain out of proportion to physical findings.
• Inflammatory Bowel Disease (IBD) Flare: If the patient has a history of IBD, a flare could cause lower abdominal pain, though the recent surgery might complicate this diagnosis.

Workup

The workup for this patient should include:

• Complete Blood Count (CBC): To check for signs of infection or inflammation.
• Basic Metabolic Panel (BMP): To assess for electrolyte imbalances that could suggest bowel obstruction or other complications.
• Imaging:
  • CT Scan of the Abdomen and Pelvis: Useful for evaluating the post-surgical abdomen, detecting complications such as abscesses, bowel obstruction, or hernias.
  • Ultrasound: Could be used as an initial, non-invasive method to evaluate for hernias or fluid collections.
• Surgical Follow-Up: Consultation with the surgeon who performed the appendectomy to discuss possible complications and the need for further intervention.