In which part of the gastrointestinal (GI) tract are diverticula least likely to occur?

Gastrointestinal Diverticula Distribution

Gastrointestinal diverticula do not typically occur in the rectum, as the rectum has a complete muscular layer without the anatomical weaknesses that predispose other parts of the gastrointestinal tract to diverticulum formation. 1

Anatomical Distribution of Diverticula

Diverticula can occur throughout most of the gastrointestinal tract but follow distinct patterns of distribution:

• Colon: Most common location for diverticula

  • Left colon (particularly sigmoid): Accounts for >75% of colonic diverticula 1
  • Right colon: Less common, but can occur especially in Asian populations 1
  • Cecum: Can develop diverticula 2

• Small Intestine:

  • Duodenum: Can develop diverticula 3
  • Jejunum: Can develop diverticula (80% of small bowel diverticula) 4
  • Ileum: Can develop diverticula (15% of small bowel diverticula) 4
  • Meckel's diverticulum: A specific type of ileal diverticulum 3

• Upper GI Tract:

  • Esophagus: Rare but can develop diverticula 3
  • Stomach: Rare but can develop diverticula (typically in the fundus) 5

Characteristics of Diverticula by Location

• Jejunal diverticula:

  • Tend to be large and multiple 4
  • Occur in 0.5-2.3% of imaging studies 6
  • Most common type of small bowel diverticula 6

• Ileal diverticula:

  • Usually small and solitary 4
  • Less common than jejunal diverticula 4

• Colonic diverticula:

  • Most prevalent in the sigmoid colon 2
  • Associated with low-fiber diet, obesity, smoking, and certain medications 2

Clinical Implications

• Diverticulitis complications:

  • Most commonly affects the sigmoid colon 2
  • Complications include abscess, peritonitis, obstruction, stricture, and fistula 2
  • First episode of diverticulitis is most often complicated rather than recurrences 2

• Small bowel diverticula:

  • Often asymptomatic but can present with vague abdominal discomfort 6
  • Perforation is the most severe complication, requiring prompt surgical intervention 6
  • Jejunal diverticulosis primarily affects the elderly, peaking in the sixth and seventh decades 4

Diagnostic Approach

• CT scan with oral and IV contrast is the gold standard for diagnosing diverticulitis (sensitivity and specificity of 95%) 1
• For small bowel diverticula, definitive diagnosis often requires laparoscopy or laparotomy 6
• Enteroclysis should be reserved for patients with persistent abdominal pain despite unrevealing endoscopic and contrast studies 4

In summary, while diverticula can occur in the cecum, duodenum, jejunum, and ileum, they are not typically found in the rectum due to its complete muscular layer structure.