What are the symptoms of Small Intestine Bacterial Overgrowth (SIBO)?

Symptoms of Small Intestinal Bacterial Overgrowth (SIBO)

The primary symptoms of Small Intestinal Bacterial Overgrowth (SIBO) include abdominal bloating, diarrhea, abdominal pain/discomfort, flatulence, and in more severe cases, malnutrition and weight loss. 1

Core Symptoms

SIBO presents with a constellation of gastrointestinal symptoms that significantly impact quality of life:

• Abdominal bloating and distention - Often worse after meals 2, 1
• Diarrhea - Chronic, watery diarrhea is common 2, 1
• Abdominal pain/discomfort - Can range from mild to severe 1, 3
• Flatulence - Excessive gas production 2, 1
• Altered bowel habits - Including constipation in some cases 2

Advanced/Severe Symptoms

In more advanced or severe cases, SIBO can lead to:

• Malabsorption - Resulting in nutritional deficiencies 1, 3
• Weight loss - Due to malabsorption and malnutrition 1
• Steatorrhea (fatty stools) - Particularly in severe cases 3
• Vitamin deficiencies - Especially B12, fat-soluble vitamins (A, D, E), iron, and magnesium 1, 3
• Elevated folate levels - Due to bacterial production 3

Special Considerations

SIBO symptoms may overlap with or be confused with other conditions:

• Symptoms can mimic Irritable Bowel Syndrome (IBS) 3
• SIBO is particularly common in patients with:
  • Inflammatory Bowel Disease (up to 30% in Crohn's Disease) 2
  • Chronic pancreatitis (up to 92% in patients with pancreatic exocrine insufficiency) 2
  • Post-surgical patients, especially those with altered anatomy 1
  • Systemic conditions affecting gut motility 1

Diagnostic Clues

While symptoms alone cannot definitively diagnose SIBO, certain patterns may increase suspicion:

• Symptoms worsening after carbohydrate-rich meals 1
• Symptoms improving temporarily with antibiotics 1
• Chronic symptoms resistant to conventional treatments 4
• History of predisposing conditions (bowel surgery, radiation damage, motility disorders) 1

Clinical Pitfalls to Avoid

• Don't rely solely on symptoms for diagnosis - breath testing with glucose or lactulose, or small bowel aspirates are recommended for confirmation 2, 1
• Don't overlook SIBO in patients with stricturing or fistulizing Crohn's disease 2
• Don't miss nutritional deficiencies that may indicate more severe or chronic SIBO 1
• Don't confuse SIBO symptoms with functional gastrointestinal disorders without proper testing 3

SIBO remains underrecognized despite its significant impact on quality of life. Recognizing its diverse symptom presentation is crucial for timely diagnosis and effective management.