Small Intestinal Bacterial Overgrowth: Symptoms, Causes, Diagnosis and Treatment

Written by Medicover Team and Medically Reviewed by Dr Raosaheb Rathod , Gastroenterologists Medical

Causes
Find a Doctor
Diagnosis
Treatment
FAQs
Book an Appointment

1. Causes 2. Find a Doctor 3. Diagnosis 4. Treatment 5. FAQs

Small Intestinal Bacterial Overgrowth (SIBO) is a digestive disorder that occurs when excessive bacteria grow in the small intestine. This abnormal increase in bacteria can disrupt normal digestion and interfere with the absorption of nutrients, leading to symptoms such as bloating, abdominal discomfort, gas, diarrhea, and nutritional deficiencies. Early diagnosis and appropriate treatment can help restore digestive balance and improve overall gut health.

What are the Types of Small Intestinal Bacterial Overgrowth?

Small Intestinal Bacterial Overgrowth (SIBO) is categorized into three main types based on the predominant gas produced by the bacterial overgrowth:

Hydrogen-Dominant SIBO

This type is characterized by high levels of hydrogen gas and is often associated with diarrhea, bloating, and abdominal discomfort. It is caused by an overproduction of hydrogen gas by certain bacteria during carbohydrate fermentation.

Methane-Dominant SIBO

This type, referred to as intestinal methanogen overgrowth (IMO), occurs when archaea (microorganisms) in the gut produce methane gas, leading to symptoms such as constipation, bloating, and abdominal pain.

Hydrogen sulfide SIBO

It is less common and characterized by excessive production of hydrogen sulfide gas, which may cause symptoms like diarrhea, a rotten egg odor in the breath, and other gastrointestinal disturbances. Identifying the type of SIBO is crucial for targeted treatment, as the approach varies depending on the specific gas involved.

What are the Symptoms of Small Intestinal Bacterial Overgrowth?

Recognizing the symptoms of SIBO is the first step toward diagnosis and treatment. Small Intestinal Bacterial Overgrowth (SIBO) occurs when there is an abnormal increase in the number of bacteria in the small intestine. The symptoms can vary but often include:

Bloating: A feeling of fullness or pressure in the abdomen, often exacerbated after meals.
Abdominal Discomfort or Pain: Cramps or pains in the stomach area, which may worsen after eating.
Diarrhea: Loose, frequent stools may occur, sometimes with an urgency to go.
Constipation: Some people with SIBO may experience constipation instead, or alternating diarrhea and constipation.
Excessive Gas: Increased gas production, leading to belching or flatulence.
Indigestion: Difficulty digesting food, sometimes leading to a sensation of food being "stuck."
Malabsorption: Due to bacteria interfering with the absorption of nutrients, symptoms can include unintentional weight loss, vitamin deficiencies, and fat malabsorption (leading to greasy, foul-smelling stools).
Nausea: A sensation of queasiness or a feeling of an unsettled stomach.
Fatigue: Chronic tiredness or exhaustion that may result from nutrient deficiencies or the body's response to the bacterial overgrowth.

What are the Causes of Small Intestinal Bacterial Overgrowth?

Understanding what causes SIBO can help in its prevention and treatment. Here are some common causes:

Structural Abnormalities

Diverticula: Small pouches in the intestine can trap bacteria.
Surgery: Procedures that affect the intestine can lead to SIBO.

Motility Disorders

Irritable Bowel Syndrome (IBS): People with IBS often have SIBO.
Diabetes: High blood sugar can affect intestinal movement.

Low Stomach Acid (Hypochlorhydria)

Aging or Medications: Proton pump inhibitors (PPIs) and antacids can reduce stomach acid, impairing its ability to kill harmful bacteria.

Immune System Deficiencies

Immunodeficiency Diseases: Conditions like HIV/AIDS or immunosuppressant medications may contribute.

Altered Gut Flora

Antibiotic Overuse: Disrupts the balance of gut bacteria.
Diet High in Sugars and Carbohydrates: Can feed harmful bacteria and promote their growth.

Other Health Conditions

Celiac Disease: This condition can damage the intestine, leading to bacterial overgrowth.
Immune System Disorders: A weakened immune system can fail to keep bacterial growth in check.

When to See a Doctor for Small Intestinal Bacterial Overgrowth?

Persistent bloating, abdominal discomfort, chronic diarrhea, unexplained weight loss, or symptoms of nutrient deficiencies should be evaluated by a Gastroenterologist. Early diagnosis can help prevent complications related to malabsorption and poor nutrition.

You should see a doctor if you have:

Ongoing bloating and excessive gas
Persistent diarrhea or constipation
Unexplained weight loss or fatigue

Get medical help immediately if:

Severe dehydration from prolonged diarrhea
Signs of significant malnutrition
Severe abdominal pain or persistent vomiting

These could be signs of a serious complication like Small Intestinal Bacterial Overgrowth, which needs urgent care.

Find Gastroenterologists-medical for Small Intestinal Bacterial Overgrowth Treatment Near You

How is Small Intestinal Bacterial Overgrowth Diagnosed?

Diagnosis usually involves a combination of medical history, symptoms, and tests. Here are some common diagnostic methods:

Breath Tests

Hydrogen Breath Test: The most common diagnostic tool for SIBO. After consuming a sugar solution like glucose or lactulose, exhaled breath is measured for hydrogen or methane levels. High levels suggest bacterial overgrowth.
Methane Breath Test: Measures methane gas, which is produced by specific bacteria, to identify methane-predominant SIBO.

Endoscopy

In some cases, a doctor might perform an endoscopy to collect a sample from the small intestine. This sample is then tested for bacterial growth.

Blood Tests

Blood tests can check for nutritional deficiencies and other signs that might suggest SIBO.

Imaging Tests

Abdominal X-rays, CT scans, or MRIs may be used to identify anatomical abnormalities, obstructions, or motility disorders contributing to SIBO.

What are the Treatment of Small Intestinal Bacterial Overgrowth?

Treating SIBO usually involves a combination of antibiotics, diet changes, and probiotics.

Antibiotics

Antibiotics are often the first line of treatment. They can help reduce the number of bacteria in the small intestine. Common antibiotics used include rifaximin and metronidazole.

Diet Changes

Diet plays a crucial role in managing SIBO. Many people follow a low-FODMAP diet, which reduces foods that ferment in the gut. Another approach is the Specific Carbohydrate Diet (SCD), which eliminates certain types of carbohydrates.

Probiotics

Probiotics can help restore the balance of good bacteria in the gut. They can be taken as supplements or found in foods like yogurt and kefir.

Treatment of Underlying Causes

Improving Motility: Prokinetic agents like prucalopride or low-dose erythromycin may be prescribed to enhance intestinal movement.
Surgical Intervention: For structural abnormalities such as adhesions or strictures, surgery may be required.
Addressing Nutritional Deficiencies: Supplementation of vitamin B12, fat-soluble vitamins (A, D, E, K), or iron may be needed.

Your health is everything - prioritize your well-being today.

Consult Small Intestinal Bacterial Overgrowth Doctors Today

What is the Recovery Process for Small Intestinal Bacterial Overgrowth?

Recovery from SIBO depends on the severity of bacterial overgrowth, underlying causes, and response to treatment. Many patients experience symptom improvement within weeks of starting therapy, although recurrence can occur if contributing factors remain untreated.

Long-term management often includes dietary modifications, ongoing monitoring, and treatment of underlying gastrointestinal conditions.

Recovery Includes

Completion of prescribed antibiotic therapy
Gradual improvement in digestive symptoms
Correction of nutritional deficiencies
Dietary and lifestyle adjustments
Regular follow-up with a gastroenterologist

Frequently Asked Questions

1. Does SIBO ever fully go away?

SIBO can be fully treated with proper antibiotics and lifestyle changes, but it may recur. Ongoing management and addressing underlying conditions help prevent recurrence.

2. How to avoid getting SIBO?

To avoid SIBO, maintain a healthy diet, manage stress, avoid unnecessary antibiotics, and address any underlying digestive issues promptly.

3. Is SIBO life-threatening?

SIBO is not typically life-threatening but can lead to severe nutrient deficiencies and complications if left untreated. Proper diagnosis and treatment are essential.

4. What naturally kills bad bacteria in the gut?

Probiotics, fermented foods, a high-fiber diet, and certain natural antimicrobials like garlic and oregano oil can help balance gut bacteria and reduce harmful bacteria.

5. What is the root cause of SIBO?

SIBO is often caused by an imbalance in gut motility, anatomical abnormalities, or conditions that affect the small intestine, leading to bacterial overgrowth.