Understanding Small Intestinal Bacterial Overgrowth (SIBO): A Complete Guide for Patients

Table of Contents

• Key Points
• What Is Small Intestinal Bacterial Overgrowth?
• How Common Is SIBO?
• What Causes SIBO? The Underlying Mechanisms
• Reduced Stomach Acid and SIBO
• Motility Disorders and SIBO
• Structural Abnormalities of the Digestive Tract
• The Role of the Immune System
• Who Is at Risk for SIBO?
• Symptoms of SIBO
• Complications of SIBO
• How Is SIBO Diagnosed?
• Treatment Options
• Study Limitations
• Recommendations for Patients
• Frequently Asked Questions
• Source Information

Key Points

• SIBO occurs when bacteria in the small intestine exceed normal levels, triggering symptoms like bloating, diarrhea, and abdominal pain.
• Prevalence in older adults ranges from 14.5% to 15.6%; in disabled older adults it was 33%.
• In a study, SIBO was found in 43% of diabetic patients with chronic diarrhea; 75% improved with antibiotics.
• Diagnosis uses bacterial culture of small bowel aspirate or glucose/lactulose breath tests; results vary by test and criteria.
• Antibiotic treatment, such as rifaximin or tetracycline, can resolve symptoms in many patients, including those with celiac disease.

What Is Small Intestinal Bacterial Overgrowth?

Small intestinal bacterial overgrowth, commonly called SIBO, is a condition defined by the presence of excessive bacteria in the small intestine. To put it in medical terms, SIBO is diagnosed when the bacterial population in the small intestine exceeds 10⁵–10⁶ organisms per milliliter of fluid. Normally, less than 10³ organisms per milliliter are found in the upper small intestine, and most of these are Gram-positive bacteria.

It is important to understand that both the number and the type of bacteria matter. A predominance of bacteria that break down bile salts into unconjugated or insoluble compounds can lead to fat malabsorption or bile acid diarrhea. In contrast, microorganisms that preferentially break down carbohydrates into short-chain fatty acids and gas may produce bloating without diarrhea, because those metabolic byproducts can be absorbed. Some Gram-negative bacteria, such as Klebsiella species, can produce toxins that damage the intestinal lining, interfering with the absorption of nutrients and causing fluid secretion — a pattern that mimics a condition called tropical sprue.

How Common Is SIBO?

A common misconception is that SIBO affects only a limited number of patients, such as those with an anatomic abnormality of the upper gastrointestinal tract or those with a motility disorder. However, the evidence suggests that SIBO may be far more prevalent than previously thought. This apparent increase may be due, in part, to improved diagnostic tests that are more readily available today.

An extensive search of the medical literature found no study evaluating the incidence of SIBO in healthy volunteers — meaning we don't know exactly how many new cases occur each year. However, several studies provide useful prevalence data:

• A study of 294 nonhospitalized older adults, with 34 younger adults (average age 33.6 years) as healthy controls, found the prevalence of SIBO by glucose breath test was 5.9% in the control group versus 15.6% in the older group.
• A study of healthy older adults from Japan (average age 74.7 years) found no patients with SIBO using a glucose breath test.
• An Australian study detected SIBO in 0% of healthy controls (average age 59) by duodenal aspirates, although 13% were positive for SIBO using a lactulose breath test.
• Healthy elderly volunteers in the United Kingdom had a 14.5% prevalence rate for SIBO based on a positive glucose breath test.
• In a study of 111 patients with irritable bowel syndrome (IBS), 20% of healthy age- and sex-matched controls had an abnormal lactulose breath test suggestive of SIBO.

In summary, although the data are limited, prevalence rates of SIBO in young and middle-aged adults appear to be low, whereas prevalence rates appear to be consistently higher in older patients — ranging from 14.5% to 15.6%. These rates, however, depend heavily on which diagnostic test is used (see the Diagnosis section below).

What Causes SIBO? The Underlying Mechanisms

SIBO develops when the normal homeostatic (self-regulating) mechanisms that control bacterial populations in the gut are disrupted. The two most common predisposing factors are diminished gastric acid secretion (reduced stomach acid) and small intestine dysmotility (impaired movement of food through the intestine). Disturbances in gut immune function and anatomical abnormalities of the gastrointestinal tract also increase the likelihood of developing SIBO.

Once present, bacterial overgrowth may trigger an inflammatory response in the intestinal mucosa (the lining of the intestine), which further worsens the typical symptoms. Although not universally seen, overgrowth of small bowel flora may result in microscopic mucosal inflammation. Analysis of small bowel biopsies in elderly patients with bacterial overgrowth revealed blunting of the intestinal villi (the finger-like projections that absorb nutrients), thinning of the mucosa and crypts, and increased intraepithelial lymphocytes. Importantly, all of these changes reversed with antibiotic treatment.

Reduced Stomach Acid and SIBO

Stomach acid plays a vital protective role: it suppresses the growth of ingested bacteria, thereby limiting bacterial counts in the upper small intestine. Diminished acid production, a condition known medically as hypochlorhydria, is a risk factor for SIBO. It can develop after colonization with Helicobacter pylori (the bacteria that causes ulcers) or as a consequence of aging.

The medications people take for acid reflux may also play a role. Treatment with histamine type 2 receptor blockers (H2RAs) such as cimetidine led to SIBO in 18 adult patients, as measured by bile acid breath tests and jejunal aspirates. A prospective study of 47 outpatients treated with either omeprazole (20 mg/day) or cimetidine (800 mg/day) found that bacterial overgrowth was present in 53% of patients who received omeprazole, compared to 17% who received cimetidine (P<.05). This means the difference is statistically significant, with less than a 5% chance it was due to random variation. Another study found that 20 patients treated with 4 weeks of omeprazole had a significant increase in duodenal bacterial counts compared to baseline, as measured by endoscopic aspirate.

The authors note that these disparate results may represent a true medication effect or, alternatively, reflect the small number of patients studied and differences in assay techniques. Also of interest: bacterial overgrowth can lead to a false positive H. pylori diagnosis using urea-based testing, because some overgrown bacterial strains are urease-positive.

Motility Disorders and SIBO

Normal gastrointestinal motility involves a complex, tightly coordinated series of events designed to move material through the digestive tract. During periods of fasting, a wave of electrical and muscular activity called the migrating motor complex (MMC) develops approximately every 90–120 minutes. Its job is to sweep residual debris through the GI tract — like a janitorial service for your intestines. Several studies have demonstrated that abnormalities in the MMC may predispose people to SIBO, because bacteria are not effectively swept from the proximal bowel into the colon.

Several specific conditions can disrupt this process:

• Gastroparesis — a chronic disorder of delayed gastric emptying that can develop from long-standing diabetes, connective tissue disorders, a prior viral infection, or ischemia (reduced blood flow). Impaired stomach contractions lead to stasis (stagnation) of food and bacteria in the upper GI tract.
• Cirrhosis with portal hypertension — patients with this condition had retrograde (backward) pressure waves in the proximal duodenum, clustered contractions, and abnormalities of the MMC, leading to a greater prevalence of SIBO.
• Chronic renal failure — patients have neuropathic-like motor abnormalities in the small intestine and are more likely to develop bacterial overgrowth.
• Neuropathic processes such as chronic intestinal pseudo-obstruction (CIP), and myopathic processes such as scleroderma and polymyositis, are likely to be associated with SIBO. In a small group of systemic sclerosis patients with more than 10⁵ colony-forming units per microliter on duodenal aspiration, 7 out of 8 patients had positive lactulose breath tests.

Structural Abnormalities of the Digestive Tract

Structural abnormalities in the GI tract provide an ideal environment for bacterial colonization and overgrowth. GI tract surgeries that create a "blind loop" — such as a Billroth II procedure or a Roux-en-Y anastomosis — predispose to bacterial stasis and overgrowth due to abnormal motility and ineffective clearance of retained food and secretions. Patients who have undergone jejunoileal bypass, an end-to-side enteroenteric anastomosis, or the creation of a Koch distal ileal pouch are also at risk.

Other structural risk factors include:

• Small bowel diverticula (pouches that form in the intestinal wall) — these occur in approximately 1–6% of the population based on autopsy and radiographic studies. They are generally incidental, asymptomatic, and small in size. However, large duodenal and jejunal diverticula can harbor bacteria and lead to SIBO symptoms.
• Strictures (narrowing) of the small intestine — these can develop after surgery, after radiation, in association with Crohn's disease, or secondary to medication use.
• Resection of the ileocecal valve — this valve normally prevents bacteria from moving backward from the colon into the small intestine. One study of Crohn's patients found that resection of the ileocecal valve significantly increased the prevalence of SIBO from 18% to 30%.

The Role of the Immune System

Patients who are immunodeficient — whether due to an abnormal antibody response or T-cell response — are prone to bacterial overgrowth. Studies show that patients with SIBO (compared to those with normal jejunal aspirates) are more likely to have abnormalities in intestinal mucosal immunity, evidenced by increased luminal immunoglobulin A (IgA) concentrations and lamina propria IgA plasma cell counts. Interestingly, patients with deficiencies in humoral or cellular immunity do not appear to be predisposed to SIBO, as they have normal intestinal microflora.

Who Is at Risk for SIBO?

SIBO can develop in a variety of patient populations. Here is a breakdown of the specific groups and the evidence behind each risk factor.

Irritable Bowel Syndrome (IBS)

There is significant interest in the possible role of SIBO in the generation of IBS. Many IBS symptoms are nonspecific (bloating, distention, cramping, abdominal discomfort) and can mimic symptoms of SIBO. But the research results are strikingly inconsistent:

• In an uncontrolled study by Pimentel and colleagues, 78% of 202 patients who met the Rome I criteria for IBS had an abnormal lactulose breath test suggestive of SIBO.
• A blinded, randomized study found that 84% of patients who met Rome I criteria for IBS had an abnormal lactulose breath test, compared to 20% of healthy volunteers.
• Another research group reported a prevalence rate of 65% in 98 consecutive IBS patients.
• However, in 85 consecutive patients meeting the Rome II criteria for IBS, none had SIBO using glucose breath testing.
• Walters and Vanner reported that only 10% of their IBS patients (Rome II criteria) had SIBO using the lactulose breath test.

Given these widely discordant results, there is considerable debate in the scientific community about the potential relationship between IBS and SIBO. Delayed transit, disordered motility, or abnormalities in the MMC — all of which can occur in IBS patients — could potentially predispose these patients to SIBO.

Diabetes and Metabolic Disorders

Long-standing and poorly controlled diabetes can injure the enteric nervous system, leading to disordered GI motility. Diabetic gastroparesis and neuropathic small bowel motility disorders are both associated with SIBO. A recent study found that SIBO was present in 43% of diabetic patients with chronic diarrhea, and 75% had a significant improvement in their symptoms after being treated with antibiotics. Additionally, in a group of 82 diabetic patients, of those who had carbohydrate malabsorption on an oral glucose tolerance test, 75% were diagnosed with SIBO.

Older Adults

Mitsui and colleagues, using a glucose breath test, found that 33% of disabled older adults had SIBO. Parlesak and coworkers showed that 15.6% of older, nonhospitalized adults had SIBO, and Lewis and associates reported similar data at 14.5%.

Although it is commonly believed that SIBO develops in the elderly because of age-associated decline in GI motility, most studies have not shown a significant decrease in GI motility with aging. Rather, other factors likely play a role, including medications that slow GI motility, a decline in physical mobility, the onset of new diseases (such as diabetes), dietary changes that lead to malnutrition, and changes in gut immune function.

Celiac Disease

Long-standing celiac disease can disturb gut motility, leading to small intestine dysmotility. A study of 15 celiac patients with persistent symptoms despite adherence to a strict gluten-free diet found that 66% had bacterial overgrowth on lactulose breath testing. All of these patients noted a resolution of their symptoms after being treated for bacterial overgrowth.

Chronic Diarrhea

A recent study evaluated the role of SIBO in 87 consecutive patients with chronic diarrhea. All patients underwent extensive testing to exclude structural, metabolic, inflammatory, and acute infectious processes. Celiac disease and inflammatory bowel disease were ruled out by both laboratory and endoscopic testing. The authors reported that SIBO was present in 33% of the patients using small bowel culture, compared to 0% in healthy controls.

Other Organ Dysfunction

GI symptoms are common in patients with renal failure and include nausea, early satiety, bloating, and abdominal pain. Although these symptoms are often attributed to uremia (buildup of waste products in the blood), they may actually reflect altered gut motility and SIBO. A study of 22 patients with chronic renal failure found that 50% had evidence of a neuropathic motility disorder, as measured by antroduodenojejunal manometry. SIBO was more prevalent in patients with neuropathic motility disorders (55%) compared to those without (18%; P=.07).

Patients with advanced liver disease are more likely to have abnormalities in gut motility compared to those with lower Child-Pugh scores (a scoring system that measures the severity of liver disease). These abnormalities include disruptions in the MMC and an increase in the frequency of clustered contractions — both of which may promote bacterial stasis and SIBO — and occur in 31–68% of patients. SIBO does not appear to be an independent risk factor for liver injury, however.

Recent animal studies have shown that acute pancreatitis can alter the MMC, and that acute necrotizing pancreatitis disturbs the jejunal MMC, leading to SIBO. A study of 35 patients with chronic pancreatitis and pancreatic insufficiency found that 34% had SIBO, as determined by a glucose breath test.

Chronic alcohol use may also predispose patients to SIBO. A study from Sweden compared 22 alcoholics with epigastric pain and nausea to 12 nonalcoholic patients with dyspeptic symptoms. Using both gastric and duodenal biopsies and aspirates, bacterial overgrowth was identified in 90% of alcoholics compared to 50% of controls (P<.01). Of note, 7 of the 12 control patients had used acid suppressants, which may explain the high rate of bacterial overgrowth in the control population.

Finally, antibiotics can alter the normal balance of gut flora, leading to changes in the bacterial population within the GI tract. No prospective studies in this area were identified in the literature.

Symptoms of SIBO

Symptoms of SIBO are nonspecific and include:

• Bloating
• Abdominal distension
• Abdominal pain or discomfort
• Diarrhea
• Fatigue
• Weakness
• Flatulence

The frequency and severity of symptoms likely reflect both the degree of bacterial overgrowth and the extent of mucosal inflammation. However, symptoms may also reflect the underlying cause of SIBO (for example, small bowel dysmotility). Other symptoms can reflect complications of SIBO, including malabsorption, nutritional deficiencies, and metabolic bone disorders.

The nonspecific nature of these complaints makes SIBO difficult to distinguish clinically from other disease entities such as IBS, lactose intolerance, or fructose intolerance. No study has evaluated the specificity of these symptoms. Therefore, objective testing is recommended rather than relying on symptoms alone.

Complications of SIBO

Complications of SIBO range from mild — including diarrhea and minimal vitamin deficiencies — to severe, including malabsorption and neuropathies (nerve damage) due to fat-soluble vitamin deficiencies. The nutritional consequences of SIBO result from maldigestion and malabsorption of nutrients in the intestinal lumen. This occurs secondary to microscopic damage to the small intestinal mucosa, which diminishes the absorptive capacity of the microvilli.

Here is how the major complications develop:

Fat malabsorption occurs as a result of bacterial deconjugation of bile salts. Free bile acids are toxic to the intestinal mucosa, resulting in mucosal inflammation and malabsorption. Deconjugated bile salts are reabsorbed in the jejunum rather than the ileum, leading to impaired micelle formation, fat malabsorption, and deficiencies in the fat-soluble vitamins A, D, E, and K. Fortunately, symptoms rarely develop — but in severe cases, patients can experience:

• Night blindness (vitamin A deficiency)
• Osteomalacia (softening of the bones) and tetany (muscle spasms) due to hypocalcemia (low calcium, from vitamin D deficiency)
• Prolonged prothrombin times (a bleeding risk, from vitamin K deficiency)
• Neuropathy, retinopathy, and impairments in T-cell function

Carbohydrate malabsorption develops as a result of premature breakdown of sugars by bacteria, combined with decreased disaccharidase activity secondary to disruption of the intestinal brush border. Protein malabsorption can occur because of digestion of protein by bacteria, whereas protein-losing enteropathies can develop as a result of mucosal damage.

A common complication of bacterial overgrowth is cobalamin (vitamin B12) deficiency. Patients with normal intestinal enteric flora rely on gastric intrinsic factor to bind to vitamin B12 to permit absorption in the ileum. An animal model of SIBO demonstrated that bacteria take up the vitamin B12-intrinsic factor complex, depriving the host of this essential nutrient. Other nutritional complications include iron deficiency, folate excess (because bacteria can produce folate), hypoproteinemia/hypoalbuminemia (low protein levels in the blood), and decreased xylose absorption (a marker of impaired nutrient absorption).

How Is SIBO Diagnosed?

The diagnosis of SIBO is controversial. There is substantial disagreement in the medical literature regarding which test is most appropriate in either the clinical or research setting. Two tests are commonly employed: bacterial culture and breath tests.

Bacterial culture. The most direct method of assessing the bacterial population is to perform anaerobic and aerobic colony counts of small bowel luminal contents. However, this method has several technical hurdles:

1. The small bowel must be intubated. In years past, a long tube was passed under fluoroscopic guidance and fluid aspirated through the tube. Today, few diagnostic centers use this cumbersome, time-consuming method. Instead, a catheter is passed into the distal duodenum through an endoscope, and fluid is aspirated for culture. The cost of endoscopy, as well as its low but measurable risk, makes this approach less than ideal.
2. Many bacterial species do not grow in routine culture media, so quantitative culture may underestimate the bacterial population.
3. There are multiple problems inherent in performing this procedure, including contamination of the endoscope and catheter as the instrument is passed through the GI tract, difficulty aspirating a sufficient sample, and insufflation of air into the lumen, which prevents accurate sampling.
4. Regardless of which approach is used, prompt processing of the sample is essential for accurate results.

Breath tests. Breath testing is less invasive and more readily available. Two types are used: the glucose breath test and the lactulose breath test. These tests measure hydrogen and/or methane gas in the breath after a patient ingests a sugar solution. When bacteria in the small intestine ferment the sugar, they produce gas that is absorbed into the bloodstream and exhaled in the breath. The accuracy of these tests, however, depends on the sugar used, the timing of measurements, and the criteria for a positive result — which may explain the widely varying prevalence rates reported across different studies (0% to 84% in different populations).

Treatment Options

The original review notes that although a number of diagnostic tests are available, the optimal treatment regimen remains elusive. However, several antibiotic options are identified in the literature and in the review's own search methodology, including:

• Rifaximin — a nonabsorbable antibiotic that works locally in the gut
• Tetracycline
• Metronidazole
• Ciprofloxacin
• Amoxicillin/clavulanate
• Probiotics — which may help restore the normal balance of gut flora

The evidence referenced throughout the review supports the effectiveness of antibiotic treatment. For example, 75% of diabetic patients with chronic diarrhea and SIBO had significant improvement in symptoms after antibiotic treatment, and all celiac disease patients with SIBO noted resolution of symptoms after being treated for bacterial overgrowth. Additionally, the microscopic mucosal changes seen in elderly patients with SIBO (blunted villi, thinned mucosa, increased intraepithelial lymphocytes) reversed with antibiotic treatment.

The authors also note that recurrent antibiotic use can itself alter the normal balance of gut flora, and they emphasize that more research is needed to determine the optimal treatment approach, including the duration of therapy and the role of antibiotic resistance.

Study Limitations

This review article has several important limitations that patients should understand:

• No incidence data: The authors could not identify any study evaluating the incidence of SIBO in healthy volunteers, so it is impossible to know how many new cases develop each year.
• Conflicting prevalence rates: The widely varying prevalence rates across studies (from 0% to 84%, depending on the population and test used) reflect differences in diagnostic methods, study populations, and criteria for positivity — not necessarily true differences in disease frequency.
• Small study sizes: Many of the studies cited enrolled small numbers of patients (for example, 15 celiac patients, 22 renal failure patients, 35 pancreatitis patients), which limits the strength of their conclusions.
• Conflicting results on acid suppression: Studies of H2RAs and PPIs produced disparate results, and the authors acknowledge these may reflect a true medication effect or, alternatively, small sample sizes and differences in assay techniques.
• The IBS controversy: The relationship between IBS and SIBO remains hotly debated, with some studies showing 65–84% prevalence in IBS patients and others showing 0–10%. The review does not resolve this controversy.
• No prospective antibiotic studies: The literature search found no prospective studies evaluating how antibiotic use affects the development of SIBO.
• Only three databases searched: The review used Ovid MEDLINE (1966 to December 2006, English language only) and PubMed, and only published manuscripts were included — abstracts were excluded.

Recommendations for Patients

Based on this comprehensive review, here are practical takeaways for patients and their caregivers:

1. If you have chronic diarrhea, bloating, or unexplained weight loss, talk to your doctor about SIBO. These symptoms are nonspecific, but the review found SIBO in 33% of patients with chronic diarrhea and in 43% of diabetic patients with chronic diarrhea. Objective testing is recommended rather than guessing based on symptoms alone.
2. If you have IBS, be aware that SIBO may be a factor — but the evidence is mixed. Some studies found SIBO in up to 84% of IBS patients, while others found none. If your IBS symptoms have not responded to standard treatments, asking your doctor about breath testing for SIBO may be reasonable.
3. Antibiotic treatment can be effective. The evidence consistently shows that treating SIBO with antibiotics (such as rifaximin, tetracycline, metronidazole, ciprofloxacin, or amoxicillin/clavulanate) resolves symptoms in many patients — including 75% of diabetics with chronic diarrhea and 100% of the celiac patients in the study.
4. If you take acid-suppressing medications long-term, discuss the risks with your doctor. Studies showed SIBO developed in 53% of patients on omeprazole (a proton pump inhibitor), compared to 17% on cimetidine (an H2RA). This doesn't mean you should stop your medication — but it's worth a conversation if you experience new digestive symptoms.
5. If you've had GI surgery, you may be at higher risk. Blind loop surgeries (Billroth II, Roux-en-Y), ileocecal valve resection, and jejunoileal bypass all increase the risk of SIBO. Crohn's patients who had ileocecal valve resection saw their SIBO prevalence jump from 18% to 30%.
6. Older adults and those with motility disorders should be especially vigilant. Prevalence rates in older adults ranged from 14.5% to 15.6%, and rose to 33% in disabled older adults. Conditions like gastroparesis, scleroderma, cirrhosis, and chronic renal failure all increase risk.
7. Know the complications. Untreated SIBO can lead to deficiencies in fat-soluble vitamins (A, D, E, K), vitamin B12 deficiency, iron deficiency, protein loss, and bone disorders. If you have SIBO, ask your doctor about checking your vitamin and mineral levels.

Frequently Asked Questions

What is SIBO?

SIBO is small intestinal bacterial overgrowth, a condition diagnosed when bacteria in the small intestine exceed normal levels, generally more than 10^5 to 10^6 organisms per milliliter. Normally, fewer than 10^3 organisms are present. Both the number and type of bacteria matter for symptoms like bloating or diarrhea.

What are common symptoms of SIBO?

Symptoms are nonspecific and may include bloating, abdominal distension, abdominal pain or discomfort, diarrhea, fatigue, weakness, and flatulence. Their severity likely reflects the degree of bacterial overgrowth and mucosal inflammation, as well as the underlying cause. Because symptoms are nonspecific, objective testing is recommended instead of relying on symptoms alone.

Who is at risk for SIBO?

Risk groups include older adults, people with irritable bowel syndrome (evidence mixed), diabetes with chronic diarrhea, long-standing celiac disease, chronic renal failure, advanced liver disease, chronic pancreatitis, alcohol use, and those with structural GI abnormalities or prior surgeries like blind loop procedures or ileocecal valve resection. Reduced stomach acid from aging, H. pylori, or acid-suppressing medications also increases risk.

How is SIBO diagnosed?

Two tests are commonly used: bacterial culture of small bowel fluid, obtained through an endoscope, and breath tests using glucose or lactulose. Breath tests measure hydrogen or methane gas after drinking a sugar solution. Accuracy depends on the sugar used, timing, and criteria for a positive result, which explains varying prevalence rates across studies.

What treatments are available for SIBO?

Antibiotic options include rifaximin, tetracycline, metronidazole, ciprofloxacin, and amoxicillin/clavulanate. Probiotics may also help restore normal gut flora. Evidence supports effectiveness; for instance, 75% of diabetic patients with chronic diarrhea and SIBO improved after antibiotics, and all celiac disease patients with SIBO had symptom resolution. More research is needed on optimal duration and antibiotic resistance.

If I have IBS, could it be SIBO?

The relationship is debated. Some studies found abnormal breath tests suggestive of SIBO in 65% to 84% of IBS patients, while others found none or only 10%. If your IBS symptoms haven't responded to standard treatments, asking your doctor about breath testing for SIBO may be reasonable. Objective testing is recommended rather than relying on symptoms.

Can SIBO cause complications?

Yes. SIBO can cause malabsorption of fat, carbohydrates, and protein. Complications may include deficiencies of vitamins A, D, E, K, vitamin B12, and iron, leading to night blindness, osteomalacia, tetany, prolonged prothrombin times, neuropathy, and retinopathy. Untreated SIBO may also cause protein-losing enteropathy and low blood protein levels.

Can a second opinion change my SIBO treatment plan?

A second opinion can change your SIBO treatment plan because the diagnosis is often controversial and diagnostic test results vary widely. Breath tests and small bowel cultures produce inconsistent results, and symptoms such as bloating and diarrhea overlap with IBS and other conditions. Antibiotic treatment with rifaximin or other agents resolves symptoms in many patients, but the optimal regimen and duration remain unclear. A second opinion can clarify whether your testing was adequate, whether antibiotics are truly needed, and which alternative approaches might help. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original article title: Small Intestinal Bacterial Overgrowth 2007

Authors: Andrew C. Dukowicz, MD; Brian E. Lacy, PhD, MD; and Gary M. Levine, MD

Published in: Gastroenterology & Hepatology, Volume 3, Issue 2, February 2007, pages 112–116

Author affiliations: Section of Gastroenterology and Hepatology, Dartmouth-Hitchcock Medical Center and Dartmouth Medical School, Lebanon, New Hampshire

This patient-friendly article is based on peer-reviewed research. It is intended for educational purposes and should not replace professional medical advice. Patients should consult their healthcare provider for diagnosis and treatment of any medical condition.