IBS, SIBO & IMO in MECFS. When The Gut Microbiome Goes Wrong

The Basics

IBS - Irritable Bowel Syndrome

SIBO - Small Intestine Bacterial Overgrowth

IMO - Intestinal Methanogen Overgrowth

ME - Myalgic Encephalomyelitis

IBS & SIBO are both more common in ME

Gut Disturbances like SIBO, IMO & IBS can cause increased inflammation and mast cell activation.

SIBO & IMO can be diagnosed by breath testing or endoscopic sampling.

SIBO & IMO can be effectively treated with antibiotic therapy. Alternative therapies also exist.

We do not know the cause of ME, gut disturbances are an important puzzle piece but only one part of this multisystemic illness.

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Irritable Bowel Syndrome (IBS)

Is a condition that causes gastrointestinal and systemic symptoms such as

Abdominal Pain

Gas

Bloating

Cramping

Nausea

Diahrea

Constipation

Fatigue

Brain Fog

Diagnosis is made based on symptoms and ruling out other more dangerous conditions such as Inflammatory Bowel Disease (IBD) like Crohn's Disease and Ulcerative Colitis. Unlike IBD, IBS does not show any abnormalities in imaging and blood testing.

If the primary symptom is diarrhea this is sometimes called IBS-D and if constipation is more prominent it is called IBS-C.

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Treating IBS

There are a number of treatments for IBS

Dietary

A low FODMAP diet may be used to control symptoms.

Therapy

Some patients find CBT or autonomic nervous system interventions helpful for managing symptoms.

Antibiotics

Rifaxamin is approved to treat IBS in the US. Antibiotic treatment of IBS works on the theory that bacterial overgrowth is causing the IBS symptoms.

Other

Fecal matter transplant is being investigated as a treatment.

Treatments for IBS can also be used to manage symptoms of SIBO.

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Small Intestine Bacterial Overgrowth (SIBO)

Is a condition where too much bacteria is growing in the small intestine. It causes symptoms extremely similar to IBS and can be diagnosed by taking a sample of fluid from the small intestine through endoscopy or by breath testing for hydrogen and methane gas.

When there is a high amount of methane gas-producing organisms or methanogens, this is sometimes referred to as Intestinal Methanogen Overgrowth or IMO.

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"Leaky Gut"

SIBO can cause intestinal permeability or "leaky gut" which can lead to pro-inflamatory mediators entering the bloodstream. This can lead to increased fatigue and chronic pain.

Mass Cell Activation

Because hydrogen and methane produced in SIBO are mast cell activators, treating SIBO can often have beneficial effects on mast cell activation syndrome (MCAS) a common commorbidity of MECFS and Long Covid. Additionally, DAO an enzyme that breaks down histamine is produced in the small intestine so gut disturbances can increase histamine intollence.

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SIBO & IMO Treatment

Antibiotic therapy is the standard treatment for SIBO. The primary antibiotic used is Rifaxamin, this is because it is very poorly absorbed by the body allowing it to work exclusively on the intestines. In IMO the combination of Rifaxamin and Neomycin is often used. Other antibiotics such as Metronidazole have also been trialed successfully.

The standard course of antibiotics is 14 days however relapse is common and patients may require retreatment. Always follow the dosing guidelines of antibiotics exactly as your doctor prescribes to reduce risk of antibiotic resistance.

Antibiotic treatment can be expensive, and doctors may prescribe alternatives based on what insurance will cover.

Fecal matter transplant is also being studied in SIBO.

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Alternative Medicine For SIBO

Not all patients tolerate antibiotic therapy. For those who don't herbal antimicrobials were shown in one study using the supplements Candibactin-AR & BR to be as effective as rifaxamin.

Some probiotics have also shown preliminary positive results. Probiotics may be used after antibiotics to help rebuild a healthy microbiome. Probiotic strains must be carefully chosen as some can make SIBO worse by adding to the overgrowth.

Stomach acid concentration may be increased using supplements like betadine hydrochloride, but this is also not studied.

An elemental diet may also be used in an attempt to starve the bacteria. Strict diets for IBS and SIBO should not be tried without physican supervision to avoid nutritional deficits.

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SIBO & MECFS

Preliminary research suggests SIBO is more prevalent in MECFS as are alterations in the microbiome such as lower concentrations of bifidobacteria and higher levels of streptococcus and enterococcus bacteria. A 2001 Belgian study found that over 80% of patients meeting Fukunda Criteria for ME had gastrointestinal disturbances (MEPedia 2023).

While the relation between SIBO/IBS/Gut Health and ME is important it should be remembered that ME is a complex multisystemic illness that cannot be reduced to a single axis of dysfunction. Knowing that gut dysfunction impacts ME is very different to knowing that gut dysfunction causes ME. We do not know the cause of ME so for now we must settle for treating symptoms and dysfunctions as they arise.

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Practicalities of SIBO & ME

If you have IBS symptoms and ME I highly recommend getting as much investigational testing as you can access with breath testing for SIBO falling on that list. If you are positive for SIBO treating it may cause significant improvement.

Treatment is only indicated in those with a positive test result for SIBO. Antibiotic use comes with many side effects and can cause c diff diahrea or antibiotic resistance so should not be used outside of its indications.

Treatment with antibiotics can be expensive so work with your doctor to find options you can afford.

If you do not tolerate antibiotics an herbal treatment route can be tried.

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Gut dysfunction in ME is a pain in the ass. The Gut Microbiome is a poorly understood area of human biology but preliminary research shows that it can have impacts on almost every part of our health.

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Irritable Bowel Syndrome or IBS describes a wide range of symptoms including:

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Abdominal Pain

Gas

Bloating

Cramping

Constipation

Diarrhea

Nausea

Fatigue

BrainFog

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IBS can be treated with a low FODMAP diet and some people also find autonomic nervous system interventions helpful in managing IBS symptoms.

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In some cases IBS may be caused by SIBO or Small Intestine Bacterial Overgrowth or methane dominant SIBO known as IMO or Intestinal Methanogen Overgrowth.

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These disorders can be tested for with breath testing or with endoscopic sampling and culture.

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In Myalgic Encephalomyelitis ME/CFS MECFS gastrointestinal disturbances are incredibly common. This may be due to immunocompromization, gastroparesis, infections, enterovirus infection of the gut, or other unknown causes.

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While testing for and treating SIBO and related issues is not a cure for ME, resolving these issues can provide symptom relief and increase functionality for some.

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SIBO can be treated with antibiotics or with herbal medications. Probiotics can be helpful in restoring a healthy gut microbiome after antibiotics but caution should be used as some probiotics can make SIBO worse.

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There is no magic bullet for complex Chronic Illness and Myalgic E.

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However, good understanding of the commorbid conditions and symptom management options can greatly improve quality of life while we wait on research to Cure MECFS.

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