Ophthalmic Manifestations of SIBO
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Small Intestinal Bacterial Overgrowth (SIBO) is a disease entity that is associated with vitamin deficiencies leading to nutritional optic neuropathies. Commonly, SIBO leads to deficiencies in B12, folate, and other vitamins and minerals. [1][2]
Disease Entity
SIBO is a well described cause of nutritional deficiency secondary to E. coli, Enterococcus, Klebsiella Pneumonia, Proteus mirabilis and other organisms.[1][2] Common initial symptoms include dyspepsia, abdominal pain , nausea and vomiting.[1][2] A major pre-disposing risk factor for SIBO is Roux en-y gastric bypass surgery.[1][2] Optic neuropathy secondary to nutritional deficiency often manifests as bilateral symmetrical visual impairment, centrocecal scotoma, and dyschromatopsias.[3][4]
Etiology
The etiology of nutritional optic neuropathy secondary to SIBO is considered to be due to malabsorption of essential nutrients (Thiamine, Pyridoxine, Folate, B12) secondary to bacterial load parasitism.
Risk Factors
Risk factors include history of bariatric surgery creating a blind loop of bowel (i.e. Roux en-Y) and a diet high in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP)[1]
Pathophysiology
The mechanism of nutritional optic neuropathy is not well described. It is thought that vitamin deficiencies disrupt oxidative phosphorylation and lead to oxidative stress.[4]
Diagnosis
The diagnosis of Optic Neuropathy requires a nutritional optic neuropathy in the setting of SIBO without other known causes.
SIBO can be diagnosed using a Hydrogen/Lactose breath test. This test measures the amount of Methane/Hydrogen produced after the consumption of a known amount of sugar. [1][2]
Testing for Thiamine, Pyridoxine, Folate, and B12 levels is required and deficiencies in one or all of these vitamins may suggest nutritional optic neuropathy.[3][4] Low Folate and B12 levels may manifest as elevations in methylmalonic acid and homocysteine. [3][4]
Management
Referral to the patient's operating surgeon or a gastrointestinal doctor is recommended. Often antibiotics in the form of Rifaximin are highly effective and lead to a decrease in abdominal symptoms.[1][2] Following this with a low FODMAP diet will inhibit the bacteria from over-proliferating.[1][2] Once the bacteria have been curbed, replenishing the vitamins through oral or intramuscular means is recommended.[5]
References
- Achufusi TGO, Sharma A, Zamora EA, Manocha D. Small Intestinal Bacterial Overgrowth: Comprehensive Review of Diagnosis, Prevention, and Treatment Methods. Cureus. 2020 Jun 27;12(6):e8860. doi: 10.7759/cureus.8860. PMID: 32754400; PMCID: PMC7386065.
- Sachdev AH, Pimentel M. Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance. Ther Adv Chronic Dis. 2013 Sep;4(5):223-31. doi: 10.1177/2040622313496126. PMID: 23997926; PMCID: PMC3752184.
- Ata F, Bint I Bilal A, Javed S, Shabir Chaudhry H, Sharma R, Fatima Malik R, Choudry H, Bhaskaran Kartha A. Optic neuropathy as a presenting feature of vitamin B-12 deficiency: A systematic review of literature and a case report. Ann Med Surg (Lond). 2020 Nov 5;60:316-322. doi: 10.1016/j.amsu.2020.11.010. PMID: 33204422; PMCID: PMC7653199.
- Roda, M., di Geronimo, N., Pellegrini, M. and Schiavi, C., 2020. Nutritional Optic Neuropathies: State of the Art and Emerging Evidences. Nutrients, 12(9), p.2653.
- Bensky, M., Ayalon-Dangur, I., Ayalon-Dangur, R., & Naamany, E. (2019). Comparison of sublingual vs. intramuscular administration of vitamin B12 for the treatment of patients with vitamin B12 deficiency. Drug Delivery And Translational Research, 9(3), 625-630. doi: 10.1007/s13346-018-00613-y
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Achufusi TGO, Sharma A, Zamora EA, Manocha D. Small Intestinal Bacterial Overgrowth: Comprehensive Review of Diagnosis, Prevention, and Treatment Methods. Cureus. 2020 Jun 27;12(6):e8860. doi: 10.7759/cureus.8860. PMID: 32754400; PMCID: PMC7386065.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Sachdev AH, Pimentel M. Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance. Ther Adv Chronic Dis. 2013 Sep;4(5):223-31. doi: 10.1177/2040622313496126. PMID: 23997926; PMCID: PMC3752184.
- ↑ 3.0 3.1 3.2 Ata F, Bint I Bilal A, Javed S, Shabir Chaudhry H, Sharma R, Fatima Malik R, Choudry H, Bhaskaran Kartha A. Optic neuropathy as a presenting feature of vitamin B-12 deficiency: A systematic review of literature and a case report. Ann Med Surg (Lond). 2020 Nov 5;60:316-322. doi: 10.1016/j.amsu.2020.11.010. PMID: 33204422; PMCID: PMC7653199.
- ↑ 4.0 4.1 4.2 4.3 Roda, M., di Geronimo, N., Pellegrini, M. and Schiavi, C., 2020. Nutritional Optic Neuropathies: State of the Art and Emerging Evidences. Nutrients, 12(9), p.2653.
- ↑ Bensky, M., Ayalon-Dangur, I., Ayalon-Dangur, R., & Naamany, E. (2019). Comparison of sublingual vs. intramuscular administration of vitamin B12 for the treatment of patients with vitamin B12 deficiency. Drug Delivery And Translational Research, 9(3), 625-630. doi: 10.1007/s13346-018-00613-y
