Small intestinal bacterial overgrowth as a cause of protracted wound healing and vitamin D deficiency in a spinal cord injured patient with a sacral pressure sore: a case report

Background: Pressure sores are sometimes refractory to treatment, often due to malnutrition. Small intestinal bacterial overgrowth (SIBO) obstructs absorption in the digestive tract and causes malnutrition. However, little is known about the association between pressure sore wound healing and SIBO. Here, we report a case of a patient with a refractory sacral pressure sore and SIBO.

Case presentation: A 66-year-old woman who was spinal cord injured 14 years before visiting our hospital presented with the chief complaint of a sacral pressure sore, 10.0 × 6.5 cm in size, which was refractory to treatment. Physical examination showed abdominal distension and emaciation, with a body mass index of 15. Further examination revealed elevated serum alkaline phosphatase (1260 U/L), bilateral tibial fracture, multiple rib fracture, and osteoporosis. We diagnosed the patient with osteomalacia with vitamin D deficiency. Despite oral supplementation, serum levels of calcium, phosphorous, and vitamin D remained low. Also, despite concentrative wound therapy for the sacral pressure sore by plastic surgeons, no wound healing was achieved. Due to a suspicion of disturbances in nutrient absorption, we performed bacterial examination of collected gastric and duodenal fluid, which showed high numbers of bacteria in gastric content (10⁴ E. coli, 10⁵ Streptococcus species, and 10⁵ Neisseria species) and duodenal content (10⁶ E. coli, 10⁴ Candida glabrata). Therefore, we diagnosed the patient with SIBO and started selective decontamination of the digestive tract using polymyxin B sulfate and amphotericin B. After starting treatment for SIBO, the sacral pressure sore began to heal and was nearly healed after 285 days. The patient's serum levels of calcium, phosphorous, vitamin D, and other fat-soluble vitamins also gradually increased after starting treatment for SIBO.

Conclusion: We report a case of a patient with a refractory sacral pressure sore that healed after starting treatment for SIBO. We conclude that SIBO may be an overlooked cause of malnutrition and poor wound healing in patients with chronic pressure sores.

Keywords: Case report; Malnutrition; Pressure wound; Small intestinal bacterial overgrowth; Spinal cord injury; Wound healing.