This conceptual note interprets recent findings on hypothyroidism, autoimmune thyroiditis, small intestinal bacterial overgrowth (SIBO), and duodenal microbiome alteration through the Universal Resonance Model (URM). Rather than treating hypothyroidism and SIBO only as separate diagnoses, the note frames the thyroid–gut relationship as a coupled physiological system involving thyroid hormone status, gastrointestinal motility, microbial configuration, absorption, and treatment stability. The clinical implication is not universal SIBO screening in all patients with hypothyroidism. Instead, persistent gastrointestinal symptoms, malabsorption, or unstable levothyroxine response may deserve attention as possible system-level signals. This work belongs to the URM / Dynamic Medicine series and extends the concept of disease as a dynamic, state-dependent process to the thyroid–gut axis.
Anita Domargård (Wed,) studied this question.