FIGURE 1.

Excessive activation of the hypothalamus‐pituitary‐adrenal axis and the autonomic nervous system, as well as partial loss of intestinal neurons and imbalance of the intestinal flora after CNS injury, changes the internal environment, which can lead to increased intestinal permeability furtherly. These changes can lead to poor outcomes such as intestinal bacteria translocation, gastrointestinal dysfunction, and aggravation of brain injury. Following this, secondary infections, especially pulmonary and urinary tract infections, can occur. Nervous dysfunction and intestinal flora imbalances also result in intestinal immune imbalances, increasing intestinal permeability and worsening the patient's outcome