Functional dyspepsia is mainly caused by gastric and duodenal dysfunction.
1. Gastrointestinal dyskinesia: delayed gastric emptying and malfunction of motor coordination.
2. Visceral sensory hypersensitivity: the sensory capacity of the stomach is significantly lower than normal.
3. Decreased diastolic function of the fundus of the stomach to tolerate food: mainly manifested as early satiety.
4. Increased gastric acid secretion: highly sensitive to dilatation and acid stimulation.
5. Psychosocial factors: mostly accompanied by varying degrees of anxiety, depression, insomnia, and poor concentration.
Functional dyspepsia is usually a group of clinical syndromes without organic disease, mainly manifested by fullness, early satiety, lack of appetite, nausea, usually persistent or recurrent, mostly induced by psychogenic factors.