These symptoms include the acid-induced erosion of the esophagus and enamel, halitosis, malnutrition, severe weight loss and an unquenchable appetite. Little comprehensive data regarding rumination syndrome in otherwise healthy individuals exists because most people are private about their illness and are often misdiagnosed due to the number of symptoms and the clinical similarities between rumination syndrome and other disorders of the stomach and esophagus, such as gastroparesis and bulimia nervosa. Like related gastrointestinal disorders, rumination can adversely affect normal functioning and the social lives of individuals. Rumination syndrome presents itself in a variety of ways, with especially high contrast existing between the presentation of the typical adult patient without a mental disability and the presentation of an adult with a mental disability.
It is increasingly being diagnosed in a greater number of otherwise healthy adolescents and adults, though there is a lack of awareness of the condition by doctors, patients and the general public. The disorder has been historically documented as affecting only infants, young children, and people with cognitive disabilities (the prevalence is as high as 10% in institutionalized patients with various mental disabilities). There is no retching, nausea, heartburn, odour, or abdominal pain associated with the regurgitation, as there is with typical vomiting, and the regurgitated food is undigested. Rumination syndrome, or merycism, is a chronic motility disorder characterized by effortless regurgitation of most meals following consumption, due to the involuntary contraction of the muscles around the abdomen.
The "spikes" are characteristic of the abdominal wall contractions responsible for the regurgitation in rumination. A postprandial manometry of a patient with rumination syndrome showing intra-abdominal pressure.