++
What key clinical entities must be considered in the initial assessment of a hospitalized patient with acute nausea and vomiting?
What is the clinical diagnostic approach to the inpatient with nausea and vomiting?
How should patients with nausea and vomiting in the hospital setting be treated?
++
++
Nausea and vomiting are common and uncomfortable symptoms with a large number of underlying causes. Nausea is a subjective sensation, usually experienced in the epigastrium or throat when vomiting is imminent (although vomiting may or may not occur). Nausea may be followed by retching, which is repetitive active contraction of the abdominal musculature. Retching may occur in isolation without the forceful expulsion of gastric contents. In contrast, vomiting is a highly physical event that results in the evacuation of gastric contents. This should be distinguished from regurgitation, which is the effortless reflux of gastric or esophageal contents to the hypopharynx.
++
Studies have suggested that the act of vomiting is controlled by a central neurologic center. Borison and colleagues have studied the mechanism of vomiting in cats and found that vomiting can be induced by electrical stimulation of a “vomiting center” located in the dorsal portion of the medulla. These studies, however, have not yet been repeated in human subjects. Experimental studies have also suggested that a chemoreceptor trigger zone (CTZ) activates the vomiting center when stimulated.
++
Emetic stimuli can cause vomiting by one of two mechanisms. ...