Evaluation of nausea and vomiting.

A comprehensive history and physical examination can often reveal the cause of nausea and vomiting, making further evaluation unnecessary. Acute symptoms generally are the result of infectious, inflammatory, or iatrogenic causes. Most infections are self-limiting and require minimal intervention; iatrogenic causes can be resolved by removing the offending agent. Chronic symptoms are usually a pathologic response to any of a variety of conditions. Gastrointestinal etiologies include obstruction, functional disorders, and organic diseases. Central nervous system etiologies are primarily related to conditions that increase intracranial pressure, and typically cause other neurologic signs. Pregnancy is the most common endocrinologic cause of nausea and must be considered in any woman of childbearing age. Numerous metabolic abnormalities and psychiatric diagnoses also may cause nausea and vomiting. Evaluation should first focus on detecting any emergencies or complications that require hospitalization. Attention should then turn to identifying the underlying cause and providing specific therapies. When the cause cannot be determined, empiric therapy with an antiemetic is appropriate. Initial diagnostic testing should generally be limited to basic laboratory tests and plain radiography. Further testing, such as upper endoscopy or computed tomography of the abdomen, should be determined by clinical suspicion based on a complete history and physical examination.