15 - Nausea and Vomiting

Abstract

Nausea represents a sensation of impending vomiting and can be associated with additional symptoms including salivation, perspiration, and lightheadedness. Vomiting consists of the retrograde expulsion of gastric or proximal intestinal content through the mouth and can relieve nausea in some settings. Vomiting needs to be distinguished from regurgitation and rumination. Perception of nausea requires intact supratentorial neural circuits, whereas vomiting is mediated through brainstem centers in response to peripheral and central inputs. The initial assessment of a patient with nausea and vomiting determines whether emergent resuscitation is needed because of dehydration and electrolyte imbalance and whether a woman of childbearing age is pregnant. Important causes to consider include gastric or intestinal obstruction, systemic and intra-abdominal inflammation or infections, drugs and toxins, neurologic and vestibular etiologies, postoperative nausea and vomiting, and vascular catastrophe, including ischemic bowel disease. Urgent evaluation with routine blood tests and drug or toxin levels can be complemented with cross-sectional imaging and, in some cases, EGD and barium radiography. Chronic nausea and vomiting can arise from pregnancy, functional disorders, and motility disturbances, including gastroparesis. Stereotypical episodes of nausea and vomiting with symptom-free intervals between episodes are clues to the diagnosis of cyclic vomiting syndrome or cannabinoid hyperemesis syndrome. When the etiology is identified, specific therapy can be offered. Symptomatic management with antiemetics (phenothiazines, benzamides, serotonin receptor antagonists) can be of value as investigation proceeds, even if a specific mechanism is not identified. Complications of vomiting include electrolyte disturbance, Mallory Weiss syndrome, nutritional deficiencies, aspiration pneumonia, and rarely, esophageal rupture (Boerhaave syndrome).