Nausea refers to the imminent desire to vomit and often precedes or accompanies vomiting. Vomiting refers to the forceful expulsion of gastric contents through the mouth. Retching refers to labored rhythmic respiratory activity that precedes emesis. Regurgitation refers to the gentle expulsion of gastric contents in the absence of nausea and abdominal diaphragmatic muscular contraction. Rumination refers to the regurgitation, rechewing, and reswallowing of food from the stomach.
Gastric contents are propelled into the esophagus when there is relaxation of the gastric fundus and gastroesophageal sphincter followed by a rapid increase in intraabdominal pressure produced by contraction of the abdominal and diaphragmatic musculature. Increased intrathoracic pressure results in further movement of the material to the mouth. Reflex elevation of the soft palate and closure of the glottis protect the nasopharynx and trachea and complete the act of vomiting. Vomiting is controlled by two brainstem areas, the vomiting center and chemoreceptor trigger zone. Activation of the chemoreceptor trigger zone results in impulses to the vomiting center, which controls the physical act of vomiting.
Nausea and vomiting are manifestations of a large number of disorders (Table 38-1).
TABLE 38-1CAUSES OF NAUSEA AND VOMITING |Favorite Table|Download (.pdf) TABLE 38-1CAUSES OF NAUSEA AND VOMITING
|Intraperitoneal ||Extraperitoneal ||Medications/Metabolic Disorders |
Superior mesenteric artery syndrome
Altered sensorimotor function
Chronic idiopathic nausea
Cyclic vomiting syndrome
Cannabinoid hyperemesis syndrome
Anorexia and bulimia nervosa
Thyroid and parathyroid disease
The history, including a careful drug history, and the timing and character of the vomitus can be helpful. For example, vomiting that occurs predominantly in the morning is often seen in pregnancy, uremia, and alcoholic gastritis; feculent emesis implies distal intestinal obstruction or gastrocolic fistula; projectile vomiting suggests increased intracranial pressure; vomiting during or shortly after a meal may be due to psychogenic causes or peptic ulcer disease. Associated symptoms may also be helpful: vertigo and tinnitus in Ménière’s disease, relief of abdominal pain with vomiting in peptic ulcer, and early satiety in gastroparesis. Plain radiographs can suggest diagnoses such as intestinal obstruction. The upper GI series assesses motility of the proximal GI tract as well as the mucosa. Other studies may be indicated, such as gastric emptying scans (diabetic gastroparesis) and CT scan of the brain.