NAUSEA AND VOMITING



Nausea and vomiting are often associated with abdominal pain, and their presence may provide clues to the underlying diagnosis. Vomiting most commonly occurs with obstruction and distention of the stomach or intestine (pyloric stenosis, small bowel obstruction), motility disorders (diabetic gastroparesis), or irritation and inflammation of the peritoneum. In these disorders, vagal afferents are thought to stimulate the medullary chemore-ceptor trigger zones, which in turn induce vom­iting. Drugs and gastric mucosal irritants may also induce vomiting via this pathway. Other disor­ders associated with vomiting include increased intracranial pressure, psychogenic vomiting, hy­persecretion of gastric acid (Zollinger-EUison syn­drome), and the early morning vomiting of alco­holics, pregnant women, and uremics.