The physical examination should focus on assessing the severity of dehydration. A dry mouth, decreased axillary sweat, and decreased urine output indicate mild dehydration. An orthostatic fall in blood pressure, skin tenting, and sunken eyes indicate moderate dehydration. Severe dehydration manifests as hypotension with tachycardia, confusion, and frank shock. A rectal examination always should be performed to directly visualize the stool, test occult blood, and palpate the rectal mucosa for any lesions. Orthostatic changes, fever, and signs of peritoneal irritation indicate a malignant course secondary to invasive disease.