Meticulous examination focused on the patient problem may yield a causative diagnosis of peritonitis due to perforated gastric or duodenal ulcer, perforated appendicitis o diverticulitis, suggested on the basis of wall thickening, fluid accumulation, inflammatory mass, thickening of the gallbladder, hyperechogenicity of the right anterior extrarenal tissue (renal rind sign) and free intraperitoneal gas confined to the fissure for ligamentum teres