Viral syndromes, 474 –475 Viremia, 501 t Vision, double, 1385 Visual disturbances causes, 189 t common conditions that cause, 189 t diagnostic approach to, 192 f differential diagnosis, 188 –191 emergent conditions that cause, 190 t evaluation and decision, 191 –193 pathophysiology, 188 from Pseudomonas infections, 188 sickle cell disease or trait and, 189 from Staphylococcus infections, 188 traumatic injuries and, 189 Visual loss associated with trauma, 193 mild, 193 not associated with trauma, 193 severe, 193 Vital signs, pediatric, 23 –24 , 23 t Vitamin B12 deficiency, 417 Vitamin K antagonists (VKAs), 1065 Vitamin K–deficient bleeding, 215 –216 VITAMINS mnemonic, 561 , 561 t Vitiligo, 465 Vocal cord dysfunction, 515 Vogt–Koyanagi–Harada syndrome, 189 Volvulus, malrotation of bowel, 1299 –1302 Vomiting, 119 , 148 t, 482 , 886 , 929 , 1304 appearance of vomitus, 548 association with diarrhea, 153 common causes, 550 t differential diagnosis, 551 f evaluation and decision general approach, 548 history, 548