Jack is a 6 week old infant presenting with his mother with continued concerns for spitting up after feedings. He has been in the office

Jack is a 6 week old infant presenting with his mother with continued concerns for spitting up after feedings. He has been in the office every 3-4 days for the spitting up. Mom has changed his formula four times since his birth without any changes in the spitting up. You had prescribed a trial of simethicone 2 weeks ago and mom gave 1 dose without relief so stopped giving it. He formula intake has gone up to 4 ounces every 3 hours but he seems to vomit the entire amount and seems hungry after spitting up. Your believe he may have pyloric stenosis. You order a STAT abdominal ultrasound. Which of the following is another characteristic of pyloric stenosis that is a Red Flag to take into consideration when you are considering your differential diagnoses? Group of answer choices Failure to gain weight or weight loss over a short period of time Falling asleep after spitting up Only gaining 0.5-1 ounce a day Abdominal sunken in the epigastrium area