<prompt> True statement regarding congenital hypertrophic pyloric stenosisSix month age presentBilous vomiting presentMetabolic alkalosisHypokalemic acidosis  <response>: i.e. Metabolic alkalosis: 78-79-Love Bailey 25th 174-75-CSDT 13thRepititive vomiting leads to hypocholeremic hypokalemic metabolic alkalosis. The urine is alkaline initially but eventually it becomes acidic paradoxical aciduriaINFANTILE HYPERTROPHIC PYLORIC STENOSIS Most commonly affects boys MF 4:1 aged 2-8 weeks it is rare after 3 months of age Characteristically the first born male child is affected Projectile non bilious vomiting Typically the baby feeds hungrily and vomits non-bilious milk curds towards the end of a feed. Blood may be seen in the vomitus in 5 of cases and coffee grounds or occult blood is frequently present With dehydration infants often have sunken fontanelles with dry mucous membranes and poor skin turgor, weight loss following progressive feeding intolerance Jaundice with indirect hyper bilirubinemia occurs in fewer than 10 of cases Gastric peristaltic waves can usually be seen moving from the left costal margin to the area of the pylorus In over 90 of cases the pyloric tumor or olive can be palpated when the infant is relaxed Erythromycin in early infancy has been linked to the subsequent development of hypertrophic pyloric stenosis Gastritis and reflux esophagitis occurs frequently, Aspiration of vomitus may produce pneumonia Abdominal ultrasound is the most sensitive and specific test when the muscle thickness is greater than 4 mm and length of the pylorus is greater than 16 mm Contrast upper gastrointestinal series is indicatedi If an experienced ultrasonographer is unavailableii If there is a reasonable chance that patients symptoms are not due to pyloric stenosis eg a premature, 1 week old baby Treatment - Fredet - Ramstedt pyloromyotomy 