Bottle-feeding was associated with an increased risk for HPS in a population-based case-control study of 714 infants. After adjustment for sex, race, maternal smoking status, and other factors, bottle-feeding was associated with an increased risk for HPS (odds ratio, 2.31; 95% confidence interval, 1.81 - 2.95) compared with breast feeding. This effect was most pronounced in the children of older and multiparous mothers.
Signs and symptoms
Features of the history in infants with HPS are as follows:
Typical presentation is onset of initially nonbloody, always nonbilious vomiting at 4-8 weeks of age
Although vomiting may initially be infrequent, over several days it becomes more predictable, occurring at nearly every feeding
Vomiting intensity also increases until pathognomonic projectile vomiting ensues
Slight hematemesis of either bright-red flecks or a coffee-ground appearance is sometimes observed
Patients are usually not ill-looking or febrile; the baby in the early stage of the disease remains hungry and sucks vigorously after episodes of vomiting
Prolonged delay in diagnosis can lead to dehydration, poor weight gain, malnutrition, metabolic alterations, and lethargy
Parents often report trying several different baby formulas because they (or their physicians) assume vomiting is due to intolerance
Careful physical examination provides a definitive diagnosis for most infants with HPS. The diagnosis is easily made if the presenting clinical features are typical, with projectile vomiting, visible peristalsis, and a palpable pyloric tumor. Early in the course of the disease, however, some of the classic signs may be absent.
Schedules that advance the volume of feeds more quickly or those that begin with ad lib feeds are associated with more frequent episodes of vomiting but do not increase morbidity and actually may decrease the time to hospital discharge
Addition of an H2 receptor blocker sometimes can be beneficial
Treat persistent vomiting expectantly because it usually resolves within 1-2 days
Avoid the temptation to repeat ultrasonography or upper GI barium study; these invariably demonstrate a deformed pylorus, and results are difficult to interpret