pyloric stenosis

Pyloric stenosis is a condition of the very young infant that appears in the form of progressively severe vomiting starting in the first few weeks of life. It is caused by overdevelopment of the pyloric valve muscle like a bodybuilder's overgrown biceps and subsequent blockage of the outflow tract from the stomach to the small intestine. The muscle becomes too strong and squeezes the valve shut so forcefully that food is pushed forcefully in the reverse direction and right up and out of the stomach.

At first, pyloric stenosis may mimic gastroesophageal reflux, milk allergy, or normal baby spitting, but the vomiting becomes progressively more forceful. This is the true "projectile vomiting" everyone has heard about. The vomitus can literally shoot straight out for several feet, a phenomenon hard to believe until seen once.

Usually these infants are losing weight and look "worried" or distressed, as opposed to a refluxer who is often gaining very rapidly and happy as a clam. Sometimes a wave of contraction can even be seen rolling across the baby's abdomen just before a forceful vomiting episode.

Diagnosis is by history of progressive vomiting and physical exam; sometimes the pediatrician (and almost always the surgeon) can feel an "olive," namely the hard little knot of pyloric valve tissue on the right side of the baby's abdomen. An upper GI test (xray) or even better, an ultrasound will often be done before surgery to correct the problem. The surgery is fairly minor, and the baby will generally be eating normally and home with mom and dad in a day or two. The resultant scar is only an inch or so long and will be almost unnoticable in later life.

Ultrasound picture for the curious - 65K The outline shows the boundaries of the pyloric valve, which in this case is twice as thick and twice as long as it should be. There is a very narrow canal visible running horizontally from right to left between the outlines.

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