What is Dumping?

 The name Dumping has been given to a collection of symptoms that occur after a meal in patients who have undergone certain operations upon the stomach.

The symptoms fall into two groups.  One group consists of symptoms that appear to be definitely related to the digestive tract:  the patient feels sick, their abdomen feels bloated, they experience borborygmi, (a word that means tummy-rumblings), and this combination of symptoms sometimes leads up to passing a bulky, loose bowel motion. The other group of symptoms is quite different. Patients feel tired and want to lie down, and this may progress until they actually feel faint and sweaty and are aware that their heart is thumping (palpitations).

What is the Cause?

The cause of the symptoms is that the stomach is emptying its mixture of food and gastric juice into the intestines at a rate that is greater than normal.

Normally, when food enters the stomach it mixes with the gastric juice and digestion commences.  The valve at the lower end of the stomach, the pylorus, acts as a brake on stomach emptying, so that the mixture is allowed through only bit by bit.  If the valve is removed by surgery, or its function reduced by paralysing the muscle that forms the valve, the mixture gushes through into the intestine and causes the symptoms.

How are the Symptoms Produced?

The same mechanism is involved in the production of both sets of symptoms:  it is called ‘osmotic pressure’.  The partly-digested food mixture contains a larger number of molecules than the food that was eaten because much of the starch in the diet has been broken down to sugars.  A strong solution of sugar in the intestine makes the bowel contract vigorously (producing the tummy-rumbling) so that it is rapidly spread throughout the length (20 feet or so!) of the small bowel.  A strong solution of sugar then acts like blotting paper to suck water out of the much less concentrated tissue fluids of the body.  It is this sucking effect, which one can think of as an attempt by nature to equalise the concentrations of sugar in the gut and the blood, that is called osmotic pressure.

This rapid shift of fluid from the body into the gut has been measured, and can be as large as 1.5 litres (three pints).  Part of it comes from the blood itself (the rest from other parts of the body), and the fall in blood volume leads to faintness, sweating, desire to lie down and palpitations.  The extra three pints of water in the guts leads to the feeling of bloating, makes the tummy rumbling worse, and if bad enough can end up with the passage of the excess liquid as the watery diarrhoea.