Diabetes and the gastrointestinal tract

The range of gastrointestinal complications of diabetes extends from the mouth to the anus (see Figure 1). In some cases the resulting conditions are familiar – such as gastro-oesophageal reflux and constipation – and the relevance of the diabetes is little more than that these conditions are seen more frequently in diabetic patients than in the general population. Indeed, the treatments are the same in both groups and their effectiveness is comparable. But there are two unusual complications that are particular to diabetes: gastroparesis and diabetic diarrhoea. The management of patients with these problems can be extremely challenging; apart from the sheer unpleasantness of chronic vomiting and diarrhoea to the point of incontinence, fluid depletion and loss of diabetic control may necessitate hospital admission. Both vomiting and diarrhoea can be intractable, and the disappointing response of both conditions to the existing range of treatments is often frustrating for patient and physician. Much of the difficulty stems from the fact that their aetiology is poorly understood. The skills involved in looking after such patients extend far beyond the prescribing manual.