It is quite common for hyper- and hypofunction to occur simultaneously in several manifestations of diabetic neuropathy. Regarding sensory nerve function, hypoaesthesia is frequently preceded by hyperaesthesia . Hyperfiltration can be observed in the early phase of diabetic nephropathy, while decreased glomerular filtration rate is the usual finding in later phases. In diabetic enteropathy, such a sequence of disorders is not usual. However, consequences of gut hypo- and hyperfunction are often observed simultaneously . Constipation is the usual finding; however, paroxysmal nocturnal diarrhoea is also a characteristic finding of enteropathy. Obviously, other potential causes leading either to constipation or diarrhoea should be excluded. The lack of MMC phase 3 and antro-duodenal incoordination are considered to be autonomic manifestations . As a third leading symptom, faecal incontinence may occur. External anal sphincter weakness and anorectal incoordination are thought to be consequences of parasympathetic autonomic or central nervous dysfunction. A diagnostic approach for diabetic enteropathy is summarised in Fig. 1.
Several decades ago, gallbladder function was assessed by intravenous cholangiography, and the large, poorly contracting gallbladder with gallstones was the characteristic finding of autonomic involvement. Nowadays, cholangiography has been replaced by ultrasonography. We should be very careful when viewing ultrasound scans, as the large gallbladder with stones can be easily misinterpreted as a sign of acute inflammation.
The most common digestive complications of diabetes are impaired gastric motility, bowel dysfunctions and abdominal pain, and the therapeutic options for these complications are reviewed by Hans Törnblom in this issue .
In summary, the complexity of the neural regulation and the high number of reversible and irreversible pathogenetic factors modulating digestive and motility functions contribute to the diversity of the gastrointestinal manifestations in diabetic patients.