The gastrointestinal and nervous systems are intimately connected. In this article, we focus on the neurological complications of gastrointestinal, hepatic and pancreatic disease in adult patients.

THE PANCREAS

Pancreatic function is essential for the maintenance of digestive functioning and hormonal balance. The neurological consequences of diabetes are well known and will be discussed in another review in this series. Hypoglycaemia due to insulinoma may present with a changed conscious level, epilepsy, stroke-like episodes, dementia or psychosis, or neuropathy. Shaw and colleagues¹ described a 27-year-old woman with dystonic choreoathetosis. Symptoms and signs may be focal, mimicking structural lesions.

Acute pancreatitis can lead to an encephalopathy, characterised by focal signs, cognitive impairment, seizures and hallucinations.² Cerebral imaging is usually normal. Sudden blindness has also been reported secondary to a retinopathy (Purtscher’s syndrome)³ or optic neuritis.⁴ Acute pancreatitis may also lead to renal failure and an associated thrombotic microangiopathy characterised by confusion and seizures, and responsiveness to plasma exchange.⁵ Gross and coworkers⁶ reported four patients with pancreatitis complicated by severe axonal neuropathy. All these patients, however, required intensive care treatment and had been treated with metronidazole. Vallat and Vital⁷ reported on a single patient with encephalopathy and axonal neuropathy complicating a severe pancreatitis.

THE GUT

Malabsorption

Malabsorption may occur as a consequence of primary gastrointestinal pathology (eg, coeliac disease) or iatrogenically after extensive resection of the small bowel. Table 1 summarises the neurological consequences of various vitamin deficiencies.

Vitamin B₁₂ deficiency may arise due to poor intake (vegans), malabsorption (fish tapeworm, ileal resection, bacterial overgrowth, tropical sprue and post-gastrectomy states), immune-mediated disease (pernicious anaemia) or rarely as a consequence of genetic disorders that affect transporter proteins.^8,9 The neurological complications include a sensory neuropathy, myelopathy, optic …