Pancreatic insufficiency (PEI): symptoms, causes, tests and enzyme treatment

The pancreas has two main jobs. It makes digestive enzymes that break food down into parts small enough to be absorbed, and it makes hormones such as insulin. Guts UK describes the enzyme job as the exocrine function, and PEI is when it fails. The key enzymes are lipase (for fat), proteases (for protein) and amylase (for starchy carbohydrate).

A healthy pancreas has a large reserve, so Guts UK says PEI develops slowly, over time or after prolonged or severe damage, or when the pancreatic duct is blocked. When too few enzymes reach the small bowel, nutrients pass through undigested and are not absorbed, which is called malabsorption.

Guts UK says the symptoms may be mild at first. The best known is steatorrhoea, fatty poo, which can look bulky, oily, pale orange or yellow, be foul-smelling and runny, and can float and be hard to flush away.

• Belly discomfort or pain.

• Bloating and wind.

• Fatty stools and diarrhoea.

• Weight loss and muscle wasting.

• Signs of low fat-soluble vitamins (Guts UK names A, D and K), which it says can include bone problems, bruising, poor wound healing, increased infections, poor night vision, nerve symptoms, muscle weakness and fatigue.

The NHS page on chronic pancreatitis, a leading cause of PEI, lists symptoms such as tummy pain, feeling sick, diarrhoea, very smelly poo that floats and is difficult to flush away, bloating, and losing weight without trying, and advises seeing a GP if you think you might have it.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you get sudden, severe pain in your tummy, which could be a sign of acute pancreatitis or another condition that may need hospital treatment as soon as possible.

Guts UK notes that some painkillers that cause constipation, such as codeine and other morphine-based medicines, can mask the diarrhoea of PEI, so weight loss and belly discomfort can still occur.

Guts UK explains that any disease that affects pancreatic tissue can cause PEI. As well as the common causes above, it lists surgery on the pancreas and sometimes upper digestive tract surgery, including total gastrectomy and, in up to 2 in 10 people, bariatric surgery. PEI can also occur in people with diabetes, and rarer inherited causes exist.

It adds that PEI becomes more common with age. The NHS says chronic pancreatitis is most commonly caused by drinking alcohol, and that it can also be linked to smoking, genes (including the cystic fibrosis gene), and the immune system attacking the pancreas.

Guts UK describes diagnosis as a skilled clinical task. It starts with symptoms and examination for weight loss or malnutrition, followed by tests of the structure of the pancreas (ultrasound, CT or MRI, sometimes endoscopic ultrasound) and of how well it works.

The test used most in the UK is the faecal elastase-1 test, which measures an enzyme in a poo sample. It is convenient because it needs no blood test or invasive examination, but Guts UK warns that it can miss mild to moderate PEI and can give false positives in other causes of diarrhoea. Where tests and symptoms disagree, further tests may be needed, including looking for other digestive conditions.

Guts UK says PERT is the standard treatment. Capsules containing lipase, amylase and proteases are taken with meals, snacks and milky drinks, so that the enzymes mix with food in the top of the small bowel. When taken properly, PERT can improve absorption, reduce fatty stools, wind and belly pain, increase body weight and improve nutritional status and quality of life.

The dose should be adjusted to the size and fat content of the meal, and capsules taken on an empty stomach will not work. Guts UK says there are four brands available (Creon, Pancrease, Nutrizym and Pancrex), that the enzymes come from pork, and that no vegetarian or vegan alternative currently exists. It adds that over-the-counter digestive enzyme products contain tiny amounts and are unlikely to be effective.

A proton pump inhibitor may be prescribed with PERT because acid can stop the enzymes working, Guts UK explains. Low-fat diets should not be used to manage PEI, it says, because they only hide the symptoms, and some people also need vitamin and mineral supplements arranged with a dietitian.

Guts UK says that NICE recommends people with chronic pancreatitis be offered monitoring of their pancreatic exocrine function and nutritional status at least every 12 months, plus HbA1c checks at least every six months and a bone density assessment every two years. This is agreed with a specialist pancreatic centre.

Guts UK also says people with PEI can develop diabetes, and that someone whose symptoms continue despite PERT should have the dose reviewed and, if needed, be checked for conditions such as bile acid diarrhoea, small bowel bacterial overgrowth and coeliac disease. The charity advises asking for a review of the enzyme medicine rather than altering the diet to manage symptoms.