Type 3c diabetes: what it is, symptoms, diet and treatment

Diabetes UK describes type 3c as diabetes that develops because of damage to the pancreas, which can happen for a few different reasons. The pancreas makes insulin, which lets glucose in the blood enter the body's cells to fuel them, and it also makes the enzymes that digest food. When it is damaged, it may stop producing enough of either.

The NHS explains that diabetes is caused by the body not making enough insulin or the insulin not working properly (insulin resistance), and that type 1 is usually caused by a problem with the immune system. Type 3c is different from both because its starting point is damage to the pancreas itself.

It has the usual diabetes symptoms. The NHS lists feeling thirsty all the time, peeing more than usual, feeling very tired and losing weight without trying. Because the pancreas may also be unable to supply digestive enzymes, Diabetes UK lists extra signs to look out for:

• losing weight without trying to

• stomach pain

• feeling more tired than usual

• frequently passing wind

• diarrhoea and fatty or oily stools

• hypoglycaemia, also called low blood sugar

Diabetes UK says your healthcare team will usually discuss diet and lifestyle changes, treatment to help with digesting food, and may refer you to a dietitian.

Guts UK, writing about chronic pancreatitis (a common cause), says most people should eat a normal balanced diet, although some find it easier to have more smaller meals through the day, and that dietary restrictions can be harmful. It says a low-fat diet can mask the symptoms of pancreatic exocrine insufficiency and is not an appropriate treatment for most people; the correct approach is prescribed digestive enzymes so that a normal diet can be eaten.

Guts UK also advises that everyone with chronic pancreatitis should see a specialist qualified dietitian, and says the enzymes sold by health food shops contain tiny amounts and are not likely to be effective. The only effective enzymes are those prescribed by a doctor or non-medical prescriber such as a specialist nurse.

Diabetes UK says current guidelines advise treating type 3c with metformin or insulin, and that there is no one-size-fits-all approach because it depends on how much damage the pancreas has. People are likely to start on metformin, and if that is not enough and weight is being lost, they move on to insulin. If metformin is working, it suggests a check every six months to see whether insulin is needed.

Guts UK says type 3c can be difficult to control and that people are usually referred to a specialist diabetes service when that happens. It also says insulin can help people put weight and muscle back on.

If the pancreas is not making enough digestive enzymes, treatment is pancreatic enzyme replacement therapy (PERT). Guts UK says the capsules are taken spread throughout every meal and with snacks containing fat, and that an acid-reducing medicine may also help. The NHS lists, for chronic pancreatitis, painkillers, medicines that help the body absorb nutrients from food, and medicines for diabetes such as insulin. It also advises not drinking alcohol and not smoking.

Diabetes UK says type 3c can only occur because of an illness or condition that affects the pancreas. It lists acute pancreatitis, chronic pancreatitis, pancreatic cancer, cystic fibrosis and haemochromatosis, and says it can also develop if your pancreas is removed because of any other damage.

The NHS lists type 3c diabetes among the problems that chronic pancreatitis can cause. Guts UK says that between 25 and 80 people in 100 with chronic pancreatitis will develop diabetes within 10 to 20 years, and that people with chronic pancreatitis should be monitored for diabetes every six months, even without symptoms, with a simple blood test called HbA1c.

The NHS says the most common cause of chronic pancreatitis is drinking alcohol, and that it can also be linked to smoking, genes (including the gene that causes cystic fibrosis, the most common cause in children), the immune system attacking the pancreas, and some medicines.

Diabetes UK says there is a lack of awareness of type 3c, which might mean an incorrect diagnosis, and that you can ask your doctor to check for type 3c if you have had pancreatic problems and explain why. The NHS says type 2 diabetes is diagnosed with a blood test that checks how high blood glucose levels are.

Guts UK says many people with chronic pancreatitis develop secondary or type 3c diabetes and are wrongly diagnosed with type 2, which leads to inadequate treatment. It says people with chronic pancreatitis should have a yearly faecal elastase test to monitor for pancreatic exocrine insufficiency, a stool test that checks how well the pancreas is producing digestive enzymes.

Guts UK says people with chronic pancreatitis are at risk of weakened bones and vitamin D deficiency, and recommends a bone density (DEXA) scan every two years. It also says the NICE guideline for pancreatitis recommends that people with chronic pancreatitis are offered monitoring of their pancreatic exocrine function and nutritional status at least every 12 months.

The NHS says a long-term condition like diabetes can increase the chance of other problems, including heart attack and stroke, kidney problems, nerve damage and foot problems, and sight problems. Your diabetes team will arrange regular checks for these.

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. It also says to ask for an urgent GP appointment or get help from NHS 111 if you or your child has any symptoms of diabetes.

Low blood sugar (hypos) needs prompt treatment. The NHS says it is usually where blood sugar is below 4mmol/L, and describes treating it with something that raises blood sugar quickly, such as a small glass of fruit juice. Call 999 if someone with very low blood sugar is unconscious or not responding normally and a glucagon injection is not available or does not work.

Diabetes UK says that if you have a type 3c diagnosis you should be seen by a healthcare team that knows what to do. Guts UK says care involves a multidisciplinary team: your GP, pancreas specialists in the hospital, specialist nurses and dietitians, with referral to specialist diabetes services if control is difficult.

Some people seek a private gastroenterology or endocrinology opinion for a second view or quicker tests. Whichever route you use, make sure the team knows about your pancreatic history and that your GP receives the plan.