Type 3c diabetes after chronic pancreatitis: causes, symptoms and treatment

Most people know of type 1, type 2 and gestational diabetes, but there are less common forms. County Durham and Darlington NHS Foundation Trust describes type 3c diabetes, also known as pancreatogenic diabetes mellitus, as diabetes related to disorders of the pancreas. Mid Cheshire Hospitals NHS Foundation Trust describes it in similar terms: the pancreas is damaged and can no longer produce enough insulin, which can happen after conditions such as pancreatitis, pancreatic surgery or other pancreatic disorders.

The name is easy to confuse with “type 3 diabetes”, a term that has sometimes been used to describe a possible link between diabetes and Alzheimer’s disease. The trust stresses that this is different from type 3c diabetes, which is caused by pancreatic damage.

Pancreatic Cancer UK adds that in type 3c diabetes the pancreas may make less insulin and less glucagon than the body needs, and that the blood sugar level may become too high or too low. Insulin reduces the amount of glucose in the blood, and glucagon helps to increase it when needed.

The NHS describes chronic pancreatitis as a long-term condition in which the pancreas is inflamed, scarred and painful. It says damage and scarring to the pancreas can cause other problems, including difficulty absorbing nutrients from food and a type of diabetes called type 3c diabetes, which happens because the pancreas does not produce enough insulin.

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, which is the most common cause in children), the immune system attacking the pancreas, the pancreas not developing properly, and some medicines. Sometimes the cause is not clear.

Chronic pancreatitis is not the only cause. The County Durham and Darlington trust lists acute pancreatitis, chronic pancreatitis, pancreatic cancer, cystic fibrosis, haemochromatosis (a condition causing excess iron in the body) and surgical removal of the pancreas due to illness or injury as causes of the damage.

Because type 3c diabetes affects both blood sugar regulation and digestion, the trust lists a mix of symptoms. Chronic pancreatitis itself can cause some of the same ones: the NHS lists tummy pain, feeling or being sick, diarrhoea, very smelly poo that floats and is difficult to flush away, bloating, feeling thirsty or needing to pee a lot, and weight loss without trying.

• Unexplained weight loss.

• Stomach pain.

• Fatigue.

• Frequent wind or bloating.

• Diarrhoea.

• Fatty or oily stools (steatorrhoea).

• Low blood sugar (hypoglycaemia).

• Increased thirst and needing to pass urine more often, which are common diabetes symptoms.

The County Durham and Darlington trust advises speaking to your healthcare provider as soon as possible if you have these symptoms. For chronic pancreatitis, the NHS advises seeing a GP if you think you might have it, and asking for an urgent GP appointment or getting help from NHS 111 if you get sudden, severe tummy pain, which could be a sign of acute pancreatitis or another condition that may need hospital treatment as soon as possible.

Pancreatic Cancer UK lists sweating, confusion, feeling lightheaded and palpitations among the symptoms that can occur with type 3c diabetes. If you already have diabetes and your team has given you a plan for low blood sugar, follow it, and ask your team who to contact if your readings are not in your target range.

The County Durham and Darlington trust says many people with type 3c diabetes are initially diagnosed with type 2 diabetes because type 3c is less well known. It advises that if you have a history of pancreatic disease, your healthcare team should assess you for type 3c, and that you can ask your doctor to review your medical history and symptoms if you are unsure whether you have been assessed.

For the pancreatic condition itself, the NHS says there is no single test for chronic pancreatitis and a doctor may need to rule out other causes first. A GP may feel your tummy, check for yellowing of the skin or eyes, weigh you, arrange blood or stool tests and ask about relatives who have had pancreatitis. Specialists may arrange a CT or ultrasound scan or a gastroscopy.

The sources used here do not set out a specific diagnostic test for type 3c diabetes, so the way it is distinguished from type 2 depends on the clinical history and the judgement of the diabetes and pancreatic teams.

The trust says management can be challenging because it depends on the extent of pancreatic damage, and that the approach differs from type 1 or type 2 diabetes. It lists the usual components.

The NHS advises people with chronic pancreatitis to eat a healthy, balanced diet, to avoid alcohol because it can cause more damage to the pancreas even if alcohol was not the cause, and to stop smoking because this can help slow the damage. It says people will need regular check-ups, tests and scans for problems such as diabetes or weakened bones, and that the damage to the pancreas usually gets worse over time and is not possible to reverse, although most people live with it for many years.

A new diagnosis can be difficult. The trust notes that you may feel frustration or emotional distress and that it can help to talk to others. It points to NHS resources and organisations linked with conditions that cause type 3c, such as Pancreatic Cancer UK, Haemochromatosis UK and the Cystic Fibrosis Trust. Mid Cheshire’s page signposts Pancreatic Cancer UK guidance on healthy eating and on managing symptoms and side effects.

In the NHS, care is shared between the GP, a diabetes team (including a diabetes specialist nurse and dietitian) and, where a pancreatic condition is involved, a gastroenterology or pancreatic specialist. Pancreatic Cancer UK notes that who you see for diabetes may depend on services in your local area.

Some people also seek a private gastroenterology or endocrinology opinion, particularly if they feel their diabetes has been classified incorrectly. A useful question for any clinician is whether your pancreatic history has been taken into account.