Type 1 Diabetes

What is type 1 diabetes?

Type 1 diabetes is an autoimmune condition in which the immune system destroys the insulin producing beta cells of the pancreas, so insulin is required for life. It is not caused by diet or lifestyle and most often presents in childhood or young adulthood. Untreated it progresses to diabetic ketoacidosis, which is a medical emergency.

Causes

• Autoimmune destruction of pancreatic beta cells
• Genetic susceptibility including HLA associations
• Possible viral triggers
• Islet autoantibody development preceding symptoms

Symptoms

• Excessive thirst
• Frequent urination including at night
• Unintended and often rapid weight loss
• Extreme fatigue
• Blurred vision
• Recurrent thrush
• Fruity smelling breath in ketoacidosis
• Nausea, vomiting and abdominal pain in ketoacidosis

Risk factors

• Family history of type 1 diabetes
• Specific HLA genetic variants
• Other autoimmune conditions such as coeliac or thyroid disease
• Northern European ancestry
• Peak onset in childhood and adolescence

Diagnosis

• Raised blood glucose with classic osmotic symptoms
• Ketone testing in blood or urine
• Islet autoantibodies including GAD and IA2
• Low C peptide indicating minimal insulin production
• Urgent same day referral when suspected in a child

Treatment

• Lifelong insulin by injection or pump
• Carbohydrate counting and dose adjustment education
• Continuous glucose monitoring
• Hybrid closed loop systems where available
• Hypoglycaemia recognition and treatment training
• Annual screening for eye, kidney, foot and coeliac complications
• Sick day rules to prevent ketoacidosis

Self care

• Take insulin as prescribed and never omit doses when unwell
• Check glucose regularly, or use continuous glucose monitoring
• Learn carbohydrate counting and how to adjust doses
• Carry fast acting glucose for hypoglycaemia at all times
• Follow sick day rules, including checking ketones during illness
• Inspect feet regularly and attend annual screening appointments
• Wear or carry medical identification

When to see a doctor

Book an appointment if:

• Frequent or unpredictable low glucose episodes
• Loss of the usual warning symptoms of hypoglycaemia
• Glucose consistently outside your target range
• Planning pregnancy, which needs preconception review
• New foot ulcers, numbness or changes in vision
• Difficulty coping with the demands of daily management

Some symptoms need emergency care rather than an appointment. See the warning signs listed above.

Prevention

• Type 1 diabetes cannot currently be prevented, since it is autoimmune
• Complications can be prevented through steady glucose control
• Attend annual eye, kidney and foot screening
• Keep blood pressure and cholesterol in target range
• Do not smoke
• Follow sick day rules to prevent ketoacidosis

Outlook

With modern insulin regimens, continuous glucose monitoring and closed loop technology, most people with type 1 diabetes live full lives with a near normal life expectancy. Long term outlook depends largely on sustained glucose control and on screening that catches eye, kidney and nerve complications early, when they are still treatable.

Related conditions

Common questions