Type 1 Diabetes Mellitus (T1DM)
Type 1 diabetes mellitus is a chronic autoimmune condition where the body’s immune system destroys the insulin-producing beta cells in the pancreas. This results in an absolute deficiency of insulin, leading to high blood glucose levels. T1DM is the most common form of diabetes in children and requires lifelong insulin therapy.
Pathophysiology
The exact trigger for the autoimmune destruction of the beta cells is not fully understood, but it is believed to be a combination of genetic predisposition and environmental factors. The lack of insulin prevents glucose from entering the cells, leading to hyperglycaemia. The body then breaks down fat and muscle for energy, which produces ketones, a by-product of fat metabolism. The accumulation of ketones in the blood can lead to a dangerous condition called diabetic ketoacidosis (DKA).
Clinical Presentation
The classic presentation of T1DM is the triad of polyuria, polydipsia, and weight loss.
Polyuria: Frequent urination, as the kidneys try to excrete the excess glucose.
Polydipsia: Excessive thirst, in an attempt to rehydrate from the fluid loss.
Weight Loss: Despite eating, the child loses weight as the body breaks down fat and muscle for energy.
Other common symptoms include fatigue, blurred vision, and recurrent infections like thrush or nappy rash.
Diabetic Ketoacidosis (DKA)
DKA is a medical emergency that can be the presenting feature of T1DM. It’s characterised by:
Hyperglycaemia
Ketosis: The presence of ketones in the blood or urine.
Metabolic Acidosis: A low blood pH.
Children with DKA are usually unwell, with symptoms including abdominal pain, vomiting, a sweet or pear-drop smell on their breath (due to ketones), and deep, laboured breathing (Kussmaul respiration).
Diagnosis
The diagnosis is straightforward in a child with classic symptoms.
Blood Glucose: A random plasma glucose level of 11.1 mmol/L or more is diagnostic.
Urinalysis: A urine dipstick will show glucose and ketones.
Antibodies: The presence of pancreatic autoantibodies (e.g., islet cell antibodies, GAD antibodies, or insulin autoantibodies) supports the diagnosis.
Management
Management is complex and requires a multidisciplinary team.
Immediate Management (DKA):
Fluid Resuscitation: Administer intravenous fluids to correct dehydration.
Insulin Infusion: Start a continuous intravenous insulin infusion to lower blood glucose and stop ketone production.
Electrolyte Monitoring: Carefully monitor potassium and other electrolytes, as they can fluctuate significantly during treatment.
Ongoing Management:
Insulin Therapy: All children with T1DM require lifelong insulin therapy. This is usually given as a multiple daily injection regimen or via an insulin pump.
Blood Glucose Monitoring: Regular blood glucose monitoring is essential to guide insulin dosing. This is often done using a continuous glucose monitor (CGM).
Carbohydrate Counting: Children and families must learn to count carbohydrates in their food to match their insulin dose.
Education: Comprehensive education is provided to the child and family to help them manage the condition effectively.
Prognosis and Complications
With modern management, children with T1DM can lead a full and active life. However, they are at risk of both acute and chronic complications.
Acute Complications: Hypoglycaemia is a common complication and is managed with quick-acting carbohydrates.
Chronic Complications: Long-term complications include damage to the eyes (retinopathy), kidneys (nephropathy), and nerves (neuropathy).