T1DM

Question 1

Where is insulin produced?

Answer 1

Beta cells in the Islets of Langerhans in the pancreas

Question 2

What is the main function of insulin?

Answer 2

Reduces blood glucose by:

• Increasing cellular absorption of glucose
• Stimulates the liver and muscle cells to convert glucose to glycogen

Question 3

Where is glucagon produced?

Answer 3

Alpha cells in the Islets of Langerhans in the pancreas

Question 4

What is the function of glucagon?

Answer 4

Increases blood glucose (via glycogenolysis and gluconeogenesis)

Question 5

What is ketogenesis? Why does this occur?

Answer 5

Ketogenesis is the conversion of fatty acids into ketones as an alternative source of fuel. It occurs when there is insufficient glucose supply and glycogen stores are exhausted.

Question 6

In which circumstances does ketogenesis occur? Give examples.

Answer 6

• Fasting
• Low carb, high fat diets (“keto diet”)
• DKA

Question 7

The main problems of diabetic ketoacidosis are…

Answer 7

1. Ketoacidosis
2. Dehydration
3. Potassium imbalance

Question 8

Describe the pathophysiology of diabetic ketoacidosis

Answer 8

• Cells are unable to absorb glucose due to lack of insulin
• Therefore the body initiates ketogenesis (conversion of fatty acids to ketones as an alternative source of fuel)
• Over time, both the blood glucose and ketones levels get higher and higher
• Initially the kidneys produce bicarbonate to counteract the ketones in the blood to maintain normal pH
• Over time, the ketones use up the bicarbonate and the blood becomes acidic (metabolic ketoacidosis)

Question 9

Describe the pathophysiology of dehydration in DKA

Answer 9

• Hyperglycaemia results in glucose being filtered into the urine (glycosuria)
• The glucose in the urine draws water with it (osmotic diuresis) resulting in polyuria
• This results in severe dehydration (which in turn stimulates excessive thirst - polydipsia)

Question 10

Describe the pathophysiology of potassium imbalance in DKA

Answer 10

• Insulin normally drives potassium into cells. In the absence of insulin this does not occur (so total body potassium is low)
• Serum potassium may be high or normal as the kidneys attempt to maintain potassium homeostasis
• When treatment with insulin starts, patients can develop severe hypokalaemia very quickly

Question 11

What are the criteria for diagnosing DKA?

Answer 11

1. Hyperglycaemia (i.e. blood glucose > 11 mmol/L)
2. Ketosis (i.e. blood ketones > 3 mmol/L)
3. Acidosis (i.e. pH < 7.3)

Question 12

What are the symptoms of DKA?

Answer 12

• Polydipsia
• Polyuria
• N+V
• Altered consciousness

Question 13

Typically, people in ketosis have a characteristic smell to their breath. What smell is this?

Answer 13

Acetone

Question 14

How do you treat DKA?

Answer 14

Follow local protocol!!

Generally: FIG-PICK

• Fluids (IV fluid resus with normal saline, then follow protocol)
• Insulin infusion (fixed rate, e.g. Actrapid 0.1 units/kg/hour)
• Glucose - monitor and add a dextrose infusion if required (usually when BG <14)
• Potassium - monitor and correct as required
• Infection - investigate for potential triggers
• Chart fluid balance
• Ketones - monitor

Question 15

How do you alter a diabetic patient’s normal insulin regime when treating DKA?

Answer 15

• Continue their usual long-acting insulin

- Hold their short-acting insulin

Question 16

What is the maximum rate at which IV potassium can be infused?

Answer 16

Max rate = 10 mmol/hour

Question 17

Generally, how often should patients with T1DM monitor their capillary blood glucose?

Answer 17

• On waking
• At each meal
• Before bed

Question 18

Injecting insulin into the same spot can cause a condition called… What is this?

Answer 18

Lipodystrophy - this is where the subcutaneous fat hardens and patients will not absorb insulin properly from further injections into this spot

Question 19

What are the two main short term complications of poorly controlled T1DM?

Answer 19

• Hypoglycaemia

- Hyperglycaemia (and DKA)

Question 20

What are the typical symptoms of hypoglycaemia?

More severe hypoglycaemia can lead to…

Answer 20

• Tremor
• Sweating
• Irritability
• Dizziness
• Pallor

More severe hypoglycaemia can lead to reduced consciousness, coma and death

Question 21

What is the cut-off value for hypoglycaemia?

Answer 21

Blood glucose less than 4 mmol/L (four is the floor)

Question 22

Describe the management of hypoglycaemia in a patient who is…

1. Able to eat/drink
2. Unable to eat/drink, but has a cannula
3. Unable to eat/drink and does NOT have a cannula

Answer 22

1. Fast-acting glucose, e.g. dextrose tablets followed by slow-acting carbohydrates such as biscuits/toast
2. IV glucose, e.g. 100ml 20% glucose
3. IM glucagon

Question 23

What are the long term complications of poorly controlled T1DM? How can these complications be classified?

Answer 23

Microvascular:
- Diabetic neuropathy, nephropathy and retinopathy

Macrovascular:

• IDH and MI
• Stroke
• Hypertension

Infection-related complications:

• Bacterial, e.g. skin/soft tissue infections, UTIs
• Fungal, e.g. candidiasis

Question 24

How is T1DM monitored long term?

How often should this be done?

Answer 24

HbA1c

Every 3-6 months

Question 25

How does Flash Glucose Monitoring (FreeStyle Libre) work?

Answer 25

It uses a sensor on the skin to measure the glucose level of the interstitial fluid

Question 26

Is it still necessary to do a capillary blood glucose measurement in a patient with suspected hypoglycaemia, even if their FreeStyle Libre is showing a normal glucose level?

Answer 26

Yes - capillary blood glucose is still required as their is a 5 minute lag with the FreeStyle Libre