5. Diabetes Mellitus Type 1

Question 1

At what range of concentrations does the body try to keep blood glucose at?

Answer 1

4.4 - 6.1 mmol/l

Question 2

What is the role of insulin and where it is produced?

Answer 2

It is produced by the beta cells in the Islets of Langerhans in the pancreas.

It is an anabolic hormone that reduces blood sugar

Question 3

How does insulin reduce blood sugar

Answer 3

2 WAYS

1) It causes/allows cells in the body to absorb glucose from the blood and use it as fuel
2) It causes muscle and liver cells to absorb glucose from the blood and store it as glycogen

Question 4

When does insulin levels rise?

Answer 4

When we eat

Question 5

What is the role of glucagon and where is it produced?

Answer 5

It is produced by the alpha cells of the islets of Langerhans in the pancreas.

It is a catabolic hormone that results in stored glycogen in the liver to be broken down into glucose and released into the blood

Question 6

What 2 processes does glycogen do?

Answer 6

Glycogenolysis - Tells the liver to break down stored glycogen into glucose.

Gluconeogenesis - Tells the liver to convert proteins and fats into glucose.

Question 7

What is type 1 diabetes mellitus?

Answer 7

It is a disease where the pancreas stops being able to produce insulin. When there is no insulin being produced, the cells of the body cannot take glucose from the blood and use it for fuel. Therefore the cells think the body is being fasted and has no glucose supply. Meanwhile the level of glucose in the blood keeps rising, causing hyperglycemia.

Question 8

What are the causes of type 1 diabetes mellitus?

Answer 8

It is unclear. There may be a genetic component. It may be triggered by certain viruses, such as the Coxsackie B virus and enterovirus.

Question 9

What physiological process occurs when the cells have no glucose available, and all glycogen stores are exhausted.

Answer 9

The body performs ketogenesis

Question 10

What is ketogenesis?

Answer 10

Occurs when there is no glucose or glycogen available. The liver takes fatty acids and converts them to ketones which are water soluble and used as an energy source. They can also cross the blood-brain barrier so are also used by the brain as fuel as well.

Question 11

When do you expect to see someone in ketosis?

Answer 11

• When fasting
• When on a low carb / high fat diet (keto diet)
• When in diabetic ketoacidosis

Question 12

How do you measure ketone levels in someone?

Answer 12

• Urine dip-stick
• Check ketone levels in the blood

Also, those in ketosis have a characteristic acetone smell to their breath.

Question 13

Does the blood pH get buffered in ketoacidosis?

Answer 13

In normal healthy patients, yes.

However, when an underlying pathology (ie. type 1 diabetes) causes extreme hyperglycaemic ketosis, then it results in metabolic acidosis

Question 14

What is diabetic ketoacidosis?

Answer 14

This is where there is both hyperglycaemia and ketosis.

Question 15

What are the main problems with diabetic ketoacidosis?

Answer 15

• Ketoacidosis (initially the kidneys produce bicarbonate to counteract the ketone acids, but eventually they all get used up, meaning the blood starts to become acidic)
• Dehydration
• Potassium imbalance

Question 16

Why do you have dehydration in type 1 diabetes?

Answer 16

Hyperglycaemia overwhelms the kidneys and glucose starts being filtered into the urine. The glucose in the urine draws water out with it in a process called osmotic diuresis. This causes the patient to urinate a lot (polyuria). This results in severe dehydration.

Question 17

Why are type 1 diabetic patients constantly thirsty? What is this called?

Answer 17

The dehydration stimulates the thirst centre to tell the patient to drink lots of water. This excessive thirst is called polydipsia.

Question 18

Why do you have a potassium imbalance in type 1 diabetes?

Answer 18

Insulin is responsible for driving potassium into the cells, so without it, there is no potassium stored in the cells.

Question 19

Why do type 1 diabetics have high serum potassium but low total body potassium?

Answer 19

Insulin normally drives potassium into the cells. Serum potassium can be high or normal as the kidneys continue to balance blood potassium with the potassium excreted in the urine, however total body potassium is low because no potassium is stored in the cells.

Question 20

What do you have to be aware of when starting a type 1 diabetic on insulin?

Answer 20

They may develop hypokalemia as the potassium is taken up by the cells, and this can very quickly lead to fatal arrhythmias

Question 21

Someone with diabetic ketoacidosis will present with what signs?

Answer 21

• Hyperglycaemia
• Dehydration
• Ketosis
• Metabolic acidosis (with a low bicarbonate)
• Potassium imbalance

Question 22

What symptoms will someone in diabetic ketoacidosis have?

Answer 22

• Polyuria
• Polydipsia
• Nausea and vomiting
• Acetone smell to their breath
• Dehydration and subsequent hypotension
• Altered Consciousness
• They may have symptoms of an underlying trigger (i.e. sepsis)

Question 23

What do you require in order to diagnose diabetic ketoacidosis?

Answer 23

• Hyperglycaemia (i.e. blood glucose > 11 mmol/l)
• Ketosis (i.e. blood ketones > 3 mmol/l)
• Acidosis (i.e. pH < 7.3)

Question 24

What is DKA?

Answer 24

Diabetic Ketoacidosis

Question 25

How do you treat DKA?

Hint: theres a mnemonic

Answer 25

Mnemonic : FIG-PICK

F – Fluids – IV fluid resuscitation with normal saline (e.g. 1 litre stat, then 4 litres with added potassium over the next 12 hours)

I – Insulin – Add an insulin infusion (e.g. Actrapid at 0.1 Unit/kg/hour)

G – Glucose – Closely monitor blood glucose and add a dextrose infusion if below a certain level (e.g. 14 mmol/l)

P – Potassium – Closely monitor serum potassium (e.g. 4 hourly) and correct as required

I – Infection – Treat underlying triggers such as infection

C – Chart fluid balance

K – Ketones – Monitor blood ketones (or bicarbonate if ketone monitoring is unavailable)

Question 26

What should you do with someone suffering from DKA prior to stopping their insulin and fluid infusion?

Answer 26

Establish the patient on their normal subcutaneous insulin regime prior to stopping the insulin and fluid infusion.

Question 27

What is the maximum rate of infusion for potassium?

Answer 27

It should not be infused at a rate of more than 10 mmol per hour.

Question 28

What does the long-term management of type 1 diabetes involve?

Answer 28

• Subcutaneous insulin regimes
• Monitoring dietary carbohydrate intake
• Monitoring blood sugar levels on waking, at each meal and before bed
• Monitoring for and managing complications, both short and long term

Question 29

What condition can occur as a result of continued insulin injections in the same spot? How do you prevent it?

Answer 29

Lipodystrophy (this is where the subcutaneous fat hardens and patients do not absorb insulin properly from further injections in this spot).

For this reason, patients should cycle their injection sites.

Question 30

What are short-term complications of type 1 diabetes mellitus?

Answer 30

• Hypoglycaemia

- Hyperglycaemia (and DKA)

Question 31

Why might type 1 diabetics have hypotension?

Answer 31

They may have injected too much insulin

Question 32

How is hypoglycaemia treated in someone with type 1 diabetes?

Answer 32

Hypoglycaemia needs to be treated with a combination of rapid acting glucose such as lucozade and slower acting carbohydrates such as biscuits and toast for when the rapid acting glucose is used up. Options for treating severe hypoglycaemia are IV dextrose and intramuscular glucagon.

Question 33

What is the effect of chronic hyperglycaemia?

Answer 33

Chronic exposure to hyperglycemia causes damage to the endothelial cells of blood vessels. This leads to leaky, malfunctioning vessels that are unable to regenerate. High levels of sugar in the blood also causes suppression of the immune system, and provides an optimal environment for infectious organisms to thrive.

In summary, there are

• Macrovascular complications
• Microvascular complications
• Infection related complications

Question 34

What are some of the macro vascular complications of type 1 diabetes?

Answer 34

• Coronary artery disease is a major cause of death in diabetics
• Peripheral ischaemia causes poor healing, ulcers and “diabetic foot”
• Stroke
• Hypertension

Question 35

What are some of the micro vascular complications of type 1 diabetes?

Answer 35

• Peripheral neuropathy
• Retinopathy
• Kidney disease, particularly glomerulosclerosis

Question 36

What are some of the infection related complications of type 1 diabetes?

Answer 36

• Urinary Tract Infections
• Pneumonia
• Skin and soft tissue infections, particularly in the feet
• Fungal infections, particularly oral and vaginal candidiasis

Question 37

What 3 techniques do we have to monitor blood glucose levels in diabetes?

Answer 37

• HbA1c
• Capillary blood glucose
• Flash Glucose Monitoring (e.g. FreeStyle Libre)

Question 38

What is HbA1C? Why is it used in those with diabetes?

Answer 38

It shows how much glucose is attached to the haemoglobin. This is considered to reflect the average glucose level over the last 3 months because red blood cells have a lifespan of around 3-4 months. We measure it every 3 – 6 months to track progression of the patient’s diabetes and how effective the interventions are. It requires a blood sample sent to the lab.

Question 39

What is capillary blood glucose tests? Who is it sued by, and when is it used?

Answer 39

This is measured using a little machine called a glucose meter that gives an immediate result. Patients with type 1 and type 2 diabetes rely on these machines for self-monitoring their sugar levels.

Question 40

What is flash glucose monitoring?

Answer 40

There is a sensor on the skin that measures glucose level of interstitial fluid. It records this at short intervals over time so shows glucose levels over time. There is a 5 minute lag time behind the results. The sensors need to be replaced every 2 weeks. It is quite expensive at the moment and there isn’t that much NHS funding for it.