Diabetes Mellitus Tutorial

Question 1

A 28-year-old woman presents to the Accident and Emergency department with nausea and vomiting. She is due to get married in 3 months and has lost 1 stone in weight over the last 5 weeks, which she put down to getting a personal trainer. However, she has cancelled her recent gym classes due to tiredness. She has noticed blurred vision over the last few weeks. She looks unwell and is struggling to hold a conversation due to vomiting.

She is waking up three times a night and passing large volumes of urine and sleeps with a large bottle of water by her bedside. The blurred vision is intermittent, and she finds it difficult to focus on her laptop screen. There has been no change in bowel habit. She also reports being treated twice for a urine infection in the last 2 months.

what is your diagnosis? Why?

What immediate bedside tests would you wish to perform at this point?

Answer 1

Passing lots of urine could mean that she has a large amount of glucose in her urine, and water follows by osmosis - osmotic diuresis.

polydipsia and nocturia

UTI - increased glucose in urine makes it more likely

high blood sugar levels lead to osmosis of water out of the lense leading to change of shape.

type 1 diabetes - glut transporters cannot take glucose into cells so cannot utilise it - proteolysis and lipolysis occurs instead so there is muscle wastage and fat breakdown.

nausea and vomiting doesn’t really occur in type 2 diabetes. Type 1 diabetes is more acute. Ketone metabolic acidosis —> low pH in blood <7.3

Tests:

Fasting blood glucose

hbA1c

Urine dipstick test

Question 2

You receive these results in a patient with suspected type 1 diabetes: pH6.9 (7.35-7.45)

Glucose 28 mmol/L

Bicarbonate 5 mmol/L(22-29)

Capillary blood ketones 5.2 mmol/L (<1 mmol/L)

Work through these blood results and describe what is normal or abnormal about them and the likely diagnosis

Answer 2

Low pH uncompensated due to low bicarbonate, high glucose, high ketones

Question 3

What is responsible for ketone acidosis and why does this occur?

Answer 3

Insulin deficiency leads to an inability to utilise glucose and suppress proteolysis and lipolysis. Lipolysis produces ketone bodies which are acidic.

Question 4

why do people with type 2 diabetes get ketone acidosis less often?

Answer 4

they have enough insulin to suppress lipolysis

Question 5

what treatment does a patient with ketone acidosis need?

Answer 5

Insulin IV Infusion

FLUIDS IV

check blood tests to prevent hypokalaemia - potassium is likely to drop as insulin drives potassium into cells

Question 6

what treatment does a patient with type 1 diabetes need after first presentation?

Answer 6

Insulin subcutaneous injection kit - change site of injection to prevent lipohypertrophy - balls of fat

basal bolus regime

blood glucose monitoring kit

check feet and eyes (retina) annually

routine blood tests

kidney function tests - keep an eye out for diabetic nephropathy - microalbuminuria