7.2 Diabetes Mellitis

Question 1

how does diabetes often cause premature death?

Answer 1

due to resulting cardiovascular diseases. Hyperglycaemia over years leads to damage of the small and large blood vessels causing cardiovascular diseases and premature death.

Question 2

what conditions are commonly associated with diabetes mellitus?

Answer 2

kidney disease (1 in 4 )
blindness
non traumatic lower limb amputation
cardiovascular diseases
shorter life expectancy
diabetic neuropathy and diabetic foot

Question 3

how does insulin affect cells?

Answer 3

insulin released by beta pancreatic cells travels in the blood and binds to extracellular membrane insulin receptor. Once bound insulin stimulates glucose to enter into cells from the blood stream via GLUT 4 channels

Question 4

why does blood glucose rise in diabetes mellitus?

Answer 4

type 1 = Inability to produce insulin due to beta cell failure
type 2 = Insulin production adequate but insulin resistance prevents insulin working effectively and invariably linked to obesity

Question 5

why is insulin not produced in type 1 diabetes mellitus?

Answer 5

autoimmune beta cell destruction. autoantibodies are produced against the beta cells.

Question 6

what factors affect the development of type 1 diabetes?

Answer 6

mostly genetic predisposition alongside environmental trigger

Question 7

what is meant by relative insulin deficiency?

Answer 7

Pancreas is producing enough insulin but cells/receptors have loss affinity for insulin and less glucose enters cells.

Question 8

what are typical symptoms of hyperglycaemia?

Answer 8

polyuria, polydipsia, blurring of vision, urogenital infection(thrush)

Question 9

what are symptoms of inadequate energy utilisation?

Answer 9

tiredness, weakness, lethargy, weight loss.

Question 10

what are the presenting symptoms of diabetes mellitus?

Answer 10

• hyperglycaemia and associated symptoms

- inadequate energy utilisation

Question 11

what will the severity of diabetes symptoms depend on?

Answer 11

1. absolute levels of glucose achieved

2. rate of rise of blood glucose

Question 12

How is diabetes diagnosed?

Answer 12

1. Fasting glucose
2. Oral Glucose tolerance test
3. HbA1c
4. You need symptoms and 1 abnormal test or 2 if
   asymptomatic (symptoms include hyperglycaemia and inadequate energy utilisation)

Question 13

what are the presenting symptoms for type 1 diabetes?

Answer 13

Rapid onset (usually weeks), weight loss, polyuria and polydipsia
Late presentation there may be vomiting due to ketoacidosis

Question 14

what are the presenting signs of a patient with undiagnosed type 1 diabetes?

Answer 14

Usually, but not always, young < 30 years
Elevated venous plasma glucose
Presence of ketones (breakdown products of fats)

Question 15

what is the treatment for type 1 diabetes?

Answer 15

exogenous insulin given by a subcutaneous injection several times a day. cannot be given orally as insulin breaks down rapidly in the stomach

Question 16

why are ketones used as an indicator of diabetes?

Answer 16

ketones are produced from the breakdown of fats, and as insulin is anti-lipolysis ketone production is suppressed by insulin. Ketones are only detected in healthy people during starvation in serum or urine. in the absence of insulin ketone production is activated. Presence of ketones in a patient with healthy diet is an indication for immediate insulin therapy.

Question 17

What is ketoacidosis?

Answer 17

Ketones accumulate in blood stream. Presents as hyperglycaemia, ketonaemia and acidosis

Question 18

how does diabetes lead to ketoacidosis?

Answer 18

1. Absolute or relative deficiency of insulin
2. Enhanced lipolysis leads to uncontrolled ketosis
3. Large quantities of ketone bodies formed including 3-
   beta-hydroxybutyrate, acetoacetic acid and acetone

Question 19

what are the 3 ketone bodies produced in the body?

Answer 19

beta-hydroxybutyric acid (a.k.a. 3-hydroxybutyric acid)
acetoacetic acid
acetone

Question 20

whom is most at risk of developing type 2 diabetes?

Answer 20

overweight or obese patients

people over the age of 40 however is increasingly seen in younger people and children

Question 21

what causes insulin resistance to develop in type 2 diabetes?

Answer 21

obesity
muscle and liver fat deposition 
elevated circulating free fatty acids
physical inactivity
genetic influences

Question 22

why can low calorie dieting be seen as a treatment for type 2 diabetes?

Answer 22

as low calorie dieting decreases intraabdominal, intrapancreatic and intrahepatic fat levels. Results in the return of normal insulin sensitivity and normalises beta cell function

Question 23

what are the symptoms of type 2 diabetes?

Answer 23

Very variable as slower rise in blood glucose
May have polyuria, polydipsia, weight loss. Can be difficult to elicit from patient. No urinary ketones. May be asymptomatic.

Question 24

how are most patients diagnosed with type 2 diabetes?

Answer 24

Diagnosis made by routine screen

Question 25

how do we treat type 2 diabetes?

Answer 25

1. lifestyle - low calorie dieting, weight loss
2. non-insulin therapies (Biguanides, sulphonylureas,
   thiazolidinediones, GLP1 analogues. DPP4
   inhibitors, alpha-Glucosidase inhibitors, SGLT2s)
3. insulin
4. Require patient education and ability to monitor results of therapy
5. Look for other vascular risk factors – BP, lipids, smoking, exercise, diet
6. Surveillance for chronic complications

Question 26

what are common acute complications of diabetes?

Answer 26

hyperglycaemia
Massive metabolic decompensation
Diabetic ketoacidosis in type 1
Hyperosmolar non-ketotic syndrome in type 2
Acute complications of hypoglycaemia (Coma as brain needs glucose)
Caused by hypoglycaemic therapy (too much insulin)

Question 27

what are common chronic complications of diabetes?

Answer 27

Macrovascular or large vessel disease
• Cerebrovascular, cardiovascular, peripheral vascular disease
• Stroke, heart attack, intermittent claudication,
gangrene

Microvascular or capillary disease
• Retinopathy, nephropathy, neuropathy
• Blindness, need for renal replacement therapy, erectile dysfunction, foot ulceration, diarrhoea, constipation, painful peripheral neuropathy

Question 28

what is metabolic syndrome?

Answer 28

Metabolic syndrome is a cluster of the most dangerous risk factors associated with cardiovascular disease: diabetes and raised fasting plasma glucose, abdominal obesity, high cholesterol and BP. Together they mark an increase in cardiovascular risk

Question 29

how do you measure if a patient has metabolic syndrome?

Answer 29

Waist measurement > 94cm for men and > 80 cm for women
Plus any 2 of the following:
• Raised triglyceride > 1.7mmol/l or treatment
• Reduced HDL cholesterol <1.0 for men and 1.2mmol/l for women
• Raised blood pressure > 135/85 or treatment
• Or raised fasting blood glucose > 5.6mmol/l or treated diabetes

Question 30

what causes metabolic syndrome?

Answer 30

Insulin resistance and central obesity, genetics, physical inactivity, ageing

Question 31

what is intermittent claudication?

Answer 31

Intermittent claudication is pain affecting the calf, and less commonly the thigh and buttock, that is induced by exercise and relieved by rest. Symptom severity varies from mild to severe. Intermittent claudication occurs as a result of muscle ischaemia during exercise caused by obstruction to arterial flow.

Question 32

What is insulitis?

Answer 32

inflammation of the islets. Chronic inflammatory mononuclear cell infiltrate consisting of T-lymphocytes and macrophages is found associated with the islets of newly diagnosed type-1 diabetics.

Question 33

how might a patient with untreated type-1 diabetes present to A&E?

Answer 33

Younger (below 30yrs)
ketoacidosis = ketonuria, smell of acetone on the breath, hyperventilation, nausea, vomiting, abdominal pain
hyperglycaemia = glucosuria, polydipsia, polyuria, confusion due to dehydration

Question 34

what is the HbA1c test?

Answer 34

HbA1c is a glycated form of haemoglobin measured to identify the average plasma glucose concentration over prolonged periods. Provides an accurate diagnosis of glycaemic control.