Diabetes Mellitus
Prof Seamus Sreenan
Dept of Diabetes and Endocrinology,
Connolly Hospital, Blanchardstown
Mini Med School
November 30th, 2011
Learning Objectives

At the end of this talk you should
understand:
–
–
–
–
What diabetes mellitus means
The difference between types-1 and -2 diabetes
How the different types are treated
The reasons for the current epidemic of
diabetes and how it can be prevented
– What the complications of diabetes are and how
they can be prevented
What is Diabetes?
Diabetes Mellitus (sugar diabetes) is a
disease characterized by high levels of
sugar (glucose) in the blood
Fasting glucose ≥ 7.0 (mmol/L)
Blood sugar and health
Sugar (glucose) is
an important source
of energy
What is eaten is
absorbed into
the blood
Insulin is produced
by the pancreas when
blood sugar is high
Insulin keeps blood
sugar level within
the normal range
for health
Islet of Langerhans:
Pancreas contains
insulin-making
cells in “islets”
Insulin
b-cells
Diabetes in a ‘nutshell’

Insufficient insulin to meet the body’s needs

Either a complete lack (type 1) or relative lack (type 2)

Results in raised blood glucose levels

Untreated diabetes results in short-term symptoms and
serious long-term complications

Treatment aims to keep blood glucose levels as close to the
normal range as safely possible
Complications of Diabetes

Short term:
–
–
–
–

Symptoms of diabetes
Dehydration
Diabetic Coma
Infections
Long term:
–
–
–
–
–
Kidney
Eye
Heart
Circulation
Amputation
Symptoms of Diabetes
People with diabetes often have typical complaints
(symptoms):

Thirst and frequent drinking

More frequent urination, particularly at night

Unexplained weight loss

Fatigue

Blurred vision

Frequent infections : skin, genital
Case 1









JN
32 year old male
Referred to Emergency Dept by GP
Complaining of thirst, excessive urination, half stone
weight loss in the last 6 weeks
No relevant past history
First cousin has diabetes on insulin
On no regular medications
Thin man
Blood sugar level = 24.7 mmol/L
What type of diabetes does
JN have?
There are 2 main types of diabetes:

Type 1 (15%): Due to total lack of insulin – insulin
treatment is required for life

Type 2 (85%): Plenty of insulin which does not work
very well in the body. Insulin treatment may be
required at some stage but is not required in all
patients
Differences between type-1 and
type-2 Diabetes Mellitus







Type 1
Young age
Normal BMI, not obese
No immediate family
history
Short duration of
symptoms (weeks)
Can present with diabetic
coma (diabetic
ketoacidosis)
Insulin required








Type 2
Middle aged, elderly
Usually overweight/obese
Family history usual
Symptoms may be present
for months/years
Do not present with
diabetic coma
Insulin not necessarily
required
Previous diabetes in
pregnancy
These differences are not absolute
JN

Young age
 Thin
 No immediate family history
 Short duration of symptoms
All point to probable type-1 diabetes

Insulin treatment required
The Miracle of Insulin
Patient J.L., December 15, 1922
February 15, 1923
Treatment of Type-1 Diabetes
Mellitus:

Insulin must be administered
into the subcutaneous pocket
between fat & muscle & avoid
injection into fat or muscle.
 Can be administered by
needle and syringe or by pen
device
Alternative way to deliver insulin treatment:
Continuous insulin infusion (insulin pump)
Islet replacement treatment

Aim to replace the need for insulin
treatment
 (Kidney) Pancreas transplantation
 Islet transplantation – not available in
Ireland
 Anti-rejection drugs required
 Stem cell transplantation - experimental
Case 2

Ms AJ, a 45 year old woman is concerned she may have
diabetes
 She had diabetes during her last pregnancy managed with diet
 Lately she has been feeling tired but otherwise has no
complaints
 Her mother and one of her two sisters already have diabetes
treated with tablets
 She has been overweight since her last pregnancy and has
taken a tablet for blood pressure for the last 2 years
 She is obese, body mass index 34.5
 Blood pressure is 140/90 but otherwise her examination is
normal
 She undergoes a testing and her fasting glucose is 9.4 mmol/L
 Obese, strong family history, aged in 40s, previous history of
diabetes in pregnancy all point to type-2 diabetes
Natural History of Type 2 Diabetes
Normal
Insulin
resistance
Insulin
secretion
After meal
glucose
Fasting
glucose
Prediabetes
Type 2 diabetes
Increasing insulin
resistance
Hyperinsulinemia,
then islet cell failure
Abnormal
glucose tolerance
High sugar levels
Adapted from International Diabetes Center (IDC), Minneapolis, Minnesota.
Treatment of Type-2 Diabetes
Diet/
exercise
Oral
monotherapy
Oral
combination
Oral
+/- insulin
Insulin
Diet and exercise my control condition for some time
Variety of tablets available when diet exercise no longer work
Tablets can be used in combination with each other or with
insulin
Insulin can also be used alone
Prevalence of Diabetes

Diabetes is very common

It is becoming more common
(particularly type-2)

It affects about 200,000 Irish people

10% of the health budget spent on
diabetes
Reason for increasing prevalence
of type-2 diabetes
The disease is reaching epidemic proportions
because:

Rates of overweight/obesity have increased

We have become a physically inactive species

Our diets are increasingly unhealthy
Overweight and obesity are diagnosed by
measuring weight and height (Body Mass
Index (BMI)):
Weight in Kg
BMI =
Height in metres2
Normal = 20-25
Overweight = 25-30
Obese = more than 30
Everyone should know their BMI!
Can Diabetes be Prevented?
To be able to prevent a disease we need to be able to
indentify people at particular risk of developing it
Risk factors for type 2 diabetes
Certain people are more at risk of diabetes:

Those who are overweight/obese

People with a family history of diabetes

Women who had diabetes during pregnancy or
have had a baby weighing more than 9lbs

Physically inactive people

Certain ethnic groups (african, american indian,
asian)

People who have high blood pressure or high
cholesterol

Age more than 45 years
Can Diabetes be Prevented?
Risk of Type 2 Diabetes can be reduced:

Losing weight

Taking regular exercise : walking for 30 mins per day

Eating healthier food:
 Less fat (burgers, fries, crisps, sweet foods)
 More fibre (fruit and vegetables, wholegrain
alternatives for rice, bread)

Cutting down on alcohol consumption
Ultimate aim is to reduce the longterm complications
Can the longterm complications
be prevented?

Type-1
– 1993: Study showed for the first time that good sugar
control can prevent long term complications affecting
eyes/kidneys/nerves

Type-2
– 1998: Similar study showed same conclusion for type-2

Important therefore to know that sugar control is
good and monitor frequently
Diabetes Mellitus: Self Monitoring
SMBG

Patients can draw blood
frequently to monitor
their glucose levels.

A glucose monitor is
used to check the sugar
as required






Glycosylated Hemoglobin:
HbAlc
Blood test that measures the amount of glucose that
has been incorporated into the hemoglobin protein
of the red blood cell (RBC).
Reflects the lifespan of a RBC, so test will reveal
the effectiveness of diabetes therapy for the
preceding 8-12 weeks.
HbA1c levels remain more stable than sugar levels.
Not affected by short-term fluctuations in sugar
Normal is 4-6%
Evaluated periodically (1-2 per year if well
controlled, more frequently if not)
A1c and relative risk of
complications (type 1 diabetes) :
20
Retinopathy
Nephropathy
Neuropathy
Microalbuminuria
Relative Risk (%)
15
13
Aim for AIc of < 7%
11
9
7
5
3
1
6
7
8
9
A1c (%)
10
11
12
DCCT, Diabetes Control and Complications Trial.
1. Adapted from Skyler JS. Endocrinol Metab Clin North Am. 1996;25:243-254.
2. DCCT. N Eng J Med. 1993;329:977-986.
3. DCCT. Diabetes. 1995;44:968-983.
How to prevent the complications
Factors other than blood sugar increase likelihood of
complications and should be managed
Complications can be delayed/prevented by:

Controlling blood sugars: sticking to diet/exercise
programme, taking medication as prescribed

Controlling blood pressure: diet, salt restriction,
medication

Controlling cholesterol levels: diet, statin tablets

Stopping smoking

Taking aspirin?
Useful websites

Diabetes Federation of Ireland:
– www.diabetes.ie

American Diabetes Association
– www.diabetes.org

Irish Nutrition and Dietetic Institute
– www.indi.ie

Juvenile Diabetes Research Foundation
– www.jdrf.org