The term Diabetes mellitus describes a metabolic
disorder of multiple aetiology characterized by chronic
hyperglycaemia with disturbances of carbohydrate, fat
and protein metabolism resulting from defects in
insulin secretion, insulin action, or both.
The effects of diabetes mellitus include long–term
damage, dysfunction and failure of various organs
Type 1 Diabetes
Type 2 Diabetes
- blood glucose levels rise due to
- Absolute deficiency of insulin due
to destruction of β cells of
- results in insulin dependence
- commonly detected before 30
1) Lack of insulin production
2) Insufficient insulin
action (resistant cells)
- commonly detected after 40
- effects > 90%
- eventually leads to β-cell failure
(resulting in insulin dependence)
Normal BMI, not obese
No immediate family
Short duration of
Can present with diabetic
Middle aged, elderly
Family history usual
Symptoms may be present
Do not present with
Insulin not necessarily
Previous diabetes in
characteristic symptoms are increased thirst, polyuria,
blurring of vision, unexplained weight loss, fatigue
and recurrent infections such as candida.
In its most severe forms, ketoacidosis or a non-ketotic
hyperosmolar state may develop and lead to stupor,
coma and, in absence of effective treatment, death.
Symptoms of diabetes
Diagnosis of Diabetes mellitus
Screening of Diabetes mellitus
Assessment of glycemic control
Assesment of associated long term risks
Management of acute metabolic complications
The diagnosis of diabetes in an asymptomatic subject
should never be made on the basis of a single
abnormal blood glucose value.
For the asymptomatic person, at least one additional
plasma/blood glucose test result with a value in the
diabetic range is essential, either fasting, from a
random (casual) sample, or from the oral glucose
tolerance test (OGTT)
-Glucose may be estimated in either plasma or
-The glucose concentration in whole blood is
approximately 15% lower than the glucose
concentration in serum or plasma, because the
volume of distribution of glucose is lower, as
erythrocytes contain less free water than plasma.
-Samples for glucose can be obtained either by
veinpuncture or by a fingerprick technique
(collected in capillary tubes).
-Blood cells continue to metabolize glucose after
veinpuncture and serum or plasma must be
refrigerated and separated from the cells within 1
hour to prevent substantial losses of glucose by the
-A preservative that inhibits glycolysis should be
used (sodium fluoride, together with potassium
oxalate as an anticoagulant, is used for this
Fasting Plasma Glucose Test (FPG)
Fasting morning blood glucose is the best initial test.
It is a cheap and fast test done after 10-16 hrs of
* fasting B.G.L. 100-125 mg/dl signals pre-diabetes
* >126 mg/dl signals diabetes
-The two-hour postprandial glucose measurement is
often used in conjunction with the fasting plasma
-The patient is advised to consume a meal that
contains approximately 75 grams of
-Two hours after eating, a blood sample is drawn for
plasma glucose measurement.
-A glucose value greater than 200 mg/ dl indicates
-The OGTT is the most sensitive test for the diagnosis
It refers to the ability of the body to metabolize
-A sample of the patient's blood is drawn after an over
-The patient then consumes 75g of a glucose solution
and blood is drawn every 30 minutes for two hours.
Impaired glucose tolerance is diagnosed with a plasma
glucose between 140 and 200 mg/dL (7.8 and 11.1
mmo1/L) at 2 hours time point in the test ( prediabetes)
A plasma glucose greater than or equal to 200 mg/dL
(11.1 mmol/L) at the 2-hour
time point indicates diabetes mellitus.
Gestational diabetes is considered present when the
values of the OGTT are greater than the following;
fasting, 105 mg/dL (5.8 mmo1/L)
1 h, 190 mg/dl (10.6 mmo1/L)
2 h, 165 mg/dL (9.2 mmo1/L)
If serum glucose level exceeds the renal glucose
threshold (180 mg/dl), it appears in urine
(GLUCOSURIA) as in diabetes mellitus.
Glucose can be detected in urine using the specific test
strips that contain glucoseoxidase, peroxidase, and a chromagen.
-Other carbohydrates using Benedict's and Fehling's
HbA1c is the largest subfraction of normal HbA in both
diabetic and non-diabetic subjects and is formed by the
reaction of the-beta chain of HbA with glucose.
This fraction reflects the concentration of glucose
present in the body over a prolonged time period.
The measurement of glycated haemoglobin therefore
gives an indication of the overall degree of blood
glycaemic control, in contrast to glucose measurements
which give information for a single time-point.
HgA1C is therefore the gold standard test
All treatment decisions for Type 2 Diabetics
should be based on Hb A1C levels
There appears to be a direct relationship between
cardiovascular risk and HbA1C.
The goal is to achieve an HbA1C as low as possible,
preferably less than 7.0%, without causing
HbA1C > 8 mmol/L is a sign of inadequate control
for most people