OVERVIEW OF DIABETES
MELLITUS
PREPARED BY MR. ABHIJIT DAS
DIABETES MELLITUS
Diabetes mellitus, commonly referred to as
diabetes, is a chronic metabolic disorder characterized by high blood glucose levels (hyperglycemia) resulting from the body's
inability to produce enough insulin or use it effectively. Insulin is a
hormone produced by beta cells of pancreas that
regulates blood sugar levels by helping glucose enter cells to be used for
energy.
NORMAL PHYSIOLOGY
Here's a brief overview of the normal
physiology in the body when you eat carbohydrates:
1.
Carbohydrate intake: When
you eat carbohydrates, they are broken down into glucose (a type of sugar) in
the digestive system.
2.
Glucose absorption into
the blood: The glucose is then absorbed into the bloodstream and transported to
various organs and tissues in the body.
3.
Glucose goes to pancreas:
Then glucose goes to the pancreas, an organ located behind the stomach, which
plays a crucial role in regulating blood sugar levels.
4.
Beta cells of pancreas
release insulin: In response to the increase in blood glucose levels,
specialized cells in the pancreas called beta cells release insulin into the
bloodstream.
5.
Insulin reduces blood
glucose level: Insulin helps the body's cells to absorb glucose from the blood,
which reduces the concentration of glucose in the bloodstream. This process is
important for maintaining normal blood sugar levels and providing energy to the
body's cells.
6.
Glycogen storage: Any
excess glucose that is not immediately used for energy is converted into
glycogen and stored in the liver and muscles for future use.
7.
Blood sugar regulation:
Overall, the release of insulin helps to regulate blood sugar levels and
prevent hyperglycemia (high blood sugar levels) or hypoglycemia (low blood
sugar levels).
TYPES OF DIABETES MELLITUS
TYPE I
In Type 1 diabetes, the immune system mistakenly attacks and destroys the
insulin-producing beta cells in the pancreas, leading to:
- Little
or no insulin production
- Elevated
blood glucose levels
- Cells
cannot take up glucose for energy
- Increased
hunger and thirst
- Frequent
urination
- Weight
loss despite increased appetite
- Fatigue
and weakness
- Blurred
vision
- Increased
risk of diabetic ketoacidosis (DKA) if left untreated.
TYPE II
In Type 2 diabetes, the body becomes
resistant to insulin and/or the pancreas fails to produce enough insulin to
meet the body's needs. The insulin receptor on cells may also become damaged,
leading to further insulin resistance and impaired glucose uptake by cells.
1.
Insulin resistance: Cells
become less responsive to insulin, leading to elevated blood glucose levels.
2.
Impaired insulin
secretion: The pancreas may not produce enough insulin to overcome insulin
resistance, exacerbating high blood glucose levels.
3.
Abnormal glucose
production: The liver may produce too much glucose, further contributing to
elevated blood glucose levels.
4.
Hormonal imbalances:
Hormones involved in glucose regulation, such as glucagon, amylin, and
incretins, may be disrupted in type 2 diabetes.
5.
Beta cell dysfunction:
Over time, beta cells in the pancreas may become damaged or exhausted, further
reducing insulin production.
TREATMENT OPTIONS
Treatment options for diabetes may
include:
- Lifestyle
modifications such as healthy eating, physical activity, and weight loss
- Medications
such as metformin, sulfonylureas, and insulin
- Regular
monitoring of blood glucose levels
- Managing
other health conditions that can affect diabetes, such as high blood
pressure and high cholesterol
- Diabetes
education and support from healthcare professionals and support groups
LIFE THREATENING CONDITIONS IN DIABETES
DIABETIC KETOACIDOSIS
Diabetic ketoacidosis
(DKA) is a serious complication of uncontrolled diabetes, typically seen in
people with Type 1 diabetes, but it can also occur in people with Type 2
diabetes.
In DKA, the body's insulin deficiency
leads to a state of starvation, causing the body to break
down fats for energy. This process produces acidic
byproducts called ketones, which can
accumulate in the blood and lead to a life-threatening condition known as
ketoacidosis.
The buildup of ketones can cause the blood to become acidic, leading to
symptoms such as nausea, vomiting, abdominal pain, confusion, and eventually
coma.
DKA can also cause dehydration, electrolyte imbalances, and damage to various
organs, such as the brain, kidneys, and heart.
GLUCOSE TOLERANCE TEST
A Glucose Tolerance
Test (GTT) is a diagnostic test used to evaluate how the body processes glucose (sugar). It is often
used to diagnose diabetes or gestational diabetes (a form of diabetes that
occurs during pregnancy). Here is an overview of the patient preparation, procedure, and reference range for a glucose
tolerance test:
Patient Preparation:
1. Dietary Restrictions: Prior
to the test, the patient is usually instructed to follow specific dietary
restrictions. Typically, this involves fasting for
a specified period (usually 8-12 hours)
before the test. During this fasting period,
the patient should
avoid consuming any food or beverages except
for water.
2. Medication: Patients
may need to temporarily discontinue certain
medications that can affect blood
sugar levels. It's important to follow your healthcare provider's instructions
regarding medication adjustments before the test.
3. Physical Activity: Patients should avoid strenuous physical
activity in the days leading up to the test, as it can
affect glucose metabolism.
4. Inform Your Healthcare Provider: Inform
your healthcare provider about any medications you are taking, any medical
conditions you have, and whether you have had any recent illnesses or surgeries. This information can help ensure accurate test results and
appropriate interpretation.
Procedure:
1. Baseline Blood Sample: The glucose
tolerance test typically begins with a baseline fasting blood sample.
This sample is collected after the patient has fasted for the specified period
(usually overnight).
2. Glucose Drink: After
the fasting blood sample is collected, the patient
is given a glucose solution to drink. The solution contains
a measured amount of glucose (usually 75 grams, but this may vary depending on
the specific test).
3. Wait Period: After
drinking the glucose solution, the patient is asked to remain seated or
reclined in a comfortable position while waiting for a specific amount
of time (usually 2 hours). During this time, it's essential
to
stay relatively still and avoid
eating, drinking, or engaging in strenuous
activities.
4. Additional Blood Samples: Blood samples
are collected at regular intervals (usually every 30 minutes)
during the waiting period. These samples are used to measure
blood glucose levels at different time points.
5. Post-Test Observations: After
the test is complete, your healthcare provider will review the results
and discuss them with you. Abnormal
results may indicate impaired glucose tolerance or diabetes.
Reference Range:
The reference range for a glucose tolerance test can vary depending
on the laboratory and the specific criteria
used. Generally, here are some guidelines for interpreting the results:
·
Fasting Blood Sugar (Fasting
Plasma Glucose): Typically, a fasting blood sugar level of less than 110 milligrams per deciliter (mg/dL) is considered
normal.
· 2-Hour Post-Glucose Load: After consuming the glucose solution, a blood sugar level of less than 140 mg/dL is typically considered normal. Values between 140 and 199 mg/dL may indicate prediabetic stage, while values of 200 mg/dL or higher often suggest diabetes.
ESTIMATION OF GLUCOSE BY ‘GOD-POD’ METHOD
Definition: The GOD-POD
method is a chemical assay that uses enzymes (glucose
oxidase and peroxidase) to convert glucose to hydrogen peroxide, which
then reacts with a chromogenic
reagent to produce a colored compound. The intensity of the color is proportional to the glucose concentration.
Procedure:
1. Sample Preparation:
·
Collect a blood sample
and prepare it for analysis, ensuring it is well-
mixed and at an appropriate temperature.
2.
Addition of Glucose Oxidase
(GOD):
·
Add a known volume of a glucose oxidase
solution to the blood sample. Glucose oxidase
catalyzes the conversion of glucose to hydrogen peroxide.
3. Incubation:
Incubate the mixture at a specific
temperature (usually 37°C) for a predetermined time (typically 5-10
minutes). This allows glucose oxidase to convert
glucose to hydrogen peroxide.
4. Addition of Peroxidase:
·
Add a
known volume of a peroxidase solution and a
chromogen to the mixture.
5. Incubation:
·
Incubate the mixture again at the same temperature for a specific
time to ensure complete reaction.
6. Change of Color:
·
After the second incubation, the reaction will produce a colored
compound. The color intensity is directly proportional to the amount of
glucose in the sample.
7. Color Measurement Using
Spectrophotometer:
·
Use a spectrophotometer to measure
the absorbance of the colored solution at a specific wavelength
(typically around 540 nm).
8. Result Reporting:
·
Report the glucose concentration in the sample in the appropriate units (e.g., mg/dL).