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Diabetes Mellitus Nursing Care & Pathophysiology

Updated: May 23, 2022

Diabetes Mellitus is a cluster of metabolic conditions that are caused by an increase of glucose in the blood. In these notes, we'll be going over the diabetes mellitus pathophysiology and the nursing care required with such patients.

Overview of Diabetes

Blood glucose (aka. blood sugar) is the primary source of energy for our body, and we get this through the food and drinks that we ingest.

Now, in most cases, our body controls the blood glucose level and keeps it within a healthy range. But in diabetes mellitus, the body has problems moving the blood glucose into the cells, so the body ends up with too much glucose in the blood and very little of it in the cells. This problem is known as Diabetes, and if left untreated can develop into serious complications.


The body regulates the level of glucose in the blood by the help of two hormones: insulin and glucagon. Insulin decreases the blood glucose levels, while glucagon increases the blood glucose levels.

Both insulin and glucagon are made in a group of cells within the pancreas known as Islets of Langerhans. These cluster of cells contain alpha cells which secrete glucagon, and beta cells which secrete insulin. Now insulin decreases the level of glucose in the blood by attaching itself to insulin receptors which are found in the cell membrane of muscle cells and adipose (fat) tissue. When the insulin receptors are activated, glucose is sucked into the cells. So, it leaves the bloodstream and enters into the cells.

The Glucagon hormone acts oppositely. It helps the liver to produce new glucose molecules and then pushes these glucose molecules into the bloodstream.

As we already mentioned, Diabetes Mellitus occurs when glucose in the blood becomes too high. But there are different ways that this can happen, and so Diabetes Mellitus is split into different types:

Type 1 Diabetes

10% of the people with Diabetes have Type 1, and it is mostly found in children. This type of Diabetes occurs because the body’s own immune system attacks the beta cells in the pancreas.  As a result, not enough insulin is produced, leaving the glucose to accumulate in the bloodstream.

Type 2 Diabetes

The most common form of Diabetes is Type 2, and it’s mostly found in middle-aged or old people. In type 2 diabetes, the beta cells produce insulin, but the body doesn’t respond to it appropriately.

In a normal situation, when insulin is produced, it attaches to the cell membrane. This attachment signals the cell to activate the Glucose Transporters, and they suck in the glucose from the bloodstream. But in Type 2 diabetes, the cell does not realise that insulin has attached to the membrane. So it does not activate the Glucose Transporters, which means that no glucose will be sucked into the cell. We call this problem insulin resistance.

Gestational Diabetes

Gestational Diabetes occurs in some pregnant women during their third trimester. Research suggests that pregnancy hormones may affect the insulin receptors and insulin’s action. In fact, gestational Diabetes works similarly to type 2 diabetes.

Symptoms of Diabetes:

1. Polyphagia: (Excessive eating)

Since the glucose remains in the blood, the cells will become hungry, and in turn, the body will look for other ways to supply energy. Over time, the body starts to break down fat and muscles to get power, and if left uncontrolled, this leads to weight loss.

Because of this break down of fat and muscle, people with uncontrolled Diabetes will feel hungry very often.

2. Glycosuria: (glucose in the urine)

As the blood circulates through the body, it is filtered through the kidneys. So, if the blood contains too much glucose, the kidneys will try to filter it out of the body by sending it off with the urine.

3. Polyuria: (frequent peeing)

Glucose attracts water because it is osmotically active, and this leads to an increase in urination.

4. Polydipsia: (Thirsty often)

As a result of frequent urination, the body becomes dehydrated more quickly. This means that people with uncontrolled Diabetes will feel thirsty all the time.


A series of blood tests are done to determine whether the patient has Diabetes and which type it is. These include:

  1. Fasting glucose test

  2. Random glucose test

  3. Oral glucose tolerance test

  4. HbA1c test

  5. C peptide test

diabetes mellitus nursing care pancreas

Risk Factors

Type 1 Diabetes

  1. Family history of type 1 diabetes

  2. Auto- immune disorders

Type 2 Diabetes

  1. Obesity

  2. Lack of exercise

  3. Hypertension


1. Lifestyle Changes

The first step when identifying patients with early Type 2 diabetes is to encourage lifestyle changes. These include:

  1. Weight loss

  2. Eating a healthy diet with minimal sugars (don’t forget sugars include: carbohydrates and fruit)

  3. Exercising

  4. Smoking Cessation

2. Oral Hypo Glycaemic Medication

Class: Biguanide

  1. Example: Metformin

  2. Indication: Pre-Diabetes (Early Diabetes)

  3. Mode of Administration: Oral

  4. Mode of Action: Decrease insulin resistance by encouraging insulin uptake in the cells

  5. Side Effects: Nausea; Diarrhea; Lactic Acidosis (Very Rare)

  6. Important: To monitor Vitamin B12 levels, as metformin can decrease it

  7. Contraindication: Chronic Kidney Disease; Heart Failure

Class: Sulfonylureas

  1. Example: Gliclazide

  2. Indication: Type 2 Diabetes

  3. Mode of Administration: Oral

  4. Mode of Action: They increase the volume of insulin that the pancreas naturally secretes

  5. Side Effects: Hypoglycaemia (low blood sugar); Weight Gain

  6. Important: To be taken 30minutes before a meal to avoid hypoglycaemia

  7. Contraindication: Chronic Kidney Disease

Class: Thiazolidinediones

  1. Example:

  2. Indication: Type 2 Diabetes

  3. Mode of Administration: Oral

  4. Mode of Action: Decrease insulin resistance by encouraging insulin uptake in the cells; Decrease the glucose production from the liver, so it decreases the overall blood glucose level

  5. Side Effects: Weight Gain

  6. Contraindication: Heart Failure

3. Insulin Therapy

Insulin therapy is usually given to Type 1 Diabetics or to people with Type 2 Diabetes if the oral medications and lifestyle changes didn’t work

Type: Rapid Acting Insulin

  1. Example: Novarapid

  2. Mode of Administration: Subcutaneous

  3. Onset of Action: 15minutes, lasts up to 8hours

Type: Short-Acting Insulin

  1. Example: Actrapid

  2. Mode of Administration: Subcutaneous; Intravenous (has to be diluted)

  3. Onset of Action: 1 hour, lasts up to 8 hrs

Type: Intermediate Acting Insulin

  1. Example: Humulin N

  2. Mode of Administration: Subcutaneous

  3. Onset of Action: 2hours, lasts up to 18hours

Type: Long Acting Insulin

  1. Example: Insulatard

  2. Mode of Administration: Subcutaneous

  3. Onset of Action: 2 hours, lasts up to 24hours

Type: Mixed Insulin

(short and long acting insulin together)

  1. Example: Mixtard

  2. Mode of Administration: Subcutaneous

  3. Onset of Action: has immediate and long term effects

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