Diabetes mellitus is a condition in which the body’s ability to respond to insulin or produce insulin is impaired. This results in abnormal carbohydrate metabolism and elevated blood glucose levels.

There are different types of diabetes: 

  • Type 1 DM – Thought to be caused by an autoimmune reaction that destroys the insulin-producing cells of the pancreas. Individuals with type 1 diabetes are reliant on insulin. About 5 to 10% of individuals with diabetes have type 1 and it generally manifests in childhood or young adulthood.
  • Type 2 DM – In type 2 diabetes, the pancreas doesn’t produce enough insulin, or the body’s ability to utilize insulin is impaired (or both). Most people with diabetes have type 2 and, unlike type 1, it is considered preventable and reversible. 
  • Latent autoimmune diabetes in adults (LADA) – This form of diabetes is similar to type 1, only it occurs in adulthood and gradually worsens over time. You may hear this referred to as type 1.5 diabetes.
  • Gestational diabetes – Occurs in pregnant individuals who do not have a history of diabetes. We’ll talk about gestational diabetes in another lesson.

Physiology Review

Blood glucose levels increase in the body for a variety of reasons, one of the most common being with the intake of nutrition (mainly carbohydrates). Other causes of blood glucose elevations include medications (such as corticosteroids), stress, and infection. In normal physiology, the pancreas secretes insulin in response to elevated blood glucose levels. 

Insulin is a hormone that helps the body use sugar for energy by moving glucose from the bloodstream into the cells. Think of insulin as a key that unlocks the cell so glucose can enter. When insulin levels are inadequate (or when the body has an impaired response to insulin), the glucose can’t get into the cells to provide energy and, instead, builds up in the bloodstream causing hyperglycemia. 

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In type 1 diabetes, which is insulin dependent diabetes, the pancreas does not produce insulin. This is believed to be due to the body’s own immune system attacking the beta cells of the pancreas, which can be a result of genetics or environmental factors such as viruses. 

In type 2 diabetes, there’s either not enough insulin being released, or, very commonly, the cells in the body are resistant to the insulin that is present, making it more difficult for the insulin to unlock the cell so the glucose can enter. 

In both types of diabetes, blood glucose does not enter the cell where it can provide energy to the body. Instead, it builds up in the bloodstream causing hyperglycemia. Over time, elevated blood glucose levels lead to a wide range of problems including increased risk for infection, delayed wound healing, nerve damage leading to neuropathy, hypertension, foot complications that can significantly affect mobility, renal failure, cardiovascular disease, blindness and stroke.

Acute complications of diabetes include diabetic ketoacidosis and hyperglycemic hyperosmolar state, both are life-threatening emergencies that require prompt medical intervention. 

Now that you have some background knowledge of diabetes, let’s dive into it in more detail using the Straight A Nursing LATTE method.

L: How does the patient LOOK?

The three classic signs of diabetes are the three Ps: polyuria, polydipsia, and polyphagia. One additional classic sign is weight loss. Why does this happen? 

Polyuria – As the amount of blood glucose in the blood exceeds what the kidneys can handle, excess glucose is excreted in the urine, causing osmotic diuresis (polyuria). 

Polydispsia – Hyperglycemia increases the osmolarity of the blood, meaning it’s more concentrated. This, along with polyuria, triggers the thirst center in the brain.

Polyphagia – Without an energy source in the cells, the body thinks it is starving and this triggers hunger signals in the brain.

Weight loss – Without sugar to use for energy, the body breaks down fat and protein which leads to weight loss.

Other things you may notice about a patient with diabetes include fatigue, blurred vision, wounds that don’t heal, numbness/tingling in the hands and feet due to peripheral neuropathy, malformed feet (a condition called Charcot foot), and acanthosis nigricans (dry, dark patches of skin usually located at the neck, groin and armpits). 

In DKA, which is a complication of diabetes, the patient may have decreased LOC, fruity-smelling breath and rapid, deep breathing called Kussmaul respirations.

Note that the signs and symptoms of diabetes are not just related to hyperglycemia. Hypoglycemia can occur as well. Common signs and symptoms of hypoglycemia include shakiness, irritability or confusion, sweating, palpitations, headache, dizziness, and hunger.

Not sure what to focus on when studying? Download the FREE LATTE method template

A: How do you assess the patient?

The key assessment for a patient with diabetes is to measure blood glucose. This is most often done using a fingerstick blood glucose test, but can also be measured from a lab draw. See the next section in the LATTE method for more details about blood glucose levels. 

Other key assessments for a patient with diabetes include: 

  • Monitoring for signs of hypoglycemia
  • Assess skin for non-healing wounds, especially on the feet
  • Assess for numbness or tingling associated with peripheral neuropathy
  • Monitor I/O, especially if renal function is impaired

T: What TESTS are utilized in diabetes?

The main test utilized in the evaluation of diabetes is blood glucose and there are several types of tests: 

  • Fasting blood glucose – This test measures the glucose level after a period of not eating (typically overnight). A fasting blood glucose less than or equal to 99 mg/dL is normal, a level between 100 and 125 mg/dL is considered prediabetes, and a level above 125 mg/dL is considered to be diabetes.
  • Random blood glucose – This test measures the glucose level at a random time not related to meal times. A level above 200 mg/dL is diagnostic for diabetes.
  • Glucose tolerance test – This test measures your blood glucose level after ingesting a specified amount of glucose. Tests are typically conducted 1, 2 and possibly also 3 hours after ingesting the glucose. If, at the 2-hr check, the blood glucose is below 140 mg/dL this is a normal result. If it is between 140 to 199 mg/dL at that two hour mark, this is considered prediabetes, and anything at 200 mg/dL and above is diabetes.

The HbA1c looks at the average blood glucose over the past three months. A normal result is less than 5.7%, prediabetes is a result of 5.7 to 6.4%, and a result of 6.5% or higher is considered diabetes.

T: What TREATMENTS are provided to treat diabetes?

Type 1 diabetes is treated with insulin and type 2 diabetes is treated with insulin, non-insulin antidiabetic medications, and lifestyle changes.

Insulin therapy is the mainstay of diabetes treatment. It involves various types of insulin and treatment plans vary from patient to patient: 

  • Sliding scale insulin – The dose of insulin is dependent upon the blood glucose level. You may also hear this called “correctional” insulin.
  • Nutritional insulin – Some patients will get a dose of insulin with each meal, which is calculated based off how many carbohydrates are in the meal.
  • Basal insulin – This type of insulin provides steady, continuous blood glucose control.
  • IV insulin – In severe cases, the patient may need a continuous insulin infusion.

Insulin is categorized by how quickly it takes effect. 

  • Rapid-acting insulin takes effect within 10 to 15 minutes and is typically administered just prior to eating. Examples of rapid insulin are insulin lispro (Humalog) and insulin aspart (Novalog).
  • Short-acting insulin has an onset of 30 to 60 minutes and is often used in continuous IV infusions. An example of a short-acting insulin is Humulin R or “regular insulin.”
  • Intermediate insulins are used once or twice a day and are combination mixtures of insulin which contain protamine, an ingredient that causes them to have longer-lasting effects than rapid and short-acting insulins. The protamine is what gives intermediate insulins a cloudy appearance. While you can mix intermediate insulin with a more rapid insulin, how you draw them up is very important! Draw up the shorter-acting insulin first so you don’t accidentally inject protamine into the short-acting insulin vial. You may hear this referred to as “clear before cloudy” since shorter-acting insulins are clear and the intermediate insulin is cloudy. Examples of intermediate insulins are Humulin N and Novalin N. You may hear these simply referred to as “NPH”
  • Combination insulin is a mixture of a shorter and intermediate-acting insulin. These are named by the percentage of each type of insulin. For example, Humulin 70/30 has 70% intermediate-insulin and 30% short-acting insulin.
  • Basal insulins take effect in about an hour and have no peak. They provide steady blood glucose control for up to 42 hours. Examples of basal insulin are insulin glargine (Lantus) and insulin degludac (Tresiba).

There are also quite a few non-insulin PO and injectable medications, which are discussed in this article. One very common antidiabetic medication used in the treatment of type 2 diabetes is metformin. 

Metformin works by decreasing gluconeogenesis and making skeletal muscle tissue more sensitive to insulin. A common adverse effect with metformin is GI upset, though it can also cause weight loss which is often considered a desirable effect. A key thing to know about metformin is that it is not compatible with IV contrast and will be held for 48 hours after contrast is used in order to prevent serious renal damage. 

Other treatments for diabetes include nutrition, exquisite foot care, the treatment of hypoglycemia and lifestyle modifications.


The key components of a diabetic diet are to avoid added sugars, eat regular meals, and keep carbohydrate counts consistent. In the clinical setting this is typically about 60 g carbohydrate per meal. The American Diabetes Association recommends the Diabetes Plate Method where half the plate is non-starchy vegetables, a quarter of the plate is complex carbohydrate foods, and a quarter of the plate is dedicated to protein foods.

Exquisite foot care

 This involves washing the feet daily and drying thoroughly (especially between the toes). Nail care should be conducted after bathing or showering when the nails are softest and often patients are advised to just use a nail file since clippers can cut the skin and cause a difficult-to-treat wound. If the patient is trimming the nails, they are to be cut straight across to help reduce the risk of cuts. It’s also important to avoid applying lotion between the toes where it could cause skin breakdown.

Treatment of hypoglycemia

Patients with diabetes, and especially those taking insulin, are at high risk for hypoglycemia. A standard treatment protocol is to provide a form of glucose when the blood sugar is 70 or less. If the patient can swallow safely, this is often in the form of 15 g carbohydrate such as 4 oz of juice. If the patient cannot swallow, then 50% dextrose is administered IV or glucagon is administered SubQ or IM. In any case, check the blood sugar again in fifteen minutes and continue treatment as needed.

Lifestyle modifications

Though lifestyle modifications cannot reverse type 1 diabetes, they can help to prevent large spikes in blood sugar and help prevent complications. In patients with type 2 diabetes, lifestyle modifications can lessen the severity of the disease, reduce dependence on insulin and, in some cases, even reverse the disease. Patients with diabetes are encouraged to maintain a healthy weight, get regular exercise, eat a balanced diet (such as ADA’s Diabetic Plate Method), manage cholesterol levels, stop smoking, limit alcohol intake, manage stress, and get regular checkups to monitor for potential complications such as heart disease, renal disease, and diabetic retinopathy.

E: How do you EDUCATE and EVALUATE the patient with diabetes?

There is a lot of education for patients with diabetes. Some key things to teach are:

  • How and when to measure blood glucose levels
  • How to draw up the correct dose of insulin
  • How to recognize and manage hypoglycemia
  • Proper nutrition such as the ADA Diabetic Plate Method
  • Diabetes foot care
    • Proper foot hygiene
    • Avoid going barefoot or wearing sandals
    • Wear clean, dry socks
    • Check shoes for debris before wearing
    • Get regular foot exams
  • When to seek medical care (such as with DKA, a wound that won’t heal or a new wound on the foot, changes in vision, or any other signs of a complication)
  • How to manage blood glucose when ill (a “sick-day” protocol). 
    • Check blood sugar more frequently, typically every two to four hours
    • Continue taking insulin for elevated blood sugar even if vomiting or not eating (the stress of illness will causes blood sugar levels to rise)
    • Stay hydrated
    • If unable to eat solids, include fluids that contain carbohydrate such as fruit juice or tea with honey.
    • Check urine for ketones, which are present in ketoacidosis. Another key sign of diabetic ketoacidosis is rapid, deep breathing (Kussmaul respirations).
    • The patient should seek medical care if they are unable to take their insulin, if blood sugars remain elevated despite insulin therapy or if they are showing signs of dehydration or ketoacidosis.

How do you evaluate the effectiveness of your interventions? In hyperglycemia, the goal is euglycemia (a normal blood glucose level). Other indicators that interventions have been effective could be: 

  • The patient is free of diabetes complications (or free from worsening complications)
  • The patient states an understanding of how and when to take medications
  • HbA1c < 5.7%

For more lessons on diabetes and associated concepts, click here.

Take this topic on the go by tuning in to episode 304 of the Straight A Nursing podcast. Listen from any podcast platform, or straight from the website here.


The information, including but not limited to, audio, video, text, and graphics contained on this website are for educational purposes only. No content on this website is intended to guide nursing practice and does not supersede any individual healthcare provider’s scope of practice or any nursing school curriculum. Additionally, no content on this website is intended to be a substitute for professional medical advice, diagnosis or treatment.


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