Diabetes mellitus (Type 1): Clinical sciences

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Introduction0:00–1:26

Diabetes mellitus is a chronic condition where tissue cells can’t properly absorb and use glucose, so it stays and builds up in the blood.
Normally, pancreatic islet beta cells produce insulin, which acts on insulin receptors on tissue cells to promote uptake and storage of glucose, amino acids, and triglycerides, as well as stimulate glycolysis, protein synthesis, and lipogenesis.
Now, there are two types of diabetes, type 1 and type 2. In type 1 diabetes, there’s autoimmune destruction of the pancreatic islet beta cells, resulting in severe insulin deficiency and, ultimately, hyperglycemia.
This is in contrast to type 2 diabetes mellitus, where the pancreatic islet beta cells stop properly responding to stimulation to produce insulin, combined with insulin resistance, meaning that the tissue cells aren’t able to appropriately respond to the little insulin that’s still being produced.
In either disease type, the resulting hyperglycemia can cause clinical manifestations ranging from prediabetes and diabetes mellitus, to severe life-threatening conditions, like diabetic ketoacidosis, or DKA, most commonly seen in patients with type 1 diabetes, and, hyperosmolar hyperglycemic state, or HHS, most commonly in type 2 diabetes.Now, if you suspect type 1 diabetes mellitus, you should first perform an ABCDE assessment to determine if your patient is unstable or stable.

Unstable patient1:26–4:38

If the patient is unstable, stabilize the airway, breathing, and circulation. This means that you might need to intubate the patient.
Next, obtain IV access and, if your patient is hypotensive, start IV fluids for volume resuscitation. Finally, put your patient on continuous vital sign monitoring, such as pulse oximetry, blood pressure, and heart rate.
Next, you want to assess for DKA or, less frequently, HHS. Obtain a focused history and physical exam, and order labs, such as point-of-care blood glucose, serum osmolality, BMP, urinalysis, hemoglobin A1c, as well as ABG or VBG.
Patients typically present with fatigue, headache, or dry mouth, polyuria, and polydipsia. They may also be so confused they cannot give an accurate history, so be sure to speak with caretakers and review the chart thoroughly to get an accurate history.
Your patient may also have had a precipitating illness or infection, or have a known history of diabetes mellitus with or without disruption to their diabetes treatment plan.
On the other hand, physical exam might reveal tachypnea, tachycardia, and hypotension in a confused, somnolent patient. The mucous membranes are often dry.
Let’s start by using our labs to help us distinguish between DKA and HSS. In HHS, lab results typically reveal a significantly elevated random blood glucose, more so than DKA, often exceeding 600 milligrams per deciliter.
BMP may reveal hyponatremia and hypokalemia, as well as elevated BUN and creatinine. The serum osmolality is high, usually greater than 320 milliosmoles per kilogram.
Finally, there will be an elevated hemoglobin A1c.On the other hand, DKA, lab results reveal a significantly elevated random blood glucose, exceeding 250 milligrams per deciliter.
BMP may reveal hyponatremia and hypokalemia, as well as elevated BUN and creatinine. There is a normal serum osmolality.
Finally, there will be an elevated hemoglobin A1c, and the ABG or VBG will confirm elevated anion gap metabolic acidosis.
You may also see decreased bicarbonate, hinting at a metabolic acidosis. Urinalysis will show ketones.
In either case, HHS or DKA, management of these individuals includes IV fluid resuscitation to correct dehydration and hyperosmolality, as well as electrolyte repletion.
Additionally, you can start an IV insulin drip, if indicated, and carefully monitor potassium levels. Don’t forget to treat any underlying or precipitating causes!Now that we're done with unstable patients, let’s go back to the ABCDE assessment and discuss stable ones.

Stable patient4:38–5:40

If your patient is stable, first obtain a focused history and physical examination. Your patient might report unintentional weight loss, polydipsia, polyuria, and blurred vision, while family history often reveals autoimmune disorders such as thyroid disease or celiac disease.
On physical exam, you may notice oral thrush or dry mucous membranes. At this point, you should suspect diabetes mellitus, and proceed with labs, such as hemoglobin A1c, a fasting blood glucose, a 2-hour oral glucose tolerance test, or OGTT, and a random blood glucose test.
Keep in mind that not all patients require an OGTT; this is often used when the other values are inconclusive or unclear in making a diagnosis.

Alternative diagnosis and Prediabetes5:40–6:34

Now let’s look at lab results to determine a diagnosis. Now, if the hemoglobin A1c is less than 5.7%, fasting blood glucose is less than 100 mg/dL, blood glucose after the 2-hour OGTT is less than 140 mg/dL, and random blood glucose is less than 200 mg/dL, then you should consider an alternative diagnosis.On the other hand, you should consider prediabetes if the hemoglobin A1c is between 5.7 and 6.5%, fasting blood glucose is between 100 and 126 mg/dL, or blood glucose after the 2-hour OGTT is between 140 and 199, and a random blood glucose is under 200 mg/dL.
Keep in mind that prediabetes typically precedes type 2 diabetes mellitus, and only rarely precedes type 1. Finally, you can make a diagnosis of diabetes mellitus if the hemoglobin A1c is equal to or greater than 6.5%, fasting blood glucose is equal to or greater than 126 mg/dL, blood glucose is equal to or greater than 200 mg/dL after a 2-hour OGTT, or random blood glucose is equal to or greater than 200 mg/dL, Your next step is to determine the underlying mechanism.

Diabetes6:34–7:57

Start by ordering glutamic acid decarboxylase, or GAD65, antibodies, islet cell, or ICA2, antibodies, and C-peptide Levels.
If the GAD65 and ICA2 antibodies are negative and the C-peptide levels are normal, the patient has type 2 diabetes mellitus.
On the other hand, if the GAD65 or ICA2 antibodies are positive and C-peptide levels are low, then the patient has type 1 diabetes mellitus.
Here’s a clinical pearl! Type 1 diabetes mellitus is more common in children and adolescents.
They have increased risk for additional autoimmune conditions. So, in these patients, you want to screen them for other related autoimmune conditions, like Addison disease, celiac disease, and hypothyroidism.

Type 1 DM- Treatment7:57–10:03

Alright, now that you’ve diagnosed type 1 diabetes, you’ll need to begin insulin therapy. Start with 0.3 to 0.7 units per kilogram per day, divided into multiple daily injections.
Half of the total daily dose of insulin is usually given as a longer-acting, basal form of insulin. This basal dosing is usually constant day to day.
The other half of the total daily dose is used for carbohydrate coverage in each meal and snacks and is known as a bolus dose.
This is done as an insulin to carbohydrate ratio, where usually about one unit will cover so many grams of carbohydrate.
Bolus dosing can also be done based on blood sugar correction, where one unit of insulin drops the blood sugar by a certain amount.
These amounts vary based on the insulin used and the person’s metabolism. Next, your patient will need a blood glucose monitor to check blood sugar levels, ideally before meals.
Your patient should aim for their blood sugar to be between 70 and 180 milligrams per deciliter. Lastly, you will want to provide diabetes self-management education and support, including how to self-administer insulin, monitor and interpret blood glucose levels, and how to recognize, prevent, and treat hypo- and hyperglycemia.
Your patient should also work with a dietician to learn how to count carbs, determine an insulin-to-carb ratio for pre-meal insulin dosing, and how to adjust insulin dosing for changes in routine, like illness and increased physical activityHere’s a clinical pearl to keep in mind!
Patients who require frequent glucose testing may be good candidates for a continuous glucose monitor, or CGM, which monitors blood glucose around the clock.
Similarly, an insulin pump is a wearable device that provides a continuous insulin infusion, and some CGMs and insulin pumps even communicate in real time.
Okay, now after your patient has been prescribed an insulin regimen and has completed self-management education, follow up in 3 months to reassess hemoglobin A1c.

Follow up10:03–10:54

If they are responding adequately to treatment, their hemoglobin A1c will be below 7%. You’ll then continue their current treatment, repeat hemoglobin A1c levels every 3 months, and screen patients annually for diabetic retinopathy, neuropathy, and nephropathy.
On the other hand, if the hemoglobin A1c is greater than or equal to 7%, this is an inadequate response to treatment, so adjust the insulin regimen with the goal of improved blood glucose control.
Again, you’ll repeat hemoglobin A1c every 3 months to trend and screen patients annually for diabetic retinopathy, neuropathy, and nephropathy.Alright, as a quick recap… If you suspect type 1 diabetes mellitus, first you should determine whether your patient is unstable or stable.
Unstable patients might have life-threatening complications like DKA or HHS, which requires management with IV fluid resuscitation, electrolyte repletion, as well as IV insulin drip, if indicated.

Review10:54–11:51

In stable individuals, you should obtain a hemoglobin A1c, a fasting blood glucose, an OGTT, and a random blood glucose, and if appropriately elevated, you can make a diagnosis of diabetes mellitus.
You’ll then use GAD65 antibodies, ICA2 antibodies, and C-peptide levels to determine whether the patient has type 1 diabetes and, if so, start the patient on daily basal and bolus insulin.
You’ll then follow the patient for adequate response and screen them annually for diabetic retinopathy, neuropathy and nephropathy.
one diabetes And if so start the patient on a daily basal and bolus insulin you will then follow the patient for adequate response and screen them