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Course: Health and medicine > Unit 7
Lesson 3: Diabetes- What is diabetes mellitus?
- What is diabetes mellitus?
- Breaking down diabetes
- Types of diabetes
- Pathophysiology - Type I diabetes
- Pathophysiology - Type II diabetes
- Diagnosing diabetes
- Treating type I diabetes
- Treating type II diabetes - Pharmacology
- Treating type II diabetes - A practical approach
- Acute complications of diabetes - Diabetic ketoacidosis
- Acute complications of diabetes - Hyperosmolar hyperglycemic nonketotic state
- Diabetic nephropathy - Mechanisms
- Diabetic nephropathy - Clinical presentation & treatment
- Diabetic retinopathy
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Diagnosing diabetes
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Want to join the conversation?
- I am not very clear on how the diagnosis of diabetes melltius (DM) can help us differentiate if a person has type I DM or type II DM. The presentation of the disease is not very different for either type in the sub-acute and asymptomatic stage, but it is only clear in the acute phase of the disease. However, since this is not very common in the population (thankfully), how can a specialist be sure if a person has type I or type II DM based on the sub-acute presentation of the disease?(4 votes)
- A lot of type I DM patients are diagnosed when they present with their first episode of diabetic ketoacidosis (DKA). Generally type II DM is found by looking for it in patients with risk factors, or with a history that suggests DM might be a possibility. To some degree it's possible to differentiate with markers like C peptide (which is an inactive bit snipped off the end of the insulin molecule), but in advanced type II DM the islet cells can "burn out" from trying to compensate and insulin production can be lost.(3 votes)
- How does the Dawn effect happen?(2 votes)
- How ketoacidosis affect to diabetes?(1 vote)
- isn't there any disease which relates to loss of glutamate ?(1 vote)
- No but there is Parkinson's disease wich can cause a high level of glutamate and kill neurons that produce dopamine
hope I helped : )(1 vote)
- but 1 question How Do People get ebola im guessing Ebola River(1 vote)
- https://www.khanacademy.org/science/health-and-medicine/current-issues-in-health-and-medicine/ebola-outbreak/a/ebola-at-a-glance
https://www.cdc.gov/vhf/ebola/
Ebola is the common name given to a family of viruses that emerged in Africa. People typically acquire the virus from another person with the virus. There have been very few cases confirmed since 2014 and they have been in West Africa.There is no reason to guess when you have so much reliable, factual information available to you at Khan and elsewhere on the internet, such as the CDC, Center for Disease Control.(2 votes)
- Can a person have and exhale breath order that almost has a sweet smell to it(0 votes)
- Breath odor mostly has to do with the last thing you ate and how well you clean your moth and teeth. A persistent sweet/fruity smell can be because of diabetes and might be when the person has ketoacidosis, which is really dangerous. It's basically when there's no insulin so instead of using sugar for energy, the body starts using fat which causes ketones to build up; ketones in large amounts are poisonous and can cause serious damage to the body, even death.(1 vote)
Video transcript
- [Voiceover] Let's
discuss the presentation and diagnosis of diabetes mellitus. Recall that diabetes mellitus
is a group of disorders that can be caused by multiple different underlying mechanisms. However, all the different
types are diagnosed in the same way, and that is a combination of clinical presentation
and diagnostic tests. So let's erase this here and start with the presentation
of diabetes mellitus. Recall there are two types of diabetes, type I and type II, and
depending on the type the disease presentation will differ. And there are three main ways in which someone with diabetes will present before they're diagnosed with the disease, and they are acute,
subacute, and asymptomatic. Now let's start with
the acute presentation. This is the most severe
presenting situation and can be life threatening for both type I and type II diabetes. This individual becomes very sick over a relatively short period of time, usually only a couple of days. Now symptoms will include things like nausea, vomiting, and abdominal pain and this often results
in severe dehydration, and as such the individual
may even become confused or unconscious as a result. In type I diabetes, this is known as diabetic ketoacidosis, or DKA for short. And it is how about 30% of
individuals with type I diabetes will initially present before diagnosis. In type II diabetes,
the acute presentation has a much longer name. It's known as hyperosmolar
nonketotic state, or HHNS for short, and it's
much less common than DKA as it's the initial presentation for only about 2% of individuals
with type II diabetes. Now the difference between DKA and HHNS has to do with the difference
between the underlying mechanisms of type I diabetes
and type II diabetes. Now the most important
difference is that in DKA the individual will become acidotic due to the production of ketoacids, hence the name diabetic ketoacidosis as opposed to hyperosmolar
nonketotic state where ketoacids are not produced. Now the next way individuals with diabetes can present is what we'll call subacute. And this is a mild to
moderate presentation that occurs over a period
of weeks to months. And these individuals or
maybe someone close to them notice that they are
generally just not feeling as well as they normally
do and they may experience symptoms of fatigue, increased thirst, frequent urination, or even weight loss. Now, once again this can occur with either type I or type II diabetes. And in type I diabetes,
this is the most common form of presentation before diagnosis, accounting for about 70% of individuals with type I diabetes. In type II diabetes, this is also common, however the predominant symptoms are a little bit more vague
and weight loss is less common. Then the last way individuals
with diabetes can present is through asymptomatic screening tests. So type II diabetes affects
nearly 10% of the population, and due to this high
prevalence, potentially severe complications, and the
relative ease of treatment, most adults, especially
those with the risk factors of type II diabetes should be routinely screened for the disease. And this is the most common means by which type II diabetes is diagnosed. However, it's rare for the
diagnosis of type I diabetes as routine screening for type I diabetes is not usually performed. So let's move on to the diagnostic tests for diabetes mellitus Regardless of the type of
diabetes or the severity of presentation, laboratory
tests are necessary for the diagnosis of diabetes mellitus. So let's briefly review
the general mechanism of diabetes to gain a better understanding of the two major laboratory tests that are used to diagnose the disease. As the blood glucose
levels in the body rise, this is sensed by the
beta cells in the pancreas which secrete the hormone insulin. And insulin then acts on
cells throughout the body to take the glucose from the blood up and thus lower the blood glucose levels. So in diabetes mellitus,
regardless of the type, this insulin pathway is
not working properly, therefore the body is not able to lower blood glucose levels. And this results in increased
blood glucose levels known as hyperglycemia,
which is the characteristic finding of diabetes mellitus. Now a side effect of
hyperglycemia is a proccess known as glycosylation,
which is the non-enzymatic attachment of glucose to proteins. And one protein that this occurs with that is of importance in diabetes mellitus is the protein hemoglobin which is located within red blood cells. And in the presence of hyperglycemia, glucose will attach
itself to an abnormally high percentage of hemoglobin
within the red blood cells. And this is known as
glycosylated hemoglobin, or hemoglobin A1C, and
it's the hyperglycemia and the hemoglobin A1C that
are tested for in the blood to aid in the diagnosis
of diabetes mellitus. So let's put this diagram
over here to the side and discuss a little bit more
about these diagnostic tests. First, let's talk about
the three categories of results for the diagnostic tests. And the first is a normal level. The second is the level that's
associated with diabetes. And then in between is a third category, and it relates only to type II diabetes, and it's known as pre-diabetes. Since type II diabetes
is a chronic disease that typically takes many years to develop and it's routinely
screened for, often times individuals will have
a test result that is above the normal level
however not severe enough to be considered diabetes and
this is known as pre-diabetes. And it's important because
individuals with pre-diabetes, as it's name suggests,
are much more likely to develop type II diabetes in the future. So by identifying them
as having pre-diabetes, they can start treating
the underlying mechanism through lifestyle modifications
such as weight loss, proper diet, and routine
exercise in order to prevent or delay the development of
type II diabetes in the future. Now, as we mentioned before,
there are two major types of laboratory tests used to
diagnose diabetes mellitus, and they are blood glucose
levels and hemoglobin A1C. The blood glucose level can be measured by many different methods
and, unfortunately, depending on the method
the results will vary. So the three most common methods are random, fasting, and a
two-hour glucose tolerance test which we'll just abbreviate GTT. Now we'll bring in the the
different diagnostic levels here, however the exact numbers
for each of these categories are less important than
a couple of trends. And the first one is that
regardless of the method: random, fasting, or the
two-hour glucose tolerance test, a blood glucose level of greater
than or equal to 200 mg/dL is consistent with diabetes. But this number is slightly lower if fasting blood glucose levels is used. Then the level is 126 mg/dL. Then the last important point to mention is that a random glucose
test can not be used to diagnose pre-diabetes. You need either a fasting or a two-hour glucose tolerance test. Now, fortunately hemoglobin A1C testing is a little bit more straight forward, as the timing of the test does not matter. And then similarly to
the blood glucose test, there's one important number to remember. And that is that a level
greater than or equal to 6.5% is consistent with diabetes mellitus. So now that we have a better understanding of the clinical presentation
of diabetes mellitus and the laboratory tests, let's
bring these two components together to discuss how the diagnosis of diabetes mellitus is made. Neither the presentation or
the diagnostic tests alone is enough to diagnose diabetes. The diagnosis is made by
a combination of the two. And there are two ways diabetes
mellitus can be diagnosed, and they're based on
different presentations. So first, if an individual
has symptoms of diabetes, whether acute or subacute,
then only one positive test, either the blood glucose
or the hemoglobin A1C is necessary for the diagnosis
of diabetes mellitus. However, if the individual
is asymptomatic, then a diagnosis of
diabetes mellitus requires two positive tests that are separated by at least one week of time.