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Flu Symptoms and Diagnosis
Learn the common symptoms of the flu and how it can be diagnosed.
These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video. Created by Stanford School of Medicine.
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- What is the difference between cold and flu?(8 votes)
- the flu is worse than the common cold, and symptoms such as fever, body aches, extreme tiredness, and dry cough are more common and intense.Colds are usually milder than the flu. People with colds are more likely to have a runny or stuffy nose.(7 votes)
- If it gets spread how did the first person who got the virus get the Influenza virus.(6 votes)
- Do you mean the first person ever to get the influenza virus? Or just the first person in the chain of infection that gets the influenza virus.(1 vote)
- At about2:36it is said that influenza shows either sore throat or cough along with a fever as symptoms ?
Is there any specific reason why the influenza only causes either of the symptoms unlike some other problems like the Common Cold ?(4 votes)- That was one area that confused me, but after looking into more, I discovered that the influenza is actually much more specific than the common cold. While the cold can cause a variety of symptoms, the virus that leads to influenza is more detailed in how, and what, it affects, and thus leads to very specific symptoms. The particular viruses that cause influenza seems to affect only one symptom - this virus only cause influenza with a sore throat, while this one causes influenza with a cough. These differences between the common cold and actual influenza are major way by which one can determine whether their sickness is one or the other.(4 votes)
- @2:01- Why one experiences chill during influenza?(4 votes)
- Wikipedia: Chills is a feeling of coldness occurring during a high fever. It occurs during fever due to the release of cytokines and prostaglandins as part of the inflammatory response, which increases the set point for body temperature in the hypothalamus.[citation needed] The increased set point causes the body temperature to rise (pyrexia), but also makes the patient feel cold or chills until the new set point is reached. Shivering also occurs along with chills because the patient's body produces heat during muscle contraction in a physiological attempt to increase body temperature to the new set point.(3 votes)
- What would be considered an extreme fever in temperature? By extreme, I mean the temperature is so high you could be admitted into like the ER or something of that sort. During the 2012-2013 school year, I had a fever that reached 40 degrees Celsius, which is 104 degrees Fahrenheit and it stayed like that for an hour. The doctors said it was a 'mild fever' and I was like 'yeah sure, like you get patients with temperatures over 104.' in my mind(3 votes)
- Medically, it's mild. A fever is considered to be extreme once it goes above 104 degrees Farenheit. Plus, fever severity is measured in both temperature and duration, and if you went in after your fever was over, then your doctor was right when he said that the fever was mild.(2 votes)
- when you have the flu or a cold does it mess up or slow down your brain?(2 votes)
- Your brain uses 20% of the calories you body has stored. Now these calories are being devoted to healing you, which means the brain can't operate at maximum efficiency. Also, if you have the flu, you probably aren't sleeping well due to a runny nose and coughing, and sleep deprivation screws up your brain to a huge extent.(4 votes)
- Are there any viruses that can insert themselves into your skin? Is it possible influenza can mutate this ability?
(I'm going to get nightmares...)(2 votes)- Don't worry, viruses can only come in through sensitive openings (mouth, ears, eyes, nose, etc,) and even those places are guarded. Viruses can only come through the skin if there is a cut- and your immune system will most likely get rid of it anyways :)(3 votes)
- Would it be possible to lab confirm an influenza case though the use of a sample of blood and blood analysis?(1 vote)
- Definitely, yes, but it's too slow, expensive, and impractical to be of much clinical use for flu-like viruses.(3 votes)
- What is a viruse? Im so scared of them:((1 vote)
- viruses are particles that can reproduce by using the cells of their hosts.
https://www.khanacademy.org/science/biology/tree-of-life/v/viruses(2 votes)
- I always thought that the flu caused you to through up... is that not the case? these symptoms that are described in this video seem to be what I've always thought of as a cold.(1 vote)
- It is not common to throw up. However, if enough mucus is ingested into the stomach, then sometimes you do vomit. But this is just a reaction to unpleasant material in the stomach; it is not a symptom of the flu virus.(2 votes)
Video transcript
Female Voiceover: At this point
in your life, you've probably been
infected with the influenza virus. So think back, if you can, on what was
probably a pretty miserable experience. Think of the symptoms that you had. All the symptoms that we feel
when we're sick with the flu
are related to the course that the virus takes as
it moves through our body. But first the virus has
to get into our body. Let's say that someone who is infected
with the flu sneezes or coughs near you and they spray a bunch of
tiny droplets into the air. Each of these droplets can contain
millions of influenza viruses. And if we breathe this in
through the nose or the mouth,
we can get infected this way. Another way we can get infected
is, let's say some of these
droplets settle on a surface like a table for instance. The flu virus can survive on a surface
like this for two to eight hours. So if we're unfortunate enough
to touch a surface like this and
then touch our mouth or our nose we can get infected this way as well. This is why practicing good
hand hygiene is so critical in
preventing the spread of disease. So don't forget to wash your hands,
especially during flu season. Now in this case, unfortunately the
virus has entered into our system. It's moving its way through our body. It's going to infect cells along
the way and cause cell damage. The damage that these cells experience
is going to show up as the symptoms
that we're so familiar with. As the virus moves in through the
nose, we might get some congestion. Then the virus is going to
make its way down into the
throat, giving us a sore throat. Then it will get all the way
into the lungs causing a cough. In response to the damage that
the virus causes the body, the immune system is going to
increase the temperature of the body in hopes that this will make
viral replication more difficult. This is why we get fever and chills. This battle that the body is fighting
against, the influenza virus, consumes a lot of energy. This is why we are so exhausted when
all of a sudden we're in bed for days. It's miserable. A lot of common viruses can
cause these symptoms, right? The common cold, for instance,
can give us a runny nose. So how do we know that it's actually
the influenza virus specifically that is making us feel so sick? Typically a person infected
with influenza virus will have
a fever of over 100 degrees, along with either a
sore throat or a cough. This combination of symptoms is what
we call an influenza-like illness. We say influenza-like illness because it's
not yet confirmed with a laboratory test. It's just a combination of symptoms. We shorten this by saying ILI. During flu season between
December and February, doctors who see an influenza-like
illness will usually attribute
this to an infection with the influenza virus without
getting a laboratory test. So next time your friend says, "I had the flu last week. I
was completely congested." Now you know you can say, "Well did you have a fever with
either a sore throat or a cough?" Because that is what you really
need for the clinical diagnosis
of an influenza-like illness. Some doctors actually might
want to confirm their diagnosis
of influenza with a lab test. They do this by using something that
looks kind of like a giant Q-Tip. They go straight to the source. Let's think about the places that you'd
most likely find an influenza virus in someone who is sick. You'd go to the nose and
you'd go to the throat right? Remember this is why we have nasal
congestion and a sore throat, because the virus is hanging out here. We call this a nasopharyngeal swab. Naso for nose and pharyngeal for throat. We're going to take
this nasopharyngeal swab into the nose, into the back of the
throat, to collect some of these cells. We're going to send this to the
lab to find out if in fact it's
an infection with influenza virus. There are other kinds of lab
tests that can confirm the
diagnosis of influenza infection but this is the most common
and most likely what you'll
see in a clinical setting.