Respiratory Tract Infections: Classification

by Jeremy Brown, PhD

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    00:00 When we're talking about lung infections, we define the infection by the site.

    00:05 So that means that if you have an infection of the pharynx, or the nose, or the larynx, that's called an upper respiratory tract infection.

    00:13 And that's usually the common cold or viral infection that we've all had repeatedly in our lives.

    00:18 There are the occasional rare diseases caused by bacteria, which we'll mention later diphtheria / epiglottitis, for example.

    00:25 Then in the lower respiratory tract, you may get infections, which only affect the trachea, or the bronchial tree.

    00:32 Now, they tend to be that you will get an infection of the trachea and it will spread to the bronchi.

    00:37 They're not independent of each other.

    00:39 Usually you get a tracheobronchitis.

    00:42 And again, that's often a viral infection.

    00:44 And again, we've probably all had those several times in our lives.

    00:48 That's the acute infection of the bronchial tree.

    00:51 Chronic bronchial infection is largely a disease called bronchiectasis.

    00:55 And that's a subject I wanted to talks on airways disease.

    00:59 The main subject of this lecture is pneumonia.

    01:02 And that is an infection that's affecting the alveoli.

    01:06 And it's an acute infection.

    01:09 There are a range of less acute infections of the alveoli.

    01:13 Tuberculosis being the most common.

    01:15 Other things will be lung abscess, and some very rare infections due to fungi and unusual bacteria.

    01:21 And those are mentioned and discussed in the talk in tuberculosis.

    01:26 So today, we really concentrate on acute pneumonia alveolar infection, and it could be due to a virus, or it could be due to bacteria.

    01:35 So, pneumonia is incredibly common.

    01:38 It affects about one in 200 people each year and it is actually the commonest cause of death in children under the age of five across the developing world.

    01:46 As I've already mentioned, the pneumococcus streptococcus pneumoniae is the commonest cause.

    01:53 Before we discussed pneumonia, I'm just briefly going to cover upper respiratory tract infections.

    01:59 These are incredibly common.

    02:00 As I've mentioned, we all have had colds in our life and will get repeated colds as time goes by.

    02:05 These are mainly due to viruses. Rhinovirus, Adenovirus various influenza viruses, Metapneumovirus, etc.

    02:12 And occasionally they can be due to a bacterium the common is been streptococcus pyogenes, which causes the disease, that everyone calls strep throat.

    02:19 And that's basically a bacterial infection of the pharynx.

    02:22 Patients with upper respiratory tract infections presents similarly an independent of what the pathogen is was sneezing, a sore throat, cough, mild systemic upset, a bit of a fever, feeling unwell, wanting to go to bed.

    02:35 And the treatment actually is not much.

    02:37 We just leave this, and people will get better most of the time.

    02:41 If you have a strep pyogenes pharyngitis then actually antibiotics would be helpful, and penicillin will be beneficial in those circumstances.

    02:50 There are a couple of bacterial infection the upper respiratory tract which are very important because they are potentially dangerous.

    02:57 Diptheria is a laryngitis.

    02:59 An infection of the larynx caused by a bacterium called Corynebacterium diphtheriae.

    03:04 The important thing about diphtheria is that the infection forms what we call a pseudomembrane.

    03:09 As an extra layer of gunky tissue on the surface of the larynx, And that pseudomembrane causes obstruction of the larynx.

    03:18 And of course, the larynx is a relatively small surface area, and is where all the air that goes into your lungs has to pass through.

    03:24 And that causes airways obstruction, and therefore is potentially dangerous, and which is why diphtheria used to be a very common cause of death in infants.

    03:34 Epiglottitis is a rare infection of the epiglottis, as his name suggests, and that's due to a bacteria called haemophilus influenzae.

    03:42 And again, it causes swelling of the epiglottis and therefore cause upper airways obstruction and is potentially dangerous as a consequence of that.

    03:49 Fortunately, diphtheria can be vaccinated against and has become much less of a problem than it used to be in the past.

    03:57 So, if we talk about lower respiratory tract infections, those that occur below the larynx, affecting the trachea, the bronchi, or the alveoli.

    04:04 In fact, most patients lower speech transfection will have the tracheobronchitis that we mentioned.

    04:09 That's the bottom part of this pyramid of infection.

    04:11 And only a small portion of patients actually go on to divert the more serious form of lower respiratory tract infection, which is the pneumonia.

    04:19 And of those with pneumonia, say about 100 people pneumonia, about 70% can be treated successfully in the community.

    04:26 You don't need to get into hospital if you have pneumonia, because most cases is relatively mild.

    04:31 However, in some people is a more severe disease.

    04:34 And in some people is very severe disease, and they end up in hospital potentially in intensive care.

    04:39 And there is a mortality which probably overall for each 100 people pneumonia, about three will die.

    About the Lecture

    The lecture Respiratory Tract Infections: Classification by Jeremy Brown, PhD is from the course Infections of the Respiratory Tract.

    Included Quiz Questions

    1. Herpes simplex virus
    2. Influenza A
    3. Mycobacterium tuberculosis
    4. Streptococcus pneumoniae
    1. Pneumonia
    2. Tuberculosis
    3. Lung cancer
    4. Asthma
    5. Lung abscess
    1. Pneumonia
    2. Tuberculosis
    3. Lung cancer
    4. Asthma
    5. Lung abscess
    1. Haemophilus influenzae
    2. Klebsiella pneumoniae
    3. Streptococcus pyogenes
    4. Moraxella catarrhalis
    5. Corynebacterium diphtheriae
    1. Diphtheria was a very rare cause of death in infants until recently.
    2. Diphtheria causes pseudomembrane formation.
    3. Diphtheria can cause obstruction of the larynx.
    4. Diphtheria is mostly seen in children.
    5. Diphtheria can be prevented with vaccination.

    Author of lecture Respiratory Tract Infections: Classification

     Jeremy Brown, PhD

    Jeremy Brown, PhD

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    By Luz angela B. on 22. March 2021 for Respiratory Tract Infections: Classification

    fue una conferencia muy clara,organizada,los medios que utilizaron para realizar las presentaciones fueron muy enteractivos ,muy claros, buena iluminacion. por lo tanto me ayudo a enteder el tema, me parecio que los subtitulos iban muy rapido y se me dificulta mucho porque hablo solo español.