[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:05.54,0:00:07.67,Default,,0000,0000,0000,,Male Voiceover: I wanted to\Ntalk to about the Mantoux test.
Dialogue: 0,0:00:07.67,0:00:11.92,Default,,0000,0000,0000,,This is spelled Mantoux, kind\Nof an interesting spelling.
Dialogue: 0,0:00:11.92,0:00:14.58,Default,,0000,0000,0000,,after a French doctor who popularized it.
Dialogue: 0,0:00:14.58,0:00:19.36,Default,,0000,0000,0000,,And another way you might hear\Nthis referred to is a PPD or a TST.
Dialogue: 0,0:00:19.36,0:00:21.38,Default,,0000,0000,0000,,And what these things stand for is
Dialogue: 0,0:00:21.38,0:00:25.98,Default,,0000,0000,0000,,PPD stands for Purified\NProtein Derivative,
Dialogue: 0,0:00:25.98,0:00:30.10,Default,,0000,0000,0000,,and actually gives us a clue as\Nto what we're using in this test,
Dialogue: 0,0:00:30.10,0:00:34.79,Default,,0000,0000,0000,,which is that we're using specifically\NTB protein. I'll put that in parenthesis.
Dialogue: 0,0:00:34.79,0:00:42.46,Default,,0000,0000,0000,,and the location of the test\Nis actually also going to be\Nkind of a clue here with TST.
Dialogue: 0,0:00:42.46,0:00:45.14,Default,,0000,0000,0000,,This is a tuberculin. Again,\Nreferring to tuberculosis.
Dialogue: 0,0:00:45.14,0:00:48.13,Default,,0000,0000,0000,,Tuberculin Skin Test.
Dialogue: 0,0:00:48.13,0:00:50.62,Default,,0000,0000,0000,,This tells you where we're\Ngoing to put all that protein.
Dialogue: 0,0:00:50.62,0:00:52.17,Default,,0000,0000,0000,,We're going to put it in the skin.
Dialogue: 0,0:00:52.17,0:00:56.09,Default,,0000,0000,0000,,You may have seen this, and\Nthis is a picture right here\Nof someone doing the test.
Dialogue: 0,0:00:56.09,0:00:59.37,Default,,0000,0000,0000,,Sometimes it's referred\Nto as the bubble test.
Dialogue: 0,0:00:59.37,0:01:02.09,Default,,0000,0000,0000,,A lot of people say, "Oh\Nyeah, my doctor injected
Dialogue: 0,0:01:02.09,0:01:05.20,Default,,0000,0000,0000,,"some liquid in my forearm\Nand it bubbled up."
Dialogue: 0,0:01:05.20,0:01:07.81,Default,,0000,0000,0000,,This is how people usually\Nthink about this test.
Dialogue: 0,0:01:07.81,0:01:11.14,Default,,0000,0000,0000,,They remember that because\Nof a very obvious visual.
Dialogue: 0,0:01:11.14,0:01:13.55,Default,,0000,0000,0000,,And so what I wanted to\Ndo was give you an example
Dialogue: 0,0:01:13.55,0:01:17.42,Default,,0000,0000,0000,,or a diagram of what's actually\Nhappening when you get this test done.
Dialogue: 0,0:01:17.42,0:01:20.16,Default,,0000,0000,0000,,Let's imagine this is your skin layer.
Dialogue: 0,0:01:20.16,0:01:22.35,Default,,0000,0000,0000,,This is also referred to as the dermis.
Dialogue: 0,0:01:22.35,0:01:26.48,Default,,0000,0000,0000,,Below the dermis is some subcutaneous.
Dialogue: 0,0:01:26.48,0:01:30.64,Default,,0000,0000,0000,,Below the skin, subcutaneous layer.
Dialogue: 0,0:01:30.64,0:01:33.62,Default,,0000,0000,0000,,Usually not layer. One of the\Nmost common things is fat.
Dialogue: 0,0:01:33.62,0:01:36.15,Default,,0000,0000,0000,,I'm just going to draw that in here.
Dialogue: 0,0:01:36.15,0:01:37.66,Default,,0000,0000,0000,,This is the subcutaneous fat.
Dialogue: 0,0:01:37.66,0:01:40.48,Default,,0000,0000,0000,,So the idea here is that you're basically\Nputting a little needle in here,
Dialogue: 0,0:01:40.48,0:01:42.88,Default,,0000,0000,0000,,which is what you're seeing in\Nthat picture on the right there.
Dialogue: 0,0:01:42.88,0:01:47.39,Default,,0000,0000,0000,,That needle is full of some TB protein.
Dialogue: 0,0:01:47.39,0:01:50.73,Default,,0000,0000,0000,,So this Purified Protein\NDerivative is in that needle.
Dialogue: 0,0:01:50.73,0:01:52.38,Default,,0000,0000,0000,,It's actually going to be injected in.
Dialogue: 0,0:01:52.38,0:01:54.47,Default,,0000,0000,0000,,So you've got all these\Nlittle TB proteins in here.
Dialogue: 0,0:01:54.47,0:01:57.63,Default,,0000,0000,0000,,And the volume you're\Nputting in is a small volume.
Dialogue: 0,0:01:57.63,0:01:59.85,Default,,0000,0000,0000,,It's about one-tenth of a milliliter.
Dialogue: 0,0:01:59.85,0:02:04.23,Default,,0000,0000,0000,,So 0.1 mL and you're\Nputting it intradermally.
Dialogue: 0,0:02:04.23,0:02:06.26,Default,,0000,0000,0000,,This is actually an important point.
Dialogue: 0,0:02:06.26,0:02:08.24,Default,,0000,0000,0000,,It's going into that dermis layer.
Dialogue: 0,0:02:08.24,0:02:10.81,Default,,0000,0000,0000,,So it's intradermal injection.
Dialogue: 0,0:02:10.81,0:02:13.53,Default,,0000,0000,0000,,What happens is that if you\Nthen let's say moments later
Dialogue: 0,0:02:13.53,0:02:15.79,Default,,0000,0000,0000,,you remove the needle, you throw it away.
Dialogue: 0,0:02:15.79,0:02:18.49,Default,,0000,0000,0000,,And now what you're going\Nto notice is because
Dialogue: 0,0:02:18.49,0:02:21.94,Default,,0000,0000,0000,,you put a little volume\Nin there, a little 0.1 mL,
Dialogue: 0,0:02:21.94,0:02:24.20,Default,,0000,0000,0000,,that is going to bubble\Nup because that volume
Dialogue: 0,0:02:24.20,0:02:27.16,Default,,0000,0000,0000,,is going to make the skin\Npuff out a little bit.
Dialogue: 0,0:02:27.16,0:02:31.55,Default,,0000,0000,0000,,But if I came back over some time,\Nthis protein is diffused over,
Dialogue: 0,0:02:31.55,0:02:34.06,Default,,0000,0000,0000,,this liquid has been\Nabsorbed into the skin,
Dialogue: 0,0:02:34.06,0:02:36.00,Default,,0000,0000,0000,,and that bubble will disappear.
Dialogue: 0,0:02:36.00,0:02:38.45,Default,,0000,0000,0000,,If you come back, you might\Nsee a little bit of redness,
Dialogue: 0,0:02:38.45,0:02:42.61,Default,,0000,0000,0000,,because of course poking the skin causes\Na little bit of redness and irritation.
Dialogue: 0,0:02:42.61,0:02:45.06,Default,,0000,0000,0000,,But the bubble will disappear over time.
Dialogue: 0,0:02:45.06,0:02:47.74,Default,,0000,0000,0000,,So what are we hoping to\Naccomplish with this test exactly?
Dialogue: 0,0:02:47.74,0:02:50.42,Default,,0000,0000,0000,,Let me bring up a couple\Nof more pictures for us.
Dialogue: 0,0:02:50.42,0:02:53.09,Default,,0000,0000,0000,,Well this test is going to\Nhelp us answer the question
Dialogue: 0,0:02:53.09,0:02:58.79,Default,,0000,0000,0000,,of has the person had prior TB exposure?
Dialogue: 0,0:02:58.79,0:03:00.16,Default,,0000,0000,0000,,Just remember that.
Dialogue: 0,0:03:00.16,0:03:01.93,Default,,0000,0000,0000,,That's the question\Nwe're trying to answer.
Dialogue: 0,0:03:01.93,0:03:04.99,Default,,0000,0000,0000,,Have they had prior TB\Nexposure? Yes or no.
Dialogue: 0,0:03:04.99,0:03:07.46,Default,,0000,0000,0000,,Let's think about what would\Nhappen in either scenario.
Dialogue: 0,0:03:07.46,0:03:10.77,Default,,0000,0000,0000,,So this would be that they\Nhave not had prior TB exposure.
Dialogue: 0,0:03:10.77,0:03:16.88,Default,,0000,0000,0000,,And on this side let's talk\Nabout what would happen if they\Nhave had prior TB exposure.
Dialogue: 0,0:03:16.88,0:03:20.53,Default,,0000,0000,0000,,So two scenarios. Let's\Nstart on the no side.
Dialogue: 0,0:03:20.53,0:03:22.34,Default,,0000,0000,0000,,Let's draw our skin again.
Dialogue: 0,0:03:22.34,0:03:23.64,Default,,0000,0000,0000,,So this is just as before.
Dialogue: 0,0:03:23.64,0:03:25.73,Default,,0000,0000,0000,,Let's draw some TB protein in here.
Dialogue: 0,0:03:25.73,0:03:29.18,Default,,0000,0000,0000,,What's going to happen is you're\Ngoing to have some macrophages.
Dialogue: 0,0:03:29.18,0:03:31.15,Default,,0000,0000,0000,,These macrophages are going to come around
Dialogue: 0,0:03:31.15,0:03:33.49,Default,,0000,0000,0000,,and they're always patrolling the area.
Dialogue: 0,0:03:33.49,0:03:35.61,Default,,0000,0000,0000,,They're making sure\Nthat almost like police
Dialogue: 0,0:03:35.61,0:03:37.82,Default,,0000,0000,0000,,officers making sure\Nthat there's no problem.
Dialogue: 0,0:03:37.82,0:03:40.03,Default,,0000,0000,0000,,They're going to come\Nand they're going to pick
Dialogue: 0,0:03:40.03,0:03:41.38,Default,,0000,0000,0000,,up some of this TB protein.
Dialogue: 0,0:03:41.38,0:03:43.22,Default,,0000,0000,0000,,So they're going to take\Nit inside of themselves.
Dialogue: 0,0:03:43.22,0:03:47.07,Default,,0000,0000,0000,,They're going to present that\NTB protein to another cell.
Dialogue: 0,0:03:47.07,0:03:49.19,Default,,0000,0000,0000,,This is our T-cell.
Dialogue: 0,0:03:49.19,0:03:52.11,Default,,0000,0000,0000,,They're going to present this\NTB protein to the T-cell.
Dialogue: 0,0:03:52.11,0:03:54.28,Default,,0000,0000,0000,,The T-cell is going to\Nsay, "You know, I have had
Dialogue: 0,0:03:54.28,0:03:58.12,Default,,0000,0000,0000,,"no prior TB exposure. I don't\Nrecognize this TB protein.
Dialogue: 0,0:03:58.12,0:04:01.49,Default,,0000,0000,0000,,and it's going to go on its merry way.
Dialogue: 0,0:04:01.49,0:04:03.71,Default,,0000,0000,0000,,It's not going to make a big\Ndeal about what's going on.
Dialogue: 0,0:04:03.71,0:04:05.69,Default,,0000,0000,0000,,So the T-cell kind of meanders away.
Dialogue: 0,0:04:05.69,0:04:09.11,Default,,0000,0000,0000,,It leaves the area. It\Nleaves proteins over time.
Dialogue: 0,0:04:09.11,0:04:12.12,Default,,0000,0000,0000,,It starts to get chewed up\Nand digested by macrophages.
Dialogue: 0,0:04:12.12,0:04:14.72,Default,,0000,0000,0000,,Eventually all of it is gone.
Dialogue: 0,0:04:14.72,0:04:18.86,Default,,0000,0000,0000,,If you look on the\Noutside you see flatness.
Dialogue: 0,0:04:18.86,0:04:20.76,Default,,0000,0000,0000,,The skin looks nice and flat.
Dialogue: 0,0:04:20.76,0:04:22.94,Default,,0000,0000,0000,,This might seem very\Nobvious from this picture.
Dialogue: 0,0:04:22.94,0:04:24.83,Default,,0000,0000,0000,,Of course it looks flat\Nbut that's essentially what
Dialogue: 0,0:04:24.83,0:04:27.04,Default,,0000,0000,0000,,we're looking at here is flatness.
Dialogue: 0,0:04:27.04,0:04:29.85,Default,,0000,0000,0000,,Looking at this picture, you can\Nsee a little bit of redness here.
Dialogue: 0,0:04:29.85,0:04:33.02,Default,,0000,0000,0000,,If you were to feel it with\Nyour finger, it would be flat.
Dialogue: 0,0:04:33.02,0:04:35.71,Default,,0000,0000,0000,,So it's red but it's flat.
Dialogue: 0,0:04:35.71,0:04:36.98,Default,,0000,0000,0000,,And that's the key.
Dialogue: 0,0:04:36.98,0:04:41.09,Default,,0000,0000,0000,,In this person we would say\Nif there is no bulge or bump,
Dialogue: 0,0:04:41.09,0:04:44.86,Default,,0000,0000,0000,,we would say this person\Nhas a negative PPD.
Dialogue: 0,0:04:44.86,0:04:47.00,Default,,0000,0000,0000,,This person right here has a negative PPD.
Dialogue: 0,0:04:47.00,0:04:52.27,Default,,0000,0000,0000,,So that's basically how we\Nwould read this flat PPD.
Dialogue: 0,0:04:52.27,0:04:54.08,Default,,0000,0000,0000,,Now what happens on the yes side.
Dialogue: 0,0:04:54.08,0:04:56.66,Default,,0000,0000,0000,,Let's say the person has\Nhad prior TB exposure.
Dialogue: 0,0:04:56.66,0:04:58.58,Default,,0000,0000,0000,,So the same setup as before.
Dialogue: 0,0:04:58.58,0:05:00.14,Default,,0000,0000,0000,,Let's draw the skin.
Dialogue: 0,0:05:00.14,0:05:01.54,Default,,0000,0000,0000,,There we've got some TB protein.
Dialogue: 0,0:05:01.54,0:05:04.08,Default,,0000,0000,0000,,Let me draw that in here.
Dialogue: 0,0:05:04.08,0:05:06.82,Default,,0000,0000,0000,,And this TB protein is\Ngoing to get picked up
Dialogue: 0,0:05:06.82,0:05:09.12,Default,,0000,0000,0000,,as before by the macrophage.
Dialogue: 0,0:05:09.12,0:05:12.95,Default,,0000,0000,0000,,The macrophage is going to come by\Nand pick up some of this TB protein.
Dialogue: 0,0:05:12.95,0:05:16.37,Default,,0000,0000,0000,,And just as before it's\Ngoing to find a T-cell.
Dialogue: 0,0:05:16.37,0:05:20.09,Default,,0000,0000,0000,,These T-cells are also\Nkind of moving around.
Dialogue: 0,0:05:20.09,0:05:22.89,Default,,0000,0000,0000,,This T-cell this time is going to say,
Dialogue: 0,0:05:22.89,0:05:26.16,Default,,0000,0000,0000,,"You know what? I have seen\Nthis TB protein before."
Dialogue: 0,0:05:26.16,0:05:30.14,Default,,0000,0000,0000,,And this T-cell is going to\Nstart getting very excited.
Dialogue: 0,0:05:30.14,0:05:31.61,Default,,0000,0000,0000,,And this is the key difference,\Nright? It's going to get excited.
Dialogue: 0,0:05:31.61,0:05:33.50,Default,,0000,0000,0000,,Before it didn't get excited.
Dialogue: 0,0:05:33.50,0:05:35.45,Default,,0000,0000,0000,,It just left the area unexcited.
Dialogue: 0,0:05:35.45,0:05:41.96,Default,,0000,0000,0000,,Now it gets excited and it\Nstarts releasing chemokines,\Nlittle chemical messages.
Dialogue: 0,0:05:41.96,0:05:44.03,Default,,0000,0000,0000,,You know what that does?
Dialogue: 0,0:05:44.03,0:05:47.82,Default,,0000,0000,0000,,That attracts lots and lots\Nof other cells to the area.
Dialogue: 0,0:05:47.82,0:05:49.62,Default,,0000,0000,0000,,Lots of macrophages\Nstart coming to the area.
Dialogue: 0,0:05:49.62,0:05:51.53,Default,,0000,0000,0000,,They say, "Aha, interesting."
Dialogue: 0,0:05:51.53,0:05:54.19,Default,,0000,0000,0000,,The T-cell tells us that\Nwe've seen this stuff before,
Dialogue: 0,0:05:54.19,0:05:57.22,Default,,0000,0000,0000,,and this layer, this intradermal layer,
Dialogue: 0,0:05:57.22,0:05:59.89,Default,,0000,0000,0000,,starts to swell up with cells.
Dialogue: 0,0:05:59.89,0:06:02.85,Default,,0000,0000,0000,,So it's getting full\Nof cells because of all
Dialogue: 0,0:06:02.85,0:06:06.64,Default,,0000,0000,0000,,these new macrophages that are\Nbeing attracted to the area.
Dialogue: 0,0:06:06.64,0:06:08.35,Default,,0000,0000,0000,,So it's actually going to\Nstart looking like this.
Dialogue: 0,0:06:08.35,0:06:12.26,Default,,0000,0000,0000,,Full of cells, right, on both sides.
Dialogue: 0,0:06:12.26,0:06:17.39,Default,,0000,0000,0000,,It becomes a nice big bulge\Nand this is loaded with cells.
Dialogue: 0,0:06:17.39,0:06:20.60,Default,,0000,0000,0000,,Macrophages in here. Maybe a few\Nmore T-cells in here as well.
Dialogue: 0,0:06:20.60,0:06:22.84,Default,,0000,0000,0000,,You get the idea. Lots and lots of cells.
Dialogue: 0,0:06:22.84,0:06:26.60,Default,,0000,0000,0000,,We call this a hypersensitivity reaction.
Dialogue: 0,0:06:26.60,0:06:30.26,Default,,0000,0000,0000,,When you see all these\Ncells coming into this area,
Dialogue: 0,0:06:30.26,0:06:35.31,Default,,0000,0000,0000,,this is a classic\Nhypersensitivity reaction.
Dialogue: 0,0:06:35.31,0:06:37.82,Default,,0000,0000,0000,,In fact, there are different types\Nof hypersensitivity reactions.
Dialogue: 0,0:06:37.82,0:06:42.23,Default,,0000,0000,0000,,We would call this a class 4, type 4.
Dialogue: 0,0:06:42.23,0:06:44.84,Default,,0000,0000,0000,,The reason that they are\Ntyped out differently
Dialogue: 0,0:06:44.84,0:06:49.27,Default,,0000,0000,0000,,is that type 4 in particular\Ninvolves lots of cells.
Dialogue: 0,0:06:49.27,0:06:54.24,Default,,0000,0000,0000,,So this is a very cellular\Nreaction meaning lots of your\Nimmune cells are involved.
Dialogue: 0,0:06:54.24,0:06:55.69,Default,,0000,0000,0000,,You can see that in the drawing.
Dialogue: 0,0:06:55.69,0:06:58.14,Default,,0000,0000,0000,,You can see lots of macrophages\Nand T-cells in that area.
Dialogue: 0,0:06:58.14,0:07:01.67,Default,,0000,0000,0000,,So this is a type 4 hypersensitivity\Nreaction happening here.
Dialogue: 0,0:07:01.67,0:07:05.73,Default,,0000,0000,0000,,And if you were to feel with\Nyour finger from here to here,
Dialogue: 0,0:07:05.73,0:07:07.91,Default,,0000,0000,0000,,it would not feel flat, right?
Dialogue: 0,0:07:07.91,0:07:10.30,Default,,0000,0000,0000,,This is not flat at all.\NThis is actually bulging out.
Dialogue: 0,0:07:10.30,0:07:14.30,Default,,0000,0000,0000,,We call this indurated.\NMeaning it feels very firm.
Dialogue: 0,0:07:14.30,0:07:16.65,Default,,0000,0000,0000,,It does not feel flat.
Dialogue: 0,0:07:16.65,0:07:19.59,Default,,0000,0000,0000,,This is what you're seeing\Nin the picture here.
Dialogue: 0,0:07:19.59,0:07:25.14,Default,,0000,0000,0000,,You actually can see from here\Nto here there is induration.
Dialogue: 0,0:07:25.14,0:07:27.30,Default,,0000,0000,0000,,They're actually\Nmeasuring it with a ruler.
Dialogue: 0,0:07:27.30,0:07:29.05,Default,,0000,0000,0000,,So this is the induration.
Dialogue: 0,0:07:29.05,0:07:34.72,Default,,0000,0000,0000,,You can also see that they're doing\Nit perpendicular to the long axis.
Dialogue: 0,0:07:34.72,0:07:38.16,Default,,0000,0000,0000,,So in other words, if this\Nis the long axis this way,
Dialogue: 0,0:07:38.16,0:07:40.44,Default,,0000,0000,0000,,they are kind of choosing\Na 90 degree angle to that,
Dialogue: 0,0:07:40.44,0:07:43.22,Default,,0000,0000,0000,,something like that, to\Nmeasure the induration.
Dialogue: 0,0:07:43.22,0:07:46.16,Default,,0000,0000,0000,,So that's how you would\Nmeasure induration of a PPD.
Dialogue: 0,0:07:46.16,0:07:50.50,Default,,0000,0000,0000,,So this looks like a positive PPD\Non this second picture over here.
Dialogue: 0,0:07:50.50,0:07:53.68,Default,,0000,0000,0000,,We'll get into in just a\Nmoment how we actually decide
Dialogue: 0,0:07:53.68,0:07:55.12,Default,,0000,0000,0000,,if it's negative or positive.
Dialogue: 0,0:07:55.12,0:07:58.38,Default,,0000,0000,0000,,Now one thing I forgot to mention is\Nyou're going to be reading these PPDs
Dialogue: 0,0:07:58.38,0:08:04.42,Default,,0000,0000,0000,,48 to 72 hours after you\Ninitially injected the protein.
Dialogue: 0,0:08:04.42,0:08:07.72,Default,,0000,0000,0000,,So 48 to 72 hours later.
Dialogue: 0,0:08:07.72,0:08:09.69,Default,,0000,0000,0000,,This is when you actually read the PPD.
Dialogue: 0,0:08:09.69,0:08:13.72,Default,,0000,0000,0000,,That's very important because that gives\Nenough time to either go flat like this
Dialogue: 0,0:08:13.72,0:08:16.53,Default,,0000,0000,0000,,or to actually get indurated like that.
Dialogue: 0,0:08:16.53,0:08:19.76,Default,,0000,0000,0000,,One key point I want to make\Nis let's say you've got redness
Dialogue: 0,0:08:19.76,0:08:23.40,Default,,0000,0000,0000,,all the way around here. Do you actually\Nwant to measure the redness? No.
Dialogue: 0,0:08:23.40,0:08:25.29,Default,,0000,0000,0000,,You want to measure the induration.
Dialogue: 0,0:08:25.29,0:08:30.96,Default,,0000,0000,0000,,Just keep that in mind.\NInduration not redness.
Dialogue: 0,0:08:30.96,0:08:33.46,Default,,0000,0000,0000,,They are very, very easily\Nconfused for one another,
Dialogue: 0,0:08:33.46,0:08:37.00,Default,,0000,0000,0000,,but it makes a big\Ndifference. Not redness.