Full transcript
0:00today I'm gonna do a quick video about
0:02optic neuritis I'm going to talk about
0:04what it is the general symptoms how we
0:07diagnose it the medical conditions
0:09that's associated with and how to treat
0:12it so generally speaking optic neuritis
0:14is abnormal inflammation of the optic
0:17nerve the nerve that connects the eye to
0:20the brain and allows you to see an optic
0:23neuritis can cause temporary or
0:25permanent visual loss and typically it's
0:29associated with an autoimmune response
0:31against the optic nerve in some cases it
0:34can be due to a direct infection of the
0:36optic nerve but usually it's immune
0:39mediated now usually the symptoms of
0:42optic neuritis develop fairly slowly
0:44they develop insidiously
0:46over a couple of days or even several
0:48days and usually the symptoms start with
0:51pain although sometimes they can start
0:53with visual loss and the typical history
0:55would be paying with eye movement you
0:57just have a little bit of nagging pain
0:58as you look around and it sort of
1:00irritates your eye generally speaking
1:02the pain is not excruciating but it can
1:05be pretty severe in some cases and the
1:08pain often precedes the visual loss and
1:10then the visual loss evolves slowly
1:12starting off minor but in some cases
1:15becoming very severe and usually the
1:18visual loss is a little bit more towards
1:19the center of the vision and so the
1:22peripheral vision may be intact but the
1:24central vision is very impaired and you
1:26may even note like a small white dot or
1:28fuzzy circle in the center of the vision
1:30typically optic neuritis involves one
1:33eye at a time although in some cases it
1:35can involve both eyes particularly with
1:38the condition neuro myelitis opteka but
1:40with optic neuritis not associated with
1:43that condition or associated with
1:44multiple sclerosis it usually involves
1:46one eye at a time and often the symptoms
1:50disproportionately affect color vision
1:52so even if the overall visual acuity is
1:54not that much decreased the color vision
1:57can be impaired and sometimes I'll have
1:59a patient look at something red and then
2:01cover one eye and the other and
2:02sometimes they'll notice that the red
2:04looks brighter with the unaffected eye
2:06and that suggests that the color vision
2:08is as effective known as red colored
2:10saturation and that can be a sign of
2:12optic neuritis
2:13and you know some of the tests that we
2:15use to evaluate optic neuritis are
2:17visual acuity so we can use a Snellen
2:19chart or handheld card and we'll measure
2:21visual acuity as a general rule of thumb
2:24if the visual acuity is very bad worse
2:28than 20 over 200 in other words if at 20
2:32feet you can't see what a normal person
2:34could see at 200 feet in other words a
2:37very impaired vision you're kind of less
2:39likely to have a good recovery however
2:42if the visual acuity is 20 over 100 or
2:45better there's a pretty good chance of
2:48having a good recovery now good recovery
2:50may not be completely normal vision you
2:52could have had 20/20 vision before and
2:54it returns to 2025 you may have 20/20
2:58vision but you have a little central
2:59area of visual loss known as a central
3:02scotoma but generally a good usable eye
3:05in other words fairly good recovery some
3:09of the other tests that we do are a test
3:11called the swinging flashlight test so I
3:13shine a light in your eye and then move
3:15it to the other eye and the idea is that
3:17you have a light reflex known as the
3:19pupillary light reflex so when I shine a
3:21light in my right eye
3:23both of my pupils constrict I'm not sure
3:25if you can actually see that and the
3:27reason is because you have afferent
3:28fibers from your optic nerve that don't
3:31go to the occipital lobe the visual area
3:34of the brain they go to another nucleus
3:36called the edinger Westfall nucleus and
3:38then they have motor fibers going to
3:40both eyes that constrict the pupils in
3:42other words so you shine light and one
3:44pupil both eyes should constrict but
3:47let's say I have right optic neuritis
3:48there's impairment on the right optic
3:51nerve then I would share in a white in
3:53the left eye and both of my pupils would
3:56constrict and then I would move it to my
3:58right eye and both of my people who
4:00would die late because the afferent
4:01fibers are impaired that's known as the
4:04swinging flashlight test another thing I
4:07might do is ophthalmology here's my
4:08trusty a family scope I would look in
4:10your eye and what I'm looking at is the
4:12optic nerve and in some cases the optic
4:15nerve can appear swollen the borders can
4:17be abnormal the venous pulsations which
4:20are normally present can be diminished
4:21and then I might look for other things
4:23that could cause visual loss although
4:25I'm not an optimum
4:26just so I can easily overlook things and
4:28in many cases papilledema or a swelling
4:31of the optic nerve is actually not
4:33present and the reason is probably
4:34because it's not severe enough or the
4:36inflammation is further back towards the
4:39brain known as a retro bulb our optic
4:41neuritis so I'm really not going to see
4:42anything and your optic nerve will just
4:44look normal
4:45some other tests that can be done or
4:47visual field testing where you look and
4:50you press the button every time that you
4:52see something that a computer is showing
4:53to you and we mapped out your visual
4:55fields and often optic neuritis there's
4:57a little central scotoma or central seco
5:00scotoma an area of vision loss near your
5:03blind spot or near the center of your
5:05vision sometimes we'll do ocular
5:07computed tomography we'll sort of scan
5:10the retina and optic nerve and measure
5:12the retinal fiber thickness and that's
5:14good for diagnosing other conditions as
5:16well sometimes we'll do something called
5:18visual evoked potentials we'll put
5:20electrodes on your occipital lobe and
5:23show you a flashing checkerboard happen
5:25and measure how long it takes the
5:27information to get from your eye to your
5:29brain and if that time is prolonged
5:32particularly in one eye compared to the
5:34other that can be a sign of optic
5:36neuritis and interestingly even if you
5:38had optic neuritis many years ago and
5:40recovered to normal vision that test
5:42will often still be abnormal
5:44another test will sometimes do is an MRI
5:47scan of the orbits although it's not
5:49very sensitive I've seen many cases
5:50where someone clearly has optic neuritis
5:52but the MRI of the orbits is completely
5:55normal
5:55now what about the causes of optic
5:57neuritis sometimes it's just an idiot
6:00sink radix it happens for no particular
6:03reason and we don't know why and it's
6:04not associated with any chronic disease
6:06and it never happens again sometimes
6:09it's related to something that
6:10stimulates the immune system so you get
6:13a virus you get an upper respiratory
6:14tract infection you get a little bit of
6:16diarrhea and then a few weeks later you
6:18get optic neuritis and we think this has
6:20to do with molecular mimicry maybe
6:22there's something in the virus that sort
6:24of resembles your optic nerve and it's
6:26sort of tricking your immune system into
6:28attacking the optic nerve sometimes this
6:30it can occur after a vaccination but
6:33believe it or not it generally does not
6:35recur after another vaccination so even
6:38in people who had vaccine
6:39used optic neuritis the risk of it
6:41happening in the future with another
6:43vaccination is relatively low because
6:45it's sort of an idiosyncratic event of
6:47course the most feared disease after
6:49optic neuritis would be multiple
6:51sclerosis and in about 20% cases of
6:55multiple sclerosis the very first
6:56symptom is optic neuritis there was a
6:59famous study published in the 1990s
7:01called the optic neuritis treatment
7:03trial and what they found is that the
7:05best predictor of the risk of multiple
7:07sclerosis after optic neuritis is the
7:10MRI of the brain and if the MRI of the
7:12brain is completely normal absolutely no
7:15abnormal lesions associated with
7:17multiple sclerosis the risk of
7:19developing multiple sclerosis is
7:20actually quite low maybe only about 20%
7:22over 15 to 20 years however if there are
7:26already many lesions that look typical
7:29of MS the risk of multiple sclerosis is
7:31quite high now I should give the caveat
7:33that for a lot of people they actually
7:35have white matter abnormalities on their
7:38MRI that do not look like MS they appear
7:40benign or related to vascular disease
7:43and so that's a common cause of
7:44confusion but there are other autoimmune
7:46diseases that can also cause optic
7:48neuritis like lupus or Sjogren's
7:50syndrome or neurosis and then of course
7:53neuro myelitis optica can cause optic
7:55neuritis one thing about neuro myelitis
7:58optic is often it causes more severe
8:00optic neuritis that's less likely to
8:02lead to a good recovery and more often
8:06at least two optic neuritis
8:07simultaneously of both eyes and of
8:10course neuro myelitis optica can be
8:12diagnosed with certain antibody tests
8:14such as the anti aquaporin for antibody
8:17that is positive in about 70 percent of
8:19cases now there's some other diseases
8:22associated with optic neuritis one of
8:24them is this disease called creon which
8:26is chronic recurrent inflammatory optic
8:29neuritis and this disease optic neuritis
8:31can often occur again and again and
8:33again and there's no specific cause it's
8:35not associated with multiple sclerosis
8:37anti aquaporin 4 can be negative there's
8:40no other autoimmune disease and in my
8:42experience this can occur many many
8:44times I've had some patients with like
8:4610 episodes of optic neuritis and I find
8:49that in this condition the prognosis is
8:50usually pretty good the vision often
8:52keeps
8:53back now there's this new antibody
8:56called anti MOG anti myelin
8:59oligodendrocyte glycoprotein which is
9:02present in about two percent of people
9:04who have neural myelitis opteka and it's
9:07also seen in some people who have Creon
9:10so this is sort of a new antibody that
9:12we can test for and we've just
9:13relatively recently been testing for it
9:15more routinely in people with optic
9:17neuritis now as i mentioned before
9:19sometimes optic neuritis can be
9:22infectious and there's certain
9:24infections such as tuberculosis
9:25cat-scratch disease lyme disease even
9:28cryptococcal meningitis that can
9:30directly infect the optic nerve now one
9:33thing about cat-scratch disease is it
9:35usually doesn't cause optic neuritis it
9:37usually causes Koryo retinitis and you
9:40can discriminate that to be between the
9:42two because the macula is involved in
9:44Koryo retinitis and on off the Mosca P
9:46you can actually see a macular star and
9:49I'll show you a picture of that here now
9:51what about the treatment of optic
9:53neuritis the typical treatment of optic
9:55neuritis is high-dose steroids so the
9:58most commonly used treatment would be
9:59methylprednisolone or solu-medrol a
10:02thousand milligrams and an adult
10:04intravenously daily for 3 to 5 days and
10:07sometimes we'll give them a lower
10:09tapering dose of prednisone after that
10:12now in the optic neuritis treatment
10:14trial the randomized trial from the
10:161990s we found that steroids don't
10:19necessarily change the ultimate
10:21prognosis of optic neuritis because a
10:23lot of people get better anyways it just
10:25may help people get better faster and so
10:28it doesn't necessarily change where
10:30you'll end up in a couple of years but
10:32it may help you get there a little bit
10:33faster now they actually found that
10:36high-dose IV steroids were more
10:39effective than low-dose oral steroids
10:41however a relatively recent European
10:44trial showed that for multiple sclerosis
10:46relapses including optical itis high
10:49dose oral prednisone is just as
10:51effective as I me solu-medrol or
10:53intravenous methylprednisolone but you
10:56have to give the same dose and in this
10:58European trial they actually used oral
10:59methylprednisolone which isn't readily
11:01available at high doses in the United
11:03States so in a lot of United States dr.
11:05and will do is they'll actually give
11:06pregnant
11:0750-milligram talents but you have to
11:09take 25 tablets daily for three to five
11:13days so 25 all tablets but at least it
11:16prevents you from having to go into the
11:17infusion center and believe it or not
11:19the risk of gastrointestinal side
11:21effects seems to be about the same but
11:24for both regimens you have to take in
11:27antacids such as prilosec while you're
11:29taking the steroids otherwise high-dose
11:31steroids can be very dangerous and can
11:33even cause stomach ulcers now some
11:36people don't respond to steroids and
11:38have very severe optic neuritis and will
11:40do another treatment called
11:42plasmapheresis if you want a little bit
11:44more of information about plasmapheresis
11:45I'll put the card to a dedicated video
11:47on this topic but plasmapheresis is
11:49basically a procedure similar to
11:51dialysis designed to remove antibodies
11:54and other inflammatory mediators in the
11:56blood and it has its own side effects
11:58and in some cases will use alternate
12:01treatment alternative treatments for
12:03optic neuritis such as intravenous
12:04immunoglobulin syn multiple sclerosis
12:08but can be used in other causes of optic
12:10neuritis and sometimes even heavy-duty
12:12immunosuppressants such as cytoxan and
12:15things like that now one thing that I
12:17want to mention is even when people
12:19recover from optic neuritis sometimes
12:21their symptoms will come back years
12:23later and a typical history is you know
12:26my eye is fine my vision is fine but
12:28when I'm exercising I get a little
12:30blurry vision in that eye or when I'm
12:31taking a hot shower or when I'm ill and
12:34have a fever I get a little blurry
12:35vision now this is a well-known
12:38phenomenon known as utah's phenomenon
12:40what's happening there is that there
12:43isn't actually new damage to the optic
12:45nerve but you're experiencing sort of a
12:48recrudescence of old injury to the optic
12:51nerve so the idea is that you have this
12:53inflammation of the optic nerve it kind
12:55of goes away and the nerve heals but it
12:57may heal abnormally for instance if we
13:00could look under the microscope we may
13:02see that the myelin is thinner than the
13:05normal optic nerve we may see the normal
13:07junctions between areas of transmission
13:10known as nodes of ranvier are sort of
13:12closer together in the damaged optic
13:15nerve even if it heals and as such it
13:17may be more susceptible to physiologic
13:20changes
13:21such as increase in temperature exercise
13:23stress heat illness etc and that is what
13:26we believe is the physiologic basis of
13:28Utah's phenomenon so generally speaking
13:31it's nothing to worry about there's no
13:32new optic nerve damage occurring anyways
13:36I hope you enjoyed the video and if you
13:37have more questions about optic neuritis
13:39or requests for future videos please
13:42post in the comments below