Question regarding the cornea...

[hoomer]

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Hi, im a first year ophthalmology resident and i have a few doubts i havent been able to solve. I cant find any literature that answers my questions so i decided to turn to you.
So here are my questions:

1 - How do u differenciate an actual stromal keratitis from an old scar?? (on observation only)
2 - How do u distinguish between an nonsuppurative keratitis and a suppurative keratitis in a very early stage?
3 - How do u distiguish between a stromal keratitis and a corneal oedema
4 - Why does an epithelial defect in the cornea cause photofobia?
5 - How does pain from a corneal ulcer dissapear with a cycloplegic?

Thanks alot people

 

[Andrew_Doan]

Thanks for posting and welcome to the forum!

1 - How do u differenciate an actual stromal keratitis from an old scar?? (on observation only)

Look for active inflammation (redness & edema) and presence of inflammatory cells associated with active stromal keratitis.

2 - How do u distinguish between an nonsuppurative keratitis and a suppurative keratitis in a very early stage?

This can be difficult at very early stages. The best thing to do is follow the patient soon and regulary after initiating treatment.

3 - How do u distiguish between a stromal keratitis and a corneal oedema

Corneal edema is only corneal swelling without presence of inflammatory cells. A stromal keratitis will have white blood cells and may have a whitish infiltrate that is different than the cloudy cornea seen with just edema.

4 - Why does an epithelial defect in the cornea cause photofobia?

There may be an underlying iritis (associated with the defect) that causes the iris and ciliary body to be sensitive to light as they must constrict. Also, the defect can cause glare and other visual problems associated with diffraction of light which causes photosensitivity but not pain associated with photophobia.

5 - How does pain from a corneal ulcer dissapear with a cycloplegic?

There may be an underlying iritis with a corneal ucler so a cycloplegic helps reduce pain associated with iris and ciliary body constriction and dilation.

 

[hoomer]

Thanks alot Andrew_Doan. That helped a lot but regarding question 1, imagine you patient comes because of a foreign body or anything else that would cause ciliary injection. How would you know if that white thing you see is an old scar or a new infiltrate??

And a few more things:
1- i heard some colleagues say something like " that are blood cells" regarding a patient with little hyphema and a suspected uveitis. Why cant they be inflamatory cells, i mean you cant distiguish the color can u?
2 - tha same thing with a patient whose retina cant be visualized because the vitreous is cloudy. When you dont see actual blood clots how can u be sure is really blood? And when u se some reddish cells, how do u distinguish them from tobaco dust??

Thanks alothttp://forums.studentdoctor.net/member.php?u=17329

 

[Wolverine98]

And a few more things:
How would you know if that white thing you see is an old scar or a new infiltrate??

1- i heard some colleagues say something like " that are blood cells" regarding a patient with little hyphema and a suspected uveitis. Why cant they be inflamatory cells, i mean you cant distiguish the color can u?
2 - tha same thing with a patient whose retina cant be visualized because the vitreous is cloudy. When you dont see actual blood clots how can u be sure is really blood? And when u se some reddish cells, how do u distinguish them from tobaco dust??

1- With a small hyphema, there will be some inflammatory cells from the blood. Usually in that situation, the blood is the primary concern. If you're talking to the patient, you talk about bleeding in the eye, they will have a much easier time understanding it than if you start to talk about RBCs, WBCs, inflammatory cells, etc. Sometimes you can distinguish between RBCs, WBCs, but it's difficult, and there are times when you definitely can't tell.

2-It's tough to distinguish tobacco dust from RBCs. Sometimes you can't. If the view to the retina is really hazy, it's likely RBC, because usually you won't get enough pigment release to block your view. However, does it make any difference functionally? I would argue no. If you see either, you have to check the entire retina as well as you can to look for a tear, hole, or detachment. If you've exhaustively searched, and you can't find one anywhere, it's probably RBCs. If you've searched and found a break, does it really matter if those cells are pigment or RBC? Not really.

Scar versus infiltrate. I've seen two cornea docs look at the same eye on the same day and have them disagree on whether something is a scar or very early infiltrate. Generally, a scar has a lighter, greyer haze to it than an infiltrate, which tends to be more opaque. Telling the difference will come with experience. So what do you do if you see this at 2am and you're not sure? You treat it as an infiltrate and bring the patient back the next day and have one of the attendings take a look. If they say it's just a scar, that's fine, you used some unnecessary abx. You don't want to assume it's a scar and have it turn out to be an infection that you missed. Err on the side of patient safety.
Also, a thorough history can really be your friend in this situation.

Some of these questions involve things that take experience, and no book is really going to help you. Also, some of them are things that people in practice for 30 years can't give you a definitive answer. I think you're getting yourself too caught up in minutiae for someone who is less than 3 weeks into residency. Now is a time for starting with the big picture, then worry about the smaller details.

 

[Andrew_Doan]

I think you're getting yourself too caught up in minutiae for someone who is less than 3 weeks into residency. Now is a time for starting with the big picture, then worry about the smaller details.

Well said! Bigger picture is more important at this stage.

 

[hoomer]

2-It's tough to distinguish tobacco dust from RBCs. Sometimes you can't. If the view to the retina is really hazy, it's likely RBC, because usually you won't get enough pigment release to block your view. However, does it make any difference functionally? I would argue no. If you see either, you have to check the entire retina as well as you can to look for a tear, hole, or detachment. If you've exhaustively searched, and you can't find one anywhere, it's probably RBCs. If you've searched and found a break, does it really matter if those cells are pigment or RBC? Not really.

I saw a patient, non-diabetic, with acute diminuishing of visual acuity.
Notinhg to say about the anteroir segment. When i tried to inspecto the retina it was very hazy. I assumed it was a vitreous hemorhage, but then i saw cells in the anterior vitreous. And there was no way i could inspect the whole retina
My questions is:
If they are blood cells the patient can wait a few days/weeks to clear the blood and the be reavaluated. If its tobacco dust its from a retinal tear an an imediate surgery has to be done.
Right??

 

[Wolverine98]

I saw a patient, non-diabetic, with acute diminuishing of visual acuity.
Notinhg to say about the anteroir segment. When i tried to inspecto the retina it was very hazy. I assumed it was a vitreous hemorhage, but then i saw cells in the anterior vitreous. And there was no way i could inspect the whole retina

If you have a VH, you often have cells in the anterior vitreous, so seeing cells there certainly does not rule that out.
Also remember that there are many other reasons that one can get a VH besides DM.

If they are blood cells the patient can wait a few days/weeks to clear the blood and the be reavaluated. If its tobacco dust its from a retinal tear an an imediate surgery has to be done.
Right??

If it's tobacco dust from a retinal tear, you would prefer to do laser rather than immediate surgery. However, it's tough to laser what you can't see.

Inspect the retina as well as you can. Could you see if it was flat? If not, do a B-scan. If the retina is flat, have the patient sleep with their head elevated, no reading, limited activity, and check again the next day. If you can't find a hole and the retina is flat, are you going to take the patient to the OR with all of its inherent risks just to find out if there's a hole because you're not sure if it's tobacco dust or RBCs? I hope not.
I've seen patients with tears who, for a variety of reasons, couldn't be completely treated with laser immediately and did not progress to an RD. Obviously you want to do it as quickly as possible, but sometimes real life doesn't allow that to happen.

As for "immediate surgery", even that is far from set in stone. The traditional teaching with an RD is to "never let the sun set on a macula-on detachment". However, there's not a ton of strong evidence for that thinking, and many people now are more willing to schedule the patient for surgery the next day or, in some cases, even day after that for surgery. How that goes will depend on the retina staff in your department, and it's best to discuss the issue with them. Different staff within the same department may deal with it differently, so it's good to know how they each feel about it.

In this situation, obviously another thing you need to consider is an endogenous endophthalmitis. From what you said, the rest of the eye sounds quiet, so that obviously would be much less likely, but it's just something to keep in mind.

 

[hoomer]

Inspect the retina as well as you can. Could you see if it was flat? If not, do a B-scan. If the retina is flat, have the patient sleep with their head elevated, no reading, limited activity, and check again the next day.

Why shouldn't the patient read???
In what other situations shoud i advise the patients not to "over-load" the ciliary muscle??

 

[Wolverine98]

Why shouldn't the patient read???
In what other situations shoud i advise the patients not to "over-load" the ciliary muscle??

It's not about the ciliary muscle in this situation. It's pure movement. The eyes move a lot when we read. They move back and forth frequently and rapidly. This agitates all those blood cells you want to settle out.
For this reason a lot of people like to have their VH and their hyphema patients refrain from reading.