Sudden Painless Vision Loss - Essential GP Revision

Sudden painless vision loss for general practice exams.

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Transcript

SPEAKER_01 0:00

Hi, this is Tom, and welcome to the Zero to GP podcast. In this episode, I'm going to be going through sudden painless loss of vision. All the key stuff you need for your GP exams. The format, as always, in these episodes is I'm going to present you with cases, ask you questions, I want you to come up with your answer, and ideally write that answer down or say it out loud, and then I'm going to go through an explanation. So let's jump straight into this episode on sudden painless loss of vision. The first case is a 45-year-old woman, and she presents with a central scotoma, which developed over 24 hours. Now central scotoma means an enlarged blind spot. So in the central part of her vision, there's an enlarged gap in the vision. So when you use your hat pin to test her blind spot, there'll be a large blind spot area in her vision. She also has pain with eye movement. So when she moves that particular eye, there's pain on movement.

SPEAKER_00 1:10

My question to you is what's your suspected diagnosis in this case?

SPEAKER_01 1:22

So in this case, we're suspecting optic neuritis, which is inflammation of the optic nerve at the back of the eye.

SPEAKER_00 1:30

My question to you is, what are the causes of optic neuritis? You can kind of group these causes into three categories.

SPEAKER_01 1:51

The first is demyelination. So everybody thinks of multiple sclerosis when thinking of optic neuritis, and that's the most common cause. There are other isolated causes of demyelination in the optic nerve, but a key one to remember is optic neuron uh is multiple sclerosis. The second is inflammatory conditions or inflammation, for example in systemic lupus, erythematosis, or sarcoidosis. And the third one, which is a bit more rare, is infection, for example, in syphilis. Okay, on to the next case. We've got a 68-year-old man, and he presents with sudden onset vision loss. So it happens almost instantly, the vision in one eye disappears. And you have a look in the back of his eye, and this is what you see on fundoscopy.

SPEAKER_00 2:45

So based on this presentation and the fundoscopy finding, what's your diagnosis here?

SPEAKER_01 3:00

Here you're suspecting central retinal artery occlusion, which is like a stroke where there's a blockage of the central retinal artery, blocking the blood supply to the retina. And the key findings you can see here on fundoscopy are a very pale retina, because there's no blood supply, it becomes pale, and this red spot at the fervia, that is called a cherry red spot. So if you see a cherry red spot and a pale retina, think of central retinal artery occlusion.

SPEAKER_00 3:33

My question to you is what are the two key causes of central retinal artery occlusion? The first is atherosclerosis.

SPEAKER_01 3:56

So this is cardiovascular disease very similar to a heart attack or a stroke. There's atherosclerosis or plaques building up in that central retinal artery that causes it to get blocked. Think of risk factors like older age, smoking, high cholesterol, hypertension, and so on as risk factors for atherosclerosis. The second cause is giant cell arteritis, which is a type of vasculitis. It affects older white patients typically, and think of that if the patient has temporal artery tenderness up here, jaw chordication, so as they chew or talk, their jaw becomes achy. In that case, think of giant cell artisans. Giant cell arthritis requires immediate treatment with high dosteroids, which could potentially be a reversible uh reversible cause, but um, yeah, so they need slightly different treatments. Okay, on to the next case, which is a 76-year-old woman, and she has sudden peripheral vision loss, which is like a shadow coming across the vision. And there's a history of flashes and floaters. When you look in the back of her eye, you can see this strange sort of wavy appearance to the retina.

SPEAKER_00 5:21

What's your diagnosis here?

SPEAKER_01 5:36

This is a case of retinal detachment, which is where there's separation in the retina of the neurosensory layer, which contains the rods and cones and nerves, and the retinal pigment epithelium below it. So that the retina is detaching, and that's what causes this abnormal, sort of wavy, strange appearance of the retina. This is again an ophthalmology emergency. In fact, all of these are ophthalmology emergencies, they require immediate referral to ophthalmology for same-day assessment. Um one of the key things here is the shadow coming across the vision and the history of flashes and floaters. Okay, on to the next and final case, which is an 80-year-old man and he presents with painless blurred vision over 24 hours. And you can see sort of this retina at the back of his eyes covered in hemorrhages and engorged vessels.

SPEAKER_00 6:37

What's your diagnosis here? This patient has retinal vein occlusion.

SPEAKER_01 6:54

So, like retinal artery occlusion, where the blood flow into the eye through the artery is blocked, here we have vein occlusion. So the blood drainage from the retina is blocked. And this causes engorgement of the retinal veins, retinal vessels, hemorrhages, cotton wool spots, and it can cause macular edema and new vessel formation and so on. The final question on this case is what is the kind of description of the appearance of the retina in retinal vein occlusion? This is described as a blood and thunder appearance because it's kind of stormy and it looks like there's you know hemorrhages throughout the back of the retina. So if you see blood and thunder appearance in your exams, think of retinal vein occlusion. So that's all the cases on sudden painless loss of vision. Hopefully, this was helpful, and I'll see you in the next episode.