Double Vision

SPEAKER_00 0:11

Hello and welcome to the Home of Medicine Podcast, a podcast in association with the Royal College of Physicians Edinburgh. I'm Dr. Amy Burbridge.

SPEAKER_01 0:20

And I'm Dr. Ben Lovell.

SPEAKER_00 0:22

Ben, I have a case for you. Are you ready?

SPEAKER_01 0:26

Yes, I'm very excited.

SPEAKER_00 0:29

So this was a gentleman I saw on Post Take Ward Round, and he was in his 60s, and he presented with a one-week history of double vision.

SPEAKER_01 0:40

Oh, neurophobia kicking in. Okay.

SPEAKER_00 0:45

What are your thoughts when I say double vision?

SPEAKER_01 0:49

Okay. All right. I mean, what are my thoughts? My thoughts are um I'm gonna have to put my thinking cap on. Yes. This isn't gonna be a quickie. This isn't gonna be COPD, exacerbation, neb, steroids, antibiotics. So double vision, where where is the problem? Is the problem in his brain? Is the problem in his extraocular muscles, um, or is it the problem in the nerves that supply the extraocular muscles? So he's an ophthalmologia. So that's broadly how I think about it. I need to be absolutely sure it's double vision. He might say double vision and he might mean something else. He might mean blurred vision, he might mean uh tunnel vision. People who say double vision, you know, you need to pin on exactly what they mean. Um the other thing to say is it is there some kind of weird refractive problem, i.e. a corneal problem or a dislocated lens or something like that. But um, I I would try and work out if this truly is mental plegia, and then I'll try and work out where the lesion is from central to peripheral nervous system.

SPEAKER_00 1:46

Fantastic. I mean, that is yeah, brilliant. That's probably not what I did. Because um, as soon as I heard double issue, I was like, oh gosh, my anxiety started. And I flipped, I've talked about this before when we have type one thinking and type two thinking. So thinking fast and thinking slow. Thinking fast is when we we it's pattern recognition, we've seen something before, it's on the tip of our tongue, it's in our consciousness, we know it. When it comes to neurology, double vision, I really struggle. So I went into type two thinking, thinking slow, thinking methodically, going back to basics and really trying to figure out what was going on. So I'll carry on. He said he had a one-week history of double vision, which was present in both eyes. He described it as objects appearing four to six inches apart, and the diplopia, the double vision, resolved on covering either eye.

SPEAKER_01 2:49

Okay.

SPEAKER_00 2:50

He said he also had a permanent, noticeable low frontal headache all across the front of his head. He said it wasn't severe, wasn't really worried about it, and that had been present since the double vision, so for about one week. He actually wore glasses, and the double vision was present with and without the glasses as well. He denied cough, cold, chest pain, jaw claudication, speech changes, or any transient visual loss? He said he didn't feel nauseous, no scalp tenderness. He also reported that his left eye had a slight eyelid droop and he'd noticed that for about a day or two. Does that change anything? He's starting to think about anything.

SPEAKER_01 3:52

Droopy eyelids, I'm thinking about Horner syndromes. Have we looking at pupils and thinking about uh other signs of horners? Um, diplopia with a headache. So did he get the diplopia and now he's got a secondary headache through the F, you know, eye strain essentially, or is there some kind of pathology which is causing headache and double vision, such as thalmoplegic migraine? That's actually a contentious diagnosis at the moment. Some say people say there's no such thing as thalmoplegic migraine, and they they prefer to call it something called ARPOR, which is recurrent painful ophthalmic um neuropathy. Anywho, I'm getting ahead of myself. So I'm thinking about whether or not the headache is related to the double vision or whether it's a secondary effect. Um, but I'm still thinking, I'm still trying to think about the causes of diplopia from a central sort of brain problem, starting with strokes and demyelination, working my way down to the cranial nerve nuclei and then the cranial nerves and the extraocular muscles. So I'm gonna have to sit down and work that one out, but I've got a bit more information.

SPEAKER_00 4:48

Okay, what do you want to know? Any of the questions that you've got for me?

SPEAKER_01 4:52

Ever happened before?

SPEAKER_00 4:54

No.

SPEAKER_01 4:55

Do you get migraines or so?

SPEAKER_00 4:57

No.

SPEAKER_01 4:58

And you've never had any other um nerve problems, any numbness or weakness or strange paralysis that came and went?

SPEAKER_00 5:05

No, nothing at all. No.

SPEAKER_01 5:07

Are you a headache person?

SPEAKER_00 5:09

Not really, no.

SPEAKER_01 5:11

Okay. And um what else? What else? What else? Um, any changes that you notice to your pupil? I'll have a look myself in a minute.

SPEAKER_00 5:21

I mean, to me, my both of my pupils look a lot bigger. But I I don't know. I mean, it's difficult to say really.

SPEAKER_01 5:31

All right then. Any changes in sensation to your face or any weakness of your face?

SPEAKER_00 5:36

Nothing, apart from my left eyelid is a bit droopy, and my eye seems to be running a little bit more than normal.

SPEAKER_01 5:43

Hmm. And um did this come on suddenly?

SPEAKER_00 5:47

Yeah, I think so. Yeah. Just sudden onset of double vision. It doesn't feel like it's getting better or worse, it's just stayed the same.

SPEAKER_01 5:55

No speech disturbances. No, no, and he's walked into the consultation room, okay.

SPEAKER_00 6:00

Yeah. I mean, when I saw him, he it was on the post tape wardround, so I'd been seen the night before. Um, and he was sitting in on the side of the bed. Well, he was sitting in the chair at the side of the bed, dressed in his normal day clothes. Looked very well.

SPEAKER_01 6:18

Okay. And the double vision's not worse towards the end of the day.

unknown 6:21

No.

SPEAKER_01 6:21

When you're tired. No.

SPEAKER_00 6:23

Ooh, why do you ask that?

SPEAKER_01 6:25

Myasthenia gravis. It was one of the cases in my my Pacers exam back in 1832, or whenever I said to um so yeah, double vision worsening at the end of the day, fatigueable weakness, but nothing like that, no?

SPEAKER_00 6:36

No, no fatigue of any trauma.

SPEAKER_01 6:38

No history of thyroid disease, thinking of thyroid eye disease, no?

SPEAKER_00 6:42

No, no.

SPEAKER_01 6:43

Okay. Um, and no trauma. You haven't bashed your head or hit your head on this.

SPEAKER_00 6:47

No, no trauma.

SPEAKER_01 6:49

All right then. So, in terms of history presenting complaint, I'd like to move on now. Any past medical history of them?

SPEAKER_00 6:58

Diabetes. Oh, okay. Type 1 diabetic for 45 years, hypertension, non-alcohol-related fatty liver disease. And a few years ago, saw an ophthalmologist and was told that he probably had cataracts and glaucoma.

SPEAKER_01 7:20

Right, wasn't taking any eye drops.

SPEAKER_00 7:23

No, so it wasn't so medication that he was on was insulin on a basal bolus regime, statin, bendroflemathiazide, ferrosulfate, yeah, doxasin, omecrazole, aspirin, lisinopril, and not allergic to anything of note.

SPEAKER_01 7:45

Diabetes pinged for me there, um because diabetes can cause mononeuritis multiplexing, it can knock off a nerve due to microvascular um sort of many infarctions of a nerve. And I've seen diabetes cause a mononeuritis of the sixth nerve, causing um an abducence palsy. So um, has he noticed that the dipropia is worse on horizontal? Looky to the left or to the right, or is it it's it's in every direction?

SPEAKER_00 8:09

To be honest, I didn't ask that question.

SPEAKER_01 8:12

Um all right. Um, but that's something I'm thinking about now. So if if I can localize his dipropia to one direction or one nerve, then um I just wondered whether this was a mononyuritis second to diabetes. Social history, alcohol and um smoking?

SPEAKER_00 8:30

Doesn't drink any alcohol, never smokes, lives with his sister, and is retired now, but used to work within the healthcare setting. How old did you say he was? In his 60s.

SPEAKER_01 8:42

Oh, okay. Um fine. And no other drugs I should know about.

SPEAKER_00 8:47

No.

SPEAKER_01 8:47

No, he's not been taking over the counter travel sickness medications or anything like that, and antihistamines.

SPEAKER_00 8:55

Uh I didn't ask that. Why are you thinking that?

SPEAKER_01 8:58

Uh well, those um those patches you can stick on for the sickness once. If you rub them in your eye, you can get a um a dilated pupil and and uh vision problems if you if you sort of rub it, rub your eye afterwards, anyway. Case report stuff. Um, okay. Um I think that's enough data for me. I think it's time to examine the patient.

SPEAKER_00 9:20

Okay.

SPEAKER_01 9:21

What have we got?

SPEAKER_00 9:22

So this is how I start to panic with neurology because I I go, I can go through the motions, I can do the examination, paces style, neurological examination. However, when it comes to interpreting the findings, that's when I start to struggle because I may pick up on an abnormality, but I can't immediately think what that means. I have to write it down and then really think about what that means. Observation-wise, his heart rate was 94 and regular, blood pressure 140 over 74, temperature 36, respirate 14, saturations 96% on room air.

SPEAKER_01 10:05

Right, all normal.

SPEAKER_00 10:06

All normal. So he was very chatty, very alert. You know, we were having a really good conversation, and all the time while I was chatting to him, I was sort of observing him. What I did notice on sort of direct observation is he had quite a subtle left-sided tosis, I felt.

SPEAKER_01 10:26

Yeah, yeah.

SPEAKER_00 10:28

The pupils looked large, they're quite dilated, but he I didn't know. I mean, I didn't know whether that was normal for him or whether that wasn't normal for him. They were equal and reactive to light. There was no relative afferent pupillary defect noted. Upper limb and lower limb, normal, cardiovascular normal, respiratory normal, bilateral lower limb edema, quite dry skin. Now I'm gonna try and tell you what I found on his examination of his eyes. Now, this is where I really struggle. So, facial nerve examination revealed a mild weakness of the left aubicularis oculi.

SPEAKER_01 11:15

Wait, wait, wait, wait, wait, slow it down. Yeah, I know.

SPEAKER_00 11:17

It's it's okay.

SPEAKER_01 11:20

So he had a he had a droopy eyelid.

SPEAKER_00 11:22

He had a droopy eyelid. I'm trying to be part exactly. So you can tell this is my type two thinking. I was, I think I must have spent about an hour doing this. So he had a droopy eyelid, sensation was intact. He could raise both of his eyebrows symmetrically.

SPEAKER_01 11:34

Okay.

SPEAKER_00 11:35

No problem. The right eye, he was unable to move it laterally.

SPEAKER_01 11:43

Oh, okay. And the left eye was the tosis eye, is it?

SPEAKER_00 11:46

The left eye had a tosis.

SPEAKER_01 11:48

Okay.

SPEAKER_00 11:49

And I thought that he couldn't abduct the left eye either.

SPEAKER_01 11:57

Okay. So cannot abduct either eye.

SPEAKER_00 11:59

Either eye. No obvious visual field defect. Do you know what? I actually documented Ben. This is quite embarrassing because it makes me sound like way more intelligent than I am. I was like, oh, I think there's a subtle left inferior nasal quadrantopia.

SPEAKER_01 12:21

Well, you thought I think there is, so you don't know what can hold you to it later.

SPEAKER_00 12:24

I was like, what even is one of those? Oh dear me. So I honestly, when I talk about this, I feel anxious. So anyway, that was my examination, and I was incredibly proud that I'd managed to do that.

SPEAKER_01 12:36

Well done.

SPEAKER_00 12:38

I don't still don't. I didn't really know what it meant, to be honest. Um part from I shouldn't see neurology patients.

SPEAKER_01 12:50

Right. So when you said a right abducid nerve palsy, I thought, okay, here we go, I've got it. Um is this a microvascular issue affecting the the right sixth nerve, and that's why carbon abducts right eye, that explains a little bit of everything.

SPEAKER_02 13:03

Yeah.

SPEAKER_01 13:04

But but you said bilateral abduced nerve palsies. Now that's that's not going to happen, is it? You're not going to have mononeuritis multiple affecting the same nerve and line with site. And it doesn't explain the tosis. Um double vision and tosis. I was initially thinking of an oculomotor nerve palsy, a third nerve palsy, which could be caused by compression, a headache. You think about an aneurysm, although you'd expect him to be extremely unwell if he'd a posterior communicating artery aneurysm adverse. He had an intercerebral bleep, um, a little bit meningitic and photophobic, etc. But it's something squeezing his oculomotor nerve. I can't tie that within bilateral. Oh, hang on, maybe I can. So the sixth nerve is very vulnerable to pressure because it's got the longest course. And raised intracranial pressure can cause a false localizing sign of a sixth nerve Aussie, which has actually got nothing to do with the coarse nerves because there's high pressure in the brain. I've never heard of bilateral six due to high intracranial pressure, but theoretically it makes sense. Is there something compressing his oculomotor nerve leading to the tosis of the dipopia, which is now raised into cranial pressure to the point where both six nerves have been affected and he can't abduct either eye? He needs a CT head. Normal. He needs an MR on a head.

SPEAKER_00 14:27

Okay.

SPEAKER_01 14:29

Yeah. Yeah. Um, so that's where I'd be right now. If it were me on the post-take wardround, I'd be writing that down as potential potential ideas. My plan would be neurology review. I think I think when he's an MRI head, and I think I'd have to say, what's the quickest way of getting an MRI here? It's probably to admit, admit and get one. Are you post taking him in the morning?

SPEAKER_00 14:56

I am, yes.

SPEAKER_01 14:57

Yeah. Can you get staying day MRIs? Yeah, candy. Okay, yeah. Yeah. So I think I think I would say post-take board round, patient to stay, needs an MRI and a neurology review today, and then re-evaluate. It would be my post-take plan. Sorry, I I haven't really pinned down a diagnosis.

SPEAKER_00 15:16

It's really difficult, isn't it?

SPEAKER_01 15:18

But I've explained the plan. I was actually doing, I do these things called feedback clinics, um, our case-based discussion clinics where doctors, president doctors can can book in a time to come and bring the case to me. Some of the feedback I give to the ones who are registrars or coming up to registrar level, one of the tricks about the post-war, you think it's 90% doing the diagnosis, 10% then plan. There's actually other way around. Um the plan needs more consideration and thought or takes more precedence than the diagnosis at the ward round. And it took me a while to discover that as a post-staking consultant. Um, so I do sometimes say um diagnosis as yet unclear. Differential includes A, B, and C, but my plan has got to be nailed down bullet and detailed, especially in the era we work in where flow and bed space is absolutely critical, and deciding what can be worked out in versus outpatient versus STEM versus you know on my enhanced care unit on the world. Um, so I think I'd have a pretty decent plan for this guy, although I might still have prevaricate a bit on the diagnostic side. If that's if that's okay.

SPEAKER_00 16:24

And I had similar, I thought this could be diabetic, uh, microvascular complications. I didn't word it as beautifully as you did. Um, but I thought there was a third nerve palsy on the left and a sixth nerve palsy on the right, like a mononeuritis multiplex. I sort of ruled out giant cell arteritis because there was no um scalp tenderness, no chest pain.

SPEAKER_01 16:45

Sure.

SPEAKER_00 16:46

Vasculitis, unlikely.

SPEAKER_01 16:48

And by the way, that's not too bad a thought, giant cell artery, temporal arteritis, because that can actually present the complex photalmaplegia. So you imagine it to be just the headache and the vision loss and the pain, but they can get um alphaplegia as well. So it's a good thought.

SPEAKER_00 17:02

I also said, because it was bilateral, I need to rule out a posterior communicating arterial aneurysm. Um, I think that I mean it was incredibly well. And um, but again, it's one of those things that I don't want to be caught out with. So my plan was exactly the same as yours, MRI, neurology. I also gave him an eye patch. Um, just just we didn't have any at the at the time, so I gave him some um sort of pads. Yeah, absolutely. And I thought, let's get neurology, ophthalmology to review, and then we'll go from there. We'll also do some of the tests, let's look at his diabetic control, thyroid function, just see what's going on. And what was really unusual in this patient is that I saw him for three days running because he was on admitting ward on post-take, and then he was on our short stay area. So actually, it was really nice that I got the chance to follow him up, and that very rarely happens. So, as I said, the CT head was normal. I got a CT angio to check for the aneurysm, and again, that was normal. MRI head and orbit, moderate small vessel disease, but nothing else of note.

SPEAKER_01 18:18

Interesting. What else can cause what else can cause a complex of octalmoplegia? I mean, vernicus could do it, he says the alcohol. We thought about NMJ disorders, and we said no. Um, rare mitochondria cytopathies, nah. Um, I said thyroid eye disease. Millerfisher, I mean, it's not he's not associated with an ascending paralysis or GBS subspectrum thing. It's got no other signs at all. Um well, well, I mean, the the the third nerve nucleus and the sixth nerve nucleus, they don't sit near each other. Third nerve, I think, is midbrain, sixth nerve is pons. Um, so if he had a pattern of demyelation, for example, this is the first presentation of MS. Um, he's got two lesions there. They don't sit together.

SPEAKER_00 19:12

Um has he got two lesions? Because of my very poor examination technique with neurology, could I have misinterpreted the signs?

SPEAKER_01 19:22

Okay. Um, but the MRI is normal. Um, so that that's the end of that theory. So I'd be interested to know what neurology said here.

SPEAKER_00 19:30

Okay, so neurology came along and they said this man does not have a third cranial nerve palsy on the left. And I was like, he does? He's got a droopy eyelid. This is this must be a tosis, of course it is.

SPEAKER_01 19:43

I've just had an idea. Go on.

SPEAKER_00 19:45

Go on. No, go on, tell me your idea.

unknown 19:47

Go on.

SPEAKER_01 19:47

You know, you know his tosis eye. Was his eye red and inflamed and injected?

SPEAKER_00 19:52

Uh a little bit, yes.

SPEAKER_01 19:54

Okay. He wasn't having he wasn't having a glaucoma. He didn't have a glaucoma in the eye, did he? Acute glaucoma, headache, eye pain, through PI.

SPEAKER_00 20:03

He didn't because ophthalmologist assessed him, but that is a really good thought. Acute angle, acute closed angle glaucoma, which is a medical emergency, isn't it? Yeah. No, he didn't have that.

SPEAKER_02 20:14

So much for that.

SPEAKER_00 20:16

So neurology documented that he had a right six cranial nerve palsy.

SPEAKER_01 20:21

Right, six. Okay.

SPEAKER_00 20:23

The left side, there was nothing. They felt that the eye was normal. But they did say that, okay, we agree with you that there's something quite strange in the eye movements. And I was like, oh, okay. So I did a little bit of reading around. So we all know that when you damage the sixth nerve, the abducence nerve, it paralyzes the lateral rectal muscle, and you your eye can't turn outwards, and the eye drifts inwards towards the nose. The opposite eye has a full range of movement. This gentleman did have that. As the eyes work as a team, though, for example, the brain to get an accurate representation of what you're viewing, it sort of overcompensates and it sends extra signals to the nerves, and you get Herring's law of equal innovation. Have you heard of this? No, no, so Herring's law of equal innovation forces the opposite eye, the good eye, to work harder. And therefore, what I was seeing potentially in the left eye was Herring's law of equal innovation. It was trying to force the good eye to work extra hard.

SPEAKER_01 21:49

Do you know? I've never heard of that, and I love eponymous syndromes. I sort of collect them. I've never heard of Herring.

SPEAKER_00 21:55

Do you know I'd not heard of it? And it was doing some reading around and having a chat to a few different people. People is one of those things that some people believe exists and some people doesn't. But that can certainly explain maybe why when I was looking at the left eye, it was a little bit odd and it didn't quite fit. So a consultant neurologist came down and said, This man has a bilateral six nerve palsy, clinically presenting only in the right eye. Most likely due to moderate small vessel disease. Orthoptic assessment also said bilateral six nerve palsy, as well as the ophthalmologist.

SPEAKER_01 22:40

Now case closed, or is it it's not, I always say this to you, it's not a very satisfactory diagnosis. I know bilateral six, so due to small vessel disease, which is what we're saying, microvascular, probably related to hypertension of diabetes, has picked off both six nerve palsies at the same time.

SPEAKER_00 23:03

I know.

SPEAKER_01 23:04

I ain't buying it. I ain't buying that.

SPEAKER_00 23:06

It's really interesting, isn't it? And I that was the the final diagnosis, bilateral six nerve palsy. A few things to talk about. So even after this diagnosis had been given by three people now, so ophthalmology, orthoptics, sort of myself in a little way, neurology. Um there was a documentation from another member of staff to say this gentleman has not had ESR, CRP done, he's not had a full vasculitis screen, syphilis, HIV, antiphospholipid antibodies, and anchor screen. Please do them. Any thoughts about that?

SPEAKER_01 23:52

Well, I okay, I think some of those are a good idea because we want to do a mononeuritis screen, don't we? Or um monoplex screen. Now let's shall I see if I go in with then?

SPEAKER_00 24:01

Yeah, please.

SPEAKER_01 24:02

Um I'm writing them down on a bit of paper. Sowards PRC. So basically it is your um your vasculitis screen. Yeah. Um do you want to rule out uh polyangitis when you're donatosis? You want to rule out uh rheumatoid? Do you want to rule out diabetes when you've got already got that? You want to rule out um carcinomatosis? You want to rule out polyartheritis? So I think um anchor, HIV, well, sorry, auto-immute screen, HIV, ESR are really decent ideas. Yeah. I could take or leave the sit on this screen if I'm honest with you. Um yeah, I'm not very compelled to do that one. Um and of course it's already got uh I think his HBO1C might be useful even though he's got diabetes, just to see how well controlled it is.

SPEAKER_00 24:56

Mm-hmm. Yeah, okay. Um, he did have them all and they were all normal, sort of ruling out the vasculitis side of things. Now I just want to question something here. I don't know. I felt that because four different teams had given in the diagnosis of microvascular complications of diabetes.

SPEAKER_02 25:16

Yeah.

SPEAKER_00 25:17

Was it necessary for us then to do all of these expensive blood tests?

SPEAKER_01 25:23

Um I have thoughts about this because I remember when I was doing my um liver job, my gastro job as a as an SHO, and we'd have patients come to the um the outpatient department with a new diagnosis of liver disease, and they'd say, Yes, I drink 300 inches of alcohol a week. Yeah. And then they would still send a full liver screen, including like ceruloplasmin and alpha on antichipsin, and I'll be going, but what why? These are these are expensive tests for vanishingly rare conditions, and the patient's telling in a diagnosis. Um, they they've come in and said, Yes, I I drink and and this is what's going on. I always find it very strange they're doing that. And I guess I guess what they're trying to avoid is what we might call premature closure, which is grabbing the first diagnosis to say that must fit. Um, goodbye, let's all let's all go home for tea. So making sure you've not missed something useful. I still don't think we should be doing copper screening on people who super presented with a new liver disease because I I've never seen a Wilson's.

SPEAKER_00 26:23

Well me, actually.

SPEAKER_01 26:25

But I think I think we ought to be doing I think we ought to be doing due diligence. Yeah, okay. Patients can have two pathologies. They can. Hickum's dictum. And I think the patient who has who is being treated aggressively for complications of diabetes um might have a reason to be angry if it turned out 10 years down the line they had an untreated vasculitis because we just assumed we we knew the diagnosis. So I think I do there there is some wiggle room there for me, cognitively, for making sure that we have um we've excluded anything else which is treatable, reverse.

SPEAKER_00 27:01

Yeah. I think that's an really, really good and valid point. The most common diagnostic bias is premature closure. And yeah, we often close down, we've got a diagnosis that fits our pattern, and we stop looking for other things. But as you rightly said, people can have more than one disease. And I think I am really bad at I I really I don't I I really struggle with doing loads of investigations on people. And I think if we've got a diagnosis from four different people, I'm I'm I mean, I'm saying that I'm wrong by the way. I don't agree with the way that I do it. I'm like, think of all that money we're spending that could be going to other people who need it. You know, we're doing all of these tests, unnecessary tests. But like you say, they might not be unnecessary, and I have been caught out when I haven't done tests and I've made assumptions and I've prematurely closed and I've missed things.

SPEAKER_01 28:03

Well, think about the think about heuristics, mental shortcut that we take.

SPEAKER_00 28:09

Yeah.

SPEAKER_01 28:09

Um less thing, uh imagine uh don't think zebras. You know that one?

SPEAKER_00 28:14

So yeah, think donke not donkeys. Is it donkeys? Horses, no, it's not horses.

SPEAKER_01 28:20

Horses, it's not called yeah, don't think zebras or donkeys. If you hear hoof beats, it's probably a horse.

SPEAKER_02 28:28

Might be a donkey.

SPEAKER_01 28:30

Because yes, because uh maybe that was different if you live in zebras. More common, but for uh certainly for me in that don't think zebras is a good is a good rule of thumb. And a heuristic or a rule of thumb, that mental shortcut that we take our clinical reasoning. Um, and I often hear them discussed in uh human factors um negatively, saying oh heuristics leave us open to errors and and um it's it's thought that bias, which is sort of true, but I always think about them quite positively. Heuristics are really useful mental shortcuts sometimes, and they save you a lot of extra processing and thinking by recognizing patterns and making a jump from A to B and getting a diagnosis quickly and safely, and they work most of the time. The trick comes with being open and uh keeping one part of your brain open to the thought that maybe this isn't what it is. Yeah, and I think if you come with me on my posted ward rounds, I was on take last five day and I went in. The night team looked like they'd been through something pretty intense. There's about 30 patients to post-tag, and I had to do it in the next four and a half minutes or something, Cindy. And I relied on heuristics to get me through that quickly. What's the diagnosis? What's the patient's story? Let me look at them. Yep, this is right, this is right. Treat with one, two, three. Okay, who's the next patient? I don't have the chance to work up the hypothetical deductive model every time, which is how I start as a medical student. But let's piece all of these things together and then theoretically work out what could be the diagnosis. I have to do some leaps. Um, and I have to sort of comfort myself saying, look, if I leap in the wrong direction, the patient is in a safe place. The pattern that we have here of re-review, re-review, re-review means other intelligent people are going to see them and hopefully stop me from doing anything which might turn into harm or a near myth. Um, and a few times a year, I do discover times where um I my heresy didn't work.

SPEAKER_00 30:23

Yeah.

SPEAKER_01 30:23

Um I it was a zebra. I met a zebra and I and I thought it was a horse. If I can just keep stretching that 94 out. But you can't go into a thinking, I must spot all the zebras today. You you have to be able to rely on rule of thumbs and chances and Bayesian analysis to try and work the one thing to safety 99% of the time. And I think it's worth remembering that in the NHS, many healthcare systems, we are just repeatedly and constantly churning through millions of patients and helpers a week, and we are getting it right most of the time. And we do focus on the times that goes wrong because we want to learn. And sometimes those schools can be inconveniencing or tragedies to patients. Um, but I do think that the focus we have on when things go wrong out of good intent sometimes leads you to a false sense that things go wrong all the time.

SPEAKER_02 31:13

Yeah.

SPEAKER_01 31:13

And we are just we're just cracking on and getting things right in a very boring, unexciting, and glamorous way, um, all the way from the front door of A E to the pharmacy and the high street and all those clinical spaces in between. Um, but to make that change, senior decision makers have to use heuristics to make very, very quick decisions.

SPEAKER_00 31:35

Um it's I think the I say this all the time, I'm getting wiser, older. Because I made what I feel was a big medical error 10 years ago. I really struggle with heuristics and the quick thinking now. And I feel like I'm slower, and I've mentioned this to you many times than I was before because I have to do the hypothetico-deductive reasoning on every patient, and it's ridiculous. And I can't, there's something that stops me from following my gut instinct, from using my heuristics because I'm so scared of messing up, and I don't want to be that person who everybody goes, Oh god, you don't want to see her. She's doctor Amy, she's really bad, she's a terrible doctor. And I I don't know, it's it there's a lot of I guess psychology and some professional identity issues I've got there potentially, but that's the human factors that affect you as you work.

SPEAKER_01 32:40

Hey, at least you know them. A lot of people often not knowing what's what affects how they work and why they make the decisions that they make in principle ignorance.

SPEAKER_00 32:48

True. Good point. So I hope that that was uh interesting case for you, Ben. I think it's sparked a good discussion, actually, as to how we think, as to how we work, and certainly recapture premature closure.

SPEAKER_01 33:04

I think in this case as well, there would be a patient who I might rec I would definitely recognize, say this isn't gonna be a quickie, is it? Or say around with I'm gonna have to come back to this one when I've split my brain on a bit later on today and have a proper think and go into hypothetical deductive mode. I'm gonna have to piece this from the ground up because this I haven't got a pattern that fits too. I haven't got a number that's fit this is matching to in my brain. Exactly. I'm gonna have to use use my brain cells on this one. And I think knowing when to when to sit down and take your time, and that often doesn't look very exciting. It looks like me sitting at a computer slowly tapping away two-finger typing, and then someone coming up and saying, Oh, can I help you with anything, Dr. Love? No, I've got to type this out myself because it's it's it's helping me think. And I've decided what the diagnosis is. Hopefully I'll say at the end. And sometimes I still say I don't.

SPEAKER_00 33:53

Yeah. And that's yeah, that's a really good point, actually. Maybe you know, some of these cases I can get there quicker. And when I can't, I just have to take that time and say, actually, I'm gonna sit down and figure this out for myself.

SPEAKER_01 34:05

Yeah.

SPEAKER_00 34:06

Thank you so much, Ben. As ever, you're a font of knowledge and reason. Thank you to all of our listeners out there. We are gaining subscribers. And a couple of weeks ago, we were number five in the medicine podcast charts in the UK, which is incredible. So I'm very proud five hits.

unknown 34:28

Yay!

SPEAKER_00 34:29

Um, so please rate review and subscribe to the podcast. If you have any feedback, please drop me an email at amy at homeofmedicine.com. And a massive thank you to the Raw College of Edinburgh. Thanks for listening. Bye.