The Curious Incident of the Dog in the Diagnosis

 

“Is there any point to which you would wish to draw my attention?”

“To the curious incident of the dog in the night-time.”

“The dog did nothing in the night-time.”

“That was the curious incident,” remarked Sherlock Holmes.

Sir Arthur Conan Doyle, Silver Blaze

We can learn a lot from Sherlock Holmes.

If there’s anybody who better personifies the ultimate diagnostician, I don’t know who. Sir Arthur Conan Doyle, creator of the Holmes canon, was himself a physician and purportedly based his famous detective on Dr. Joseph Bell — who, it was said, could glean a dozen esoteric facts of a patient’s background, history, and complaints from a single glance. (Holmes himself, of course, was not a medical man; that role was played by Watson, the earnest physician who carried his stethoscope wrapped inside his hat.)

Holmes didn’t diagnose illness. Instead, he diagnosed crimes. But the methods were the same, so much so that among the countless fictional characters based upon the Holmesian archetype, some have been crime-solvers (cf. Monk), yet others have been medical doctors (House is the best). Perhaps we shouldn’t model ourselves after the man, who was a single-minded addict and misanthrope, but when it comes to diagnosis — something we can’t escape in medicine — he knows whereof he speaks.

 

The diagnostic method

Holmes tells us in The Sign of Four that detection involves nothing more than three skills: observation, deduction, and knowledge. Let us consider what he means when faced with, for example, a complaint of chest pain.

Observation: we perceive a middle-aged male, alert and seated upright, rubbing at his sternum with a pained expression. His skin is slightly pale, his respiratory rate is slightly elevated, and he is hypertensive. He complains of “tight” 4/10 chest pain whenever he breathes. Upon auscultation we detect diffuse, bilateral, biphasic wheezing. We note a history of coronary artery disease, diabetes, and COPD.

Knowledge: Chest pain in adults indicates a high risk for acute coronary syndromes. Pallor, tachypnea, and hypertension are consistent with this diagnosis. Sharp, mild, pleuritic pain is not, nor is wheezing, all of which are more consistent with a primarily respiratory etiology. But we also know that MI often presents atypically, particularly in diabetics.

Deduction: Both cardiac (ACS) and respiratory (COPD exacerbation) diagnoses top our differential. An ECG and biomarkers are needed to further evolve the odds.

 

So what just happened? We observed using our medical assessment — the history, physical, and diagnostic tests — thus yielding a collection of facts and data. We took the set of background knowledge we already possessed, regarding pathophysiology, epidemiology, and hazard ratios, and used it to “fill in the blanks” and provide context to our assessment findings. Finally, we connected the dots together and used deduction to decide what we’re dealing with.

Holmes knew this method well. He might observe your tattered boots, and using knowledge he possessed of typical wear patterns in the various trades, deduce that you make your living as a longshoreman. Simplicity itself.

Why is this a useful model for diagnosis? Because it highlights the fact that these three skills are entirely distinct, though all quite essential. Observation requires skill with the physical exam, the ability to take a nuanced history, the acumen to interpret diagnostics — it’s simply the trait of being aware. (Holmes, succinctly: “Data, data, data! I can’t make bricks without clay.”) Knowledge is knowledge: it’s memorized facts, what you learn in school or from books, and it gives us the basis to understand the raw material we discover in our assessment. Finally, deduction is the mental capacity to analyze, discover patterns, weigh odds, use your imagination, and extract from the vast pool of observation and knowledge the particular pieces that are actually relevant. (Holmes: “… to recognize out of a number of facts which are incidental and which are vital.”)

 

The hidden danger

Here’s the rub: we’re almost too good at deduction. Humans are excellent at finding patterns in anything. If I leave you my tea-cup for long enough, you’ll undoubtedly find an image revealed in the leaves.

That’s good — but it’s an error. Because there’s not really any image in the tea leaves. But if you’re good at observing details, and have a strong imagination, you’ll still “deduce” many wonderful things from it. Call it apophenia: people want to connect the dots, even when there aren’t any. So we create connections that may be true, but are not always true. We develop stereotypes. Simplifications. False associations.

In medicine, we’re especially prone to this. Because we do know that the human body is interconnected, and that patterns are the rule rather than the exception. Indeed, a large part of developing experience and clinical judgment is increasing your catalog of mental connections. Crackles mean CHF. Irregular pulses mean A-fib. People with Foley catheters have UTIs. Homeless people are drunk. Toe pain is a nonsense complaint. We can’t avoid making the connections, because just like when Holmes examines your boots, those connections are essential to doing our job. But at the same time, we need to learn when to reign them in, or we enter an inescapable diagnostic tunnel after the first moments of patient contact.

It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.

A Scandal in Bohemia

What’s the secret? Knowledge.

Sure, we gather the pieces from our assessment, and we automatically start to connect them together. We can’t help that; patterns jump out at us, we’re natural pattern-finding machines. But using our knowledge, we can look past those simplistic, eye-catching patterns, because knowledge tells us something more subtle: what’s missing.

She’s all false positives. See, that’s the trouble with naturals. They don’t see what’s missing.

Lie to Me, “Moral Waiver”

Okay, Friday night, a “man down” call for a homeless guy on the sidewalk. You’re already thinking: drunk. And the initial observations confirm it: he rouses sluggishly, slurs his speech, and pushes you away as he rolls back over. But then you open the mental box that you filled with this sort of thing in your training, and you reflect: where’s the bottle? And this is a strange spot — it’s cold, wet, public and unsheltered. And come to think of it, is that a medical alert bracelet? We should probably check this guy out a little more. Maybe take his blood sugar, look for any trauma, shake him awake and ask some questions.

The initial pattern recognition is there, but you don’t have to be a slave to it, because you know what else to look for. Even if five clues say one thing, if we don’t see five others that ought to be there, that tells us something different. Pertinent negatives, they call ’em in the business.

Maybe there’s nothing else; maybe the drunk is just drunk. But we’re too smart to make that kind of assumption. Because we know that getting it right doesn’t just mean registering the hits — it means checking off the misses, too.

Holmes would expect no less.

 

 

Am I Normal? Finding the Baseline

When it comes to vital clinical skills that simply aren’t taught in EMT class, it’s hard to think of one more important, more frequently called upon, and less formally instilled than this: the ability to determine a patient’s medical baseline.

What’s that even mean? Simple enough. People call us because they have problems — specifically, new problems, or at least new complications of old problems. They don’t call us because of the stroke they had five years ago, or their existing stable angina, or because they still have dandruff. (Okay, sometimes they do, but then we ask why they really called.) So when you’re presented with the patient who has all of those things, the question is: what’s new?

Usually, of course, they tell you. “What’s going on?” “Oh, my stomach hurts.” Most days their stomach doesn’t hurt, today it does, they want to know why. Fair enough. But then you continue through your history and physical — does this hurt too? can you feel that? look here, please — and you find various other abnormalities. Are those new? If so, they may be important. If not, nobody cares. Nobody will thank you for performing a masterful assessment, stroking your beard, and announcing to the world: “I believe the patient has… cancer!” when it was diagnosed a year ago and the patient is already undergoing a planned course of treatment.

This was all much easier in the textbook. They spent quite a while teaching us what healthy people are like — their vital signs, their anatomy, their physiology — so that we’d recognize when someone deviated from that, and we could figure out why. And of course, that method works. As long as your patients are healthy. Unfortunately, healthy people don’t call 911 nearly as often as sick people. Forty years ago, maybe the majority of our patients were generally well individuals with acute problems — broken legs, allergic reactions, unexpected heart attacks — but nowadays, the bread and butter of EMS consists of treating acute exacerbations of chronic disorders, or new complications in the setting of multiple comorbidities.

So how do you figure out which irregularities are worth remarking upon, and which are unremarkable for the patient? Here are some tips.

 

1. Ask the Patient

When they’re able to help out, the patient is one of the best sources of information. Do you know how your blood pressure usually runs? Is your pulse normally a little slow? When did you get this bruise?

Patients with adequate memory and cognition are generally pretty good historians about their own bodies. Not necessarily the details — sometimes the endless litany of acronyms, tests, and diagnoses can blur together — but the personal stuff. They are intimately aware of the fact that they’re usually nauseous in the mornings, they’re told about their high BP whenever they visit the doctor, and they notice their abnormal pupil every time they look in the mirror. Patients with some cognitive impairment may be less able to help you out here, but as a rule, they should still be your first source — you should simply view their input with the appropriate amount of weight based on their perceived reliability. Of course, you should try to corroborate, and the best way is to…

 

2. Ask Someone Else

Most sick people, particularly those who aren’t 100% capable of taking care of themselves, have other people closely involved in their care. For those who live at home, these people are often family members or occasionally an aide or visiting nurse; for those living in a facility, it’s the nursing staff. (And for a patient being discharged from the hospital, it’s the doctor or nurse responsible for them.)

These people have spent ample amounts of time with the patient, so they “know” them — but moreover, they’re medically trained (or in the case of family, often have a sort of on-the-job medical familiarity of the patient’s conditions), so they know them medically. They not only have a reliably story to tell, they can often answer questions about the kind of medical signs you may be puzzled by. Oh yes, he’s got A-fib, his pulse is always like that. No, normally he’s alert and oriented, conversational, I don’t know what’s wrong with him now. Even friends or bystanders can sometimes help you out here — oh yes, Jeff has epilepsy, he takes medication for it, but he hasn’t seized like this in years.

This is the kind of information to gather before you leave a scene, because not only can it be important, you may be the only person who can obtain it. Once you show up at the hospital, if relevant history is missing from the clinical picture, the ED staff may try to make some calls and ask questions, but it’s much more difficult than if you did your job right to begin with.

This is also why it’s highly advisable, whenever time permits, to perform a reasonably full assessment prior to leaving the scene. That way when you find something striking, you can simply ask someone — is this normal? Nothing’s worse than taking an initial set of vital signs ten seconds after you start transporting, finding a blood pressure of 86/40, and wishing you’d done it five minutes earlier so you could’ve asked the nurse. (In fact, if you did this before leaving the floor on a discharge, they might just decide not to send the patient after all.)

One trick I’ve tried when I wasn’t smart enough to assess on scene is to simply call back. You’re bringing someone from a facility, and on the way, you find something funny. You’d love to know if it’s new or existing. Crack open the paperwork (or ask your dispatch) and find the phone number for the sending facility, punch it into your phone, ask for the floor or wing you took the patient from, and request the nurse who covered your patient. Then you can identify yourself and just inquire: “Hey, this dude’s got a blown pupil. Is he always like that?” This probably won’t work with most scene calls, unless you have a number for an emergency contact, but I suppose you can try to track someone down.

When nobody’s available to answer your questions, your best bet is simply to…

 

3. Consider the Context

As we often talk about, clinical decisions and diagnoses aren’t made from isolated findings. You have to look at the whole picture.

I love dialysis patients, because they’re like case studies in exercising clinical judgment. I have had regular dialysis patients who were at baseline non-verbal, marginally responsive, routinely hypo- or hypertensive, routinely tachy- or bradycardic, dyspneic, hemiparetic… pretty much anything you can imagine. Obviously if you know them you might have a better idea of their baseline, but again, with some of these people, I would not bat an eyelash to find them with a blood pressure of 80/70 on one day and 176/100 the next. Was either one an emergency? Not necessarily. It was probably something the dialysis staff and potentially their nephrologist would like to know about, but once again, it’s not helpful to anyone if you throw up your hands and announce that the person with kidney failure is sick. They know.

In any case, how do you figure out when their derangement is significant? Look elsewhere. Big problems have a big footprint. If the patient is communicative and reliable, how do they feel? Lousy? Fine? Weak, dizzy, nauseous? Pain in their chest, their head? Consider their history, look elsewhere in the body, and examine their medications. Assemble all the data you can, so that your findings are no longer a lonely, isolated result, but just one of many meaningful indicators.

To suggest that something might be important yet has no effects is to invite the question: if it’s not affecting anything, who cares? For instance, I once discharged a patient whose pulse was in the low 40s. No notation of this was found in her documentation, nor any obvious reason why she should be bradycardic. I eventually called back to her floor and her nurse confirmed that it was typical for her. But even if this hadn’t been possible, I would still have known the rest of her presentation: she was alert, oriented, mentating well, pleasantly conversational, and had a reasonable blood pressure and normal skin signs. She was experiencing no distress or acute complaints, and she was reliable enough that if she had been, she’d have been able to communicate her symptoms. So what were the chances that her bradycardia was something new, alarming, and indicative of a dangerous situation? Not very high.

The biggest challenge here is the patient with so many other comorbidities that they become difficult to clinically assess. If they can’t communicate well (or can’t communicate in your language), and at their baseline they have a wide variety of derangements, it can become difficult to wade through everything and isolate new badness from the tangle of typical badness. Use your noggin and do your best.

Finally, your fallback is always…

 

4. Get to the Right Hospital

Barring anything else, even in the most baffling of situations, most clinical mazes can be untangled if you transport the patient to their usual hospital.

By this I mean wherever they’re typically followed. It may or may not be their requested destination, although it usually is; in any case it’s where they get most of their care (often a nearby community hospital, although sometimes it may be more distant). Some providers give little consideration to these requests, preferring to push for transport to the closest facility or specialized points of entry, but this isn’t just a matter of where the patient likes the meatloaf and the nurses. If you show up with the non-communicative patient with a bizarre presentation and minimal available history, at a hospital that’s never seen them before, they are going to be just as baffled as you are. Eventually they may be able to sort most of it out, but only after substantial time and potentially invasive and unnecessary testing — not exactly the most timely and appropriate care. Remember that although one hospital can usually request records from another, it’s often a cumbersome process involving phone calls and faxed charts, and will never be as comprehensive as what the original facility has access to. (The exception may be hospitals that share an affiliation, which may use the same computer system and hence can mutually access shared records.)

Extremely complex medical histories should go to their customary hospital whenever possible. In some cases, the situation may be so unique that an outside facility won’t even want to touch it — your patient will simply be stabilized and transferred to their normal hospital. This is particularly true when there’s been a recent procedure, devices like an LVAD are in place, or the patient has a rare medical disorder; these patients really may need to be attended to by the specific physician who knows their case, and that kind of familiarity can’t be transmitted by fax.

 

Long story short, this whole process can be challenging, but managing it is one of the basic skills we need to hone if we’re working in the field. Any monkey can point to the ways that someone differs from textbook normality; it takes a discerning eye to pick out the changes that are relevant to our business of emergency medicine.

Your High Horse

What happened to kneeling?

People have problems, so they call the ambulance. We arrive and find them — mostly — seated in a chair, or lying in a bed, or perhaps down on the ground. Then we kneel beside them and introduce ourselves. We ask questions, put our hands on them, give medicines, and so on down that clinical flow you learned in school.

Here is what we don’t do: stand six feet away, look down at the patient (and maybe, maybe deign to bend over a little, with our hands on our thighs like we’re admiring a gregarious puppy), and shout in their direction. “Do you want to go to the hospital?” This is not yodeling practice. This is caregiving.

When did we stop kneeling? More and more, this practice seems to be spreading, and it’s reached the point where I can hardly remember the last time I saw one of us kneel beside a patient. Occasionally somebody will kneel to take vitals, but the provider actually speaking and interacting with the sick person still towers over them like a cop chalking off a body.

Yes, yes, I get it. Your knees are bad. I’ve been there. And your back, it’s stiff. You’re not 21 anymore, you can’t go kneeling willy-nilly. Sure.

But we’re not talking about an Olympic sport here, okay? We’re talking about kneeling, at least for a moment, in whatever manner you can successfully perform. At the very, very least, sit down on something so you’re level with the patient. Park your butt beside them on the sofa or pull up a chair.

It’s about patient comfort, because they want to feel like they’re engaging with a fellow human, not yelling up at Rapunzel’s tower. But it’s also about the dynamic it creates between you. As a novice provider, when I first read Thom Dick write about humility, I didn’t understand. But as time passed, it made more and more sense to me (something that happens suspiciously often with Thom’s stuff). Body language says something, not just to others, but to yourself.

When you kneel, you’re saying: I’m here to help. I’m here to serve you. We don’t kneel very much anymore, not in the modern Western world, but we understand instinctively why one would kneel before a king. It’s not in spite of the effort it takes you to get down there, it’s because of it: by making yourself uncomfortable, you’re demonstrating a willingness to put someone else’s needs before your own.

It’s not saying that they’re your master, and you’re not making them the boss of anything. They’re not making you kneel, which is all the difference: it’s a gift, freely given. You’re acknowledging that the patient is important. More prosaically, it’s very much like the relationship that the cashier at Wal-Mart is supposed to have with you (at least in theory). If you met him on his day off, he might cut you off in traffic, flip you the finger, and drive away cackling. But while you buy batteries, at least, it’s his job to help you out. If he’s lucky, he enjoys doing that; if he’s not, he feels forced into it because he wants to keep his paycheck. We’re in a different boat, though, because our obligation doesn’t come from a boss looking over our shoulder. It comes from the fact that we accepted a duty (perhaps sacred, perhaps mundane, but a duty either way) — that when someone calls 911 and asks for our help, we’ll come and serve them. That makes us servants, and not in a bad way.

Something different happens when you refuse to lower yourself before a patient. It tells everyone in the room, including the patient and especially including yourself, that although you’re here, and although you might perform the clinically-indicated medical treatment, you’re not putting yourself out at all. Drive-by care is all you’re willing to offer. It’s like telling the patient: “Just to be clear, we were in the area anyway, and I thought you might have some snacks.”

I have great respect for police, and we work alongside them often. But their business is very different from ours, and it highlights the dangers in conflating the role of EMS with that of public safety. The job of a caregiver is to serve. The job of a cop is to enforce. It means they have to elevate themselves — you can’t exert authority unless you’re coming from a place of some kind of superiority (legal, moral, even physical). It means they have to judge. I don’t know if they enjoy it, and I do know that it’s highly necessary. But it takes a different kind of person, or at least a different kind of thinking, to judge people than it takes to serve them. Try to imagine a cop kneeling, or helping to wipe Mrs. Smith’s bottom. Now imagine yourself wearing aviators, crossing your arms and leaning against the wall while you bark at her, and understand that it’s just as misplaced.

What’s funny is that when you accept this “lesser” role, you can find an awful lot of meaning in it, because it’s a privileged place too. The privilege isn’t something you exert over others: rather, it’s freely granted to you by the patient. When they see that you’re here to help them, they give you permission to enter their home, to touch their body, to ask them the most intimate questions. This is essential, because you need that access to do your job (and it’s why I believe that mixing EMS and law enforcement would mean a major blow to our ability to treat people). But it’s still a gift. And I think that’s worth something. Even sore knees.

A Million and One Towelplications

Yes. Towels, sir. I said towels.

What’s the big deal with towels? Well, you’ve got them around, first of all. Or you ought to. A decent stock of linen really amounts to essentially supplies for an ambulance, and yes, I maintain that even if you do use the crinkly disposable paper sheets. Blankets for sure, sheets if you use ‘em, and towels. Lots of towels.

Towels are the duct tape of padding-related conundrums. If you can’t do it with a towel, it doesn’t need doing. Other than stopping bleeding, checking your oil, and (I suppose) actual cleaning, most applications involve using them as some sort of padding. But to become a towel samurai, you’ll first need to learn the three basic towel forms: Rolls, pads, and snakes. (Towel supply is a little limited at this exact hour, so I’ve substituted an old bath towel, which I’ll thank you not to abuse.)

 

The Towelbox

Pads are simply towels folded flat, into squares or rectangles of the desired size, like a napkin. Good for basic flat padding purposes — just make sure you fold intelligently to obtain the size and thickness you need (and don’t be afraid to stack multiple towels together).

 

Rolls, on the other hand, are constructed by folding long rectangular pads and then rolling them into fat, tight little cigars, like toilet paper. Great for makeshift pillows, extra-thick padding, and anything requiring bulky structure or space-filling.

 

Finally, snakes are towels unfolded to their full length and then twisted (or folded very thin) to make long noodles. You can even tie them end-to-end to make ropes. Great for “lengthwise” padding, makeshift towlines, wrapping around stuff, etc.

Got it? Good. Now, here’s a few uses for the things beyond just cleaning up your messes.

 

Padding Voids

You were taught to do this in school, and then you promptly stopped bothering. Shame on you. It takes practice to get good at it, but if you do, you can seriously reduce the physical abuse you’re inflicting on your patients by backboarding them.

Make small rolls to fill the lumbar void, and rectangular pads for thick spaces like between the legs. Blankets may be needed for particularly large areas, which is fine — blankets are just towels on steroids, after all.

Take the time to pad in a similar fashion when applying splints, particularly box-style splints, and you can substantially increase their effectiveness. Works great for scoop stretchers too. Patient with a hip fracture on the ground or in a bed? Scoop them up, and generously pad between and over their legs. Once you secure the straps there should be nowhere to move, and you’ve turned the device into a secure, large-scale lower-body splint with essentially no movement of the limb. Not bad.

 

Silencing Equipment

We talked about this before — particularly when it comes to backboards, which have a habit of banging around in their enclosures, a towel roll (or if the gap is slim, a thick pad) can be a quick fix to muffle the noise a little.

 

Head Immobilization

Most services nowadays have gone over to commercial head blocks or headbeds; the days of sandbags (or liters of saline) are sadly over. However, there are still places that use primarily towel rolls, and even if you carry commercial blocks they make a great backup — and we always need backups. Frankly, I think good towel rolls work better than most other methods, too; they compress and mold against the head, making them both comfortable and secure.

Stack together two or three large towels, folded into long rectangles, then roll them together tightly into a thick cylinder about the same length and not much thinner than a human head. Take some tape (I like 2″ cloth tape for this) and tape a couple rings to hold it together — a loop near both ends seems to yield better padding than looping the middle. Make a second roll just like it, and you’ve got headblocks! (The roll depicted is probably a little longer than necessary.)

Secure them alongside the patient’s head and tape the same as you would commercial blocks. Just make sure they’re fat enough to provide real support; a single rolled towel, for instance, never seems like enough bulk.

 

Ghetto Collars

So you sized the patient, you reached for a no-neck C-collar, and it’s too small. Oh, it’s not a matter of neck length; they are indeed neckless. Rather, it’s a question of girth. They’re just too big for the collar to reach around. And sadly, although most rigid cervical collars come in a variety of heights, there are usually no options to size for diameter (pediatric collars may be smaller, but there’s rarely any “bigger” size available). What to do?

Try a towel snake. Using a long towel (or two), twist it into a thick rope and wrap it around the patient’s neck like a scarf. Don’t choke them, but wrap it snugly; most towels seem long enough to circle a typical neck with plenty of overlap, which I leave in the front as a chin support. Slap a little tape across the overlap to more or less secure it, and there you have it — a good-faith attempt at cervical immobilization, not as effective as a rigid collar but far better than nothing. (You can always sit there holding manual immobilization too, I suppose. But remember that the collar is mostly a reminder, and the blocks and straps are doing the majority of the work to actually limit motion.)

 

We could go on forever about towels, and I don’t even know most of the tricks; this is the sort of thing you figure out gradually over the course of a long career. (Although Christopher Watford did turn us onto towel animals as popularized by Carnival Cruise Lines, and if you can master those you’ll be a big hit at parties.) Thom Dick has a stellar collection of ideas that he writes about in his columns. We’ll probably do a sequel to this eventually, but in the mean time — what are your favorite uses for towels?