Differential Diagnosis - How do I study for it?

[WannebeParamedic]

Hi team,

I am waiting for training to begin so at the moment I am technically not even a student. However, I am fascinated by Paramedicine and have been studying it in my spare time. I understand general anatomy and physiology terms/directions as well as some of the anatomy of the cardiovascular, respiratory, and some of the nervous system. I also know a fair bit about the gastrointestinal system. I have learned some basic trauma.

I am trying to practice applying OPQRST and SAMPLE but really don't know how to set things up. I was going to make queue cards for a friend and then ask them questions but I don't really know how the "game" would work.

It is possible I just don't know enough at the moment so I picked what I would have thought would be an easy example - snakebites. How would a paramedic approach a snakebite patient?

I picked snakebite purely out of personal interest. And I am using snakes from the US in my scenario - Pit Vipers and Coral Snakes.

My guess is that:
1. You meet the patient and introduce yourself and ask some identifying features about the snake.
2. You ask OPQRST
3. You do SAMPLE (perhaps signs and symptoms as you are doing OPQRST)

Does anyone have any advice?

Would you recommend that I focus on another medical/trauma subject to practice OPQRST and SAMPLE?

 

[mgr22]

I don't know where you are, whether you're an EMT or what else you've done, but here's some generic advice:

- Ditch the snakebite scenario for now. It happens, but it's unlikely for most of us.
- I see you're 35. That means you already have lots of life experience. You should use that to help get an initial impression of patients -- e.g., safe or dangerous; conversant or not; cooperative or not; sick, injured, both, or neither.
- Start a conversation with the patient and check a pulse while you observe mental status and respiratory effort. Don't bother counting anything; notice if the pulse is weak or strong, fast or slow, and/or regular or irregular. Know something about what those findings might mean.
- Try to find out what you'd want to know if the patient were a friend or family and you weren't medically trained -- e.g., "What's going on?", "Where does it hurt?", "How long has it been that way?", etc. So much of EMS is communication.
- If you do have any medical training, get whatever history you can. Look for meds and conditions you're familiar with. Those are clues.

At some point you'll need to know what OPQRST and SAMPLE mean if you want to pass tests. In the beginning, though, I think it's more important for a middle-aged learner to make sense of the assessment process, rather than to simply memorize the steps.

Being good at assessing patients is less about measuring things and more about understanding things. You should never stop getting better at that. You can begin on Day One.

 

[akflightmedic]

Read the above post. Read it again. Follow the words of wisdom.

 

[NomadicMedic]

There’s an old adage, “the patient will tell you everything you need to know, you just need to know what to ask.“

once you start to study paramedicine, you will become more familiar with signs and symptoms of specific illness and injuries. As you gain knowledge and experience, you will learn what questions to ask and how to formulate a differential diagnosis.

Here’s a simple scenario . You're dispatched to a 30 year old male, not acting appropriately. His girlfriend says he is difficult to arouse, when he talks he’s not making much sense and he’s slurring his words.

Now, from that initial description, you should start thinking about causes of altered mental status. As you progress through your assessment and diagnostics, you start to narrow things down and rule things out.

For example. Hypoglycemia? Check a blood sugar, it’s 126. That rules out a blood sugar issue.

intoxication? He doesn’t smell like alcohol. There’s no alcohol in the house. His girlfriend says that he never drinks because both of his parents were alcoholics and he can’t stand alcohol.

Did he suffer some type of head trauma? Girlfriend said he was out riding his BMX bike with some buddies earlier and took a spill, she doesn’t know if he was wearing a helmet. He came home and said he was gonna sit on the couch because he didn’t feel quite right and that maybe he would take a nap.

Ding ding! Does he have some sort of head injury? I don’t know. But if I had to shake the magic eight ball, signs would point to yes. It makes sense, it fits the situation.

Now, that’s probably the simplest scenario I could give you, but do you see how you start to think about differential diagnosis? What could be wrong. What is the most likely cause. Let’s go down the list and see if we can figure out what’s wrong with this guy and treat them appropriately.

that is the basic process for developing a differential diagnosis. Ask the right questions. Be a good detective.

 

[johnrsemt]

Following up on mgr22:
As you talk to the patient (is he/she answering appropriately and looking and tracking you: "Hi I am John, what is your name {do they answer correctly? do they look at you? do they respond?}), and are checking the pulse, (again not counting, but checking for strength, and rapid/slow), feel for skin temperature (cool, cold, warm, hot: against the room or outside temperature), look at the skin (pale, pink, bluish, grey).
This 15-30 second check will tell you a lot of things: they are conscious and alert: they are answering appropriately, skin temp matches the room temp. HR is strong, weak, regular, or irregular

 

[NomadicMedic]

The best scenario to practice OPQRST and taking an AMPLE history is chest discomfort.

 

[WannebeParamedic]

I don't know where you are, whether you're an EMT or what else you've done...

No formal training, not an EMT or anything. I am going to begin training in a couple of months. I have been self learning.

- Start a conversation with the patient and check a pulse while you observe mental status and respiratory effort. Don't bother counting anything; notice if the pulse is weak or strong, fast or slow, and/or regular or irregular. Know something about what those findings might mean.

Are you saying at this stage I am doing GCS (for mental status?), and listening to breathing via a stethoscope for the respiratory effort?

Checking pulse seems straight forward. Thanks for that.

What I take from this: Focus my study on the respiratory system and cardiovascular system. This will take weeks/months. Can I learn to understand the process before then?

- Try to find out what you'd want to know if the patient were a friend or family and you weren't medically trained -- e.g., "What's going on?", "Where does it hurt?", "How long has it been that way?", etc. So much of EMS is communication.

This is the conversation you would start while doing the GCS and checking respiratory effort right?

- If you do have any medical training, get whatever history you can. Look for meds and conditions you're familiar with. Those are clues.

I am self learning at the moment while I await formal training. Besides Trauma and anatomy, I do not yet have a good knowledge of medical conditions. I am familiar with:

Non-cardiogenic and cardiogenic pulmonary edema
Snakebites from North America (Pit Viper and Coral Snakes)
Diseases/conditions of the gastrointestinal system.

I obviously know about hypertension/tachycardia/bradycardia/different kinds of shock.

Actually that is really it... Most of what I have been learning until now is about Trauma and anatomy (but not the medical illnesses).

I think it's more important for a middle-aged learner to make sense of the assessment process, rather than to simply memorize the steps.

Yea, that is where I am having trouble. I want to practice the assessment/make sense of the process. I learned about snakebites of North America because it only took about an hour to memorise and the goal is to make sense of the assessment process. Studying cardiac and respiratory medical conditions will take weeks (which I am going to do) but surely I can start understanding the assessment process now using snakebites as an example?

As you gain knowledge and experience, you will learn what questions to ask and how to formulate a differential diagnosis.

This is where I get confused because I have learned and understand everything about North American snakebites and don't know how to do a differential diagnoses - other than to ask the patient about the snakes pupils, head shape, presence/absence of a rattle, and the colour of the snake.

If the snakebite victim did not see the snake or can't remember anything about the snake what do I do?

My best guess is that the only real thing to do is to determine the severity of the snakebite and just treat. Actually figuring out what toxin/snake it was is irrelevant to a paramedic/EMT?

My concern is that if I can't make sense of the assessment process for something as simple as a snakebite, it is hard to imagine me making sense of the process for the more complicated cardiovascular and respiratory diseases.

Thank you to everyone for your help and advice. I really appreciate it.

The best scenario to practice OPQRST and taking an AMPLE history is chest discomfort.

@NomadicMedic isn't chest discomfort going to involve mastering the cardiovascular and respiratory system as well as all associated medical conditions? I am going to do this, and I understand this is a big part of what a paramedic does. But effectively it means I won't be able to practice anything for months as there is a lot to learn on the cardiovascular and respiratory system.

Surely there is a way to practice using medical conditions of the gastrointestinal system or snakebites? I understand these will not be common issues that paramedics have to deal with, but for the purposes of practicing patient assessments and history, I need to use medical conditions I am already familiar with or that I can learn relatively quickly. I will then be able to practice it while embarking on the very long journey of mastering the cardiovascular and pulmonary system and associated medical conditions.

 

[mgr22]

WannabeParamedic, forget about snakebites for now. Seriously. Get into an EMT course asap. That will lay out a curriculum of basics to follow. All paramedics start that way.

I understand and support your enthusiasm, but in the absence of any EMS training or experience, self-study shouldn't be your primary vehicle. You need the guidance and structure of a formal program to help learn priorities, procedures, and risks. Give yourself a chance to absorb that.

 

[E tank]

Learning without thought is labor lost; thought without learning is perilous. - Confucius

Learned that watching a cooking show last nite...

 

[WannebeParamedic]

The course has not started yet so there is no way to get on to it sooner. It starts in May.

Surely it is better to do some study now before the course starts. I have actually been able to find a lot of course work online already - there are youtube playlists that cover EMT training (for the US) which are surely not too different from what I will need to know. The course I am doing will be mostly by distance learning.

So I have the formal structure. I understand the priorities, but I would like to get a head start.

The only real difference between me being on the formal course and what I am doing right now is that I cannot email and instructor and ask for clarification on how to practice primary assessments and patient history taking. I am literally working off the material that makes up an EMT course.

Surely there is something to gain by practicing and learning new things now? I learned about the different types of body tissues (epithelial, connective, nervous, muscle) and the different types within those types (e.g. there is areolar, adipose, fibrous, cartilage, bone, blood, hemopoetic connective tissue). Why would this not be of benefit to me?

I can't bring the training forward - believe me, I want to. I have to wait until May. I will be working a fulltime job while doing the course so the more of a head start I get, the better.

Thanks for your feedback.

 

[Jim37F]

If you're not already an EMT or Paramedic, starting with Differential Diagnosis is a pretty advanced place. All that is is putting together all the information the patient is telling you and what you're seeing with your assessment combined with what you've learned in class to figure out what is likely going on. It's kinda hard to do that if you haven't actually gone to the class yet to learn anything.

Any proper EMT course is going to assume you know nothing going in and teach to that.

It's great you want to study and learn. That is highly recommended. But I'd recommend starting with the basics. If you haven't already, CPR for Health Care Providers is a great start (and may be a prerequisite for your upcoming class)

Also start with basic Anatomy and Physiology. What the different organs are, where they're located, what they do. How they work together in different organ systems.

What are normal vital signs for different age groups?

There's a somewhat simplistic saying, "Blood goes round and round, air goes in and out, any deviation from that is bad". Simplistic yes, buy you do need to know the anatomy of how the blood goes round and round and air goes in and out. You should be able to talk about the different chambers of the heart, the names of the valves between them, the path blood flows through the heart and lungs in order, as well as the airway structures in the upper and lower airways and how air goes from the mouth and nose down to where it meets the blood.

EMT Basic medications include Oxygen, Oral Glucose, Activated Charcoal. EMTs assist with Epi Pens, Nitroglycerin, Albuterol, Aspirin... what are these different medications? What are their indications and contraindications? What do they actually do in the body?

If those are the medications, what does that tell you about what medical conditions they talk about in EMT class? Heart issues like Angina and MI (what is the difference between those two?) for Aspirin and Nitro, Asthma, allergic reactions, Diabetes, what's the difference between Type I and Type II?

Bandaging, splinting, DCAP-BTLS...

I could go on, but you need to learn the basics before you can really begin to form any differential diagnosis...

Find out what book your class is going to use, and get a copy now. Read that. Re read it. That'll be your best resource for self study and studying ahead... because that's going to be the exact same info they use to teach in the class.

 

[WannebeParamedic]

If you haven't already, CPR for Health Care Providers is a great start (and may be a prerequisite for your upcoming class)

Thanks for your advice, I have completed my first aid requirements for the course.

Also start with basic Anatomy and Physiology. What the different organs are, where they're located, what they do. How they work together in different organ systems.

I have learned this already - still a bit to go with the more advanced aspects of cardiovascular and respiratory stuff.

You should be able to talk about the different chambers of the heart, the names of the valves between them, the path blood flows through the heart and lungs in order, as well as the airway structures in the upper and lower airways and how air goes from the mouth and nose down to where it meets the blood.

I learned this. I can name the two atria and ventricles of the heart, the two layers of the pericardium, the mediastinum, the pulmonary vein, pulmonary artery, superior and inferior vena cava, tricuspid valve, pulmonary valve, mitral valve, aortic valve, as well as the superior aorta and then aortic arch. I have a good understanding of perfusion and how blood enters the heart and then travels through the pulmonary artery to the lungs where gas exchange occurs through the alveoli and the capillary beds. The now oxygenated blood then goes back to the heart via the pulmonary vein etc etc.

I am familiar with the upper airway (nosopharanx, oropharanx, larygeopharanx, larynx, epiglottis, trachea) and the lower airway (bronchi, broncholis, alveoli).

I have a good under standing of the different parts of the lungs (superiod/middle/inferior lobes on the right hand side and superior and inferior lobes on the left hand side) as well as the horizontal fissure and the oblique fissue etc etc.

All of this is from memory and I could explain it all in a lot more depth.

I understand stroke volume, cardiac output, preload, afterload etc etc.

I have an understanding of all the anatomy and physiology required to understand hypovolemic shock, cardiogenic shock, abstructive shock, distributive shock etc etc

I'm not trying to show off, I am just trying to show that I do understand the basics of what an EMT/Paramedic needs to know.

What are normal vital signs for different age groups?

I don't know this. That is great! I will go and learn it.

EMT Basic medications include Oxygen, Oral Glucose, Activated Charcoal. EMTs assist with Epi Pens, Nitroglycerin, Albuterol, Aspirin... what are these different medications? What are their indications and contraindications? What do they actually do in the body?

I have been learning about the medications that I would be allowed to administer already. I learn one a day.

If you're not already an EMT or Paramedic, starting with Differential Diagnosis is a pretty advanced place.

It seems like a really good training aid to me. As I learn about medical conditions it seems like a valuable study tool.

This part is still confusing me as I have mastered both Gastrointestinal medical knowledge and snakebite knowledge. How can differential diagnoses be more advanced that you need to know more than what a paramedic would know? I specifically chose snakebites and gastrointestinal medical knowledge because they are not as they are easier to learn than the other stuff so I assumed that I would be ready to start practicing diagnosis or something like the OPQRST and SAMPLE for medical issues specific to these two areas.

I don't mind if I don't need to understand snakebites (we don't even have snakes where I am from). I just want to start practicing OPQRST and SAMPLE while I continue to learn the more advances cardiovascular, pulmonary and nervous system stuff. By the time I have mastered the cardio/pulmonary/nervous system medical knowledge, I want to be well practiced with primary assessments and patient history.

 

[VentMonkey]

“Black and yellow kill a fellow. Red and black, venom lack.” //shrugs// All else seems rhetorical at this point.

Re: pit vipers—don’t tourniquet the arm, keep it somewhat immobile, remove jewelry etc. For the love of God, don’t suck anything out of the patient. Oh, and don’t take the rattler with you to the E.D., cowboy.

I’m sure you’ll do ok. In fact, some might say you’re going a bit overkill on the knowledge for an EMT-B course, but good on you.

The advice given here by several posters should not be taken with a grain of salt. That is all.

 

[WannebeParamedic]

The advice given here by several posters should not be taken with a grain of salt. That is all.

Yea, I am absolutely grateful for the advice and I have taken notes of what people have told me.

Unfortunately, I have already memorised the snakebite stuff so it is too late to not learn it.

In all honesty, I actually found the snakebit stuff interesting. Even though it will never be of use to me as I don't live in North America.

some might say you’re going a bit overkill on the knowledge for an EMT-B course, but good on you.

I am interested in the Paramedic pathway which is a three year degree (after you complete a 30 week course and then a one year diploma).

Re: pit vipers—don’t tourniquet the arm, keep it somewhat immobile, remove jewelry etc. For the love of God, don’t suck anything out of the patient. Oh, and don’t take the rattler with you to the E.D., cowboy.

Interestingly, there seemed to be a lot more information on treating Pit Viper patients. I was left with the impression that American Paramedics are not given any prior information about Coral snake bites other than the "red on yellow, kill a fellow. Red on black, venom lack" quote and that coral snakes have small fangs that can only really fit over fingers/toes etc etc. There wasn't any guidance on mild/moderate/severe envenomation or treatment guidance. Would you know where I can learn more about this from a source for Paramedics?

Just my personal interest.

Find out what book your class is going to use, and get a copy now. Read that. Re read it. That'll be your best resource for self study and studying ahead... because that's going to be the exact same info they use to teach in the class.

I have already asked for reading material but the course uses its own stuff that cannot be given out until I start the course for some legal/copyright/propriety etc etc reason.

 

[luke_31]

It’s great that you’re trying to learn everything before the course starts but a lot of the questions you’re asking now are going to be covered by your instructor once the course starts. Personally I’d stick with the A&P, and maybe research pathophysiology before the course starts. Understanding what a disease is doing to the body will help make sense out of a lot of what we do. Differential diagnosis isn’t something that is just studied on its own. It’s really a cumulation of everything that you’ve learned in emergency medicine as you’re taking what they are complaining of and going “ok now what conditions or diseases will cause these complaints”. You’re then going to treat them based on the tools you have at your disposal to help steer you down the most likely path and treat based of the patient’s condition and what is likely to kill them immediately or cause permanent harm. That’s a rough explanation of differential diagnosis. It’s also something that you’re not going to learn by reading a book. The basic tools to do it are in the book, but true understanding and mastery is done when you’re in the field seeing patients.

 

[WannebeParamedic]

Okay, I suspect that I am confusing what I am trying to achieve with differential diagnosis.

Really I am just trying to make a game that I can use to help me study medical conditions and get used to asking OPQRST and SAMPLE questions.

I understand from responses so far that once I become a Paramedic/EMT I will may not actually ask the OPQRST and SAMPLE questions in order.

Does it not seem an effective way to study by giving a friend a set of Q cards and then playing a game where I try and narrow down what is wrong with them (the medical condition on the Q card)?

Personally I’d stick with the A&P, and maybe research pathophysiology before the course starts.

I am unsure about this because how can I stick to learning something I have already learned? For example, I can tell you how food is chewed in the oral cavity and your salivary glands release salivary amylase which begins to break down carbohydrates. As you swallow the food (the "bolus") it goes down your pharanx and then esophogus (via peristalsis) through the cardiac sphincter and into the stomach. The stomach releases gastrin that stimulates the release of Hydrochloric acid and intrinsic factor (helps with the absorption of B12). Pepsinogen is also released and the hydrochloric acid causes it to become pepsin which helps in the breakdown of proteins. The food begins to by digested and becomes chyme. The chyme then goes through the pyloris sphincter into the duodenum - the first part of the small intestine. Bile, which is released from the liver and stored in the gall bladder is released and it emulsifies the fats in the chyme as well as diluting the acid. The next part is the gugenum where the majority of the absorption takes place. The surface is covered in villa which increases the surface area to aid absorption. From there the food continues to the illeum and then through the illeuocecum sphincter into the cecum and then the acsending colon, transverse colon, descending colon, sigmoid colon, rectum, anal cavity, and then out through the anus.

I can talk to you about the murphy sign or the cullen sign etc etc

Or I can discuss the upper/lower left/right quadrants of the abdomen.

I know about appendicitis, pancreatitis, stump appendicitis, stomach ulcers, hypermotility etc etc

So I get that I should learn anatomy and physiology - but I already have. I am beyond that. I will of course need to go over what I have learned periodically - and I will.

Again, I am not trying to show off here, I am just trying to show that I am already beyond the "learn the anatomy and physiology" part of my learning journey. I have learned it except for the more advanced cardiovascular, respiratory, and nervous system. I will continue to learn this but I also have time to learn about the medical conditions.

Even with the cardiovascular/respiratory/nervous sytem subjects I have still learned a lot. I can still discuss neurons, and myelin sheaths, axons, dendrites, soma, CNZ, PNS, Sympathetic, Parasympathetic, autonomic etc.

I could have a conversation with someone about ventilation, respiration (internal and external). I have previously demonstrated that I have a reasonable understanding of the anatomy of the heart.

How can it be that there is absolutely no value whatsoever in learning about medical conditions before the course starts? In order to learn about medical conditions, I am trying to find a way to come up with a Q card type of game. I thought of it as "Differential Diagnosis". Maybe that is not what it is.

I will begin studying the pathophysiology stuff now.

To put it another way, I have come to the part of my learning journey where it is time to learn about medical conditions. Does anyone have any suggestions or strategies for memorising them if the Q card/differential diagnosis idea is not going to work?

 

[akflightmedic]

Feeling a long hose job coming on....almost Brown-esque. The spellings and syntax.

But yeh, good on you for all these questions. You are going to be sorely disappointed when you start EMT school.

 

[WannebeParamedic]

Feeling a long hose job coming on....almost Brown-esque. The spellings and syntax.

Didn't quite understand? You mean my spelling was bad? I am sure it will improve over time. I typed my posts out quickly.

Also, what is a long hose job?

You are going to be sorely disappointed when you start EMT school.

Why do you think so?

 

[NomadicMedic]

Smells very Brown-esque to me as well.

 

[WannebeParamedic]

what does Brown-esque mean?