How do doctors diagnose us? 

    What methods, tools, heuristics and knowledge helps most in giving them this scary knowledge of disease? Well - here's an introductory glimpse into diagnostics. I will introduce some baseline concepts, tools and steps within the diagnostic process. 

     PLEASE NOTE: I am not a doctor, nor a nurse or a proper medical practitioner. I've no formal medical training outside of a first aid certificate and my own research - and my mom's old nursing experience. Although I plan to go to med-school, I am nowhere near the level of knowledge of a proper practitioner. That's to say: take this blog with a grain of salt, and avoid HouseMD syndrome as I like to call it - seeing rare conditions before common colds or diseases. Common is common - and while I do encourage pursuing and understanding your own health, especially when you suspect something is wrong, suspicion is not diagnosis - and we should consult professionals before jumping to heavy conclusions. Note that there are always exceptions to this - I just say it as a general rule of thumb. Now that my big disclaimer's out of the way - here's how diagnoses are formed! 

 

     Part 1: Evidence

   As per anything scientific - we need evidence to support our hypothesis. Diagnosing someone is much adjacent to the scientific method - we come up with a hypothesis, test it, and come up with a new answer based on the results. But evidence is complex - especially when dealing with a multitude of variables. Therefore, evidence is divided and nuance in medicine - there are many approaches to finding the same result. However, much like in a math equation - patterns form, and procedural evidence, treatments and answers can follow in a similar equation. 

1.1: Evidence - Signs vs Symptoms

   >Signs are objective, easily measured pieces of evidence. These are things a medical professional or their technology may observe - like measuring a pulse, blood pressure, or listening via a stethoscope. Not every disease has easily determinable signs (mental health is an easy example), which is why signs aren't the sole piece of evidence in a diagnosis. Yes - facts matter, but so do opinions.

   >Symptoms are subjective, patient-recorded pieces of evidence. These tend to be less measurable - and are the second half to a diagnosis. Example: "I feel tired", "I have a headache", "I feel pain", or "I feel nauseous" - these are difficult things to scientifically measure, but can still be diagnostically relevant. Some symptoms can be slightly more measurable (like when doctors ask you to scale it 1-10), but are generally subjective regardless. 

   >Key takeaway: Signs and symptoms blend together to form a diagnosis when they can - but not always. Some diseases have more signs than symptoms, and some have more symptoms than signs - so the best diagnosis tends to blend both observable, objective information with subjective symptomatic information. 

1.2: Evidence - Acute vs Chronic vs Subacute

    >Acute conditions or symptoms tend to be more common - think of a broken bone or an anxiety attack. Acute conditions tend to be milder and only last a few days, hours or minutes. While acute symptoms can be results of chronic conditions - they can also be unrelated. Ex: Colds, broken bones, concussions, manic episodes, etc. Anything easily explained by a cause (like a concussion caused by getting hit in the head, a manic episode as a result of bipolar 1) can be considered acute symptoms - either of a simple disease or as a predictable result of another condition.

   >Chronic conditions take place over a longer period of time - persisting over months, years or even life-long. High blood pressure, diabetes, cancer, chronic pain, developmental disorders, etc. Chronic conditions tend to be more severe than acute ones - and tend to require careful management or lifestyle choices. 

   >Subacute conditions inhabit that weird grey area between acute and chronic - they're not quite as long or severe as chronic conditions, but simultaneously aren't just day-long affairs like a cold or allergies can be. For our purposes - you don't need to know much about this, but in the future it may be useful.

   >Key takeaway: Acute and chronic conditions can be worlds apart from another. A headache which persists for an hour is worlds different from one which persists for a week, and even more different than one which persists for a year. 

1.3: Evidence - Red Flags

  >These symptoms or signs can differentiate mild, acute conditions from more severe, fatal or chronic ones. Red flags can be acute symptoms or happenings - and tend to be the most severe of them. Ex: Heart Attack, Random weight loss, sudden weakness, paralysis, etc. - while these are acute, they are great cause for concern - especially when they are unexplained by existing history or conditions. 

    Part 2: Diagnostic Process

    Now that we have our evidence curated and understand the nuance within it - we can start throwing ideas around. There are many keys to getting this right - and is what makes a difference between good and bad, or experienced and inexperienced. 

2.1: Diagnostic Process - Common Pitfalls & Mistakes

    Before I get into this process - we should be aware of our own, human errors. Everyone makes these mistakes - the difference is contextual. The best analysis is from one who understands their own biases and human nature - therefore, building an understanding of the common heuristics and shortcuts which our brain may take is helpful to avoid excessive bias. 

• Premature Closure

       >The premature shooting down or closure of the diagnostic process. Think of when you're running late to something - would you rather take the time to untie and tie your shoes at the door, or just jam your foot in enough that they work or slip on? Premature closure is much like that foot-jamming - we skip a step in order to streamline our personal experience. Although helpful in daily life, this heuristic can stop us from accurate scientific analysis and diagnosis - shooting down severe necrosis as "flesh wounds" or brain damage as a "light concussion" impedes proper diagnosis. The counter to this is being open minded and patient with the possibilities - separating the human short-cut-taking instinct within you from the task at hand.

• Rare Disease Reliance (House-MD Syndrome)

      >Over-analyzing or over-relying on rare diseases to explain a condition. This is the opposite of premature closure - this is where that phrase "when you hear hoofbeats, think horses, not zebras" comes from. This is easy to fall into when you're first learning about medical things - and is a common issue for med students. This will be explored further in 2.2 - Analysis vs Patterns, but for now, is important to note.

• Availability Heuristic
  

      >This is a common one in daily life as well - we use what we know or are most presently aware of as a shortcut. Think of COVID-19 - everyone with a cough or cold thought they had it during the pandemic, even if it was something unrelated. That's the availability heuristic - we go with what we know most well. Again, handy in normal life, but in a scientific context creates issues.

• Anchoring Bias

      >Sticking to the first diagnosis or idea that comes to mind. Again, happens all the time in daily life - we anchor ourselves to our first ideas for sake of simplicity. This becomes harmful when we refuse to acknowledge our first idea's faults, sticking with it to the end.

• Key Takeaway
  

      >Misdiagnoses aren't always errors in knowledge (although they certainly can be) - more often than not they are heuristics (mental shortcuts) taking place. Inherently, every human practice is tainted a little by heuristics, some more than others - and like in anything, education is the key. 

2.2: Diagnostic Process - Analysis vs Patterns

• Analysis
  >Analyzing a symptom or set of symptoms to figure out what it is. While this goes hand-in-hand with pattern recognition, over-analysis and overuse can create that House-MD syndrome. This is where pattern recognition comes to balance things out with analysis - much like signs and symptoms balanced one another earlier. Good example of this is analyzing where and when what pain is occurring in someone - and what could possibly cause that. While it's at the root - the more you stress possibilities, the more you can potentially confuse yourself.

• Pattern Recognition
  >Recognizing a set of symptoms more as a pattern of a specific disease, instead of analyzing what it could be. This goes hand-in-hand with analysis - as patterns are what make a diagnosis, but the specifics of those patterns must be analyzed for the correct diagnosis. For example: sure, nausea and vomiting can mean a stomach flu / bug, but by analyzing that diagnosis, referencing it with other factors (pregnancy, liver function, bulimia / anorexia symptoms) we can get closer to the truth. The best diagnosis, again, bridges the gap between analysis and patterns - blending both for a solid case towards a diagnosis.
  

2.3: Diagnostic Process - VINDICATE Acronym

V: Vascular. Blood & Heart
I: Infectious. Viral & Bacterial infection
N: Neoplastic. Meaning tumor / tumor growth - benign or malign cancer.
D: Degenerative. Alzheimers, Osteoarthritis, Parkinsons' etc. Get worse with age.
I: Idiopathic. Meaning 'disease of its own kind' - the mechanism is unknown.
C: Congenital. Meaning from birth - think birth defects, etc.
A: Autoimmune. When the body attacks itself (lupus, rheumatoid arthritis, etc.).
T: Trauma. As the name implies - think car crashes, bone breaks, etc.
E: Endocrine / Hormonal. Think diabetes, hypo/hyperthyroidism, gigantism, etc.

>This covers all types of diseases, allows simple recall and serves as a checklist. 

Part 3: To be continued...!