Illness script

The patient does not come to the doctor with a diagnosis but with complaints.
We have to compare these with our book knowledge and come up with a further diagnosis and treatment plan.
But this is where the ambush can lurk.
Medical textbooks are organized in such a way that each disease exists as an abstraction that lives its own ideal life.
Remember how disease information is usually presented there.

It is usually so-called horizontal reading.

Etiology → Epidemiology → Pathophysiology → Clinical Features → Diff ds → ect

books
This is a necessary but insufficient way to learn new material.

Over time, the amount of reading will increase tremendously, and human memory is unfortunately limited. Under stressful clinical conditions we will have to scramble to remember what a particular patients symptoms look like.

At some point, experts and cognitive psychologists began to study the problem of how a doctor in training could organize and arrange information so that the "right" section could be quickly found in memory when needed.

That's how the concepts of illness script and patient script have been created.

What is an illness script?
contrast-compaire

Illness script is the result of the processing of our book knowledge gained through horizontal reading.

As you gain clinical experience, new features and benefits will be added to the illness script.

But for now, we are at the very beginning of the journey. Let's try to filter the information so that we can extract only what is relevant to the four sections: Epidemiology, Time Course, Classic Clinical Features, Pathophysiology.

"Who commonly gets this disease"? It includes:
  • Age
  • Gender
  • Environmental factors
    • Living conditions
    • Travelling
    • Hobby

      How long has it been going on and what happens in between?
    • Hyperacute (hours)
    • Acute (days)
    • Subactute (weeks)
    • Chronic
      Patern of symptoms
    • Constant
    • Episodic

What are the classic signs or symptoms? What might you find on history and physical exam?

Important terms here are: Key and Differentiating features, Must Have features and Rejecting features.

What causes the disease?
Anatomy, physiology, immunological,biochemical pathways,genetics, ect
What are the known environmental contributors?
Microbiology,Toxins,Pharmacology

Now it's time to answer the following question:

Why do we need to store information in illness scripts ?
As mentioned above, a patient comes to the doctor with complaints that we often intuitively label with a collective term or leading syndrome. For example: complaints of headache, complaints of hemoptysis or chest pain.
Now that our knowledge is packaged in "illness scripts", we can go from horizontal reading to the vertical one using syndome driven clincal presentation diagnostic triads. It gets easier for us to connect them with logical links based on the patient's chief complaint.
These are no longer unconnected patterns but a network of patterns organized under the umbrella of the leading syndrome. This is how an experienced physician stores information in his memory.
What can help us to create logical connections inside the network ?
The following terms will help to answer this question:
  • Key or Differentiating features allow one to distinguish between diseases that may present with the same syndrome.

    Key feature of the diagnostic triad should be found only in one of the conditions and not in the other.

    Differentiating features are common to only two of the diagnosis
  • Must-have features Without it, the disease can't be diagnosed.
  • Rejecting Feature. If present, the diagnosis can't be made.

    For example, active reflexes are incompatible with a diagnosis of Guillian Barre Syndrome.

Let's look at the following diagram.

At the beginning of contrast learning let's start with three diseases with similar presentation. Two will be too little, more then three - too difficult. Expending the list begins to be hard to identify key features.

Organizing syndromes can be clinical or lab based.Just to remind you that we are talking about classic signs and symptoms.

    Patient with acute onset of headache

    List of our diff ds may consist of migraine, meningitis and intracranial bleeding. Let's try to compare theses diseases using terms above.

  • Vomiting signed as ⁕ is located at the center of the diagram. It's common in all three diseases. So it's not a differentiating feature.
  • Meningitis and intracerebral bleed may present with confusion and/or neck stiffness. This symptom is not present in migraine. This feature is common to only two of the diagnosis so we can called it differentiating.
  • Key feature of meningitis will be fever
  • Rejecting feature in meningitis will be normal spinal fluid (although there are some exceptions)
illness-scripts-diagram

The following example illustrates contrast approach as a table. Let's compare each set of elements of the illness-scripts which can help us to build a framework to store information for the future. Again we can use key features that should be a core element of these disease illness-scripts.

    Patient with hemoptysis

    Lets identify three diseases that might present with this syndrome. For example: Lung cancer, Goodpasture syndrome and Granulomatosis with polyangitis for the sake of illustration.

    Key features

  • Massive hemoptysis is common in Goodpasture's syndome but not for other diseases in the triad. Let's mark it as *** in the column Symptoms

  • Strong smoking history is a key feature of epidemology in many forms of Lung cancer but it's not a common feature of Goodpasture's syndrome or Granulomatosis with polyangitis So let's mark it as a Key feature in the table column Epidemiology.

    Differentiating feature in this triad is hematuria

  • Goodpasture's Sd and Granulomatosis with polyangitis present with glomerulonephritis but not Lung cancer. Let's put it as a differentiating feature in the column "Diff ds tests"

Disease Epidemiology Symptoms Diff dx tests
Lung cancer Smoking*** No hematuria
Goodpasture's syndrome Hemoptysis*** Hematuria +
Granulomatosis with polyangitis Hematuria +
Try to fill this table in. You shouldn't put too much information in one square unless it's either a key or a differentiating feature!
It's a quality of the facts to help you to distinguish between diseases with this given syndrome.
minus-sign What advantages does this approach have ?
Illness scripts help us to get rid of informational noise and facilitate the compare-and-contrast neural network connections. Storing information this way will allow us to recall it more efficiently in the clinical environment.
minus-sign What are the disadvantages of this approach ?
If patient presents with atypical symptoms we can miss the right diagnosis.
Now it's time to learn some methods to proccess history and results of physical exam.