Here are some introductory resources from the Illness Scripts page of Exercises in Clinical Reasoning. I reviewed all the resources on the page which are linked to below:
Illness Scripts [Introduction]
An illness script is an organized mental summary of a provider’s knowledge of a disease (1-3). It represents a clinician’s knowledge about a particular disease, and may be as short as a 3×5 pocket card description for a rare disease, or as long as a book chapter for a commonly encountered illness. Classically, the components of a thorough illness script fall into three main categories: “the predisposing conditions, the pathophysiological insult, and the clinical consequences” (4). Within these categories, illness scripts often include a disease’s pathophysiology, epidemiology, time course, salient symptoms and signs, diagnostics, and treatment. For example, a provider’s illness script for community acquired pneumonia (CAP) may include:
Pathophysiology
- Infection of the lower respiratory tract
- Most commonly caused by Streptococcus pneumoniae
Epidemiology
Increased risk with:
- Age
- Post upper respiratory tract viral infection
- Structural lung disease
- Immunodeficiency
Time Course
- Acute (days)
- Progressively worsens if not treated
Salient Signs And Symptoms
- Fever
- Cough
- Shortness of breath
- Tachycardia
- Tachypnea
- Hypoxemia
Diagnostics
Labs and imaging:
- Leukocytosis
- Lobar infiltrate on chest x-ray
- Bacteria in sputum or blood cultures
Treatment
- Antibiotics typically lead to improvement over days
Building Illness Scripts
With experience, providers hone their illness scripts in three important ways (5).Encode Predictive Values
The absence of a fever does not exclude the diagnosis of CAP in an elderly patient.
Clinicians encode a predictive value for each feature of the disease, enabling them to estimate the likelihood of a diagnosis when that feature is present or absent.
Emphasize Distinguishing Features
A lobar infiltrate on chest x-ray without cardiomegaly or cephalization of vessels is highly suggestive of CAP and makes congestive heart failure less likely.
Clinicians emphasize distinguishing features whose presence or absence significantly alters the likelihood of the diagnosis, and helps differentiate it from another related diagnosis.
Consider Disease Mimics
Chronic obstructive pulmonary disease (COPD) exacerbation and congestive heart failure resemble CAP.
Clinicians develop a list of disease mimickers to consider when an illness script of a particular diagnosis is invoked.
Illness Script Explained [PDF]
- Case 1: 22W with abdominal pain
- Case
- Teaching Slides
- Instructor Guide
