1. What are the three main steps of differential diagnosis? Explain each step briefly and

provide an example of how you would apply them in a clinical scenario.

Answer: The three main steps of differential diagnosis are:

- Identifying the chief complaint and the most likely diagnosis based on the history and

physical examination. For example, if a patient presents with chest pain, shortness of

breath, and diaphoresis, the most likely diagnosis is acute coronary syndrome (ACS).

- Generating a list of differential diagnoses that could explain the chief complaint and

the findings, and ranking them according to their probability and severity. For example,

besides ACS, other possible causes of chest pain include pulmonary embolism, aortic

dissection, pericarditis, pneumothorax, etc.

- Testing and refining the differential diagnoses by ordering appropriate investigations,

such as laboratory tests, imaging studies, electrocardiogram, etc., and interpreting the

results to confirm or rule out the diagnoses. For example, if the patient has elevated

cardiac enzymes and ST-segment elevation on ECG, the diagnosis of ACS is confirmed.

2. What are some common sources of diagnostic errors in acute care settings? How can

they be prevented or minimized?

Answer: Some common sources of diagnostic errors in acute care settings are:

- Cognitive biases, such as anchoring (focusing on the initial diagnosis and ignoring

contradictory evidence), confirmation bias (seeking evidence that supports the initial

diagnosis and ignoring evidence that refutes it), availability bias (relying on recent or

memorable cases), etc. These biases can be prevented or minimized by using structured

approaches to differential diagnosis, such as mnemonics, algorithms, checklists, etc.,

and by seeking feedback from peers or experts.

- Communication failures, such as inadequate handoffs, poor documentation, unclear

orders, etc. These failures can be prevented or minimized by using standardized tools

and protocols for communication, such as SBAR (situation-background-assessment-

recommendation), ISBAR (identify-situation-background-assessment-recommendation),

etc., and by verifying and clarifying information with other health care providers.

- System factors, such as time pressure, workload, fatigue, resource limitations, etc.

These factors can be prevented or minimized by prioritizing tasks according to urgency

and importance, delegating tasks when appropriate, taking breaks when needed, and

seeking help when necessary.