These are foundational questions about clinical issues best answered using a textbook or other reference source.
Ex. What is cancer cachexia and what is its pathophysiology?
These are questions that can be answered using the best current research.
Ex. Is a fish oil enhanced nutritional supplement effective in stablizing weight in patients with advanced cancer?
A well-built clinical question is directly relevant to patient care and helps guide searching for evidence-based answers. There are generally four components of a good clinical question and they are represented by the acronym PICO.
P - Patient, population or problem of interest
I - Intervention - therapy, diagnostic test, exposure, etc.
C - Comparison intervention or comparison of interest
O - Outcome(s) of interest
For example, you might start by wondering, Is Vitamin C more effective than echinacea in preventing the common cold? - you'll need to restate your question in the PICO format to get a clincal answer.
The PICO format will
help you translate your question from an initial broad topic or
specific, individual patient's experience, to a concrete, objective
question that you can find clinical evidence to answer.
The Evidence-Based Practice Tutorial for Nurses from Penn State University gives details and examples about each of these aspects of your question.
The Centre for Evidence Based Medicine has tips and practice examples for formulating research quesitons.