Your literature search will be more successful if you first spend some time developing a research question, and if you revisit and revise that question as you find out new information. Terms in your question will guide your database searching.
Your question should be:
PICO: Use the acronym PICO to help consider variables that you want to include in your question.
P - problem, population, patient (some specific population or patient variables are age or life stage, gender, race, income, education, geographic location, etc. AND in the case of non-humans, consider species and breed)
I - Intervention
C - Comparison, Correlation
O - Outcome
Type of Question: In a clinical setting, questions relate to treatment, diagnosis, etiology (cause), prognosis, and quality of life. You will not address all of these in a single question.
Synonyms: Spend some time brainstorming about other terms used for the same concept, either in a modern setting or historically. Most likely you will discover more of these as you start searching
Refine your question based on your preliminary literature review. By stating your problem as a question, rather than a list of terms, you will be more likely to assure that it is answerable.