Echo what? echocardiogram? ECHO virus infection? echoencephalogram? Be certain of the meaning if you are going to expand the term. Otherwise, leave the prefix as dictated.
Epi
Epinephrine; spell it out
Epi sick
Pale, green, nauseous, chest-pounding, tachycardiac appearance of patient who has received aggressive subcutaneous epinephrine therapy in anaphylaxis or status asthmaticus