Q: 72 year old male, nursing home resident, admitted to ICU for Pneumonia and getting treated with Linezolid start having fever, agitation and myoclonus which is more pronounced in the lower limbs than in the upper limbs. What is your concern?

Answer: Serotonin Syndrome

One of the clinical diagnostic clue of Serotonin Syndrome is hyperreflexia and clonus more prononuced in the lower extremities than upper, at least in the moderate cases.

Reference:  Boyer, EW; Shannon, M (2005). "The serotonin syndrome". N Engl J Med 352 (11): 1112–20.