What kind of stress was affecting Scott Fischer during the summit attempt?

Fischer’s energetic demeanor over the past few weeks belied his mental and physical exhaustion from leading the Mountain Madness expedition. Unbeknownst to most of the climbers, he suffered from a chronic liver condition that caused short but debilitating spells of fever when his body was under increased stress. Krakauer speculates that this may have contributed to Fischer’s lagging pace on summit day. Just past 3:00pm, Beidelman decides that he can’t wait for Fischer any longer and begins descending with five clients.