After getting knocked out by Marquez, doctors had him checked for Parkinson's disease.
http://www.complex.com/sports/2013/01/doctors-concerned-manny-pacquiao-may-be-showing-early-signs-of-parkinsons-or-alzheimers
After the fight, Pacquiao took some extensive brain tests and based on those reports, Dr. Raquel Fortun, a forensics expert from the Philippines, believes that something is not right as well.
"When the brain gets shook like that, it's very dangerous. Since it's not truly fixed to you skull, when your brain gets shaken, there are connections that get cut off, and you get small hemorrhages."
Leg cramps is a symptom of Parkinson. Manny has been developing leg cramps which he uses $2,000 creams to alleviate.
Leg Cramps and Restless Leg Syndrome
Having Parkinson's disease can also lead to leg pain or cramps that can be especially worse at night. They may come on suddenly and be quite severe. Leg cramps may subside as you put pressure on the affected leg and move around. You may also develop restless leg syndrome which is an urgent need to move your legs when you are trying to rest.
http://www.livestrong.com/article/68136-parkinsons-disease-leg-symptoms/
Ali was in denial of his Parkinson's disease during the end of his boxing career. Many fans believe Ali should have retired before his last few fights and should have never fought Larry Holmes.
Pacquiao fighting Mayweather may end up like the Ali-Holmes fight. Mayweather fights a lot like Holmes and after Mayweather beats Pacquiao, I would hope he considers retiring before his early signs of Parkinson's disease gets worse.