If it's osteoarthritis, it may get worse with use. It would be wise to check out larger grips, and anything else that would widen the grip on the brake handles and bars.
Sometimes a preventive dose of ibuprofen before such use can make a big difference.
San Francisco Area
ESR'd March 2010. FIRE'd January 2011.
As if you didn't know..If the above message contains medical content, it's NOT intended as advice, and may not be accurate, applicable or sufficient. Don't rely on it for any purpose. Consult your own doctor for all medical advice.