Hi, newcomer and a big welcome. You are describing my earlier situation to a T. Something like 3/4 to 80% of people with MS will have urinary problems at some time.
You are having a common problem, called Urge Incontinence. This is a complex problem made up of a spazzy bladder in conjunction with a urethral sphincter that does always stay contracted at the right time. When the bladder contract, anytime the pressure in it is greater than the pressure of the purse string sphincter muscle in the outlet (urethra) urine will leak out.
In the early or mild times like you are having, about half of all people (men and women) with Urger Incontinence will benefit from exercises to strengthen the pelvic floor.
Last year when I was having your problem only with more severe leaking, I went through Incontinence Physical Therapy - ordered by my Uro-Gyencologist. It helped me IMMENSELY and kept me leak free for about six months. However, my incontinence got worse and now I am incontinent all the time. I am on 10mg of oxybutinin twice a day. But I still leak about a cup or so everytime and have to wear an incontinence pad 24/7.
I also urinate prophylactically everytime I am about to go somewhere for an extended period of time. Also I carry a bag with me at all times with multiple changes of underwear and clean pants (trousers for those in the UK, lol). Also adult wipes. Yes, it is a holy hassle.
Last year I wrote up a series of Health Pages detailing my experiences with all of this. You might find them interesting. They are a bit graphic, but they tell the truth.
The first is the explanation of how our bladders are supposed to work and some of the things that can go wrong.
http://www.medhelp.org/health_pages/Multiple-Sclerosis/The-Neurology-of-Bladder-Incontinence/show/758?cid=36
http://www.medhelp.org/health_pages/Multiple-Sclerosis/Urinary-Incontinence-Physical-Therapy---Part-I/show/759?cid=36
http://www.medhelp.org/health_pages/Multiple-Sclerosis/Urinary-Incontinence-PT---Part-Deux/show/760?cid=36
http://www.medhelp.org/health_pages/Multiple-Sclerosis/Urinary-Incontinence-PT--Part-Tres/show/761?cid=36
As soon as my leg is healed sufficiently I am going to finish the course of Badder PT with a trial of the electrical neurostimulation gadgets.
You have my entire sympathy. I know how horrible and motifying losing it in public is. Heck, I wasn't thrilled about losing it at home. It took a long time to get through the daily floods, mopping the floor and doing gads of extra laundry. I am still hoping to gain more control than the double dose oxybutinin gives me.
On the topic of meds. There are a wartload of meds out there for this problem. I had to work my way through several of them to find the one that worked the best for me. My Uro-Gyne says there is no way to predict which ones work the best. I started with Sanctura - no help at all. Then I tried Vesicare and it worked better, but my insurance wouldn't approve it until I had failed both Detrol LA and Oxybutinin ER. The Detrol made me sooooooooooooo sick, that at one point I thought I might be having a heart attack (and I am not that kind of worrier). However, the Oxybutinin worked as well as the Vesicare and I have stayed on it. It only has about a 10 hour action in me, even though it is supposed to be a 24hr med, so I take it every 12 hours. I only have mild side effects.
Why are some days worse than others and unpredictable? Good question and I have a couple possible answers.
The first is that the bladder can be surprisingly sensitive to certain foods. The most common of these are caffeine, coffee and tea - even decaffeinated, acidic foods like citrus or tomato products, chocolate, hot or strong spices, and dairy of any kind. When I first read that list I moaned because with the exception of caffeine, all of those form the b=very bsis of my ENTIRE DIET, thank you!
So, you might want to keep a food diary noting what food you have had in the prior 12 hours after your accidents or after you have had really strong or painful urgency.
The second thing that might be at work is some people, and I am one of them, hold extra fluid in my body after high-salt intake (my loves are Mexican, Italian and Chinese foods so salt is a major problem). Anyway, after one retains fluid, eventually the body lets go of it and you spend a day peeing like a race horse. Those days are more likely to be accident days for me.
Not everybody's incontinence gets worse and worse like mine did, so don't let that worry you. I would encourage you to read the health pages and to consider PT. Your accidents are mild and PT with strengthening the pelvic floor might just be enough to keep you safer.
Also, many of the incontinence supplies are more comfortable than you would expect. Since your leaks are small, the light-duty ones might keep you form those agonizing public problems.
I hope this helps.
Quix, MD