Toddler loss of bladder control

My sister is inquiring about my 4 year old niece.  For the past 2 weeks she has been weak and has had no appetite.  What is concerning is that she has been potty trained since the age of 2 and the last 4 days has urinated in her underwear which she says she didn't know she had to go.  Took her in for a urine cult which came back negative.  Any ideas of what could be causing this?

[Elicam]

Is she troubled about something? Maybe something happened at her nursery? Or could she have witnessed something disturbing?

When a toddler does these things, the first thing to rule out is some sort of mental trauma.

Good luck and hope she gets better soon.

[myproblem]

Any fever or other symptoms? Did the Dr. do anything else like a CBC? I remember when I was a little girl I didn't even really know I was sick, but I lost bladder control during a nap. It turned out I has pneumonia, but didn't have a cough from it. My friend's son also had pneumonia with no symptoms but fever, and not feeling right. A CBC would reveal if the body is fighting any type of infection. If this reveals nothing, then the Dr. should examine the possibility of a neurological cause for the loss of control.