Sam and Abby,
 
There are a couple of things that could cause these symptoms.  She could have
some type of congenital leg or spinal cord problem.  Some of these are very
treatable;  for example, patella luxation ( knee caps popping out of their
sockets).  Some of these problems require an orthopedic specialist to
diagnose.  Dark red stools could indicate a bacterial infection, parasites,
or stomach ulcers.  Abby is very young to have stomach ulcers.
 
A good physical exam and a fecal analysis would be a good place to start.
 
Good luck,
 
Dr. Weiss
(301) 299-4142
[Posted in FML issue 1287]