How you can rewrite pathways like:

/xyz/ijk?a=b&c=d

to index.php:

/index.php/xyz/ijk?a=b&c=d

However with variable PATH_INFO = /abc/ijk as it is after i avoid using rewrite (/index.php/abc/ijk?a=b&c=d)

Try something similar to this:

RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ index.php/$1 [QSA ]