Hi Trex!
The difference between the two as you may know is that (a)
to cosider is active voice, whereas (b)
to be considered is passive.
passive must be used here because a question cannot "consider"=think. People can consider.
...... there's the question (of your health) to be considered
by us.
In other words,
we have to consider the question of your health.
or to be more accurate:
....there is the question of your health (that has) to be considered by us
I hope i've been of some help.If it isn't quite clear feel free to ask.