Yes as long as we can prove that the suffering is over and above what you would have experienced naturally because of the pre-existing condition.  If for example you were suffering from a spinal condition and an injury at work meant you lost your mobility a lot sooner than you would have otherwise had based on the progression of your condition we would be able to make a claim for you. On the other hand, if your pre-existing condition’s progression meant that you would have suffered the same level of injury regardless of the workplace accident’s impact on you things would be different.
As this is really complicated we can only answer this question fully on a case by case basis. Don’t allow the fact that you have a pre-existing condition to stop you from talking to an expert. You have nothing to lose and everything to gain.