I have got a 6yr old staffie, The last 3 months we have found the following:
1)  Blood spots on his bed - we put this down to a infection he has on this paw as that bleeds
2) drinking more - we changed his food from canned to dried and was told that he would drink more
3) Sleeping more and having problems getting up the steps in the garden - we thought this was a aged related thing.
He also has a slight heart murmur.

We have regulary checked him over but could not find any blood in the paws, ears, mouth ect this morning 22-06-08 we found blood on his penis, we immediatley rang the emergency vets, we took him there and being a male had to have a wee before going in, this was just blood no urine what ever.  The vet examined him and came up with 3 possabilitys;
1) unrine infection
2) stones in the bladder
3) prostate problem ( the vet thinks this is the most likely as they are concurrent with drinking more, sleeping and mobility)
I have had to leave him there for scans and x-rays but what could the worst be, is it life threatening and could someone give me more information on what a prostate problem is?

Is your dog castrated?

No not yet anyway.  He has been at the vets for 4hrs now and no phone call this is killing me.

My old mutt (14yrs) had all the symptoms of an enlarged prostate/bladder stones but as the vet felt the prostate to be not enlarge he treated for cystitis, with a view to scan/xray dog after 24 hrs if no improvement. The anti-biotics had a major effect in the first 24 hours, so he continued the course and was right as rain :)
It was a very scarey time, I really though he was going to die, puddles of what looked like pure blood were just running from him :(

I think (but am not sure) that several things can cause an enlarged prostate, including hormones (then a castration would be needed), infection, tumors, cyst etc.. So it really depends on what the problem is with the prostate as to how it will be treated/prognosis.

I hope you get some news soon, the waiting must be torture and I hope it is something easily treatable.

Only asked about that as there is a prostate problem that can be sorted by castration, but think that is only if the problem is caused by androgen (male hormone). This type is common in dogs over 5 years and can be treated with female hormone or castration. Believe this does exhibit the symptoms you have discribed but so can infection so you will have to wait on the vets tests. Sometimes this condition is accompanyed by a cyst developing.

Prostatic tumours are uncommon in dogs and even more uncommon in intact dogs so I think for the time being I would not even consider that.

Well 7 hours later I got my baby back from the vets.  He has got a prostate problem, the prostate is 3 to 4 times bigger then it should be, infact when they did the x-rays the vet said they thought it was his bladder. He has been put on antibiotics until Thursday when he has to go back to our own vets and more scans will be done but they did say he may now need to be castrated as the problem will keep coming back and also there is the risk of cyst.

Thank to all that replied the last 7 hours have been hell and it lovely to have my baby back again.

Glad you have him back and although it is a shock the castration will cure the problem, it seems as if it is straight forward and he has not as yet developed a cyst so I am sure given a few week he will be back to normal health.

Well today I have had to take him back as he is constantly crying in pain, they have given him a pain killing injection of a kind of morphine, he is booked in tomorrow to be castrated, they said they need to do this as quick as possible as it can speed up the shrinking of the prostate, they then want to xray him again in a week as the emergency vet thinks a cyst may be present. Just feel so sorry for him at the moment as he carnt get comfortable and is crying out in pain and has not eaten since saturday night.

Poor thing :(
Good luck for his op tommorrow. I hope he's feeling better soon.