I don't know about a time frame, but once a cat has blocked, the probability
increases that he may block again. Provide plenty of water dishes and keep
track of his urinating.
Gail

It is especially crucial to realize that the cat is at risk for
re-blocking for a good week or two from the time of discharge. This is
because the irritation syndrome that led to blocking in the first place is
still continuing and as long as the episode continues, blocking is a
possibility.

     At home, the same straining and bloody urine will still be produced.
It is important for the owner to be aware of urine volume being produced and
of bladder size, if possible. Any loss of appetite or vomiting should be
reported to the veterinarian at once. If there is any concern about
reblocking, the veterinarian can determine fairly easily if the cat has
re-blocked.

     Most cats recovery uneventfully and most do not need continuing
medication after they have recovered. Some cats, especially if they have
blocked before, will require on-going treatment.

     Occasionally the bladder over-stretches while it is blocked and is
permanently damaged. Such cats require special medication to help them
contract and empty their bladders normally. This is unusual but one should
be aware of the possibility.

     FUTURE MANAGEMENT

     Once the cat is no longer obstructed, management is the same as for
any other cat with feline lower urinary tract that is not obstructed. For
more details, click here.

     THE PERINEAL URETHROSTOMY

     Urinary blockage is almost exclusively a problem reserved for males.
This is because the female urethra is shorter and broader, in short, far
more difficult to obstruct. When urinary blockage becomes recurrent in a
male cat, it becomes time to consider surgical reconstruction of the
genitalia to create a more female-like opening. This surgery is called the
Perineal Urethrostomy or "PU" for short. Basically, the penis is removed and
a new urinary opening is made.

     Before considering this surgery, here are some considerations:

       a.. This surgery is done to prevent obstruction of the urinary
tract. It does not prevent Feline Lower Urinary Tract Disease. This means
the cat is likely to continue to experience recurring bloody urine,
straining etc. He just will not be able to block and complicate the
situation.

       b.. Cats with perineal urethrostomies are predisposed to bladder
infections and infection related bladder stones.  The University of
Minnesota currently recommends that male cats with perineal urethrostomies
have regular periodic urine cultures even if they are asymptomatic. This
basically means that your cat should have a vet visit and testing 3 or 4
times a year for urine cultures.
     WHAT YOU NEED TO KNOW IF YOU ARE
     CONSIDERING THIS PROCEDURE FOR YOUR CAT:

       a.. The metabolic complications from the urinary blockage should be
resolved before the surgery is performed. In some emergency situations this
is not possible (the male cat cannot always be unblocked with a urinary
catheter and a new urinary opening may have to be constructed on an
emergency basis.) Residual urinary toxin build up is an important risk
factor that should be eliminated or minimized if possible.

       b.. Shredded paper or pelleted newspaper litter should be used
during the 10 days following surgery. Clay and sand litter may stick to the
incision and disrupt healing.

       c.. The most serious complication that can occur post-operatively is
scar ("stricture") formation. This causes a narrowing of the urinary opening
and the surgery may have to be revised.

       d.. In theory, local nerve damage can occur during the surgery
leading to urinary and/or fecal incontinence. Obviously these are disasters
for a household pet but fortunately this is a very rare complication.

       e.. As mentioned, regular urine cultures are recommended for cats
with perineal urethrostomies.