PUs:  yes, go to:
 
http://www.petcarevabeach.com/pen1.html
 
Hilbert got to avoid a PU.  He had plugging still after his bladder
diverticulum and sludge surgery and he wound up having cystos (Removal
of urine by needle.) which gave his urethra a chance to go down and
possibly dislodged a crystal or two in his urethra.
[Posted in FML issue 4674]