Constipation is the infrequent or
difficult passage of feces, often accompanied by the clinical sign of tenesmus,
or straining to defecate. However, when Eric sits in the litter box
and "strains" (according to the owner), the distinction must be made
as to whether Eric is straining to defecate or straining to urinate.
Dysuria is painful or difficult urination and may be seen as the result
of any disease of the lower urinary tract (bladder and urethra) or lower genital
tract (prostate and vagina) that results in mucosal irritation or
inflammation. One common cause of dysuria and lower urinary tract disease
in male cats is urethral obstruction. Any such blockages that persist for more than 24 hours
result in postrenal
azotemia; increased back-pressure impairs glomerular filtration, renal blood
flow, and, ultimately, tubular function. Thus, urethral obstruction
is a medical emergency and should be treated as such. Therefore,
it is extremely important that the distinction between the clinical signs of
tenesmus and dysuria be made immediately.