Page 190 - Problem-Based Feline Medicine

182 PART 4 CAT WITH URINARY TRACT SIGNS

(Wallpoles buffer solution) into the bladder to – A closed urine drainage system is often imprac-
dissolve any struvite crystals. If the catheteri- tical in the cat. However, it should be used if
zation was achieved with minimal trauma, an indwelling catheters are to be left in for more
indwelling catheter is not required. than 3–4 days. A closed drainage system
– If hematuria is present: Wallpoles buffer involves connecting the urinary catheter, via
solution should not be used. extension tubing, to a sterile, empty fluid bag
– Instill 100 mg of ampicillin in 20 ml of normal below the cat.
saline into the bladder. Give parenteral antimi- – Indwelling catheters should be used for as short
crobials that are not nephrotoxic, such as amox- a time as possible to minimize catheter-induced
icillin/clavulanate, enrofloxacin. Leave the iatrogenic disease.
urinary catheter in situ for as shorter a time as – Beginning the cat on phenoxybenzamine
possible. Indwelling catheters can induce further (2.5–10 mg PO q 8–2 h) may help to reduce re-
damage to the urothelium by disrupting its gly- obstruction or dysinergia once the catheter is
cosaminoglycan coating and thus promote removed.
microbial adherence and urinary tract infection. – An Elizabethan collar and/or hobbles on the hind
Remove the indwelling catheter once hema- legs using self adhesive tape or elastoplast may
turia is no longer visible. be necessary to prevent the cat interfering with
● An indwelling catheter is required if: the urinary catheter.
– Obstructing material was expelled into the uri- – Most cats will not interfere with a properly
nary bladder. placed or correctly selected indwelling urinary
– Severe urethral trauma occurred associated with catheter. Interference usually indicates poor
removal of the plug. Significant trauma occurs if catheter placement or catheter-induced irritation.
excessive force or repeated catheterization – The use of antimicrobial therapy to prevent sec-
attempts are necessary to unblock the urethra. ondary urinary tract infection is controversial.
– A large amount of potentially obstructing debris – To avoid developing resistant organisms, it is
is present in the bladder, which may be deter- recommended that a broad-spectrum antimicro-
mined during bladder empting, by palpation of bial, such as amoxicillin be used only once
the empty bladder, or by radiography/ultra- infection occurs.
sonography. – Evidence that an infection is occurring includes
– Urine stream after relief of the obstruction is the appearance of hematuria or increasing hema-
narrower than normal. turia, bacturiuria and pyuria.
– The urinary bladder does not contract normally – Removal of the catheter at the first signs of uri-
after emptying, indicating atony. nary infection may obviate the need for antimi-
– Re-obstruction occurs, especially within 24 crobial therapy.
hours. – Follow-up urine culture and susceptibility tests
– Measurement of urine flow rate is required dur- are essential to determine treatment success.
ing intensive care of critically ill cats. – Once the catheter is removed, the cat should be
– In these situations, the advantages of maintain- keep in hospital for a further 24 hours to ensure
ing urethral patency and decompression of a that it can urinate freely.
chronically distended, devitalized bladder out- ● If the obstruction cannot be relieved:
weighs the disadvantages of ascending bacterial – General anesthesia in an unanesthetized patient
infection and ongoing damage to the urethral may help to relieve urethral spasm, and the
mucosa. intraluminal pressure present in the urinary blad-
– Silicone elastomer catheters (Wysong urethral der and urethra may facilitate the removal of the
catheter) are preferred as they are soft, pliable, obstructing material.
less irritant to the urethral mucosa and curl – The use of acid buffer solutions to dissolve the
up inside the bladder without kinking as the obstructing material is ineffective and time
bladder empties, thus avoiding bladder wall wasting, especially if the cat is in post-renal
irritation. renal failure.