Page 188 - Problem-Based Feline Medicine

180 PART 4 CAT WITH URINARY TRACT SIGNS

Abdominal palpation reveals a non-expressible, firm, – Widened QRS interval.
often painful, over-distended bladder. Cats obstructed – Spiked T wave.
for over 48 hours may show little or no signs of pain
Blood tests.
on abdominal palpation and in such cases, the bladder
● Changes in blood values (urea, creatinine, potas-
may rupture if handled other than with extreme care
sium, phosphorus, pH) depend on the severity of
and gentleness.
the renal failure.
Cats with partial obstruction may be able to maintain a ● Serum values are usually normal in cats with lower
small bladder size and not develop renal failure. Such urinary tract disease unless there is outflow obstruc-
cats show stranguria (painful urination with a narrower tion or rupture.
urine stream). – Post-renal azotemia (increased urea, creati-
nine), hyperphosphatemia, hyperkalemia
Signs of uremia indicate complete obstruction for at
become evident by 24 hours. Hypocalcemia is
least 48 hours.
variable. Mild hyperglycemia may be present.
● Depression, anorexia, vomiting, dehydration and
● The absence of clinical signs of hyperkalemia
hypothermia.
(bradycardia) does not eliminate the possibility of
● Hyperkalemia can cause bradycardia, ventricu-
severe hyperkalemia.
lar arrhythmia and general muscle weakness.
● Metabolic acidosis may exacerbate the effects of
hyperkalemia on the myocardium. Differential diagnosis
● Shock.
Urolithiasis occurs more often in middle-aged or older
Diagnosis cats.
History and physical examination. Functional urethral obstruction is often associated
● Acute onset of dysuria in a male cat. with other neurologic signs (see The incontinent cat).
● A distended, firm and often painful urinary blad- Urethral trauma usually has a history and hindquarter
der on abdominal palpation. lesions which are suggestive.
● Whitish, chalky material seen blocking the urethral
orifice or around the prepucal/perineal area. Stricture is usually preceded by a history of catheteri-
zation or trauma.
Urinalysis.
● Varying degrees of hematuria depending on the Neoplasia.
duration of the obstruction.
● Pyuria is variable.
TREATMENT
● Crystalluria is often seen and on many occasions
large crystals are found in the urine. The signifi- Depends on the severity of the clinical signs at presen-
cance of these large crystals is unclear. tation.
● Urinary pH and specific gravity values, at presenta-
If the cat is not showing clinical signs of renal failure or
tion, are variable, but pH is usually acidic and spe-
has not been obstructed for more than 24–36 hours,
cific gravity generally approaches 1.020 with
relieving the urethral obstruction and giving a bal-
prolonged obstruction.
anced electrolyte solution, subcutaneously or intra-
● Glucosuria is variable.
venously at 70 ml/kg is usually sufficient.
Radiography. Urethral plugs are often not visible on
If the cat is showing signs of renal failure, or has been
plain radiographs.
obstructed for more than 36–48 hours, correcting
Electrocardiography. the fluid and electrolyte imbalance takes priority
● Hyperkalemia (>6.0 mmol (mEq)/L). ECG changes over restoring urethral patency.
are often evident when K > 7 mmol(mEq)/L. ● Cats in post-renal renal failure must first be stabi-
– Bradycardia. lized before diagnostic tests, other than blood and
– Absence of a P wave. urine sampling, are undertaken.