Objective—To determine the efficacy and safety of
percutaneous ethanol injection (PEI) for the treatment
of hyperthyroidism caused by bilateral hyperplastic
thyroid nodules in cats.
Procedure—Hyperthyroidism was diagnosed on the
basis of clinical signs and increased serum total thyroxine
(TT4) concentrations. The presence of 2 cervical
thyroid nodules was confirmed by use of ultrasonography
and technetium Tc 99m albumin thyroid scans.
After the death of 1 cat that received PEI in both thyroid
nodules at the same time, the protocol was
changed to injecting ethanol into 1 nodule at a time,
with at least 1 month between injections. Clinical
signs, serum TT4 concentrations, serum ionized calcium
concentrations, laryngeal function, findings on
ultrasonographic examinations of the ventral cervical
region, and results of thyroid scans were monitored.
Results—Serum TT4 concentrations transiently
decreased in all 6 cats (into the reference range in 5 of
6 cats) within 4 days of the first staged ethanol injection.
Each subsequent injection resulted in a transient
decrease in serum TT4 concentration. The longest period
of euthyroidism was 27 weeks. Adverse effects
included Horner's syndrome, dysphonia, and laryngeal
paralysis. One cat died of unrelated causes. One cat
underwent bilateral thyroidectomy, 2 cats were treated
with methimazole, and 2 cats that had increased
serum TT4 concentrations were not treated further,
because they remained clinically normal.
Conclusions and Clinical Relevance—Percutaneous
ethanol ablation of bilateral thyroid nodules as a treatment
for cats with hyperthyroidism is not recommended.
This treatment is not as efficacious as the
medical and surgical treatments presently used.
(J Am Vet Med Assoc 2001;218:1293–1297)
Objective—To determine sensitivity and specificity of
radiography, ultrasonography, and antegrade pyelography
for detection of ureteral obstructions in cats.
Procedure—Medical records of cats that had radiography,
ultrasonography, and antegrade pyelography
performed for suspected ureteral obstructions were
examined. Ultrasound-guided pyelocentesis and fluoroscopic-
assisted antegrade pyelography were performed
on 18 kidneys in 11 cats. Obstructive ureteral
lesions were confirmed in all cats by surgical or
necropsy examination. Sensitivity and specificity of
survey radiography, ultrasonography, and antegrade
pyelography for identification of ureteral obstructions
were calculated. Surgical or necropsy findings were
used as the standard for comparison.
Results—All cats were azotemic. Mean ± SD serum
creatinine and BUN concentrations were 10.2 ± 6.1
and 149 ± 82 mg/dL, respectively. Fifteen of 18
ureters were found to be obstructed at surgery or
necropsy. Sensitivity and specificity were 60 and
100% for radiography and 100 and 33% for ultrasonography,
respectively, in identification of ureteral
obstructions. Leakage of contrast material developed
in 8 of 18 kidneys during antegrade pyelography and
prevented diagnostic interpretation in 5 of 18 studies.
For the 13 diagnostic studies, specificity and sensitivity
were 100% by use of the antegrade pyelography
technique. Correct identification of the anatomic location
of the ureteral obstruction was obtained in 100%
of diagnostic antegrade pyelography studies and in
60% of radiography or ultrasonography studies.
Conclusions and Clinical Relevance—Antegrade
pyelography can be a useful alternative in the diagnosis
and localization of ureteral obstructions in
azotemic cats, although leakage of contrast material
may prevent interpretation of the study. (J Am Vet
Med Assoc 2003;222:1576–1581)
Objective—To determine clinical, clinicopathologic,
radiographic, and ultrasonographic abnormalities in
cats with ureteral calculi.
Animals—163 client-owned cats.
Procedure—Medical records were reviewed, and
information on signalment, history, clinical signs, and
results of clinicopathologic testing and diagnostic
imaging was obtained.
Results—The number of cats in which ureterolithiasis
was diagnosed each year increased progressively during
the study period. Clinical signs tended to be nonspecific
and included inappetence, vomiting, lethargy,
and weight loss. A combination of survey radiography
and abdominal ultrasonography revealed ureteral calculi
in 66 of 73 (90%) cats in which the diagnosis was
confirmed at surgery or necropsy. Ultrasonography
revealed that ureteral calculi were causing ureteral
obstruction in 143 of 155 (92%) cats. One hundred
thirty-four of 162 (83%) cats had azotemia, 84 of 156
(54%) had hyperphosphatemia, and 22 of 152 (14%)
had hypercalcemia. Urinary tract infection was documented
in 10 of 119 (8%). Fifty-eight of 76 (76%) cats
with unilateral ureterolithiasis had azotemia and 33
(43%) had hyperphosphatemia, indicating impairment
of renal function in the contralateral kidney or prerenal
azotemia. Ultrasonographic imaging of the contralateral
kidney in cats with unilateral ureteral calculi suggested
that preexisting renal parenchymal disease
was common in cats with ureterolithiasis. Ninety-one
of 93 (98%) ureteral calculi contained calcium oxalate.
Conclusions and Clinical Relevance—Results suggest
that abdominal imaging should be performed in
all cats with chronic nonspecific signs or with acute
or chronic renal failure to rule out ureterolithiasis.
Preexisting renal disease may be common in cats
with ureteral calculi. (J Am Vet Med Assoc 2005;226:
Objective—To determine outcome of medical and
surgical treatment in cats with ureteral calculi.
Procedure—Medical records were reviewed.
Owners and referring veterinarians were contacted
for follow-up information.
Results—All cats were initially treated medically before
a decision was made to perform surgery. Medical treatment
included parenteral administration of fluids and
diuretics to promote urine production and passage of
the ureteral calculus and supportive treatment for renal
failure. Ureteral calculi in the proximal portion of the
ureter were typically removed by ureterotomy, whereas
ureteral calculi in the distal portion of the ureter were
more likely to be removed by partial ureterectomy and
ureteroneocystostomy. Ureterotomy could be performed
without placement of a nephrostomy tube for
postoperative urine diversion. Postoperative complication
rate and perioperative mortality rate were 31% and
18%, respectively. The most common postoperative
complications were urine leakage and persistent ureteral
obstruction after surgery. Chronic renal failure was
common at the time of diagnosis and continued after
treatment, with serum creatinine concentration remaining
greater than the upper reference limit in approximately
half the cats. Twelve-month survival rates after
medical and surgical treatment were 66% and 91%,
respectively, with a number of cats dying of causes
related to urinary tract disorders, including ureteral calculus
recurrence and worsening of chronic renal failure.
Conclusions and Clinical Relevance—Results suggest
that medical and surgical management of ureteral
calculi in cats are associated with high morbidity
and mortality rates. Treatment can stabilize renal function,
although many surviving cats will continue to
have impaired renal function. (J Am Vet Med Assoc