Objective—To determine the prevalence and clinical features of cryptogenic epilepsy among dogs.
Design—Retrospective case series.
Animals—214 client-owned dogs with onset of epileptic seizures at ≥ 7 years of age.
Procedures—A diagnostic imaging database was searched for dogs with symptomatic or cryptogenic epilepsy. Signalment, seizure history, and diagnostic information were recorded. Information regarding seizure frequency, administration of antiepileptic drugs (AEDs), owners' perceptions regarding quality of life, survival times, and causes of death for dogs with cryptogenic epilepsy was obtained via questionnaire. Variables were compared among dogs grouped according to diagnosis and age.
Results—45 (21%) dogs had a diagnosis of cryptogenic epilepsy, and 169 (79%) had symptomatic epilepsy. In dogs 7 to 9 years and ≥ 10 years of age at the time of seizure onset, 31 of 106 (29%) and 14 of 108 (13%), respectively, had a diagnosis of cryptogenic epilepsy. At last follow-up, most (40 [89%]) dogs with cryptogenic epilepsy were receiving ≥ 1 AED. Thirty-one of 37 (84%) dogs typically had ≤ 1 seizure/mo following hospital discharge. Death was confirmed in 20 (44%) dogs with cryptogenic epilepsy and was related to seizures or AEDs in 7 Median survival time from onset of seizures was 52 months for all dogs with cryptogenic epilepsy. Median quality-of-life score (scale, 1 [poor] to 10 [excellent]) indicated by 34 owners of dogs with cryptogenic epilepsy was 10 before diagnosis and initiation of AED treatment and 8 afterward.
Conclusions and Clinical Relevance—Cryptogenic epilepsy was diagnosed in a substantial proportion of dogs with an onset of epileptic seizures at ≥ 7 years of age. Seizure control was considered acceptable in most dogs.
Objective—To measure pharmacokinetics of levetiracetam (LEV) after single-dose oral administration in healthy dogs and determine whether pharmacokinetics changed after repeated oral dosing.
Animals—6 healthy adult dogs.
Procedures—Pharmacokinetics were calculated following administration of a single dose (mean, 21.7 mg/kg, PO; day 1) and after administration of the last dose following administration for 6 days (20.8 to 22.7 mg/kg, PO, q 8 h; days 2 to 7). Plasma LEV concentrations were determined by use of high-pressure liquid chromatography. Pharmacokinetic data were analyzed by use of a 1-compartment model with first-order absorption.
Results—Peak concentration occurred 0.6 hours after administration of the first dose, with an absorption half-life of 0.06 hours. Minimal accumulation occurred over the 7 days, with only a slight increase in total area under the concentration-versus-time curve from 268.52 ± 56.33 h·μg/mL (mean ± SD) to 289.31 ± 51.68 h·μg/mL after 7 days. Terminal half-life was 2.87 ± 0.21 hours after the first dose and 3.59 ± 0.82 hours after the last dose on day 7. Trough plasma concentrations were variable, depending on the time of day they were measured (morning trough concentration, 18.42 ± 5.16 μg/mL; midday trough concentration, 12.57 ± 4.34 μg/mL), suggesting a diurnal variation in drug excretion.
Conclusions and Clinical Relevance—Results indicated that the pharmacokinetics of LEV did not change appreciably after administration of multiple doses over 7 days. Administration of LEV at a dosage of 20 mg/kg, PO, every 8 hours to healthy dogs yielded plasma drug concentrations consistently within the therapeutic range established for LEV in humans.
Objective—To develop a multiplex polymerase chain
reaction (PCR) assay for the detection of Toxoplasma
gondii and Neospora caninum DNA in canine and
feline biological samples.
Sample Population—Biological samples from 7 cats
with systemic (n = 4) or CNS (3) toxoplasmosis, 6 dogs
with neospora- or toxoplasma-associated encephalitis,
and 11 animals with nonprotozoal disease.
Procedure—Primers for T gondii, N caninum, and the
canine ferritin gene (dogs) or feline histone 3.3 gene
(cats) were combined in a single PCR assay. The DNA
was extracted from paraffin-embedded brain tissue,
CSF, or skeletal muscle. The PCR products with positive
results were cloned, and sequence identity was
Results—Of 7 cats and 4 dogs with immunohistochemical
or serologic evidence of toxoplasmosis, PCR
results were positive for all cats and 3 dogs for T gondii,
and positive for T gondii and N caninum for 1 dog.
Another dog had negative PCR results for both parasites.
Of 2 dogs with immunohistochemical or serologic
evidence of neosporosis, PCR results were positive
for 1 for N caninum and positive for the other for
T gondii. All negative-control samples yielded negative
results for T gondii and N caninum on the PCR assay.
Conclusions and Clinical Relevance—Standard tests
for toxoplasmosis or neosporosis associated with the
CNS rely on serologic, histologic, or immunohistochemical
analysis and can be difficult to interpret. The
multiplex PCR assay with built-in control reactions
could be a complementary clinical tool for the antemortem
diagnosis of toxoplasmosis or neosporosis
associated with the CNS. (Am J Vet Res 2003;64:1507–1513)
To investigate caregivers’ assessments of outcome in dogs with idiopathic epilepsy (IE) administered levetiracetam (LEV), zonisamide (ZNS), or phenobarbital (PB) monotherapy.
100 dogs with IE administered LEV (n = 34), ZNS (31), or PB (35) monotherapy between January 1, 2003, and February 6, 2019, and survey responses from their caregivers.
Information on duration of therapy, adverse effects (AEs), and outcome was obtained from medical record review and caregiver questionnaire.
A significant improvement in mean quality of life score was reported during monotherapy (7.7; SD, 2.14) compared to before treatment (6.25; SD, 2.63; P < .0001), with no difference identified between monotherapy groups. Compared to ZNS monotherapy, dogs prescribed PB monotherapy had a significantly younger median age at seizure onset (2.6 vs 4.3 years; P = .024). A significant relationship was identified between the occurrence of reported AEs and monotherapy group, with a higher prevalence in the PB group (77% [27/35]) and a lower prevalence in the ZNS group (39% [12/31]; P = .0066). Treatment failure rates for PB, LEV, and ZNS monotherapy were 51%, 35%, and 45%, respectively, with failure attributed most commonly to inadequate seizure control. No significant difference was identified between groups with respect to rate of or time to failure.
Most caregivers reported a favorable outcome with administration of LEV, ZNS, or PB monotherapy to dogs with IE. Phenobarbital is associated with the highest prevalence of AEs but no difference in quality of life score. Prospective controlled studies are needed to further compare the efficacy and safety of these monotherapies in dogs with IE.
Objective—To determine long-term (> 6 months) outcome
of dogs with paraplegia and loss of hind limb
deep pain perception (DPP) resulting from intervertebral
disk herniation or trauma.
Procedure—Outcome was determined as successful
or unsuccessful. The association of neuroanatomic
localization, breed, age, weight, sex, and (for dogs
with intervertebral disk herniation) speed of onset of
signs and duration of paraplegia prior to surgery with
outcome was evaluated. Owners were contacted by
telephone to identify long-term health problems.
Results—Nine of 17 dogs with traumatic injuries
were treated, and 2 regained the ability to walk;
none of the 17 dogs regained DPP. Sixty-four of 70
dogs with intervertebral disk herniation underwent
surgery; 9 (14%) were euthanatized within 3 weeks
after surgery (7 because of ascending myelomalacia),
37 (58%) regained DPP and the ability to walk,
7 (11%) regained the ability to walk without regaining
DPP, and 11 (17%) remained paraplegic without
DPP. Outcome was not associated with any of the
factors evaluated, but speed of recovery of ambulation
was significantly associated with body weight
and age. Fifteen (41%) and 12 (32%) dogs that
regained DPP had intermittent fecal and urinary
Conclusions and Clinical Relevance—Results suggested
that the prognosis for paraplegic dogs without
DPP because of trauma was guarded, while dogs
with disk herniation had a better chance of recovering
motor function. A third of the dogs that recovered
motor function had intermittent incontinence.
Persistent loss of DPP did not preclude recovery of
motor function, but such dogs remained incontinent.
(J Am Vet Med Assoc 2003;222:762–769)
Objective—To identify risk factors for episodes of
status epilepticus (SE) in dogs with idiopathic epilepsy
and determine how SE affects long-term outcome
and survival time.
Animals—32 dogs with idiopathic epilepsy.
Procedure—Information on signalment, seizure
onset, initiation of treatment, anticonvulsants administered,
number of episodes of SE, overall seizure
control, and long-term outcome was obtained from
medical records and through telephone interviews.
Differences between dogs that did and did not have
episodes of SE were evaluated statistically.
Results—19 (59%) dogs had 1 or more episodes of
SE. Body weight was the only variable significantly
different between dogs that did and did not have
episodes of SE. Thirteen dogs (9 that did not have
episodes of SE and 4 that did) were still alive at the
time of the study and were ≥ 10 years old. Six of the
19 (32%) dogs that had episodes of SE died of causes
directly attributed to the seizure disorder. Mean life
spans of dogs that did and did not have episodes of
SE were 8.3 and 11.3 years, respectively. Survival
time was significantly different between groups.
Conclusions and Clinical Relevance—Results suggest
that a substantial percentage of dogs with idiopathic
epilepsy will have episodes of SE. Dogs with
greater body weights were more likely to have
episodes of SE, and early appropriate seizure treatment
did not appear to decrease the risk that dogs
would have episodes. Most dogs with idiopathic
epilepsy had an expected life span, but survival time
was shorter for dogs that had episodes of SE. (J Am
Vet Med Assoc 2001;219:618–623)
Objective—To identify predictive factors of long-term
outcome after dorsal decompressive laminectomy for
the treatment of degenerative lumbosacral stenosis
(DLSS) in dogs.
Sample Population—69 client-owned dogs.
Procedure—Medical records of dogs that had undergone
dorsal laminectomy at North Carolina State
University and the University of Tennessee between
1987 and 1997 were reviewed. Dogs with
diskospondylitis, traumatic lesions, or neoplasia of
the lumbosacral region were excluded. All dogs had
evidence of cauda equina compression on myelography,
epidurography, computed tomography, or magnetic
resonance imaging, along with subsequent confirmation
of the lesion at surgery. Follow-up was performed
by telephone inquiries to the referring veterinarian,
the owner, or both, using a detailed questionnaire.
Results—The outcome was excellent or good in 54 of
69 (78%) dogs over a mean follow-up period of 38 ±
22 months. Five of these 54 dogs had been incontinent
for a median of 2 weeks prior to surgery. Six of
the 15 dogs with a poor outcome had been incontinent
for a median of 8 weeks before surgery. A significant
correlation was detected between the presence
of urinary and fecal incontinence prior to surgery
and outcome. When duration of signs was considered,
urinary incontinence was the only variable that
significantly affected outcome.
Conclusions and Clinical Relevance—Decompressive
laminectomy is an effective treatment for
DLSS, although dogs with urinary or fecal incontinence
have a worse prognosis than dogs that are continent
before surgery. Chronic urinary incontinence is
a predictor of poor outcome for dogs with DLSS. (J
Am Vet Med Assoc 2001;219:624–628)
Objective—To develop and compare the reliability of
2 methods of scoring pelvic limb gait in dogs recovering
from thoracolumbar spinal cord injuries and to use
this scoring system to determine the rate and level of
functional recovery of dogs with acute thoracolumbar
intervertebral disk herniations.
Animals—46 dogs with spinal cord injuries resulting
from intervertebral disk herniations.
Procedure—Dogs' gaits were videotaped at different
time intervals after injury. In phase 1 of the study, the
stages of recovery of pelvic limb function were identified,
and a numeric scoring system was devised to
reflect that recovery. In phase 2, pelvic limb gait was
scored by different observers, using a numeric and a
visual analog scale. Intra- and interobserver coefficients
of variability of both methods were compared.
In phase 3, pelvic limb function was scored, using the
numeric scale at various intervals after acute thoracolumbar
Results—The numeric scale was significantly more
reliable than the visual analog scale when both intraand
interobserver coefficients of variability were evaluated.
Dogs that were paraplegic with no deep pain
sensation recovered at different rates during the first
3 months, whereas dogs that were paraplegic with
deep pain sensation typically recovered within 1
month of injury.
Conclusion and Clinical Relevance—Pelvic limb gait of dogs recovering
from thoracolumbar spinal cord injuries can be reliably
quantified, using a numeric scale. This scale will facilitate
the performance of clinical trials aimed at
improving the outcome of acute spinal cord injuries.
(Am J Vet Res 2001;62:1624–1628)
Procedure—A programmable pacemaker-like device
designed to deliver intermittent stimulation to the left
cervical trunk of the vagus was surgically implanted in
each dog. Dogs were assigned randomly to two 13-
week test periods, 1 with nerve stimulation and 1
without nerve stimulation. Owners recorded data on
seizure frequency, duration, and intensity, as well as
Results—No significant difference in seizure frequency,
duration, or severity was detected between
overall 13-week treatment and control periods.
During the final 4 weeks of the treatment period, a
significant decrease in mean seizure frequency
(34.4%) was detected, compared with the control
period. Complications included transient bradycardia,
asystole, and apnea during intraoperative device testing,
and seroma formation, subcutaneous migration
of the generator, and transient Horner's syndrome
during the 14-day period between surgery and suture
removal. No adverse effects of stimulation were
detected, and most owners were satisfied with the
Conclusions and Clinical Relevance—Vagal nerve
stimulation is a potentially safe approach to seizure
control that appears to be efficacious in certain dogs
and should be considered a possible treatment option
when antiepileptic medications are ineffective. (J Am
Vet Med Assoc 2002;221:977–983)
To investigate the feasibility and pharmacokinetics of cytarabine delivery as a subcutaneous continuous-rate infusion with the Omnipod system.
6 client-owned dogs diagnosed with meningoencephalomyelitis of unknown etiology were enrolled through the North Carolina State University Veterinary Hospital.
Cytarabine was delivered at a rate of 50 mg/m2/hour as an SC continuous-rate infusion over 8 hours using the Omnipod system. Plasma samples were collected at 0, 4, 6, 8, 10, 12, and 14 hours after initiation of the infusion. Plasma cytarabine concentrations were measured by high-pressure liquid chromatography. A nonlinear mixed-effects approach generated population pharmacokinetic parameter estimates.
The mean peak plasma concentration (Cmax) was 7,510 ng/mL (range, 5,040 to 9,690 ng/mL; SD, 1,912.41 ng/mL), average time to Cmax was 7 hours (range, 4 to 8 hours; SD, 1.67 hours), terminal half-life was 1.13 hours (SD, 0.29 hour), and the mean area under the curve was 52,996.82 hours X μg/mL (range, 35,963.67 to 71,848.37 hours X μg/mL; SD, 12,960.90 hours X μg/mL). Cmax concentrations for all dogs were more than 1,000 ng/mL (1.0 μg/mL) at the 4-, 6-, 8-, and 10-hour time points.
An SC continuous-rate infusion of cytarabine via the Omnipod system is feasible in dogs and was able to achieve a steady-state concentration of more than 1 μg/mL 4 to 10 hours postinitiation of cytarabine and a Cmax of 7,510 ng/mL (range, 5,040 to 9,690 ng/mL; SD, 1,912.41 ng/mL). These are comparable to values reported previously with IV continuous-rate infusion administration in healthy research Beagles and dogs with meningoencephalomyelitis of unknown etiology.