Objective—To evaluate the clinical features and heritability of naturally occurring hypoadrenocorticism in Nova Scotia Duck Tolling Retrievers (NSDTRs).
Design—Retrospective case series.
Animals—25 NSDTRs with hypoadrenocorticism.
Procedures—Questionnaires completed by owners of NSDTRs with hypoadrenocorticism and medical records from veterinarians were reviewed for information regarding diagnosis, age at diagnosis, concurrent diseases, age at death, and cause of death. Pedigrees were analyzed for heritability and mode of inheritance of hypoadrenocorticism (including complex segregation analysis of pedigrees of 1,515 dogs).
Results—On the basis of results of ACTH stimulation testing, hypoadrenocorticism was diagnosed in 16 female and 9 male NSDTRs (including 6 full siblings). Median age at diagnosis was 2.6 years; the diagnosis was made prior to 2 years of age in 11 dogs. Seventeen dogs had hyponatremia, hyperkalemia, or both, and serum electrolyte concentrations were within reference ranges for 8 dogs at the time of diagnosis. Median survival time after diagnosis for 4 dogs that died or were euthanized as a result of medical causes was 1.6 years. Heritability was calculated at 0.98 with no sex effect, and complex segregation analysis fit a major gene model with an autosomal recessive mode of inheritance.
Conclusions and Clinical Relevance—In NSDTRs, hypoadrenocorticism was diagnosed at an earlier age, compared with published reports of age at diagnosis among the general dog population. Among the study dogs, 32% had no serum electrolyte abnormalities at the time of diagnosis, and the disease appeared to have an autosomal recessive mode of inheritance in the breed.
Objective—To evaluate serum 17-hydroxyprogesterone
(17-OHP) concentration measurement after
administration of ACTH for use in the diagnosis of
hyperadrenocorticism in dogs.
Procedure—Serum 17-OHP concentrations were
measured before and after ACTH stimulation in 53
healthy dogs to establish reference values for this
study. Affected dogs had pituitary-dependent (n = 40)
or adrenal tumor–associated (12) hyperadrenocorticism
or potentially had atypical hyperadrenocorticism
(5; diagnosis confirmed in 1 dog). In affected dogs,
frequency interval and borderline and abnormal
serum 17-OHP concentrations after ACTH stimulation
were determined. Serum cortisol concentrations
were assessed via low-dose dexamethasone suppression
and ACTH stimulation tests.
Results—In healthy dogs, serum 17-OHP concentration
frequency intervals were grouped by sex and
reproductive status (defined as < 95th percentile).
Frequency intervals of serum 17-OHP concentrations
after ACTH stimulation were < 7.7, < 2.0, < 3.2, and
< 3.4 ng/mL (< 23.3, < 6.1, < 9.7, and < 10.3 nmol/L)
for sexually intact and neutered females and sexually
intact and neutered males, respectively. In 53 dogs
with confirmed hyperadrenocorticism, serum cortisol
concentrations after ACTH stimulation and 8 hours
after administration of dexamethasone and serum 17-
OHP concentrations after ACTH stimulation were considered
borderline or abnormal in 79%, 93%, and
69% of dogs, respectively. Two of 5 dogs considered
to have atypical hyperadrenocorticism had abnormal
serum 17-OHP concentrations after ACTH stimulation.
Conclusions and Clinical Relevance—Serum 17-OHP
concentration measurement after ACTH stimulation
may be useful in the diagnosis of hyperadrenocorticism
in dogs when other test results are equivocal. (J Am Vet Med Assoc 2005;227:1095–1101)
Objective—To evaluate the effects of twice-daily oral administration of a low-dose of trilostane treatment and assess the duration of effects after once-daily trilostane administration in dogs with naturally occurring hyperadrenocorticism (NOH).
Animals—28 dogs with NOH.
Procedures—22 dogs received 0.5 to 2.5 mg of trilostane/kg (0.23 to 1.14 mg/lb) orally every 12 hours initially. At intervals, dogs were reevaluated; owner assessment of treatment response was recorded. To assess drug effect duration, 16 of the 22 dogs and 6 additional dogs underwent 2 ACTH stimulation tests 3 to 4 hours and 8 to 9 hours after once-daily trilostane administration.
Results—After 1 to 2 weeks, mean trilostane dosage was 1.4 mg/kg (0.64 mg/lb) every 12 hours (n = 22 dogs; good response [resolution of signs], 8; poor response, 14). Four to 8 weeks later, mean dosage was 1.8 mg/kg (0.82 mg/lb) every 12 or 8 hours (n = 21 and 1 dogs, respectively; good response, 15; poor response, 5; 2 dogs were ill). Eight to 16 weeks after the second reevaluation, remaining dogs had good responses (mean dosages, 1.9 mg/kg [0.86 mg/lb], q 12 h [n = 13 dogs] and 1.3 mg/kg [0.59 mg/lb], q 8 h ). At 3 to 4 hours and 8 to 9 hours after once-daily dosing, mean post-ACTH stimulation serum cortisol concentrations were 2.60 and 8.09 μg/dL, respectively.
Conclusions and Clinical Relevance—In dogs with NOH, administration of trilostane at low doses every 12 hours was effective, although 2 dogs became ill during treatment. Drug effects diminished within 8 to 9 hours. Because of potential adverse effects, lower doses should be evaluated.
Animals—5 dogs with naturally acquired diabetes
Procedure—Dogs were treated with acarbose and
placebo for 2 months each: in 1 of 2 randomly assigned
treatment sequences. Dogs that weighed ≤ 10 kg (22
lb; n = 3) or > 10 kg (2) were given 25 or 50 mg of acarbose,
respectively, at each meal for 2 weeks, then 50
or 100 mg of acarbose, respectively, at each meal for 6
weeks, with a 1-month interval between treatments.
Caloric intake, type of insulin, and frequency of insulin
administration were kept constant, and insulin dosage
was adjusted as needed to maintain control of
glycemia. Serum glucose concentrations, blood glycosylated
hemoglobin concentration, and serum fructosamine
concentration were determined.
Results—Significant differences in mean body
weight and daily insulin dosage among dogs treated
with acarbose and placebo were not found. Mean
preprandial serum glucose concentration, 8-hour
mean serum glucose concentration, and blood glycosylated
hemoglobin concentration were significantly
lower in dogs treated with insulin and acarbose, compared
with insulin and placebo. Semisoft to watery
feces developed in 3 dogs treated with acarbose.
Conclusions and Clinical Relevance—Acarbose
may be useful as an adjunctive treatment in diabetic
dogs in which cause for poor glycemic control cannot
be identified, and insulin treatment alone is ineffective.
(J Am Vet Med Assoc 2000;216:1265–1269)
Objective—To evaluate pretreatment clinical and laboratory
findings in dogs with naturally occurring primary
Animals—210 dogs with primary hyperparathyroidism
and 200 randomly selected, age-matched control dogs
that did not have primary hyperparathyroidism.
Procedure—Medical records for dogs with primary
hyperparathyroidism were reviewed for signalment;
clinical features; and results of clinicopathologic testing,
serum parathyroid hormone assays, and diagnostic
Results—Mean age of the dogs with primary hyperparathyroidism
was 11.2 years (range, 6 to 17 years). The
most common clinical signs were attributable to urolithiasis
or urinary tract infection (ie, straining to urinate,
increased frequency of urination, and hematuria). Most
dogs (149 [71%]) did not have any observable abnormalities
on physical examination. All dogs had hypercalcemia,
and most (136 [65%]) had hypophosphatemia.
Overall, 200 of the 210 (95%) dogs had BUN and serum
creatinine concentrations within or less than the reference
range, and serum parathyroid hormone concentration
was within reference limits in 135 of 185 (73%)
dogs in which it was measured. Urolithiasis was identified
in 65 (31%) dogs, and urinary tract infection was
diagnosed in 61 (29%). Mean serum total calcium concentration
for the control dogs was significantly lower
than mean concentration for the dogs with primary
hyperparathyroidism, but mean BUN and serum creatinine
concentrations for the control dogs were both significantly
higher than concentrations for the dogs with
Conclusions and Clinical Relevance—Results suggest
that urolithiasis and urinary tract infection may be associated
with hypercalcemia in dogs with primary hyperparathyroidism,
but that development of renal insufficiency
is uncommon. (J Am Vet Med Assoc 2005;227:
Objective—To determine the effects of racing and
nontraining on plasma thyroxine (T4), free thyroxine
(fT4), thyroid-stimulating hormone (TSH), and thyroglobulin
autoantibody (TgAA) concentrations in sled
dogs and compare results with reference ranges
established for dogs of other breeds.
Animals—122 sled dogs.
Procedure—Plasma thyroid hormone concentrations
were measured before dogs began and after they finished
or were removed from the Iditarod Trail Sled
Dog Race in Alaska and approximately 3 months after
Results—Concentrations of T4 and fT4 before the race
were less than the reference range for nonsled dogs in
26% and 18% of sled dogs, respectively. Immediately
after racing, 92% of sled dogs had plasma T4 concentrations
less than the reference range. Three months after
the race, 25% of sled dogs had plasma T4 concentrations
less than the reference range. For T4, fT4, TSH, and
TgAA, significant differences were not detected in samples
collected before the race versus 3 months later.
Conclusions and Clinical Relevance—Plasma T4, fT4,
and TSH concentrations decreased in dogs that complete
a long distance sled dog race. Many clinically normal
sled dogs have plasma T4 and fT4 values that are
lower than the reference range for nonsled dogs. We
suggest that the reference ranges for sled dogs are 5.3
to 40.3 nmol/L and 3.0 to 24.0 pmol/L for plasma T4 and
fT4 concentrations, respectively, and 8.0 to 37.0 mU/L
for TSH. (J Am Vet Med Assoc 2004;224:226–231)
Objective—To evaluate effects of protamine zinc
insulin (PZI) on control of glycemia in cats with newly
diagnosed diabetes mellitus or poorly controlled diabetes.
Animals—67 diabetic cats.
Procedure—34 cats with newly diagnosed diabetes
and 33 cats with poorly controlled diabetes were
treated with PZI twice daily for 45 days. Control of
glycemia was assessed on days 7, 14, 30, and 45 by
evaluation of clinical response, change in body
weight, serum fructosamine concentration, blood glucose
concentration measured 1, 3, 5, 7, and 9 hours
after administration of PZI, lowest blood glucose concentration,
and mean blood glucose concentration
during the 9-hour period after administration.
Adjustments in dosage of PZI were made as needed
to attain control of glycemia.
Results—For all cats, a significant increase in mean
dosage of PZI and significant decreases in 9-hour mean
blood glucose concentration, lowest mean blood glucose
concentration, and mean serum fructosamine
concentration were detected. For cats with poorly controlled
diabetes, 9-hour mean blood glucose concentration
and mean serum fructosamine concentration
were significantly decreased on day 45, compared with
day 0. Ninety percent of owners reported improvement
or resolution of clinical signs by day 45.
Conclusions and Clinical Relevance—Results suggest
that PZI was effective for control of glycemia in
cats with newly diagnosed or poorly controlled diabetes
and may be used as an initial treatment or as an
alternative treatment in cats that do not respond to
treatment with other types of insulin. ( J Am Vet Med
Objective—To determine prevalence of pituitary
tumors, detectable by means of computed tomography
or magnetic resonance imaging, in cats with
insulin resistance suspected to have acromegaly or
hyperadrenocorticism versus cats with well-controlled
Animals—16 cats with insulin resistance that were
also suspected to have acromegaly (n = 12) or pituitary-dependent hyperadrenocorticism (4) and 8 cats
with well-controlled diabetes mellitus.
Procedure—Computed tomography was performed
on all 16 cats with insulin resistance and 2 cats in
which diabetes mellitus was well-controlled. The
remaining 6 cats in which diabetes mellitus was wellcontrolled
underwent magnetic resonance imaging.
Images were obtained before and immediately after
IV administration of contrast medium.
Results—Computed tomography revealed a mass in
the region of the pituitary gland in all 16 cats with
insulin resistance. Maximum width of the masses
ranged from 4.4 to 12.7 mm; maximum height ranged
from 3.1 to 12.6 mm. Results of computed tomography
performed on 2 cats with well-controlled diabetes
and magnetic resonance imaging performed on the
remaining 6 cats were considered normal.
Conclusions and Clinical Relevance—Results suggest
that cats with insulin resistance suspected to
have acromegaly or pituitary-dependent hyperadrenocorticism
are likely to have a pituitary mass detectable
by means of computed tomography or magnetic resonance
imaging. (J Am Vet Med Assoc 2000;216:
Objective—To evaluate accuracy of 6 portable blood glucose meters (PBGMs) by comparing results of these meters with results obtained with a reference chemistry analyzer.
Animals—49 dogs (158 blood samples).
Procedures—Venous blood samples were tested with the 6 PBGMs, and results were compared with results of a commercially available analyzer that used a reference method based on the hexokinase reaction.
Results—Plasma glucose concentrations obtained with the reference analyzer ranged from 41 to 639 mg/dL. There were significant correlations between blood glucose concentrations obtained with the 6 PBGMs and plasma glucose concentrations obtained with the reference analyzer (r ≥ 0.96). However, for all 6 PBGMs, results differed from results for the reference analyzer, with the difference increasing as plasma glucose concentration increased. Significant differences in bias were found among meters. For 142 samples classified as hypoglycemic, euglycemic, or hyperglycemic on the basis of results of the reference analyzer, the percentage of samples that were misclassified on the basis of results of the PBGMs ranged from 2.1% to 38.7%.
Conclusions and Clinical Relevance—Results of the present study suggested that there were substantial differences in the accuracy of currently available PBGMs when used to determine blood glucose concentration in dogs.
Objective—To determine ultrasonographic characteristics of the thyroid gland in healthy small-, medium-, and large-breed dogs and evaluate the relationships of thyroid gland size and volume with body weight and body surface area (BSA).
Animals—72 dogs of small (6 Toy and 6 Miniature Poodles), medium (12 Beagles), and large breeds (12 Akitas and 36 Golden Retrievers).
Procedure—Each dog's thyroid gland was examined ultrasonographically with a 10- to 5-MHz multifrequency linear-array transducer. Size, shape, echogenicity, and homogeneity of thyroid lobes were evaluated on longitudinal and transverse images. Thyroid lobe volume was estimated by use of the equation for an ellipsoid (π/6 [length × height × width]).
Results—Thyroid lobes appeared fusiform or elliptical on longitudinal images and triangular or round to oval on transverse images. In most dogs, thyroid lobes were hyperechoic or isoechoic, compared with surrounding musculature, and had a homogeneous echogenic pattern. Mean length, width, height, and volume of thyroid lobes were significantly greater in Akitas and Golden Retrievers, compared with findings in Beagles or Poodles; mean length, width, and height were significantly greater in Beagles, compared with findings in Poodles. Total thyroid gland volume correlated with body weight (r = 0.73) and BSA (r = 0.74).
Conclusions and Clinical Relevance—Among the dog breeds examined ultrasonographically, thyroid lobe size and volume were more variable than shape, echogenicity, and homogeneity. The correlation of thyroid gland volume with BSA suggests that size of the dog, rather than breed, should be considered when assessing thyroid glands ultrasonographically.