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Objective

To evaluate clinical and laboratory findings in 225 dogs with naturally occurring hypoadrenocorticism diagnosed over a 14-year period.

Design

Retrospective case series.

Animals

220 dogs with primary hypoadrenocorticism and 5 dogs with secondary hypoadrenocorticism (primary ACTH deficiency).

Procedure

We reviewed medical records of all dogs with naturally occurring hypoadrenocorticism examined at The Animal Medical Center between 1979 and 1993 or at Tufts University, Foster Hospital for Small Animals, between 1987 and 1993.

Results

Dogs ranged from 4 months to 14 years old. Most (71%) were female, and female dogs had a significantly higher relative risk of developing hypoadrenocorticism than did males. Great Danes, Portuguese Water Dogs, Rottweilers, Standard Poodles, West Highland White Terriers, and Wheaton Terriers had a significantly higher relative risk of developing hypoadrenocorticism than did dogs of other breeds. Common owner complaints included lethargy, poor appetite, and vomiting, whereas lethargy, weakness, and dehydration were common abnormalities detected on physical examination. Serum biochemical testing at the time of diagnosis revealed moderate-to-severe azotemia and hyperphosphatemia in most dogs. In 99 of 172 (57.6%) dogs that had a pretreatment urinalysis performed, urine specific gravity was < 1.030 even though dogs were azotemic. Serum electrolyte changes included hyperkalemia (n = 215), hyponatremia (183), hypochloremia (94), and hypercalcemia (69). Five of the 220 dogs with primary hypoadrenocorticism and the 5 dogs with secondary hypoadrenocorticism did not have hyperkalemia at time of diagnosis. In all dogs, ACTH stimulation testing revealed a low to low-normal baseline serum cortisol concentration with little to no rise after ACTH administration. Endogenous plasma ACTH concentration measured in 35 dogs with primary hypoadrenocorticism was markedly high; whereas ACTH concentration was undetectable to low in the 5 dogs with secondary hypoadrenocorticism.

Clinical Implications

Hypoadrenocorticism is a rare disease in dogs, most commonly affecting young to middle-aged females; some breeds are at greater risk of developing the disease than others. In general, clinical signs are nonspecific and similar to manifestations of more common diseases. Serum electrolyte disturbances of hyperkalemia and hyponatremia are characteristic in dogs with primary hypoadrenocorticism, but concentrations may be normal in dogs with early or mild primary or secondary hypoadrenocorticism. Diagnosis of hypoadrenocorticism is best confirmed by demonstration of a low baseline serum cortisol concentration with a subnormal or negligible response to ACTH administration. Determination of endogenous plasma ACTH concentrations is valuable in differentiating primary from secondary hypoadrenocorticism, particularly in dogs with normal serum electrolyte concentrations.

Free access
in Journal of the American Veterinary Medical Association

Objective—

To determine what effects long-term phenobarbital administration to dogs with epilepsy would have on serum biochemical factors and adrenocortical function.

Design—

Prospective, uncontrolled study.

Animals—

Five dogs with idiopathic epilepsy.

Procedure—

Serum total protein, albumin, total bilirubin, and cholesterol concentrations and serum alkaline phosphatase and alanine aminotransferase activities were measured before and 2 weeks, 6 months, and 12 months after initiation of phenobarbital administration. Endogenous ACTH concentration was measured, and ACTH stimulation and low-dose dexamethasone suppression tests were performed at the same time.

Results—

Serum albumin concentration decreased in 4 of 5 dogs, and serum cholesterol concentrations decreased in all 5 dogs over the course of the study. Serum alkaline phosphatase concentration and alanine aminotransferase activities increased over time, and were greater than the upper reference limits in 4 of the 5 dogs by the end of the study. Endogenous ACTH concentration increased in all dogs but remained within reference limits. Plasma ACTH-stimulated aldosterone concentration increased over the course of the study. Plasma cortisol concentration did not suppress, after administration of dexamethasone, in 1 dog after 6 and 12 months of phenobarbital administration.

Clinical Implications—

Although endogenous acthconcentration should be normal in dogs receiving phenobarbital, results of ACTH stimulation and dexamethasone suppression tests may be altered. Serum albumin and cholesterol concentrations, and serum alkaline phosphatase and alanine aminotransferase activities may also be abnormal.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objectives

To test whether femoral ostectomy level, subtrochanteric bone mass removal, and stem-size selection significantly affect stem positioning in canine total hip replacement, and to determine ability of the femoral stem component to restore geometry of the normal femoral head and neck.

Sample Population

Femurs from 8 adult mixed-breed canine cadavers.

Procedure

Femurs were systematically prepared, using 8 combinations of 3 surgical preparation techniques that included level of ostectomy (cervical isthmus vs lesser trochanter), subtrochanteric bone block removal, and femoral stem size (recommended, undersized). Computer-aided analysis of specimen photographs was used to evaluate femoral head offset and position and variability of femoral stem positioning for each of the preparation combinations.

Results

Original femoral head offset and position were reconstructed to within a mean of 0.052 and 0.031 cm, respectively, using an undersized femoral stem after ostectomy at the level of the lesser trochanter. Implantation of an undersized femoral stem after subtrochanteric bone block removal improved ability to centralize the distal tip of the implant and reduce the angle between the femoral diaphyseal and implant axes. Ostectomy at the level of the cervical isthmus tended to force femoral implants into a varus position, and ostectomy at the level of the lesser trochanter tended to force implants into a valgus position.

Conclusions

Geometry of normal canine femurs was most closely reconstructed by implantation of an undersized femoral component after ostectomy at the level of the lesser trochanter. Implantation of an undersized femoral component after subtrochanteric bone block removal resulted in the best alignment and centralization of the stem. (Am J Vet Res 1998;59:1071–1079)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To compare effects of isoflurane and propofol on the cystometrogram and urethral pressure profile (UPP) in healthy female cats.

Animals—6 healthy female cats.

Procedures—Cats were anesthetized, and a consistent plane of anesthesia was maintained with low and high doses of isoflurane and propofol. A 6-F double-lumen urinary catheter was placed aseptically in the urethra for cystometrogram and UPP measurements. Threshold pressure and volume were recorded for cystometrograms. Maximum urethral pressure for smooth and skeletal muscle portions of the urethra, maximum urethral closure pressure, and functional profile length were measured during each UPP measurement. Heart rate and respiratory rate were recorded.

Results—Cats anesthetized with the low dose of propofol had consistent detrusor reflexes, compared with results for the other anesthetics. Mean ± SD threshold pressure, volume per unit of body weight, and compliance were 75.7 ± 16.3 cm H2O, 8.3 ± 3.2 mL/kg, and 0.5 ± 0.4 mL/cm H2O, respectively, for low-dose propofol. Anesthesia with either dose of propofol caused a significantly higher percentage change in heart rate during the cystometrogram, compared with results for anesthesia with isoflurane. Maximal urethral pressure in the area corresponding to skeletal muscle and the maximum urethral closure pressure were significantly higher for the low dose of propofol, compared with results for the high dose of propofol.

Conclusions and Clinical Relevance—The low-dose propofol regimen was the easiest to titrate and maintain and yielded diagnostic-quality detrusor reflexes in all 6 cats. Anesthetic depth should be titrated appropriately when performing urodynamic procedures.

Full access
in American Journal of Veterinary Research

Abstract

Objective

To determine the diagnostic value of full-mouth radiography in dogs.

Sample Population

Prospective series of 226 dogs referred for dental treatment without previous full-mouth radiographic views being available.

Procedure

In a prospective nested case-control analysis of multiple outcomes in a hospital cohort of dogs presented for dental treatment, full-mouth radiographic views were obtained prior to oral examination and charting. After treatment, clinical and radiographic findings were compared, with reference to presenting problems, main clinical findings, additional information obtained from the radiographs, and unexpected radiographic findings. The importance of the radiographic findings in therapeutic decision-making was assessed.

Results

The main clinical findings were radiographically confirmed in all dogs. Selected presenting problems and main clinical findings yielded significantly increased odds ratios for a variety of other conditions, either expected or unexpected. Radiographs of teeth without clinical lesions yielded incidental or clinically important findings in 41.7 and 27.8% of dogs, respectively, and were considered of no clinical value in 30.5%. Radiographs of teeth with clinical lesions merely confirmed the findings in 24.3% of dogs, yielded additional or clinically essential information in 50.0 and 22.6%, respectively, and were considered of no value in 3.1%. Older dogs derived more benefit from full-mouth radiography than did younger dogs. Incidental findings were more common in larger dogs.

Clinical Relevance

Diagnostic yield of full-mouth radiography in new canine patients referred for dental treatment is high, and the routine use of such radiographs is justifiable. (Am J Vet Res 1998;59:686-691)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To determine the diagnostic value of full-mouth radiography in cats.

Sample Population

115 cats referred for dental treatment without a previous full-mouth radiographic series available.

Procedure

In a prospective nested case-control analysis of multiple outcomes in a hospital cohort of cats referred for dental treatment, full-mouth radiography was done prior to oral examination and charting. After treatment, the clinical and radiographic findings were compared, with reference to presenting problems, main clinical findings, additional information obtained from radiography and unexpected radiographic findings. Importance of the radiographic findings in therapeutic decision making was assessed.

Results

The main clinical findings were radiographically confirmed in all cats. Odontoclastic resorption lesions, missed on clinical examination, were diagnosed in 8.7% of cats. Analysis of selected presenting problems and main clinical findings yielded significantly increased odds ratios for a variety of other conditions, either expected or unexpected. Radiographs of teeth without clinical lesions yielded incidental or clinically important findings in 4.8 and 41.7% of cats, respectively, and were considered of no clinical value in 53.6%. Radiographs of teeth with clinical lesions merely confirmed the findings in 13.9% of cats, but yielded additional or clinically essential information in 53.9 and 32.2%, respectively.

Clinical Relevance

The diagnostic yield of full-mouth radiography in new feline patients referred for dental treatment is high, and routine use of full-mouth radiography is justifiable. (Am J Vet Res 1998;59:692-695)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the in vivo response of α2-adrenoceptors to medetomidine administration in cats with feline idiopathic cystitis (FIC) during periods of stress and after environmental enrichment.

Animals—13 cats with FIC and 12 healthy cats.

Procedures—Cats were subjected to an acute-onset moderate stressor for 8 days. After stress, 20 μg of medetomidine/kg was administered IM on days 1, 3, and 8. Heart rate, blood pressure, pupil diameter, respiratory rate, and level of sedation were evaluated before and after administration of the drug. After day 8, cats were moved to an enriched environment, and tests were repeated on day 35.

Results—Heart rate decreased and pupil diameter increased significantly after medetomidine administration in healthy cats, compared with cats with FIC. Cats with FIC had significantly lower respiratory rates. No significant differences in blood pressure or sedation level were found.

Conclusions and Clinical Relevance—Increased plasma catecholamine concentrations during the enrichment phase, which have been reported elsewhere, may have contributed to the differences in α2-adrenoceptor responses detected in cats with FIC.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine concentrations of α-tocopherol in serum and CSF of healthy horses following administration of supplemental vitamin E in feed.

Animals—10 healthy adult horses.

Procedures—Horses were allocated to receive supplemental d-α-tocopherol (1,000 U/d [group A; n = 5] or 10,000 U/d [group B; 5]) in feed for 10 days. Blood samples were collected before (baseline), during, and at intervals for 10 days after discontinuation of vitamin E administration for assessment of serum α-tocopherol concentration. Cerebrospinal fluid samples were collected prior to and 24 hours after cessation of vitamin E administration. α-Tocopherol concentrations in serum and CSF samples were analyzed via high-performance liquid chromatography; changes in those values during the treatment period were compared between groups, and the relationship of serum and CSF α-tocopherol concentrations was evaluated.

Results—In both groups, serum α-tocopherol concentration increased significantly from baseline during vitamin E administration; values in group B were significantly greater than those in group A during and after treatment. At the end of vitamin E administration, CSF α-tocopherol concentration was not significantly greater than the baseline value in either group; however, the increase in CSF concentration was significant when the group data were combined and analyzed. Serum and CSF α-tocopherol concentrations were significantly correlated at baseline for all horses, but were not strongly correlated after 10 days of vitamin E administration.

Conclusions and Clinical Relevance—In healthy horses, daily oral administration of supplemental vitamin E in feed resulted in increases in serum and CSF α-tocopherol concentrations.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine frequency and types of complications, prognostic factors, and primary diseases affecting clinical outcome associated with administration of total parenteral nutrition (TPN) in cats.

Design—Retrospective study.

Animals—75 cats that received TPN for ≥ 12 hours.

Procedure—Medical records were reviewed, and information was obtained on signalment, history, problems at initial evaluation, physical examination findings, weight and changes in weight while receiving TPN, duration in the hospital before initiation of TPN, the type of TPN catheter used, duration of TPN administration, and final diagnosis. Laboratory results obtained immediately prior to TPN and at 24 and 96 hours following initiation of TPN administration were compared.

Results—Reports of weight loss at initial evaluation, hyperglycemia at 24 hours, or diagnosis of chronic renal failure were significantly associated with increased mortality rate. Greater serum albumin concentrations prior to and at 96 hours following TPN administration were significantly associated with decreased mortality rate. Mechanical and septic complications were infrequent and not associated with increased mortality rate. Most cats had multiple diseases. The overall mortality rate was 52%; among 75 cats, 36 recovered, 23 were euthanatized, and 16 died as a result of their primary illness or complications associated with their illness.

Conclusions and Clinical Relevance—Results indicated high mortality rate in cats maintained on TPN that had multiple concurrent diseases associated with a poor prognosis. Indicators of poor prognosis included a history of weight loss, hyperglycemia at 24 hours following TPN administration, hypoalbuminemia, and chronic renal failure. (J Am Vet med Assoc 2004;225:242–250)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate areas of articular contact of the proximal portions of the radius and ulna in normal elbow joints of dogs and the effects of axial load on size and location of these areas.

Sample Population—Forelimbs obtained from cadavers of 5 adult mixed-breed dogs.

Procedure—After forelimbs were removed, liquidphase polymethyl methacrylate was applied to articular surfaces of the elbow joint, and limbs were axially loaded. Articular regions void of casting material were stained with water-soluble paint. Relative articular contact areas were determined by computer-assisted image analyses of stained specimens. Repeatability of the technique was evaluated by analyses of casts from bilateral forelimbs of 1 cadaver. Incremental axial loads were applied to left forelimbs from 4 cadavers to determine effects of load on articular contact.

Results—Specific areas of articular contact were identified on the radius, the craniolateral aspect of the anconeus, and the medial coronoid process. The medial coronoid and radial contact areas were continuous across the radioulnar articulation. There was no articular contact of the medial aspect of the anconeus with the central trochlear notch. Coefficients of variation of contact areas between repeated tests and between contralateral limbs was < 20%. Significant overall effects of axial load on contact area or location were not identified.

Conclusions—Three distinct contact areas were evident in the elbow joint of dogs. Two ulnar contact areas were detected, suggesting there may be physiologic incongruity of the humeroulnar joint. There was no evidence of surface incongruity between the medial edge of the radial head and the lateral edge of the medial coronoid process. (Am J Vet Res 2000;61: 1315–1321)

Full access
in American Journal of Veterinary Research