DIURETIC RENAL SCINTIGRAPHY IN NORMAL DOGS

Diuretic renal scintigraphy is commonly used in human medicine to differentiate obstructive from nonobstructive pyelectasia. In order to determine normal parameters, 99mTc-DTPA renal scintigraphy was performed twice in 20 healthy adult Mongrel dogs. Each dog was injected with either 3.0 mg/kg furosemide or an equivalent volume of saline 4.5 min following injection of the radiopharmaceutical. The following parameters were evaluated: (1) global and individual glomerular filtration rate (GFR); (2) time of peak (TOP) of the time-activity curve (TAC); (3) shape of the TAC; (4) individual kidney excretion half-time (T1/2); (5) proportion of maximum activity measured at end of study (8 min); (6) time of onset; and (7) duration of the effect of the diuretic. Most TAC in the diuretic renography group showed a steep drop in the curve following administration of the diuretic compared with a gradual slope in the saline control group. There was a statistically significant difference in T1/2 between the control renograms (median 10.25 min, range 4.41-18.07 min) and the diuretic renograms (median 4.16 min, range 3.62-5.90 min). There was a statistically significant difference in percentage maximum activity between the control renograms (median 65.25%, range 48.27-93.68%) and the diuretic renograms (median 48.54%, range 35.64-58.76%). Median time of onset of the diuretic effect was 1.10 min (0.20-2.40 min), and median duration was 0.83 min (0.30-2.35 min).     

Effects of delmadinone acetate on pituitary-adrenal function, glucose tolerance and growth hormone in male dogs

Objective To characterise the effects of delmadinone acetate on the pituitary-adrenal axis, glucose tolerance and growth hormone concentration in normal male dogs and dogs with benign prostatic hyperplasia.
Design A prospective study involving nine normal male dogs and seven with prostatic hyperplasia.
Procedure Delmadinone acetate was administered to six normal male dogs and seven dogs with benign prostatic hyperplasia at recommended dose rates (1.5 mg/kg subcuta-neously at 0, 1 and 4 weeks). Three normal controls received saline at the same intervals. Blood concentrations of ACTH, cortisol, glucose, insulin and growth hormone were measured over 50 days. Intravenous glucose tolerance and ACTH response tests were performed before and after treatment in the nine normal animals.
Results A substantial suppression of basal and 2 h post-ACTH plasma cortisol secretion was demonstrated after one dose in all dogs given delmadinone acetate. Individual responses after the second and third administration varied between recovery in adrenal responsiveness to continued suppression. Plasma ACTH concentration was also diminished after one treatment. No effects were evident on glucose tolerance or serum growth hormone concentrations.
Conclusion Delmadinone acetate causes adrenal suppression from inhibition of release of ACTH from the pituitary gland. Treated dogs may be at risk of developing signs of glucocorticoid insufficiency if subjected to stressful events during or after therapy. Neither glucose intolerance nor hyper-somatotropism seems likely in male dogs given delmadinone acetate at the recommended dose rate, but the potential for excessive growth hormone secretion in treated bitches remains undetermined.     

Plasma cortisol responses to three cortico-trophic preparations in normal dogs

Objective To compare cortisol responses to three corticotrophic preparations in normal dogs.
Animals Eight clinically normal dogs (four intact males, four intact females) of medium size.
Procedures Each dog received four treatments on four separate occasions in a duplicated Latin square pattern. Treatments were two adrenocorticotrophin (ACTH) preparations given intramuscularly at 2.2 U/kg, one of the ACTH preparations given intramuscularly at 1 U/kg and a synthetic polypeptide with ACTH-like activity (tetracosactrin, cosyntropin) given intravenously at 5 μg/kg. Plasma samples were taken for cortisol assay before and at 0.5, 1, 2 and 4 h after treatment.
Results Plasma cortisol concentrations were similar with the two ACTH preparations and at both dose rates. Tetracosactrin produced smaller mean peak cortisol concentrations, which tended to occur earlier than with ACTH, and smaller values for the area under the curve of plasma cortisol concentration from zero time to 4 h.
Conclusion The findings suggest that canine adrenal function can be tested adequately by giving ACTH intramuscularly at 1 U/kg and measuring plasma cortisol in samples taken at 0 and 2 h, or by giving tetracosactrin intravenously at 5 μg/kg and determining cortisol concentration at 0 and 1 h.     

Transient glucose malabsorption in two horses fact or artefact?

Two horses, presented for investigation of chronic weight loss despite normal to increased feed intake, had flat oral glucose absorption curves, suggesting malabsorption. The cause of the apparent malabsorption was not evident grossly or on light microscopic examination of the intestinal tract. Both horses survived long term and at follow-up examination had regained weight and their capacity to absorb glucose. These cases illustrate that flat glucose absorption curves may occur in horses with no obvious intestinal lesions, that they may revert to normal and that the results of these tests should be interpreted with caution.     

Nasopharyngeal cryptococcosis

Naturally occurring cryptococcosis in five cats, a dog and a koala is described. Involvement of the nasopharynx was documented in all patients, and nasopharyngeal mass lesions accounted for the major presenting complaints in four. Signs referable to nasopharyngeal disease included snoring, stertor, inspiratory dyspnoea and aerophagia. Diagnoses were made by caudal rhinoscopy using a retroverted flexible endoscope, vigorous orthograde flushing with saline, or at necropsy. Concurrent cryptococcal rhinitis was present in all cases, although involvement appeared limited to the caudal nasal cavity in most cases. Typical signs of nasal cavity disease, such as sneezing and nasal discharge, were often absent. Treatment of nasopharyngeal cryptococcosis should include physical dislodgement or debulking of lesion(s) to provide immediate alleviation of upper airway obstruction, followed by systemic antifungal therapy to eliminate residual infection from the nasal cavity. Infections caused by Cryptococcus neoformans var gattii accounted for a disproportionately large number of these cases.     

Use of anti-inflammatory and analgesic drugs in dogs and cats

SUMMARY: Responses (486) were collated from a survey of 5054 Australian veterinarians on their use of anti-inflammatory and analgesic drugs in dogs and cats. Almost all respondents used glucocorticoids (usually prednisolone) to treat allergic, pruritic dermatoses in dogs, while two-thirds also gave fatty acid supplements and one-half used antihistamines. Almost 60% of respondents initially injected a glucocorticoid (frequently a long-acting preparation) when treating inflammatory skin diseases in dogs. More than 90% of respondents used glucocorticoids to treat immunemediated haemolytic anaemia or thrombocytopenia, and about one-third also gave cytotoxic drugs. Administration of prednisolone on alternate days was generally favoured for long-term enteral steroid therapy. Phenylbutazone was the most preferred treatment for painful or inflammatory musculoskeletal disorders of dogs, but aspirin and pentosan polysulphate were also used widely. Regarding the use of analgesics drugs generally, both narcotic analgesics and non-steroidal anti-inflammatory drugs (NSAIDs) were used more widely in dogs than in cats, but alpha-2 agonists were used similarly in both species. The most commonly used narcotic analgesics were pethidine and buprenorphine in both species, while the NSAIDs used most often were flunixin and dipyrone in dogs and ketoprofen in cats. More than 80% of respondents generally used analgesic drugs with potentially painful surgical procedures, with doses given usually before anaesthetic recovery. Analgesic use rates varied with the condition, ranging from 94% for patients with acute severe trauma, through 60% for cruciate ligament repair and 29% for perineal herniorrhaphy, to about 5% for ovariohysterectomy and dog castration. The three clinical signs most frequently nominated as indicators of pain in dogs and cats were (in descending order) vocalisation, response to handling or palpating the affected area, and mental depression. Other items mentioned frequently were behavioural changes and immobility (in both species), inappetence/anorexia in cats, and altered respiration in dogs.     

Weight loss in cats which eat well

Four cats were investigated because they lost weight while eating well. One cat was found to have hypoinsulinaemic diabetes mellitus, and another had maldigestion caused by exocrine pancreatic atrophy. An enteropathy with presumed intestinal malabsorption was diagnosed in the third case. The fourth cat had hyperthyroidism and disseminated amyloidosis. The diabetic animal has been maintained satisfactorily on daily insulin injections for 2 ½ years, but treatment in the other three cases was either unsuccessful or not attempted. Weight loss is uncommon in cats which are eating well. In investigating this syndrome, it is suggested that initially urine should be tested for glucose and faeces examined for maldigestion or malabsorption. More specific tests for diabetes mellitus, pancreatic maldigestion, intestinal malabsorption or hyperthyroidism might then be indicated.     

Hypothyroidism in the dog: a retrospective study of sixteen cases

Sixteen dogs with confirmed hypothyroidism were reviewed. The diagnosis was based on subnormal plasma thyroxine concentration and poor response following TSH administration. Common clinical signs were alopecia (12 dogs), lethargy (11) and obesity (11). Plasma cholesterol concentrations were abnormally high in 10 of 14 cases tested, five of 12 were anaemic and three of five had increased creatine phosphokinase activity. Skin changes compatible with endocrinopathy were present in all five cases biopsied. Spontaneous muscle activity was found on electromyography in four cases so examined. All dogs were treated with sodium levothyroxine, and 10 of 13 for which information was available responded satisfactorily.     

Effect of Prosthesis Number and Position on Rima Glottidis Area in Equine Laryngeal Specimens

Objective— To assess the effect of 1 or 2 laryngeal prosthetic sutures on rima glottidis areas in equine laryngeal specimens. Study Design— Experimental, randomized design. Animals— Cadaveric equine larynges (n=16). Methods— Larynges were collected from 10 horses; 2 sutures each were preplaced in the right and left sides of each larynx. A dorsal suture (DS) was placed through the caudal rim of the dorsal midline of the cricoid cartilage, under the cricopharyngeus muscle and through the proximal and rostral aspect of the muscular process. A lateral suture (LS) was placed 1.5 cm lateral to the DS and through the muscular process more distal and caudal to the 1st suture. Larynges were positioned in a customized stand and the rima glottidis photographed after each suture (LS or DS) or suture combination (CS) was tied in random sequence. An additional 6 larynxes were used to determine whether the tension applied to the sutures was repeatable. Sutures were preplaced in both the right and left side of each larynx as described above and each suture and CS was tied and released 3 times in each larynx. Photographs were taken of the rima glottidis after each suture or CS was tied generating 3 replicates for each suture configuration on each side of the 6 larynges. Results— Mean rima glottidis area was not different between DS and LS when tied alone (P=.85); however, mean area after CS (DS+LS) was greater than DS (P<.001) and LS (P<.001) alone. The coefficient of variation for the 6 suture patterns were low (1–7%) and the intraclass correlation coefficient estimates were very high (0.997–0.998) demonstrating excellent repeatability between replicates for each of the 3 suture configurations. Conclusion— Our results suggest that laryngoplasty using 2 prostheses; 1 placed dorsally in the cricoid and through the rostral and proximal muscular process and 1 placed 1.5 cm lateral to the 1st and more caudal and distal in the muscular process results in a greater cross sectional area of the rima glottidis than either suture used alone. Clinical Relevance— Seemingly prosthetic sutures contribute independently to each other in determining the contour of the rima glottidis. Use of 2 prosthetic sutures improves crosssectional area of the rima glottidis compared with each suture alone and may improve surgical outcome in laryngoplasty.