Transdermal application of methimazole in hyperthyroid cats
Felicitas Boretti and others, University of Zurich, Switzerland
Hyperthyroidism is the most common endocrine disorder of older cats and is readily diagnosed by measuring thyroxine levels, as serum total T4. While radio-iodine is the recommended treatment option, there are limited facilities offering this option and some clinicians may opt for medical management.
The authors describe a study of the efficacy and safety of a transdermal formulation of the thyroid hormone synthesis inhibitor methimazole designed for those cats that are difficult to pill. The agent, contained in a lecithin-based gel, was applied to the inner surface of the pinna at a daily dose of between 1 and 15mg in 60 cats with newly diagnosed hyperthyroidism. Follow-up ranged from four to nearly 90 months during which all cats had a significant decrease in median T4 concentrations but several cats repeatedly had T4 concentrations in the thyrotoxic or hypothyroid range.
Although transdermal methimazole is a safe and effective treatment, it can prove difficult to keep serum T4 concentrations within the reference range and owner compliance needs to be carefully monitored.
Journal of Feline Medicine and Surgery 16 (6): 453-459.
Selective serotonin reuptake inhibitor toxicosis in 33 cats
Cassandra Pugh and others, Ocean State Veterinary Specialists, East Greenwich, Rhode Island
Selective serotonin reuptake inhibitors are a class of compounds used widely in the treatment of depression in humans. They are one of the most common human medications that are accidentally ingested by cats, causing clinical signs including sedation, gastrointestinal disturbances and central nervous system stimulation. The authors document the clinical features of 33 cases of SSRI toxicosis in cats. Only eight of the 33 cases showed significant clinical signs and these were treated with a range of therapies including intravenous fluids, activated charcoal, anti-arrhythmic agents, methocarbamol, cyproheptadine, anti-emetics and sedation. The prognosis for these animals was excellent.
Journal of Veterinary Emergency and Critical Care 23 (5): 565-570.
Methocarbamol infusion for symptomatic treatment of pyrethroid intoxication
William Draper and others, University of Florida
Pyrethroids are naturally occurring compounds effective in controlling arthropod parasites. However, products designed for use in dogs can be toxic for cats and some dogs may also experience intoxication through improper use or accidental ingestion. The authors describe the use of a constant rate infusion of methocarbamol for the control of muscle tremors in two cats and one dog that had received a permethrin-based product. The tremors and all other clinical signs of pyrethroid poisoning resolved within a few hours in each case and there was no evidence of adverse drug effects.
Journal of the American Animal Hospital Association 49 (5): 325-328.
Clinical features of cutaneous lymphoma of the tarsus in 23 cats
Holly Burr and others, Tufts University, Massachusetts
Lymphoma is a common neoplastic disease in feline patients but it is relatively unusual for an animal to present with cutaneous masses. The authors examined the clinical records from 23 cases of cutaneous lymphoma affecting the tarsus, seen at a number of institutions. Most were older cats, with a median age of 12 years, and there was no association with a retrovirus positive status. Popliteal lymph node involvement was confirmed in eight cases and suspected in a further three. Thirteen cases were reported to have secondary masses at the time of last follow-up, euthanasia or death. The median survival time was 190 days.
Journal of the American Veterinary Medical Association 244 (12): 1,429-1,434.
Effects of pioglitazone on insulin sensitivity and serum lipids in obese cats
Melissa Clark and others, University of Illinois
Pioglitazone is a member of the thiazolidinedione group of oral insulin sensitisers used in the treatment of human type 2 diabetes. That condition is clinically similar to the most common form of feline diabetes and the authors investigate the response to this agent in obese cats, predisposed to insulin resistance. Twelve cats aged five to seven years old received either 1 or 3mg/kg pioglitazone or placebo given daily for seven weeks in a three-way crossover trial.
Cats receiving the higher dose showed significantly improved insulin sensitivity, reduced insulin area under the curve in an intravenous glucose tolerance test, lowered serum triglyceride and cholesterol. There was no evidence of any adverse reactions to the treatment.
Journal of Veterinary Internal Medicine 28 (1): 166-174.
Trial of intravesical glycosaminoglycans for obstructive feline idiopathic cystitis
Allison Bradley and Michael Lappin, Colorado State University
Feline idiopathic cystitis is a common condition involving haematuria and the development of plugs which may block the urethra. A defective glycosaminoglycan layer lining the urinary bladder has been proposed as both a cause and effect of FIC. The authors report a pilot study involving the infusion of a commercially available glycosaminoglycan product into the bladder of cats with urethral obstruction. None of the nine glycosaminoglycan-treated cats developed a repeat obstruction during the seven-day follow up period; three of the seven cats receiving placebo did develop another urethral plug.
Journal of Feline Medicine and Surgery 16 (6): 504-506.
Absorption of transdermal and oral cyclosporine in healthy cats
Rose Miller and others, Dermatology for Animals, Salt Lake City, Utah
Cyclosporine is commonly used to treat feline dermatoses but due to the difficulties in administering oral medications it is sometimes given in a transdermal formulation. The author investigated the blood cyclosporine concentrations in healthy cats receiving the agent via each delivery route. Median concentrations on the seventh day of treatment were 2,208ng/ml two hours after oral administration of cyclosporine and 37ng/ml at the same time following transdermal treatment. So although transdermal administration produced measurable concentrations of the agent, these only reached therapeutic levels in one of six cats treated.
Journal of the American Animal Hospital Association 50 (1): 36-41.
Comparison of blood pressure values with Doppler ultrasound and direct measurements
Anderson da Cunha and others, Louisiana State University
Accurate blood measurements are essential for monitoring anaesthesia, critically ill animals and response to therapy. Direct blood pressure measurements are considered the gold standard but the procedure is technically challenging, uncomfortable for the patient and unsuitable for many clinical situations. The authors compare the accuracy of direct measurements with those achieved using the ultrasonic Doppler flow detector method. Their results suggest that there is poor agreement between directly measured blood pressure and Doppler values in anaesthetised cats and use of the latter in this species is not recommended.
Veterinary Emergency and Critical Care 24 (3): 272-278.
Changes in vaginal cytology after induction of oestrus in cats
Halit Kanca and others, Ankara University, Turkey
Vaginal cytology is routinely used to assess the stage reached in the oestrus cycle of bitches. The technique is used much less frequently in cats because the cellular changes are more ambiguous and due to the differences in mating behaviour in the two species. The authors examined the vaginal cytology of queens after induction of oestrus by repeated artificial vaginal stimulation and the administration of gonadotropin-releasing hormone. They found that induction of oestrus results in an increase in the mean proportion of intermediate cells and a significant decrease in dimensions and red-green-blue values of vaginal epithelial cells.
Australian Veterinary Journal 92 (3): 65-70.
In vitro effects of glycoprotein IIb/IIIa receptor antagonists on platelet aggregation
Aliya Magee and others, Purdue University, Indiana
Cardiogenic embolism occurs in a high proportion of cats with underlying cardiac disease and is associated with significant mortality. The glycoprotein IIb/IIIa receptor complex is a key target for therapies designed to prevent platelet activation and clot formation. The authors describe the effects of a GP IIb/IIIa antagonist eptifibatide on the platelets of healthy cats. It caused a significant reduction in platelet aggregation in vitro. Although unsuitable on safety grounds as a therapeutic agent, the compound may be useful as the basis of an in vitro platelet inhibitory assay to identify cats with hyper-reactive platelets.
American Journal of Veterinary Research 75 (3): 309-312.
Comparison of rectal and axillary temperature measurements in cats and dogs
Joana Goic and others, University of Pennsylvania
Accurate assessment of body temperature forms an important part of most physical examinations of veterinary patients. Axillary measurements are sometimes used as a substitute for standard rectal measurements although data from human studies suggest that the correlation is often unsatisfactory.
The authors compared rectal and axillary measurements in 94 dogs and 31 cats. Their findings confirm that while
axillary temperature measurements are convenient, they do not reliably reflect rectal temperatures in either species and they cannot be recommended as a replacement method.
Journal of the American Veterinary Medical Association 244 (10): 1,170-1,175.
Management of cats and dogs with endotracheal tube tracheal foreign bodies
Laura Nutt and others, Veterinary Emergency Clinic South, Toronto, Ontario
Even with close monitoring it is possible for a patient under general anaesthesia to recover more quickly than anticipated. On rare occasions this may result in damage to the endotracheal tube and possible aspiration of the damaged portion.
The authors describe the clinical findings in two feline and three canine cases treated for an endotracheal tube foreign body in the trachea during recovery from general anaesthesia. In each case the object was removed using bronchoscopy and the patient was clinically normal at discharge.
Canadian Veterinary Journal 55 (6): 565-568.
