Radiation therapy in two cats with pituitary tumors

Two cats with large pituitary neoplasms (adenoma and adenocarcinoma) were treated with fractionated radiation therapy. Total doses of 40 Gy, respectively 36 Gy, were applied in 10 fractions of 4 Gy, and 3.6 Gy respectively. Side effects were minimal and transient. Anesthesia was well tolerated. Improvement of clinical signs could be observed during radiation therapy in both cats. One cat had a complete, the other a partial tumor response. One cat (suspicion of adenoma) was euthanized 1 3/4 years after therapy due to unrelated disease. No tumor was found on histopathology, however a small focal necrosis of brain tissue in the irradiated field was observed. The second animal with a pituitary adenocarcinoma was euthanized because of tumor recurrence 1 1/2 years after therapy. Radiation therapy was effective, despite the low total doses of radiation applied.     

Utilization of continuous renal replacement therapy in a case of feline acute renal failure

Objective: To introduce and investigate the application, efficacy, and potential clinical complications of a continuous renal replacement therapy (CRRT) in a feline acute renal failure (ARF) patient. Case summary: A domestic short‐haired cat presented for continued management of ARF of a presumed toxic etiology. Severe azotemia and uremic complications had been identified on initial presentation to a local urgent care facility, and the cat had been referred for renal replacement therapy following approximately 9 hours of conservative management. Continuous venovenous hemodiafiltration was performed over an approximately 25‐hour period, and a significant resolution of the cat's uremic derangements was obtained. Major complications included significant hypothermia and a single episode of hypocalcemia associated with utilization of citrate anticoagulation. All complications identified were readily managed. Following hospital discharge, long‐term medical support was not required, and no evidence of significant illness was noted 6 months following therapy. New or unique information provided: CRRT represents a collection of extracorporeal blood purification techniques that utilize extended treatment periods for gradual, physiologically balanced correction of uremic toxicity. These therapies demonstrate significant promise in the treatment of ARF cats with actual or potential hemodynamic compromise, and prior advances in therapeutic administration have made these techniques readily accessible within the intensive care unit setting.     

Insulin therapy in cats with diabetes mellitus

Thirteen cats with diabetes mellitus were evaluated. Clinical signs included polydipsia, polyuria, polyphagia, lethargy, and weight loss. Results of physical examination included obesity, hepatomegaly, mild seborrhea sicca, muscle wasting, and dehydration. One cat walked plantigrade and was suspected of having a diabetic neuropathy. Persistent hyperglycemia, glucosuria, high liver enzyme activities, hypercholesterolemia, hyperproteinemia, and low electrolyte concentrations were the common laboratory findings. In 3 cats diabetes mellitus developed after megestrol acetate therapy; 2 of these cats required only temporary insulin treatment. In a 3rd cat, which had no history of receiving diabetogenic drug therapy, remission of diabetes mellitus also was observed. Serum insulin and plasma glucose concentrations were determined in 6 cats after administration of an intermediate-acting insulin (isophane insulin) and in 3 cats after administration of a long-acting insulin (protamine zinc insulin). The insulin concentration peaked 2 to 6 hours after the injection of intermediate-acting insulin and 6 to 12 hours after the injection of long-acting insulin. The lowest glucose concentration was recorded 4 to 8 hours after injection of intermediate-acting insulin, and 6 to 12 hours after injection of long-acting insulin. It was concluded that, although insulin therapy must be adjusted to the individual, the diabetic cat usually requires twice-daily administration of isophane insulin; however, the protamine zinc insulin can be given once daily for satisfactory control.     

Some effects of short-term methylprednisolone therapy in normal cats.

Four normal cats were treated weekly for 4 weeks with repositol methylprednisolone. Hemograms, serum chemistry panels, urinalyses, 24 hour water consumption, physical and constitutional parameters, and blood cortisol responses to ACTH stimulation were monitored before and during a day were done prior to steroid therapy on each cat. Clinicopathologic abnormalities induced by steroid therapy were, on the whole, inconsistent and minor. The most important findings were: (1) marked steroid-induced suppression of blood cortisol responses to ACTH, and (2) a circadian rhythm of blood cortisol production that was opposite to that of humans and dogs.     

Feline hyperthyroidism: spectrum of clinical presentions and response to carbimazole therapy

OBJECTIVE: To determine the spectrum of clinical presentations of hyperthyroidism in cats and response to carbimazole therapy by analysis of historical, clinical and laboratory data. DESIGN: A prospective clinical study involving client-owned cats presenting to a private veterinary practice in Australia. PROCEDURE: Twenty-five cats diagnosed as hyperthyroid during a 23-month period participated in the study with owner consent. Therapy with carbimazole was instituted and revisits were scheduled 2, 6 and 13 weeks after diagnosis. The cats were physically examined and underwent haematological and serum biochemical testing at each revisit. Owners were also asked to assess clinical signs in their cats in the periods between veterinary examinations. Cats with underlying renal disease were managed by alterations or cessation of carbimazole therapy. RESULTS: A high prevalence of lethargic or inappetent cats without detectable underlying nonthyroidal illness was found. There was also a high prevalence of cats less than 10-years-old and cats in good body condition. Fourteen cats treated with carbimazole and monitored for 13 weeks responded favourably to therapy. Side-effects were minor and uncommon. Cats with underlying renal disease that became apparent during the study, responded well to alterations or cessation of carbimazole therapy. CONCLUSION: The trend towards more subtle clinical presentations of hyperthyroid cats reported previously continued in this study. The findings of the current study do not appear to support the traditional view of hyperthyroid cats as being old, hyperactive, hungry and thin. Carbimazole therapy was found to decrease the prevalence of almost all clinical abnormalities in 14 cats and side-effects were minor and uncommon. This study demonstrates the usefulness of medical management of hyperthyroidism in the cat when radioiodine therapy is not possible due to renal compromise or other factors.     

Feline pyoderma therapy

Feline pyoderma is a disease entity more prevalent than previously described. Diagnosis is made by finding bacteria in the presence of inflammatory cells or bacterial phagocytosis on routine cytological examination. Diseases leading to secondary bacterial pyoderma include allergic and inflammatory skin diseases, parasitosis, feline chin acne, and others. Lesions of feline pyoderma are variable and include crusted and eroded papules, pustules, furuncles, eroded to ulcerated plaques with variable exudation and crusting, and linear to nodular ulcerative granulomatous lesions. Three cases of feline pyoderma responsive to antimicrobial therapy are discussed: case 1, a 10.5-year-old male neutered domestic short hair with eosinophilic lip ulcer, case 2, a 7-year-old male neutered domestic short hair with multiple cutaneous eosinophilic plaques, and case 3, an 8-month-old male neutered domestic short hair cat with Pseudomonas dermatitis, vasculitis, and panniculitis. Antibiotic selection for treatment of feline pyoderma should be based on cytological examination, and culture and sensitivity in unresponsive cases.     

Suspected relative adrenal insufficiency in a critically ill cat

Objective: To describe a case of likely relative adrenal insufficiency (RAI) in a cat with critical illness. Case summary: A cat recovering from polytrauma developed hypotension unresponsive to intravenous fluid support and vasopressor therapy. An adrenocorticotropin hormone stimulation test documented insufficient adrenal function. Treatment with exogenous low‐dose glucocorticoids in addition to standard therapies resulted in rapid hemodynamic and clinical improvement. The cat ultimately recovered and was weaned from supplemental glucocorticoids. New or unique information provided: This is the first report of changes consistent with acquired RAI in a cat with critical illness.     

Lower respiratory tract infections in cats: reaching beyond empirical therapy

PRACTICAL RELEVANCE: Lower respiratory tract infections (LRTIs) in cats can be due to bacteria, parasites, fungi and viruses. This review details the practical investigation of these infections and highlights specific therapy where possible. The aim is to avoid the all-too-frequent temptation in practice to treat cats with lower respiratory tract signs empirically for feline bronchial disease (FBD)/asthma. This is potentially hazardous as immunosuppressive therapy for FBD/asthma could exacerbate disease due to a LRTI. Empirical treatment of suspected LRTI is also difficult to recommend given the wide range of potential pathogens. CLINICAL CHALLENGES: Making a clinical ante-mortem diagnosis of LRTI in a cat can be challenging. Consistent historical, clinical, haematological and radiographic abnormalities are often lacking and findings may be non-specific. Astute clinical acumen, thorough investigation and high quality laboratory analysis are usually required for a diagnosis. Bronchoalveolar lavage, if feasible, and tests for lungworm should be routine in cats with lower respiratory tract signs. Lung fine needle aspiration may be useful in cases of diffuse or nodular pulmonary disease. Histopathology is rarely employed in ante-mortem investigations. EVIDENCE BASE: The authors have reviewed a substantial body of literature to provide information on many of the reported bacterial, parasitic, fungal and viral pathogens, including some that occur in Asia. Attention has been given to specific therapy for each pathogen, with evidence-based comments when there is a deviation from routine recommendations.     

A case of recurrent feline idiopathic cystitis: The control of clinical signs with behavior therapy

Feline idiopathic cystitis (FIC), is the most common medical cause of elimination change in the cat, and hence is an important differential when working up cats presenting with inappropriate elimination. A recent case-control study found that case cats were more likely than the control population to be male, overweight, and pedigreed, but the study also found that several stress factors were “flare factors” associated with the onset of a bout of clinical signs. A 5-year-old male, neutered, domestic shorthaired cat presented with recurrent bouts of dysuria and hematuria. A full medical work up eliminated other causes, leading to the diagnosis of FIC. On behavioral assessment, the cat was found to be one of 6 within the household. He showed no signs of regarding any of the other cats as part of his social group. A program of behavior therapy was instituted, which involved ensuring the patient had a separate “core area” and easy access to important resources. In addition, visual access to cats from outside the household was restricted. The cat was followed up for a period of 7 months. There was no further recurrence of clinical signs for 6 months, after which clinical signs returned. Further investigation revealed that this outbreak occurred 2 days after the owner confined the cats in close proximity again. This case provides an interesting example of how bouts of clinical signs in FIC cats can often be linked to specific “stressful” events, and how such outbreaks can be reduced or prevented through the implementation of a specific program of behavior therapy.     

Steroid injection therapy in a feline solitary bone cyst

A nine months old Japanese domestic cat with a solitary bone cyst, which is a benign tumor-like lesion and is particularly uncommon in feline practice was referred. Radiographic examination revealed an expansive radiolucency in the distal metaphysis of the right ulna and pathologic fracture. The histological examination demonstrated immature osteogenesis consisting of osteoblasts surrounded by connective tissue. We applied drainage and instillation of steroid solution into the cystic cavity. Clinical signs, including lameness and pain, disappeared three weeks after the therapy started. Fourteen months after the therapy, the cystic lesion of bone was remodeling successfully without re-developing. We conclude that our procedure was useful treatment in this case.     

Positive effects of hyperbaric oxygen therapy in a cat with cutaneous nocardiosis

Hyperbaric oxygen therapy (HBOT) has been beneficial in treating people with nocardiosis. This report describes Nocardia spp. affecting a cat, with lesions confined to the skin. To the best of the authors’ knowledge, this is the first report of HBOT, combined with amikacin, used to successfully treat feline cutaneous nocardiosis.     

Radioactive iodine therapy for feline hyperthyroidism: Efficacy and administration routes

The efficacy of radioactive iodine (¹³¹I) administration was studied in a series of 50 hyperthy-roid cats. The dose administered to each cat was based on the clinical severity of the thyrotoxicosis, the serum total thyroxine (TJ concentration and the size of the goitre estimated by palpation. The activity ranged from 80 to 200 MBq (mean ± SD, 143 ± 24 MBq}. The ¹³¹I was injected intravenously in 27 cases and subcutaneously in 23 cases. Each cat was hospitalised for 30 days after the injection. Regardless of the route of injection, none of the cats exhibited any side effects after therapy and all tolerated the hospitalisation period well. There was a significant (P<0.001) decrease in the serum total T₄ concentration (reference range, 10.4 to 42.0 nmol/litre) from a mean ± SD of 181.3 ± 111.4 nmol/litre (range, 43.8 to 575.6 nmol/litre) to a mean ± SD of 19.0 ± 29.6 nmol/litre (range, 2.0 to 175.7 nmol/litre) 30 days following the injection of the radioisotope. Five cats remained hyperthyroid, although in each case the serum total T₄ concentrations had decreased from pre-treatment values. Two of the cats subsequently became euthyroid within three and five months of therapy, respectively, two were lost to adequate follow-up and the remaining cat was successfully retreated four months later. Before treatment, four of these cases had high scores based on the three criteria used for dose estimation. Serum total T₄ concentrations below the reference range developed after treatment in many cases, but were often transient. Clinical evidence of hypothyroidism was not apparent in any cat. Recurrence of hyperthyroidism has not occurred in follow-up periods of up to 32 months. There was no difference in the outcome between the cats injected intravenously or subcutaneously and the latter was considered to be safer and simpler. The administration of an approximated dose of ¹³¹I proved to be an effective treatment for hyperthyroidism in 47 (94.0 per cent) of the cats and obviated the need for sophisticated nuclear computer facilities. There may be a lag period in some cases before euthy-roidism is achieved and this should be considered before the administration of a second dose. ¹³¹I can be administered subcutaneously without untoward effects.     

Feline aortic thromboemboli and the potential utility of thrombolytic therapy with tissue plasminogen activator

Feline aortic thromboembolism is a common and devastating clinical condition for which there is presently no effective therapy. Thrombolytic therapy with tissue plasminogen activator represents a promising, relatively noninvasive method for resolution of the clinical syndrome. In clinical trials in man, tissue plasminogen activator is proving to have advantages over previously available thrombolytic agents. Previously available thrombolytic agents require intensive monitoring and commonly cause complications that entail large monetary and manpower costs to monitor and control. Being specific for thrombus-associated plasminogen, t-PA enables more safe and effective thrombolysis without the hazards previously associated with thrombolytic therapy. In cats with aortic thromboemboli, early clinical trials are promising with regard to acute thrombolytic efficacy but raise questions concerning the risks and benefits of therapy and will require more controlled studies. It is estimated that t-PA therapy for a cat with aortic thromboemboli will cost approximately +500 to +1500, including hospitalization and drugs. This compares favorably with what most veterinary clients are willing to spend for quality veterinary care. However, before we can look upon t-PA therapy as a useful therapeutic advance, we must consider the etiopathogenesis and probability of rethrombosis. The results of controlled studies have not been published, but it is generally considered that there is a high probability of recurrence in cats. Fifty per cent of cats treated with t-PA have rethrombosed despite aspirin therapy at the recommended dose of 25 mg per kg every third day. Finding a cure for feline myocardial diseases (cardiomyopathies) and/or an effective method for safely anticoagulating cats at risk would help justify the monetary and manpower costs associated with thrombolytic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Resistance to a triple combination of broad-spectrum anthelmintics in naturally-acquired Ostertagia circumcincta infections in sheep

Extract

To the veterinary practitioner, the challenge of managing a cat with renal failure is very real. The specific goals of therapy are to:     

Partial Right Ventriculectomy Using the Incised Patch Technique to Treat Double Chambered Right Ventricle and Chylothorax in a Cat

Objective— To report successful surgical treatment of double chambered right ventricle (DCRV) in a cat.
Study Design— Clinical report.
Animals— Cat with DCRV.
Methods— DCRV was diagnosed in a 5-month-old male Maine Coon cat using echocardiography and angiocardiography. At 2 years, despite medical therapy, chylothorax developed. A section of the right ventricular free wall that spanned the fibromuscular obstruction was excised under total venous inflow occlusion (TVIO) using the incised pericardial patch technique.
Results— Short-term recovery was complicated by return of chylothorax but this resolved after thoracocentesis and diuretic therapy. Three years after surgery, the cat is free of clinical signs and no longer on any medical therapy.
Conclusions— Partial right ventriculectomy can be performed under TVIO through an incised pericardial patch.
Clinical Relevance— DCRV in cat can be successfully treated by partial right ventriculectomy performed under TVIO through an incised pericardial patch.     

Hypofractionated radiation therapy of oral melanoma in five cats

Five cats with melanoma involving the oral cavity were treated with hypofractionated radiation therapy (RT). Cobalt photons were used to administer three fractions of 8.0 Gray (Gy) for a total dose of 24 Gy. Four cats received radiation on days 0, 7, and 21 and one cat received radiation on days 0, 7, and 13. One of the cats received additional irradiation following the initial treatment course. Two cats received chemotherapy. Their age ranged from 11 to 15 years with a median age of 12 years. Three cats had a response to radiation, including one complete response and two partial responses. All five cats were euthanized due to progression of disease, with one cat having evidence of metastatic disease at the time of euthanasia. The median survival time for the five cats was 146 days (range 66-224 days) from the start of RT. The results of this study suggest that oral melanoma in cats may be responsive to hypofractionated RT, but response does not seem to be durable.     

Myasthenia gravis associated with thymic neoplasia in a cat

Objective: To describe acute myasthenia gravis (MG) in the postoperative period following removal of a thymoma in an adult cat. Case summary: A 6‐year‐old spayed female domestic short haired cat weighing 6.4 kg was referred for workup and treatment of a cranial mediastinal mass. Thoracoscopic biopsies confirmed the diagnosis of thymoma. Median sternotomy was performed and approximately 95% of the mass was surgically excised. Postoperatively the cat became remarkably weak and hypercapneic. A presumptive diagnosis of MG was made following a positive response to edrophonium injection (Tensilon test). An elevated serum acetylcholine receptor antibody level was consistent with a diagnosis of MG. Initial treatment consisted of neostigmine, followed by corticosteroids and pyridostigmine. The cat responded well to therapy. New or unique information provided: This report describes a rare syndrome of postoperative weakness due to development of MG following incomplete removal of a thymoma. Post‐thymectomy weakness associated with MG has been reported in dogs and is not well described in cats.     

Photodynamic therapy for the treatment of intranasal tumors in 3 dogs and 1 cat

Three dogs and 1 cat with intranasal tumors were treated with pyropheophorbide-a-hexyl ether-based photodynamic therapy (PDT). PDT was well tolerated by all the animals, and no adverse effects from photosensitizer injection, such as cutaneous photosensitization, were observed. Facial swelling was observed in all animals after each PDT treatment but resolved spontaneously within 72 hours after treatment. All animals had a decrease in severity of epistaxis, frequency of sneezing, and amount of nasal discharge after PDT. Clinical signs were controlled for variable time, although long-term responses were comparable with radiation therapy in 2 animals. This small case series demonstrates another application for PDT in veterinary medicine. On the basis of these findings. further studies are warranted to define the role of PDT in the management of intranasal tumors in dogs and cats.     

Radiation therapy for long-term control of odontogenic tumours and epulis in three cats.

Orthovoltage radiation was used to treat odontogenic tumours in three cats following incomplete surgical resection. Cats received a total radiation dose of 48-52 Gy over a period of 26-29 days. Acute toxicities were mild, consisting of hair loss within the radiation field in all cats, and mild mucositis in one cat. All cats had long-term (>35 months) control of their tumour, and two cats are still alive without recurrence of tumour 60 and 39 months, respectively, after completing treatment. Radiation therapy should be considered to be an adjuvant to incomplete surgery in cats with odontogenic neoplasms or epulides.     

Electrochemotherapy treatment for bilateral pleomorphic rhabdomyosarcoma in a cat

A 13-year-old male neutered cat was presented for the sudden growth of two nodular lesions close to the upper eyelid of both eyes. Fine-needle aspiration cytology was suggestive of mesenchymal neoplasia. The cat had conservative surgical excision in order to preserve the eyelids’ functionality; however, the histopathological report came with a diagnosis of incompletely excised bilateral pleomorphic rhabdomyosarcoma. Due to the local aggressiveness of this neoplasm, the cat was treated with two sessions of cisplatin-based electrochemotherapy, delivered 14 days apart. Systemic or local toxicities were not detected during the whole course of therapy. The cat is still in complete remission after 12 months. Electrochemotherapy is a safe and efficacious adjuvant therapy for aggressive sarcomas and warrants further investigations in order to standardise its protocols.