Neuropathic pain in cats: Mechanisms and multimodal management

PRACTICAL RELEVANCE

Chronic pain is a significant welfare concern in cats, and neuropathic pain, which arises from aberrant processing of sensory signals within the nervous system, is a subcategory of this type of pain. To comprehend this condition and how multimodal pharmacotherapy plays a central role in alleviating discomfort, it is crucial to delve into the anatomy of nociception and pain perception. In addition, there is an intricate interplay between emotional health and chronic pain in cats, and understanding and addressing the emotional factors that contribute to pain perception, and vice versa, is essential for comprehensive care.Clinical approach:Neuropathic pain is suspected if there is abnormal sensation in the area of the distribution of pain, together with a positive response to trial treatment with drugs effective for neuropathic pain. Ideally, this clinical suspicion would be supported by confirmation of a lesion at this neurolocalisation using diagnostic modalities such as MRI and neuroelectrophysiology. Alternatively, there may be a history of known trauma at that site. A variety of therapies, including analgesic, anti-inflammatory and adjuvant drugs, and neuromodulation (eg, TENS or acupuncture), can be employed to address different facets of pain pathways.Aim:This review article, aimed at primary care/ general practitioners, focuses on the identification and management of neuropathic pain in cats. Three case vignettes are included and a structured treatment algorithm is presented to guide veterinarians in tailoring interventions.Evidence base:The review draws on current literature, where available, along with the author's extensive experience and research.

Gallbladder carcinoid in a cat

Carcinoids are rare tumors that originate from neuroendocrine system cells. There has apparently only been 1 report in the veterinary medical literature of a cat with a gallbladder carcinoid, with no long-term follow-up information available from that case. Furthermore, apparently only 9 dogs with gallbladder carcinoids have been reported, again with no long-term follow-up. This case report describes the clinical presentation, surgical appearance, histopathologic and immunohistochemical findings, postoperative adjuvant chemotherapy treatment, and long-term outcome of a domestic longhair cat with a gallbladder carcinoid. The diagnosis of a gallbladder carcinoid in the present case was based on histologic and immunohistochemical findings. Clinical signs of a gallbladder carcinoid are nonspecific and ultrasonographic findings may not be definitive; however, it should be considered as a potential differential diagnosis in cats with lesions of the gallbladder or in the region of the gallbladder. The prognosis is poor, with a potentially high metastatic rate. In the present case, metastasis occurred 7 mo postoperatively despite adjuvant therapy, and the survival time was only 10 mo from the time of diagnosis. Key clinical message: This case report describes the clinical presentation, surgical appearance, histopathologic and immunohistochemical findings, postoperative adjuvant treatment, and long-term outcome of a cat with a gallbladder carcinoid, which should be considered as a potential differential diagnosis in cats with lesions of the gallbladder or in the region of the gallbladder.

Importance of early diagnosis, multimodal treatment, and a multidisciplinary approach for oral eosinophilic lesions in cats: a retrospective study of 38 cases (1997-2022)

OBJECTIVE

This study aimed to characterize the clinical and histopathologic features of oral eosinophilic lesions in cats.

Animals

38 client-owned cats.

METHODS

The medical records database was searched for cats diagnosed with histologically confirmed eosinophilic oral lesions from 1997 to 2022. Information such as medical history, lifestyle factors, clinical presentation, and radiographic and histopathologic features was included for 38 client-owned cats. Response to treatment and long-term follow-up was also recorded.

RESULTS

The most affected site was the tongue, with approximately half of the affected cats showing signs of oral discomfort and difficulty eating or breathing. Ulcerative lesions were common, with two-thirds of patients showing more than 1 site affected. Histological samples had a classic appearance, whereas some had an atypical appearance characterized by degenerate collagen clusters associated with multinucleated giant cells. A significant association between lesion location, clinical signs, and prognosis was also found, with patients with palatal lesions being more likely to show respiratory signs and less likely to respond to treatment. Finally, treatment response was observed in most cases within 2 months of commencing therapy combining antimicrobial, and immunosuppressive treatment.

CLINICAL RELEVANCE

The results of this study demonstrate the importance of early diagnosis and treatment of cases of oral eosinophilic lesions in cats. Additionally, it emphasizes the need for a multimodal approach to treatment which should include antibacterial therapy. Of no less importance is that other systems may be affected in these patients, warranting a multidisciplinary approach to their management.

Corneal cross-linking (CXL)-A clinical study to evaluate CXL as a treatment in comparison with medical treatment for ulcerative keratitis in horses

OBJECTIVE

Compare CXL treatment with medical treatment alone in horses with stromal, ulcerative keratitis.

ANIMALS STUDIED

24 horses (24 eyes) with stromal, ulcerative keratitis were included.

PROCEDURE

12 horses were initially treated with CXL, and 12 horses were given conventional medical treatment. Topical medical treatment was added to horses in the CXL group if necessary. Parameters including cytology, microbial growth, time to fluorescein negativity, and time to inhibition of stromal melting were evaluated.

RESULTS

After the first day of treatments, a decrease in inflammatory signs and pain from the eye was observed in both groups. Stromal melting ceased within 24 hours regardless of treatment. CXL treatment alone was sufficient in 3 horses with noninfectious, superficial stromal ulcerations. Clinical signs of impaired wound healing were seen after 3-14 days in corneas with suspected or proven bacterial infection treated with CXL only, most likely because of insufficient elimination of bacteria deeper in the corneal stroma or because of re-infection from bacteria in the conjunctiva. The average decrease in stromal ulcer area per day after onset of treatment was almost identical between the groups, and no significant difference in time to fluorescein negativity was found.

CONCLUSIONS

We consider CXL a possible useful adjunct treatment of corneal stromal ulcers in horses, especially for melting ulcers and as a potential alternative to prophylactic antibiotic treatment for noninfected stromal ulcers. However, CXL should not be used alone for infected or suspected infected stromal ulcers, because topical antibiotics were required in all horses with proven infectious keratitis.

Intraoperative acridine orange photodynamic therapy and cribriform electron-beam irradiation for canine intranasal carcinomas: 14 cases

Canine intranasal carcinomas are almost always malignant. Surgery alone often results in rapid tumor regrowth. Radiotherapy is the treatment of choice for dogs with intranasal tumors. Here, we retrospectively assessed treatment of intranasal carcinoma by marginal tumor resection followed by intraoperative acridine orange (AO) photodynamic therapy (PDT) and cribriform plate electron-beam intraoperative radiotherapy (IORT). Fourteen canine cases were assessed, 12 of which had stage I tumors, one with stage III, and one with stage IV. Recurrence was detected in 8, with a median recurrence from the time of treatment of 6 months (range: 3 to 16 months). The median progression-free survival time and overall survival time after treatment were 13 and 22 months, respectively. Adverse events were mild. Marginal tumor resection followed by intraoperative AO-PDT and cribriform plate electron-beam IORT may increase the tumor control time in dogs with marginally resectable intranasal malignant tumors beyond that incurred by surgery alone.

A combination of electrochemotherapy, gene electrotransfer of plasmid encoding canine IL-12 and cytoreductive surgery in the treatment of canine oral malignant melanoma

The aim of this study was to evaluate the safety and efficacy of the combination of electrochemotherapy (ECT) with bleomycin and gene electrotransfer (GET) of plasmid encoding canine interleukin 12 (IL-12) for the treatment of canine oral malignant melanoma (OMM). Our focus was to determine the effect of the treatment on achieving local tumor control and stimulation of an antitumor immune response. Nine dogs with histologically confirmed OMM stage I to III were included in a prospective, non-randomized study. The dogs were treated with a combination of cytoreductive surgery, ECT and IL-12 GET, which was repeated up to five times, depending on the clinical response to the treatment, evaluated according to the follow-up protocol (7, 14 and 28 days after, the last treatment). One month after treatment, the objective response (OR) rate was 67% (6/9). Median survival time (MST) was 6 months and, even though the disease progressed in 8/9 patients at the end of the observation period (2 to 22 months), four animals were euthanized due to tumor-unrelated reasons. In addition, we observed a decline in the percentage of regulatory T cells (Treg) in the peripheral blood in the course of the treatment, which could be attributed to a systemic antitumor response to IL-12 GET. The results of this study suggest that a combination of ECT and IL-12 GET may be beneficial for dogs with OMM, especially when other treatment approaches are not acceptable due to their invasiveness or cost.

Pentoxifylline as adjunct therapy to long-term clinical management of a right-to-left patent ductus arteriosus

Management of a right-to-left ("reversed") patent ductus arteriosus (PDA) focuses on control of clinical signs associated with hyperviscosity due to erythrocytosis. Pentoxifylline therapy is presented as an adjunct to routine phlebotomies for the long-term clinical management of reversed PDA in a 10-year-old Chihuahua.

Effects of epidermal growth factor receptor kinase inhibition on radiation response in canine osteosarcoma cells

BACKGROUND

Radiation therapy is a palliative treatment modality for canine osteosarcoma, with transient improvement in analgesia observed in many cases. However there is room for improvement in outcome for these patients. It is possible that the addition of sensitizing agents may increase tumor response to radiation therapy and prolong quality of life. Epidermal growth factor receptor (EGFR) expression has been documented in canine osteosarcoma and higher EGFR levels have been correlated to a worse prognosis. However, effects of EGFR inhibition on radiation responsiveness in canine osteosarcoma have not been previously characterized. This study examined the effects of the small molecule EGFR inhibitor erlotinib on canine osteosarcoma radiation responses, target and downstream protein expression in vitro. Additionally, to assess the potential impact of treatment on tumor angiogenesis, vascular endothelial growth factor (VEGF) levels in conditioned media were measured.

RESULTS

Erlotinib as a single agent reduced clonogenic survival in two canine osteosarcoma cell lines and enhanced the impact of radiation in one out of three cell lines investigated. In cell viability assays, erlotinib enhanced radiation effects and demonstrated single agent effects. Erlotinib did not alter total levels of EGFR, nor inhibit downstream protein kinase B (PKB/Akt) activation. On the contrary, erlotinib treatment increased phosphorylated Akt in these osteosarcoma cell lines. VEGF levels in conditioned media increased after erlotinib treatment as a single agent and in combination with radiation in two out of three cell lines investigated. However, VEGF levels decreased with erlotinib treatment in the third cell line.

CONCLUSIONS

Erlotinib treatment promoted modest enhancement of radiation effects in canine osteosarcoma cells, and possessed activity as a single agent in some cell lines, indicating a potential role for EGFR inhibition in the treatment of a subset of osteosarcoma patients. The relative radioresistance of osteosarcoma cells does not appear to be related to EGFR signalling exclusively. Angiogenic responses to radiation and kinase inhibitors are similarly likely to be multifactorial and require further investigation.

Evaluation of the use of chemotherapy and other prognostic variables for surgically excised canine thyroid carcinoma with and without metastasis

This retrospective study compared the efficacy of surgery alone versus surgery in combination with chemotherapy in the treatment of canine thyroid carcinoma; potential prognostic factors were evaluated. Forty-four dogs with biopsy-confirmed thyroid carcinoma met the inclusion criteria. Twenty-eight dogs were treated with surgery alone and 16 with surgery and chemotherapy. The median survival of dogs treated with surgery and chemotherapy was 518 d, which was not statistically different from that of the dogs treated with surgery alone. The number of thyroid lobes removed at surgery was prognostic with respect to survival. Despite an overall metastatic rate of 48%, the addition of chemotherapy to surgical excision did not improve survival; however, this finding may be due to inadequate power to demonstrate a difference.

Cataracts in 44 dogs (77 eyes): A comparison of outcomes for no treatment, topical medical management, or phacoemulsification with intraocular lens implantation

Outcomes for 77 cataractous eyes were compared after each eye underwent no treatment, topical medical treatment only, or phacoemulsification with intraocular lens implantation. Median follow-up time for all dogs was 2.3 y. Failure occurred in all untreated eyes and the rate of failure was 65 and 255 times higher than in medically and surgically treated eyes, respectively. The failure rate was 4 times higher in dogs receiving only medical treatment compared with dogs that received surgery. Across all groups, the success rate for mature and hypermature cataracts was lower than for immature cataracts. Regardless of cataract stage, the chance of success was higher for eyes undergoing phacoemulsification than for eyes that received medical management only. Results of this study support prompt referral for phacoemulsification when cataracts are diagnosed in dogs or, if referral is not possible, topical anti-inflammatory therapy.

Cytokine-enhanced vaccine and interferon-β plus suicide gene as combined therapy for spontaneous canine sarcomas

Eleven soft tissue- and five osteosarcoma canine patients were subjected to: (i) periodic subcutaneous injection of irradiated xenogeneic cells secreting hGM-CSF and hIL-2 mixed with allogeneic or autologous tumor homogenates; and (ii) injections of cIFN-β and HSVtk-carrying lipoplexes and ganciclovir, marginal (after surgery) and/or intratumoral (in the case of partial tumor resection, local relapse or small surface tumors). This treatment alone (4 patients) or as surgery adjuvant (12 patients), was safe and well tolerated. In those patients presenting local disease (6/11), the suicide gene plus cIFN-β treatment induced local antitumor activity evidenced by the objective responses (3 complete, 2 partial) and stable diseases (2). In addition, the treatment prevented or delayed local relapse, regional metastases (lymph nodes developed only in 3/16) and distant metastases (0/16), suggesting a strong systemic antitumor immunity. The most encouraging result was the long survival times of 10 patients (>1 year, with good quality of life).

Non-thermal irreversible electroporation (N-TIRE) and adjuvant fractionated radiotherapeutic multimodal therapy for intracranial malignant glioma in a canine patient

Non-thermal irreversible electroporation (N-TIRE) has shown promise as an ablative therapy for a variety of soft-tissue neoplasms. Here we describe the therapeutic planning aspects and first clinical application of N-TIRE for the treatment of an inoperable, spontaneous malignant intracranial glioma in a canine patient. The N-TIRE ablation was performed safely, effectively reduced the tumor volume and associated intracranial hypertension, and provided sufficient improvement in neurological function of the patient to safely undergo adjunctive fractionated radiotherapy (RT) according to current standards of care. Complete remission was achieved based on serial magnetic resonance imaging examinations of the brain, although progressive radiation encephalopathy resulted in the death of the dog 149 days after N-TIRE therapy. The length of survival of this patient was comparable to dogs with intracranial tumors treated via standard excisional surgery and adjunctive fractionated external beam RT. Our results illustrate the potential benefits of N-TIRE for in vivo ablation of undesirable brain tissue, especially when traditional methods of cytoreductive surgery are not possible or ideal, and highlight the potential radiosensitizing effects of N-TIRE on the brain.

[Protein-losing enteropathy in Rottweilers]

OBJECTIVES

To describe the signs, histopathological features, and treatment outcome of a not previously described protein-losing enteropathy (PLE) in Rottweiler dogs.

METHODS

A retrospective study involving 17 Rottweilers referred for PLE. Data on sex, age, presenting signs, histopathological diagnosis, and treatment outcome were collected. The canine inflammatory bowel disease activity index (CIBDAI) score was calculated, to quantify disease severity. Endoscopic intestinal biopsies were evaluated according to the guidelines of the World Small Animal Veterinary Association (WSAVA) gastrointestinal standardization group.

RESULTS

Presenting signs were watery diarrhoea and weight loss. In all dogs with PLE in this study, the abnormalities found were consistent with a form of inflammatory bowel disease. Some of the dogs had a secondary infection with Giardia or Cyniclomyces guttulatus. In 10 dogs (59%) the CIBDAI score was 9 or higher, indicative of severe disease. Histopathological findings revealed lymphoplasmacellular enteritis, with lymphangiectasia in 14 (82%) dogs and eosinophil infiltration in 10 (59%) dogs. Eleven (65%) dogs were euthanized or died because of the intestinal disease. Kaplan-Meier analysis revealed a median survival time of 5 months, with a 1-year survival rate of 47%. Seven (4%) dogs were disease-free after treatment with immunosuppressants and dietary measures, but some relapsed (median disease-free interval 21 months).

CLINICAL SIGNIFICANCE

In Rottweilers presenting with chronic diarrhoea and weight loss, clinicians should consider the presence of severe PLE, which has a poor prognosis.

Necrotising fasciitis due to Prevotella bivia in a cat

A 15-year-old domestic shorthair cat was evaluated for an acute onset of jaw swelling and anorexia. A small area of skin discoloration, left mandibular subcutaneous soft swelling and dehydration were noted on physical examination. Fine needle aspirate findings of the mass were compatible with an abscess. After 8 hours of supportive and antimicrobial treatment, a large area of necrotic skin was noted. The cat was taken to surgery and an aggressive debridement was performed. The histopathology findings were compatible with necrotising fasciitis and dermatitis.

The principals of surgical oncology: surgery and multimodality therapy

Surgery to treat cancer is one of the most common procedures performed in small animal practice. Clinicians should identify potential intraoperative risk factors, such as blood loss and hypotension, and be prepared to address these complications. Of the surgical doses that can be used to resect tumors, wide resections are preferred, although marginal resection is acceptable if the tumor is sensitive to radiation and adjunctive radiation therapy is planned. Other types of surgical procedures used in oncology include preventive, palliative, and second-look procedures, as well as minimally invasive laparoscopy and thoracoscopy to assess treatment efficacy. Depending on the tumor type and metastatic potential and the completeness of excision, adjunctive radiation therapy and chemotherapy should also be considered.

Getting the elbow: diagnosis and management of elbow disease in dogs

Elbow dysplasia is a major welfare issue for medium and large-breed dogs, including Labrador Retrievers, Rottweilers and Mastiffs. It is common to see older dogs with chronic lameness and bilateral pain and stiffness of the elbow, and managing the condition is challenging. John Innes of the Small Animal Teaching Hospital at the University of Liverpool describes some recent changes in diagnosis and treatment

Problematic parasite to pet and owner

No visitor arriving at a UK air or seaport is left in any doubt about the British Government's wish to keep these islands free of rabies. But far less publicity is given to warnings about the threat posed to human health by another disease which may be carried by companion animals. John Bonner reports on the campaign to stop the fox tapeworm Echinococcus multilocularis from reaching these shores.

Electrochemotherapy compared to surgery for treatment of canine mast cell tumours

The aim of this study was to evaluate the effectiveness of local treatment electrochemotherapy (ECT) with cisplatin and to compare it with effectiveness of surgery for treatment of mast cell tumours (MCT) in dogs.

MATERIALS AND METHODS

In the present retrospective study, 25 dogs of different breeds with MCT were divided into two treatment groups: surgery (16 dogs with 16 tumours) and those whose owners refused surgery being included into the ECT group (9 dogs with 12 tumours). Response rate and duration of response to the treatment were evaluated and comparison between groups was made.

RESULTS

The clinical stages of the tumours were stage I in 4 (45%) and stage III in 5 (55%) dogs treated by ECT; 12 (75%) dogs treated by surgery were stage I and 4 (25%) dogs were in clinical stage III. The median size of the tumours was 5.2 cm3 and 2.9 cm3 of tumours treated by surgery and ECT, respectively. ECT resulted in as comparable antitumor effectiveness as surgical treatment. However, the estimated median duration of response in dogs treated with complete surgical excision was 31.5 months, while it was not reached for the ECT group at the time of writing.

CLINICAL SIGNIFICANCE

ECT is an easy, effective and safe local treatment of MCT. It can be an alternative treatment to surgery, specifically for smaller nodules in which a complete response with long duration can be obtained after only one treatment session, or when the nodule is unresectable because of the location.

Response to a combined treatment program with clomipramine, behavioral, and environmental management of compulsive tail chasing in a German Shepherd

A 15-month-old female German Shepherd dog showing compulsive tail chasing was treated with a treatment protocol of pharmacological therapy (using clomipramine) in conjunction with behavioral and environmental management. The responses to the treatment protocol were assessed once a week for 7 weeks in respects to behavioral conditions and the frequency of bouts and its duration. The behavior history including mother, father, and her littermates were also evaluated for the apparent diagnosis. The compulsive tail chasing of the patient dog was improved on the aspect of behavioral condition and gradually decreased in the frequency and duration of bouts. However, in the mid of treatment, the animal showed an aggressive behavior as a concurrent sign associated with compulsive tail chasing.

Immunoglobulin A multiple myeloma with cutaneous involvement in a dog

An 8-year-old rottweiler, diagnosed with multiple myeloma and multiple sites of cutaneous involvement, was treated with chemotherapy and radiation therapy. The diagnostic criteria for canine multiple myeloma, limitations of diagnostic testing for light chain proteinuria in dogs, and the role of radiation therapy in multiple myeloma patients is discussed.

Canine pituitary macrotumors

Pituitary macroadenomas and macroadenocarcinomas are being increasingly recognized in veterinary medicine. The term macroadenoma is poorly defined in veterinary medicine. Because pituitary imaging is not routinely performed in dogs with pituitary-dependent hyperadrenocorticism (PDH), the true incidence of pituitary macroadenomas is unknown but may range from 15% to 75% of dogs with PDH. Recent advances in endocrine testing and pituitary imaging have facilitated the detection of pituitary macrotumors, leaving routine imaging of affected patients as the last hurdle to early detection, treatment, and an improved quality of life.

Osteosarcoma in a 6-year-old Newfoundland dog: limb-sparing surgery and cisplatin chemotherapy

A 6-year-old Newfoundland dog was presented with left forelimb lameness, which was diagnosed as osteosarcoma and treated with an endoprosthetic limb-spare surgery and cisplatin chemotherapy.

Evaluation of radiotherapy alone or in combination with doxorubicin chemotherapy for the treatment of cats with incompletely excised soft tissue sarcomas: 71 cases (1989-1999)

OBJECTIVE

To determine whether the addition of doxorubicin chemotherapy affected the outcome of cats with incompletely excised, nonvisceral soft tissue sarcomas undergoing postoperative radiotherapy.

DESIGN

Retrospective case series.

ANIMALS

71 cats.

PROCEDURES

Medical records were reviewed for clinically relevant data on cats that underwent postoperative radiotherapy for treatment of incompletely excised soft tissue sarcomas with or without concurrent doxorubicin chemotherapy. Radiotherapy was performed on an alternate-day schedule, with a total dose of 58.8 to 63 Gy delivered in 21 fractions. Doxorubicin was administered every 21 days for 3 to 5 cycles. Follow-up information was obtained by means of physical examination or through telephone conversations with refer-ring veterinarians or owners.

RESULTS

Median disease-free interval with concurrent radiotherapy and doxorubicin chemotherapy (15.4 months; range, 2.4 to 44.9 months) was significantly longer than median disease-free interval with radiotherapy alone (5.7 months; range, 1.0 to 50.8 months). However, survival time was not significantly different between groups.

CONCLUSION AND CLINICAL RELEVANCE

Results suggested that doxorubicin chemotherapy may play a role in extending the disease-free interval in cats undergoing radiotherapy for treatment of incompletely excised soft tissue sarcomas.

Clinical signs, treatments, and outcome in cats with transitional cell carcinoma of the urinary bladder: 20 cases (1990–2004)

OBJECTIVE

To characterize demographics and clinical signs and evaluate outcomes of treatments in cats with transitional cell carcinoma (TCC) of the urinary bladder.

DESIGN

Retrospective case series.

ANIMALS

20 cats with TCC.

PROCEDURES

Medical records of 20 cats with a bladder mass identified as a TCC that were examined at 2 veterinary institutions between 1990 and 2004 were evaluated. Signalment, treatments, and outcome were assessed.

RESULTS

Breeds included domestic short hair (n=14), long hair (2), and medium hair (2) cats, Siamese (1), and Abyssinian (1). All cats had been neutered at an early age (< 1 year old; 13 neutered males and 7 spayed females). The median age at diagnosis of TCC was 15.2 years. The trigone region was affected in 9 cats. Treatments included piroxicam administration, chemotherapy, or surgery as single interventions or in combination; 6 cats were not treated. At the time of diagnosis, 3 cats had pulmonary metastasis and 1 cat had metastasis to local lymph nodes. Median survival time for all 20 cats was 261 days. Nearly all deaths were attributable to progressive disease in the urinary tract. Five cats were lost to follow-up.

CONCLUSIONS AND CLINICAL RELEVANCE

In cats, TCC of the urinary bladder appears to be a rare and aggressive disease that is more prevalent in male cats and frequently develops at sites distant from the trigone (unlike TCC in dogs). Nevertheless, initial clinical signs of TCC in cats in this study were similar to those reported for affected dogs.

Canine Oral Melanoma

Melanoma is the most common oral malignancy in the dog. Oral and/or mucosal melanoma has been routinely considered an extremely malignant tumor with a high degree of local invasiveness and high metastatic propensity. Primary tumor size has been found to be extremely prognostic. The World Health Organization staging scheme for dogs with oral melanoma is based on size, with stage I = <2-cm-diameter tumor, stage II = 2- to <4-cm-diameter tumor, stage III = > or = 4cm tumor and/or lymph node metastasis, and stage IV = distant metastasis. Median survival times for dogs with oral melanoma treated with surgery are approximately 17 to 18, 5 to 6, and 3 months with stage I, II, and III disease, respectively. Significant negative prognostic factors include stage, size, evidence of metastasis, and a variety of histologic criteria. Standardized treatments such as surgery, coarse-fractionation radiation therapy, and chemotherapy have afforded minimal to modest stage-dependent clinical benefits and death is usually due to systemic metastasis. Numerous immunotherapeutic strategies have been employed to date with limited clinical efficacy; however, the use of xenogeneic DNA vaccines may represent a leap forward in clinical efficacy. Oral melanoma is a spontaneous syngeneic cancer occurring in outbred, immunocompetent dogs and appears to be a more clinically faithful therapeutic model for human melanoma; further use of canine melanoma as a therapeutic model for human melanoma is strongly encouraged. In addition, the development of an expanded but clinically relevant staging system incorporating the aforementioned prognostic factors is also strongly encouraged.

Orthovoltage radiation and weekly low dose of doxorubicin for the treatment of incompletely excised soft-tissue sarcomas in 39 dogs

The efficacy and toxicity of orthovoltage radiation therapy and concurrent low doses of doxorubicin for the treatment of incompletely excised soft-tissue sarcomas in 39 dogs was investigated retrospectively. The 39 dogs had 40 soft-tissue sarcomas and received 51 Gy orthovoltage radiation in 17 daily 3 Gy fractions; they also received 10 mg/m(2) doxorubicin once a week administered intravenously one hour before the dose of radiation. The median follow-up time was 910 days. The tumours recurred locally in seven of the dogs, in five of them within the radiation field; the median time to their recurrence was 213 days (range 63 to 555 days). Six of the dogs developed a distant metastasis after a median time of 276 days (range eight to 826 days). The one-year and two- to four-year tumour control rates were 84 per cent and 81 per cent, respectively, and the one-, two- and three- to four-year survival rates were 85 per cent, 79 per cent and 72 per cent, respectively. Tumours with a mitotic rate of more than 9 per 10 high-power fields were significantly more likely to recur, and the dogs with such tumours survived for significantly shorter periods.

Ipsilateral vascularised ulnar transposition autograft for limb-sparing surgery of the distal radius in 2 dogs with osteosarcoma

Canine osteosarcoma is the most commonly diagnosed primary bone tumour in the dog, affecting mainly large and giant breed dogs with the predilection site being the metaphysis of long bones, specifically the distal radius, proximal humerus, distal femur and proximal tibia and fibula. Treatment options are either palliative or curative intent therapy, the latter limb amputation or limb-sparing surgery together with chemotherapy. This article describes the use of an ipsilateral vascularised ulnar transposition autograft as well as chemotherapy in 2 dogs with osteosarcoma of the distal radius. Both dogs showed minimal complications with the technique and both survived over 381 days following the surgery. Complications seen were loosening of the screws and osteomyelitis. The procedure was well tolerated with excellent limb use. This technique is indicated for use in cases with small tumour size that have not broken through the bone cortex.

INTRALESIONAL CISPLATIN CHEMOTHERAPY AND TOPICAL CRYOTHERAPY FOR THE CONTROL OF CHOANAL SQUAMOUS CELL CARCINOMA IN AN AFRICAN PENGUIN (SPHENISCUS DEMERSUS)

A 3.5-yr-old, 2.5-kg female African penguin (Spheniscus demersus) was diagnosed with a choanal squamous cell carcinoma on the basis of biopsy after a history of choanal ulceration and anorexia with weight loss. Therapeutic modalities included the use of intralesional cisplatin followed by localized, topical cryotherapy with liquid nitrogen. The penguin remained free of clinical disease for a period of 9 mo, at which time a second cryotreatment was performed. The patient has remained free of all signs of choanal carcinoma for a period of 13 mo since the second cryotreatment.

Effects of caloric restriction and a moderate or intense physiotherapy program for treatment of lameness in overweight dogs with osteoarthritis

OBJECTIVE

To evaluate the effects of a weight reduction program combined with a basic or more complex physical therapy program including transcutaneous electric nerve stimulation on lameness in overweight dogs with osteoarthritis.

DESIGN

Nonblinded prospective randomized clinical trial. Animals-29 adult overweight or obese dogs with a body condition score of 4/5 or 5/5 and clinical and radiographic signs of osteoarthritis.

PROCEDURES

A weight-loss program was initiated for all dogs. One group received caloric restriction and a home-based physical therapy program. The other group received the identical dietetic protocol and an intensive physical therapy program including transcutaneous electrical nerve stimulation. Lameness was assessed clinically and by kinetic gait analysis on a treadmill with 4 force plates to measure symmetry of ground reaction forces (GRFs) of the affected and contralateral limbs in bimonthly intervals for 6 months.

RESULTS

Significant weight loss was achieved in both groups; however, greater weight reduction was attained by dogs treated with caloric restriction and intensive physiotherapy. Mobility and symmetry indices of GRFs were improved after 6 months; the best outcome was detected in the group receiving energy restriction combined with intensive physical therapy.

CONCLUSIONS AND CLINICAL RELEVANCE

Caloric restriction combined with intensive physical therapy improved mobility and facilitated weight loss in overweight dogs. The combination of dietetic and physical therapy may help to improve the health status more efficiently than dietetic treatment alone.

Changes in tumour oxygenation during fractionated hyperthermia and radiation therapy in spontaneous canine sarcomas

Tumour oxygenation was measured in seven canine soft tissue sarcomas being treated with a fractionated course of radiation and hyperthermia. Measurements obtained during treatment were compared to pre-treatment measurements. The most important finding was an increase in oxygenation in tumours with low pre-treatment oxygenation that persisted throughout treatment. This is an advantageous hyperthermia effect as it may lead to increased radiation cell killing at each fraction. In other tumours, potentially less advantageous changes in oxygenation may be hyperthermia fractionation related and this deserves further investigation.

Multiple limbal haemangiosarcomas in a border collie dog: management by lamellar keratectomy/sclerectomy and strontium-90 beta plesiotherapy

An eight-year-old, neutered, male border collie dog was presented with a six-week history of left ocular discomfort and a raised, red mass at the lateral limbus. The right eye had been enucleated approximately 12 months previously following suspected trauma when the eye had become red and painful. The mass was excised using superficial keratectomy/sclerectomy and the surgery site was treated with strontium-90 beta radiation. Histopathological findings were consistent with a diagnosis of haemangiosarcoma. Immunohistochemical staining showed uniform expression of CD31 in neoplastic cells, confirming their endothelial origin. Two further treatments with strontium-90 beta radiation were applied to the surgical site at weekly intervals. Twenty-six weeks after surgery, a second, raised, red limbal mass became apparent at the medial limbus of the left eye. Surgical excision and adjuvant strontium-90 beta plesiotherapy were performed as described for the initial tumour. Routine histopathological analysis confirmed haemangiosarcoma at this site. Eighty-six weeks following the initial presentation, no recurrence of ocular haemangiosarcoma was evident.

Intermandibular malignant mesenchymoma in a crossbreed dog

A 12-year-old German shepherd crossbreed dog was presented with a submandibular mass that was initially diagnosed as myxosarcoma on incisional biopsy. Chest radiographs were taken for staging, and magnetic resonance imaging was performed to assess the feasibility of cytoreductive surgery before adjuvant radiotherapy. The dog underwent debulking surgery, and histology permitted reclassification of the tumour as a malignant mesenchymoma (with myxosarcomatous and osteosarcomatous differentiation). The dog was subsequently treated with four fractions of radiotherapy given at seven-day intervals and three doses of carboplatin. The dog remained stable following therapy until its condition acutely deteriorated, and it was euthanased 153 days after surgery. On postmortem examination, there were no signs of local tumour recurrence, but metastases were observed both in the thorax and in the abdomen.

Efficacy of using an internal teat sealer to prevent new intramammary infections in nonlactating dairy cattle

OBJECTIVE

To determine whether insertion of an internal teat sealer (ITS) at the end of lactation would prevent development of new intramammary infections (IMIs) during the nonlactating period.

DESIGN

Controlled clinical trial.

ANIMALS

939 Holstein-Friesian dairy cows from 16 herds.

PROCEDURES

Results of bacteriologic culture of milk samples collected 14 days prior to the end of lactation were used to assign cows to groups (group 1 = negative results for all quarters; group 2 = positive results for > or = 1 quarter). Quarters of cows in group 1 were treated with an ITS or a single intramammary dose of cloxacillin; quarters of cows in group 2 were treated with cloxacillin in conjunction with an ITS or with cloxacillin alone. Milk samples were collected at the end of lactation and within 8 days after calving.

RESULTS

Regardless of whether the outcome of interest was new IMIs caused by any pathogens, major pathogens, environmental pathogens, or streptococci other than Streptococcus agalactiae, quarters in group 2 treated with both cloxacillin and an ITS were less likely to develop a new IMI than were quarters treated with cloxacillin alone. For cows in group 1, no significant difference in risk of new IMIs was found between treatments.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that for dairy cattle with an IMI late in the lactation period, intramammary administration of cloxacillin at the end of lactation followed by insertion of an ITS enhanced protection against development of new IMIs, compared with use of cloxacillin alone.

Canine limbal melanoma: 30 cases (1992-2004). Part 2. Treatment with lamellar resection and adjunctive strontium-90beta plesiotherapy - efficacy and morbidity

OBJECTIVES

To evaluate the efficacy of lamellar resection and adjunctive 90Sr-beta plesiotherapy in the management of canine limbal melanoma and the frequency and morbidity of early and late-onset side effects following treatment.

DESIGN

Retrospective study.

ANIMALS STUDIED

Thirty dogs treated for limbal melanoma at the Animal Health Trust (AHT), between 1992 and 2004.

METHODS

Medical records were reviewed and information collected on the radiation dose administered, duration of follow-up, and the frequency of early- and late-onset ocular side effects. Follow-up information was obtained by re-examination of patients or completion of a telephone interview with the referring veterinary surgeons or the owners.

RESULTS

Recurrence of limbal melanoma occurred in 1 of 30 cases (3%; 95% CI: 0.2-14%). One or more side effects occurred in 16 of 30 cases (53%; 95% CI: 28.1-74.9). The occurrence of side effects was not associated with the number of sites treated or the total surface dose of radiation. Short-term side effects were reported in 16/30 cases (53%) and included corneal scarring (12/30), corneal neovascularization (6/30), conjunctivitis with or without granulation tissue formation (5/30), lipid keratopathy (1/30), and localized bullous keratopathy (2/30). Long-term side effects were reported in 6 of 30 cases (20%) cases and included deep scleral thinning (5/30), focal scleromalacia (3/30), globe perforation (2/30), lipid keratopathy (3/30), localized bullous keratopathy (1/30), and sectoral cortical cataract (1/30).

CONCLUSIONS

Lamellar resection and adjunctive 90Sr-beta plesiotherapy is relatively easy to perform, is minimally invasive, and extremely well tolerated by patients. The treatment is highly efficacious in the management of canine limbal melanoma. Modification of the radiation dosimetry, in particular reducing the total dose of radiation and the dose per radiation fraction, is necessary to reduce the incidence of late onset side effects.

Role of carboplatin in multi-modality treatment of canine tonsillar squamous cell carcinoma - a case series of five dogs

Canine tonsillar squamous cell carcinoma is an aggressive disease with a poor prognosis. A retrospective study was undertaken of all dogs that were presented between January 1999 and January 2004 to the Animal Health Trust for the treatment of tonsillar squamous cell carcinoma. Five cases were identified, and their median survival time was 211 days (95 per cent confidence interval 80 to 352) with two of the five dogs remaining alive at the end of the study, 826 and 1628 days from diagnosis with no clinical signs of disease. The protocol was well tolerated with only one of the five dogs showing toxicity associated with carboplatin and all dogs that started radiotherapy completing it. Compared with results of previous studies, these cases suggest that surgical cytoreduction followed by coarse fractionated radiotherapy together with carboplatin may be a useful way to treat this tumour. Carboplatin alone caused partial remission in the two cases where it was used as neo-adjunctive therapy.

Cystic endometrial hyperplasia-pyometra complex in cats. A review

Presentation of complex cystic endometrial hyperplasia-pyometra is not very common in cats. As in bitches, hormonal influences result in environmental and histological changes in the uterus leading to predisposition to bacterial growth. Its influence on the organism provokes certain clinical signs. Diagnosis and treatment must be fast and aggressive. Depending on the clinical status and queen purpose, it can be both surgical or medical. Both of them offer a high rate of success if the detailed protocols are followed.

Systemic Therapies for Joint Disease in Horses

Systemic therapies for joint disease may be prescribed when a single joint is involved or when multiple sites are affected. The precise therapeutic regimen recommended depends on the duration,cause, and site(s) of injury and is often an adjunct to intra-articular or supportive therapies. If the clinical signs of joint disease are acute and moderate in severity, nonsteroidal anti-inflammatory drugs are often administered to alleviate pain and inflammation. When aiming for more of a generalized maintenance or chondro-protective regimen, an alternative medication, such as hyaluronan,polysulfated glycosaminoglycan, or a nutraceutical will commonly be prescribed.

Outcome of accelerated radiotherapy alone or accelerated radiotherapy followed by exenteration of the nasal cavity in dogs with intranasal neoplasia: 53 cases (1990-2002)

OBJECTIVE

To compare long-term results of radiotherapy alone versus radiotherapy followed by exenteration of the nasal cavity in dogs with malignant intranasal neoplasia.

DESIGN

Retrospective study.

ANIMALS

53 dogs with malignant intranasal neoplasia.

PROCEDURE

All dogs underwent radiotherapy consisting of administration of 10 fractions of 4.2 Gy each on consecutive weekdays. For dogs in the surgery group (n=13), follow-up computed tomography was performed, and dogs were scheduled for surgery if persistent or recurrent tumor was seen.

RESULTS

Perioperative complications for dogs that underwent surgery included hemorrhage requiring transfusion (2 dogs) and subcutaneous emphysema (8). Rhinitis and osteomyelitis-osteonecrosis occurred significantly more frequently in dogs in the radiotherapy and surgery group (9 and 4 dogs, respectively) than in dogs in the radiotherapy-only group (4 and 3 dogs, respectively). Two- and 3-year survival rates were 44% and 24%, respectively, for dogs in the radiotherapy group and 69% and 58%, respectively, for dogs in the surgery group. Overall median survival time for dogs in the radiotherapy and surgery group (477 months) was significantly longer than time for dogs in the radiotherapy-only group (19.7 months).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that exenteration of the nasal cavity significantly prolongs survival time in dogs with intranasal neoplasia that have undergone radiotherapy. Exenteration after radiotherapy may increase the risk of chronic complications.

Outcome of dogs with high-grade soft tissue sarcomas treated with and without adjuvant doxorubicin chemotherapy: 39 cases (1996-2004)

OBJECTIVE

To examine the effect of adjuvant doxorubicin chemotherapy on outcome in dogs with high-grade (grade 3) soft tissue sarcomas (HGSTSs).

DESIGN

Retrospective case series.

ANIMALS

39 dogs.

PROCEDURES

Medical records of dogs with HGSTSs were reviewed. Dogs treated with surgery alone or receiving single-agent doxorubicin chemotherapy postoperatively were included in the study. Owners and referring veterinarians were contacted for follow-up information. Slides from histologic sections were reviewed to confirm the diagnosis of HGSTSs. Cases in which follow-up examination was not performed and radiation therapy or chemotherapy other than doxorubicin was administered were excluded.

RESULTS

39 dogs met inclusion criteria. Twenty-one dogs received adjuvant doxorubicin. Tumor-, patient-, and treatment-related variables were not significantly associated with measured outcomes including local, metastatic, and overall disease-free intervals as well as survival time. Overall median disease-free interval was 724 days with a median survival time of 856 days for all dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Adjuvant doxorubicin-based chemotherapy did not benefit this population of dogs with HGSTSs. Outcome for visceral HGSTSs was similar to that of nonvisceral HGSTSs in these cases.

Chip fractures from the distal lateral trochlear ridge of the talus of a quarter horse gelding: a veterinary medicine clinical report

An eighteen-month old quarter horse gelding was diagnosed with chip fractures from the distal lateral trochlear ridge of the talus. The horse presented with the symptom of persistent synovitis. The diagnosis was based on radiographic evidence. The horse was treated initially with arthroscopic surgery. He was given a non-steroidal anti-inflammatory agent, and a chondroprotective agent to prevent further damage to, and aid in the healing of, the damaged joint.

Treatment of bilateral corneal ulceration in a Peregrine Falcon (Falco peregrinus) using 360 degree conjunctival flaps

A wild Peregrine Falcon (Falco peregrinus) was presented with extensive bilateral fluorescein positive corneal damage. Local therapy and bilateral tarsorrhaphies resulted in slow improvement over 5 weeks. When bilateral 360 degree conjunctival flaps were used subsequently, healing proceeded more rapidly over the next 8 weeks. Although bulbar conjunctival flaps have been reported as difficult in birds due to their small size and relatively immobile bulbar conjunctiva, 360 degree conjunctival flaps made from palpebral rather than bulbar conjunctiva were found to be technically feasible in a larger bird species such as the Peregrine Falcon.

Synovial fluid changes in induced infectious arthritis in calves

The objective was to develop an experimental model of septic arthritis in calves and to evaluate the effect of treatment on cytologic and bacteriologic variables of synovial fluid. The right tarsus of 7 healthy Holstein bull calves were inoculated with 10⁸ colony‐forming units of viable Escherichia coli of a pap‐positive strain (day 1). On day 2, joint lavage was performed and antibiotic treatment was instituted. Cytologic examinations, bacterial cultures, and pap factor determinations by polymerase chain reaction (PCR) were performed on synovial fluid samples that were collected daily until day 4, then every 4 days until day 24. Results of physical examination, the severity of lameness, and swelling were recorded. Clinical signs of septic arthritis appeared on day 2 and persisted until day 9 for all calves. Bacterial cultures from all calves were positive for E coli on day 2, and remained positive until day 3 for 1 calf and until day 4 for 5 calves. In addition, PCR results were positive for all calves, with 6 positive through day 3 and 1 positive through day 4, after which a positive result was again obtained on day 24. Synovial fluid neutrophil counts and white blood cell counts were significantly increased on days 2–4; however, synovial total protein concentrations were increased (P < .05) throughout the experiment in comparison to day 1. Results of all bacterial cultures were negative on day 8, although clinicopathologic signs of inflammation persisted until day 20. This model successfully induced acute septic arthritis in calves. Rapid recovery occurred within 1 week when an appropriate treatment was instituted early in the course of the disease

Quantitative comparison of three commonly used treatments for navicular syndrome in horses

OBJECTIVE

To quantitatively compare 3 commonly used treatments for navicular syndrome (NS) in horses: heel-elevation shoeing alone, heel-elevation shoeing and phenylbutazone administration, heel-elevation shoeing and injection of the distal interphalangeal joint (DIPJ) with triamcinolone acetonide (TA), and all 3 treatments in combination.

ANIMALS

12 horses with NS.

PROCEDURE

A force plate was used to measure baseline peak vertical ground reaction force (PVGRF) of the forelimbs. Each horse's forelimbs were shod with 3 degrees heel-elevation horseshoes; PVGRF was measured 24 hours and 14 days after shoeing. Fourteen days after shoeing (following data collection), phenylbutazone (4.4 mg/kg, i.v., q 12 h) was administered (5 treatments). Two hours after the fifth treatment, PVGRF was measured; TA (6 mg) was injected into the DIPJ of the forelimb that generated the lower baseline PVGRF Fourteen days later, PVGRF was measured. Phenylbutazone was administered as before, and PVGRF was measured. Percentage body weight of force (%BWF) was calculated from PVGRF measurements and used for comparisons.

RESULTS

14 days after shoeing, mean %BWF in both forelimbs significantly increased from baseline; additional administration of phenylbutazone significantly increased %BWF applied from the more lame forelimb. Compared with shoeing alone, there was no significant change in %BWF after injection of the DIPJ with TA in shod horses.

CONCLUSIONS AND CLINICAL RELEVANCE

Heel-elevation shoeing alone and in combination with phenylbutazone administration quantitatively decreased lameness in horses with NS. Although not significant, additional DIPJ injection with TA resulted in further quantitative decrease in lameness, compared with that achieved via shoeing alone.