Malassezia dermatitis and otitis

The incidence of dermatitis and otitis resulting from overgrowth of M. pachydermatis is great enough that cytological sampling techniques should be considered a routine part of the dermatological examination. Because most cases of MD and Malassezia otitis cannot be grossly distinguished from bacterial pyoderma and otitis, respectively, efficiency in performing cytology testing of skin and ear canal exudate is essential to the successful diagnosis and management of pruritic skin diseases and otitis. Although Malassezia infections are rarely primary, therapy can be instituted to remove the yeast as a confounding factor while a differential diagnosis is pursued in evaluating the underlying disease process.

Tumour cell kinetics as predictors of response in canine lymphoma treated with chemotherapy alone or combined with whole body hyperthermia

Kinetic parameters including potential doubling time (Tpot), duration of S phase (Ts), labelling index (LI), and DNA index (DI) were obtained from 42 dogs with previously untreated lymphoma. Standard flow cytometric techniques using BrdUrd were employed. All dogs were treated with L-asparaginase and remission was induced in 26 dogs, which were then randomized to receive chemotherapy only (doxorubicin [DOX] alone or with lonidamine) or chemotherapy plus whole body hyperthermia (WBH). Dogs were treated every 3 weeks for up to five treatments and evaluated every 3 weeks for evidence of tumour recurrence. Within this subset of animals there was no difference in outcome based on treatment group. Median values for Tpot, Ts and LI were 3.4 days, 7.23 h and 12.49%, respectively. Dogs that had tumours with LI > or = 20% had a shorter time until recurrence than dogs with tumours characterized by LI < 20%. In dogs treated only with chemotherapy, dogs bearing tumours with longer than median Tpot and Ts values and lower than median LI had significantly longer remission duration than dogs with more rapidly proliferating tumours. Dogs treated only with chemotherapy, which had longer than median Tpot and Ts values and lower than median LI, had significantly longer remission duration than all other dogs in the study. The mechanisms in which kinetics are associated with response to chemotherapy are not clear and vary depending on tumour type and treatment regimen. More work is needed to understand factors involved in cell killing during in vivo hyperthermia.

Use of blood and blood products

It is sometimes necessary for the practitioner to transfuse the ruminant with whole blood or plasma. These techniques are often difficult to perform in practice, are time-consuming, expensive, and stressful to the animal. Acute loss of 20% to 25% of the blood volume will result in marked clinical signs of anemia, including tachycardia and maniacal behavior. The PCV is only a useful tool with which to monitor acute blood loss after intravascular equilibration with other fluid compartments has occurred. An acutely developing PCV of 15% or less may require transfusion. Chronic anemia with PCV of 7% to 12% can be tolerated without transfusion if the animal is not stressed and no further decline in erythrocyte mass occurs. Seventy-five percent of transfused bovine erythrocytes are destroyed within 48 hours of transfusion. A transfusion rate of 10 to 20 mL/kg recipient weight is necessary to result in any appreciable increase in PCV. A nonpregnant donor can contribute 10 to 15 mL of blood/kg body weight at 2- to 4-week intervals. Sodium citrate is an effective anticoagulant, but acid citrate dextrose should be used if blood is to be stored for more than a few hours. Blood should not be stored more than 2 weeks prior to administration. Heparin is an unsuitable anticoagulant because the quantity of heparin required for clot-free blood collection will lead to coagulation defects in the recipient. Blood cross-matching is only rarely performed in the ruminant. In field situations, it is advisable to inject 200 mL of donor blood into the adult recipient and wait 10 minutes. If no reaction occurs, the rest of the blood can probably be safely administered as long as volume overload problems do not develop. Adverse reactions are most commonly seen in very young animals or pregnant cattle. Signs of blood or plasma transfusion reaction include hiccoughing, tachycardia, tachypnea, sweating, muscle tremors, pruritus, salivation, cough, dyspnea, fever, lacrimation, hematuria, hemoglobinuria, collapse, apnea, and opisthotonos. Intravenous epinephrine HCl 1:1000 can be administered (0.2 to 0.5 mL) intravenously or (4 to 5 mL) intramuscularly (preferable) if clinical signs are severe. Pretreatment with antipyretics and slowing the administration rate may decrease the febrile response. Blood or plasma administered too rapidly will also result in signs of cardiovascular overload, acute heart failure, and pulmonary hypertension and edema. Furosemide and slower administration of blood or plasma should alleviate this problem. Administration rates have been suggested starting from 10 mL/kg/hr; faster rates may be necessary in peracute hemorrhage. Plasma should be administered when failure of absorption of passive maternal antibody has occurred or when protein-loosing enteropathy or nephropathy results in a total protein of less than 3 g/dL or less than 1.5 g albumin/dL. Plasma can be stored at household freezer temperatures (-15 to -20 degrees C) for a year; coagulation factors will be destroyed after 2 to 4 months when stored in this manner. To maintain viability of coagulation factors, plasma must be stored at -80 degrees C for less than 12 months. When administering plasma, a blood donor set with a built-in filter should always be used. When bovine plasma is thawed, precipitants form in the plasma and infusion of these microaggregates may result in fatal reactions in the recipient.

Suspected myelinolysis following rapid correction of hyponatremia in a dog

A dog developed signs of neurological dysfunction five days after rapid correction of severe electrolyte derangements, including hyponatremia, caused by gastrointestinal parasitism (i.e., trichuriasis). History, laboratory findings, and onset of neurological signs following correction of hyponatremia led to a diagnosis of myelinolysis. Myelinolysis is a noninflammatory, demyelinating brain disease caused by sudden, upward osmotic shifts in central nervous system plasma, often a result of rapid correction of chronic hyponatremia. The pathogenesis is complex, but recovery is possible. Iatrogenic damage due to myelinolysis can be avoided by adherence to therapeutic guidelines for correction of chronic hyponatremia.

[The percutaneous drainage of prostatic abscesses in the dog]

INTRODUCTION

Prostatic abscesses are an uncommon finding in the dog; they are most frequently seen in dogs over six years old, often in association with benign hyperplasia. Ultrasonography (US) is an essential technique to study prostatic conditions in the dog, because the particular anatomical site of this gland in the dog makes rectal palpation insufficient to assess even macroscopic changes. Presently, US-guided drainage makes a particularly efficient tool for treatment of this condition in these patients. We report on our personal technique of percutaneous drainage of prostatic abscesses in the dog.

MATERIAL AND METHODS

Forty-five dogs of different breeds and age were examined. Some of them were given short anesthesia or mild sedation for restraining purposes, although this procedure is painless and could be performed under local anesthesia like in human patients. In man, the approach is perineal, but in the dog it is best to use an abdominal approach with right or left inguinal positions. US is necessary for correct drainage of the abscess and for monitoring throughout the procedure.

DISCUSSION AND CONCLUSION

US-guided percutaneous drainage of prostatic abscesses in the dog proved to be a safe and quick tool providing excellent results. No patients exhibited any postoperative complication and we had as little as 10% relapses at 30 days. The following drainage with alcoholization of the abscessual cavity resolved the conditions definitively. This technique was particularly interesting for both its success rate and the lack of postoperative complications, which are usually quite common after conventional surgery.

Diagnosis and management of canine claw diseases

The diagnostic workup for canine claw disease consists of a good history and complete clinical examination which may provide clues for a possible underlying disorder. In dogs with claw disease but no other clinical or historical signs, further recommended diagnostic procedures include cytological evaluation of impression smears or discharge from the claw fold, bacterial culture and sensitivity testing, biopsy of the claw matrix, and an elimination diet for 6 to 8 weeks. If no underlying disease can be identified, trial treatment with essential fatty acid supplementation, vitamin E, or a combination of doxycycline hydrochloride and niacinamide may be useful. In some patients, onychectomy of all claws may be considered.

Vertebral physitis with epiphyseal sequestration and a portosystemic shunt in a Pekingese dog

Vertebral physitis with bone sequestration and a portosystemic shunt were diagnosed in an 18-month-old female Pekingese dog. The latter was determined by the presence of low blood urea nitrogen, elevated serum bile acids, microhepatica and an increased portosystemic shunt fraction. It was managed with a home-cooked low protein diet. Vertebral physitis and bone sequestration was diagnosed by the presence of thoracolumbar hyperaesthesia, radiographic and scintigraphic changes, isolation of Staphylococcus intermedius from blood and the third lumbar vertebra, and histopathological examination of a surgical biopsy. A partial sequestrectomy was performed and a six-month course of amoxycillin-clavulanate was prescribed. The dog was pain-free and showed partial resolution of the radiographic signs four months after the discontinuation of antibiotics.

Sterile nodular dermatitis in dogs

The types of canine sterile nodular dermatitis discussed in this article have in common the clinical presentation of nodules or plaques; however, they differ in many aspects such as breed predilection, distribution and evolution of cutaneous lesions, systemic involvement, response to therapy, and prognosis. The definitive diagnosis should be based on multiple skin biopsy results. Other ancillary tests may be indicated in cases of systemic involvement. In addition, serum alpha1 antitrypsin can be measured to demonstrate the association between nodular panniculitis and serum alpha1 antitrypsin deficiency. A better understanding of the etiopathogenesis of each of these interesting skin conditions necessitates extensive and systematic diagnostic approaches.

Cutaneous vasculitis and vasculopathy

Although uncommon to rare in occurrence, cutaneous vasculitides and vasculopathies are becoming better recognized entities in veterinary medicine. The heterogeneity in their clinical presentations can be confusing, and the diagnostic evaluation of suspected cases can be clinically and financially challenging. The most important step is confirming a vasculitic/vasculopathic process histologically and then searching for an underlying cause. As many cases are diagnosed as idiopathic by exclusion, a familiarity with treatment options is important and may be guided in some cases by the histological inflammatory pattern. Because of the frequent temporal association with drug administration, any case of vasculitis requires a thorough drug history and physical examination for systemic complications. Familiarity with breed-associated vasculopathies is also key in properly diagnosing and managing these problems.

Vertebrectomy, bone allograft fusion, and antitumor vaccination for the treatment of vertebral fibrosarcoma in a dog

OBJECTIVE

To describe the surgical technique of vertebrectomy with bone allograft fusion and the use of antitumor vaccine for the treatment of a primary vertebral neoplasm in a dog.

STUDY DESIGN

Case Report.

ANIMALS OR SAMPLE POPULATION

A 3 year old 32 kg female spayed mixed breed dog with progressive paraplegia.

METHODS

Myelography was performed to identify an L5 lytic lesion with spinal cord compression. A dorsal laminectomy was performed to decompress the spinal cord and obtain biopsies. Pathologic fracture of the vertebral body two days later was treated with L5 vertebrectomy, cortical allograft implantation, and bilateral plating from L4 to L6. Tumor samples were used to create an autologous cytokine-gene-engineered tumor cell vaccine. Recheck radiographs and neurologic examinations were obtained 1, 2, 7, and 13 months after surgery.

RESULTS

The histopathologic diagnosis was fibrosarcoma. Although slight osteopenia of the allograft was noted thirteen months after surgery, the allograft and plate fixation remained stable. The patient tolerated the antitumor vaccination protocol well. Two years after the procedures the dog was able to ambulate normally but remained urinary and fecal incontinent.

CONCLUSIONS AND CLINICAL RELEVANCE

Vertebrectomy and cortical allograft implantation with plating permitted this patient to return to a functional lifestyle with its owners.

Smoke exposure in dogs: 27 cases (1988-1997)

OBJECTIVE

To evaluate clinical findings, prognostic variables, and clinical course of dogs exposed to smoke.

DESIGN

Retrospective study.

ANIMALS

27 dogs exposed to smoke in residential fires.

PROCEDURE

Medical records were reviewed for 1988-1997. Time of year, signalment, interval from fire to arrival at veterinary hospital, duration of smoke exposure, clinical signs at the fire scene, physical examination findings, changes in respiratory tract signs, radiographic findings, hematologic and arterial blood gas analyses, initial treatment, clinical course, and outcome were recorded.

RESULTS

27 dogs (16 uncomplicated and 11 complicated cases) were identified. In the complicated group, 4 dogs died, 4 were euthanatized, and 3 had a complicated clinical course. Stupor or coma (8 of 17 dogs), coughing or gagging (6), and respiratory difficulty (6) were commonly observed at the fire scene. Substantial improvement was evident within 5 to 30 minutes after dogs were given supplemental oxygen at the fire scene. More severely affected dogs had a higher median PCV (58%) than less severely affected dogs (50%). Most common thoracic radiographic findings were an alveolar (10 dogs) or an interstitial (3) pattern.

CONCLUSIONS AND CLINICAL RELEVANCE

Dogs exposed to smoke can develop respiratory or neurologic complications. Monitoring progression of respiratory problems on the day after the fire may provide clinicians with clues about the severity of each dog's condition.

Insect and arachnid hypersensitivity

Insect hypersensitivity reactions can have a large number of clinical presentations. The majority of reactions are pruritic and involve the short- or sparsely haired areas of the body. Most are associated with eosinophilic infiltration into the skin, often in a perivascular pattern. The diagnosis may be based on compatible clinical signs and improvement with aggressive insect control and, in some cases, confirmation via provocative exposure. Intradermal, prick, or serum testing for allergen-specific IgE can be used to document the presence of reaginic antibodies against insect allergens. Treatments include avoidance, aggressive insect control, and symptomatic support; in some cases, immunotherapy may be useful in decreasing the severity of clinical reactions to insects.

Persistent expression of canine factor IX in hemophilia B canines

We previously demonstrated that direct intramuscular injection of recombinant adeno-associated virus (rAAV) carrying the human FIX (hFIX) cDNA can safely be administered to hemophilic B canines and express human factor IX protein; however, the functional activity of the hFIX protein could not be assessed due to anti-human FIX antibody (inhibitor) formation. To test the therapeutic efficacy of rAAV in hemophilic dogs, rAAV type 2 (rAAV2) carrying canine FIX (cFIX) cDNA was injected into the skeletal muscle of two dogs at doses of 1012-13particles. Circulating cFIX protein levels were maintained for 1 year at levels of 1-2% of normal. Hemostatic correction (WBCT and APTT) paralleled plasma FIX antigen levels. Both dogs still required plasma infusion for spontaneous and traumatic bleeding events. Inhibitors to cFIX protein were not detected in either animal by Bethesda assay. Neutralizing antibodies directed against AAV-2 capsid were pronounced and persistent. Vector DNA and mRNA transcripts were detected only at the injected skeletal muscle tissue. Analysis of both high and low molecular weight DNA identified both replicative episomal and integrated AAV species. These results demonstrate that persistent secretion of the FIX transgene protein, necessary for successful gene therapy of hemophilia B, can be achieved using the parvovirus-based rAAV vector

Parenteral nutrition in the management of a dog with lymphocytic-plasmacytic enteritis and severe protein-losing enteropathy

Management of lymphocytic-plasmacytic enteritis in a dog with whipworm infestation, hypoproteinemia, and ascites is described. Short-term parenteral nutrition hastened normalization of serum proteins, resolution of diarrhea, and weight gain. A description of the potential benefits, limitations, and possible complications of parenteral nutrition in refractory inflammatory bowel disease is given.

Large granular lymphocytic leukemia in a mixed breed dog

A mixed breed dog was diagnosed with large granular lymphocytic leukemia. Immunophenotypic analysis indicated the lymphocytes were CD3+, CD8+ T cells expressing the alpha beta T cell receptor and a leukointegrin, alpha d. Chemotherapy and splenectomy resulted in an initial reduction in the lymphocyte count.

Pericardial effusion and cardiac tamponade secondary to brodifacoum toxicosis in a dog

Hemorrhage resulting from ingestion of anticoagulant rodenticides may be evident at any traumatized site or in any body cavity. It is important for clinicians to include coagulopathies among the differential diagnoses for pericardial effusion and to evaluate clotting function before routine pericardiocentesis is performed.

Treatment of severe orthopedic infections

Severe infections are uncommon following orthopedic surgery, yet they can be frustrating for the veterinarian and owner to treat and can result in devastating consequences for the patient. This article reviews the common causes for postoperative infection, reviews established treatment, and introduces newer methods for treatment and control. A thorough understanding of the pathogenesis, application of appropriate diagnostic procedures, the institution of aggressive treatment regimens, with adherence to established principles, will often result in satisfactory outcomes even with severe orthopedic infections. For those more refractory to treatment, the use of newer treatment methods, specifically locally implantable materials for sustained release of antimicrobials can improve success in the treatment of these more difficult cases.

Eosinophilic dermatitis with edema in nine dogs, compared with eosinophilic cellulitis in humans

A unique eosinophilic dermatitis with edema in dogs is characterized by extremely erythematous coalescing macules and plaques with associated edema, and is similar to eosinophilic cellulitis (Wells' syndrome) in humans. Histopathologic features include a profound eosinophilic dermal infiltrate, focal areas of collagen fiber degeneration surrounded by eosinophils (flame figures), dilated vessels, and dermal edema. Etiopathogenesis is unknown, but a hypersensitivity reaction to medications, arthropod bites, or other foreign antigens is suspected.

The efficacy of mechanical abrasion and talc slurry as methods of pleurodesis in normal dogs

OBJECTIVE

To determine the efficacy of mechanical abrasion and talc slurry as methods for pleurodesis in normal dogs.

STUDY DESIGN

Experimental study.

ANIMALS OR SAMPLE POPULATION

Ten normal beagle dogs.

METHODS

Group I dogs had mechanical abrasion (MA) of the pulmonary and costal pleurae performed in one hemithorax with a dry gauze sponge with a median sternotomy approach. Group II dogs had 100 mL of a 1 g talc slurry (TS) administered into one hemithorax through a tube thoracostomy. Administration of the TS was visualized by using video thoracoscopy. All dogs were evaluated at 2, 10, 20, and 30 days postoperatively by means of thoracic radiography and ultrasonographic thoracic wall measurement. The dogs were euthanatized 30 days postoperatively and a gross necropsy was performed. Hemithoraces were assigned a pleurodesis score (0-4) and an obliteration grade (0-6). Tissues were collected for histopathologic examination of pulmonary pleura, costal pleura, and pleural adhesions. Pulmonary and costal pleurae were graded for the degree of fibrosis (0-4).

RESULTS

Obliteration grade and costal pleural fibrosis score were significantly higher for the treated sides in the MA dogs compared with the TS dogs. MA Dogs: Mechanical abrasion dogs had pleurodesis, obliteration, and pleural fibrosis scores that were greater on the treated side than the untreated side, however, the differences were not statistically significant. Only two MA dogs had firm adhesion of the pulmonary pleura to the costal pleura in portions of the cranial and middle lung lobes in the treated hemithorax. Thoracic wall surface area covered with adhesions was 15% and 21% in each of these two dogs. The median pulmonary pleural fibrosis score of all MA dogs for the treated hemithorax was 3 compared to 0 on the untreated side. TS Dogs: There was no statistical difference for pleurodesis scores and obliteration grades between the treated and untreated sides. No dogs showed evidence of pulmonary to costal pleural adhesions. Histopathology showed talc crossover into the untreated side in all five dogs. Median pulmonary fibrosis score of the treated hemithorax was 1 compared with 0 on the untreated side.

CONCLUSIONS

Neither method of pleurodesis produced sufficient pleural adhesions to obliterate the pleural space. It is possible that the degree of pulmonary pleural fibrosis present in MA dogs may be sufficient to limit air leakage from pulmonary blebs and bullae resulting in successful treatment of spontaneous pneumothorax.

Current concepts in the diagnosis and treatment of brain tumours in dogs and cats

Intracranial tumours occur relatively frequently in dogs, and less commonly in cats. With the availability of computed tomography (CT) and magnetic resonance imaging, more accurate determination of the location and extent of brain tumours in companion animals has become possible. Following these advances in imaging, precise CT-guided stereotactic techniques for both tumour biopsy and intratumoral drug delivery have been developed for use in cats and dogs. Also, tumour identification methods, such as crush preparation examination, have facilitated rapid tumour identification. The use of improved diagnostic techniques has resulted in an increasing demand for effective therapies for brain tumours. While surgical removal and irradiation remain important treatment considerations in the management of brain tumours of cats and dogs, the development of gene therapy strategies for treatment of intracranial tumours offers much promise, although research in this area is still at an early stage.

Use of whole body hyperthermia as a method to heat inaccessible tumours uniformly: a phase III trial in canine brain masses

In this study, whole body hyperthermia (WBH) was assessed as a means of heating intracranial tumours uniformly. Twenty-five dogs received radiation therapy and 20 the combination of radiation and WBH. Total radiation dose was randomly assigned and was either 44, 48, 52, 56 or 60 Gy. Because of WBH toxicity, intercurrent disease or tumour progression, seven of the 45 dogs received less than the prescribed radiation dose. For WBH, the target rectal temperature was 42 degrees C for 2h and three treatments were planned. In five of the 20 dogs randomized to receive WBH, only one WBH treatment was given because of toxicity. WBH toxicity was severe in six dogs, and resulted in death or interruption in treatment. Most tumours did not undergo a complete response, making it impossible to differentiate tumour recurrence from brain necrosis as a cause of progressive neuropathy. Therefore, survival was the major study endpoint. There was no survival difference between groups. One-year survival probability (95% CI) for dogs receiving radiation therapy alone was 0.44 (0.25, 0.63) versus 0.40 (0.19, 0.63) for dogs receiving radiation and WBH. There was no difference in the incidence of brain necrosis in the two treatment groups. Results suggest that use of WBH alone to increase the temperature of intracranial tumours as a means to improve radiation therapy outcome is not a successful strategy.

Balloon dilation of right ventricular outflow tract in a dog with tetralogy of Fallot

Balloon dilation was performed on a dog with tetralogy of Fallot. Immediately following balloon dilation, the peak systolic pressure gradient across the pulmonic valve declined from 97 to 63 mmHg. Doppler echocardiography following balloon dilation revealed increased pulmonary blood flow. Clinical symptoms obviously improved and the dog's improved condition was maintained for 4 months. There were no serious complications in performing the procedure. It was concluded that balloon dilation was a safe and effective treatment for a dog case with tetralogy of Fallot. Long-term follow-up studies will be required to identify the exact indications of balloon dilation for tetralogy of Fallot.