Pyogranulomatous meningoencephalitis due to Actinomyces sp. in a dog

Actinomyces sp. are commensal, filamentous, gram-positive, acid-fast-negative bacteria that can cause pyogranulomatous inflammation in animals and humans. Central nervous system (CNS) disease is a rare presentation of actinomycosis and is usually due to extension from infected wounds or seeding from distant sites. A dog with progressive, poorly localized neurologic signs had primary CNS actinomycosis without history or evidence of previous trauma or other organ involvement. Histologically, there was a severe pyogranulomatous meningoencephalitis with intralesional filamentous bacteria that were also visible on cytology of the cerebral spinal fluid (CSF) postmortem. Actinomyces sp. was cultured postmortem from the CSF, confirming the diagnosis. This case demonstrates that Actinomyces sp. can be a causative agent of primary CNS disease in dogs.     

Cutaneous actinomycosis and nocardiosis in dogs: 48 cases (1980-1990).

Medical records of 48 dogs with cutaneous actinomycosis or nocardiosis were reviewed. Male, large-breed dogs kept outdoors were overrepresented. The mean age at admission was 3.6 years. Cutaneous swelling (68%), abscesses (65%), draining tracts (48%), fever (36%), and signs of pain (13%) were the most common clinical findings. The cervicofacial area was affected in 48% of the dogs. Abdominal and thoracic wall involvement was less common. Leukocytosis, neutrophilia with left shift, monocytosis, and hyperglobulinemia were common. The diagnosis was confirmed by cytologic examination, bacteriologic culture, or histologic examination. Gram-positive filamentous bacteria were seen in 69% of the fine needle aspirates and in 50% of the biopsy specimens. Actinomyces spp were isolated from cutaneous lesions in 27 (60%) dogs. Nocardia asteroides was isolated from 1 dog. Treatment consisted of surgical debridement, drainage, and administration of antibiotics in 29 dogs (group A) and antibiotics alone in 13 dogs (group B). The infection redeveloped in 10 (42%) group-A dogs and 6 (60%) group-B dogs. Of the 10 group-A dogs with recurrent infection, 6 had resolution after a second surgery and 4 were euthanatized. Of the 6 group-B dogs, 1 had resolution after surgery, 4 were euthanatized or died because of persistent disease, and 1 had an unresolved infection. The combination of surgery and antibiotic treatment appeared to be superior to antibiotic treatment alone in resolving cutaneous Actinomyces and Nocardia infections.     

Surgical excision of ectopic thyroid carcinoma involving the base of the tongue in dogs: three cases (1980-1987)

Localized thyroid carcinoma involving the base of the tongue was diagnosed in 3 dogs examined because of a midline cervical mass rostroventral to the larynx. These masses had been present for 4 to 12 months and were firm, nonsensitive, and fixed in position. One dog had progressive dysphagia and dyspnea. Masses were surgically excised together with the base of the tongue and portions of the hyoid apparatus. Severe dyspnea that developed immediately after surgery in 1 dog was managed by tracheostomy intubation for 4 days. Transient dysphagia developed in all dogs. Hydration was maintained by IV fluid administration until water and food of gruel consistency could be swallowed 1 to 6 days after surgery. Consistency of food was gradually thickened to normal, as swallowing improved 6 days to 2 months after surgery. One dog developed aspiration pneumonia that resolved after antimicrobial administration and improved swallowing that prevented further aspiration. After 9 months, 3 years, and 6 years, the dogs were clinically normal.     

RADIOGRAPHIC FINDINGS IN TEN DOGS WITH THORACIC ACTINOMYCOSIS

The radiographic findings in ten dogs with thoracic actinomycosis are presented. Radiographic findins varied, but pleural effusion, pulmonary infiltrates and mediastinal masses were most commonly found. Rib involvement, commonly accompanying actinomycosis in man, was present in only one dog. The differential diagnosis of actinomycosis includes many disease entities, but based on the radiographic signs it may be possible to narrow down the number of possiblities considerably. A combination of mediastinal or pulmonary masses, pleural effusion and encapsulated fluid is strongly indicative for actinomycosis. For confirmation a bacteriological examination is indicated.     

Clinical evaluation of methoximorpholino-doxorubicin (FCE 23762) in dogs with spontaneous malignancies

We conducted a clinical evaluation of FCE 23762, a methoxymorpholino analog of doxorubicin, in 48 dogs with metastatic, nonresectable, or chemotherapy-resistant spontaneous malignancies at an initial dosage of 50-60 microg/kg IV every 3 weeks. Clinical evidence of toxicity was minimal; 6 dogs developed grades I, II, and III hematologic toxicities after the 1st treatment, and 1 dog developed grade II gastrointestinal toxicity. One dog became pancytopenic 4 months after discontinuation of FCE 23762. No other adverse effects were noted. Partial or complete remissions were observed in 32% of the dogs. Responses were observed both in previously untreated dogs and in those that had received prior chemotherapy, including doxorubicin. FCE 23762 is a promising new antineoplastic agent that can be used safely in dogs with cancer; doses higher than those used in this study may be used eventually in practice.     

Uterine Leiomyoma in a Spayed Poodle Bitch: A Case Report

A 16‐year‐old, spayed, female poodle dog was presented for evaluation of tenesmus, with the ability to attract male dogs and a willingness to mate. The dog had undergone an ovariohysterectomy when it was 7 years old. Haematological and serum biochemistry analyses demonstrated leucocytosis and a mild uraemia. A vaginal smear was predominantly made up of superficial cells, accounting for at least 80% of the cells. Abdominal ultrasonography revealed a heterogeneous multicystic mass at the caudal abdomen and two masses with anechoic areas adjacent to the caudal pole of each kidney. A midline exploratory laparotomy identified a uterine mass and residual ovaries that were surgically excised. Histopathological examination of the mass demonstrated that it was a leiomyoma. The left ovary had a cystic structure and the right ovary had a papillary cystic adenoma. Seven months after the surgery, the owner reported that the dog was clinically normal. To the authors’ knowledge, this is the first reported case of a uterine leiomyoma after an incomplete ovariohysterectomy in the dog.     

Osteomyelitis in dogs and cats caused by anaerobic bacteria

Localised osteomyelitis was diagnosed in 2 dogs and 2 cats. The disease was caused by fight wounds in 3 cases. Radiographic examination demonstrated a circumscribed zone of cortical bone lysis, sequestra and periosteal new bone. Each case was treated surgically by sequestrectomy and debridement. Infection was due mainly to anaerobic bacteria. The pathogenic bacteria isolated from the lesions of dogs were Actinomyces viscosus, Fusobacterium nucleatum and Bacteroides spp, and from the lesions in cats were Clostridium villosum , Peptostreptococcus anaerobius, Wolinella recta and Bacteroides gingivalis. As all the bacteria were sensitive to penicillin, each case was treated with penicillin and by irrigation of the wound. This resulted in resolution of the disease, within 4 weeks, in all cases.     

Surgical excision of primary canine rectal tumors by an anal approach in twenty-three dogs

OBJECTIVE: To describe an anal approach for excision of primary rectal tumors in dogs and to report outcome. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=23) with primary rectal tumors. METHODS: Review of medical records (1990-2000) of dogs with primary rectal neoplasia excised surgically using an anal approach with rectal prolapse. With dogs anesthetized, the rectum was prolapsed, stabilized with stay sutures during tumor excision with 1 cm margins to the level of the muscularis, then the rectal mucosa was sutured. RESULTS: Each dog had only 1 tumor type (adenocarcinoma [8], solitary polyp [5], carcinoma [4], plasmacytoma [2], adenoma [1], leiomyoma [1], mucinous carcinoma [1], and papilloma [1]). Mean tumor volume was 3.1 cm(3) (range 0.1-37.7 cm(3)). Postoperative complications (rectal bleeding [5], tenesmus [4]) were mild and resolved within 7 days after surgery; another dog had partial mucosal dehiscence identified at 6 days. The primary tumor was incompletely excised in 1 dog (4.3%), and local recurrence occurred 16 and 24 months after surgery in 2 dogs. Outcome beyond the immediate postoperative period was known for 18 dogs, including 2 dogs still alive. Mean postoperative disease-free interval for these 18 dogs was 36.8 months (range 5-84 months). CONCLUSION: Surgical excision of tumors of the caudal rectum can be accomplished through the anus after rectal prolapse. CLINICAL RELEVANCE: An anal approach facilitated by rectal prolapse should be considered as a viable option for the surgical treatment of selected cases of tumors of the caudal aspect of the rectum in dogs.     

RADIATION PNEUMONITIS IN THREE DOGS

Radiation pneumonitis developed within the radiation treatment field in three dogs with soft tissue sarcomas located on or adjacent to the thoracic wall. Radiographic signs compatible with a diagnosis of radiation pneumonitis developed from one (n = 2 dogs) to two (n = 1 dog) months after completion of therapy. The initial radiographic sign was an alveolar infiltrate in all three dogs. At subsequent examinations at variable time periods after treatment, radiographic findings included: bronchiectasis (n = 3 dogs), alveolar infiltrate (n = 2 dogs), decreased lung volume (n = 2 dogs), and unstructured interstitial opacification (n = 1 dog). Necropsy examination of one dog at fourteen months after the completion of radiotherapy showed evidence of pulmonary fibrosis within the irradiated lung. Necropsy examination of the second dog did not show any evidence of radiation induced changes. It is possible that histopathologic examination did not include irradiated lung. No clinical signs that could be attributed to the radiation pneumonitis were observed in any dog. It appears that approximately 25% of the lung can be safely irradiated to high doses, if indicated, in order to deliver an adequate dose of radiation to a primary tumor site.     

Spirocerca lupi esophageal granulomas in 7 dogs: resolution after treatment with doramectin

Seven dogs with Spirocerca lupi esophageal granulomas were identified based on the site of involvement (ie, distal esophagus) and characteristic endoscopic appearance. Six dogs presented with signs of esophageal disease and 1 dog was asymptomatic. Ova were only identified in the feces of 2 dogs. On thoracic radiographs, 4 dogs had evidence of a caudodorsal mediastinal mass, and 2 of these dogs had spondylitis of midthoracic vertebrae. On endoscopy, single esophageal nodules were observed in 5 dogs, 1 dog had 3 nodules, and 1 dog had 6 nodules. All 7 dogs were treated with doramectin at a dosage of 200 microg/kg SC at 14-day intervals for 3 treatments. Dogs had physical and endoscopic examinations at 2, 4, and 6 weeks after treatment. By 6 weeks, clinical signs had resolved in 6 dogs (1 dog was asymptomatic), and the esophageal nodules had completely resolved in 4 dogs, and incompletely resolved in 3 dogs. Two dogs with incomplete resolution were treated again with doramectin at 500 microg/kg PO daily for an additional 6 weeks. Complete resolution of the esophageal nodules was confirmed by endoscopy in all dogs. Nodules had resolved in 4 dogs by 6 weeks, in 2 dogs by 12 weeks (after 6 weeks additional daily oral therapy), and in 1 dog 22 months after the initial 200 microg/kg treatment regimen. No dog experienced adverse effects to the drug, and all symptomatic dogs have been free of disease for periods ranging from 3 to 4 years.     

Phase II, open-label trial of single-agent CCNU in dogs with previously untreated histiocytic sarcoma

Background: Histiocytic sarcoma (HS) is an aggressive neoplasm in dogs, and in most instances, the disease is localized, but not amenable to surgical removal, or is disseminated. Affected patients usually die within 6 months. There have been no prospective studies to determine efficacy of single‐agent chemotherapy in dogs with HS. Hypothesis: Single‐agent CCNU [1‐(2‐chloroethyl)3‐cyclohexyl‐1‐nitrosourea; lomustine] has antitumor activity against HS in dogs. Animals: Twenty‐one dogs with histologically confirmed, nonresectable localized or disseminated HS. Methods: Prospective, open‐label phase II clinical trial in which dogs with previously untreated HS were uniformly treated with CCNU as a single oral dosage of 90 mg/m² every 4 weeks. The primary outcome measure was reduction in tumor size. Results: Fourteen dogs with disseminated HS and 7 with localized HS were enrolled between 1999 and 2008. Overall response rate was 29% (95% confidence interval [CI], 14–50%) for a median of 96 days (95% CI, 55–137 days). Three dogs (1 disseminated, 2 localized) had complete responses lasting for 54–269 days and 3 dogs (2 disseminated, 1 localized) had partial responses lasting for 78–112 days. Conclusions and Clinical Importance: CCNU, when used as a single agent, has activity against HS in dogs. Evaluation of CCNU postoperatively for dogs with resectable localized HS and as part of combination therapy for tumors that are nonresectable or disseminated should be considered.     

Bilateral conjunctival masses in two dogs

Bilateral conjunctival masses in 2 dogs were excised. In one dog, the masses represented hemangiomas that may have been related to exposure to UV radiation. In the other dog, they represented conjunctival inclusion cysts of probable congenital origin.     

Sodium iodide I 131 treatment of dogs with nonresectable thyroid tumors: 39 cases (1990-2003)

OBJECTIVE: To determine outcome for dogs with nonresectable thyroid carcinomas treated with sodium iodide I 131 and identify factors associated with outcome. DESIGN: Retrospective case series. Animals-39 dogs. PROCEDURES: A definitive or presumptive diagnosis of thyroid tumor was made on the basis of cytologic or histologic examination, abnormal accumulation of sodium pertechnetate Tc 99m during scintigraphy, or both, and dogs were treated with sodium iodide I 131. Dogs with cervical thyroid tumors were evaluated 3 to 6 weeks after 131I therapy, and residual tumor was resected when feasible. RESULTS: Prior to 131I therapy, 32 dogs had a solitary mass and 7 had metastases; 21 were hyperthyroid, 16 were euthyroid, and 2 were hypothyroid. Median survival time for dogs with local or regional tumors (ie, stage II or III) was significantly longer (839 days) than median survival time for dogs with metastasis (366 days). Tumor site (cervical vs ectopic), dose of sodium iodide I 131, age, body weight, treatment (131I therapy alone vs 131I therapy followed by surgery), and serum T4 concentration prior to 131I therapy were not significantly associated with survival time. Three dogs died of radioiodine-associated myelosuppression within 3 months after treatment, but no specific factor associated with development of toxicosis was identified. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that 131I therapy may result in prolonged survival times in dogs with nonresectable thyroid tumors, regardless of serum thyroxine concentration prior to treatment. Dogs undergoing 131I therapy should be monitored for signs of bone marrow suppression.     

Pythiosis of the digestive tract in dogs from Oklahoma

Enteric pythiosis was diagnosed in nine dogs in Oklahoma. Eight dogs had anorexia and weight loss. Two of these dogs had diarrhea; two dogs exhibited vomiting and diarrhea; and one dog had vomiting. One dog presented with dysphagia. Seven dogs had either a palpable or radiographically visible abdominal mass. These seven dogs had localized regions of mucosal ulceration and thickened gastric or intestinal walls with some involvement of the adjacent mesentery or omentum. Two dogs had enlarged regional mesenteric lymph nodes. One dog that presented with dysphagia had an oropharyngeal mass involving the larynx and cranial esophagus. Microscopically, there was transmural chronic sclerosing and granulomatous to pyogranulomatous inflammation with arteritis. Pythium spp. were identified in all specimens by immunohistochemistry.     

TREATMENT OF DIFFERENTIATED THYROID CARCINOMA IN 7 DOGS UTILIZING 131I

Seven dogs with thyroid gland carcinoma were treated with ¹³¹I and hormone suppressive therapy either alone (3 dogs) or in combination with surgery (3 dogs) or ¹³⁷Cs teletherapy and chemotherapy (1 dog). Empirically chosen doses of 75 to 137 mCi of ¹³¹I were given orally (2 dogs) and intravenously (5 dogs). Adverse effects were limited to acute, transient bone marrow hypoplasia and pancytopenia. Nominal objective reduction in tumor volume or size and number of pulmonary metastases was observed in 4 dogs treated with ¹³¹I and thyroxine. Of these 4 dogs, 2 had stable disease for periods of 4 and 12 months while a third dog had stable disease for 27 months following two ¹³¹I treatments at 3 month intervals. The fourth dog had progressive disease. Two dogs with mediastinal metastases showed reduction in localization of ^99mTc pertechnetate and radioiodine following 2 and 3 treatments using ¹³¹I. It appears that relatively high doses of ¹³¹I can be used safely for the treatment of canine thyroid tumors and that further investigation can be justified to define its efficacy.     

Vinblastine and prednisolone as adjunctive therapy for canine cutaneous mast cell tumors

Twenty-seven dogs with inadequately excised, cutaneous mast cell tumors (MCT; 20 residual microscopic disease, seven marginal excision) were treated with a vinblastine and prednisolone chemotherapeutic protocol. Twenty dogs were available for follow-up examination after 12 months. One dog suffered local recurrence of the tumor, four dogs developed new cutaneous tumors, and one dog had both events. Fourteen dogs were free of MCT. There was no confirmed tumor-related mortality. Although toxicity from the chemotherapy was generally mild, one dog died of sepsis during treatment.     

Treatment of unresectable hepatocellular adenoma in dogs with transarterial iodized oil and chemotherapy with and without an embolic agent: A report of two cases

Transarterial iodized oil with chemotherapy was evaluated in two dogs with large, surgically unresectable hepatocellular adenoma. A single cycle of therapy was used in each dog. Chemoembolic mixtures varied: doxorubicin emulsified with iodized oil radiographic contrast (case 1), doxorubicin and mitomycin C emulsified with iodized oil radiographic contrast (case 2). In addition, dog 2 underwent arterial embolization with polyvinyl alcohol granules. Response was assessed by computed tomography at 1 and 3 months after treatment. Superselective catheterization of the hepatic arterial branch supplying the tumour was not achieved in either case. In the immediate post‐operative period, both dogs developed mild clinical signs that may have been consistent with post‐embolization syndrome, but neutropenia and reduced liver function were not observed. Tumour response was minimal: stable disease at 1 month and progressive disease at 3 months was observed in both cases.     

Transarterial ductal occlusion with the Amplatzer vascular plug in 31 dogs

Background: Transarterial ductal occlusion with the Amplatzer vascular plug was first reported in dogs by Hogan et al in 2005. Hypothesis: Use of the Amplatzer vascular plug is a safe, efficacious method of patent ductus arteriosus (PDA) occlusion. Animals: Thirty‐one client‐owned dogs with PDA. Methods: Records of 31 dogs in which transarterial occlusion of PDA with an Amplatzer vascular plug was attempted were reviewed. Results: All dogs had a type II PDA, with 27 dogs having type IIA morphology and 4 dogs having type IIB morphology. Appropriate device deployment was achieved in 29 of 31 dogs. Postdeployment angiography in 21 dogs documented complete occlusion in 10 dogs, trivial residual flow in 5 dogs, mild residual flow in 2 dogs, moderate residual flow in 3 dogs, and severe residual flow in 1 dog. Transthoracic color Doppler echocardiography documented complete occlusion in 22 dogs, whereas 2 dogs had trivial residual flow, 2 dogs had mild residual flow, 2 dogs had mild to moderate residual flow, and 1 dog had severe residual flow. Of the 7 dogs with residual flow, 2 had complete occlusion 2–4 months postoperatively, 1 had moderate residual flow 1 month postoperatively, and 4 were lost to follow‐up. One dog required a larger device than was able to be deployed through the largest sheath placed in the femoral artery. Pulmonary embolization of the device occurred in 1 dog. Conclusion: We conclude that ductal occlusion with an Amplatzer vascular plug is a safe and efficacious therapy for PDA in dogs.     

PULMONARY ACTINOMYCOSIS IN A DOG

A six-year-old spayed female mixed-breed dog was evaluated for coughing, dyspnea, exercise intolerance, and intermittent fever of four month's duration. Extensive alveolar, interstitial, and peribroncial infiltration was observed throughout the lung fields, Pulmonary actinomycosis was diagnosed by isolation of Actinomyces from anaerobic cuture of a transtracheal aspirate. Therapy for Actinomycs resulted in clinical remission; however, radiographic evidence of a severe pulmonary pathologic condition remained 45 days after the initiation of therapy. The dog was asymptomatic for pulmonary disease two years following treatment.     

Microneurovascular Free Digital Pad Transfer in the Dog

By cadaver dissections, the fifth digit of the canine hind limb was determined to have a consistent neurovascular anatomy, and therefore be a suitable donor for an axial pattern digital pad flap. The defined digital pad flap was transferred to the region of an excised metacarpal pad by microneurovascular anastomoses in five operations on four dogs. One flap failure was considered to result from failure of the venous anastomosis. In all four successful transfers, cutaneous sensation was reestablished on average in 78 days. There was histologic evidence of nerve regeneration across the anastomosis in one dog at week 24. The transferred pads of three dogs monitored for 15 months underwent hypertrophic changes. There were no complications in two active dogs. In one dog, superficial ulceration of a region of the flap adjacent to the pad required surgical revision. This dog continued to show mild lameness after daily runs of 3 to 4 km.