Detection of Bartonella henselae DNA in two dogs with pyogranulomatous lymphadenitis

CASE DESCRIPTION: 1 dog evaluated because of inappetence and lameness of the left hind limb of 1 day's duration and 1 dog evaluated because of inappetence, fever, and lymphadenopathy of 2 weeks' duration. CLINICAL FINDINGS: Histologic examination of excisional biopsy specimens from lymph nodes revealed pyogranulomatous lymphadenitis in both dogs. Quantitative real-time PCR assays detected Bartonella henselae DNA in blood samples and affected lymph node specimens from both dogs. Antibodies against B. henselae were not detected via immunofluorescent antibody testing during active disease in either dog. TREATMENT AND OUTCOME: 1 dog recovered after 6 weeks of treatment with doxycycline (5 mg/kg [2.3 mg/lb], p.o., q 12 h), whereas the other dog recovered after receiving a combination of azithromycin (14.5 mg/kg [6.6 mg/lb], p.o., q 24 h for 21 days), doxycycline (17.3 mg/kg [7.9 mg/lb], p.o., q 24 h for 4 weeks), and immunosuppressive corticosteroid (prednisone [3 mg/kg {1.4 mg/lb}, p.o., q 24 h], tapered by decreasing the daily dose by 25% every 2 weeks) treatment. CLINICAL RELEVANCE: B. henselae is implicated as a possible cause or a cofactor in the development of pyogranulomatous lymphadenitis in dogs. In dogs with pyogranulomatous lymphadenitis, immunofluorescent assays may not detect antibodies against B. henselae. Molecular testing, including PCR assay of affected tissues, may provide an alternative diagnostic method for detection of B. henselae DNA in pyogranulomatous lymph nodes.     

Pure white cell aplasia in a dog

A 3-year-old Irish Wolfhound was evaluated because of acute onset of lethargy and fever. Severe neutropenia (0/microL; reference interval 2500-11,200/microL) was associated with granulocyte aplasia in the bone marrow (myeloid:erythroid ratio, 0.009:1). Antineutrophil antibodies were assessed by an indirect immunofluorescence assay using flow cytometry. When normal canine leukocytes were incubated with the patient's serum and anti-IgG, a marked shift was observed in the forward-angle light scatter of the neutrophil population, and the monocyte cluster disappeared, possibly the result of fragmentation or lysis. Both neutrophil fluorescence intensity (309 +/- 11 median channel units [MCU], control values 107-152 MCU) and the percentage of neutrophils with increased fluorescence intensity (61 +/- 5%, control values 3.8-13.7%) were increased in the patient's serum, consistent with the presence of antineutrophil antibodies. Repeated episodes of neutropenia occurred while treatment with steroidal and nonsteroidal immunosuppressive therapy was initiated and modified. The neutrophil count eventually stabilized in the low-normal range, and the dog was maintained for the next 15 months on prednisone (0.4 mg/kg PO q 48 h) and azathioprine (2 mg/kg daily). During this period, the dog developed immune-mediated hemolytic anemia and thrombocytopenia, decubital ulcers, nasal aspergillosis, and eventually, multi-organ septicemia, which led to euthanasia on day 784. A diagnosis of pure white cell aplasia was made in this dog, based on the many similarities to human patients with pure white cell aplasia, including severe neutropenia with selective granulocyte aplasia, serum antineutrophil antibodies, remission dependent on treatment with immunosuppressive therapy, and recurrent bacterial infections.     

Cutaneous lesion caused by Mycobacterium tuberculosis in a dog

A 5-month-old female mixed-breed dog was examined because of nonhealing wounds in the right submandibular region. Treatment with antibiotics and surgical excision was ineffective. Specimens of the right mandibular lymph node and surrounding tissues were submitted for bacteriologic culturing, and Mycobacterium tuberculosis was isolated. The dog was euthanatized. The risk of infection of human beings who associate with dogs that have cutaneous wounds caused by mycobacteria is unknown.     

Intra-abdominal botryomycosis in a dog

A 6-year-old 41.8-kg (92-lb) sexually intact male German Shepherd Dog used as an attack and pursuit dog by the local police department was examined because of general malaise and sudden onset of ataxia. Abnormal findings included a high WBC count, fever, and ongoing weight loss. Physical examination was unrevealing initially, in part because of the aggressive nature of the dog. Following treatment with antibiotics, an abdominal mass was detected during a second physical examination, and was confirmed radiographically. Subsequent ultrasound examination revealed a walled mass of mixed echogenicity, with areas of detectable fluid movement. A laparotomy was performed to remove the mass, which weighed 2.2 kg (4.5 lb). Histologic findings were consistent with botryomycosis, and Staphylococcus intermedius was isolated on bacteriologic culture. Postoperative treatment consisted of intravenous, intra-abdominal, and oral administration of antibiotics. Diagnosis of botryomycosis requires histologic examination and bacteriologic culture of the lesion. Treatment consists of surgical intervention and administration of antimicrobials. Botryomycosis is a poorly understood and rarely reported disease found in many species. A computer search of the literature failed to reveal any previous reports of intra-abdominal botryomycosis in dogs.     

Multisystemic infection with an Acanthamoeba sp in a dog

CASE DESCRIPTION-A 10-month-old Boxer was evaluated for fever and signs of cervical pain. CLINICAL FINDINGS-Physical examination revealed lethargy, fever, and mucopurulent ocular and preputial discharge. On neurologic examination, the gait was characterized by a short stride. The dog kept its head flexed and resisted movement of the neck, consistent with cervical pain. Clinicopathologic findings included neutrophilic leukocytosis, a left shift, and monocytosis. Cervical radiographs were unremarkable. Cerebrospinal fluid analysis revealed neutrophilic pleocytosis and high total protein content. On the basis of signalment, history, and clinicopathologic data, a diagnosis of steroid-responsive meningitis-arteritis was made. TREATMENT AND OUTCOME: The dog was treated with prednisone (3.2 mg/kg [1.45 mg/lb], PO, q 24 h), for 3 weeks with limited response. Consequently, azathioprine (2 mg/kg [0.9 mg/lb], PO, q 24 h) was administered. Three weeks later, the dog was evaluated for tachypnea and lethargy. Complete blood count revealed leukopenia, neutropenia, and a left shift. Thoracic radiography revealed a diffuse bronchointerstitial pattern. The dog subsequently went into respiratory arrest and died. On histologic evaluation, amoebic organisms were observed in the lungs, kidneys, and meninges of the brain and spinal cord. A unique Acanthamoeba sp was identified by use of PCR assay. CLINICAL RELEVANCE: This dog developed systemic amoebic infection presumed to be secondary to immunosuppression. The development of secondary infection should be considered in animals undergoing immunosuppression for immune-mediated disease that develop clinical signs unrelated to the primary disease. Although uncommon, amoebic infection may develop in immunosuppressed animals. Use of a PCR assay for identification of Acanthamoeba spp may provide an antemortem diagnosis.     

Delayed recurrence of nasal aspergillosis in a dog

A two-year-old, female spayed Australian cattle dog was diagnosed with nasal aspergillosis. The dog was treated topically with clotrimazole. Clinical signs recurred two months later and the clotrimazole treatment was repeated and 5 mg/kg itraconazole twice daily was added to it. The recommended dose of itraconazole for nasal aspergillosis is 5 mg/kg twice daily administered orally. The dog's symptoms completely resolved, but it developed an adverse febrile reaction to the Itraconazole. The Itraconazole was discontinued and the dog remained asymptomatic for four years. The dog then developed mucopurulent discharge from the right nostril and was diagnosed as having recurrent nasal aspergillosis. Itraconazole at 5 mg/kg twice daily was prescribed, which again induced a fever. When the itraconazole was decreased to 5 mg/kg once daily there were no fever episodes, but the nasal discharge was not completely resolved. The dog was then treated with topical clotrimazole Infusion, and maintained on 5 mg/kg itraconazole daily. To the authors' knowledge, this case is unique because of the delayed recurrence of nasal aspergillosis. Additionally, the idiosyncratic febrile reaction to the itraconazole has not previously been reported in the veterinary literature, but is similar to reports of drug-induced fever in humans.     

Equine Granulocytic Anaplasmosis: A Case Report and Review

A 15 year-old Thoroughbred mare was examined for lethargy, fever, and inappetence of 1-day duration. A hard-bodied tick was removed from the horse. A complete blood count (CBC) demonstrated leukopenia with lymphopenia and thrombocytopenia. Morulae were visualized in circulating granulocytes. A polymerase chain reaction (PCR) confirmed the identity of these organisms as Anaplasma phagocytophilum. The horse was treated symptomatically for fever and inappetence with flunixin meglumine (1.1 mg/kg [0.5 mg/lb]) and oral electrolyte paste. Oxytetracycline (6.6 mg/kg [3 mg/lb] intravenously every 24 hours) treatment was begun as soon as a definitive diagnosis was determined. The mare responded to treatment, but she was switched to oral doxycycline (10 mg/kg [4.5 mg/lb] every 12 hours) after 5 days because of perivascular swelling at the injection site. Complete resolution of clinical signs was seen. There was no evidence of recurrence 1 year later. No additional horses at the farm were affected. The horse in this report presented for lethargy, inappetence, and fever, with limited other abnormalities. This represents a classical presentation of a mild to moderate case of anaplasmosis, which had not previously been reported in Virginia. The disease may be more widespread than has been previously reported, and it should warrant inclusion on a complete differential diagnosis list in a case of fever of unknown origin.     

Juvenile sterile granulomatous dermatitis and lymphadenitis in the dog

Juvenile sterile granulomatous dermatitis and lymphadenitis is a rare immune-mediated skin disease in young dogs. History, signalment, diagnostics, treatment, and outcome in 10 dogs are described. The age ranged from 8 - 36 weeks. The lymph nodes were enlarged in all dogs, especially the mandibular and prescapular lymph nodes. Systemic signs including fever were present in 8 dogs. Seven dogs suffered from blepharitis and painful edema of the muzzle with hemorrhagic discharge, pustules and papules. Cytology of pustules and lymph node aspirates revealed a pyogranulomatous inflammation. In 7 cases the diagnosis of juvenile sterile granulomatous dermatitis and lymphadenitis was confirmed by histology. Nine dogs were treated with prednisolone (0.5 - 1.25 mg/kg BID), H2-receptor antagonists and analgetics; all dogs were treated with antibiotics. Four dogs were treated with eye ointment containing antibiotics and glucocorticoids. The prednisolone dosage was tapered over 3 - 8 weeks. One dog had a relapse.     

Mycotic endophthalmitis in a dog caused by Candida albicans

A case of mycotic endophthalmitis in the dog caused by Candida albicans is presented. The 3-year-old dog had a history of bloody diarrhea 3 months previously. The dog presented with acute signs of unilateral panuveitis. Aqueocentesis, vitreocentesis, and routine blood tests were performed but did not contribute to the diagnosis. The posterior segment could not be visualized because of flare and fibrin. On day 7 ultrasonography showed retinal separation which progressed to vitreous compartmentalization and abscessation by day 14. Three weeks after onset, glaucoma developed and enucleation was performed. Histology revealed the yeast Candida to be the causative agent. Post-enucleation serum Candida antibody titer was 1 : 640 (human threshold 1 : 120), as determined by agglutination test. A relapse of enteric signs 3 months later led to the diagnosis of chronic lymphocytic enteritis. An hematogenous route of infection is suspected.     

Cardioversion with lidocaine of vagally associated atrial fibrillation in two dogs

Two dogs with acute onset atrial fibrillation (AF) were cardioverted to sinus rhythm by the administration of 2 mg/kg lidocaine given intravenously. Each dog was believed to have AF initiated because of elevated vagal tone. This report has potential clinical impact for a subset of dogs because it offers a treatment to circumvent persistent AF. Furthermore, this encouraging result of a pharmacologic cardioversion suggests that further investigation would be of interest to ascertain the effectiveness and mechanism of the antiarrhythmic action of lidocaine in vagally induced AF.     

Septic pleuritis and abdominal abscess formation caused by Rhodococcus equi in a foal

A 3-month-old female Arabian horse was evaluated because of fever, respiratory distress, lethargy, and decreased appetite of 5 days' duration. Pleural effusion was diagnosed on the basis of ultrasonographic and radiographic examinations. Cytologic examination of pleural fluid collected via thoracocentesis revealed septic inflammation; bacteriologic culture of a sample of that fluid yielded Rhodococcus equi. A large intra-abdominal mass adjacent to the body wall was identified ultrasonographically. A specimen of the mass was collected via aspiration; the specimen was identified cytologically as purulent exudate that contained large numbers of rod-shaped bacteria, which confirmed abdominal abscess formation. Bacteriologic culture of a sample of the exudate also yielded R. equi. The foal was treated with azithromycin (10 mg/kg [4.5 mg/lb], PO, q 24 h for 5 days then q 48 h) and rifampin (5 mg/kg [2.3 mg/lb], PO, q 12 h) for 8 weeks and metronidazole (15 mg/kg [6.8 mg/lb], PO, q 8 h) for 3 weeks. Clinically, the foal responded to antimicrobial treatment within 2 weeks. At 8 weeks after the initial evaluation, ultrasonographic examination of the foal revealed resolution of the pleural effusion and abdominal abscess. In foals, R. equi infection typically results in pyogranulomatous pneumonia, and pleural effusion is an uncommon clinical sign. The combination of azithromycin and rifampin appears to be an effective treatment for R. equi infection in foals.     

Computed tomography diagnosis of eight dogs with brain infarction

Objective Medical records of eight dogs presenting with acute onset of neurological signs and a diagnosis of brain infarction as determined by computed tomography (CT) imaging were reviewed. Design Retrospective single-centre case review Results Ischaemic infarction in the territory of the rostral cerebellar artery was identified in three spaniel-breed dogs. All cerebellar infarcts were non-haemorrhagic. Telencephalic infarcts were identified in five dogs, in the territories of the middle cerebral artery (2/5) and rostral cerebral artery (3/5). One of these dogs had an ischaemic infarction, but all other infarctions appeared haemorrhagic. All dogs were geriatric (≥8 years old), with concurrent medical conditions identified in six dogs. One dog was euthanased after diagnosis because of the severity of its neurological signs and one dog was euthanased as a result of associated renal disease 2 months after diagnosis. Six dogs were alive at least 1 year after diagnosis. Conclusions CT is useful in the diagnosis of cerebrovascular accident in dogs, which can present as a spectrum of images with early changes in attenuation and subtle mass effects detected after infarction. CT is particularly sensitive for detecting haemorrhagic infarction, but under-represent ischaemic and lacunar infarctions when compared with MRI.     

A comparative study of the pharmacokinetics of thiopental in the rabbit, sheep and dog

The central arterial pharmacokinetics of thiopental were studied in six rabbits, six sheep and six dogs after a short infusion at approximately 10 mg/kg min. Thiopental was infused to a defined electro-encephalographic endpoint (EEG burst suppression). The time to reach early burst suppression was longer in the dog (3.9 +/- 0.5 min) compared with the sheep (3.0 +/- 0.6 min) and the rabbit (2.5 +/- 0.5 min). The total dose required to produce the same level of EEG activity was higher in the dog (35.9 +/- 6.8 mg/kg) compared with the sheep (24.3 +/- 5.3 mg/kg) and the rabbit (21.6 +/- 6.8 mg/kg). The plasma concentration-time data for each animal was fitted using non-linear regression to a bi- or tri-exponential function. In all animals, the plasma-time profile was best described as a tri-exponential decay. The initial volume of distribution was similar in all three species (rabbit, 38.6 +/- 10.0 mg/kg; sheep, 44.5 +/- 9.1 ml/kg; dog, 38.1 +/- 18.4 ml/kg). The maximum arterial plasma thiopental concentration achieved at EEG burst suppression was higher in the sheep (221.8 +/- 27.9 micrograms/ml) than the dog (164.7 +/- 29.9 micrograms/ml) or the rabbit (112.3 +/- 15.1 micrograms/ml). Thiopental distribution clearance was slower in the sheep (43.6 +/- 15.1 ml/min/kg) compared with the rabbit (110.5 +/- 18.7 ml/min kg) and the dog (97.2 +/- 47.2 ml/min kg). Elimination half-life was extended in the sheep (251.9 +/- 107.8 min) and dog (182.4 +/- 57.9 min) relative to the rabbit (43.1 +/- 3.4 min).(ABSTRACT TRUNCATED AT 250 WORDS)     

Putative transmission of Mycobacterium tuberculosis infection from a human to a dog

A 3.5-year-old Yorkshire Terrier was evaluated for anorexia and vomiting; infection with Mycobacterium tuberculosis was diagnosed by use of histology, bacteriologic culture, and polymerase chain reaction (PCR) assay on various tissues. The dog was living with a human with an established M. tuberculosis infection. Findings were unique in that diagnosis of M. tuberculosis infection was obtained via PCR techniques, and isolates from the owner and dog were matched via restriction fragment length polymorphism fingerprinting. Dogs infected with M. tuberculosis from humans are most commonly infected via the respiratory tract. Clinical signs in dogs are variable and depend on the integrity of the immune system and the degree of dissemination. Diagnosis can often be obtained through histopathology and bacteriologic culture; additional diagnostic techniques are also available. Treatment of a dog with confirmed M. tuberculosis infection is controversial, and at least 6 months of multidrug treatment is required.     

Granulomatous disease associated with Bartonella infection in 2 dogs

Shortly after removal of an engorged tick from the left ear, a 4-year-old Greyhound was referred for evaluation of fever and a rapidly enlarging mass in the region of the left submandibular lymph node. Histopathologic evaluation of the lymph node resulted in a diagnosis of severe granulomatous lymphadenitis. An 11-year-old mixed-breed dog was referred for evaluation of a 6-week history of serous nasal discharge. Histologic examination of a surgical biopsy from a nasal mass indicated multifocal granulomatous inflammation with fibrosis. Serum samples obtained from both dogs were reactive by immunofluorescent assay to Bartonella vinsonii subsp. berkhoffii antigens (reciprocal titers of 128). Although Bartonella organisms were not isolated by lysis centrifugation blood culture, Bartonella DNA was amplified from tissue samples obtained from each dog (lymph node biopsy from dog 1 and nasal biopsy from dog 2) using primers that amplify a portion of the 16S rRNA gene followed by Southern blot hybridization using a genus-specific probe. Additionally, restriction fragment length polymorphism (RFLP) analysis of a Bartonella-specific citrate synthase gene product obtained from dog 2 resulted in a restriction pattern identical to B. vinsonii subsp. berkhoffii. This is the 1st report of granulomatous disease in dogs associated with Bartonella infection.     

Subcutaneous embryonal rhabdomyosarcoma in a dog: cytologic, immunocytochemical, histologic, and ultrastructural features

Abstract: A subcutaneous mass on the left antebrachium of an 11‐year‐old intact female English Pointer dog was evaluated presurgically by cytologic examination and immunocytochemical staining. The sample consisted of discrete, variably sized, markedly pleomorphic neoplastic cells that expressed vimentin with diffuse cytoplasmic staining, desmin with focal paranuclear staining, and myoglobin with diffuse cytoplasmic staining, consistent with a diagnosis of rhabdomyosarcoma. Lymphocytic and histiocytic markers were negative. Aspirates of the enlarged ipsilateral prescapular lymph node were positive for metastatic disease. Surgical excision of the tumor and lymph node were followed by histologic and electron microscopic examination. Histomorphologic appearance of neoplastic cells from the mass and the lymph node paralleled cytologic findings; the histologic diagnosis was round cell variant of embryonal rhabdomyosarcoma. By ultrastructural evaluation, cells contained numerous mitochondria and masses of cytoplasmic tangled myofilaments, features typical of rhabdomyoblasts. The dog received doxorubicin (30 mg/m²) every 3 weeks for 5 treatments. Local recurrence developed 6 months after resection but was not treated. Despite a guarded prognosis and untreated local recurrence, the dog was still alive 18 months after surgery. Cytologic evaluation and immunocytochemical staining were pivotal for the presurgical diagnosis of rhabdomyosarcoma.     

Abdominal aortic aneurysm associated with systemic fungal infection in a German shepherd dog

A 2 yr old spayed female German shepherd presented with a chief complaint of acute onset paraparesis and weight loss. At presentation, the dog was pyrexic, nonambulatory, and had generalized muscle wasting. Neurolocalization was consistent with a thoracolumbar spinal cord lesion. An abdominal ultrasound was performed and revealed a focal dilation (4 cm) of the terminal aorta with evidence of blood stasis consistent with an aortic aneurysm. The dog was euthanized shortly after admission to the hospital and a post mortem examination was performed. Fungal organisms were identified in the aortic aneurysm as well as from the thoracic vertebrae, mesenteric lymph nodes, axillary lymph nodes, spleen, kidneys, liver, lungs, and heart. Although the morphology was consistent with Candida spp., immunohistochemistry and PCR could not definitively identify the causative organism. Mycotic aortic aneurysms are a rare finding in humans and have not been previously reported in the dog. To the authors' knowledge, this is the first known report of an aortic aneurysm associated with systemic fungal infection in a dog.     

Acute necrotizing myopathy in a dog

A 9 yr old spayed female cocker spaniel presented for an acute onset of weakness. Rhabdomyolysis and myoglobinuria were found 36 hr after presentation. The dog was managed for several electrolyte and mineral abnormalities and rhabdomyolysis-induced acute renal failure. The diagnosis of idiopathic necrotizing myopathy was determined by histopathology and by the exclusion of underlying infectious agents and metabolic defects. The dog recovered completely from the acute crisis and acute renal failure.     

Peripheral polyneuropathy in a dog with functional islet B-cell tumor and widespread metastasis

A 12-year-old female Irish Setter was examined because of recurrent episodes of hindlimb weakness. The dog was not ataxic, but had generalized muscular atrophy, decreased patellar reflexes, and slow proprioception. Blood glucose content was low (32 mg/dl) and the amended insulin-glucose ratio was high (9,600). Electromyographic studies showed evidence of polyneuropathy. The diagnosis was functional islet B-cell tumor with peripheral neuropathy. Exploratory laparotomy was performed. Widespread metastases were observed and the dog was euthanatized because of the poor prognosis. The dog was necropsied and the diagnosis was confirmed on the basis of microscopic findings.     

A combination chemotherapy protocol with dose intensification and autologous bone marrow transplant (VELCAP-HDC) for canine lymphoma

Twenty-eight dogs with lymphoma were treated with a 12-week, 5-drug chemotherapy protocol concluding with high-dose cyclophosphamide supported by autologous bone marrow transplants. A dose escalation design was used to determine the maximum tolerated cyclophosphamide dose (MTD) in this setting. Three cyclophosphamide dose levels were given: 300 mg/ m2 IV (groupl, 3 dogs), 400 mg/m2 IV (group 2, 12 dogs), and 500 mg/m2 IV (group 3, 13 dogs); and the MTD was 500 mg/m2 IV. Toxicity was common but mild, and the dose-limiting toxicity was myelosuppression, specifically neutropenia. No dog died as a result of treatment-related toxicity. One dog in group 3 developed fever, neutropenia, and presumed sepsis and responded promptly to routine management. No other dog required hospitalization. Lower stage and higher cyclophosphamide dose (both increasing dose [study groups 1-3], and the highest dose [group 3]) compared with the lower doses combined (groups 1 and 2) were significantly associated with longer remission duration (all P < .0001). Median remission duration for dogs in group 3 was 54 weeks, compared with 21 weeks for dogs in groups 1 and 2 combined. Factors associated with longer survival time were lower stage (P = .042) and higher cyclophosphamide dose (both increasing dose [study groups 1-3], and the highest dose [group 3] compared with the lower doses combined [groups 1 and 2]) (P = .027). Median survival time for dogs in group 3 was 139 weeks, compared with 43 weeks and 68 weeks for dogs in groups 1 and 2, respectively.