Successful treatment of infectious (Salmonella type III: 44) polyarthritis and osteomyelitis in a 4‐week‐old foal

This article describes the acute onset of infectious polyarthritis and osteomyelitis in a 4‐week‐old foal. Analysis of synovial fluid obtained from the left femoropatellar and right tarsocrural joints combined with clinical signs consisting of joint effusion and lameness yielded a diagnosis of septic arthritis. Bacterial culture of synovial fluid from the left stifle revealed Salmonella type III: 44. Rapid, sustained clinical improvement was noted following discontinuation of empirical antimicrobial therapy (potassium penicillin and amikacin sulphate) and initiation of treatment with ceftiofur and ampicillin. The importance of combining knowledge of veterinary pharmacology and microbiology so that appropriate antimicrobials may be selected with regard to the local environment in which they are to eradicate infection is emphasised. Despite frequent reference to amikacin sulphate as an effective antimicrobial for treating infections in foals caused by Salmonella, factors are discussed that explain why amikacin may not be clinically effective for treating infectious arthritis caused by Salmonella.     

Atypical actinobacillosis affecting hind limbs and lungs in a single beef cattle herd

Actinobacillosis usually is a sporadic infection that affects the tongue in cattle (“wooden tongue”) with possible spread to the digestive tract. Two 4‐year‐old Rouge‐des‐Prés cows from a single French beef herd were referred for chronic (2‐6 months) swelling and cutaneous nodules in the distal hind limbs. In addition to cutaneous signs, physical examination disclosed cachexia, lameness, lymphadenitis of the hind limbs, and pneumonia in both cows. Cytologic examination of direct skin smears was inconclusive, and no parasites were observed in examination of multiple skin scrapings. Histopathological examination of skin and lung biopsy specimens identified chronic, diffuse, severe pyogranulomatous dermatitis, associated with Splendore‐Hoeppli phenomenon and intralesional Gram‐negative bacteria. Cultures from skin, lymph nodes, and lungs (both cows were euthanized for welfare reasons) identified a Pasteurellaceae organism, confirmed as Actinobacillus lignieresii by partial sequencing of the rpoB gene. This report emphasizes that actinobacillosis can appear as a small outbreak in cattle with cutaneous and respiratory signs.     

Granulomatous lymphadenitis caused by Talaromyces helicus in a Labrador Retriever

A 3-year-old spayed female Labrador Retriever was presented for right prescapular lymphadenomegaly. Examination of fine-needle aspirates and impression smears of the node revealed many short hyphal structures found within macrophages and extracellularly. Hyphae were approximately 3 μm in diameter, were irregularly septate with nonparallel walls, and had a small clear halo surrounding a partially stained basophilic internal structure. Hyphae were tapered on one end and had oval to pyriform swellings of 7-10 μm on the other, resulting in a bulbous appearance. Fungal elements stained positively with Gomori methenamine silver and Periodic acid-Schiff stains. The dog was euthanized at the owner's request, and necropsy revealed marked peripheral and visceral lymphadenomegaly. Histopathologic examination of lymph nodes confirmed granulomatous lymphadenitis with many fungal hyphae. Fungal culture yielded pure cultures of organisms that failed to produce ascospores or conidia precluding morphologic identification. PCR was performed using pan-fungal primers, ITS-1 and ITS-2, to amplify the intergenic spacer regions of ribosomal RNA; the PCR product was sequenced and a BLAST search of the GenBank databases at NCBI revealed 100% identity of the organism with Talaromyces helicus, the sexual form of Penicillium helicum. Talaromyces helicus has not previously been reported to cause disease in people or animals.     

Bilateral pigmented villonodular synovitis in a dog

Viilonoduiar synovitis is an extremely rare condition of the synovial membrane in the dog. A 10-yearoid, neutered crossbreed was presented with bilateral, progressive hindlimb lameness. Periarticuiar swelling was noted in both stifle joints. No craniocaudal instability was noted. Radiographs showed massive intra-articular soft tissue proliferation in both joints, with no bony involvement. Arthrocentesls was unsuccessful. Exploratory arthrotomy of the left stifle revealed a greatly thickened, florid, proliferative synovial membrane. An Incisional biopsy was carried out and the histopathological diagnosis was chronic active viilonodular synovitis. A radical synovectomy was carried out in the right stifle joint 10 days later. Corticosteroid treatment was initiated 10 days after the second surgery and continued for six weeks, with a continuous clinical improvement. Eighteen months after discontinuation of the steroid therapy, the owners reported no recurrence of clinical signs although a mild stiffness was still present.     

Osteosarcoma in the proximal humerus of a mare

A 15‐year‐old Quarter Horse mare was examined for significant and progressive lameness in the right front limb. On physical examination, muscle atrophy over the scapular and pectoral regions were noted. A pain response was elicited on palpation of the scapulohumeral joint. No other abnormalities were noted on examination of the limb. Diagnostic nerve blocks ruled out a source of lameness in the distal limb. Arthrocentesis of the scapulohumeral joint was performed and results were within normal limits. Radiographs of the right scapulohumeral joint revealed an extensive, aggressive bone lesion in the proximal humerus, suspected to be an osteosarcoma. After a course of nonsteroidal anti‐inflammatory therapy, minimal improvement to the lameness was noted. The owner elected to subject the horse to euthanasia due to the lack of significant response to treatment. Post mortem radiographic and histological examinations determined a definitive diagnosis of an osteosarcoma in the proximal humerus.     

Multiple joint metastasis of a transitional cell carcinoma in a dog

An 8‐year‐old castrated male hound mix was referred to the Purdue University Veterinary Teaching Hospital for severe lameness, pollakiuria, and dyschezia. On presentation, the dog was nonweight bearing on the right rear limb and the right carpus was diffusely swollen. Synovial fluid analysis from the right carpus revealed a population of epithelial cells displaying marked anisocytosis, anisokaryosis, multinucleation, and prominent, variably sized nucleoli. A metastatic carcinoma with presumed prostatic or urothelial origin was diagnosed based on cytomorphology. Subsequent cytologic evaluation of peripheral lymph nodes revealed the presence of a similar neoplastic population. The dog was euthanized and synovial fluid from both stifle joints, as well as impression smears of the prostate gland, were collected. Carcinoma cells were identified in each stifle joint and in the prostate gland. Immunocytochemistry was performed on synovial fluid smears from 2 of the joints (right stifle and right carpus) and on impression smears of the prostate gland. The neoplastic population in the joints and prostate gland showed strong immunoreactivity to uroplakin III, a urothelial marker, indicating metastasis of a transitional cell carcinoma to multiple joints. In addition, evidence for epithelial to mesenchymal transition was identified using cytokeratin, an epithelial marker, and vimentin, a mesenchymal marker. A necropsy was performed and histopathology confirmed the presence of metastatic transitional cell carcinoma in various tissues. This case illustrates the importance of considering metastatic disease when a patient is presented with severe lameness and joint pain, and the clinical utility of synovial fluid cytology for diagnosis of metastasis in these cases.     

Effects of intra-articular administration of dimethylsulfoxide on chemically induced synovitis in immature horses

The effects of intra-articular administration of dimethylsulfoxide (DMSO) on chemically induced synovitis in the middle carpal joint of 6 weanling horses were evaluated. Following aseptic collection of synovial fluid, the middle carpal joint of each forelimb was injected with 50 mg of Na-monoiodoacetate to induce synovitis. Eight days after injection, synovial fluid was obtained and the right middle carpal joints were injected with 2 ml of 40% DMSO in lactated Ringer solution. The corresponding joints of the left limb (control) were injected with 2 ml of lactated Ringer solution. Sampling and treatments were repeated on post-injection days 11 and 14, for a total of 3 treatments. Horses were visually evaluated daily for lameness and joint effusion. Synovial fluid was evaluated for color and clarity, differential and total WBC count, total protein content, and hyaluronic acid concentration. The Kaegi gait analysis system provided an objective assessment of lameness prior to inducing synovitis, again on day 7, and on day 17. At necropsy (day 17), synovial fluid, synovial membrane, and articular cartilage specimens were collected. Joint effusion was evident 12 hours after injection of Na-monoiodoacetate in all joints. Mild lameness was evident at 24 hours; however, the lameness resolved by 72 hours. Objective assessment of lameness did not reveal significant differences between treatment or control limbs. Hyaluronic acid concentrations increased significantly (P = 0.023) above baseline values in most joints over the study period. Synovial fluid WBC counts increased significantly (P = 0.002) following Na-monoiodoacetate injection and remained significantly (P = 0.002) above baseline values throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antebrachial metacarpal arthrodesis for fusion of deranged carpal joints in two dogs

Congenital malformation of the carpal joint in a young dog resulted in a progressive lameness. Traumatic disruption of the carpus in another dog resulted in carpal bone necrosis, infection, and chronic instability. Radial metacarpal arthrodesis was performed in both dogs. The diseased carpal bones were excised, sparing the accessory carpal bone in both dogs. Radial metacarpal arthrodeses were then performed, using bone plate fixation. In the dog with the malformed limb, the gait had improved, but intermittent lameness was still present 8 months later because of an associated malarticulation of the cubital joint. The dog with the traumatized carpus had little or no lameness associated with normal activity for 32 months.     

Cladosporium cladosporioides‐complex infection in a mixed‐breed dog

A 3‐year‐old female mixed‐breed dog was referred with a 2‐day history of serious dyspnea, coughing, lethargy, anorexia, and a low‐grade right anterior lameness. At presentation, the dog had an increased respiratory rate, dull heart and lung sounds, and cyanotic mucous membranes. It was hyperthermic and slightly dehydrated. Laboratory findings showed mild neutrophilia with a left shift, while serum biochemistry variables were in the normal range. However, urinalysis revealed mild proteinuria and rare erythrocytes and leukocytes on sediment examination. Thoracic radiographs showed a diffuse mixed interstitial and alveolar pattern with an air bronchogram, while appendicular radiographs showed a right humeral interrupted brush‐like periosteal reaction. Thoracic ultrasonography revealed mediastinal lymph node enlargement. Cytology from a fine‐needle aspirate of mediastinal lymph nodes revealed a pyogranulomatous lymphadenitis with numerous fungal hyphae. Culture on Sabouraud dextrose agar isolated dark fungal colonies with microscopic features consistent with Cladosporium spp. Sequencing of the internal transcribed spacer region identified the fungus as a species of the Cladosporium cladosporioides‐complex.     

MRI FEATURES OF GASTROCNEMIUS MUSCULOTENDINOPATHY IN HERDING DOGS

Pelvic limb lameness that was localized clinically to the lateral gastrocnemius head was observed in dogs without history of trauma. The aim of this retrospective study was to describe magnetic resonance imaging (MRI) findings of this condition. Nine dogs were identified, eight Border Collies and one Australian Shepherd. They all had chronic pelvic limb lameness; no signs of joint effusion or instability were present. In MR images there was high signal intensity in the lateral head of the gastrocnemius muscle around the sesamoid bone in T2‐weighted, T2^*‐weighted, and STIR images and an iso‐ to mildly hyperintense signal in T1‐weighted images with marked contrast enhancement. The abnormal signal intensity most likely represents a myotendinous strain. The breed affiliation to Border Collies is striking, and a relation to biomechanical forces or motion pattern may be possible. Except for the dog with the most extensive lesion all dogs had an excellent outcome.     

Diagnosis and management of Candida utilis infectious arthritis in a Standardbred filly

A 3‐year‐old Standardbred filly was admitted to the hospital for evaluation and management of previously diagnosed infectious arthritis of the right metacarpophalangeal joint (MCPJ). Candida utilis was isolated from multiple synovial samples submitted for bacterial culture and susceptibility. Following treatment with systemic and intra‐articular fluconazole and regional limb perfusion with amphotericin B and a second arthroscopic debridement the lameness improved and subsequent cultures were negative for bacterial or fungal growth. Infectious fungal arthritis should be a differential diagnosis for atypical or unresponsive joint infections especially in horses previously treated with a combination of intra‐articular corticosteroids and antibiotics.     

Endogenous mycotic endophthalmitis in a dog with candiduria and Evans syndrome

This report describes the clinical presentation, diagnosis, histologic lesions, and outcome of endogenous mycotic endophthalmitis secondary to candiduria in a three‐year‐old female spayed Dachshund. The dog was being treated for Evans syndrome for one month prior to being diagnosed with candiduria and fibrinous uveitis OS. The left eye was enucleated due to secondary glaucoma, and the fungal urinary tract infection was treated successfully. Uveitis developed in the contralateral eye with relapse of the urinary tract infection in the following weeks. The right eye was medically managed until secondary glaucoma developed and was subsequently enucleated. Histopathology of both eyes showed evidence of endophthalmitis with intralesional fungal organisms, consistent with Candida spp. Ocular candidiasis is rare in dogs. To the authors' knowledge, this is the first report of endogenous mycotic endophthalmitis with concurrent candiduria in a dog.     

Subchondral bone cyst of the apical portion of the proximal sesamoid bone as a cause of severe lameness in a Warmblood filly

A 20‐month‐old Warmblood filly was evaluated for acute onset of a nonweightbearing lameness and swelling of the left hindlimb. Clinical and lameness evaluation and diagnostic intrasynovial anaesthesia isolated the lameness to the left hind metatarsophalangeal region. Radiography and ultrasonography revealed a subchondral cystic lesion of the apical portion of the lateral proximal sesamoid bone associated with oedema and synovial effusion of the metatarsophalangeal joint. Arthroscopic surgical debridement of the subchondral cystic lesion resulted in immediate post operative improvement in the lameness score. Rest and controlled exercise achieved complete resolution of the lameness with the filly being able to start training without apparent lameness. Subchondral cystic lesions of the proximal sesamoid bones can be a cause of nonweightbearing lameness. Surgical debridement resulted in complete resolution of the lameness with a favourable outcome in this case.     

Synovial Hemangioma in a Dog

Objective— To report arthroscopic diagnosis and treatment of synovial hemangioma in a dog.
Study Design— Case report.
Animal— Standard Poodle (8-year-old neutered male).
Methods— A soft tissue density mass observed radiographically in the left stifle joint of a dog with a 2-month history of recurrent lameness, hemarthrosis, and a slight cranial drawer sign, was located by diagnostic arthroscopy and surgically excised via arthrotomy.
Results— Histologic evaluation revealed tissue composed of variably sized cavernous vascular spaces filled with erythrocytes that were considered compatible with synovial hemangioma.
Conclusions— In this dog, synovial hemangioma evident as a soft tissue mass on radiographs was associated with chronic lameness and hemarthrosis, and resolved with surgical excision.
Clinical Relevance— Synovial hemangioma, although seemingly rare in dogs, should be considered in the differential diagnosis for nontraumatic, recurrent lameness, and unresponsive to anti-inflammatory therapy when there is a circumscribed intracapsular soft tissue mass evident radiographically together with hemarthrosis.     

Granulomatous meningoencephalitis associated with Sporobolomyces roseus in a dog

A German Shepherd Dog was evaluated for clinical signs of multifocal, progressive brain disease. Despite supportive care, the dog died shortly after hospital admission. Granulomatous meningoencephalitis with intralesional fungal hyphae was diagnosed postmortem. The fungus was identified as Sporobolomyces roseus by polymerase chain reaction amplification and sequencing of the ITS2 region.     

Unusual systemic signs in a dog with sterile neutrophilic-macrophagic lymphadenitis and nodular panniculitis

A 7 mo old female English springer spaniel was presented with diarrhea, vomiting, apathy, and hyperthermia. Further examinations revealed generalized lymphadenomegaly consistent with sterile neutrophilic-macrophagic lymphadenitis and pulmonary involvement. Subcutaneous nodules developed one day after presentation. Histology was consistent with sterile idiopathic nodular panniculitis and vasculitis. No infectious organism was isolated. The dog responded to prednisolone, but relapsed during medication tapering. Cyclosporine had to be added to control the disease. No further relapse had occurred 98 wk after the first presentation. This is an unusual presentation of a systemic sterile neutrophilic-macrophagic lymphadenitis with nodular panniculitis and vasculitis associated with gastrointestinal and pulmonary signs.     

Supraspinatus tendinosis associated with biceps brachii tendon displacement in a dog

A 4-year-old spayed female Australian Cattle Dog (Blue Heeler) was evaluated because of right forelimb lameness of 5 months' duration. Orthopedic evaluation revealed signs of pain localized to the cranial aspects of both shoulder joints. Via magnetic resonance imaging, the mass of the supraspinatus tendon insertion in both shoulder joints was increased, compared with findings in cadavers of clinically normal dogs; additional imaging procedures revealed that, compared with clinically normal tendons, the tendon had increased signal intensity that was consistent with increased fluid content. The increased supraspinatus tendon mass in each shoulder joint was associated with medial displacement of the biceps brachii tendon, which was more severe in the right limb. Arthroscopic evaluations of both shoulder joints revealed no abnormalities. The dog underwent surgery, and the abnormal parts of the tendons were resected. The most prominent finding on histologic examination of excised tissues was severe myxomatous degeneration. The lameness resolved, and at 22 months after surgery, the dog was reported to have had no recurrence of lameness. The clinical signs and histologic appearance of the tendons in this dog strongly resemble findings associated with tendinosis in humans. Decompression of the biceps brachii tendon may have contributed to the successful outcome after surgery in this dog. Supraspinatus tendinosis should be considered among the differential diagnoses in dogs with uni- or bilateral forelimb lameness.     

ULTRASONOGRAPHIC FINDINGS IN 38 HORSES WITH SEPTIC ARTHRITIS/TENOSYNOVITIS

Septic arthritis/tenosynovitis in the horse can have life‐threatening consequences. The purpose of this cross‐sectional retrospective study was to describe ultrasound characteristics of septic arthritis/tenosynovitis in a group of horses. Diagnosis of septic arthritis/tenosynovitis was based on historical and clinical findings as well as the results of the synovial fluid analysis and/or positive synovial culture. Ultrasonographic findings recorded were degree of joint/sheath effusion, degree of synovial membrane thickening, echogenicity of the synovial fluid, and presence of hyperechogenic spots and fibrinous loculations. Ultrasonographic findings were tested for dependence on the cause of sepsis, time between admission and beginning of clinical signs, and the white blood cell counts in the synovial fluid. Thirty‐eight horses with confirmed septic arthritis/tenosynovitis of 43 joints/sheaths were included. Degree of effusion was marked in 81.4% of cases, mild in 16.3%, and absent in 2.3%. Synovial thickening was mild in 30.9% of cases and moderate/severe in 69.1%. Synovial fluid was anechogenic in 45.2% of cases and echogenic in 54.8%. Hyperechogenic spots were identified in 32.5% of structures and fibrinous loculations in 64.3%. Relationships between the degree of synovial effusion, degree of the synovial thickening, presence of fibrinous loculations, and the time between admission and beginning of clinical signs were identified, as well as between the presence of fibrinous loculations and the cause of sepsis (P ≤ 0.05). Findings indicated that ultrasonographic findings of septic arthritis/tenosynovitis may vary in horses, and may be influenced by time between admission and beginning of clinical signs.     

Management of an infected cementless cup with prosthetic retention and antibiotic therapy in a dog

A two‐year‐old Rottweiler presented for acute onset of a right hindlimb lameness 20 weeks after a cementless total hip replacement (THR) and 16 weeks after open reduction to address luxation of the THR. Radiographs revealed periosteal proliferation of the medial acetabulum and a stable implant. Synovial fluid cytology was consistent with inflammatory joint fluid. Treatment consisted of surgical debridement and intravenous and oral antibiotics. THR implants were not removed. Culture of tissue removed from the THR site yielded growth of Pseudomonas and Staphylococcus species. Lameness resolved 2 months after surgery. Twenty months after surgery, the dog was exercising normally with no clinical lameness and pelvic radiographs revealed no evidence of implant loosening and markedly decreased periosteal reaction. To the authors’ knowledge, this is the first report of an infected THR site successfully treated without prosthesis explantation in the dog.     

Gastrointestinal pythiosis with concurrent presumptive gastrointestinal basidiobolomycosis in a Boxer dog

A 2‐year‐old female spayed Boxer dog was presented for a 1‐month history of progressive hemorrhagic diarrhea with tenesmus and weight loss despite trial courses of antibiotics and diet change. Abdominal ultrasound revealed severe, focal thickening, and loss of normal architecture of the colonic wall with abdominal lymphadenomegaly. Dry‐mount fecal cytology, performed on several consecutive days, consistently revealed numerous, round, 16‐20 μm structures with basophilic, granular content, and a thin cell wall. Transmission electron microscopy identified these structures as fungi. Culture, polymerase chain reaction (PCR), and sequencing of the internal transcribed spacer, D1/D2 regions, and DNA‐directed RNA polymerase II core subunit (RPB2) confirmed the presence of Basidiobolus microsporus in the feces. Biopsies collected via ileocolonoscopy revealed marked, multifocal, chronic, neutrophilic, and eosinophilic ileitis and colitis with ulceration, granulation tissue, and intralesional hyphae (identified with Gomori methenamine silver stain). A Pythium enzyme‐linked immunosorbent assay and Pythium‐specific PCR performed on the formalin‐fixed paraffin‐embedded biopsy specimens were positive while Basidiobolus‐specific PCR was negative, thus confirming a diagnosis of pythiosis. This report describes a fatal case of colonic and intestinal pythiosis with the presence of fecal Basidiobolus sp. spores, suggestive of concurrent gastrointestinal basidiobolomycosis.