What is your diagnosis? Synovial fluid from a dog

Abstract

A 4-year-old, female neutered Alaskan Malamute was presented with a 10-week history of reluctance to stand up and walk, which was intermittent and partially responsive to nonsteroidal anti-inflammatory drugs and steroids. The dog had no other signs of disease and was current on vaccinations (last vaccine 6 months before presentation) and parasite control. The dog was slightly lethargic and reluctant to move and stand up during consultation. It was painful when trying to stand and walked with a stiff gait. Physical examination showed severe pain in several joints, especially the carpi. CBC, biochemistry profile, and urine analysis were unremarkable. No abnormalities were identified on abdominal ultrasound examination and thoracic radiographs. Radiographs from the carpi did not show signs of erosion or other bone abnormalities. Synovial fluid was obtained by fine-needle aspiration (FNA) from multiple joints (both carpi, elbows, and stifles), and all samples presented similar findings. The synovial fluid appeared cloudy and had a decreased viscosity with poor mucin clot formation. Total proteins measured by refractometry ranged from 3.7-4.1 g/dL and cellularity ranged from 4000-7300 nucleated cells/uL. Cytologic findings of a cytocentrifuge preparation are shown in Figure 1. Figure 1. Cytocentrifuged preparation of synovial fluid from the left carpus of a dog. Modified Wright stain. 940 objective.

Preanalytical Considerations for Joint Fluid Evaluation

“…Clinical signs, antinuclear antibody titers, and response to treatment also must be taken into account. 33 In addition, if rickettsial infection is suspected, it is recommended to perform both acute and convalescent serologic titers and polymerase chain reaction tests, as all tests can produce false negatives depending on the specific etiologic agent and stage of infection. Rarely, morulae can be observed in synovial fluid samples but specific identification of the rickettsial agent cannot be confirmed on cytology alone.…”

Presumed lupus erythematosus cells identified in bronchoalveolar lavage fluid from a Mexican Hairless dog

“…Additional contributing factors include ultraviolet light exposure (dermatologic signs), genetic predisposition, and certain drugs . Clinical signs are typically associated with inflammation of multiple body systems including musculoskeletal inflammation (polyarthritis), skin lesions, hematopoietic changes (anemia and thrombocytopenia), renal conditions (glomerulonephritis), various neurologic manifestations, and rarely, cardiopulmonary inflammation (pleuritis or pericarditis) . The inheritance of SLE in dogs has been previously defined and specific immunologic alterations have been reported.…”

Diagnosis of systemic lupus erythematosus in a dog with an atypical presentation of pleuritis

“…9 In people, they have been described in synovial fluid, body cavity effusions, bone marrow, peripheral blood, bronchoalveolar lavage (BAL) and cerebrospinal fluid. 8,10,11 Similarly, LE cells are an uncommon finding in domestic species; they are rarely observed in synovial fluid, 5 and have been reported in the BAL of a dog. 12 While the diagnosis of SLE remains challenging due to its non-specific manifestation, this case report illustrates the insidious nature of SLE as 'the great imitator' of other diseases.…”

“…2 The clinical syndrome is characterised by inflammation involving several body systems, including polyarthritis, anaemia, thrombocytopenia, glomerulonephritis, neurological signs and serositis. [3][4][5][6] The underlying aetiology and mechanism of the pathogenesis remain unclear. The American College of Rheumatology (ACR) introduced a classification system with 11 criteria included to help diagnose SLE.…”

“…Depending on the site of deposition of these circulating immune complexes in various organs or tissues, they can induce tissue inflammation and damage, leading to a variety of clinical signs attributable to numerous body systems 2 . The clinical syndrome is characterised by inflammation involving several body systems, including polyarthritis, anaemia, thrombocytopenia, glomerulonephritis, neurological signs and serositis 3–6 …”