Synoviocentesis Flashcards
Why is arthrocentesis performed?
Joint disease of unknown aetiology
Joint effusion
Multiple joints affected
Possible infective arthritis
Pyrexia of unknown origin
Monitoring treatment response
What sample types are collected for synovial fluid analysis?
Direct smear for cytology
EDTA for cell counts + protein lab analysis
Blood/joint culture medium for culture
What are the different types of joint disease
How can you differentiate between iatrogenic (traumatic) and chronic hemarthrosis in synovial fluid?
Iatrogenic/very acute: Platelets present in smear
Chronic: No platelets, increased WBCs, erythrophagocytosis, haemosiderin, haematoidin
What components of synovial fluid are assessed?
Appearance (clarity + colour)
Viscosity (polymerisation of hyaluronic acid)
Mucin clot test (acetic acid)
Protein
Nucleated cell count
Cytology
Describe the classification of synovial fluid based on analysis
Non-inflammatory (degenerative joint disease or trauma)
Or
Inflammatory (based on nucleated cell count, TP, viscosity, types and appearance of cells
What are important cytological features in synovial fluid smears?
Quality: Cell preservation
Cellularity: Rowing/clusters
Cell population: Lymphocytes, neutrophils, macrophages, synoviocytes, neoplastic cells
Cell morphology: Size, shape, nuclear size, N/C ratio, cytophagy
Background: Granular material, artefacts
What is windrowing in synovial fluid cytology?
Linear alignment of cells due to thick, viscous synovial fluid
What can you see in this synovial fluid sample
Ragocytes – (Arrows)
LE Lupus erythematous cells– (Arrow heads)
What are ragocytes and what do they indicate?
Neutrophils containing cytoplasmic inclusions (phagocytised nuclear material or immune complexes)
Associated with immune-mediated disease (e.g. immune-mediated polyarthritis)
what are LE Lupus erythematous cells?
a neutrophil or macrophage that has phagocytized the denatured nuclear material of another cell
2y/o MN dog
Presented for:
Lethargy
Pyrexia of unknown origin
Reluctance to stand and walk
Hyporexia
On physical examination:
Multiple swollen joints (mostly distally)
What is your diagnosis?
Inflammatory, neutrophilic & non-septic –> multiple joints affected –> Immune-mediated polyarthritis (IMPA)
