Synoviocentesis Flashcards
Why is arthrocentesis performed in joint disease workup?
Helps diagnose unknown aetiology of joint disease, joint effusion, infective arthritis, pyrexia of unknown origin & monitors treatment response
What are the common sample types collected for synovial fluid analysis?
Direct smear for cytology
EDTA tube for cell counts & protein analysis
Blood/joint culture medium for bacterial culture
What are the 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 are the key parameters assessed in synovial fluid analysis?
Appearance: Clarity & colour
Viscosity: Polymerisation of hyaluronic acid
Mucin clot test: Assesses hyaluronic acid integrity
Protein levels
Nucleated cell count
Cytology findings
Fill in the joint disease table
How is synovial fluid typically classified?
Non-inflammatory: Degenerative joint disease or trauma
Inflammatory: Based on nucleated cell count, protein, viscosity, and cytology
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 cells, and what do they indicate?
Neutrophils/macrophages that have phagocytised denatured nuclear material
Seen in lupus erythematosus & other immune-mediated diseases
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)
