Appendix B: Basic Laboratory Evaluation and Diagnostic Imaging in NPSLE
A laboratory evaluation to assess SLE disease activity and to exclude other diseases which can cause neurologic symptoms includes:
Blood
- Complete blood cell count including platelet count and smear
- Creatinine or creatinine clearance
- Urinalysis
- Liver function tests
- Electrolytes
- C3, C4, or CH50
- Anti-dsDNA antibodies
- Erythrocyte sedimentation rate or C-reactive protein
- Antiphospholipid antibodies
- Lipid profile, glucose
The blood smear should include a search for schistocytes to exclude thrombotic thrombocytopenic purpura.
Testing for antiphospholipid antibodies should include lupus anticoagulant and anticardiolipin antibodies, isotype and titer. Testing for anti-B 2-glycoprotein antibodies is recommended. Other tests for hypercoagulability states (factor V Leiden, factor XII, protein C and S) may be indicated.
Antineuronal antibodies, antiribosomal P, antilymphocyte, antiglycolipid, antineurofilament, antiglial, antiganglioside, antisphingomyelin, antigalactocerebroside, soluble cytokines are investigational. Antiribosomal P, however, appears to have a high specificity for SLE and may be of diagnostic value in predominantly neuropsychiatric cases without definite diagnosis of SLE.
Lipid profile and glucose are done to establish vascular risk factors. Homocysteine is considered investigational.
CSF
- Cell count
- Protein
- Glucose
- Cultures
- Gram stain and other special stains
- VDRL
- IgG index
- Oligoclonal bands
Other immunologic tests, including antineuronal bodies, antiribosomal P, myelin basic protein, soluble cytokines, and complement are investigational.
Imaging
CT scans should be performed in some acute severe neurologic presentations, if MRI is not readily available. CT is indicated for suspected acute hemorrhage and in patients with contraindications to MRI (intracranial metal, pacemakers, etc.). MRI with gadolinium is more sensitive and used to define site and extent of lesions. A negative MRI result does not rule out CNS lupus, and MRI abnormalities may not be diagnostic of NPSLE. Followup MRIs may be indicated to document progression, improvement, or significance of lesions.
Diffusion and perfusion MRI, MRI spectroscopy, SPECT, PET, and related imaging technologies are still considered investigational.
Digital subtraction angiography and MRA are not as sensitive as standard arteriograms to evaluate vasculopathy.
EEG
Standard EEG indicated in seizures and encephalopathies. Evoked potentials are performed for suspected demyelinating disease. QEEG is investigational.
Miscellaneous
In cerebrovascular disease, echocardiography and carotid artery duplex ultrasound are done to look for a source of thrombus. Transesophageal echocardiography is significantly more sensitive than transthoracic and should be preferred.
