Differential Diagnosis for CSF Gamma Restriction Bands
The presence of well-defined gamma restriction bands in the CSF that are not present in the serum, along with identical bands in both CSF and serum, suggests a condition affecting the central nervous system (CNS) with possible systemic involvement. Here's a categorized differential diagnosis:
Single most likely diagnosis
- Multiple Sclerosis (MS): The presence of oligoclonal bands (OCBs) in the CSF that are not present in the serum is a hallmark of MS, indicating intrathecal immunoglobulin synthesis. The identical bands in both CSF and serum could represent a systemic immune response or the presence of these bands in the serum due to the breakdown of the blood-brain barrier.
Other Likely diagnoses
- Neurosyphilis: This condition can also present with OCBs in the CSF, although it's less common than in MS. The presence of identical bands in the serum and CSF might be seen in cases of active systemic infection.
- Subacute Sclerosing Panencephalitis (SSPE): A rare chronic infection of the CNS caused by a defective measles virus, which can lead to the production of OCBs in the CSF.
- Chronic Inflammatory Demyelinating Polyneuropathy (CIDP): Although primarily a peripheral nervous system disorder, some forms of CIDP can have CNS involvement and might show OCBs in the CSF.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Lymphomatous or Leukemic Meningitis: The presence of abnormal gamma restriction bands could be indicative of CNS involvement by a lymphoma or leukemia, which would require immediate and aggressive treatment.
- Infectious Meningitis (e.g., Tuberculous, Fungal): Certain infections can lead to the production of OCBs in the CSF, and missing these diagnoses could have severe consequences.
Rare diagnoses
- Neuro-Behçet's Disease: A form of vasculitis that can affect the CNS and might present with OCBs in the CSF.
- Sjögren's Syndrome with CNS Involvement: This autoimmune disorder can rarely affect the CNS and might show OCBs in the CSF.
- HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP): A rare condition caused by the human T-lymphotropic virus 1 (HTLV-1), which can lead to demyelination and the presence of OCBs in the CSF.