From the Research
The specificity of CSF protein elevation in Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) is moderate, with approximately 94% of patients showing elevated cerebrospinal fluid protein levels, as reported in the study by 1.
Key Findings
- The study by 1 found that the incidence of elevated levels of total CSF proteins was identical in patients with AIDP and CIDP, reaching 94%.
- The mean level of CSF protein was similar in patients with AIDP and CIDP, 1100 and 1150 mg/l, respectively.
- Local synthesis of CSF oligoclonal IgG was found in 2 patients with CIDP and was not detected in patients with AIDP.
Diagnostic Considerations
- CSF protein elevation in CIDP typically occurs without a corresponding increase in cell count (albuminocytologic dissociation), which helps distinguish CIDP from infectious causes.
- However, CSF protein elevation is not specific to CIDP alone, as it can be seen in other conditions like Guillain-Barré syndrome, diabetic neuropathy, and certain malignancies.
- The protein elevation in CIDP reflects disruption of the blood-nerve barrier due to inflammation and demyelination, allowing proteins to leak into the CSF.
Clinical Implications
- While CSF protein analysis is included in diagnostic criteria for CIDP, it should be interpreted alongside clinical presentation, electrophysiological studies, and sometimes nerve biopsy findings for accurate diagnosis, as normal CSF protein levels do not exclude CIDP.
- A more recent study by 2 found that intrathecal humoral immune response is rare in patients with CIDP, and systemic oligoclonal activation is more frequent, but not significantly different from what was detected in the control groups.
- Another study by 3 found that a mild to moderate pleocytosis in CSF does not exclude the diagnosis of CIDP, especially in patients with a subacute onset of disease.