From the Guidelines
The diagnostic workup for suspected Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) should include a comprehensive neurological examination, nerve conduction studies, cerebrospinal fluid analysis, and blood tests. Begin with a detailed clinical history focusing on symptom progression, symmetry, and sensory/motor involvement. Nerve conduction studies are essential and typically show demyelinating features such as conduction blocks, temporal dispersion, and prolonged distal latencies in multiple nerves 1. Cerebrospinal fluid analysis often reveals elevated protein levels (>45 mg/dL) with normal cell counts, known as albuminocytologic dissociation. Blood tests should include complete blood count, comprehensive metabolic panel, HbA1c, thyroid function, vitamin B12, serum protein electrophoresis, and immunofixation to rule out other causes. Additional tests may include anti-ganglioside antibodies, anti-MAG antibodies, and HIV testing. In atypical cases, nerve biopsy may be considered, showing demyelination with inflammatory infiltrates. MRI of spinal roots and plexuses can show nerve root enhancement or thickening.
Some key points to consider in the diagnostic workup include:
- Nerve conduction studies and electromyography can identify mononeuropathies, differentiate multiple mononeuropathy versus polyneuropathy and distinguish axonal from demyelinating neuropathies 1
- Cerebrospinal fluid analysis is useful in inflammatory demyelinating polyradiculoneuropathy 1
- Nerve biopsy is rarely needed to establish the diagnosis, but can be useful in atypical cases 1
- A comprehensive approach is necessary because CIDP is primarily a clinical diagnosis supported by electrodiagnostic and laboratory findings, and early diagnosis enables prompt treatment with immunomodulatory therapies to prevent axonal damage and disability.
It's worth noting that while the provided evidence includes studies on other conditions, such as eosinophilic granulomatosis with polyangiitis, the most relevant information for the diagnosis of CIDP comes from the study on neuropsychiatric manifestations of systemic lupus erythematosus 1 and the more recent study on eosinophilic granulomatosis with polyangiitis 1. However, the latter study does not provide specific guidance on the diagnosis of CIDP, and therefore the recommendations are based on the general principles of diagnosing demyelinating neuropathies.
From the Research
Diagnostic Workup for Suspected CIDP
The diagnostic workup for suspected Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) involves a combination of clinical characteristics, electromyography, nerve conduction studies, and elevated protein in cerebrospinal fluid 2. The following are key components of the diagnostic workup:
- Clinical history and neurological exam to identify progressive weakness and sensory loss
- Electrophysiological evaluation, including electromyography (EMG) and nerve conduction studies (NCS), to demonstrate demyelinating changes 3
- Cerebrospinal fluid (CSF) examination to reveal cytoalbuminologic dissociation or elevated protein levels 2, 4, 5
- Imaging studies, such as magnetic resonance imaging (MRI), to show lumbosacral root or plexus enhancement 6
- Nerve biopsy, in some cases, to confirm demyelination and axonal degeneration 5
Special Considerations
In some cases, patients with clinical features of CIDP may not have evidence of demyelination on NCS, but may still have supportive laboratory findings, such as elevated CSF protein or MRI abnormalities 6. In these cases, a trial of immunomodulating treatment may be considered, particularly if there is MRI lumbosacral root or plexus enhancement.
Key Findings
The diagnostic workup for CIDP should include a combination of clinical, electrophysiological, and laboratory evaluations to confirm the presence of demyelination and rule out other conditions. The following key findings support the diagnosis of CIDP:
- Reduced conduction velocity with bilateral and symmetrical sensory and motor involvement on EMG/ENG 4
- Elevated protein in CSF, with or without cytoalbuminologic dissociation 2, 4, 5
- Demyelinating changes on NCS, although not always present 3, 6
- Clinical features of progressive weakness and sensory loss, with or without cranial nerve involvement 2, 4, 3