Unraveling the Misdiagnosis: Chronic Immune Sensory Polyradiculopathy Masquerading as Functional Neurologic Disorder
Objective:
To highlight diagnostic challenges and risk of functional misattribution in a young patient with presumed chronic immune sensory polyradiculopathy (CISP) within the spectrum of Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP).
Background:
CISP is a rare proximal sensory variant of CIDP characterized by immune-mediated involvement of sensory nerve roots. Patients may demonstrate normal MRI and electrodiagnostic studies, with elevated cerebrospinal fluid (CSF) protein often representing the primary objective abnormality. Subtle findings increase the risk of delayed diagnosis or referral for functional neurologic evaluation.
Design/Methods:
We retrospectively reviewed the clinical course of a female patient with longitudinal follow-up from symptom onset at age 12 through age 24, including examination findings, imaging, electrodiagnostics, CSF analysis, and treatment response.
Results:
The patient developed progressive left lower extremity numbness in 2014, followed by severe neuropathic pain, sensory ataxia, and rapid left-sided weakness. MRI revealed only mild lumbar disc bulging. CSF protein was elevated (43 mg/dL). Initial NCS (2016) demonstrated prolonged latencies and slowed conduction velocities; repeat studies in 2019 were normal. By 2018, examination showed 4/5 strength in the left extremities, hemisensory loss to multiple modalities, asymmetric reflexes (1+ LUE; 2+ RUE and BLE), and impaired gait without upper motor neuron signs. Due to largely nondiagnostic testing, she enrolled in a functional neurologic rehabilitation program to regain ability to walk, though no formal diagnosis was established.
After transient response to oral steroids, beginning IVIG during November 2019 (140 g over 3 days) produced near-complete symptom resolution within 2–3 days, with recurrence after three weeks. Presently, ongoing immunotherapy every three weeks has resulted in sustained functional improvement.
Conclusions:
This case underscores the risk of functional misattribution in patients with immune-mediated sensory polyradiculopathy and minimal objective findings. Reproducible response to immunotherapy supported a presumed CISP-spectrum disorder despite inconsistent electrodiagnostics. Early recognition of atypical CIDP variants may prevent delayed treatment and prolonged disability.
Generative AI Usage
No, did not use generative AI in the drafting or editing in this abstract.
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