CIDP Diagnostic Pitfalls and Perception of Treatment Benefit
Allen JA, Lewis RA
Chronic inflammatory demyelinating polyneuropathy (CIDP) is an immune-mediated peripheral nerve disorder that is challenging to diagnose, particularly in the absence of reliable biomarkers. The goals of this retrospective study were to examine the diagnosis and misdiagnosis of CIDP, and to determine common errors that result in its misdiagnosis. The investigators reviewed diagnostic and treatment information from records of 59 consecutive patients referred to them with a diagnosis of CIDP, using the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria to determine a CIDP diagnosis.
Nearly half (47%) of the patients referred with a diagnosis of CIDP did not meet minimal EFNS/PNS criteria for a diagnosis of CIDP. Most of these patients had some type of large-fiber neuropathic process, but 22% of them had generalized chronic pain syndromes without any of the trademark clinical or electrophysiologic characteristics of CIDP. Although 44% patients satisfied minimal EFNS/PNS clinical criteria, each of them would be considered atypical under the EFNS/PNS definition because they had pure motor, pure sensory, or distal predominant clinical features. Only four of these patients also satisfied EFNS/PNS electrodiagnostic criteria.
Half (50%) of the patients without CIDP had cytoalbuminologic dissociation in their cerebrospinal fluid (CSF), which is a common characteristic in CIDP, but protein elevations were typically mild. Only two of these patients had CSF protein levels exceeding 100 mg/dL. Although findings were varied on nerve conduction testing in patients without CIDP, these typically showed demyelinating features more consistent with a process other than CIDP. Even when misdiagnosed with CIDP, patients often reported improvements after receiving immunotherapy.