Coexisting Inflammatory and Hereditary Neuropathies: A Review

The concurrent presentation of acquired neuropathy and hereditary neuropathy is both diagnostically challenging and important to recognize. This review focuses on cases of concurrent chronic inflammatory demyelinating polyneuropathy (CIDP) and Charcot-Marie-Tooth (CMT) disease. Two cases of patients diagnosed with both CIDP and CMT1A are presented, and reported cases of CMT1A, CMT1B, and CMTX and CIDP overlap are reviewed. Although clinical history and examination have primacy, electrodiagnostic (EDx) testing and other supportive tests can help identify cases with dual pathology. Features that raised concern for superimposed inflammatory neuropathy in all cases included a combination of rapidly progressive, proximal or asymmetric weakness and sensory symptoms. The diagnosis of CIDP in these cases was supported by a combination of albuminocytologic dissociation in cerebrospinal fluid (63% of cases), EDx features of acquired demyelination on EDx (conduction block in 69% of cases, asymmetric slowing of conduction velocities), inflammatory changes on nerve biopsy (58%), and response to treatment (84%). Patients with CMT1X and CIDP had the highest rate of immunotherapy treatment failure, which may reflect misdiagnosis, as CMT1X has been associated with features of acquired segmental demyelination, such as conduction block. Neuromuscular ultrasound is the newest diagnostic test to differentiate CIDP from CMT and can be helpful in cases where motor and sensory nerve responses are absent on EDx testing.