518 - Concurrent Chronic Inflammatory Demyelinating Polyneuropathy Disguised as Severe Chemotherapy-Induced Peripheral Neuropathy

Case Diagnosis: Chronic Inflammatory Demyelinating Polyneuropathy

Case Description: A 63-year-old female with metastatic ovarian cancer status-post surgery on chemotherapy with paclitaxel and carboplatin presented to the hospital with lower extremity pain, edema, and numbness. She was diagnosed with chemotherapy-induced peripheral neuropathy (CIPN) and discharged to acute rehabilitation. Physiatric assessment showed functional paraplegia with severe bilateral lower-greater-than-upper extremity weakness, stocking-glove pattern numbness, hyporeflexia, and neurogenic bladder and bowel. Presentation was out of proportion with that expected for CIPN, so additional neuropathy workup was pursued. Imaging and labs were largely unremarkable. EMG revealed severe chronic inflammatory demyelinating polyneuropathy (CIDP) with secondary axonal loss in all extremities. The patient was rehospitalized for treatment with IVIG and steroids with improvement in symptoms. 

Discussions: CIPN damages peripheral nerves, causing pain, paresthesia, hypoesthesia, and weakness. Symptom severity is dose-dependent, and onset is hours to days after receiving chemotherapy. Platinum drugs, taxanes, and vinca alkaloids are most likely to cause CIPN. Typically, motor impairments are mild, causing falls and gait abnormalities. Paralysis may occur in severe cases but is uncommon. When neurologic symptoms are out of proportion to the degree of expected weakness, workup should be broadened. CIPN and CIDP both cause weakness, numbness, and paresthesia. However, CIDP causes progressive weakness, areflexia, fatigue, and motor loss. CIPN is a diagnosis of exclusion in cases of severe weakness with improvement within months of discontinuing the offending drug, whereas CIDP worsens without treatment with IVIG, steroids, or plasmapheresis.

Conclusions: Chemotherapy-induced neuropathy should be suspected when symptom onset coincides with treatment with chemotherapy drugs associated with CIPN. However, further evaluation is imperative to identify concurrent processes if examination findings are inconsistent with the discharge diagnosis. Physiatrists are critical in maintaining a high degree of suspicion and working up inconsistent presentations. Identifying treatable secondary diagnoses can prevent the progression of disease and disability and improve functional outcomes.