Normal Pressure Hydrocephalus Exacerbation in Multiple Myeloma: Case Report

Background Neurological complications of multiple myeloma typically include light chain related peripheral neuropathy, hypercalcemia, amyloidosis, and hyperviscosity syndrome. Central nervous system involvement in multiple myeloma is rare. Possible routes of involvement include direct osseous spread or hematogenous spread of extra medullary disease. There can also be effects due to elevated cerebrospinal fluid (CSF) protein levels and subsequent increase of CSF pressure, either from proteins produced by myeloma itself or from blood brain barrier dysfunction and leakage of serum protein into CSF space. Case report The patient is a 76-year-old white female who presented with three years of magnetic gait as well as imbalance. She was able to control urination, but would have urge incontinence if she was too slow to walk to the bathroom. She reported no relevant family history. There was no smoking history. Her past surgical history is hysterectomy. She was alert and oriented to person, place, and time. Her delayed recall was 3/3. She exhibited unsteady, wide based, magnetic gait. Her neurological examination was otherwise normal. Initial lumbar puncture was normal. There was no improvement of gait after lumbar puncture. Carbidopa levodopa 25/100 mg tablets three times a day led to no improvement. She was subsequently diagnosed with smoldering multiple myeloma given 30% plasma cells in bone marrow which were Kappa and CD138 positive and after drop in hemoglobin and platelet was placed on daratumab regimen for IgA Kappa multiple myeloma. One year after the initial evaluation, she was evaluated in the emergency room with inability to ambulate, confusion, and urinary incontinence. As her platelets recovered to normal, lumbar puncture was performed, showing opening pressure of 60 cm H20, Protein >4,000 mg/dl (normal 15-45 mg/dl), but with negative CSF cytology. Pleural fluid cytology revealed plasma cells. She received further chemotherapy with return of normal mental status but remains with urinary incontinence and unable to ambulate. Discussion Possible CNS involvement by myeloma was implied from worsening gait disturbance and elevated CSF protein. IgA myeloma is more likely to have CNS involvement but she doesn’t formally qualify for Bing Neely syndrome given absence of proof of plasma cells in the cerebrospinal fluid. It is possible that her neurological symptoms were due to blood brain barrier dysfunction.