Hyperprolactinemia in optico-spinal multiple sclerosis

Objective To clarify the clinical features of MS patients with hyperprolactinemia. Subjects and Methods The serum prolactin level was measured in 67 Japanese patients (19 men and 48 women) with multiple sclerosis (MS) and in 16 patients (4 men and 12 women) with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) using a two-site immunoradiometric assay. Results In the MS patients, 32 were classified as having Asian type MS showing a selective involvement of the optic nerves and spinal cord, while the other 35 were classified as having Western type MS which displayed disseminated central nervous system involvement. In women, the serum prolactin level was found to be significantly higher only in Asian type MS (mean=23.1 ng/ml, n=25) than in HAM/TSP (mean=6.9 ng/ml, n=12) (p=0.0297), while it did not differ significantly in men among the three groups. Hyperprolactinemia was significantly associated with acute relapse involving the optic nerves. All MS patients with hyperprolactinemia (7 women with Asian type MS and 2 women with Western type MS) showed recurrent opticomyelitis either throughout or in the early course of the disease, and also had a higher age of onset, a higher Expanded Disability Status Scale score, a greater visual impairment, and higher cell counts and protein contents in the cerebrospinal fluid than did the normoprolactinemic patients. Conclusion Hyperprolactinemia may be one of the characteristic features of Asian patients with MS who preferentially show the optic nerve involvement.