Brain Magnetic Resonance Imaging White-Matter Lesions and Cerebrospinal Fluid Findings in Patients with Acute Intermittent Porphyria

Abstract

Background: Case reports display similaritiesbetween multiple sclerosis and acute intermittent porphyria (AIP). This study examines whether patients with AIP in general demonstrate white-matter lesions on brain magnetic resonance imaging (MRI) and/or abnormalities in plasma and/or cerebrospinal fluid (CSF) when examined outside attacks. We looked particularly for the presence of oligoclonal bands (OB) of immunoglobulin (Ig) in liquor. Methods:Eight AIP gene carriers without previous episodes of porphyria, mean age 42.8 years (range 30–60), and 8 AIP gene carriers with previous episodes of porphyria, mean age 42.8 years (range 33–62), were examined with brain MRI, venous blood samples and lumbar punctures. Results: Two male AIP gene carriers with previous episodes of porphyria, 58 and 35 years of age, had multiple white-matter, high-signal lesions on T₂- weighted MRI sequences. Two AIP gene carriers without previous episodes of porphyria, 1 male and 1 female, had less than 5 such lesions. No OB were seen in the CSF in any patient, but 1 carrier had an increased level of protein in the CSF. Seven of 16 subjects (44%) had increased levels of HbA1c (>6.0), suggesting protracted hyperglycemia, and 3 further subjects had borderline levels (5.9). Conclusion: T₂-weighted MRI sequences demonstrated multiple white-matter, high-signal lesions in 4 out of 16 AIP gene carriers (25%). No carrier demonstrated OB of Ig in CSF, making it unlikely that demyelinating lesions play a pivotal role in the pathogenesis of CNS symptoms in AIP. Only 1 AIP gene carrier had an increased level of protein in CSF; this contrasts with studies during acute attacks of porphyria. Seven subjects (44%) had abnormally high levels of HbA1c, in spite of the fact that no patient had a previous diagnosis of diabetes mellitus.