Syphilitic dementia and lipid metabolism

Chronic syphilitic infection may lead to dementia. It is in general paresis (GP), which is the major late form of neurosyphilis, that cognitive impairment frequently occurs. The association between lipid metabolism and GP is unclear.

In this study, serum lipids were studied in 188 GP patients, in 241 syphilitic patients without neurosyphilis and in 539 healthy controls. The Mini-Mental State Examination (MMSE) was tested in all GP patients. Thirty-five GP patients had a follow-up evaluation 3 months after penicillin treatment.

Significantly lower apolipoprotein A-I (apoA-I) levels were found in GP and in syphilitic patients without neurosyphilis compared to controls. In the 25-44-year-old groups, the male syphilitic patients without neurosyphilis had lower serum apoA-I levels and higher apolipoprotein B (apoB)/apoA-I ratios compared with female patients. A follow-up evaluation of 35 GP patients 3 months after penicillin treatment showed a significant positive correlation between increased apoA-I levels and MMSE scores.

Abnormal apoA-I metabolism may be associated with the decline of cognitive performance. Long-term decrease of apoA-I level and higher apoB/apoA-I ratio may be contributing factors in syphilitic dementia. These results suggest a similar overlap between syphilitic dementia and lipid metabolism to that occurring in Alzheimer's disease.