Leptomeningitis in a person with radiologically isolated syndrome and latent tuberculosis. A case report with implications for clinical research

A 39-year-old man, followed with serial MRI of CNS for a radiologically isolate syndrome (RIS, a recently described condition considered a subclinical form of MS), was hospitalized for the occurrence of a leptomeningitis. Routine blood tests and contrast enhanced total body CT scan were unremarkable. Cerebrospinal fluid (CSF) examination showed increase of cells (22 mononuclear cells/mm3), albumin (294 mg/L), immunoglobilins G (161 mg/L) and Link Index (1.9), with 17 oligoclonal bands. Microbiological examinations of CSF (including those for Koch’s Bacillus) were negative. The Mantoux reaction and the QuantiFERON test were positive, featuring a latent tuberculosis (TB). The patient started prophylaxis with rifampicin and isoniazid for four months, until a new MRI showed the disappearance of the leptomeningeal enhancement, and the stability of white matter brain and spinal cord lesions. Two other MRI scans showed a new brain Gd-enhancing lesion nine month after anti-tubercular therapy and, after additional six months, new cerebral and spinal cord areas. This case provides the following suggestions about the effects of TB infection and related therapies on the underlying autoimmune status: the infection, while actively present, did not exacerbate the RIS condition; the worsening nine months after the prophylaxis discontinuation might have been the ‘natural’ evolution of RIS condition. Alternative speculative hypotheses include a remote effect of the infection, of isoniazid (that was reported in some cases to trigger MS), or the result of the clearance of the infection itself. Irrespective of the existence of any interaction between RIS and TB infection, It seems important to collect cases with MS-related diseases and concomitant infections, that may provide clues about disease pathogenesis and treatment.