[Mixed connective tissue disease revealed by chronic lymphocytic meningitis in an infant]

Mixed connective tissue disease (MTCD) is a systemic inflammatory disorder individualised by Sharp et al. in 1972. This entity is rare in children.

We report an exceptional case of MTCD revealed by lymphocytic meningitis in a two-month-and-a-half-old infant. The disease was diagnosed at the age of nine months when clinical symptomatology was completed by common signs of the illness (Raynaud's phenomenon, swollen hands), systemic lupus erythematosus-like symptoms (lymphadenopathy, squamous erythema of the limbs, hepato-splenomegaly, pleuritis and ascites) and polymyositis-like findings (muscle weakness with increased serum levels of myogenic enzymes). Laboratory investigations showed an important inflammatory syndrome and the presence of speckled anti-nuclear and anti-U(1)RNP antibodies. Specific antibodies of the other connective tissue diseases were also positive (anti-DNA, anti-Sm, anti-SSA and SSB, anti-Scl 70 and JO1) pleading for the mixed feature of the illness. The follow-up after corticosteroid treatment was marked by clinical and biological improvement. But after five months, the patient died following a severe infectious complication.

Chronic lymphocytic meningitis can be part of Sharp's syndrome even in infants. However, the diagnosis relies on the evidence of characteristic clinical and biological abnormalities of MTCD.