[Nosocomial meningitis in the adult]

Cerebrospinal fluid (CSF) has anti-infectious defense abilities similar to those of the serum of a neutropenic patient. A septic inoculation as in case of nosocomial meningitis (NM), results rapidly in microbial proliferation with major alterations to the blood brain barrier, cerebral oedema and loss of autoregulation of the cerebral blood flow. Arterial hypotension during NM may induce focal or global cerebral ischaemia. The incidence of NM is increasing, staphylococci and Gram negative bacilli being the most frequent pathological agents. Clinical symptoms are not specific in this postoperative and post-traumatic context. In this context, the analysis of pleocytosis and the increased protein content of CSF is disturbing. Numerous clinical conditions may cause NM. Among them, NM from spinal puncture is an important issue for anaesthetists, while combined epidural and spinal anaesthesia carry the highest risks. Cutaneous contamination plays a major role. Half of the post-operative infections after neurosurgery are due to NM, and CSF leakage, iterative operations and surgery in contaminated conditions are the main risk factors. Antibioprophylaxis for postoperative NM is validated for clean and clean-contaminated surgery. Some consider that only procedures of more than two hours require this prophylaxis. Prophylaxis is targeted on staphylococci. Other preventive measures (drainage of less than 24 h, head shaving and prevention of CSF leakage) are of major importance. Antibiotherapy should be guided by the same considerations as for community acquired meningitis, associated with specific issues in the surgical context (presence of foreign material and CSF blockage).