The development of a hydrocephalus as a typical complication after subarachnoid haemorrhage often requires implantation of a catheter for drainage of ventricular fluid. Because this is an open system it carries a risk of development of bacterial ventriculitis by contamination. This potentially life threatening or neurologically disabling disease can be diagnosed by microbiological tests on the CSF. However, microbiological examination is often not possible or shows pathological results only after a delay, probably because of antibiotic prophylaxis. Standard CSF indices are difficult to interpret, because subarachnoid haemorrhage leads to an irritation syndrome in the CSF, which can imitate infection.

Lysozyme is a basic polypeptide of 129 amino acids weighing 15 kDa, which is found in neutrophilic granulocytes or monocytes, and is released from cytoplasmic and azurophilic granules.1 It is capable of degrading bacterial proteoglycans.2 Lysozyme shows significantly higher concentrations in CSF in bacterial meningitis in comparison with abacterial meningitis, whereas in other diseases of the CNS much lower concentrations are found.3 4

We retrospectively documented the results from 146 patients who underwent external ventricular drainage after subarachnoid haemorrhage. As well as documenting the frequency and timing of infection, the medical notes were inspected for risk factors of infection.

In 64 …