Follow up lumbar puncture - days after diagnosis, reduces death from cryptococcal meningitis in AIDS
August 18 2014
High opening pressure at lumbar puncture (LP) (spinal tap) is recognised as a poor prognostic feature of cryptococcal meningitis. For these patients repeated LP is advocated, including the use of lumbar drains or ventricular shunts in some cases.
In a provocative paper from Uganda, Rolfes and colleagues found that at least one ‘therapeutic’ LP for high opening pressure or a change in clinical status reduced death significantly, regardless of the actual opening pressure. 75 (30%) individuals had at least one therapeutic LP and only 5 deaths (7%) occurred in this group compared with 31 deaths (18%) occurred among 173 individuals without a therapeutic LP. The adjusted relative risk of mortality was 0.31 (95% confidence interval: 0.12-0.82). Those individuals receiving therapeutic LPs were in a poorer prognostic group, having higher CSF opening pressures, higher CSF fungal burdens, and were more likely to have altered mental status at baseline than those with no therapeutic LPs.
The reason for improvement after LP is not clear. Once an LP has been done, a small hole in the dura in the lumbar sac remains and CSF will continue to leak out. It is possible that additional LPs provide a means of clearing a considerable number of cryptococcal cells, by allowing them to be taken up into lymph channels in the lumbar area, rather than sticking around the brain. Alternatively lowering of pressure into much lower levels than have been considered dangerous could be beneficial. Alternative measures to lower intracranial pressure such as corticosteroids and acetazolamide are ineffective, although intravenous mannitol multiple times daily for several days is thought to be useful.
While these data are not definitive, second and third LPs early after diagnosis may improve outcome. Definitive guidance is important and will require additional study.