TY - JOUR
T1 - Low pressure hydrocephalus and ventriculomegaly
T2 - Hysteresis, non-linear dynamics, and the benefits of CSF diversion
AU - Lesniak, M. S.
AU - Clatterbuck, R. E.
AU - Rigamonti, D.
AU - Williams, M. A.
PY - 2002/12
Y1 - 2002/12
N2 - Low pressure hydrocephalus (LPH) is a rare clinical condition. We report our experience with 10 patients treated at the Johns Hopkins Hospital. We reviewed the records of 10 patients (five men, five women; mean age 43 years) treated between 1996 and 2000. All underwent intracranial pressure (ICP) monitoring and subatmospheric cerebrospinal fluid (CSF) drainage with an intraventricular or lumbar catheter. All patients developed ventriculomegaly: five following aneurysmal subarachnoid haemorrhage; one after meningitis; one after intraventricular haemorrhage. Three patients presented with chronic aqueductal stenosis. Ventriculomegaly was clinically detected on average 12 days after presentation. Mean ICP was 4.8 mmHg (range 0-10). All patients improved only in the setting of negative pressure CSF drainage, and were subsequently treated with low pressure ventriculo- or lumboperitoneal shunts. At 1 year, eight patients (80%) showed good recovery to minimal disability; seven patients (70%) had resolving ventriculomegaly. The mechanism of low pressure hydrocephalus remains unclear. In our cohort, different aetiologies were responsible for the change in compliance/elastance of the brain parenchyma and subsequent development of ventriculomegaly. We propose that while ventriculomegaly (and therefore neuronal dysfunction) can be initiated in the setting of high ICP, the maintenance of ventriculomegaly at normal or low ICP is a physiological example of hysteresis. This behaviour, which has been characterized by the chaos theory of non-linear dynamics as a Hopf bifurcation, explains how a system can exhibit two different states (ventricular size) at a single parameter value (ICP). Most importantly, it helps to explain how lowering ICP in the setting of LPH can resolve ventriculomegaly and its neurologic sequelae.
AB - Low pressure hydrocephalus (LPH) is a rare clinical condition. We report our experience with 10 patients treated at the Johns Hopkins Hospital. We reviewed the records of 10 patients (five men, five women; mean age 43 years) treated between 1996 and 2000. All underwent intracranial pressure (ICP) monitoring and subatmospheric cerebrospinal fluid (CSF) drainage with an intraventricular or lumbar catheter. All patients developed ventriculomegaly: five following aneurysmal subarachnoid haemorrhage; one after meningitis; one after intraventricular haemorrhage. Three patients presented with chronic aqueductal stenosis. Ventriculomegaly was clinically detected on average 12 days after presentation. Mean ICP was 4.8 mmHg (range 0-10). All patients improved only in the setting of negative pressure CSF drainage, and were subsequently treated with low pressure ventriculo- or lumboperitoneal shunts. At 1 year, eight patients (80%) showed good recovery to minimal disability; seven patients (70%) had resolving ventriculomegaly. The mechanism of low pressure hydrocephalus remains unclear. In our cohort, different aetiologies were responsible for the change in compliance/elastance of the brain parenchyma and subsequent development of ventriculomegaly. We propose that while ventriculomegaly (and therefore neuronal dysfunction) can be initiated in the setting of high ICP, the maintenance of ventriculomegaly at normal or low ICP is a physiological example of hysteresis. This behaviour, which has been characterized by the chaos theory of non-linear dynamics as a Hopf bifurcation, explains how a system can exhibit two different states (ventricular size) at a single parameter value (ICP). Most importantly, it helps to explain how lowering ICP in the setting of LPH can resolve ventriculomegaly and its neurologic sequelae.
KW - Cerebrospinal fluid shunts
KW - Hysteresis
KW - Low pressure hydrocephalus
KW - Non-linear dynamics
KW - Subarachnoid haemorrhage
KW - Ventriculomegaly
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U2 - 10.1080/02688690209168360
DO - 10.1080/02688690209168360
M3 - Article
C2 - 12617236
AN - SCOPUS:0036935580
SN - 0268-8697
VL - 16
SP - 555
EP - 561
JO - British journal of neurosurgery
JF - British journal of neurosurgery
IS - 6
ER -