Intracerebral microdialysis and CSF hydrodynamics in idiopathic adult hydrocephalus syndrome.
BACKGROUND
In idiopathic adult hydrocephalus syndrome (IAHS), a pathophysiological model of "chronic ischaemia" caused by an arteriosclerotic process in association with a CSF hydrodynamic disturbance has been proposed.


OBJECTIVE
To investigate whether CSF hydrodynamic manipulation has an impact on biochemical markers related to ischaemia, brain tissue oxygen tension (PtiO(2)), and intracranial pressure.


METHODS
A microdialysis catheter, a PtiO(2) probe, and an intracerebral pressure catheter were inserted into the periventricular white matter 0-7 mm from the right frontal horn in 10 patients with IAHS. A subcutaneous microdialysis probe was used as reference. Intracranial pressure and intracerebral PtiO(2) were recorded continuously. Samples were collected for analysis between 2 and 4 pm on day 1 (baseline) and at the same time on day 2, two to four hours after a lumbar CSF hydrodynamic manipulation. The concentrations of glucose, lactate, pyruvate, and glutamate on day 1 and 2 were compared.


RESULTS
After CSF drainage, there was a significant rise in the intracerebral concentration of lactate and pyruvate. The lactate to pyruvate ratio was increased and remained unchanged after drainage. There was a trend towards a lowering of glucose and glutamate. Mean intracerebral PtiO(2) was higher on day 2 than on day 1 in six of eight patients.


CONCLUSIONS
There is increased glucose metabolism after CSF drainage, as expected in a situation of postischaemic recovery. These new invasive techniques are promising tools in the future study of the pathophysiological processes in IAHS.
Agren-Wilsson
A
A
Department of Clinical Neuroscience, Umeå University, S-901 85 Umeå, Sweden. aina.agren.wilsson@neuro.umu.se
Roslin
M
M
Eklund
A
A
Koskinen
L-O D
LO
Bergenheim
A T
AT
Malm
J
J
D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D001921:Brain / Q000503:physiopathology; D002545:Brain Ischemia / Q000150:complications / Q000503:physiopathology; D002555:Cerebrospinal Fluid / Q000502:physiology*; D002557:Cerebrospinal Fluid Shunts; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D006849:Hydrocephalus / Q000503:physiopathology* / Q000601:surgery; D002537:Intracranial Arteriosclerosis / Q000150:complications / Q000503:physiopathology; D007427:Intracranial Pressure / Q000502:physiology; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D019289:Pyruvic Acid / Q000378:metabolism
D001786:Blood Glucose; D019344:Lactic Acid; D018698:Glutamic Acid; D019289:Pyruvic Acid