[Clinical characteristics and indications for shunting in patients with idiopathic normal pressure hydrocephalus with brain atrophy (atypical idiopathic normal pressure hydrocephalus)].
OBJECTIVE
To clarify clinical characteristics of atypical idiopathic normal pressure hydrocephalus (AINPH) and indications for shunt operations.


METHODS
Subjects examined in the present study included 65 patients who satisfied the following 4 diagnostic criteria of AINPH and underwent V.P shunt with Medos type shunt system; set pressure: epidural standard pressure x 13.6 - 20 mmH2O (omission of a figure in the first place). The diagnostic criteria were: 1) no apparent history of intra- or extra-cranial disease; 2) dementia was present as a main complaint; 3) the presence of moderate to severe cerebral atrophy and ventricular enlargement and PVL around the anterior horn on CT scans; 4) normal cerebrospinal pressure and filling of ventricles or subarachnoid space with contrast medium at 24 hours on cisternography. The patients were aged 49-83 with the mean age of 62.9 years; the ratio of male to female was 37:28. They were categorized as shunt-effective (group E: 36 cases) or non-shunt-effective (group NE: 29 cases), and the following parameters in both groups were compared: 1. clinical characteristics: 2. the presence or absence of pressure wave (PW) during preoperative continuous epidural pressure measurement (EDPM) 3. CSF outflow resistance (Ro) 4. preoperative serum alpha-1-antichymotrpsin (alpha-1-ACT) 5. cerebral arteriovenous difference of oxygen content (c-AVDO2) before and after surgery 6. mean cerebral blood flow (mCBF; 99mTc-HMPAO-SPECT) before and after surgery.


CONCLUSIONS
1. Group E had a shorter duration between symptom onset and hospital visit (within 16 months and showed hyporoluntary and hyporeactivity as their main complaints associated with gait disturbance; the time course of symptoms was classified as suddenly progressing and fluctuating in many cases. Group NE had a relatively longer duration between symptom onset and hospital visit and showed activeness, wandering, nervousness and quick temper as their main complaints; the time course of symptoms was classified as progressing in many cases. 2. PW-positive cases were all included in group E. but some PW-negative cases were also observed in group E. 3. Ro was significantly higher in group E (p < 0.01), and cases with a Ro value over 20 mmHg/ml/min. were all included in group E. 4. alpha-1-ACT was significantly lower in group E (p < 0.05), and cases with an alpha-1-ACT value over 55 mg/dl were all included in group NE. 5. Although preoperative c-AVDO2 was significantly higher in group E (p < 0.05), cases with a c-AVDO2 value over 8.5 ml% were all included in group NE. c-AVDO2 values were within 5-8.5 ml% in all cases of group E. 6. mCBF significantly increased after surgery in group E (p < 0.001). 7. It was confirmed that cerebral atrophy in group E on AINPH is caused by a cerebral circulation disturbance defined as a cerebral blood flow of penumbra or more due to cerebral arteriosclerosis, etc. 8. A flowchart of indications for shunt surgery for AINPH was prepared based on the results of the present study.
Takeuchi
T
T
Department of Neurosurgery, Higashimatsuyama Municipal Hospital, Saitama, Japan.
Kasahara
E
E
Iwasaki
M
M
D000368:Aged; D000369:Aged, 80 and over; D001284:Atrophy / Q000150:complications / Q000601:surgery; D001921:Brain / Q000473:pathology*; D015170:Cerebrospinal Fluid Pressure; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D016896:Treatment Outcome; D017287:Ventriculoperitoneal Shunt; D000515:alpha 1-Antitrypsin / Q000032:analysis
D000515:alpha 1-Antitrypsin