Diagnosis and Treatment of Normotensive Hydrocephalus

D.A. Mirsadykov

(Polenov Research Neurosurgical Institute, Saint Petersburg)

The goal of the study was to improve diagnosis and treatment of normotensive hydrocephalus (NTH).

The study was based on the results of complex examination and treatment of 289 cases with NTH, aged 1 month-75 years (223 children and 66 adults). The most frequent cause of NTH in children was congenital and perinatal pathology. Hydrocephalus in adults was of traumatic or vascular etiology in the majority of cases. NTH was usually accompanied by symptomatic epilepsy, Arnold-Chiari malformation, myelomeningocele, cystic lesions of the brain.

The patients with NTH were subdivided into 3 groups. They were as follows: NTH without accompanying pathology 99 cases (76 children, 23 adults); NTH against a background of CNS pathology 111 cases (82, 29); NTH against a background of seizures 79 cases (65, 14).

Calculation of Evans index showed, that the overwhelming majority of cases had the first degree of ventriculomegaly. As for cases with hypertensive hydrocephalus, more than a half of them had ventriculomegaly of the second and third degrees. Interventions were performed in 113 out of 289 cases with NTH. Their number was equal to 133 (72 liquor-shunting operations (LSO) and 61 operations on CNS structures).

Surgical treatment of children with NTH without accompanying pathology was indicated in 10.5% of cases and only in presence of Hakim-Adams triad (1), incomplete Hakin-Adams triad (2) and maximum neurological deficit (3). In minimum neurological deficit decision making in favor of surgical treatment was based on PET and/or SPECT data. Surgical treatment resulted in improvement of a state in all children of this group. As for adults with NTH, surgical treatment was indicated more often in comparison with children (39.1% of cases) and only in presence of Hakim-Adams triad (1) or incomplete Hakim-Adams triad (2).

Indications for surgical treatment were present in all 4 subgroups of children with NTH and accompanying CNS abnormalities. It was carried out in 43 cases (52.4%). A state improvement was watched in the majority of cases. Indications for surgical treatment of adults with NTH, accompanied by CNS abnormalities, were present in all subgroups under discussion. Almost a half of patients underwent liquor-shunting operations. Surgical treatment led to improvement of a state in the majority of cases. Indications for surgical treatment were present in all subgroups of children with NTH and seizures. A postoperative period was characterized by improvement of a state in all patients. Improvement manifested itself in reduction of seizure episodes. Complete or incomplete Hakim-Adams triad, as well as maximum neurological deficit were indication for surgical treatment in cases with NTH and seizures. Liquor-shunting or combined operations were performed. There was no improvement in 1 patient. The analysis of results demonstrated, that a choice of a method and tactics of treatment in NTH with accompanying symptomatic epilepsy was greatly conditioned by peculiarities of a clinical course; a character of bioelectric activity, studied with EEG; interoscopy data and results of examination with use of isotopes (PET and/or SPECT).

Conclusions

1. Symptomatic epilepsy, Arnold-Chiari malformation, myelomeningocele, cerebral hernias, arachnoid cysts, craniostenosis, corpus callosum dysgenesis, Kimmerly abnormality are the most frequent accompanying diseases of NTH. This intercurrent pathology is often a cause of a leading clinical syndrome.

2. A clinical course of NTH in children is remittent, whereas it is progradiently progressive in hypertensive hydrocephalus. A course, characterized by transformation of NTH into hypotensive hydrocephalus, demanding liquor shunting, is most typical of children and young people. Decompensation of clinical manifestations in children with NTH is connected with latent hypertension.

3. It is expedient to carry out individual selection of a shunt, based on multimodality examination, which should include CT and/or MRI, PET and/or SPECT and an infusion liquor test. Use of liquor-shunting operations allows to reduce clinical manifestation of the disease to this or that extent in the majority of patients. After them a state of almost all cases with NTH is shunt-dependent.

4. If NTH is accompanied by some pathology of the nervous system, it is necessary to estimate indications and to apply multi-stage surgical correction. Priority of stages of surgical treatment is determined for each individual case.