Current concepts on the pathophysiology of idiopathic chronic adult hydrocephalus: Are we facing another neurodegenerative disease?

INTRODUCTION

Since its description five decades ago, the pathophysiology of idiopathic chronic adult hydrocephalus (iCAH) has been traditionally related to the effect that ventricular dilatation exerts on the structures surrounding the ventricular system. However, altered cerebral blood flow, especially a reduction in the CSF turnover rate, are starting to be considered the main pathophysiological elements of this disease.

DEVELOPMENT

Compression of the pyramidal tract, the frontostriatal and frontoreticular circuits, and the paraventricular fibres of the superior longitudinal fasciculus have all been reported in iCAH. At the level of the corpus callosum, gliosis replaces a number of commissural tracts. Cerebral blood flow is also altered, showing a periventricular watershed region limited by the subependymal arteries and the perforating branches of the major arteries of the anterior cerebral circulation. The CSF turnover rate is decreased by 75%, leading to the reduced clearance of neurotoxins and the interruption of neuroendocrine and paracrine signalling in the CSF.

CONCLUSIONS

iCAH presents as a complex nosological entity, in which the effects of subcortical microangiopathy and reduced CSF turnover play a key role. According to its pathophysiology, it is simpler to think of iCAH more as a neurodegenerative disease, such as Alzheimer disease or Binswanger disease than as the classical concept of hydrocephalus.

[Analysis of subdural intracraneal empyemas in a third level hospital]

INTRODUCTION

Intracranial subdural empyema (ISE) is an infrequent infectious disorder of diverse etiology and difficult to diagnose because of its non-specific clinical features.

PATIENTS AND METHODS

Retrospective study of patients diagnosed of ISE in a third-level university hospital in a 15-year period.

RESULTS

Five men were included (mean age: 39.3 years). The most frequent primary source of infection was otic and sinusal (60%). The initial clinical manifestations were fever, headache, alteration of consciousness, and neurological focal symptoms. The mean time elapsed between onset of symptoms and diagnosis was 3.6 days. Diagnosis was performed by computed tomography in all patients. ISE was localized in the left hemisphere in 60% of cases mainly affecting the parietal lobe (80%). Anaerobic and streptococci germs were the most frequently isolated microorganisms. Therapy was based on antibiotics and surgical drainage in 100% of the cases. The surgical procedure used in the evacuation of empyema was craniotomy in all the patients. The mean time elapsed between diagnosis and surgery was 8.4 days. The mean Intensive Care Unit stay was 12.8 days, whereas the overall mean in-hospital stay was 45.2 days. Mortality was 40%.

CONCLUSION

ISE, although infrequent, displays a high morbimortality that can be reduced with an early therapeutic approach which may include the surgical evacuation in all the cases.

[Current controversies in pathophysiology of cervical spondylotic myelopathy]

Cervical spondylotic myelopathy is the most severe consequence of degenerative disease of cervical spine. In this article we perform a bibliographic review, addressing current controversies in its pathophysiology. Present work lines of most groups dedicated to the study of this condition are focused on improving surgical techniques designed for the treatment of this disease. Pathophysiological studies are scarce, and most of our pathophysiological knowledge of cervical spondylotic myelopathy is based in works done in 60s and 70s. Literature of the last decade lacks neurochemichal studies parallel to those existing for acute spinal injury. In the same way, only three prospective clinical trials comparing conservative and surgical treatment have been done, and none of them has demonstrated clear superiority of surgery. Given the high prevalence of this disease, the need for deep knowledge of its pathophysiologic, neurochemichal and molecular basis, and the optimization of surgical treatment is justified. This probably implies the need for prospective randomized trials to determine which patients are going to benefit from surgery.