gms | German Medical Science

Objective: Radiological Disproportionate Enlarged Subarachnoid-Space Hydrocephalus (DESH) is almost pathognomonic for idiopathic normal pressure hydrocephalus (iNPH). Others have shown in a population-based study, that tight high convexity (THC) might precede asymptomatic ventriculomegaly in patient, that are more likely to develop iNPH (Iseki et al., 2009&2014). For pathophysiological investigative purposes we conducted the search the other way around.

Methods: All available digital imaging (CT or MRI) and clinical data of all iNPH patients that had contact with the neurological or neurosurgical clinic in 2014 or 2015 were reviewed. Time of onset of symptoms, time of first imaging (whatever the indication was) and birth date were recorded. The patients that had a discrepancy between time of symptomatic onset and time of first imaging were investigated in depth.

Results: In 2014 and 2015 151 patients had had contact with either the neurological or neurosurgical department. Of six patients imaging was available before onset of symptoms (mean 6.3 years, range 2.9 – 10.5 years). All six patients had undergone testing by lumbar drainage or puncture within 2 years after onset and were diagnosed with iNPH. In 5 of 6 patients the first symptom was gait imbalance. The MRI conducted 10.5 years before onset of symptoms showed normal ventricular width with THC. All other images within a shorter time to symptomatic onset showed classic DESH.

Conclusion: In accordance with scarcely available literature DESH is prominent at least several years before onset of iNPH-symptoms. Before that time THC develops first. Further studies are needed to put these findings into the pathophysiological perspective of the development of iNPH.