Vascular factors in suspected normal pressure hydrocephalus

Abstract

Objective: We examined clinical and imaging findings of suspected idiopathic normal pressure hydrocephalus (iNPH) in relation to vascular risk factors and white matter lesions (WMLs), using a nested case-control design in a representative, population-based sample.Methods: From a population-based sample, 1,235 persons aged 70 years or older were examined with CT of the brain between 1986 and 2000. We identified 55 persons with hydrocephalic ventricular enlargement, i.e., radiologic findings consistent with iNPH. Among these, 26 had clinical signs that fulfilled international guideline criteria for probable iNPH. These cases were labeled suspected iNPH. Each case was matched to 5 controls from the same sample, based on age, sex, and study cohort. Data on risk factors were obtained from clinical examinations and the Swedish Hospital Discharge Register. History of hypertension, diabetes mellitus (DM), smoking, overweight, history of coronary artery disease, stroke/TIA, and WMLs on CT were examined. Risk factors associated with iNPH with a p value ,0.1 in x 2 tests were included in conditional logistic regression models. Idiopathic normal pressure hydrocephalus (iNPH) is probably more common than previously supposed. We have recently reported that 5.9% of persons older than 80 years have this disorder. 1 Treatment with shunt surgery improves symptoms in more than 80% of patients. 2 Despite this, iNPH is underdiagnosed and undertreated.1,3 Furthermore, little is known about the underlying disease mechanisms. It is important to learn more about risk factors for the disease in order to understand pathophysiologic mechanisms and suggest preventive measures. Vascular risk factors, such as hypertension, diabetes, and ischemic heart disease, have previously been associated with iNPH in hospital-based, case-control studies.4-9 Also, cerebral white matter lesions (WMLs), which are associated with small vessel disease and white matter ischemia, 10 are common in iNPH. 11,12 It has therefore been suggested that vascular mechanisms may be related to the development of iNPH. However, previous studies on risk factors have not been population-based. Furthermore, there are no previous epidemiologic investigations regarding WMLs in iNPH.

Cardiovascular risk factors in Chiari malformation and idiopathic intracranial hypertension

“…Thus, an association between cardiovascular disease and idiopathic normal pressure hydrocephalus (iNPH) was suggested (Casmiro et al., 1989; Earnest, Fahn, Karp, & Rowland, 1974; Edwards, Dombrowski, Luciano, & Pople, 2004; Graff‐Radford & Godersky, 1987; Jaraj et al., 2016; Koto, Rosenberg, Zingesser, Horoupian, & Katzman, 1977; Krauss et al., 1996). More recently, an increased age‐adjusted prevalence of cardiovascular disease and diabetes was reported in iNPH (Eide & Pripp, 2014) and noncommunicating hydrocephalus (ncHC) (Eide & Pripp, 2016) as compared to the general population (Table 6).…”

The role of diffusion tensor imaging and fractional anisotropy in the evaluation of patients with idiopathic normal pressure hydrocephalus: a literature review

“…13,39 The prevalence of this disease is age related, reaching 1%-5.9% among elderly individuals. 21,26 It remains one of the most controversial neuropathological entities both in regards to its diagnosis and its proper management. Characteristically, despite many recent advances in imaging methods, most NPH cases still remain idiopathic.…”

“…The exact underlying pathophysiological mechanism of this disorder has remained ill defined, and several theories supporting the combination of CSF circulation disturbances along with other cerebrovascular disorders have been proposed. 1,21,28,36,41,58 The diagnosis of NPH is based on a patient's clinical status, imaging findings, and the natural history of the disease. The imaging criteria for NPH are mainly ventricular enlargement (i.e., with an Evans index > 0.3), lack of any anatomical obstruction of the CSF circulation, enlarged temporal horns, and a corpus callosum (CC) angle of greater than 40° on brain CT or MRI scans.…”

Negative predictors of shunt surgery outcome in normal pressure hydrocephalus

“…8,9 In studies of vascular risk factors in patients with iNPH, the risk factors alone, such as diabetes or hypertension, do not seem to have a negative impact on outcome after shunting. 8,9 In studies of vascular risk factors in patients with iNPH, the risk factors alone, such as diabetes or hypertension, do not seem to have a negative impact on outcome after shunting.…”

“…4 Whether or not these outcome rates hold for older patients is not fully clarified; there are reports that high age could be a negative predictor for shunt surgery outcome, 5 while more recent reports propose that age alone should not exclude patients from surgery. 8,9 Earlier studies have reported that vascular comorbidities are associated with a less favourable outcome, [10][11][12] while more recent studies report that vascular disease is not a negative predictor. 8,9 Earlier studies have reported that vascular comorbidities are associated with a less favourable outcome, [10][11][12] while more recent studies report that vascular disease is not a negative predictor.…”