Revisiting secondary normal pressure hydrocephalus: does it exist? A review

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>There are several etiologies that can lead to the development of secondary normal pressure hydrocephalus (sNPH). The aim of this study was to evaluate the etiology, diagnosis, treatment, and outcome in patients with sNPH and to highlight important differences between the separate etiologies.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>A comprehensive review of the literature was performed to identify studies conducted between 1965 and 2015 that included data regarding the etiology, treatment, diagnosis, and outcome in patients with sNPH. Sixty-four studies with a total of 1309 patients were included. The inclusion criteria of this study were articles that were written in English, included more than 2 patients with the diagnosis of sNPH, and contained data regarding the etiology, diagnosis, treatment, or outcome of NPH. The most common assessment of clinical improvement was based on the Stein and Langfitt grading scale or equivalent improvement on other alternative ordinal grading scales.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>The main etiologies of sNPH were subarachnoid hemorrhage (SAH) in 46.5%, head trauma in 29%, intracranial malignancies in 6.2%, meningoencephalitis in 5%, and cerebrovascular disease in 4.5% of patients. In 71.9% of patients the sNPH was treated with ventriculoperitoneal shunt placement, and 24.4% had placement of a ventriculoatrial shunt. Clinical improvement after shunt placement was reported in 74.4% and excellent clinical improvement in 58% of patients with sNPH. The mean follow-up period after shunt placement was 13 months. Improvement was seen in 84.2% of patients with SAH, 83% of patients with head trauma, 86.4% of patients with brain tumors, 75% of patients with meningoencephalitis, and 64.7% of patients with NPH secondary to stroke.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>Secondary NPH encompasses a diverse group of clinical manifestations associated with a subset of patients with acquired hydrocephalus. The most common etiologies of sNPH include SAH and traumatic brain injury. Secondary NPH does indeed exist, and should be differentiated from idiopathic NPH based on outcome and on clinical, pathophysiological, and epidemiological characteristics, but should not be considered as a separate entity.</jats:p></jats:sec>

A Dramatic Improvement by Ventriculoperitoneal Shunt Surgery in a Patient With Secondary Normal Pressure Hydrocephalus

“…The better response to shunt surgery in sNPH (in comparison to iNPH) has also been emphasized in other studies [3]. The diagnosis of sNPH is based on a combination of clinical history, physical examination, and imaging studies [2]. In our patient, the clinical presentation was characterized by the classic triad of dementia, gait disturbance, and urinary incontinence.…”

“…Approximately, 50% of the normal pressure hydrocephalus (NPH) cases occur in association with prior events that cause the development of this syndrome [1]. In the recent crucial report by Daou et al, it was concluded that sNPH should be differentiated from idiopathic NPH (iNPH) based on outcome and on clinical, pathophysiological, and epidemiological characteristics, but should not be considered as a separate entity [2]. The better response to shunt surgery in sNPH (in comparison to iNPH) has also been emphasized in other studies [3].…”

Dopaminergic Degeneration and Small Vessel Disease in Patients with Normal Pressure Hydrocephalus Who Underwent Shunt Surgery

“…As the main pathophysiology of patients' symptoms is derived from excessive accumulation of CSF in cerebral ventricular systems, clinical improvement of iNPH can be achieved mainly by shunt implantation surgery aimed at diverting the flow and absorption of CSF. This results in ameliorations of up to 50% and 80% in the symptoms of NPH [38]. To select candidates for shunt surgery, prognostic information is gathered from clinical examination, neuroimaging, and CSF testing [3].…”

Normal pressure hydrocephalus secondary to Lyme disease, a case report and review of seven reported cases

“…Since 2000 [ 5 ] the term secondary NPH in contrast to idiopathic NPH has been used in the literature, and while the definition of iNPH previously was “just” the lack of an explanation [ 6 ], later studies [ 7 , 8 ] have shown, that both the pathophysiology, the type of expansion of the ventricular system [ 7 ], the epidemiological characteristics [ 9 ] and the prognosis after treatment [ 9 ] differs between iNPH and sNPH.…”