Spaces in the brain, called ventricles, where excess cerebrospinal fluid can build up, causing NPH.
Idiopathic normal pressure hydrocephalus (INPH) is a treatable cause of gait disturbance, cognitive impairment, and urinary incontinence… Not all INPH patients exhibit clinical improvement after shunting, and it is challenging to identify patients who are more likely to benefit from shunting.
…discrepancies in treatment outcomes are the result of controversies in 3 distinct but interrelated domains: the underlying pathophysiology of INPH, the diagnosis of INPH, and the identification of likely shunt-responders.
…shunting is a safe and effective means of achieving meaningful clinical improvement in most patients with INPH.
…Normal pressure hydrocephalus (NPH) was first reported in 1965 as a triad of dementia, gait disturbance, and urinary incontinence, with associated ventricular dilatation and normal cerebrospinal fluid (CSF) pressure.
…NPH can be classified as idiopathic NPH (INPH) or secondary NPH (SNPH), the latter of which occurs most commonly after subarachnoid hemorrhage, trauma, or meningitis.
…surgical outcomes in INPH have been consistently less successful than those in SNPH.
…the reported rates of postoperative clinical improvement in INPH patients have varied from 24% to 96%.
…INPH typically occurs during the seventh decade of life.
…the prevalence is from 0.41% to 1.4% for persons aged 65 years or older.
…To date, no clear pathophysiological mechanism for INPH has been established.
…CSF diversion can improve INPH symptoms
…In their cohort of 93 patients with INPH, 65% of the immediate surgery group demonstrated an improvement in modified Rankin scale of at least 1 point at 3 months compared with 5% in the postponed treatment group.
Cerebrospinal fluid diversion is a procedure that is used to drain fluid from the brain and spinal cord. A shunt is placed in a ventricle of the brain and threaded under the skin to another part of the body, usually the abdomen. It is used to treat hydrocephalus and idiopathic intracranial hypertension.
…Diagnosing INPH is difficult, and the accepted gold standard for diagnosis is clinical improvement after shunt surgery. This implies a circular argument: shunt-responsive INPH (SR-INPH) is defined by a clinical response to CSF diversion.
…INPH is characterized by a slow, short-stepped shuffling with a slightly broad base, reduced step-height, and associated gait freezing. …It may also include postural instability and difficulty turning. These gait disturbances are consistent with subcortical deficits involving the basal ganglia and frontal periventricular pathways.
Although INPH was originally reported as a reversible dementia, dementia is in fact the triad symptom least likely to improve postoperatively. The typical cognitive deficits of INPH are “subcortical,” with psychomotor retardation, apathy, difficulty in executive functions, and impaired recall memory yet relatively preserved recognition memory.
Urinary symptoms in INPH usually begin as increased frequency and urgency, only developing into incontinence in later stages. Urinary symptoms respond well to shunting but only predict a functional improvement in 31% to 33% of patients.
Despite classically being a triad of symptoms, INPH can be diagnosed in the presence of gait disturbance and 1 other cardinal symptom. This is in light of findings revealing that the complete triad often represents prolonged symptom duration, more advanced disease, and a poorer prognosis.
…Neuroimaging evidence of hydrocephalus on computerized tomography (CT) or magnetic resonance imaging (MRI) is essential for the diagnosis of INPH.
…Much of the diagnostic uncertainty surrounding INPH relates to difficulties distinguishing INPH from other diagnoses common in the elderly. It is also important to note that multiple comorbidities are common in the elderly and can mimic INPH…
…Programmable valves have now been adopted, as they permit noninvasive pressure adjustments that can optimize clinical improvement and ameliorate drainage-related complications.
Overall, shunt-related complications occur in up to 38% of patients, 22% require additional surgery, and there is a 6% rate of permanent neurological deficit or death. Common complications include shunt malfunctions, infections, headaches, and drainage-related subdural hematomas or effusions.
A systematic review of 64 outcome studies demonstrated that 71% (range, 28%–100%) of patients with INPH had a positive outcome at 1 year after shunt insertion and that 65% (range, 31%–96%) demonstrated improvement beyond 3 years.
…the duration of postoperative follow-up necessary to adequately assess clinical status has not been established. For example, the Dutch NPH study restricted the follow-up period to 1 year, whereas other studies have demonstrated that some INPH patients still continue to improve at 24 months. On the other hand, studies that have followed patients for 3 years or more have consistently found declining rates of clinical improvement.However, long-term outcomes also undoubtedly are influenced by comorbidities, and vascular factors have been shown to be a main cause of mortality.
before proceedure
after proceedure
before proceedure
after proceedure
After 50 years of research, the diagnosis and treatment of INPH seems to have improved. …both the accurate diagnosis of INPH and the appropriate selection of shunt surgery candidates remain controversial issues. Those familiar with the condition can diagnose it, and most patients so diagnosed obtain meaningful clinical improvement.
