What are the diagnostic criteria for hydrocephalus in adults?

From the Guidelines

Hydrocephalus in adults is diagnosed based on a combination of clinical symptoms, imaging findings, and sometimes cerebrospinal fluid (CSF) dynamics testing, with the most recent and highest quality study suggesting that MRI head without IV contrast or CT head without IV contrast is usually appropriate for the initial imaging 1. The key diagnostic criteria include clinical symptoms such as headache, cognitive decline, gait disturbance, and urinary incontinence, along with radiographic evidence of ventricular enlargement on brain imaging (CT or MRI).

• The Evans' index, which measures the ratio of the maximum width of the frontal horns to the maximum inner skull diameter, should exceed 0.3.
• Additional criteria include periventricular edema, thinning of the corpus callosum, and enlargement of temporal horns.
• For normal pressure hydrocephalus (NPH), the classic triad of gait disturbance, cognitive impairment, and urinary incontinence is particularly important, though not all symptoms need to be present.
• CSF tap tests or lumbar drainage trials showing clinical improvement after CSF removal strongly support the diagnosis.
• Intracranial pressure monitoring may be necessary in some cases, with normal or intermittently elevated pressures typically seen in NPH. These criteria help differentiate hydrocephalus from other conditions causing ventricular enlargement, such as brain atrophy, and guide treatment decisions regarding shunt placement or endoscopic third ventriculostomy, as suggested by studies 1. In terms of management, early diagnosis and initiation of therapy is crucial to prevent death and many of the complications that ongoing meningeal inflammation produces, with medical therapy and repeated lumbar punctures as initial management, and early MRI of the brain and neurosurgical consultation recommended 1.

From the Research

Hydrocephalus Criteria in Adults

The diagnosis and treatment of hydrocephalus in adults involve various criteria and considerations. Some key points to consider include:

• The clinical spectrum of hydrocephalus in adults comprises more than idiopathic normal pressure hydrocephalus (iNPH) or acquired hydrocephalus, with 43% of patients having childhood onset 2
• The Adult Hydrocephalus Clinical Research Network (AHCRN) registry categorizes adult hydrocephalus into four groups: transition, unrecognized congenital, acquired, and suspected iNPH 2
• Patients with suspected iNPH tend to have the poorest performance in cognitive evaluations and the lowest gait velocity 2
• A comprehensive adult hydrocephalus clinic model is recommended to advance our understanding of this diverse patient population and provide better standard of patient care 3

Diagnostic Criteria

Diagnostic criteria for hydrocephalus in adults may include:

• Imaging studies such as magnetic resonance imaging (MRI) or computed tomography (CT) scans to evaluate ventricular size and cerebrospinal fluid (CSF) flow 4, 5
• Clinical evaluation of symptoms such as gait disturbance, dementia, and urinary incontinence 6, 2
• Neuropsychology screening and examination findings to assess cognitive function and impairment 2

Treatment Criteria

Treatment criteria for hydrocephalus in adults may include:

• Ventriculoperitoneal shunting for patients with iNPH or other forms of hydrocephalus 6, 5
• External lumbar drainage (ELD) as a diagnostic test to predict response to shunting 6
• Consideration of comorbidities and etiologies of hydrocephalus that may affect treatment outcomes 2