Normal pressure hydrocephalus

Your brain has built-in, fluid-filled spaces called ventricles. Normally, spinal fluid flows smoothly through these spaces, cushioning your brain before draining away. Normal pressure hydrocephalus (NPH) happens when this fluid fails to drain properly, causing the spaces to slowly expand like a balloon and press against the surrounding brain tissue. Even though extra fluid is trapped, the overall pressure inside your head stays normal or near-normal, which is how the condition got its name.

As these fluid spaces expand, they stretch and squeeze the nearby nerves that control your movement, thinking, and bladder. Doctors classify NPH into two types based on how it starts:

• Idiopathic NPH: the most common type, in which no clear underlying cause can be identified, usually in adults over age 60.

• Secondary NPH: this type happens after a specific event damages the brain's natural drainage system, such as a past head injury, brain bleeding, meningitis, or brain surgery.

NPH is characterised by the classic triad of symptoms, though not all three need to be present simultaneously. Symptoms develop gradually over months to years:

Gait disturbance is typically the earliest and most prominent symptom:

• A shuffling, broad-based, magnetic gait, as if the feet are glued to the floor

• Short steps with reduced foot clearance

• Difficulty initiating walking, turning, or navigating stairs

• Frequent falls from instability

• The gait in NPH resembles Parkinson's disease but typically does not improve with levodopa treatment

Cognitive impairment:

• Slowed thinking and reduced processing speed

• Memory difficulties, particularly for recent events

• Reduced attention and concentration

• Apathy and reduced initiative

• Executive dysfunction affecting planning and organisation

• The pattern resembles subcortical dementia rather than the memory-predominant pattern of Alzheimer's disease

Urinary incontinence:

• Urgency incontinence, a sudden compelling urge to urinate that cannot be deferred

• Frequency of urination

• In more advanced cases, complete loss of bladder control

The exact mechanisms behind normal pressure hydrocephalus are not fully understood. NPH is thought to involve impaired circulation or absorption of cerebrospinal fluid (CSF), leading to enlargement of the brain's ventricles. Contributing factors include:

• Age: the most common cause is simply aging. As we get older, the tiny channels that naturally filter and drain spinal fluid out of the brain become stiff and less efficient, causing fluid to slowly back up.

• Previous brain bleeding or injury: subarachnoid haemorrhage, intracranial bleeding, or traumatic brain injury can interfere with normal CSF circulation or absorption.

• Brain infections: meningitis and other infections affecting the brain or its surrounding membranes can disrupt CSF absorption.

• Previous brain surgery: surgery involving the brain or its surrounding structures can occasionally alter normal CSF circulation or absorption.

• Other neurological conditions: conditions affecting CSF circulation or absorption can occasionally contribute to secondary NPH.

Normal pressure hydrocephalus is detected primarily through brain MRI, with blood tests identifying coexisting conditions and excluding metabolic causes of similar symptoms.

Brain MRI Elfcare’s full-body MRI an show enlargement of the brain's ventricles and other structural features that may be seen in NPH. It looks for telltale signs of fluid backup, such as abnormally enlarged fluid spaces that are squeezing nearby brain tissue. This allows doctors to tell NPH apart from normal aging or brain shrinkage, which is vital since NPH is highly treatable.

Blood tests cannot detect NPH directly but identify coexisting conditions and metabolic causes of similar symptoms. Relevant markers in Elfcare's panel include:

• TSH, Free T3, and Free T4 hypothyroidism causes gait disturbance, cognitive slowing, and urinary symptoms closely resembling the NPH triad and must always be excluded

• Vitamin B12 and folate deficiency causes cognitive impairment and gait ataxia that can overlap significantly with NPH presentation

• HbA1c and glucosediabetes causes peripheral neuropathy affecting gait and cognitive impairment from cerebrovascular disease

• Creatinine and eGFR assesses kidney function and identify kidney disease that may contribute to cognitive or general health problems

Why early detection matters

Normal pressure hydrocephalus is one of the most treatable causes of dementia-like symptoms in older adults, yet it is consistently underdiagnosed, with many patients living for years with a diagnosis of Parkinson's disease or Alzheimer's disease when NPH is the actual or contributing cause. The response to treatment, specifically CSF drainage through a ventriculoperitoneal shunt, is best when symptoms are identified at an early stage before irreversible damage to compressed white matter pathways has occurred. Gait symptoms often show the clearest improvement after shunt treatment, although the degree and timing of improvement vary between individuals. Identifying NPH through brain MRI before cognitive impairment has become severe and while gait disturbance is still responsive to treatment represents one of the most impactful outcomes a full body health check can produce for an older adult.

How Elfcare can help

Elfcare's full body MRI includes brain imaging that can show ventricular enlargement and other structural abnormalities that may warrant further assessment.

Our blood panel covers the key metabolic conditions causing overlapping symptoms, ensuring that reversible causes of cognitive and gait symptoms are identified alongside any structural findings on MRI.

If our MRI or blood tests identify findings consistent with NPH, we take care of further diagnostics or refer you to the appropriate specialist.