VHOSPITAL.CLINIC · Differential Diagnosis
Alzheimer's Disease vs Normal Pressure Hydrocephalus
Clinical comparison — shared symptoms, key differences, distinguishing diagnostic tests, treatment pathways, and when to seek urgent evaluation.
Condition Overview
Condition A
Alzheimer's Disease
Alzheimer's disease is the most common cause of dementia — a progressive neurological disorder that destroys memory and other cognitive functions. It typically begins with mild memory loss and progresses to severe cognitive impairment.
Condition B
Normal Pressure Hydrocephalus
Normal pressure hydrocephalus presents with the classic triad of gait disturbance, urinary incontinence, and cognitive decline in older adults. It is caused by abnormal CSF accumulation and can be treated with ventricular shunting.
Shared Symptoms — Why They're Confused
Both conditions present with 3 overlapping symptoms, making clinical differentiation essential.
Key Clinical Differences
Alzheimer's Disease
- Insidious progressive memory impairment
- Language, visuospatial, and executive dysfunction
- No gait abnormality early
- MRI: hippocampal atrophy
Normal Pressure Hydrocephalus
- Classic triad: gait apraxia (magnetic gait), cognitive impairment, urinary incontinence
- Gait disturbance typically appears FIRST
- Ventriculomegaly disproportionate to cerebral atrophy on MRI
- Potentially reversible with CSF shunting
Distinguishing Diagnostic Tests
| Test | Alzheimer's Disease | Normal Pressure Hydrocephalus |
|---|---|---|
| MRI brain | Hippocampal and entorhinal cortex atrophy; no ventriculomegaly | Ventriculomegaly out of proportion to sulcal atrophy; periventricular lucencies |
| Gait assessment | Gait normal early; shuffling only in advanced stages | Magnetic gait (feet appear glued to floor) as early prominent feature |
| CSF large-volume tap test (30 ml) | No improvement in cognition or gait | Temporary improvement in gait and cognition — supports NPH diagnosis |
Treatment Approaches
Alzheimer's Disease
- •Acetylcholinesterase inhibitors (donepezil, rivastigmine)
- •Memantine for moderate-severe disease
- •Non-pharmacological: cognitive stimulation, caregiver support
Normal Pressure Hydrocephalus
- •Ventriculoperitoneal (VP) shunt — potentially curative if identified early
- •Repeated lumbar punctures as temporising measure
When Doctors Consider Each Diagnosis
🔵 Consider Alzheimer's Disease when:
- →Memory-first decline, hippocampal atrophy, no gait disturbance early
🟢 Consider Normal Pressure Hydrocephalus when:
- →Gait-first triad, ventriculomegaly disproportionate to atrophy, tap test improvement
Explore Each Condition in Detail
Related Clinical Pages
Alzheimer's Disease
Medical References
Content on this page is informed by evidence-based clinical sources including:
- World Health Organization (WHO)Global health guidance and disease classification
- National Health Service (NHS)UK clinical guidelines and patient information
- National Institute for Health and Care Excellence (NICE)Evidence-based clinical practice guidelines
- Centers for Disease Control and Prevention (CDC)US public health data and clinical recommendations
- PubMed – NCBIPeer-reviewed biomedical literature and clinical studies
- Cochrane LibrarySystematic reviews and meta-analyses in evidence-based medicine
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