Normal Pressure Hydrocephalus: Clinical Symptoms
Normal pressure hydrocephalus presents with a classic triad of gait disturbance, cognitive impairment, and urinary incontinence, with gait abnormalities typically appearing first and serving as the cardinal diagnostic feature. 1, 2, 3
Primary Symptom Triad
Gait Disturbance (The Cardinal Sign)
- The hypokinetic gait disorder is the most characteristic feature, occurring in approximately 70% of NPH patients and often the presenting symptom 2
- The feet appear "glued to the floor" or exhibit a "magnetic" quality, representing the pathognomonic sign of NPH 2, 4
- Gait abnormalities include shuffling, bradykinesia, unsteady balance, and postural instability 5, 4
- This symptom typically develops early in the disease course, before cognitive or urinary symptoms become prominent 1, 3
Cognitive Impairment
- Cognitive decline develops later in the disease progression and manifests with frontal lobe dysfunction patterns 3
- Specific deficits include psychomotor slowing, impaired attention, working memory deficits, reduced verbal fluency, and executive function impairment 3
- Memory lapses occur as part of the cognitive syndrome 3
- Mental deterioration may be mild initially but progresses without treatment 6, 7
Urinary Incontinence
- Urinary symptoms include urgency, frequency, nocturia, and frank incontinence 1, 8, 4
- Bladder dysfunction is part of the classic triad but may not be present in all cases 8, 5
- Some patients may also develop fecal incontinence, though this is less common 5
Clinical Presentation Patterns
Temporal Evolution
- Patients typically present late in the disease course due to the slow, gradual onset of symptoms 1
- The triad may be incomplete or atypical, with not all three symptoms present simultaneously 7
- Gait alterations occur early, while cognitive impairment manifests later in the disease trajectory 1, 3
Diagnostic Challenges
- Approximately 80% of NPH cases remain unrecognized and untreated, largely due to difficulty distinguishing NPH from other neurodegenerative disorders 6
- Three-quarters of patients with NPH severe enough to require treatment also have comorbid neurodegenerative disease, particularly Alzheimer's disease (affecting 20-57% of NPH patients) 3, 9
- The clinical presentation can mimic several other neurodegenerative conditions, making diagnosis challenging 5, 7
Key Clinical Pitfalls
The incomplete or atypical presentation of the triad is a major diagnostic pitfall—do not exclude NPH if only one or two symptoms are present, particularly if gait disturbance is prominent. 7
- The prevalence of NPH is estimated at 3.7% in patients over 65 years of age, making it a significant but underdiagnosed cause of potentially reversible dementia 1
- Without treatment, the spontaneous course of NPH leads to nursing care dependence in the vast majority of patients 6
- Early recognition and treatment are critical, as properly selected patients have an 80-90% chance of responding to shunt surgery with improvement in all symptoms 2, 6