Cause 10. Normal Pressure Hydrocephalus (NPH): A Hidden Instigator
Lastly, a less recognized but significant cause of cerebellar ataxia is Normal Pressure Hydrocephalus (NPH). NPH is a condition characterized by an enlargement of the brain’s ventricles due to an accumulation of cerebrospinal fluid (CSF). Despite the term “normal pressure”, this fluid accumulation subtly and chronically exerts pressure on surrounding brain structures, including the cerebellum, disrupting their normal function and leading to ataxia.
A critical feature of NPH is its insidious onset. The condition typically affects older adults and presents a triad of symptoms: difficulty walking (gait disturbance), cognitive impairments (memory problems), and urinary incontinence. These symptoms, however, develop gradually and can easily be mistaken for normal aging or other neurodegenerative conditions like Parkinson’s or Alzheimer’s disease, leading to frequent underdiagnosis or misdiagnosis of NPH.
Gait disturbances are often the first symptom to appear in NPH and the most responsive to treatment. These disturbances can manifest as a broad-based, magnetic gait, where the patient’s feet appear as though they’re “stuck” to the floor. This can progress to more profound difficulties with balance and coordination, effectively mimicking cerebellar ataxia.
The pathophysiology underlying NPH is still not completely understood. The condition was initially believed to result from an imbalance in the production and absorption of CSF, leading to its accumulation. However, more recent theories suggest that NPH may result from decreased brain compliance or resistance to CSF outflow, suggesting a more complex interplay of factors.
The encouraging news is that, if diagnosed early, the symptoms of NPH, including the ataxia-like gait disturbance, can often be significantly improved with treatment. Therapeutic measures typically involve surgically inserting a shunt to drain the excess CSF and relieve the pressure on the brain. Alternatively, endoscopic third ventriculostomy, a procedure that creates an opening in the floor of the third ventricle to allow CSF to bypass the obstruction, can also be considered in certain cases. (10)
