Normal pressure hydrocephalus (NPH) is a poorly understood condition, which typically presents with the triad of gait disturbance, urinary incontinence and cognitive decline. Diagnosis of NPH is often challenging due to its varied presentation and overlap with other neurodegenerative diseases including multiple system atrophy (MSA).

A 68-year-old male developed rapidly progressive gait difficulty, urinary incontinence and memory impairment. Neurologic examination showed parkinsonism affecting the right side and impaired postural reflexes. Brain MRI showed enlargement of the ventricles and narrowing of the high convexity cerebrospinal fluid (CSF) spaces with relative dilated Sylvian fissure, the supporting features of NPH. 18F-fluorinated-N-3-fluoropropyl-2-b-carboxymethoxy-3-b-(4-iodophenyl) nortropane (¹⁸F-FP-CIT) PET showed decreased FP-CIT binding in the left posterior putamen and ¹⁸F-fluorodeoxyglucose PET showed decreased metabolism in the left basal ganglia, consistent with findings of MSA. CSF removal was performed and the symptoms were improved. The patient underwent ventriculo-peritoneal shunt and his gait and cognition improved.

NPH is a potentially treatable neurological disorder. Therefore, it is necessary to consider the possibility of accompanying NPH when hydrocephalus is present in other neurodegenerative diseases.