From the Research
The cause of normal pressure hydrocephalus (NPH) is often unknown, though it can develop from conditions that affect cerebrospinal fluid (CSF) circulation, with recent studies suggesting that it may be multifactorial, including congenital causes, vascular disease, and impaired CSF absorption 1. In about 50% of cases, NPH is idiopathic, meaning no specific cause can be identified. Secondary causes include head trauma, subarachnoid hemorrhage, meningitis, brain tumors, or previous brain surgeries that disrupt normal CSF flow. NPH occurs when there is an imbalance between CSF production and absorption, leading to enlarged ventricles in the brain despite normal CSF pressure. This ventricular enlargement compresses surrounding brain tissue, particularly affecting areas controlling gait, bladder function, and cognition, which explains the classic triad of symptoms:
- walking difficulties
- urinary incontinence
- cognitive decline. The condition typically affects adults over 60 years old and is potentially reversible with proper treatment, usually through surgical placement of a shunt to divert excess CSF from the brain to another part of the body where it can be absorbed 2. Recent advances in non-invasive MRI methods, such as arterial spin-labeling (ASL), and the frequent association of NPH and obstructive sleep apnea (OSA), offer new avenues to understand and treat NPH 2. The diagnosis of NPH is based on a combination of clinical symptoms, radiological findings, and response to CSF withdrawal, with the use of programmable shunts and adjustable valves allowing for non-invasive management of overdrainage complications 1.