(Idiopathic) normal pressure hydrocephalus

This code represents a chronic neurological condition characterized by an abnormal accumulation of cerebrospinal fluid (CSF) in the brain's ventricles, leading to ventricular enlargement without significantly elevated intracranial pressure. Patients typically present with a classic triad of symptoms: gait disturbance, urinary incontinence, and cognitive decline.

Use this code when documentation clearly indicates a diagnosis of idiopathic normal pressure hydrocephalus (iNPH). This diagnosis is often supported by imaging studies showing ventriculomegaly, clinical assessment of the characteristic symptom triad, and sometimes a positive response to a large volume lumbar puncture (LP) or CSF tap test.

• Differentiate from other forms of hydrocephalus (e.g., obstructive, communicating) where the etiology is known or intracranial pressure is elevated.
• Ensure documentation specifies "idiopathic" or "normal pressure" to support this specific code.
• Consider sequencing this code as the primary diagnosis when it is the main reason for the encounter and treatment.