Idiopathic normal pressure hydrocephalus (INPH) is a treatable neurological 
disorder in older adults involving disturbances of gait/balance, control of 
micturition, and/or cognition in combination with enlargement of the cerebral 
ventricles. Diagnosis can be challenging due to its varied presentation and 
overlap with other disorders common in the elderly. Evidence-based consensus 
guidelines for diagnosis and treatment of INPH have been created that can assist 
in clinical management. Diagnosis requires clinical documentation of one or more 
of the characteristic symptoms of INPH in combination with a brain imaging study 
demonstrating nonobstructive ventricular enlargement disproportionate to 
cerebral atrophy. Gait and balance disturbances are the most common presenting 
findings in INPH and may occur alone or together with cognitive and urinary 
symptoms. Adjunct tests, particularly those involving transient removal of 
cerebrospinal fluid via lumbar puncture or lumbar drain, can serve the dual 
purpose of adding to diagnostic certainty and assisting in prognostication about 
response to treatment. Prognostication is important because neurosurgical 
treatment by placement of a ventricular shunt, while effective, carries the risk 
of potentially significant morbidity. Outcome of shunting in INPH is most often 
successful when patients are accurately diagnosed, suitably evaluated for 
surgical candidacy, and managed carefully throughout the preoperative, surgical, 
and postoperative periods.