Chronic communicating hydrocephalus is a neurological condition characterized by the accumulation of cerebrospinal fluid (CSF) in the brain's ventricles due to impaired absorption, rather than obstruction of CSF flow. The term “communicating” refers to the fact that the ventricular system remains open and connected — CSF can still flow between the ventricles and the subarachnoid space, but reabsorption by the arachnoid granulations is reduced.
Subarachnoid hemorrhage (e.g., after trauma or aneurysm rupture)
Meningitis or other infections
Post-surgical or post-radiation changes
Congenital conditions
Idiopathic (especially in older adults, e.g., idiopathic normal pressure hydrocephalus)
In chronic cases, especially in adults:
Gait disturbance (often the earliest and most prominent symptom)
Urinary incontinence
Cognitive impairment (memory loss, slowed thinking, apathy)
This classic triad is characteristic of normal pressure hydrocephalus (NPH), a subtype of chronic communicating hydrocephalus.
Neuroimaging (CT or MRI): Enlarged ventricles without cortical atrophy.
Lumbar puncture or CSF tap test: Temporary symptom improvement after CSF drainage can support diagnosis.
ICP monitoring (occasionally): May show normal or intermittently elevated pressures.
Ventriculoperitoneal (VP) shunt: Diverts CSF to the peritoneal cavity.
Endoscopic third ventriculostomy (ETV): Less commonly used for communicating hydrocephalus (more often for non-communicating/obstructive forms).