Management of Parenchymal Swelling in Normal Pressure Hydrocephalus (NPH)

Understanding Parenchymal Swelling in NPH

Parenchymal swelling in NPH often presents as transependymal edema, which is visible on MRI as periventricular lucencies and represents CSF seepage into brain tissue due to altered CSF dynamics, according to the American Academy of Neurology 1, 2
Transependymal edema is considered a hallmark of acute hydrocephalus and indicates active, potentially reversible pathology, as stated by the American Association of Neurological Surgeons 3, 1

Contrast-enhanced MRI is essential to evaluate the presence and extent of parenchymal swelling, ventriculomegaly, and to distinguish between communicating and non-communicating hydrocephalus, as recommended by the Infectious Diseases Society of America 3
Any changes in mental status, gait disturbance, incontinence, or cranial neuropathy should prompt neuroimaging to assess for progression of hydrocephalus and parenchymal swelling, according to the American College of Radiology 3
Opening pressure measurements during lumbar puncture may be suggestive of hydrocephalus, though ventricular fluid pressure may be normal in NPH, as noted by the American Academy of Neurology 3

Surgical CSF diversion via shunt placement is the recommended treatment for NPH with associated parenchymal swelling, as it addresses both the hydrocephalus and associated parenchymal swelling by normalizing CSF dynamics, according to the American Association of Neurological Surgeons 1
For acute presentation with increased intracranial pressure (ICP), initial management should include medical therapy and repeated lumbar punctures to stabilize pressure, as recommended by the Infectious Diseases Society of America 3
Endoscopic Third Ventriculostomy (ETV) may be considered in select cases, particularly when there is evidence of obstruction, as stated by the Congress of Neurological Surgeons 4, 1

In cases where hydrocephalus is secondary to another condition, the underlying cause should also be addressed, as recommended by the Infectious Diseases Society of America 5
If medical therapy with repeated lumbar punctures fails to stabilize increased ICP, prompt neurosurgical consultation for shunt placement is essential, according to the American College of Surgeons 3