Diagnosis and Management for Secondary Low- or Negative-Pressure Hydrocephalus and a New Hydrocephalus Classification...

Low-pressure hydrocephalus (LPH) and negative-pressure hydrocephalus (NegPH), secondary to traumatic brain injury, cerebral hemorrhage, tumor resection, and central nervous system (CNS) infection in adults, are seldom reported. They have not been recognized enough pathophysiologically in previous clinical practice. They used to have poor prognosis, and routine shunt surgery has unsatisfactory outcomes. The current classifications of hydrocephalus do not provide proper guidance for clinical practice, especially for LPH and NegPH.

Thirty-nine cases of LPH and NegPH were included from January 2013 to March 2018. Clinical features and image characteristics were reviewed. The prognosis of these patients were evaluated by Glasgow Outcome Scale-Extended (GOS-E) within 3 months after external ventricular drainage or ventriculoperitoneal (VP) shunt accepted. Management strategies were discussed in detail.

Ventricular pressure was lower than 70 mm H₂O in all 39 patients, and the lowest value was -10 cm H₂O. About an average of 3.5 operations were completed for every patient. Eighteen cases had CNS infection. Eight patients died. Besides 2 patients lost to follow-up, all patients had a poor prognosis with an average GOS-E score of 2.7. For the 29 surviving patients, the time interval from onset to last VP shunt achieved was 31-3880 days, with an average of 376 days.

Both LPH and NegPH used to have poor prognosis. However, a good prognosis can be achieved by proper management with a further understanding of the pathophysiology. A new classification for hydrocephalus was proposed according to ventricular pressure, which is necessary and reasonable.