What to do when hydrocephalus worsens with an External Ventricular Drain (EVD) in place?

Management of Worsening Hydrocephalus with EVD in Place

When hydrocephalus worsens despite an EVD in place, immediately verify EVD patency and positioning, optimize drainage parameters, and consider adding intraventricular thrombolytic therapy if intraventricular hemorrhage is present. 1

Immediate Assessment and Troubleshooting

Verify EVD Function

• Check for EVD malposition or migration through urgent CT imaging, as catheter displacement can cause inadequate drainage and clinical deterioration 2
• Assess for catheter obstruction by blood clot or debris, particularly in patients with intraventricular hemorrhage 1
• Confirm drainage parameters are appropriate (typically set at 10-15 cm H2O above the tragus) 3
• Measure actual CSF output volume—inadequate drainage (<250 mL/24 hours may indicate obstruction) 4

Clinical Deterioration Indicators

• Monitor for declining Glasgow Coma Scale score, new pupillary changes, or signs of transtentorial herniation 1, 3
• Obtain urgent neuroimaging to assess ventricular size progression and rule out new hemorrhage or mass effect 1

Therapeutic Interventions

Optimize EVD Management

• Lower the drainage height to increase CSF outflow if ICP remains elevated despite current settings 3, 4
• Consider continuous drainage rather than intermittent if not already implemented 5
• Ensure the EVD bundle protocol is being followed to minimize infection risk (which can worsen hydrocephalus) 3

Add Intraventricular Thrombolytic Therapy

• For patients with intraventricular hemorrhage and GCS >3, adding alteplase or urokinase to EVD irrigation significantly reduces mortality compared to EVD with saline alone 1
• The 2022 AHA/ASA guidelines give this a Class 2a recommendation based on the CLEAR III trial and multiple meta-analyses 1
• Thrombolytic irrigation hastens clot removal and improves CSF circulation 1
• This approach is safe with no increased risk of symptomatic hemorrhage, and actually shows lower rates of ventriculitis 1

Consider Additional or Alternative Drainage

• Place a second EVD if the first is malpositioned or if multiloculated hydrocephalus is present 6
• Consider lumbar drainage as an adjunct if communicating hydrocephalus is confirmed and no mass effect exists 1, 3
• Neuroendoscopic intervention may be reasonable for loculated ventricles or septated hydrocephalus, though evidence for functional outcomes is uncertain 1

Addressing Underlying Causes

Rule Out Complications

• Infection/ventriculitis can worsen hydrocephalus—obtain CSF studies if fever, elevated white blood cell count, or clinical deterioration occurs 3, 6
• New hemorrhage or rebleeding (in aneurysmal SAH) can obstruct CSF pathways 1, 6, 7
• Cerebral vasospasm in SAH patients may contribute to clinical worsening independent of hydrocephalus 1, 8

Timing Considerations

• In aneurysmal SAH, acute hydrocephalus occurs in 15-87% of patients and may evolve over the first days to weeks 1, 3
• Delayed worsening may indicate transition to chronic hydrocephalus requiring permanent shunt placement 1, 3, 9

Transition to Definitive Management

When to Consider Permanent CSF Diversion

• Chronic symptomatic hydrocephalus should be treated with permanent CSF diversion (ventriculoperitoneal shunt) per AHA/ASA Class I recommendation 1, 3, 9
• This occurs in 8.9-48% of SAH patients and 11% of patients managed with standardized EVD protocols 3, 9, 4
• Predictors of shunt dependency include poor admission grade, older age, high Fisher grade, presence of IVH, and prolonged EVD duration 3
• Prolonged EVD weaning (>24 hours) does not reduce shunt dependency and should not be routinely performed 1, 9

Common Pitfalls to Avoid

• Do not assume the EVD is functioning properly without imaging confirmation—malposition and migration occur and can cause acute deterioration 2
• Do not delay imaging when clinical worsening occurs—urgent CT is essential to guide management 1
• Do not overlook infection as a cause of worsening hydrocephalus, particularly with prolonged EVD duration 3, 6
• Do not continue ineffective EVD management—if standard measures fail, escalate to thrombolytic therapy (if IVH present) or consider additional drainage 1
• In aneurysmal SAH, do not attribute all neurological worsening to hydrocephalus alone—consider vasospasm, rebleeding, and seizures as concurrent issues 1, 8