Intracranial Hypertension Threshold Definition
Intracranial hypertension is generally defined as a sustained intracranial pressure (ICP) above 20 mmHg in both adults and children, with treatment typically initiated at this threshold. 1
Standard Threshold Across Age Groups
The 20 mmHg threshold is consistently applied across pediatric populations, with the 2012 American Guidelines confirming that treatment of high ICP in children should be considered when ICP exceeds 20 mmHg 1
Multiple studies demonstrate a strong correlation between ICP >20 mmHg and favorable neurological outcomes (no, minor, or moderate disability) based on Glasgow Outcome Scale measurements in pediatric traumatic brain injury 1
ICP values >40 mmHg (or sometimes >35 mmHg) are strongly associated with unfavorable outcomes including death, vegetative state, and severe disability 1
Age-Related Considerations in Pediatric Patients
While the treatment threshold remains 20 mmHg, physiological ICP values vary with age in children:
ICP and cerebral perfusion pressure (CPP) are reduced in proportion to children's age, with values comparable to adults observed only after 6-8 years of age 1
Some data suggest the ICP threshold should be lower in younger children, particularly those under 6-8 years old, though the evidence requires further confirmation 1
Age-related ICP management strategies are supported by physiological data, with consideration for maintaining ICP below 20 mmHg in younger age groups 1
Context-Specific Applications
In Status Epilepticus (Refractory)
For pediatric patients with refractory status epilepticus, increased intracranial pressure is defined as CSF opening pressure ≥20 mmHg or clinical signs of increased intracranial pressure, requiring intensive-care management and osmotherapy 1
Continuous monitoring and early intervention are critical when ICP monitoring reveals sustained elevations above 20 mmHg in this population 1
In CAR T-Cell Therapy
- The same 20 mmHg threshold applies to pediatric patients receiving CAR T-cell therapy who develop cerebral edema as a complication of CAR T-cell-related encephalopathy syndrome (CRES) 1
Clinical Significance of Threshold Values
ICP between 20-40 mmHg is associated with a 3.95-fold increased risk (95% CI 1.7-7.3) of mortality and poor neurological outcome 1
ICP above 40 mmHg carries a 6.9-fold higher mortality risk (95% CI 3.9-12.4) compared to lower values 1
The incidence of raised ICP in severe pediatric traumatic brain injury ranges from 17-88%, making monitoring essential in at-risk populations 1
Important Caveats
The 20 mmHg threshold represents the point for treatment initiation, not necessarily the optimal target ICP, which should be individualized based on cerebral perfusion pressure and clinical response 1
In children under 2 years old, ICP monitoring is performed less frequently, yet this population remains at high risk for elevated ICP and poor outcomes, with a strong association between cerebral perfusion pressure and neurological outcome 1
Normal CT scan findings do not exclude the risk of intracranial hypertension, though the incidence is particularly low (0-8%) when initial CT is normal 1