Causes: brain injury, tumor, hydrocephalus, arteriovenous malformations, cerebral edema, hemorrhage (epidural, subdural, subarachnoid, intracerebral), superior vena caval syndrome, stroke, encephalitis, meningitis, traumaPathogenesis: increased intracerebral mass, increased CSF volume, increased intravascular blood volume, increased interstitial fluid, hemorrhage 1900 ml fixed volume in skull is 85% brain (5% extracellular fluid, 45% glial, 35% neural), 7% blood, 7% CSF increased intracranial pressure (ICP) may remain constant for a while due to shunting of blood of CSF effects of hypoxemia on cerebral metabolism and function PaO2 < 50 mm Hg, central venous PO2 < 35 mm Hg - increased glycolysis and lactate production, normal high-energy phosphates, decreased neurotransmitters; impaired learning, minor EEG change PaO2 < 35 mm Hg, central venous PO2 < 25 mm Hg - pronounced lactate production, normal energy charge; abnormal psychologic test, altered behavior, impaired judgment PaO2 < 20-25 mm Hg, central venous PO2 < 10-15 mm Hg - decreased ATP and energy charge, increased NADH/NAD+ ratio; loss of consciousness; EEG slowed or absent PaO2 < 5-10 mm Hg, tissue PO2 < 2 mm Hg - impaired mitochondrial function, permanent damage to some neurons; death from cardiovascular failureHistory and PhysicalHistory: Chief concern (CC): headache, nausea, vomiting, clouded mentationHistory of present illness (HPI): duration of loss of consciousnessPhysical: General physical: Cushing reflex (bradycardia, hypertension) from pressure on brainstemHEENT: papilledema picture of papilledema associated with intracranial hypertension can be found in N Engl J Med 2001 May 10;344(19):1442 picture of papilledema associated with intracranial hypertension can be found in Lancet 2001 Jun 16;357(9272) intracranial pressure > 28 cm H2O significantly higher in children with optical nerve head edema than age-matched controls (Neurology 2011 May 10;76(19):1658) venous pulsations seen on funduscopy suggests that intracranial pressure is normal, although patients with normal intracranial pressure may not have venous pulsations (Arch Neurol 1978 Jan;35(1):37 in N Engl J Med 1999 Jul 8;341(2):129), commentary can be found in BMJ 2004 Jul 24;329(7459):209 sixth nerve palsy bulging fontanelles and splitting of sutures in infants basilar fracture often associated with ecchymosis behind ear (Battle's sign) anterior basilar fracture often with periorbital ecchymosis (raccoon's eyes) and subconjunctival hemorrhage hematotympanum associated with fracture of middle fossa paralysis of upward gaze (Parinaud's syndrome) light-near dissociation light reflex may be disrupted in midbrain pretectal region without damage to more ventral near reflex fibers; anatomic lesion is pretectal internuncial neurons serving reflex pupil constriction to light Parinaud's syndrome is usually caused by pinealomas or other dorsal midbrain lesions pupils are relatively large, often slightly unequal; convergence-retraction nystagmus on attempted upgaze; constriction to light is absent or very weak, but response to near stimulus is normalNeuro: Glasgow Coma Scale (GCS) eye opening - spontaneously 4, on command 3, with pain 2, none 1 motor - obeys commands 6, localizes pain 5, withdraws 4, flexion (decorticate) 3, extension (decerebrate) 2, none 1 vocal - oriented 5, confused 4, inappropriate speech 3, incomprehensible sounds 2, none 1 range 3-15, change of 2 or more considered significantDiagnosisTesting overview: type and cross CT head (without contrast to detect hemorrhage) MRIImaging studies: CT - fresh blood hyperdense (epidural hematoma semilunar with convexity toward brain, acute subdural with concavity toward brain, SAH dense subarachnoid space), cerebral edema indicated by size of ventricles and basal subarachnoid cisterns x-ray cervical spine to rule out associated spinal injuries skull x-ray to screen for fracture if less severe injuries intracranial air, clouding of sinuses suggests CSF leak suspect epidural hematoma if fracture line crosses groove of middle meningeal vessels clouding of mastoid air cells or sphenoid sinus suggests basilar skull fracture measurement of optic nerve sheath ultrasonography of optic nerve sheath diameter (ONSD) may aid diagnosis of intracranial hypertension (level 2 [mid-level] evidence) based on systematic review with inadequate reporting of study quality assessment systematic review of 6 prospective cohort studies evaluating ultrasonography of ONSD for detection of intracranial hypertension in 231 patients reference standard included intraparenchymal and intraventricular intracranial pressure monitoring prevalence of intracranial hypertension not reported conditions included traumatic brain injury intracerebral hemorrhage subarachnoid hemorrhage stroke (acute management) intracranial hematoma pooled diagnostic performance of ultrasonography of ONSD for detection of raised intracranial pressure sensitivity 90% (95% CI 80%-95%) specificity 85% (95% CI 73%-93%) positive likelihood ratio 6.11 (95% CI 3.28-11.37) negative likelihood ratio 0.12 (95% CI 0.06-0.23) Reference - Intensive Care Med 2011 Jul;37(7):1059 EBSCOhost Full Text sonographic optic nerve sheath measurement does not appear to adequately predict increased intracranial pressure (ICP) in children based on cohort of 64 children with suspected increased ICP who received emergency physician-performed measurement of optic nerve sheath diameter 37% confirmed diagnosis of increased ICP (by cranial imaging or direct ICP measurement) optic nerve sheath measurement to predict increased ICP 83% sensitive 38% specific positive likelihood ratio 1.32 negative likelihood ratio 0.46 fair to good interobserver agreement between pediatric emergency physician, ophthalmic sonographer and pediatric ophthalmologist Reference - Ann Emerg Med 2009 Jun;53(6):785 optic nerve sheath diameter may correlate with transcranial Doppler sonography and invasive measures in adult patients with brain injury (level 2 [mid-level] evidence) based on cohort study without validation 76 patients (mean age 47 years) in intensive care had intracranial pressure (ICP) measured by transcranial Doppler sonography, optic nerve sonography and invasive testing (if severe brain injury) 66% had brain injury optic nerve sheath diameter cut-off value 5.7 mm associated with 74% sensitivity and 100% specificity optic nerve sheath diameter measurements significantly correlated with estimated and invasive ICP measurements in patients with moderate and severe brain injury Reference - Crit Care 2008;12(3):R67full-textTreatmentTreatment overview: emergency management establish adequate ventilation control hemorrhage maintain peripheral vascular circulation stabilize neck with hard cervical (Philadelphia) collar or sandbags guidelines for management of severe traumatic brain injury joint project of Brain Trauma Foundation, American Association of Neurological Surgeons and Congress of Neurological Surgeons see traumatic brain injury for additional guidelines not specific to intracranial hypertension initial management insufficient data to support standards or guidelines, so all recommendations listed as options first priority is for complete and rapid physiologic resuscitation indications for specific treatment directed at intracranial hypertension should only be done if signs of transtentorial herniation or progressive neurologic deterioration not attributable to extracranial explanations should be done presumptively and aggressively if signs of transtentorial herniation or progressive neurologic deterioration not attributable to extracranial explanations specific treatment directed at intracranial hypertension hyperventilation should be rapidly established mannitol administration desirable but only under conditions of adequate volume resuscitation sedation and neuromuscular blockade can be useful in optimizing transport, but interfere with neurological exam neuromuscular blockade should be used when sedation alone proves inadequate short-acting agents should be used when possible critical pathway for treatment of intracranial hypertension insert intracranial pressure (ICP) monitor maintain cerebral perfusion pressure > 70 mm Hg ventricular drainage (if available) hyperventilation to PaCO2 30-35 mm Hg mannitol 0.25-1 g/kg IV, may repeat if serum osmolarity < 320 mOsm/L and patient euvolemic consider repeating computed tomography (CT) scan and carefully withdrawing ICP treatment once controlled second tier therapies for refractory intracranial hypertension high-dose barbiturate therapy hyperventilation to PaCO2 < 30 mm Hg, with additional monitoring to identify cerebral ischemia indications for ICP monitoring insufficient data to support standards, so recommendations presented as guidelines ICP monitoring appropriate for patients with severe head injury (GCS 3-8 after cardiopulmonary resuscitation) with abnormal admission CT scan (hematomas, contusions, edema, or compressed basal cisterns) normal CT scan and 2 or more of: age > 40 years unilateral or bilateral motor posturing systolic blood pressure < 90 mm Hg ICP monitoring not routinely indicated in mild or moderate head injury, but may be used in certain conscious patients with traumatic mass lesions ICP treatment threshold insufficient data to support standards guidelines - ICP treatment should be initiated at upper threshold of 20-25 mm Hg options - interpretation and treatment of ICP based on any threshold should be corroborated by frequent clinical exam and cerebral perfusion pressure data recommendation for ICP monitoring technology ventricular catheter connected to external strain gauge is most accurate, low-cost, reliable method and allows therapeutic cerebrospinal fluid drainage ICP transduction via fiberoptic or strain gauge devices placed in ventricular catheters have similar benefits but higher cost parenchymal ICP monitoring has potential for measurement drift subarachnoid, subdural and epidural monitors less accurate guidelines for cerebral perfusion pressure insufficient data to support standards or guidelines, so all recommendation listed as option cerebral perfusion pressure should be maintained at minimum of 70 mm Hg hyperventilation standard - in absence of increased ICP, chronic prolonged hyperventilation therapy (PaCO2 < 25 mm Hg) should be avoided after severe traumatic brain injury guideline - use of prophylactic hyperventilation (PaCO2 < 35 mm Hg) during first 24 hours after severe traumatic brain injury should be avoided due to compromised cerebral perfusion options hyperventilation therapy may be necessary for brief periods of acute neurological deterioration hyperventilation therapy may be necessary for longer periods if intracranial hypertension refractory to sedation, paralysis, cerebrospinal fluid drainage, and osmotic diuretics methods which may help identify cerebral ischemia if hyperventilation (resulting in PaCO2 < 30 mm Hg) is necessary jugular venous oxygen saturation arterial jugular venous oxygen content differences brain tissue oxygen monitoring cerebral blood flow monitoring use of mannitol insufficient data to support standards guideline - mannitol (0.25-1 g/kg body weight) effective for control of increased ICP after severe head injury options indications for use of mannitol prior to ICP monitoring are signs of transtentorial herniation or progressive neurologic deterioration not attributable to extracranial explanations, but avoid hypovolemia by fluid replacement maintain serum osmolarity < 320 mOsm to avoid renal failure maintain euvolemia with adequate fluid replacement, Foley catheter essential intermittent boluses may be more effective than continuous infusion use of barbiturates in control of intracranial hypertension insufficient data to support standards, so recommendations presented as guideline high-dose barbiturate therapy may be considered in hemodynamically stable salvageable severe head injury patients with intracranial hypertension refractory to maximal medical and surgical ICP lowering therapy steroids NOT recommended for improving outcome or reducing ICP in patients with severe head injury (Standard of care) Reference - Brain Trauma Foundation Guidelines 2007 (J Neurotrauma 2007;24 Suppl 1:S1) cerebral perfusion pressure-targeted therapy may reduce 90-day mortality compared to intracranial pressure-targeted therapy in children with acute central nervous system infection and elevated intracranial pressure (level 2 [mid-level] evidence)Activity: elevate head 30 degrees keep head midline (with sandbags) to avoid occluding jugular veins (also avoid using internal jugular venous access lines) elevating head increases cerebral perfusion pressure gradient (mean arterial pressure - central venous pressure), promotes venous drainage passive range of motion to prevent joint contractures as soon as such stimulation does not cause dangerous increase in ICPMedications: IV fluids - volume replacement isotonic fluids - Ringer lactate, normal saline, blood, 5% albumin, FFP, PRBCs consider colloid or blood products to decrease risk of cerebral edema fluid bolus if necessary for hypotension cerebral perfusion pressure-targeted therapy may reduce 90-day mortality compared to intracranial pressure-targeted therapy in children with acute central nervous system infection and elevated intracranial pressure (level 2 [mid-level] evidence) based on randomized trial without blinding 110 children (aged 1-12 years) with acute central nervous system infection and elevated intracranial pressure were randomized to 1 of 2 pressure-targeted therapies and followed to 90 days after discharge maintaining cerebral perfusion pressure 60 mm Hg with normal saline bolus plus dopamine (and noradrenaline if needed) maintaining intracranial pressure < 20 mm Hg with osmotherapy while maintaining normal blood pressure comparing cerebral perfusion-targeted therapy vs. intracranial pressure-targeted therapy 90-day mortality 18.2% vs. 38.2% (p = 0.02, NNT 5) hearing deficit in 8.9% vs. 37.1% (p = 0.005, NNT 4) median length of pediatric intensive care unit stay 13 days vs. 18 days (p = 0.002) median duration of mechanical ventilation 7.5 days vs. 11.5 days (p = 0.003) compared to intracranial pressure-targeted therapy, cerebral perfusion-targeted therapy also associated with increased modified Glasgow Coma Scale score at all time points evaluated (p < 0.001 for each) Reference - Crit Care Med 2014 Apr 1 early online 20% mannitol may be less effective than hypertonic saline for controlling elevated intracranial pressure (level 3 [lacking direct] evidence) based on systematic review of trials without blinding and without clinical outcomes systematic review of 5 small randomized trials comparing mannitol vs. hypertonic saline (3%-7.5%) in 112 patients with elevated intracranial pressure (184 total episodes) hypertonic saline associated with slightly improved control of elevated intracranial pressure (relative risk 1.16, 95% CI 1-1.33, p = 0.046) in analysis of 5 trials Reference - Crit Care Med 2011 Mar;39(3):554, editorial can be found in Crit Care Med 2011 Mar;39(3):601 hypertonic saline may reduce intraoperative brain tension compared to mannitol in patients having craniotomy for brain tumor (level 3 [lacking direct] evidence), insufficient evidence to evaluate effect on mortality or function based on nonclinical outcome in Cochrane review systematic review of 6 randomized trials comparing hypertonic saline vs. mannitol in 527 patients having craniotomy for brain tumor hypertonic saline associated with decreased intraoperative brain tension in analysis of 3 trials with 387 patients risk ratio 0.6 (95% CI 0.44-0.83) NNT 5-17 with intraoperative brain tension in 36% of mannitol group no significant difference in duration of intensive care unit and hospital stay in 1 trial with 238 patients no trials reported on mortality, functional outcome at 3 months, quality of life, or adverse events Reference - Cochrane Database Syst Rev 2014 Jul 12;(7):CD010026 barbiturates thiopental may decrease intracranial hypertension compared to pentobarbital in patients with traumatic brain injury (level 3 [lacking direct] evidence) based on small randomized trial without clinical outcomes 44 patients with severe traumatic brain injury Glasgow coma scale score 8 after resuscitation and refractory intracranial hypertension > 20 mm Hg were randomized to pentobarbital 10 mg/kg IV loading dose given over 30 minutes followed by continuous perfusion 5 mg/kg per hour for 3 hours, followed by maintenance dosage 1 mg/kg per hour thiopental 2 mg/kg IV bolus given over 20 seconds, if ICP not < 20 mm Hg, then re-bolus with 3-5 mg/kg if ICP not < 20 mm Hg per protocol, followed by maintenance dosage 3 mg/kg per hour baseline differences in cranial computed tomography between groups uncontrollable intracranial pressure in 50% thiopental group vs. 82% pentobarbital group (p = 0.03) no significant difference between groups in adverse events Reference - Crit Care 2008;12(4):R112full-textSurgery and procedures: partial or total resection of tumor ventriculostomy useful only for hydrocephalus craniotomy (burr holes), opening of sutures hemicraniectomy rarely used remove bone flap useful for hemispheric trauma decompressive craniectomy reported to reduce refractory high intracranial pressure (ICP) in children with traumatic brain injury (level 3 [lacking direct] evidence) based on small randomized trial 27 children (median age 10.1 years) with traumatic brain injury and with intraventricular catheters were randomized to early decompressive bitemporal craniectomy followed by standard care vs. standard care alone median Glasgow Coma Scale score 5 in control group and 6 in treatment group at admission bitemporal craniectomy was done at median 19.2 hours goal was ICP < 20 mm Hg and cerebral perfusion pressure > 50 mm Hg comparing children in decompression group vs. control decrease in mean ICP from time of injury to 48 hours after randomization was 9 mm Hg vs. 3.7 mm Hg (p = 0.057) median time in intensive care unit 9.6 days vs. 12.8 days (not significant) median hospital stay 26.8 days vs. 47.7 (not significant) comparing surviving children in decompression group vs. control at 6 months after injury Glasgow Outcome Score favorable in 54% vs. 14% (not significant) Glasgow Outcome Score unfavorable in 46% vs. 86% (not significant) deaths occurred in 3 children in decompression group vs. 6 children in control group (statistics not given) Reference - Childs Nerv Syst 2001 Feb;17(3):154 no additional trials evaluating patients 12 months old identified in Cochrane review (Cochrane Database Syst Rev 2008 Oct 8;(4):CD003983) decompressive surgery within 48 hours of onset of massive acute ischemic stroke with cerebral edema may reduce mortality (level 2 [mid-level] evidence) based on 2 meta-analyses of 3 randomized trials with unclear allocation concealment see Stroke (acute management) for detailsOther management: hypothermia - adjunct - lower core temperature to 89.6-93.2 degrees F (32-34 degrees C)Complications and PrognosisComplications: irreversible ischemic injury to brain, herniationPrognosis: GCS at 6 hours is a good predictor, poor prognosis in adults with GCS < 7 at 6 hoursPrevention and ScreeningPrevention: prevent or treat underlying cause