Pathophysiology/Etiology
• ↑ pressure if any intracranial compartment → displaces other structures
• Brain tissue: ICH, neoplasm, infarct, DKA (young and new dx ↑ risk)
• CSF: CNS infection, vasculitis, hydrocephalus, pseudotumor cerebri
• Blood: Hemorrhage (TBI, ruptured AVM, other vascular anomalies)
• Mixed: DKA → cerebral edema (cytotoxic, vasogenic, or interstitial), TBI (see TBI section)
Clinical Manifestations
• Neuro: ΔMS, irritability, bulging fontanelle, HA, lethargy → coma, retinal hemorrhage, dilated pupil (usually on side of lesion), CN palsy (esp III, IV, VI), incontinence,
decorticate/decerebrate posturing
• Cardiorespiratory: Cushing triad (LATE – bradycardia, HTN, irregular respirations), Cheyne–Stokes breathing, apneusis
• GI: Vomiting
Diagnostic Evaluation
• Careful neurologic exam & fundoscopic exam; imaging: Head CT
• Labs: CMP (hypo- or hypernatremia), coags (bleeding can cause DIC, and for therapeutic intervention), CBC, and type and screen
• EKG: Cerebral T waves (deep T wave inversions)
• LP: Generally not recommended if concern for increased ICP. Treat empirically
Treatment (Pediatr Crit Care Med 2003;S65)
• Goals: Minimize ICP and maintain CPP
• Avoid 2° injury; avoid hypoxia, hypercarbia, HoTN, hypo/hyperglycemia, hyperthermia
• 1st-line therapy
• ABCs: Intubate if needed (GCS <8 on presentation is absolute indication)
• Thiopental or etomidate are drugs of choice; adequate sedation/analgesia
• Keep PCO2 35–40
• HOB 30° (J Neurosurg 1992;76:207), midline. Avoid neck access (CVL)
• Maintain normothermia (consider prophylactic Tylenol)
• Avoid hypervolemia. TF = ⅔–¾ mntc isotonic fluid; may need diuresis
• Treat underlying cause (Abx for infection, reduce IVF if DKA)
• Prophylactic antiepileptics (phenytoin, Keppra; phenobarbital in infant) for sz risk are standard of care but not evidence based
• 2nd-line therapy
• CSF drainage: Intraventricular drain w/ drainage and monitoring
• Maintain CPP (MAP–ICP): In TBI, autoregulation lost; CPP ∼ MAP, NE preferred
• Muscle relaxants to reduce shivering
• Suctioning adjuncts: Intratracheal lidocaine superior in preventing ICP spike (Intensive Crit Care Nurs 1996;12:303)
• Hyperosmolar therapy: Hypertonic saline, mannitol
• Therapeutic hypothermia (T 32–34°C): Reduces ICP but no ↓ mortality (adult data)
• Dexamethasone (0.25–0.5 mg/kg q6h) only beneficial for tumor-related vasogenic edema. Do not use in cerebral edema assoc with TBI, anoxic brain injury, intracerebral hemorrhage, or pediatric meningitis
• 3rd-line therapy
• Pentobarbital coma: For refractory cases
• Decompressive craniectomy. Absolute indications: Refrac ICP, ICP >40 for >30 min
Dosages are suggestions and do not replace clinical judgment. Follow institutional guidelines where available.
Prognosis (J Pediatr 2002;141:793)
• Mortality: Severe TBI ∼8%, severe TBI w/ either HoTN, hypoxia, or hypercarbia ∼55%
• Other poor prognostic signs: Hyper-/hypoglycemia (TBI), ↑ BUN, GCS ≤ 7, PCO2 < 22 (DKA), hypoxia, hypercarbia, each episode of HoTN leads to worse neurologic disability
Pediatric Brain Death Criteria (Crit Care Med 2011;39:2139)
• Definition: Absent neurological fxn w/ known irreversible cause of coma and apnea
• Prerequisites: HoTN, hypothermia and metabolic abn corrected; sedatives, NM blockers, anti-convulsants d/c’d for reasonable duration prior to exam. Exam 24–48 hr after resuscitation or acute brain injury
• Criteria
• 2 neuro exams (2 diff attendings) 12–24 hr apart w/: Coma (LOC, unresponsive to noxious stim, no purposeful mvmt), absent brain stem reflexes (no pupillary resp [CNII], absent corneal resp), Absent gag, cough, sucking, rooting reflexes (CN IX, X), absent oculovestibular reflex (CN XIII; cold water caloric testing w/o eye deviation or nystagmus), absent facial mvmt (CN VII, no grimace w/ deep pressure at supraorbital ridge), flaccid tone (w/ exception of spinal cord reflexes)
• Apnea testing ×2 (can be the same provider); begin by ventilation/oxygenation to nml parameters. Cease support and PaCO2 must rise 20 mm Hg (>60 mm Hg abs) w/o resp effort; terminate test if desat or pt destabilizes. Can sub ancillary testing for apnea
• Ancillary testing: Not necessary; EEG, NM scan, cerebral blood flow, angiography; these can be substituted for apnea testing but does not replace neuro exam