Traumatic Brain Injury (TBI) Prognosis
OVERVIEW
Traumatic Brain Injury (TBI) is a devastating condition in terms of personal, societal and wider economic impact
- prognosis in TBI is difficult but important:
- guides appropriate treatment
- try to limit the proportion of patients left in a persistent vegetative state (PVS)
- aids the family in coming to terms with their loved one’s condition and with future planning
- clinical, physiological variables, radiological predictors and biological markers exist
- all are more useful for prediction at the population level than for guiding decisions concerning individual patients
TBI OUTOMES
MRC CRASH study in 2008 (n = 10,000 TBI patients with GCS <15) had these outcomes:
- 1 in 5 dead at 2 weeks
- 1 in 4 dead at 6 months
- 1 in 3 dead or severely disabled at 6 months
Extended Glasgow Outcome Scale is used to classify TBI outcomes, primarily in the research setting:
- Death
- PVS
- Severe disability: lower grade (dependent for ADLs), upper grade (self caring but unable to work)
- Moderate disability: lower grade (able to travel independently and work in sheltered environment), upper grade (able to work in reduced capacity, deficits in speech, memory and personality change)
- Good recovery: lower grade (can participate socially), upper grade (resumption of normal life, minor neurological/psychological deficits)
CLINICAL PREDICTORS
- age (>40 years, worse with increasing age)
- initial GCS post-resuscitation
- hypotension
- hypoxia
- pupil size and reaction to light (i.e fixed and dilated is bad!)
- ICP
- nature & extent of the intracranial injuries (worst to least, subdural -> extradural -> SAH)
- co-morbidities
- low-to-middle income countries
RADIOLOGICAL PREDICTORS
CT Brain
- obliteration of third ventricle/basal cisterns (absence of basal cisterns is the strongest predictor of six month mortality)
- midline shift
- petechial haemorrhages
- subarachnoid haemorrhage
- unevacuated hematoma
- brainstem injury
MRI
- at 6-8 weeks: injuries to corpus callosum, corona radiata and dorsolateral brainstem predict PVS
Experimental
- Diffusion tensor imaging
- allows detection of traumatic DI by providing information on integrity of white matter
- correlates with functional outcome at 1 year
- magnetic resonance spectroscopy
- measures brain metabolism and amounts of particular metabolites (creatinine, choline, lactate…)
- correlates with outcome
- SSEPs and cEEG
BIOMARKERS
Primarily experimental at present:
- serum S-100β protein (severe TBI biomarker that most consistently demonstrates the ability to predict injury and outcome in adults)
- neuron-specific enolase (NSE)
- IL-10
- myelin basic protein
- GFAP
- protein degradation products (e.g. spectrin breakdown product, c-tau, and amyloid-beta(1-42))
TBI PROGNOSIS CALCULATORS
These are based on prognostic models that combined data from patients involved in clinical trials to predict clinical outcome, and should be used with caution:
- their outcomes apply to populations — caution is needed if applying them to individual patients
- the models were externally validated against one another — they are yet to be validated on patients not selected from clinical trials
References and Links
CCC Neurocritical Care Series
Emergencies: Brain Herniation, Eclampsia, Elevated ICP, Status Epilepticus, Status Epilepticus in Paeds
DDx: Acute Non-Traumatic Weakness, Bulbar Dysfunction, Coma, Coma-like Syndromes, Delayed Awakening, Hearing Loss in ICU, ICU acquired Weakness, Post-Op Confusion, Pseudocoma, Pupillary Abnormalities
Neurology: Anti-NMDA Encephalitis, Basilar Artery Occlusion, Central Diabetes Insipidus, Cerebral Oedema, Cerebral Venous Sinus Thrombosis, Cervical (Carotid / Vertebral) Artery Dissections, Delirium, GBS vs CIP, GBS vs MG vs MND, Guillain-Barre Syndrome, Horner’s Syndrome, Hypoxic Brain Injury, Intracerebral Haemorrhage (ICH), Myasthenia Gravis, Non-convulsive Status Epilepticus, Post-Hypoxic Myoclonus, PRES, Stroke Thrombolysis, Transverse Myelitis, Watershed Infarcts, Wernicke’s Encephalopathy
Neurosurgery: Cerebral Salt Wasting, Decompressive Craniectomy, Decompressive Craniectomy for Malignant MCA Syndrome, Intracerebral Haemorrhage (ICH)
— SCI: Anatomy and Syndromes, Acute Traumatic Spinal Cord Injury, C-Spine Assessment, C-Spine Fractures, Spinal Cord Infarction, Syndomes,
— SAH: Acute management, Coiling vs Clipping, Complications, Grading Systems, Literature Summaries, ICU Management, Monitoring, Overview, Prognostication, Vasospasm
— TBI: Assessment, Base of skull fracture, Brain Impact Apnoea, Cerebral Perfusion Pressure (CPP), DI in TBI, Elevated ICP, Limitations of CT, Lund Concept, Management, Moderate Head Injury, Monitoring, Overview, Paediatric TBI, Polyuria incl. CSW, Prognosis, Seizures, Temperature
ID in NeuroCrit. Care: Aseptic Meningitis, Bacterial Meningitis, Botulism, Cryptococcosis, Encephalitis, HSV Encephalitis, Meningococcaemia, Spinal Epidural Abscess
Equipment/Investigations: BIS Monitoring, Codman ICP Monitor, Continuous EEG, CSF Analysis, CT Head, CT Head Interpretation, EEG, Extradural ICP Monitors, External Ventricular Drain (EVD), Evoked Potentials, Jugular Bulb Oxygen Saturation, MRI Head, MRI and the Critically Ill, Train of Four (TOF), Transcranial Doppler
Pharmacology: Desmopressin, Hypertonic Saline, Levetiracetam (Keppra), Mannitol, Midazolam, Sedation in ICU, Thiopentone
MISC: Brainstem Rules of 4, Cognitive Impairment in Critically Ill, Eye Movements in Coma, Examination of the Unconscious Patient, Glasgow Coma Scale (GCS), Hiccoughs, Myopathy vs Neuropathy, Neurology Literature Summaries, NSx Literature Summaries, Occulocephalic and occulovestibular reflexes, Prognosis after Cardiac Arrest, SIADH vs Cerebral Salt Wasting, Sleep in ICU
Journal articles
- Predicting outcome after traumatic brain injury: practical prognostic models based on large cohort of international patients. MRC CRASH Trial Collaborators. BMJ 2008;336:425 [Full Text]
- Nichol AD, Toal F, Fedi M, Cooper DJ. Early outcome prediction after severe traumatic brain injury: can multimodal magnetic resonance imaging assist in clinical prognostication for individual patients? Crit Care Resusc. 2011 Mar;13(1):5-8. PubMed PMID: 21355822. [fulltext pdf]
- Stevens RD, Sutter R. Prognosis in severe brain injury. Crit Care Med. 2013 Apr;41(4):1104-23. PMID: 23528755.
- Steyerberg EW, Mushkudiani N, Perel P, Butcher I, Lu J, et al. (2008) Predicting outcome after traumatic brain injury: Development and international validation of prognostic scores based on admission characteristics. PLoS Med 5: e165. doi:10.1371/journal.pmed.0050165.
- Young NH, Andrews PJD (2008) Developing a Prognostic Model for Traumatic Brain Injury—A Missed Opportunity? PLoS Med 5(8): e168. doi:10.1371/journal.pmed.0050168
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
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