OVERVIEW: EARLY PROGNOSTICATORS OF FUNCTIONAL OUTCOMES

  1. Intelligence
    • Missile injury - Greater premorbid intelligence implies greater residual functional outcome
    • Blunt injury - Severe blunt injuries result in uniform cognitive defects, regardless of premorbid intelligence. However, lower premorbid intelligence lessens the chance of the individual returning to work

  2. Age is a strong indicator or both mortality and functional outcome
    • <40 is generally predictive of good outcome
    • >50 is generally predictive of poor outcome
    • >60 is associated with a significant increase in poor outcome (Brain Trauma Foundation, 2000 c)

  3. Coma
    • Coma duration - Particularly in patients with diffuse axonal injuries, without focal or extracerebral lesions:
      • Coma duration of <2 weeks is predictive of good outcome
      • Coma duration of >2 weeks is predictive of poor outcome
    There appears to be a linear relationship between recovery and coma duration.

    • Depth of coma
      • Glasgow Coma Scale
        • Within 24 hours
          • <8 have a higher mortality rate or risk of a vegetative state
          • >8 have a very low mortality rate
        • After 24 hours
          • < or = 5 is predictive of poor outcome
          • >5 is predictive of good outcome
    The two most important problems with using the GCS for prognosis are the reliability of the initial measurement and its lack of prediction if the initial GCS is low (Brain Trauma Foundation, 2000 d)

  4. Posttraumatic Amnesia (PTA) Duration
    • < 2 weeks of PTA is predictive of good recovery
    • > 12 weeks of PTA is predictive of poor recovery

  5. CT Scans - Mass lesions, particularly lesions with a volume >4100 mm3, generally indicate a higher mortality rate and poorer functional outcome
    • Subdermal hematomas are indicative of the highest mortality rates and poorest functional outcomes
    • Third ventricle and basal cistern abnormalities indicate poor functional outcome
    • Temporal lobe lesions are generally predictive of poor functional outcome if the resulting midline shift is > 4 mm
    • Basal ganglion lesions are rare, but carry a fairly good prognosis
    • Either midline shift greater than 5mm or a subcortical contusion on acute CT scans is associated with a greater need of assistance with ambulation, ADLs, and global supervision at rehabilitation discharge. Patients with bilateral cortical contusions require more global supervision at rehabilitation discharge but no more supervision for ambulation and ADLs (Englander, et al 2003)

  6. ICP - Elevated ICP is usually predictive of poor outcome, particularly if sustained above 30 mmHg for several hours despite aggressive therapy. Early intracranial hypertension is also a sign of poor prognosis (Signorini, et al 1999). Since patients with disturbed pressure reactivity in the first 24 hours after injury had a significantly higher mortality rate than patients with intact pressure reactivity, patients with severe TBI who have early loss of autoregulation have a worse prognosis (Hiler, et al 2006).

    Serum S100B is a sensitive bio marker for early prediction of the development of high intracranial pressure and fatal outcome following acute brain injury. Monitoring S100B concentrations could contribute to early detection of patients at risk of scondary increases in intracranial pressure and subsequent mortality and allow earlier targeting of therapy in selected patients (Petzold, et al 2002). Serum S100B is a sensitive marker of brain injury, which correlates with the severity of the injury (Savola, et al 2004).

  7. Hypotension, (systolic blood pressure of <90 mmHg) occurring at any time from injury through the acute intensive care course, is a primary predictor of outcome from severe head injury; one of the five most powerful predictors of outcome; and generally the only one of these five that is amenable to therapeutic modification. A single recording of a hypotensive episode is generally associated with a doubling of mortality and a marked increase in morbidity from a given head injury (Brain Trauma Foundation, 2000 a)

  8. Pupillary Diameter and Light Reflex - Accurate measurement of pupil diameter or the constrictor response or the duration of the response has lacked a standardized measuring procedure. The following is recommended: 1) Pupillary light reflex for each eye should be used as a prognostic parameter. 2) The duration of pupillary dilation and fixation should be documented. 3) A pupillary size of >4mm is recommended as the measure for a dilated pupil. 4) A fixed pupil should be defined as no constrictor response to bright light. 5) Right or left distinction should be made when the pupils are asymmetric. 6) Hypotension and hypoxia should be corrected before assessing pupils for prognosis. 7) Direct orbital trauma should be excluded. 8) Pupils should be reassessed after surgical evacuation of intracranial hematomas (Brain Trauma Foundation, 2000 b)

  9. Other reliable indicators of poor functional outcomes:
    • Hypoxia, defined as apnea/cyanosis in the field or a PaO2 <60 mmHg by arterial blood gas analysis (Brain Trauma Foundation, 2000 m)
    • Absence of cerebral blood flow (CBF)
    • Cerebral venous saturation (Prough & Lang, 1997)
    • EEG, particularly no electrical activity even at high gain. Continuous EEG monitoring, performed with particular attention paid to the percentage of alpha variability, can predict outcomes in patients with moderate to severe TBI within 3 days postinjury (Vespa, et al 2002)
    • Location of lesions - In patients in the early post-traumatic vegetative state, injuries of the corpus callosum and dorsolateral brainstem detected by MRI are predictive of non-recovery (Kampfl, et al 1998). Poor prognosis is more common in TBI patients with brainstem injury (Mannion, et al 2007).
    • Number of lesions - More then 4 lesions in the frontal cortex or 3 in the braintem have been linked to unfavorable outcome (Hoelper, et al 2000)
    • SSEP (somatosensory evoked potentials), particularly when applied serially in severe brain injury (Pohlmann-Eden, et al 1997). Unilateral absence of the cortical component of the SSEP was usually associated with poor outcome, and bilateral absence was always associated with poor outcome (Sleigh, et al 1999)
    • Longer duration of adverse physiological events, such as ICP, MAP, and CPP (Struchen, et al 2001)
    • APOE (apolipoprotein E) genotype, which has been linked to poorer memory performance following TBI (Crawford, et al 2002); may influence the severity of the acute injury, but not necessarily the rate of recovery from mild brain injury (Liberman, et al 2002; Chamelian, et al 2004); is associated with larger hematomas that may contribute to the poorer outcomes of patients with 1 or more APOE alleles (Liaquat, et al 2002); and is associated with increased risk of late posttraumatic seizures which appears to be independent of an effect on functional outcome (Diaz-Arrastia, et al 2003). Presence of cerebral amyloid angiopathy in head injured cases is significantly associated with possession of an APOE epsilon 4 allele but not with the severity of contusions (Leclerq, et al 2005).
    • Asymmetry, the left-hand differnce in autoregulation, is significantly associated with a fatal outcome. Autoregulation in the brain is worse on the side ipsilateral to the lesion and on the side of expansion in cases in which there is a midline shift. It is correlated with a midline shift (Schmidt, et al 2003)
    • Subarachnoid hemorrhage appears to be associated with worse vocational outcomes (Hanlon, et al 2005).
    • Impaired percent alpha variability (PAV) on continuous EEG predicts poor long-term outcome (Hebb, et al 2007).

      Click on Prognosis in Penetrating Brain Injury for conclusions regarding age, suicide, perforating injuries, weapon caliber, hypotension, coagulopathy, respiratory distress, GCS scale, fixed and dilated pupils, ICP, features on CT scans, etc.

Based on information in Medical Rehabilitation of Traumatic Brain Injury, L.J. Horn and N.D. Zasler, eds. St. Louis, MO, Mosby, 1996, except for information where other papers are cited.