From the Guidelines
The prognosis of diffuse axonal injury (DAI) is highly variable, with the most recent and highest quality study suggesting that approximately 27% of patients with mild TBI and normal CTs show abnormalities on early MRI, which may be clinically relevant in improving prediction of 3-month outcomes 1.
Factors Influencing Prognosis
The prognosis of DAI varies widely depending on severity, with mild cases often resulting in good recovery while severe cases can lead to persistent disability or death. Factors influencing prognosis include:
- The patient's age, with younger patients generally fare better
- Extent of axonal damage
- Presence of associated brain injuries
- Duration of coma
- Glasgow Coma Scale score at presentation
- Early access to comprehensive rehabilitation
Classification and Recovery
DAI is classified into three grades: Grade I has a relatively favorable outlook with many patients regaining consciousness within 24 hours and potentially achieving good functional recovery; Grade II carries a more guarded prognosis with longer periods of unconsciousness and variable recovery; Grade III is the most severe, often resulting in prolonged coma, significant disability, or death. Recovery typically follows a prolonged course over months to years, with most improvement occurring in the first 6 months.
Treatment and Management
Treatment focuses on preventing secondary injury through management of intracranial pressure, maintaining cerebral perfusion, preventing complications like infections and deep vein thrombosis, and implementing early rehabilitation including physical, occupational, speech, and cognitive therapies. Even patients with severe DAI can show surprising improvements over time due to neuroplasticity, though many will have permanent cognitive, behavioral, or physical impairments requiring long-term support. According to a recent study, prognostication of outcome from neurological disease has received much attention, and variables such as age, conscious level at presentation, physiological status, extent of brain injury identified by imaging, and the presence and severity of comorbidities have prognostic significance 1.
From the Research
Prognosis of Diffuse Axonal Injury
The prognosis of diffuse axonal injury (DAI) is a complex and multifaceted topic. Several studies have investigated the factors associated with mortality and outcome in patients with DAI.
- Factors associated with higher mortality in DAI patients include dysautonomia, hyperglycemia, and subdural hematoma 2.
- The severity of the lesion, classified based on the cerebral anatomical structures involved after the trauma, has a strong correlation with survival after DAI 3.
- Clinical factors with an important impact on prognosis in case of DAI are glycemia, early GCS, peripheral oxygen saturation, blood pressure, and time to recover consciousness 3.
- The DAI count, with a count of 6 or more being associated with poor outcome, is also a significant factor 2.
Outcome and Associated Risk Factors
The outcome of DAI patients can be assessed using various scales, including the Glasgow Outcome Scale (GOS) and the Extended Glasgow Outcome Scale (GOS-E).
- A study found that 30.8% of DAI patients had died, and 45.1% had shown full recovery according to the GOS-E at 6 months after trauma 4.
- The severity of DAI emerged as a risk factor for both mortality and dependence 4.
- Independent prognostic factors for functional outcome in DAI patients include age, pupillary reaction, Hb, DAI grading, and return of consciousness ≤7 days 5.
- Age is also an independent prognostic factor for health-related quality of life (HRQL) in DAI patients 5.
Long-Term Functional Outcome and Quality of Life
The long-term functional outcome and quality of life in DAI patients can be favorable, with more than half of patients having a favorable functional outcome and a good HRQL at long-term follow-up 5.
- A study found that 51% of DAI patients had a favorable outcome (GOSE 6-8) at long-term follow-up, with a median follow-up of 54 months 5.
- HRQL is a clinically relevant outcome measure because it reflects perceived outcome by patients, and 62% of DAI patients had a good HRQL after a median follow-up of 57 months 5.