From the Guidelines
The prognosis of diffuse axonal injury (DAI) is highly variable, with severe cases carrying a high mortality rate and survivors often experiencing significant long-term disabilities, as reported in a recent study 1. The prognosis of DAI varies widely depending on severity, with mild cases often resulting in good recovery while severe cases may lead to persistent disability or death.
- Patients with mild DAI typically experience full recovery within weeks to months,
- while moderate cases may have lasting cognitive or physical impairments but can still achieve functional independence. Severe DAI carries the worst prognosis, with high mortality rates and survivors often experiencing significant long-term disabilities including cognitive deficits, motor impairments, and behavioral changes. Recovery follows a predictable pattern, with most improvement occurring in the first 6 months post-injury, though some patients continue to show progress for 1-2 years. Age significantly impacts outcomes, with younger patients generally showing better recovery potential due to greater neuroplasticity, as noted in a study on traumatic brain injury 1. Early rehabilitation including physical, occupational, and speech therapy is crucial for optimizing outcomes, as emphasized in a consensus statement from stakeholder professional organizations 1. The diffuse nature of DAI, involving widespread disruption of axonal connections throughout the brain, explains why recovery is often prolonged and incomplete compared to more localized brain injuries. It is essential to consider the patient's overall health and potential for recovery when making decisions about their care, taking into account the latest guidelines and recommendations from reputable sources 1.
From the Research
Prognosis of Diffuse Axonal Injury (DAI)
The prognosis of DAI is generally poor, with high mortality and morbidity rates 2. Several factors have been identified as associated with higher mortality and poor outcome, including:
- Dysautonomia, hyperglycemia, and subdural hematoma 3
- DAI count ≥ 6 3
- Glasgow Coma Scale score < 8 3, 4
- Secondary systemic injuries score ≥ 3 3
- Transfusion need 3, 5
- Hypotension on admission 5
- DAI Stage III 5
Outcome Prediction Models
Several outcome prediction models have been studied for their efficacy in predicting mortality and unfavorable outcomes in DAI patients, including:
- Glasgow Coma Scale (GCS) 4
- Trauma and Injury Severity Scoring system (TRISS) 4
- New Trauma and Injury Severity Scoring system (NTRISS) 4
- Abbreviated Injury Scale (AIS)/head 4
- Corticosteroid Randomization After Significant Head Injury (CRASH) 4
- International Mission on Prognosis and Analysis of Clinical Trials (IMPACT) 4 These models have shown varying degrees of discrimination and calibration in predicting outcomes, with the IMPACT model showing statistically perfect calibration for both 6-month outcome variables 4.
Clinical Features and Outcomes
DAI can be classified into three grades, each with different outcomes 2:
- Grade I: axonal lesions in the cerebral hemispheres
- Grade II: focal axonal lesions in the corpus callosum
- Grade III: focal or multiple axonal lesions in the brainstem Pure DAI (without associated injuries) and non-pure DAI (with associated injuries) have been compared, with no significant difference in demographic data and clinical findings on admission 5. However, DAI Stage III was independently associated with poor outcome when compared to Stage I or I and II 5.