1. Diffuse axonal injuryDr John HellConsultant neuroanaesthetist andneurointensivist

2. Prevalence Probably present even in concussion Present in 72% of TBI survivors withGCS 3-13 (moderate-severe TBI) Combined with haematomas/contusions in50% 3. Mechanism Severe acceleration of brain in skull Differing density of grey & white mattercauses shearing of axons Lateral & rotational impacts especially No absorption of force by facial or skullfractures 4. Pathophysiology Axonal shearing Stretching of axons primary brain injury Swelling & rupture of axons Biochemical changes & release of mediators Cerebral oedema causing raised ICP &restriction of diffusion Secondary brain injury from hypoxia &relative hypotension (CPP) 5. Radiology Poorly seen on initial CT better later Better seen on MRI Graded according to increasing severity: 1: only lobar white matter grey/white 2: lesions of corpus callosum 3: dorsolateral brainstem negativeprognostic sign 6. Management Initial resuscitation to normal parameters Keep everything normal Maintain venous drainage Adequate sedation Avoid hyperventilation acutely Expect cerebral oedema to develop ICP monitor maintain CPP 7. Prognosis Death Disability unpredictable nature & severity Brainstem involvement worse Young better (but not children) Better connectivity better outcome Poor initial GCS worse outcome Complicated by hydrocephalus/infection worse Can recover to very good quality of life 8. Diffuse axonal injury Suspect from mechanism Resuscitate to normal parameters Expect to swell ICP bolt Avoid hyperventilation unless ICP raised Diagnose on repeat CT or MRI Aggressive TBI management of ICP All outcomes possible