Clinical characteristics

TBI diagnosis

Table 2 describes the main types of TBI identifiable in the NIHSI AA dataset.

Table 2: Description of type of TBI diagnoses used in this report
ICD-10-AM diagnosis ICD-10-AM code Condition description Primary diagnosis – Concussion Primary diagnosis –  Traumatic subarachnoid haemorrhage Primary diagnosis – Traumatic subdural haemorrhage Primary diagnosis – Other TBI Additional diagnosis – Concussion Additional diagnosis – Non-concussive TBI
Concussive injury S06.0 Brain injury caused by a blow to the head or violent shaking of the head. May be with or without loss of consciousness        
Traumatic subdural haemorrhage S06.5 Blood collects between the covering of the brain and the surface of the brain        
Traumatic subarachnoid haemorrhage S06.6 Bleeding between the arachnoid (the middle membrane surrounding the brain) and pia mater (the inner membrane surrounding the brain)        
Traumatic cerebral oedema S06.1

Swelling of the brain        
Diffuse brain injury S06.02 Wide area of brain tissue is affected        
Focal brain injury S06.03 Localised or limited brain tissue affected        
Epidural haemorrhage S06.04 Bleeding between the inside of the skull and the dura mater (the outer membrane surrounding the brain)        
Other intracranial injuries S06.08 Other intracranial injuries such as traumatic haemorrhage, haematoma or contusion        

Note that the ‘Principal diagnosis – Other TBIs’ and ‘Additional diagnosis – Non-concussive TBIs’ categories comprise different sets of conditions. This is because within the TBI as a principal diagnosis set, traumatic subarachnoid haemorrhage and traumatic subdural haemorrhage are reported separately, while within the TBI as additional diagnosis data, they are included in the ‘Additional diagnosis – Non-concussive TBI’ category, because the number of cases was very low.

For over 14,500 people (62%) in the cohort, the TBI was the principal diagnosis, meaning TBI was the main reason they were admitted to hospital (Figure 3; Table S1). The remainder of the cohort (38%) had TBI recorded as an additional diagnosis, alongside a different principal diagnosis that was the chief reason for hospital admission.

Concussion, with or without loss of consciousness, was the most common type of TBI diagnosis, representing 74% (17,250 cases) of initial TBI admissions.

Figure 3: Number of cohort patients by TBI diagnosis

This column graph shows that the TBI diagnosis categories with the most cohort patients were Principal diagnosis – Concussion (9,963) and Additional diagnosis – Concussion (7,293). The category with the least patients was Principal diagnosis – Traumatic subarachnoid haemorrhage (1,142).

Source: AIHW NIHSI AA v0.5.