Irish Institute of Clinical Neuroscience 14th Annual Neurology Update Meeting

The IICN 2016 Annual Neurology Update Meeting took place on 14 October in the RDS, Ballsbridge, Dublin. The theme for this year’s meeting was ‘Hot Topics in Neurology’. James Fogarty reports

Identifying concussion in sports competition ‘remains difficult’ 

-field diagnosis of concussion remains difficult and equestrian brain injuries are the biggest sports-related category, the recent Irish Institute of Clinical Neuroscience (IICN) Neurology Update Meeting heard.

Neurosurgeon Ms Catherine Moran, Beaumont Hospital, Dublin, gave a detailed presentation on neuro-trauma in sport and discussed how she and her colleagues see the severe end of sports-related head trauma injuries.

 “The vast majority of head trauma is mild and there is more awareness and research into concussion,” she told the meeting. As data on trauma in sport is lacking in Ireland, Ms Moran discussed US figures from level 1 and 2 trauma centres for adults aged over 18 years and included moderate-to-severe cases. The data, which covered a 10-year period, recorded 350,000 traumatic brain injuries (TBIs) in adults.

“We know that sport contributes to head injuries in only less than 2 per cent, so that equates to 4,788 [TBIs] due to sports.”

The type of sports the data classified included equestrian, fall or interpersonal contact, which included all pitch sports, such as American football, rugby, skiing and snowboarding, etc. Overall, the vast majority, 85 per cent, were mild head injuries, 3 per cent were moderate, but 10 per cent were severe. Most of these were found in the 18-29 years age group. In total, 144 deaths occurred as a result of TBI in sport, with a corresponding mortality rate of 3 per cent for sports-related TBI.

Across the sports categories analysed, several important trends emerged. Equestrian and related sports were the largest contributor to sports-related TBIs in adults and accounted for more than 50 per cent of all TBIs in those older than 40 years. Helmet usage in these sports was just 25 per cent, “a pretty shocking” figure, said Ms Moran.

In the sports falls and interpersonal contact category, the younger age group again had a higher incidence but the mortality rate, at 2.3 per cent, was lower. Roller sports had a 4.1 per cent rate; skiing and snowboarding 2.1 per cent; while aquatic sports had a 7 per cent rate.

“This was the worst prognostic in terms of sports category. Presumably the patient had also suffered an anoxic injury at the time of their TBI,” she told the meeting.

Concussion

Ms Moran also discussed the issue of how a clinician determines whether an injury is a concussion or worse: “You don’t have the CT scanner at the side of the pitch.”

On-field diagnosis of concussion, defined as an immediate and transient impairment of neural function, such as an alteration in consciousness, disturbance in vision and equilibrium, remains a challenge. Only 10 per cent are associated with a loss of consciousness and up to 10 per cent may remain asymptomatic for the first two days.

Diagnosis is heavily reliant on a clinical evaluation. While work is being carried out regarding identifying enzymes in saliva, nothing has been proven to work so far, said Ms Moran.

On the sidelines, the sports concussion assessment tool (SCAT) is used by both the Olympics and the US National Football League.

“So when do we get worried?” she asked, adding that any of the following symptoms warrants consideration of activating emergency procedures and urgent transportation to the nearest hospital:

Glasgow Coma Score (GCS) of less than 15.

Deteriorating mental status.

A potential spinal injury.

Any progressive or worsening symptoms.

“Simply, people with a worsening headache should be brought to a hospital,” she added. Patients, even those with a GCS of 15, with a severe headache, vomiting, loss of consciousness or post-traumatic amnesia, should also be brought to hospital.

Subdural haematomas are much more common in all traumas but in sport, they account for 60 per cent of all acute post-traumatic haematomas and the majority of the lethal brain injuries in both organised and recreational athletic activities. They are also twice as common after falls

Head injuries

Head injuries, which are divided into primary and secondary, are classified into five different types:

Skull injuries.

Focal injuries.

Diffuse injuries.

Penetrating.

Blast.

Regarding skull fractures, she explained that these can be either closed or opened and the majority are frontal parietal.

“The main issue with skull fractures is to be careful of mid-line skull fractures that overlie the sagittal sinus and we tend to treat them more conservatively, as you can tear the sagittal sinus fixing it and have a catastrophic haemorrhage.”

Traumatic cerebrospinal fluid (CSF) fistulae can appear early, within one week and the majority, 70 per cent, resolve without treatment within seven days. Furthermore, unlike otorrhoea, which almost never returns, rhinorrhoea can reoccur after healing, Ms Moran said.

A 1997 meta-analysis on whether or not these patients should be started with antibiotic prophylaxis found that only 2.5 per cent of people who received antibiotics, versus 10 per cent who did not, developed basal meningitis, she reported.

Focal injuries, which are concentrated in one region of the brain as a result to a severe blow to the head, can be very challenging.

“One of the most frightening is the epidural haematoma, where you have no primary injury,” said Ms Moran. “That’s the one pathology that you’re always worried about.”

Regarding a middle meningeal artery tear, it is not a common complication of head injuries.

However, while it only accounts for 2 per cent of admissions, it is responsible for between 5-to-15 per cent of fatalities.

“If you can get them fast, you can save them,” she said, but identifying these patients can be difficult.

The lucid interval only happens in 14-to-21 per cent of patients and only 20 per cent of patients with an epidural haematoma will have a loss of consciousness. Furthermore, up to 44 per cent are unconscious from the time of injury but 28 per cent regain consciousness after coma.

Subdural haematomas are much more common in all traumas but in sport, they account for 60 per cent of all acute post-traumatic haematomas and the majority of the lethal brain injuries in both organised and recreational athletic activities. They are also twice as common after falls.

“Often, a venous vascular injury [occurs] in older people; in younger people it can be a small cortical artery that’s bleeding. They often have a co-existing diffuse axonal injury, so they have poorer outcomes than the epidural haematoma,” said Ms Moran. These patients often have a lower GCS at impact than an epidural haematoma, she added.

Diffuse injuries, including concussion and diffuse axonal injury, can have one of the worst prognoses for head injuries. Diffuse axonal injury results from severe angulation or rotational acceleration, shear and terrible forces on axons.

These patients would be anticipated to deteriorate from day five to 10. They would undergo intracranial pressure (ICP) monitoring and possibly require decompressive craniotomy, depending on the ICP.

She added that the RESCUEicp trial examined the value of a decompressive craniotomy post-injury. It found that the surgical group had a lower mortality rate of almost half but a much poorer Glasgow outcome score.

“They haven’t given a recommendation with the paper. The decision rests with each case. The two main factors of whether or not you perform a decompressive craniotomy when the ICP is uncontrollable is age and their initial GCS, which is often very difficult to find out.”

In paediatric head injury, fracture deformity is between 1.7 and five times greater than in adults due to increases in deformability. There is also a greater propensity for epidural haematomas and diffuse injury.

Second Impact Syndrome, which was first described in 1984, occurs when an athlete who sustains a head injury — often a concussion or greater injury, such as contusion — sustains a second head injury before the symptoms associated with the first have cleared.

The pathophysiology is thought to involve a loss of auto regulation of the brain’s blood supply, oedema and uncontrolled intracranial hypertension.

“This can lead to uncal herniation and cerebellar herniation and death in seconds.”

Between 1980 and 1993, there were 35 probable cases among American footballers alone, 17 of which were confirmed at autopsy and 10 of which were most likely, Ms Moran reported.

Returning to play

Following a head injury, the common question of whether a player can return to activity can be difficult to answer, she said.

“One of the questions we get asked a lot in paediatric outpatients is, ‘can my son play rugby?’ He’s got an incidental finding of something else. The ‘something else’ is most often an arachnoid cyst.”

A systemic review of TBIs associated with arachnoid cysts found that they tended to be chronic presentations after 25 days or so, with haemorrhaging into the cyst. But there was no clear counter indication to participate in sports. However, it advised that parents and children should be counselled.

Regarding an abnormal scan, Ms Moran said that refraining from contact sport has been recommended in patients who harbour CM-I with associated syringomyelia, obliteration of the subarachnoid space, or indentation of the anterior space, or indentation of the anterior medulla.

Additionally, the presence of CM-I that is symptomatic should contraindicate participation in contact or collision sport.