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Three Part Question

In [patients following minor head injury] what [combination of clinical variables] predicts [the development of long term disabilities] ?

Clinical Scenario

A 45 year old woman is admitted to the emergency department with a minor head injury after being involved in a road traffic accident. She had a GCS of 14 in the ambulance and had a witnessed loss of consciousness of around 10 minutes at the scene. However she now has a normal GCS, a mild headache but no other clinical symptoms or signs. All investigations are normal and you are about to send her home. However she is worried about her headache and tells you that she had a friend who was 'never right again' after a head injury 2 years ago. You wonder whether she should be followed up but you don't know which patients are at high risk of long term disabilities such as headache, dizziness, or symptoms classed as post-concussional syndrome.

Search Strategy

Medline 1966-10/03 using the OVID interface.
[exp post concussion syndrome/ OR disability.mp OR consussi$.mp OR postconcussion.mp OR post-concussive.mp OR sequelae.mp] AND [exp craniocerebral trauma/ OR exp brain injuries/ OR head inj$.mp] AND [minor.mp OR mild.mp] AND Maximally sensitive RCT filter. LIMIT to human AND English.

Search Outcome

Altogether 200 papers were found of which 5 were relevant to our search. The 5 papers are listed in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Rimel RW et al, 1981 USA	538 adults and children who had sustained minor head injury (defined as GCS 13-15, LOC <20min and 48hrs admission or less) admitted to a single hospital. 424 patients were evaluated 3 months following injury(Assessment of subjective complaints, employment status, neurological examination, psychological assessment for estimating life stress, and 133 patients also underwent a neuropsychological test battery (69 of these were evaluated, that did not differ statistically from the total study population in terms of sex, education and employment)	Prospective Observational Cohort Study	Clinical variables regarding pre-morbid status, symptoms on admission and symptoms at 3 months.	At 3 months:78% complained of persistent headaches. 59% had memory deficits. 34% of previously employed were now unemployed. Most patients showed mild neuropsychological impairment on the Halstead-Reitan test (which assesses, attention, concentration, memory and judgement). Pre-morbid factors of significance that influence return to work included age, education employment, income and socio-economic status. Only 6 out 424 were involved in litigation. Only 1 out of 6 did not return to work.	No control group was used. 79% were successfully followed up. 27 patients only had a telephone interview as F/U Only 69 patients underwent the neuropsychological test battery.
Bazarian JJ et al, 1999, USA	71 minor head injury (MHI) patients and 60 orthopaedic controls. MHI defined as GCS 15, LOC <10min, no skull fracture or focal neurology, and no brain injury on CT, if done. Excluded if intoxicated) All patients answered several neurobehavioural tests in emergency department within 24 hrs of minor head injury. All 131 patients in the study group were followed up by phone at 1, 3 and 6 months post injury to determine if they met the DSMIV criteria for postconcussive syndrome	Prospective Case Control Study	Clinical variables regarding pre-morbid status, symptoms on admission and symptoms at 3 months.	Incidence of postconcussive syndrome at 1 month was 58% at 3 months was 43%at 6 months was 25%.Incidence of PCS was less in those injured during sports (may reflect less brain injury compared to those suffering RTA) and in those who had a shorter duration of LOC. PCS predictors at 1 month:Presence of anterograde and retrograde amnesia Sensitivity 5% Specificity 79%. Digit Span Forward Score < 8Sensitivity 47.5% Specificity 82.8% Hopkins Verbal Learning A Score <26Sensitivity 80% Specificity 51.7%. PCS predictors at 3 months:Digit Span Forward Score <8Sensitivity 53.3% Specificity 74.4%. No variables predicted PCS at 6months.	No variable or combination of variables could predict developing Post concussive syndrome at 6 months. No power study was presented for multivariate analysis and this study is clearly underpowered for this type of analysis. i.e. only 16 patients had PCS at 6 months.
Thornhill S et al, 2000, Scotland	2962 adults with head injury admitted to five hospitals in Glasgow. Patients were stratified according to the GCS as mild, moderate and severe. 549 (71%) of the 769 patients selected for follow-up 1 year after injury participated	Prospective Case Control Study	To determine the incidence of disability in patients admitted to hospital with a head injury.	GOS at 1 year:20% of mild head injuries had severe disability,27% had moderate disability	No variable or combination of variables could predict developing Post concussive syndrome at 6 months.No power study was presented for multivariate analysis and this study is clearly underpowered for this type of analysis. i.e. only 16 patients had PCS at 6 months. In Hospital data was collected by retrospective case note review and follow up was by telephone or postal questionnaires.35% of disabled patients after Minor Head injury had no positive clinical predictors that could have predicted their poor outcome
			Disability measured by the Glasgow Outcome score(GOS)	Survival with moderate or severe disability was common after mild injury (47%) and similar to that after moderate (45%) or severe injury (48%). Only 47% of disabled survivors were seen again in hospital after discharge, and only 27% received any rehabilitation. A multivariate logistic regression analysis restricted to patients who were mildly injured identified age>40 yrs, pre-existing physical limitation and a documented history of brain illness as independent predictors of disability at 1 year.
Bazarian JJ et al, 2001, USA	83 adults presenting with minor head injury. (GCS=15, LOC<10min, no skull fracture, no focal neurology, no brain injury on CT, not intoxicated) Clinical, demographic data and the results of a neurobehavioural test battery were collected for all patients. 69 patients (83%) replied to a validated telephone questionnaire at 1 month after initial presentation. Only 40 (58%) met the study definition of PCS at 1 month	Prospective Observational Cohort Study	To identify minor traumatic brain injury patients at low and high risk of PCS by comparing the predictive values of variables generated by logistic regression and recursive partitioning	58% of patients followed up, had PCS at 1 month after initial presentation. Low Risk Group:PCS occurred in 9% of men scoring >24 on the Hopkins Verbal Learning A (HVLA) and in 9% of those injured in sports scoring >22 on HVLA. High Risk Group:PCS occurred in 89% of women scoring <9 on the Digit Span Test and in 92% of those injured via falls or MVA scoring <11.5 on HVLB2.	Of the 83 patients originally enrolled, only 69 were followed up at 1 month. This study is vastly underpowered for recursive partitioning No Power study was presented Results not validated. Out of 69 patient, 11 were classed as low risk, 24 as high risk and 34 or half of the study group fell into a moderate risk category therefore severely limiting the usefulness of this decision rule.
Haboubi NH et al, 2001, UK	1255 patients aged 16-65 yrs admitted to hospital with minor head injury (GCS 13-15, admitted for less than 48hrs) were invited to attend a head injury clinic Of those only 639 patients attended at 2 weeks and only 179 at 6 weeks following minor head injury	Retrospective Cohort Study	To address the problem of follow-up of patients after minor head injury	Percentage of patients who had persisting symptom at 2 weeks :Headache 35%Fatigue 33%Sleep problems 47%. Memory loss 46%. 219 of attendees (56%) were unable to return to work 2 weeks after discharge. Out of 179 attendees of a second assessment 6 weeks after the injury, 49 patients were still off work. 43% of attendees had history of alcohol intake prior to injury.	No attempt was made to see how prevalent these symptoms were either in the general public or in these patients prior to injury. High drop-out rate in head injury clinic attendance. No combination of clinical factors at injury could predict poor outcome.

Comment(s)

2 papers by Bazarian et al attempted to construct a clincial decision rule that could predict post-concussive syndrome. However the rule, which was derived on a very small number of patients, performs poorly and 50% of patients could not be classed as either low or high risk. The remaining papers were unable to derive a rule to identify high risk patients. More alarmingly, all papers reported that the incidence of disability post minor head injury was high. Reports of 70% headaches at 3 months and moderate or poor Glasgow outcome scores of 47% at 1 year were presented. Therefore although there is no reliable way to identify those at high risk of disability on the initial clinical assessment, many patients will suffer significant sequelae following their head injury. Interestingly Haboubi et al reported the results of a minor head injury clinic, and found that although disability rates were still high, of 1255 patients offered follow up, only 179 attended at 6 weeks.

Clinical Bottom Line

The Incidence of Disability following minor head injury is high but there are no reliable combinations of clinical factors that will predict patients who go on to suffer these complications.

References

1. Rimel RW, Giordani B, Barth JT, et al. Disability caused by minor head injury. Neurosurgery 1981;9(3):221-228.
2. Bazarian JJ, Wong T, Harris M, et al. Epidemiology and predictors of post-concussive syndrome after minor head injury in an emergency population. Brain Inj 1999;13(3):173-189.
3. Thornhill S, Teadsdale GM, Murray GD, et al. Disability in young people and adults one year after head injury: prospective cohort study. BMJ 2000;320(7250):1631-1635.
4. Bazarian JJ, Atabaki S. Predicting postconcussion syndrome after minor traumatic brain injury. Acad Emerg Med 2001;8(8):788-795.
5. Haboubi NH, Long J, Koshy M et al. Short-term sequelae of minor head injury (6 years experience of minor head injury clinic). Disabil Rehabil 2001;23(14):635-638.