Mild Traumatic Brain Injury: An Update for Advanced Practice Nurses

Esther Bay, PhD APRN BC CCRN; Samuel A. McLean, MD MPH

Disclosures

J Neurosci Nurs. 2007;39(1):43-51. 

In This Article

Classification and Screening for MBI

There is ongoing debate about the best screening and method for classifying patients with MBI. TBI classification is traditionally based on the Glasgow Coma Scale (GCS) score at the scene of the crash or in the ED. Initially, the GCS score was intended to establish coma severity and predict future treatment and outcomes (Teasdale & Jennett, 1974). However, there is now considerable debate about its sensitivity and specificity. A consensus is developing that the motor component subscale alone is sufficiently valid in predicting neurological outcomes (Gill, Windenmuth, Steele, & Green, 2005; Healey et al., 2003; Ross, Leipold, & Terregino, 1998).

Other healthcare experts propose modifications of the GCS with enhanced sensitivity for people with mild injuries, such as the GCS-Extended (GCSE) or the GCS 15 (Batchelor & McGuiness, 2002; Nell, Phil, Yates, & Kruger, 2000). The GCS-E was proposed to extend the GCS data for patients with milder injuries by adding a scale to define the degree of posttraumatic amnesia (PTA) experienced by the injured person. The amnesia subscale is rated 0-7 and reflects amnesia from greater than 3 months (scored 0) to no amnesia (scored 7).

Batchelor and McGuiness (2002) proposed that those with a GCS score of 15 have three MBI risk categories based on computed tomography (CT) scan results and symptom clusters. Risk levels are as follows for those with a GCS score of 15 and the following characteristics:

  • Low risk: no symptoms or previous symptoms of dizziness, headache, or vomiting

  • Intermediate risk: reports of loss of consciousness or posttraumatic amnesia

  • High risk: severe headache, persistent nausea or more than one vomit.

A management protocol is provided for patients in the high-risk category that includes performing a head CT scan and 1-2 days of hospital monitoring followed by home observation (Fabbri et al., 2004).

Despite these proposed models and the understanding that the GCS lacks sensitivity in regard to MBI, clinical practice guidelines continue to support use of the GCS. This suggests that rigorous studies examining the most sensitive measure for detecting MBI are inadequate (National Institute for Clinical Excellence, 2003).

In 2001, a workgroup of MBI experts convened by the CDC reported on appropriate and feasible methods for assessing the incidence and prevalence of MBI in the United States. One outcome of this report was the development of screening criteria that could be used prospectively or retrospectively (CDC, 2003). Using the CDC MBI Screening Tool, determination of MBI could be gathered from chart review, interviews, surveys, or healthcare data sets ( Table 2 ). However, validity and reliability of this tool has yet to be established.

To detect hidden or obvious MBI, screening begins with a direct query about head injury symptoms experienced at the time of the injury or shortly thereafter, a thorough health history, and a comprehensive physical exam. Specific preinjury information known to contribute to postinjury morbidity should be obtained because, it is proposed, those patients with significant preinjury risk factors may benefit from more intensive rehabilitation (Ghaffar, McCullagh, Ouchterlony, & Feinstein, 2006). This includes determining the preinjury presence of psychiatric history, substance abuse, or preinjury social difficulties.

In the following example, Mary, a 35-year-old mother of three, was involved in a motor vehicle crash on her way home from taking her children to school. She refused transport to the hospital, stating that she would go home, rest to "settle her nerves," and then go out to pick up her kids from school. However, the paramedic report indicated she was shaken and dazed at the scene. Over the next month, as she continued her normal routine, her husband became alarmed about the following changes: she was more irritable with the kids and often yelled that they were too noisy, she had difficulty sleeping, her checkbook logging became erratic and erroneous, and she was careless about cooking safely or maintaining home security. She visited her healthcare provider for complaints of headache and irritability. Her physician questioned Mary about the accident and determined that she may have sustained an MBI. Referrals were made to a neurologist who proceeded with appropriate neuropsychological testing, especially because of her prior history of dysthymia. After the diagnosis was supported and baseline data about deficits gathered, outpatient rehabilitation therapies were initiated. This typifies the nontraditional means of entering the healthcare system and the retrospective data gathering about symptoms of MBI.

The presence of premorbid disorders may be associated with postinjury morbidity, although results from various studies lack full agreement (Dikmen, Bombardier, Machamer, Fann, & Temkin, 2004; Jorge et al., 2004; Levin et al., 2001; Moldover, Goldberg, & Prout, 2004). Turner, Kivlahan, Rimmele, and Bombardier (2006) were unable to confirm that patterns of excessive alcohol use contributed to cognitive difficulty after head trauma. Rather, cognitive difficulties were attributed to the severity of the injury. Other experts reported that persons with TBI who are older, have increased preinjury social difficulties, or had a preinjury psychiatric disorder were more likely to have postinjury psychological or physical morbidity (Bay, Kirsch, & Gillespie, 2004; Breed, Flanagan, & Watson, 2004; Fenton, McClelland, Montgomery, MacFlynn, & Rutherford, 1993; Jorge et al., 2004). Thus, obtaining a thorough and specific health history in identifying those at risk for TBI morbidity is critical.

Some experts distinguish complicated from uncomplicated MBI (Borgaro, Prigatano, Kwasnica, & Rexer, 2003; Williams, Levin, & Eisenberg, 1990). Patients classified with complicated MBI meet the criteria for MBI and also have intracranial lesions on MRI or focal neurological deficits such as hemiparesis or aphasia (CDC, 2003; Williams et al., 1990). Patients classified as having uncomplicated MBI are without demonstrable structure change or deficits. Those with complicated MBI have greater cognitive dysfunction than those with uncomplicated MBI, but do not differ on manifestations of mood disorder (Borgaro et al., 2003).

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