Trauma to the Brain

59 Trauma to the Brain



Traumatic brain injury (TBI), occurring worldwide in relation to various types of civilian and armed forces accidents, is one of the most common mechanisms for serious lifelong morbidity or mortality. Within the United States, one person sustains a head injury every 15 seconds. The societal loss is devastating as the majority of these injuries involve individuals entering adulthood with great promise only to be cut down, often with irretrievable injuries that leave them dependent for their remaining lives. For example, within the United States there are 2 million cases of traumatic head injury annually; 100,000 die within hours, 500,000 require hospital stays, and up to 100,000 have permanent disability. Whether it is a cycling, skiing, or relatively uncommon contact sports injury, or result of an impulsive acceleration while negotiating a challenging roadway to impress peers with one’s driving prowess, or on a battlefield such as currently occurs in Iraq or Afghanistan, the consequences are the same: a very promising or accomplished life has lost all its future potential. Various head injury classification systems exist. These include (1) severity (mild, moderate, severe), mechanism (closed vs. penetrating), (2) skull fractures (depressed vs. nondepressed), (3) presence of intracranial lesions (focal vs. diffuse), and (4) hemorrhages, that is, extra-axillary epidural or subdural, subarachnoid, or focal parenchymatous lobar, or brainstem Duret hemorrhage.



Clinical Vignette


An otolaryngologist requested an expeditious neurologic evaluation of a very vigorous octogenarian who was so fit that he downhill skied 3 weeks earlier; this patient reported recent-onset sense of “spinning vertigo” and cloudiness of vision, precipitated by sudden standing or neck extension. Additionally, he was experiencing new-onset headaches that were becoming increasingly severe and were awakening him from his sleep. Concomitantly he was having difficulty with mental concentration and hand coordination, as well as a feeling of “weak legs.” On further questioning, he recalled that 7 weeks earlier he had slipped on the ice, striking his occiput, while helping to push an auto out of a snow bank.


On examination, he had moderately severe difficulty performing tandem gait (something most healthy 70-year-olds often cannot perform, but this was probably abnormal in this athletic man). The remainder of his neurologic examination was normal. Head computed tomography (CT) demonstrated large biparietal subdural hematomas. Bilateral craniotomies were performed, draining both hematomas. Except for a few focal motor sensory seizures, occurring only in the immediate postoperative period and responding well to phenytoin, his recovery was otherwise excellent.


Comment: This gentleman presented a classic history for subdural hematoma. Initially he had disregarded a moderately significant closed head injury as there were no immediate sequelae other than for a modest scalp contusion. He was symptom-free for 5 weeks. This patient’s initial symptoms were not very impressive because his brain compensated well. Despite a careful neurologic examination, the tandem ataxia was his only neurologic abnormality. This could easily be dismissed as appropriate for age; however, the entire clinical picture was classic for a subdural hematoma until proven otherwise as defined by the CT scans.



General Principles of Head Injury Care


The initial management of severe head injuries, as for any serious trauma victim, includes the “ABC” evaluation for Airway, Breathing, and Circulation and a careful general and neurologic examination.





Concomitantly, the patient’s general level of responsiveness must be assessed using the Glasgow Coma Scale (Fig. 59-1). The lowest possible score of 3 means that individuals have no ability to open the eyes, no motor response to verbal command or direct stimuli, and no verbal response to the physician’s questions, giving a score of 1 or nil for each of the three components. The highest possible score is 15. Soft tissue injuries are commonly associated with more severe head injuries. A complete examination of the exterior surface of the face and head is vital. Blood loss can be extensive given the location of blood vessels within the dense connective tissue of the scalp, which decreases retraction of cut vessels and promotes bleeding.





Extra-Axial Traumatic Brain Injuries




Epidural Hematomas


These represent an acute blood collection contained between the dura and inner table of the skull. These occur in approximately 2% of TBIs (Fig. 59-5). Epidural hematomas (EHs) most commonly develop in the temporal and parietal regions; 90% of EH are associated with a skull fracture. Arterial lacerations, particularly of the middle meningeal artery (Fig. 59-6) or, less commonly, venous injuries, initiate the formation of hematomas. Contiguous lacerations of the dura mater allow this blood into the epidural space.




Immediately after the closed head injury, the patient “typically” experiences an initial but relatively brief loss of consciousness secondary to the primary concussive injury. This is then followed by a lucid interval with return of wakefulness. Subsequently, as the torn vessels leak, an epidural hematoma develops and enlarges, leading to a rapid lapse into coma. Sometimes this entire process may transpire from injury, to transient loss of consciousness, and to a brief period of a “paradoxically reassuring alertness,” only to have a devastating, often irreversible, coma develop within just 1 hour after the blunt head injury (see Fig. 59-3). However, this classic presentation occurs in less than one third of affected individuals. The actual rate of symptom progression depends on the type of associated brain injuries, their etiology, and the subsequent precise rate of blood accumulation within the epidural space.


Cranial CT imaging usually demonstrates a hyperdense, biconvex collection between the skull and brain (Fig. 59-7). On occasion, the initial CT is normal as the hematoma has yet to develop to a size that is definable. Thus when the patient is “at risk,” it is essential to be prepared to repeat the CT scan at the slightest change in clinical status. Once the EH is identified, emergency surgical evacuation is indicated. Any failure to recognize an epidural hematoma has a most significant mortality depending on patient age, time of treatment, hematoma size, and associated injuries.



Jun 4, 2016 | Posted by in NEUROLOGY | Comments Off on Trauma to the Brain

Full access? Get Clinical Tree

Get Clinical Tree app for offline access