Neuroscience Clerkship

CATEGORIES OF TRAUMATIC BRAIN INJURY

Patients who have sustained a traumatic brain injury (TBI) are often classified as mild, moderate or severe. This determination is based primarily on the Glasgow Coma Scale (GCS) along with other clinical and imaging information. This determination is useful in assessing the prognosis, and likelihood of long term sequelae.

Mild TBI

• GCS score > 12

• No abnormalities on CT scan

• No operative lesions

• Length of hospital stay less than 48 hours

• Brief loss of consciousness (LOC), usually seconds to minutes, and in some cases there is no LOC but simply a brief period of dazed consciousness.

These patients often have loss of memory for events immediately before or after the accident. Any focal neurologic deficits are transient and do not last longer than 30 minutes. Post-traumatic amnesia (PTA) does not last longer than 24 hours. Most patients make a complete recovery, although a small minority have persistent headaches, memory deficits, and mild difficulties with daily living activities that may last for months.

Moderate TBI

• GCS score of 9-12

• Length of hospital stay of at least 48 hours

• Usual LOC lasting from 30 minutes to 6 hours

Many of these patients have an operative intracranial lesion. Most are lethargic, stuporous and/or /combative. These patients are more likely to have long-term sequelae  (7% mortality; 66% permanent disability)

Severe TBI

• Initial GCS < 9

• Period of unconsciousness > 6 hours

Of these patients, 40% have a focal mass lesion on CT; there is a 36% mortality; and 100% of survivors have long-term disability