Clinical Practice Guideline
Developed for the
Aerospace Medical Association
by their constituent organization
Overview: Some element of
head injury occurs in over 70% of individuals involved in automobile accidents
and in at least 50% of all major trauma excluding burns. An estimated 80 to 90% of persons with head
injury have mild trauma. Of those
persons discharged with a good recovery from mild to moderate head injuries,
about 10% have a continuing need for medical care services as a result of their
head injury. The estimated prevalence in
The term "head injury" is a poor term that does not indicate the actual injury or risk of further problems. Head injury can be divided into the following categories:
Mild Head Injury: Injury without loss of consciousness, amnesia, or abnormality on examination, or head injury where unconsciousness has been less than 30 minutes and amnesia less than one hour.
Moderate Head Injury: Patients with a normal MRI or CT scan obtained within two days of injury and one or more of the following: unconsciousness of more than 30 minutes but less than 24 hours, amnesia of more than one hour but less than 24 hours, or a small epidural collection of blood found only on CT scan or MRI, without any evidence of parenchymal injury and followed to resolution without surgery.
Severe Head Injury: Head injury associated with one or more of the following: unconsciousness or amnesia or a combination of the two exceeding 24 hours duration, radiological evidence of retained metallic or bony fragments, leptomeningeal cyst, aerocele or arteriovenous fistula, depressed skull fracture with or without dural penetration, traumatic or surgical laceration or contusion of the dura mater or the brain or a history of penetrating brain injury, focal neurological signs, epidural, subdural, subarachnoid or intracerebral hematoma, CNS infection such as meningitis or abscess within six months of head injury, or CSF rhinorrhea or otorrhea lasting more than 7 days. It also includes head injury associated with one or more of the following: post-traumatic seizures, significant neurological deficits indicative of CNS parenchymal injury, evidence of impairment of higher CNS functions or personality, or CSF shunt.
Concerns: Closed head
injury is the most frequently encountered type of head injury in flyers. The decision to return an aviator to the
cockpit must be based on the probability of developing serious sequelae. The duration of unconsciousness is considered
an important predictive factor for post-traumatic epilepsy. It has been reported that if the duration of
unconsciousness exceeds 24 hours there is a 36% seizure incidence rate. To assess risk of residual brain damage from
closed head trauma, the symptom of most value is the duration of post-traumatic
The parts of the brain most vulnerable to damage are the frontal and temporal lobes. The cognitive tasks of judgment, memory, higher abstract reasoning, and mental flexibility are largely mediated by these parts of the brain. Mild intellectual deficits may be missed on a detailed neurological exam, and a good neuropsychological assessment combined with reports from perceptive relatives or friends may be the best tools for detection.
Medical Work-up: Acute management for head injury is in accordance with published ATLS protocol.
Aeromedical Disposition (military): Grounding and waiver criteria vary depending on the category of head injury under consideration and on the branch of service. Generally the following procedures are recommended:
Mild Head Injury. If there is no loss of consciousness and the physician neurological examination is normal, it is suitable to return to flying duties without a wait. If there was mild loss of consciousness or amnesia, the aviator needs a complete neurological examination by his or her physician, and at a minimum, neuropsychological screening within 30 days. If this screening is normal, the aviator may return to flying duties after a 30-day observation period. If abnormal, a local neurologic evaluation is required, to include an EEG and MRI. If these are normal a waiver for flying may be considered, but if abnormal an extensive neurological evaluation will be necessary. A history of seizure within five minutes of the injury (without recurrence) may be considered for waiver after a complete neurological evaluation.
Moderate Head Injury. Requires complete neurological evaluation by an internist or neurologist, CT scan within 48 hours and a routine MRI, EEGs (routine and sleep deprived), and an acceptable neuropsychological evaluation (Aviation Cognition Screen, MMPI, Halstead-Reitan, and WAIS-R). Examinees may be considered for return to aviation duties after six months if an early CT done within 48 hours was normal. Otherwise, the patient is considered for return to aviation duties in two years.
Severe Head Injury. Requires complete neurologic evaluation by a neurologist or internist, an early CT or MRI, and neuropsychological evaluation (tests as in moderate head injury). If the evaluations are normal, then a complete neurological evaluation is required which will also include a neuropsychological consultation (to include neuropsychological testing), and an EEG (routine and sleep deprived) and an MRI. Examinees may be considered for return to aviation duties after five years if all of the exams are normal. For individuals with post-traumatic seizures, significant neurological deficits, evidence of impairment of higher CNS functions, or a CSF shunt, a return to flying status is not recommended.
Disposition (civilian): In civil
aviation in the
Applicants with mild or moderate head injury and a seizure within the first week must have at least a two-year recovery off medications. If a seizure occurs beyond the first week or the airman suffered a severe head injury, the airman should be five years seizure free off medications prior to any consideration. If the airman had an intracerebral hemorrhage or brain contusion even though there have been no seizures, they are not considered for medical certification for five years. This is due to the increased likelihood of seizures in such circumstances.
Waiver Experience (military): There are currently 407 rated aviators in a military waiver file with the diagnosis of head injury. Of these, 44 were disqualified from flying duties. The majority of those disqualified were in the moderate and severe categories.
Waiver Experience (civilian): Return to aviation duties in the civilian community will be similar, but will be dependent on the type of rating the pilot has. As of the present writing there are no specific pathology codes for closed head injury.
Cooper PR (ed): Head
Injury, Third Edition.
Dambro MR, Griffith JA. Griffith’s 5 Minute Consult, Philadelphia, Williams and Wilkins. 1996; 134-5.
DeHart RL (ed): Fundamentals of Aerospace Medicine, 2nd edition, Baltimore, Williams & Wilkins, 1996: 635-37, 878-82.
Ernsting J, King P. Aviation Medicine, 2nd Edition, Boston, Butterworths and Co, Ltd. 1988; 645-7.
LeBlanc KE. Concussions in sports: Guidelines for return to competition, American Family Physician, 15 Sep 1994:50(4); 801-8.
McLaurin RL (ed): Head Injuries--Second Symposium on Neural Trauma.
Rapoport AM, Sheftell FD. Headache Disorders, A Management Guide For Practitioners, Philadelphia, WB Saunders and Co. 1996; 29.
Rayman, RB, Clinical Aviation Medicine, 3rd edition, Castle Connolly Graduate Medical Publishing, LLC, 2000, pp. 65-69.
Rizzo M and Tranel D (eds): Head Injury and Post concussive Syndrome.