Head Injury


Presentation

The following symptomatology is found in patients suffering in traumatic head injuries:

  • General Appearance: Patients are usually brought to the emergency room with loss of consciousness due to severe brain trauma. Less severe cases can present with confusion, drowsiness and disorientation. 
  • Head and neck: Headache and nausea is a usual symptom of increased intracranial pressure. Vision is usually blurred with tinnitus of the ear due to cranial nerve damage. 
  • Chest and heart: Tachyarrhythmia may be caused by secondary subarachnoid bleeding due to traumatic brain injury.
  • Abdomen: Intractable vomiting may be an outward sign of nausea. 
  • Extremities: Spasticity and rigidity of all four extremities may be evident during significant cerebral and cerebellar injuries.
  • Neurologic: Patients may present with dizziness and loss of balance due to cranial nerve impairment or damage to the middle ear. 

Workup

A comprehensive clinical history and a thorough physical and neurologic examination may be all that is needed to diagnose traumatic head injuries. The following laboratories and tests may be helpful in the diagnosis and management of the traumatic brain injuries:

  • Glasgow Coma Scale: A 15 point scale that determines the level of consciousness of patients with head injury
  • Intracranial monitoring device: Inserted in the skull to monitor the actual intracranial pressure
  • Imaging: Computerized tomography can easily visualize skull fractures, intracranial bleeding, brain contusions, brain swelling and hematoma formation. Magnetic resonance imaging can demonstrate a more detailed view of the brain structures.

Treatment

Mild traumatic head injury may not require any treatment. Patients are usually advised adequate rests and may be given pain relievers to treat symptoms of headache. However, patients sustaining severe head injuries with altered state of consciousness and unstable vital signs may need immediate emergency care.

Medical management with osmotic diuretics and anti-seizure drugs may be given to allay the symptoms of severe traumatic head injury. Medical decompression of the CSF using mannitol and vasopressors can maintain cerebral perfusion pressures to at least 70 mmHg ensuring undisrupted blood supply to important cortical structures [10].

Neurosurgical approaches to traumatic head injury include craniotomy and the removal of hematoma, primary repair of skull fractures, or burr hole craniotomy to relieve the pressure in the brain. Rehabilitation treatment with physiatrists, occupational therapists and neuropsychologists are an essential part of post-hospital and post-surgical care of patients.

Prognosis

In general, traumatic head injury prognosis worsens with the relative increase and extent of brain injury. Patients presenting at a Glasgow Coma Score (GCS) of 3 within the first 24 hours carries a 65% mortality rate [8]. The presence of subdural hematoma in patients with head injury varies inversely with the GCS score in terms of prognostic outcome and mortality rate [9]. The clinical condition of patients whether they are conscious and coherent or whether they are in a vegetative state may correlate closely with their prognosis.

Complications

Many complications can occur immediately or a few minutes after the traumatic head injury. The severity of the head injury increases the risk for permanent brain complications and more severe brain complications. The following complications are seen in patients suffering from traumatic head injuries:

  • Altered state of consciousness
  • Seizures or traumatic epilepsy
  • Brain swelling
  • Meningitis 
  • Cerebral vascular damage
  • Neuropathies
  • Intellectual problems
  • Communication difficulties
  • Degenerative brain disorders

Etiology

The following common events may result in traumatic brain injury among patients:

  • Falls: This is the most cause on traumatic head injury in young adults and older patients. This includes falling in a flight of stairs, falling from a ladder, and slipping in a bath. 
  • Vehicular accidents: This usually involves pedestrians colliding with motorcycling, bicycle, and automobiles. 
  • Armed conflict: Domestic violence like gunshot wounds to the head represents 20% of all traumatic head injuries. 
  • Sports injuries: Traumatic head injuries may be caused in certain sports like soccer, boxing, football, baseball, hockey and other high impact sports activities.
  • Explosive blast or combat injuries: This type of injuries affects those in active military service especially those who sustain a grenade shrapnel injury or a blast from an explosive charge that damages the brain cells. 

Epidemiology

In the United States, head injuries numbers to 1.5 million cases annually and three-fourths of which are classified as mild injuries. The relative incidence of head injuries in the Americas has reached 503 cases per 100,000 population with predominance among Native Americans. The incidence of elderly cases of traumatic injury deaths and hospitalizations in the United States has doubled that of the national average in 2003 [2].

In European countries, the rate of head injuries reaches a level of 91 cases per 100,000 cases annually. The exact incidence of traumatic injury may be hard to ascertain because patients who suffer brain dysfunctions with temporal amnesia will have difficulty in recalling the accounts of his head trauma in the emergency room [3].

The Center of Diseases and Control (CDC) has conveyed that more than 50,000 die each year due to traumatic head injuries and almost 100,000 incur permanent disability due to the said injury.

Afro-Americans races have an associated worse outcome of traumatic head injury compared to their white counterparts. There is a male preponderance for traumatic head injury in over two folds the risk compared to females worldwide. More than half of traumatic head injury worldwide is aged 24 years or younger.

Sex distribution
Age distribution

Pathophysiology

The pathophysiology of traumatic head injury is conveniently divided into three brain insults namely: Structural traumatic insults, neurochemical insults, and secondary or indirect insults.

The structural traumatic insult includes incidences associated with the structural deformity of the skull like depressed skull fractures or a displaced skull fragment causing direct damage to the brain matter. The degree and extent of skull deformity may vary directly with the significance of the skull injury. The bridging cerebral vessels may be torn during the trauma which causes a subdural hematoma which may disrupt other cortical vessels in the brain. Trivial brain injuries may cause significant subdural hemorrhages in elderly patients [4].

Neurochemical insults correlates with surge of neurochemicals like catecholamine and hyroxyindole acetic acid (HIAA) in the cerebrospinal fluid (CSF) causing toxic effects to the brain tissues [5]. The initial brain trauma facilitates free radical release breaking down the lipid membranes of the neurons causing intraneuronal calcium accumulation and eventual cell death. Microdialysis of the CSF revealing the presence of excitotoxic aminoacids like glutamate and aspartate correlates with poor prognosis in traumatic head injuries [6]. Hypoxia and hypotension accounts for the majority of secondary insults associated with traumatic head injuries. Severe traumatic injury which halts the breathing centers of the hypothalamus may result to significant long-term or permanent brain injuries if oxygenation is not ensured at the site of the trauma during the rescue and extrication process [7].

Prevention

The following helpful tips are most useful in the prevention of traumatic head injuries:

  • Ensure the wearing of seatbelts when driving and make sure emergency airbags are working properly.
  • Refrain from using alcohol or illegal drugs before driving. 
  • Protective helmets may save one’s life when driving motorcycles and bicycles.
  • Hand rails and nonslip mats may prevent accidents in the bathroom.
  • Clear stairways of clutter and unnecessary obstruction.
  • Install good lighting in the living quarters.
  • Place shock absorbing material in children’s playground.

Summary

Head injury or traumatic brain injury happens when any external mechanical force to the head directly causes a temporal or permanent brain dysfunction. Head injury may also occur after a violent blow or jolt to the head or body part causing a penetrating injury to the skull like a projectile or a bullet.

Cerebral artery vasospasm may ensue as an immediate hemodynamic complication of traumatic brain injury causing intracranial hypertension in almost half of patients [1]. Serious traumatic head injury can result to brain bruising, torn tissues, and bleeding that may result to long standing complications or even death.

Patient Information

Definition

Head injury happens when an external mechanical force jolts the head causing temporary or permanent brain dysfunction.

Cause

Falls, vehicular accidents, armed conflict, sports injury and blast injuries are common causes. 

Symptoms

Altered state of consciousness, difficulty in respiration and rigidity may occur.

Diagnosis

Clinical examination and imaging studies like CT scan and MRI.

Treatment and follow-up

Mild traumatic head injury may not require any treatment. Medical decompression of the CSF pressure and neurosurgical treatment options may be necessary in more severe cases.

Self-assessment

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References

  1. Anderson P. Hemodynamic Complications Common in Traumatic Brain Injury. Accessed October 5, 2014.
  2. Rutland-Brown W, Langlois JA, Thomas KE, Xi YL. Incidence of traumatic brain injury in the United States, 2003. J Head Trauma Rehabil. Nov-Dec 2006; 21(6):544-8.
  3. Thurman D, Guerrero J. Trends in hospitalization associated with traumatic brain injury. JAMA. Sep 8 1999; 282(10):954-7.
  4. Matsuyama T, Shimomura T, Okumura Y, et al. Acute subdural hematomas due to rupture of cortical arteries: a study of the points of rupture in 19 cases. Surg Neurol. May 1997; 47(5):423-7.
  5. M, Seretis A, Kotsou S, et al. CSF neurotransmitter metabolites and short-term outcome of patients in coma after head injury. Acta Neurol Scand. Aug 1992; 86(2):190-3.
  6. Bullock R, Zauner A, Woodward JJ, et al. Factors affecting excitatory amino acid release following severe human head injury. J Neurosurg. Oct 1998; 89(4):507-18.
  7. Wang HE, Peitzman AB, Cassidy LD, et al. Out-of-hospital endotracheal intubation and outcome after traumatic brain injury. Ann Emerg Med. Nov 2004; 44(5):439-50.
  8. Chestnut R., Ghajar J., Maas A., Marion D, Servadei F., EARLY INDICATORS OF PROGNOSIS 
  9. In Severe Traumatic Brain Injury.
  10. Reale F, Delfini R, Mencattini G: Epidural hematomas. J Neurosurg Sci 28:9-16, 1984
  11. Rosner MJ, Rosner SD, Johnson AH. Cerebral perfusion pressure: management protocol and clinical results.J Neurosurg. Dec 1995; 83(6):949-62.

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