Head Trauma (Case 32)

Chapter 49 Head Trauma (Case 32)



Michael W. Weaver, MD, Darric E. Baty, MD


Case: A 28-year-old male presents to the ED after a motor vehicle accident. He was an unrestrained driver with loss of consciousness. Upon arrival at the ED, he is belligerent, is not following commands, and has obvious facial/head trauma.



Differential Diagnosis













Skull fracture Subarachnoid hemorrhage Contusion
Epidural hematoma Subdural hematoma Diffuse axonal injury



Speaking Intelligently


When I encounter a trauma patient with a head injury, I first ensure that the ABCs have been adequately assessed and managed. A precise and thorough neurological examination is then performed during the secondary survey, noting Glasgow Coma Scale (GCS) score, pupil size and reaction to light, an extremity assessment, and a thorough motor/sensory examination. Once the patient is hemodynamically stable, a head CT should be performed. Patients who are alert and fully oriented generally do not require emergent neurosurgical intervention. Obvious head and facial trauma combined with agitation suggests a possible brain injury. The combination of the patient’s neurological examination and the head CT help the neurosurgeon determine the best course of action, be it close neurological monitoring in the ICU, ventriculostomy, or an emergent trip to the OR.



PATIENT CARE



Clinical Thinking



• Airway: Ascertain whether or not the patient can protect his or her airway. Patients with severe neurological injury require intubation to prevent aspiration and hypoxia.

• Breathing: The breathing pattern is important: irregular respirations are part of Cushing’s triad and denote brainstem compression. Intubation can be used to artificially raise the respiratory rate to lower the pCO2; this is a short-term but effective method of lowering intracranial pressure.

• Circulation: Hypertension and bradycardia are the two remaining features of Cushing’s triad that signal impending herniation and death. Hypotension must be avoided to prevent secondary brain injury.

• Disability: Cranial nerve function, GCS score, and extremity strength and sensation are important to assess.

• Exposure: Other significant injuries, including spinal fractures and scalp lacerations, may be easily overlooked if a full examination of the patient is not performed.


History



• What was the mechanism of injury? Was it a gunshot wound (large caliber vs. small caliber), an assault, a motor vehicle accident?

• Was there loss of consciousness? How long?

• What medications or drugs has the patient received or taken that might affect mental status?

• Does the patient have a previous neurological disorder or baseline impairment?

• AMPLE (Allergies; Medications; Past medical hx; Last meal; Events leading to presentation)


Physical Examination



A Is the patient too lethargic to maintain an adequate airway?

B Is the respiratory rate regular and not too fast or too slow?

C Do the vital signs point to a missed source of bleeding, or is the patient herniating?

D Is the patient’s neurological examination deteriorating? Are skull or facial fractures evident?

E Is there a large scalp laceration that requires washout and closure?


Tests for Consideration


















• CBC with automated differential: Looking for adequate platelet count should neurosurgical intervention be necessary
 $34

• PT/PTT/INR: Looking for coagulation abnormalities that would require correction to stop bleeding and allow for neurosurgical intervention
 $56

• Urine toxicology screen: Looking for evidence of substances that might impair the neurological examination
 $235

• Serum alcohol level: Looking for an intoxicated patient who could be belligerent for reasons not directly related to neurological injury
 $53



IMAGING CONSIDERATIONS









→ Head CT without contrast: Looking for hemorrhage and skull fractures, and the effect on the brain parenchyma
 $2,000





















Clinical Entities Medical Knowledge
Skull Fracture
PΦ A skull fracture is a break in the bones of the skull. Skull fractures typically bespeak head injury of significant force.
TP Skull fractures are usually associated with moderate to severe traumatic brain injury, although some patients may be awake and oriented.
Dx Clinical evidence of basilar skull fractures includes raccoon’s eyes (ecchymosis around both eyes), Battle’s sign (ecchymosis in the mastoid area), and cerebrospinal fluid (CSF) leaks through the nose (CSF rhinorrhea) or ears (CSF otorrhea). Head CT is usually the best test.
Tx Closed skull fractures do not generally require any surgical tx unless there is significant bony depression (greater than the adjacent inner table of the skull). CSF rhinorrhea or otorrhea can almost always be treated conservatively, but persistent leaks may require lumbar drainage or an epidural blood patch. Open skull fractures are usually washed out to prevent infection in patients who survive their injury. See Sabiston 20, 72; Becker 11.


















Epidural Hematoma
PΦ An epidural hematoma is a collection of blood between the inner table of the skull and the dura mater. Epidural hematomas are usually caused by meningeal artery avulsions or tears, the most common being the middle meningeal artery.
TP Patients may present with the classic “lucid interval” between the time of the initial injury and the time when they quickly deteriorate secondary to an enlarging hematoma and impending herniation.
Dx Epidural hematomas are commonly associated with a skull fracture in the temporal bone near the middle meningeal artery, but they can occur elsewhere. They usually have an elliptical appearance on CT and do not cross suture lines (coronal or lambdoid sutures).
Tx Epidural hematomas usually require emergent neurosurgical evacuation, but small stable hemorrhages in an intact patient may be observed closely. See Sabiston 20, 72; Becker 11, 47.




















Subarachnoid Hemorrhage
PΦ Trauma is the most common cause of subarachnoid hemorrhage.
Ruptured cerebral aneurysm is another common cause of subarachnoid hemorrhage, and this possibility should be considered, based on the location of the blood.
TP Subarachnoid hemorrhage is most often associated with other brain injuries, such as skull fractures or contusions. It is usually seen near the convexity and in the sulci.
Dx The hemorrhage is visualized on head CT. A lumbar puncture is not indicated in the setting of head trauma.
Tx The management of traumatic subarachnoid hemorrhage is expectant. Serial neurologic examinations and follow-up head CT scans are usually sufficient to exclude and/or watch for associated injuries. Sabiston 20, 72; Becker 47.


















Subdural Hematoma
PΦ A subdural hematoma is a hematoma that occurs in the space beneath the dura. It is caused by rupture of the bridging veins that pass from the surface of the brain to the dura, or by a cerebral contusion that has bled into the subdural space.
TP Subdurals are common in moderate and severe head injury; they can also be brought about by relatively minor trauma in the aging patient whose brain is atrophied and separated from the overlying skull and dural membranes.
Dx Acute and chronic subdural hematomas are easily detected on head CT scans. Subacute hemorrhages may be easily missed as they are isodense to brain. Regardless of age, the hematoma is crescent-shaped on head CT and will cross suture lines. Subdurals are commonly associated with significant underlying brain injury.
Tx Large, symptomatic subdurals are evacuated in the OR. Smaller hemorrhages must be followed as they tend to become chronic and may enlarge over time. See Sabiston 20, 72; Becker 11.


















Contusion
PΦ A contusion is simply a “brain bruise.” Just as bruises on the skin tend to look worse a few days after the injury, contusions can enlarge or appear on repeat head CT scans that were initially normal.
TP Contusions are often associated with other head injuries. Small contusions can be seen with relatively minor trauma, but large contusions typically imply a significant mechanism of injury.
Dx Contusions are diagnosed on head CT scans. They tend to appear on the surface of the brain, where the cerebrum has impacted the inner table of the skull; small contusions may be difficult to detect on CT scanners with lots of beam-hardening artifact.
Tx Most contusions can simply be followed with serial head CTs. Large, symptomatic contusions may require more aggressive intervention by a neurosurgeon. See Sabiston 20, 72; Becker 11.


















Diffuse Axonal Injury
PΦ Diffuse axonal injury implies tearing of the axons in the brain secondary to a large shearing force.
TP The forces required to produce this type of brain insult typically result in severe traumatic brain injury. Patients may present in coma or with severely depressed mental status but without a significant brain mass that would explain their condition.
Dx The dx is largely clinical, with corroborating radiographic evidence. Small, punctate hemorrhages at the gray-white junction are sometimes seen.
Tx Depending on the patient’s other neurological and radiographic injuries, a ventriculostomy may be required to monitor the intracranial pressure, which is often normal. Supportive care is provided as required by the patient’s condition. See Sabiston 20, 72; Becker 47.



ZEBRA ZONE


Metabolic derangements: Whereas it may appear that a patient’s change in mental status is related to head trauma, mental status abnormalities can also be associated with metabolic derangements, drug and alcohol intoxication, and underlying mental illness or prior neurological insult. It is important to consider that a nontraumatic etiology may underlie a change in mental status.

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Mar 20, 2017 | Posted by in GENERAL SURGERY | Comments Off on Head Trauma (Case 32)

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