Concussion and Other Head Injuries BY: DR.KUCHA
Concussion• refers to an immediate but transient loss of consciousness that is associated with a short period of amnesia.• The mechanics of concussion involve a blunt forward impact that creates sudden deceleration of the head and an anterior- posterior movement of the brain within the skull.
Contusion, Brain Hemorrhage, and Axonal Shearing Lesions• Contusion: consists of varying degrees of petechial hemorrhage, edema, and tissue destruction.• The clinical signs are determined by the location and size of the contusion.• A hemiparesis or gaze preference is fairly typical of moderately sized contusions.• Large bilateral contusions produce coma with extensor posturing, while those limited to the frontal lobes cause a taciturn state.
• Contusions in the temporal lobe may cause delirium or an aggressive, combative syndrome.• Contusions are easily visible on CT and MRI scans, appearing as inhomogeneous hyperdensities on CT and as hyperintensities on MRI.
Subdural and Epidural Hematomas• Acute Subdural Hematoma:• most patients with ASH are drowsy or comatose from the moment of injury.• Direct cranial trauma may be minor and is not required for ASH to occur.• Acceleration forces alone, as from whiplash, are sometimes sufficient to produce subdural hemorrhage.
• Stupor or coma, hemiparesis, and unilateral pupillary enlargement are signs of larger hematomas.• Small subdural hematomas may be asymptomatic and usually do not require evacuation.
• On imaging studies subdural hematomas appear as crescentic collections over the convexity of one or both hemispheres, most commonly in the frontotemporal region, and less often in the inferior middle fossa or over the occipital poles.• The bleeding that causes larger hematomas is primarily venous in origin, although additional arterial bleeding sites are sometimes found at operation and a few large hematomas have a purely arterial origin.
• Epidural Hematoma:• These evolve more rapidly than subdural hematomas and are correspondingly more treacherous.• Most patients are unconscious when first seen. A "lucid interval" of several minutes to hours before coma supervenes is most characteristic of epidural hemorrhage.
EPIDURAL HEMATOMA • The tightly attached dura is stripped from the inner table of the skull, producing a characteristic lenticular-shaped hemorrhage on noncontrast CT scan. • Epidural hematomas are usually caused by tearing of the middle meningeal artery following fracture of the temporal bone.
• Chronic Subdural Hematoma:• A history of trauma may or may not be elicited in relation to chronic subdural hematoma. The causative injury may have been trivial and forgotten; 20–30% of patients recall no head injury.• CLINICAL FEATURES:• features may include slowed thinking, vague change in personality, seizure, or a mild hemiparesis.• The headache may fluctuate in severity.• Bilateral chronic subdural hematomas produce perplexing clinical syndromes.
Grading and Prognosis• In severe head injury, the clinical features of eye opening, motor responses of the limbs, and verbal output have been found to be generally predictive of outcome.• These three features are summarized in the Glasgow Coma Scale (GCS).
Glasgow Coma Scale for Head InjuryEye opening (E) scoreSpontaneous 4To loud voice 3To pain 2Nil 1
Best motor response (M) scoreObeys 6Localizes 5Withdraws (flexion) 4Abnormal flexion 3posturingExtension posturing 2Nil 1
• Coma score = E + M + V.• Patients scoring 3 or 4 = 85% chance of dying or remaining vegetative.• scores >11 = 5–10% likelihood of death or vegetative state and 85% chance of moderate disability or good recovery.• Intermediate scores correlate with proportional chances of recovery.