1. ALI AL-BUSAIDIR4 APPROACH TO TRAUMATIC BRAIN INJURY

2. OUTLINES

Introduction

Definition

Pathophysiology

Severe head injury

Minor head injury

Second impact syndrome

Cerebral herniation

3. INTRODUCTION

Traumatic brain injury (TBI) encompasses a broad range of pathologic injuries to the brain of varying clinical severity that result from head trauma.

MVC ---- young

Fall ---- elderly

4. ETIOLOGY

MVAapprox. 28-50%

Falls 20-30% (infants, children, elderly)

Assaults 9-10%

Sports and recreational - 10-20%

5. DEFINITIONS

Head injury:

Injury is clinicallyevident on physical examination.

Traumatic brain injury:

Not always clinically evident.

6. CLASSIFICATION

Clinical severity scores

Neuroimaging scales

Leading Cause - MVAapprox. 28-50%

0-20%

7. 8. 9.

PROGNOSISCohort studies have suggested that patients with severe head injury (GCS 8) have about a 30 percent risk of death and only about 25 percent achieve long-term functional independence .

10.

Specific outcome predictors include :

GCS at presentation (especially the GCS motor score)

CT findings (subarachnoid hemorrhage, cisternal effacement, midline shift)

Pupillary function

Age

Associated injuries

Hypotension

Hypoxemia

Pyrexia

Elevated ICP

Reduced CPP

Bleeding diathesis (low platelet count, abnormal coagulation

11. PATHOPHYSIOLOGY

primary brain injury

secondary brain injury.

12. PRIMARY BRAIN INJURY

occurs at the time of trauma.

Common mechanisms include direct impact, rapid acceleration/deceleration, penetrating injury, and blast waves.

The damage that results includes a combination of focal contusions and hematomas, as well as shearing of white matter tracts (diffuse axonal injury) along with cerebral edema and swelling.

13. 14. Diffuse axonal injury

Shearing mechanisms lead to diffuse axonal injury (DAI), which is visualized pathologically and on neuroimaging studies as multiple small lesions seen within white matter tracts.

present with profound coma without elevated intracranial pressure (ICP), and often have poor outcome.

Involves the gray-white junction in the hemispheres

15. 16. Epidural hematomas

Typically associated with torn dural vessels such as the middle meningeal artery

are almost always associated with a skull fracture

are lenticular-shaped

tend not to be associated with underlying brain damage

17. 18. Subdural hematomas

result from damage to bridging veins

Are crescent-shaped

are often associated with underlying cerebral injury

19. 20. Subarachnoid hemorrhage

can occur with disruption of small pial vessels

commonly occurs in the sylvian fissures and interpeduncular cisterns.

may also extend into the subarachnoid space .

21. Intraventricular hemorrhage

Is believed to result from tearing of s ubependymal veins, or by extension from adjacent intraparenchymal or subarachnoid hemorrhage.

22. SECONDARY BRAIN INJURY

a cascade of molecular injury mechanisms :

Neurotransmitter-mediated excitotoxicity causing glutamate, free-radical injury to cell membranes

Electrolyte imbalances

Mitochondrial dysfunction

Inflammatory responses

Apoptosis

Secondary ischemia from vasospasm, focal microvascular occlusion, vascular injury

23. 24.

Examples:

hypotension

hypoxia -- decrease substrate delivery of oxygen and glucose to injured brain

fever

seizures -- mayincrease metabolic demand

hyperglycemia

25. CUSHING'S REFLEX

is seen in only one third of cases of life-threatening increased ICP.

Triad of:

hypertension

bradycardia

diminished respiratory effort

26. INITIAL EVALUATION AND TREATMENT 27. Prehospital

The primary goal of prehospital management for severe head injury is to prevent hypotension and hypoxia

Early endotracheal intubation is generally recommended for patients with a GCS of 8 or less if performed by well-trained personnel.

If this expertise is not available, bag-mask ventilation is recommended.

28. Prehospital

In a meta-analysis of clinical trials and population-based studies , hypoxia (PaO2 90 mm Hg)

Vital signs including heart rate, blood pressure, respiratory status (pulse oximetry, capnography), and temperature require ongoing monitoring.

32. Emergency department

A neurologic examination should be completed as soon as possible

Neurologic status should be continuously assessed. Deterioration is common in the initial hours after the injury.

33. 34. Emergency department

The patient should be assessed for other systemic trauma.

evaluate and manage increased intracranial pressure

A complete blood count, electrolytes, glucose, coagulation parameters, blood alcohol level, and urine toxicology should be checked if indicated

35. Neuroimaging

Computed tomography (CT) is the preferred imaging modality in the acute phase of head trauma

should be performed as quickly as possible

CT scan will detect skull fractures, intracranial hematomas, and cerebral edema

36. Neuroimaging

Risk stratification

37. 38. 39. 40.

LOC

PTA

Depressed level of consciousness

Progressive , severe headache

Severe nausea or vomiting

Alcohol or drug intoxication

Age 3 feet

or five stairs)

42. NEW ORLEAN CRITERIA 43. COMPARISON OF THE CANADIAN CT HEAD RULE AND THE NEW ORLEANS CRITERIA IN PATIENTS WITH MINOR HEAD INJURY

Design, Setting, and PatientsIna prospective cohort study (June 2000-December 2002)that included 9 emergency departments in large Canadian community and university hospitals, the CCHR was evaluated in a convenience sample of2707 adultswho presented to the emergency department with blunt head trauma resulting inwitnessed loss of consciousness ,disorientation, or definite amnesia and a GCS score of 13 to 15 . The CCHR and NOC were compared in a subgroup of 1822 adults with minor head injury and GCS score of 15.

JAMA. 2005;294:1511-1518.

44. COMPARISON OF THE CANADIAN CT HEAD RULE AND THE NEW ORLEANS CRITERIA IN PATIENTS WITH MINOR HEAD INJURY

ResultsAmong 1822 patients with GCS score of 15, 8 (0.4%) required neurosurgical intervention and 97 (5.3%) had clinically important brain injury.The NOC and the CCHR both had 100% sensitivity but the CCHR was more specific (76.3% vs 12.1%,P 70 mm Hg and