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HEAD INJURY. TODD D. ALEXANDER, M.D. OBJECTIVES. To review the spectrum of specific types of head injury To understand the management principles of severe head injury in the emergency room and ICU To understand some of the issues regarding concussion and athletic head injury. CASE STUDY.
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HEAD INJURY TODD D. ALEXANDER, M.D.
OBJECTIVES • To review the spectrum of specific types of head injury • To understand the management principles of severe head injury in the emergency room and ICU • To understand some of the issues regarding concussion and athletic head injury
CASE STUDY • A 9 year boy was playing on the railroad tracks and was struck by a train. He was intubated in the field and brought by emergency transport to the hospital. He was found to be lethargic but arousable with a large open wound on the right side of his scalp and an obvious skull defect. There were no other injuries and his vital signs were stable.
OUTLINE • Epidemiology • Pre-hospital Management • ER Management • Neurologic Assessment • Focal vs. Diffuse Brain Injuries A. Focal Injuries 1. Epidural Hematoma 2. Subdural Hematoma a. Acute b. Chronic 3. Skull Fractures 4. CSF Leaks B. Penetrating Injuries 1. Missile 2. Nonmissile
OUTLINE VI. ICU Management A. ICP management 1. Philosophy 2. ICP monitoring a. Indications b. Technques c. Treatment threshold 3. ICP lowering measuares a. Hyperventilation b. Mannitol c. Barb Coma d. Craniectomy e. Lobectomy B. Steroids in head injury • Antiepileptics in head injury • General critical care • Brain Death • Minor head injury • Concussion • Second impact syndrome • Athletic head injury • Case study
EPIDEMIOLOGY • Trauma causes 150,000 death/year – 50% due to head injury • Peak incidence in young adults age 15-24 • Most common cause is transport related followed by falls – urban areas: assaults and firearms
PREHOSPITAL MANAGEMENT • Transportation: into of helicopters, paradoxical mortality figures • Airway management: effect of hypoxia on outcome • Hypotension and fluid resuscitation: rapid resuscitation • Spine immobilization: 5-10% of head injured patients have associated spine and/or spinal cord injury
ER MANAGEMENT • ABC’S CT scan (non-infused) • Non infused head CT is the diagnostic cornerstone of head CT • Routine skull x-rays – historic relic (special indications) • ER burr holes – historical relic except in extremely unusual circumstances
ER MANAGEMENT (continued) • Airway: GCS≤8 intubate, sedation in the borderline patient, advantages, disadvantages • Fluid resuscitation: hypotension to be strictly avoided • ICP management: papillary changes or lateralizing sign mannitol, hyperventilation • Seizures: single seizure in the first 24 hours – no Rx, Rx of status epilepticus
NEUROLOGICAL ASSESSMENT • Glasgow Coma Scale • Eye opening: 4 • Best verbal response: 5 • Best motor response: 6 • Pupilary exam: herniation syndrome, pathophysiology, false localizing sign
FOCAL VS. DIFFUSE BRAIN INJURY • Focal: contusion (coup, contracoup), hemorrhage/hematoma (epidural, subdural, intracerebral, petechial) • Diffuse: concussion, diffuse axonal injury
EPIDURAL HEMATOMA • Radiographic diagnosis • Pathophysiology • Clinical presentation – “lucid interval” • Significance – “talk and die” • Management • Special cases (delayed, asymptomatic, posterior fossa, vertex)
SUBDURAL HEMATOMA • Radiographic diagnosis • Acute vs. chronic subdural hematoma • Pathophysiology • Clinical features • Management • Special cases (isodense subdural)
SKULL FRACTURES • Linear • Comminuted • Depressed • “ping-pong” • Compound fractures • Fractures involving the frontal sinus • Basilar skull fracture • Growing fracture – post traumatic leptomenigneal cyst
CSF LEAK • Diagnosis • Significance • CSF otorrhea • CSF rhinorrhea • pneumocephalus
MISSILE PENETRATING HEAD INJURY • Gunshot wounds to the head are perhaps the most lethal traumatic injury • Epidemiology – public health crisis • Ballistics (and missile characteristics): KE=mv2 emphasis on velocity; dividing point at 1000ft/second
MISSILE PENETRATING HEAD INJURY (continued) • Management: initial evaluation, controversies regarding aggressiveness of debridement • Differences in series: military, suburban, urban, rural, suicide, American, European, gang-related violence • infection
MISSILE PENETRATING HEAD INJURY • CSF leak • Traumatic aneurysm formation • Post traumatic epilepsy
NON MISSILE PENETRATING WOUNDS TO THE BRAIN • Rare in western practice because of ready availability of hand guns • South Africa has world’s largest experience • Clinical picture can be confusing or misleading especially when only a trivial scalp wound is present
NON MISSILE PENETRATING WOUNDS TO THE BRAIN • Incidence of vascular lesions high – aggressive investigation • Pencil injuries BEWARE!
ICP MANAGEMENT • Overall goal – prevent secondary injury • Cushing’s triad – only in 33% • Hypertension • Bradycardia • Respiratory irregularity • Good ICP management requires an ICP monitor
INDICATIONS FOR ICP MONITORING • GCS 3-8 (severe head injury) after cardiopulmonary resuscitation and an abnormal CT scan • Severe head injury with a normal CT scan in the following situations: • Age> 40 years • Unilateral or bilateral motor posturing • SBP <90 mmHg
INDICATIONS FOR ICP MONITORING (continued) • Specialized indications even in the conscious patient: need for sedation/paralysis e.g. severe lung contusion, (ARDS) or prolonged operation is necessary
ICP MONITORING TECHNIQUES • Ventricular catheter connected to an external strain gauge is most accurate, low cost, and reliable (also allows for therapeutic CSF drainage) • Fiberoptic (Camino) devices placed in ventricular catheters provide similar benefits at higher costs
ICP MONITORING TECHNIQUES (continued) • Intraparenchymalfiberoptic ICP monitors are 2nd best option • Subarachnoid, subdural, and epidural monitors are currently less accurate
INTRACRANIAL TREATMENT PRESSURE THRESHOLD • Most recommended treatments be initiated if ICP> 20-25 mmHg (controversial) pure CPP-based therapy in which higher ICPs may be accepted in the face of adequate CPPs (>70 mmHg) is no longer recommended goal is CPP 50-70 greater than 70 is associated with increased risk of ARDS
ICP LOWERING MEASURES • Hyperventilation • Mannitol (lasix, urea, hypertonic saline) • Mild head elevation - controversial and neck positioning • Sedation • Paralysis • IV lidocaine for suctioning
ICP LOWERING MEASURES (continued) • Pentobarbital coma • Decompressive craniectomy • Cerebral lobectomy • **Never get into a cycle of managing ICP elevation without ruling out a surgically evacuable lesion
HYPERVENTILATION • Mechanism • Severe hyperventilation can be HARMFUL • PCO2 < 25 mmHg are to be avoided • Prophylactic hyperventilation, especially in 1st 24 hrs when CBF is low, is to be avoided
HYPERVENTILATION (continued) • General goal is intensive ICP management – PCO2 around 35-40 mmHg • Jugular venous oxygenation monitoring is now being used by some physicians to guide the use of hyperventilation • Brain tissue oxygenation monitoring is being utilized