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Head injury. Dr. B.Padmashini Department of Accident, Emergency & Critical Care Medicine. Vinayaka Mission Kirupananda Variyar Medical College & Hospital. Salem,Tamil Nadu. Head Injury.
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Head injury Dr. B.Padmashini Department of Accident, Emergency & Critical Care Medicine. Vinayaka Mission Kirupananda Variyar Medical College & Hospital. Salem,Tamil Nadu
Head Injury • Number One Killer in Trauma • 25% of all trauma deaths • 50% of all deaths from MVC • 200,000 people in the world live with the disability caused by these injuries
Assaults (Sickle injuries)
Basic Anatomy • Scalp • Skull • Meninges • Dura Mater • Arachnoid • Pia Mater • Brain Tissue • CSF and Blood
Intracranial Volume • 80% Brain Matter • 10% Blood • 10% CSF
The MONROE KELLIE doctrine Dictates that “the total volume of the intracranial contents MUSTremain constant”
Uncompensated state- ICP Elevated 75 ml 75 ml
Intracranial Pressure • The pressure of the brain contents within the skull is intracranialpressure (ICP) • The pressure of the blood flowing through the brain is referred to as the cerebralperfusionpressure (CPP) The pressure of the blood in the body is the meanarterialpressure(MAP) CEREBRAL BLOOD FLOW Normal CBF – 50ml/100gm of brain/min “AUTOREGULATION”
ROLE OF INTRACRANIAL PRESSURE • 10 mmHg - Normal • > 20mmHg - Abnormal • > 40mmHg - Severe • ICP deteriorates brain function poor outcome
Intracranial Pressure • CerebralPerfusionPressure (CPP) can be determined by the following formula: CPP = MAP - ICP • NormalCPPrangeis60 - 150forautoregulation to work well!
SYMPTOMS & SIGNS OF INCREASED ICP • Diminishing level of consciousness • Headache, vomiting, seizures • Cushing’s Triad – bradycardia hypertension abnormal respiration • Pupillary changes • Papilledema
PATHOPHYSIOLOGY • Primary Injury • Mechanical irreversible damage - brain lacerations, hemorrhages, contusions, and tissue avulsions, • Microscopy - primary injury causes permanent mechanical cellular disruption and microvascular injury.
Secondary Injury • Neurologic outcome after head trauma - degree of secondary brain injury. • Common Secondary systemic insults – Hypotension – SBP < 90 Hypoxia - Po2 less than 60 Anemia – reduces O2 Carrying capacity of the blood, to the injured brain tissue, • Other causes - hypercarbia, hyperthermia, coagulopathy, and seizures.
MECHANISM • BLUNT INJURY High Velocity Low Velocity • PENETRATING INJURY Gunshot Sharp instruments
Severity -GLASGOW COMA SCALE Mild - GCS 13 - 15 Moderate - GCS 9 - 12 Severe - GCS 3 - 8
MORPHOLOGY • SCALPINJURY Cephal Hematoma Subgaleal Hematoma
SKULLFRACTURES • Vault : linear/stellate depressed/non depressed open/closed
Basilar : with/with out CSF leak with/with out seventh-nerve palsy Battle sign Raccoon eyes CSF rhinorrhea
INTRACRANIALLESIONS • Focal : epidural hematoma subdural hematoma intracerebral hematoma
Epidural haematoma • Collection of blood & clot b/n dura matter and bones of the skull • Source Middle Meningeal Artery Dural Venous Sinuses • C/F Brief loss of consciousness, headache,drowsiness,dizzy,nausea,vomitting • Rapid clinical deterioration • Talk & die
SDH • Subdural hematomas • Most frequently from tearing of a bridging vein between the cerebral cortex and a draining venous sinus. • - acute - <24hrs - subacute – 24hrs-2wks - chronic - >2wks Shape-Crescent
Intra Cerebral Heamatoma • Formed within brain tissue & caused by shearing or tensile forces that mechanically stretch and tear deep small caliber arterioles • Most common in temporal and frontal regions • C/F depend on site involved
INTRACRANIAL LESIONS Diffuse : concussion multiple contusion hypoxic/ischemic injury
Concussion • Temporary & brief interruption of neurological function after minor head injury • Due to shearing / stretching of white matter fibres at the time of impact or temporary neuronal dysfunction • C/o headache, confusion, amnesia • CT/MRI cannot detect
DAI • Shearing forces disrupt the axonal fibres in the white matter • Shaken baby syndrome • Blunt trauma • Rapid rise in ICT. • Prolonged or permanent.
APPROACH TO A PATIENT WITH HEAD INJURY • History • Initial Assessment Primary Survey Secondary Survey
PRIMARY SURVEY Airway maintenance with cervical spine protection
Intubation with Cervical inline stabilization • Breathingandventilation : Intubation precautions Pre-medicate with Lidocaine, 1mg/kg IV 2 minutes prior to attempt • Laryngoscopy produces an ICP Spike
Circulation • Maintain MAP >90mmhg- adequate • Hematocrit >30% • Cushing reflex
Isolated intracranial injuries do not cause hypotension • LOOK FOR THE CAUSE OF HYPOTENSION
Disability • Pupil size • GCS Pupillary Changes Irregular shaped Equality? Constricted? Dilated? Vision Problems?
SECONDARY SURVEY • AMPLE history • Examination of Head to toe • Glasgow Coma Scale • Detailed Neurological Examination