head injury

Dr. saad farhan almasoudi

5 th Class
College of
Medicine

(Neuro Surgery)

Head injury

Is a major public health problem .

Is the most common cause of mortality and morbidity .
Commonly affect healthy children and active young adults .
Is largely preventable .

* Causes :

RTA 50%
Assault
Sports
Industrial accident
5.Fall from height
*prevention :
Is the most effective means of improving survival rates .
Little can be done as a treatment ,

improving safety devices in cars .
safety laws : seat belts , helmets , .est
public education .


These measures can reduce mortality and morbid by 30 80 %

* Classification of Head injury :

skull fracture with or without brain injury
vault fracture :linear,depressed,comminuted
and diastatic #.
base fracture:almost always linear and associated
with CSF leak.

Focal brain injury which includes

Brain contusion which define as abruises of neural parenchyma , always traumatic , wedge in shape , involve cortex surface associate with intact pial glial membrane and these contusion subdivided to
Coup ------ below site of impaction.
Contre coup ------ remote from site of impact.
Intermediate ------ within brain parenchyma between site of impaction and opposite side of brain .
. Hemorrhage / hematoma
epidural
subdural
Intra cerebral
petechial

3.Diffuse brain injury

concussion :- a transient reversible neurological dysfunction due to trauma not sufficient to cause structural damage to bruin parenchyma .
diffuse axonal injury : structural damage to brain leading to prolong coma not caused by mass effect , its severity depend on
magnitude of injury
duration of acceleration
rate of acceleration
direction of acceleration .


*Mechanisms of Head trauma :

Contact injury : slow , focal brain injury this require that head strikes an object or is struck , regard less of whether the blow causes the head to move after ward . and include .
Local contact injury (effects ) examples ,
linear skull fracture
depressed skull fracture
s.t. fracture base of skull
epidural hematoma
coup contusion
remote contact injury ( effects) :example
vault fracture
fracture base of skull
contre coup contusion
intermediate coup contusion
intracerebral hemorrhage

2.Head motion ( inertial ) injury :

inertial injury are often called head motion injury or acceleration injuries because the result from violent head motion , regardless of whether the head moves because of a direct blow or not .
Inertial loading of head cause rapid movement of the head that resultant injury is due only to the manner in which the head moves .

Head motion injuries termed acceleration injuries and these acceleration classified to

transilation acceleration
Rotational acceleration
Angular acceleration(both transition) and rotation type , combine together )


Head motion injuries classified to :
skull brain relative motion
subdural hematoma
contra coup contusion
intermediate coup contusion
Brain Deformation
Concussion syndrome
Diffuse axonal injury
Intracerebral hemorrhage
Tissue tear hemorrhage

*patho physiology of traumatic brain injury :

Ischemia which caused by
↑ ICP
Local destinations by space occupying lesions.
Severe vasoconstriction caused by release of K+ from ICC to ECC .

Hypoxia due to

Respiratory dysfunction
Inadequate ventilation
Problems in O2 delivery
Acidosis : which a consequence of ischemia and hypoxic leading to lactic acid acidosis that affect protein synthesis and function →cell membrane neuronal damage .
free radicles formation : ( H2O2 ) which occur from reperfusion after trauma → neural damage


S - ↑ neurotransmitter → release secondary to ischemia like glutamate → neurotoxicity .

*Systemic manifestation of traumatic brain iny :

1. Abnormality of water and electrolyte homeostasis :
Hypernatremia
diabetes insipidus
poor fluid intake .
hypo natremia
SIADH with ↑ blood volume
Cerebral salt wasting syndrome same as SIADH but with decrease in blood volume
hormonal abnormalities ( hypo and hyper secretion of anterior pituitary hormones ) , increase catacholamines production .
Metabolic change , ( hyper metabolic state , depressed cellular immunity
cardio pulmonary malfunction
cardiac - subendocardial hemorrhage
cardiac arrhythmia
heart failure
pulmonary - neurogenic pulmonary edema ( few minute )
- delayed pulmonary dysfunction 24 48 hr after trauma

* pathology of closed head injury :

Can be claisifiy to
soft tissue injuries of head and neck
periorbital ecchymoses ( Raccoon eye )
postauricular ecchymoses ( battle's sign )
scalp ( abrasion , laceration , contusions )
facial injury
peripheral cranial nerve
retinal hemorrhage.

skull fracture :

linear #: most common type seen in severe head injury cause by out bending of bone at a distance from impact side as a result of general deformation of skull .
depressed # : can be define when the outer table of depressed segment of bone below the inner table of the non depressed segment .
comminuted # : multiple linear # .
diastatic # : are linear fractures along sutures line resulting in separation of cranial sutures .

Brain injuries :

A . primary brain injuries include.
1. Focal injuries :
Hematoma which are
- intracerebral H.
-extradural H.
-subdural H.
-subarachoid H.( most common )



Contusion / lacerations of .
- brain tissue
- brain stem
- cranial nerve
- blood vessels
- pituitary gland and
hypothalamus .

2. Diffuse injuries :

Concussion
Diffuse axonal injuries .

B. secondary brain injuries due to :

1. Ischemia of brain tissue neural tissues caused by
↑ICP and herniation
Mass effect
K + extracellular release and vasoconstrictor

2. hypoxia dne to :

Hypotension
Hypoventilation
Respiration dysfunction
Inadequate O2 deliver to tissues .


* Evaluation of patient with head trauma :

A . General evaluation : which include

1.Vital signs:BP,PR.RR. and ventilation.

2. head and neck , site of trauma

3. other part of body like chest , abdomen , extremities .

4. reason behind head trauma .

B. neurological evaluation : which include

1. Glasgow coma scale ( GCS ) for state and level of consciousness
2. pupils and cranial nerve examinations
Pupillary light reflex , dolls eye( oculocephalic reflex ) , swallowing and vocal cord function .
3. motor responses : movement type , weakness , posture whether flexor or extensor .
4. sensory responses : painful stimuli commonly include nail bed pressure or nipple pinching lead to patient arousal .

5. Reflexes :

Brain stem reflexes
Cranial nerve reflexes
Muscle stretch reflexes


6. Respiration :
Cheyne stokes breathing →cortical lesion
Uniform hyperventilation → pontine lesion
Irregular , ataxic breathing → medullary lesion

7. Brain death examination :

Apnea test
Brain stem reflexes
EEG ( electroencephalography )
Angiography

8. Glasgow out come scale

5 → good recovery
4 → moderate disability , independent
3 → severe disability , conscious , dependent
2 → persistent vegetative state
1 → Death

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