Injuries to the CNSPresented By: Steven Jones, NREMT-P

Objectives• Review Anatomy of CNS• Understand Nerve Function• Review Basic Divisions of the Brain• Identify important factors when assessing a

CNS injury• Identify specific findings with a CNS

disorder

The Nervous System

• The nervous system is the body’s control system

• It regulates nearly all bodily functions

• Electrical impulses travel up and down the nerves

Divisions of The Nervous System

• The Nervous System is divided into two parts:

• The Peripheral nervous system, composed of the cranial nerves and peripheral nerves.

• The Central nervous system consists of the brain and spinal cord.

Nerves and Brains

OUCH!

The Nervous System• CNS is the “computer” it

recognizes and responds• The peripheral nervous

system transmits impulses

• First sensory (afferent) then motor (efferent)

The CNS

• Consists of the brain and spinal cord

• The brain is located in the cranial cavity

• The spinal cord attaches to the lower portion of the brain through the foramen magnum

• Spinal cord is in the spinal cavity

The Neuron

• Consists of the cell body (nucleus) • Dendrites, carry impulses to the nerve cell• Axons, carry impulses away • When a sensation is felt it travels down the

dendrite through the nucleus and finally down the axon (long tail)

The fundamental unit of the nervous system

Neurotransmitters

• These chemical “messengers” travel across the synapse and stimulate the next nerve or terminal organ.

Neurotransmitters

• The neurotransmitter for the parasympathetic nervous system is acetylcholine (ACh).

• The neurotransmitter for the sympathetic nervous system is norepinephrine.

• The brain uses other neurotransmitters too, such as dopamine and serotonin.

Synapse• Where the axon of one nerve and the dendrite of

another meet… • A chemical is released across the synapse called a

neurotransmitter.

The Cranial Nerves

Only a Dozen or so...

• I Olfactory nerve• II Optic nerve• III Oculomotor nerve

(pupil)• IV Trochlear (eye

movement)• V Trigeminal nerve• VI Abducens nerve

(eye movement)

• VII Facial nerve• VIII Acoustic nerve• IX Glossopharyngeal

(taste)• X Vagus nerve• XI Spinal accessory

nerve• XII Hypoglossal nerve

Injuries

Assessment

•Injuries to the CNS may be subtle or dramatic, and assessment may be difficult

•Initial assessment should always begin with a thorough primary assessment

•AVPU is an important indicator of possible CNS injury.

•Give top priority to airway and c-spine control in the unconscious patient

•To determine if trauma is a factor a detailed secondary assessment and history is essential

Head to Toe Survey• The head to toe survey for the CNS patient should include

a standard examination and a more detailed neurological exam

• Special areas of concern are: pupils, respiratory status and spinal evaluation

Pupils• Pupils are controlled

by the third cranial nerve.

• The nerve follows a long course through the skull and is easily compressed

• They react quickly in changes in intercranial pressure and cerebral hypoxia.

• Dilated pupils that remain reactive to light may be the first sign of increasing intercranial pressure.

• The patient who presents with one dilated pupil is in the immediate transport category.

• This may indicate a CNS injury on the same side of the brain.

Respiratory

• Respiratory changes are common in patients with CNS injury or illness.

• There are five common patterns identified with brain injury.

• However there may be other reasons for changes in respiratory status.

• Cheyne-stokes increasing depth and frequency followed by periods of apnea

• Central Neurogenic hyperventilation usually caused by a lesion in the CNS. Rapid, deep, noisy respirations

• Ataxic respirations poor respirations due to CNS damage causing ineffective thoracic muscular coordination

• Apneustic respiration prolonged inspiration and very short expiration

Spinal Evaluation

• The purpose of the spinal exam is to identify possible traumatic injury and to document loss of sensation or motor function

• Observe for pain, tenderness or obvious signs of trauma• Check for pulse, motor and sensation in all extremities

check equal grip strength• Have the patient smile or stick out their tongue to evaluate

facial nerve function if you suspect a CNS injury/illness

Vital Signs

• If you suspect increased intercranial pressure, evaluate your patient often for signs of Cushings response

• Increased blood pressure• Decreased pulse• Decreased/altered respiration's• Increased temperature

Baseline

• It is important to obtain “baseline vital signs and neuro-status (AVPU) to compare with later assessments

• This will help emergency room staff to determine if the patients status is improving or deteriorating

• These assessments should be completed frequently

Subtle CNS Injury

Be Alert for these kinds of Injuries

Posturing

• Decorticate- arms flexed, legs extended

• Followed by…• Decerebrate-arms and

legs extended• Both are ominous signs

of deep cerebral or upper brainstem injury

Medical Reasons

For CNS Deficits

The Most Common...

• Altered mental status (for a variety of reasons)• Seizures• Stroke

Altered Mental Status• There are many reasons why a person may present with altered mental

status. Some of the more common reasons are: • Trauma• Brain tumor• Stroke• Narcotics/substance abuse• Diabetes• Kidney failure• Anaphylaxis• Cardiac disturbances• COPD• Meningitis

How Do You Remember ?

• A=acidosis, alcohol• E=epilepsy• I=infection• O=overdose• U=uremia, kidney

failure

• T=trauma, tumor• I=insulin• P=psychosis• S=stroke

A. E. I. O. U. T. I. P. S.

Management

•Maintain c-spine control

•Ensure adequacy of airway/provide supplemental 02

•Establish IV draw blood and check BGL

•Monitor cardiac rhythm

•If BLG <80 administer D50 IV

•Thiamine 100 mg IV/IM if suspected ETOH or malnutrition

•Narcan 2mg IV if suspected opiate overdose

•Maintain SP02 >98%

•Hyperventilation of head injury patients is controversial

•EtCO2

Seizures

Types of Seizures

• Grand mal-whole body tonic, clonic seizure resulting in loss of consciousness or a “postictal” state

• Focal motor- dysfunction of a localized area of the body• Psychomotor-unusual smell, taste, sound or vision. These

patients may briefly loose contact with their environment• Petit mal- a brief generalized seizure that usually lasts 10-

30 seconds the event may be so brief that the patient or observers may not even notice it. No postictal period follows

• Hysterical- aromatic ammonia may help differentiate a hysterical seizure from a true seizure

Seizure Treatment

Rx• Treatment for seizure patients is the same as the

treatment of altered mental status• However, care must be taken to ensure the

postictal patient does not vomit and aspirate• If actively seizing do not restrain patient but

prevent injury• Status epilepticus administer diazepam 5-10mg IV• If ineffective consider Ativan 2-4mg IV or IM if

no IV access• Consider 1 amp D50 IV (Why?)

Stroke

CVA Or TIA

• A CVA, commonly known as a stroke results from the death or damage of brain tissue usually due to a loss of cerebral blood flow. Either from a ruptured blood vessel or a clot

• A TIA is a “transient ischemic attack” that is similar in symptoms to a stroke but the effects are transient (short term)

Causes• Strokes are caused by a hemorrhage into the brain • An embolus (air) in the cerebral blood vessel• A thrombus that forms and occludes a cranial

artery

Signs and Symptoms• Symptoms of the stroke patient will depend on the area of

the brain affected. They typically experience loss of movement or sensation and altered speech

• The symptoms will have a sudden onset and the patient may lose consciousness

• There also may be labored breathing with snoring respirations due to paralysis of the soft palate

• The patients pupils may be unequal with the larger one on the side of the hemorrhage

• Paralysis is usually on one side of the body and the eyes may be turned away from the affected side

•Because of impaired blood flow to the brain, the stroke patient should be kept supine with the head elevated about 15 degrees for venous drainage

•Establish and maintain an adequate airway

•Support ventilations/oxygen

•**Hyperventilate if unresponsive** (controversial)

•IV TKO

•Cardiac monitor

Treatment for Stroke

•Draw blood and check BGL

•Use caution with D50 in suspected CVA (Why?)

•Reassure the patient.

•Remember even though they cannot speak, or appear to be D.O.B. they may hear and remember everything.

Treatment for Stroke

Don’t Stroke and Drive