Neurological Emergencies

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Disorders of the nervous system require rapid assessment and treatment. These types of problems are, however, often difficult to recognize.

Neurological disorders fall into two general categories:

  • Trauma-related
  • Medical (structural or metabolic)

Anatomy and Physiology

Cells

The nervous system's fundamental units include neurons and neuroglia. The neuroglia are specialized cells of the connective tissue that serve to bind neurons together. The neuron, which is the individual nerve cell, consists of three main parts:

  • Cell Body (Soma) - Contains a large, single nucleus, with a prominent nucleolus.
  • Dendrites - Branching projections of the neuron, which receive stimuli from the axons of other nerve cells, transmit impulses to the cell body. They are also referred to as receptors.
  • Axons -A single branch or elongated projection which transmits impulses away from the cell body. The axon may connect to another neuron's dendrites or directly to a muscle or sense organ.

Groups of neurons within the central nervous system are called nerves. Groups of nerves within the peripheral nervous system are called ganglia.

The neurilemma is a sheath that covers all nerve fibers. Some axons are covered by a fatty myelin sheath which serves as protection for the nerve fiber and also helps speed transmission of impulses along the axon. Fibers that contain a myelin sheath, or myelinated fibers, are referred to as white matter because the myelin sheath has a whitish coloring. Unmyelinated fibers are called gray matter.

The nervous system is the body's control system. Almost all body functions are regulated by electrical impulses transmitted through nerves. The impulses transmitted within the nervous system resemble the conduction of electrical impulses through the heart. When the neuron is in a state of rest, it contains a negative charge on the inside and a positive charge outside the cell. Upon stimulation, sodium enters the cell rapidly while potassium leaves the cell rapidly. This produces a positive charge at the site of entry. This positive charge is called the action potential which is transmitted down the neuron very rapidly.

Nervous System

The nervous system is divided into two parts:

  • Central Nervous System (CNS) - Consists of the brain and spinal cord.
  • Peripheral Nervous System (PNS) - Consists of cranial nerves, spinal nerves, and peripheral nerves.

The autonomic nervous system is a division of the PNS and it is further divided into two parts:

  • Sympathetic
  • Parasympathetic

Neurons join with other neurons at junctions known as synapses. The neurons do not come into actual physical contact here, but they communicate at the synapse by a release of a chemical neurotransmitter. The axon causes the release of these chemicals which cross the gap between the neurons and stimulate the connecting nerve.

The primary neurotransmitters released are acetylcholine and norepinephrine. Norepinephrine is found at the synaptic terminals of the sympathetic nerves. Acetylcholine is the neurotransmitter of the parasympathetic and voluntary nervous systems.

There are 43 pairs of nerves which originate within the CNS and go on to form the PNS. Twelve pairs of cranial nerves originate at the brain while the other 31 pairs of spinal nerves originate from the spinal cord.

Central Nervous System

The CNS is protected by bony structures. The brain is protected by the skull. More specifically, the brain lies within a cavity in the cranium known as the cranial vault. The cranium consists of bones of the head which include the frontal and occipital bones, and pairs of bones known as the parietal, temporal, sphenoid, and ethmoid bones found on either side of the head.

The spinal cord is protected by a total of 33 bones known as the spine. The spine includes 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 sacral vertebrae, and 3-5 coccygeal vertebrae. The spinal cord itself is housed within a cavity formed by most of these bones.

The CNS has a covering of protective membranes known as the meninges. The meninges consist of three layers:

  • Dura mater ("tough mother") - Outermost layer which is composed of a tough, white fibrous material. Adheres tightly to the skull.
  • Arachnoid ("spider web") membrane - Middle layer which has a weblike composition.
  • Pia mater ("gentle mother") - Innermost layer. A thin layer that adheres to the brain itself.

There is a space between the pia mater and the arachnoid membrane called the subarachnoid space. The space between the dura mater and the arachnoid membrane is called the subdural space. The space outside the dura mater and just below the skull is called the epidural space Blood can collect in any of these spaces in cases of trauma or ruptured aneurysm of an artery.

Cerebrospinal fluid (CSF) is a watery fluid that surrounds and bathes both the spinal cord and the brain. The CSF contains nutrients, including glucose.

The Brain

The brain is the largest single part of the CNS and is divided into six anatomical divisions:

Cerebrum - Found in the anterior and middle fossa of the cranium. It has two hemispheres that are joined by the corpus callosum. This part of the brain controls all sensory and motor functions. Here is where intelligence, learning ability, memory, speech, and analysis are controlled. The outermost layer is known as the cerebral cortex.

Diencephalon - The uppermost portion of the brainstem. Inside it are the thalamus, hypothalamus, and the limbic system. This is where several involuntary functions are controlled, such as:

  • Temperature regulation
  • Sleep
  • Water balance
  • Stress response
  • Emotion

The regulation of the autonomic nervous system is a major function of the diencephalon.

Mesencephalon - Located between the diencephalon and the pons, also known as the midbrain. Here is where eye movement and certain aspects of motor coordination is controlled.

Pons - Located between the midbrain and the medulla oblongata, connections between the spinal cord and the brain are found here.

Medulla Oblongata - Also known as the brainstem. Located between the pons and the spinal cord. Responsible for control of respirations, cardiac functions, and vasomotor activity. It marks the division between the spinal cord and the brain.

Cerebellum - Located in the posterior fossa of the cranium. It has two hemispheres. Coordination of posture, muscle tone, and equilibrium are its responsibilities.

You may be asking yourself, is it really necessary to be familiar with all the regions of the brain to function as a medic? The answer is, knowing the clinical significance of specialized brain functions can help you become a better medic. If you are able to associate areas of the brain with their respective areas of control functions, you will be able to better assess the patient suffering neurological deficits. Some areas of concern are:

  • Speech - Controlled by the temporal lobe of the cerebrum
  • Vision - Controlled by the occipital cortex of the cerebrum
  • Personality - Controlled by the frontal lobe of the cerebrum
  • Balance and coordination - Controlled by the cerebellum
  • Sensory function - Controlled by the parietal lobe of the cerebrum
  • Motor function - Controlled by the frontal lobe of the cerebrum

Blood Supply

There are two systems which supply blood to the brain: an anterior system, the carotid system; and a posterior system, the vertebro-basilar system. These two systems join at the Circle of Willis and then enter the brain. If one of the system's components fails to deliver blood flow, then the Circle of Willis is designed to ensure that adequate blood supply reaches all parts of the brain.

Blood leaves the brain through the venous sinuses and the internal jugular veins. Blood from the face, scalp, and neck drains into the external jugular veins.

Spinal Cord

The spinal cord is about 17 - 18 inches in length. It originates at the medulla oblongata and descends through the foramen magnum at the base of the skull and down the spinal canal. The spinal cord ends at about the level of the first lumbar vertebra. The end of the spinal cord is called the cauda equina because the nerves branch out and give the appearance of a horse's tail. The function of the spinal cord includes conducting impulses to the peripheral nervous system and controlling reflexes.

Reflexes are a protective measure. The reflex is an action to avoid harm. The impulses sent by the spinal cord allow a faster response because the signal does not have to originate from the brain. The reflex action that is mediated by the spinal cord is a faster one but lacks fine control because the brain is left out of the process.

As mentioned earlier, there are 31 pairs of spinal nerves that exit the spinal cord and form the peripheral nervous system. The dorsal roots contain afferent fibers and the ventral roots contain efferent fibers. Afferent fibers are sensory fibers and transmit impulses from the body to the brain. Efferent fibers are motor fibers and carry impulses from the brain to the body. There is an area called the dermatome which is the zone of the body that is served by one spinal nerve. The entire body is divided into 31 dermatomes corresponding with each pair of spinal nerves. Dermatomes are useful in the assessment of spinal cord injuries.

The severity of injury sustained to the spinal cord is determined by the location of the injury. The closer to the brain the injury occurs, the more serious the injury is in terms of total paralysis.

Peripheral Nervous System

The peripheral nervous system contains both voluntary and involuntary components. There are twelve pairs of cranial nerves which originate in the brain and control the neck and head. This area also controls some thoracic and abdominal organs. The peripheral nerves originate in the spinal cord and supply nervous control to the periphery.

There are four types of peripheral nerves:

  • Somatic Sensory - Transmit sensations of touch, pressure, pain, temperature, and position.
  • Somatic Motor - Carry messages to skeletal muscles.
  • Visceral Sensory - Transmit sensations from the organs, or viscera, such as the need to urinate or defecate.
  • Visceral Motor - These are fibers that leave the CNS and supply nerves to the viscera, such as glands and other organs.

The brachial plexus is a network of nerves that comes from the cervical and thoracic portion of the spinal cord and innervates the upper extremities. This area is sometimes injured with upper extremity trauma or possibly at birth resulting in permanent disability.

Autonomic Nervous System

The autonomic nervous system controls involuntary bodily functions. This system plays an important role in maintaining homeostasis by the nervous system's regulatory and coordinating activities. This system has two divisions, the sympathetic and the parasympathetic nervous system:

Sympathetic Nervous System

Sometimes referred to as the "fight or flight" system, this is what prepares us to deal with highly stressful situations. Stimulation of this system causes an increase in heart rate and blood pressure. It causes the pupils to dilate as well as the bronchioles. The blood sugar rises as a result of sympathetic stimulation. The chemicals responsible for the mediation of this system are the neurotransmitters epinephrine, which is released by the adrenal gland, and norepinephrine, which is released from sympathetic nerve endings.

Parasympathetic Nervous System

Sometimes referred to as the "feed or breed" or "rest and repair" system, this system, when stimulated, causes an opposite effect than that of the sympathetic nervous system. It increases digestive activity, reduces blood glucose levels, decreases the heart rate and blood pressure, and causes pupillary constriction. The primary neurotransmitter in the parasympathetic nervous system is acetylcholine.

An important component of the parasympathetic nervous system is the vagus nerve, which is the 10th cranial nerve (CN X). The vagus nerve controls actions of the heart, stomach, and GI tract. When the vagus nerve is stimulated, the heart rate slows down.

The vagus nerve is stimulated by a maneuver called the Valsalva maneuver, which is the exertion of pressure against a closed glottis. Bearing down, coughing, or stimulation of the gag reflex are all Valsalva maneuvers. Some syncopal episodes are caused by stimulation of the vagus nerve by the Valsalva maneuver, especially in elderly individuals.

These two systems co-exist in relative harmony during normal conditions. When we encounter stressful situations the sympathetic system rules. When we are at rest, the parasympathetic system dominates.

Assessment of the Neurological System

As stated in the introduction, assessing neurological emergencies is often difficult due to the subtleties of the presenting signs and symptoms. As always, start the assessment with a primary survey* and then proceed with a thorough secondary survey*. Concentrate on the neurological exam if a neurological emergency is suspected.

Primary Survey

Perform the primary survey as you ordinarily would, assuring that the airway is open and the C-spine is in neutral alignment. As always, if the patient is unconscious, assume possible spinal injury and use the appropriate methods to open the airway while maintaining C-spine control. Don't forget the basics, use an airway adjunct if needed to aid you in maintaining airway control.

Patients experiencing neurological problems need to have their respiratory status monitored skillfully and often. Intracranial pressure can result in abnormal breathing patterns as well as respiratory arrest. If the patient was involved in trauma, look for foreign objects and facial injuries that may lead to breathing difficulties.

Secondary Survey

The secondary survey should include a brief, pertinent medical history, a head-to-toe exam, vital signs, and a thorough neurological exam.

History

Gathering information concerning the patient's pertinent medical history can be complicated by the impaired mental function of the patient. Look to family members and bystanders if they are available. If you suspect trauma as the cause, ask and observe the following:

  • When did it happen?
  • What is the mechanism of injury?
  • Did the patient lose consciousness and for how long?
  • What is the chief complaint?
  • Have the patient's symptoms changed?

If the problem is not trauma related, you may want to know:

  • What is the chief complaint?
  • What underlying problems does the patient have?

·         Cardiac disease

·         Chronic seizures

·         Diabetes

·         Hypertension

·         Has the patient had this type of problem before?

·         Look around for;

·         Medications

·         Drugs

·         Medic alert tags

·         Alcohol

Head-to-Toe Exam

Concentrate on the neurological exam while performing the head-to-toe survey. This should include checking the pupils, respiratory patterns, a spinal evaluation, comparing the strength of grips, motor function and sensation of the hands and feet, and posturing exhibited by the unconscious patient.

Pupils

Intracranial swelling often affects the pupils. The pupils are controlled by the third cranial nerve which runs along the skull and is often squeezed by a swollen brain. This can offer early evidence of increased intracranial pressure.

Check the pupils for reactivity to light noting first the approximate size of the pupils prior to exposing them to light. As you shine light into the pupils take note of the size after constriction if there is any reaction. If both pupils fail to react to light this may be indicative of a brainstem injury, severe hypoxia, or anoxia. If both pupils are dilated, but still react to light, the injury may be reversible. Quick transport to an appropriate facility is a must. Pupils that present with one eye dilated and the other eye normal, where the dilated pupil reacts to light, can be one of the earliest signs of increasing intracranial pressure. Any patient who presents with this sign or develops this condition should be transported immediately. If the pupils are only slightly unequal, this could be a normal finding. Be sure to ask the patient or a family member if the patient may normally have unequal or irregularly shaped pupils. Monitor the patient closely when encountering pupils that are unequal and be alert for possible changes 

Another method of assessing eye movement is the Cardinal Positions of Gaze method. Have the patient follow your finger or an object you hold in front of them to the left, right, up, and then down. The patient should be able to follow in all directions. If they have difficulty following in any one direction this may be an early indicator of a CNS problem.

Respiratory Status

There are five common respiratory patterns that can be associated with neurological problems. They are:

  • Cheyne-Stokes Respirations - A breathing pattern characterized by periods of apnea followed by increased respiratory depth and frequency of respirations.
  • Central Neurogenic Hyperventilation - Rapid, deep, noisy respirations caused by a problem within the CNS.
  • Ataxic Respirations - Inability of the thoracic muscles to contract in a coordinated manner causing ineffective respirations due to CNS damage.
  • Apneustic Respirations - Caused by an injury to the upper portion of the pons, characterized by prolonged inspirations without relief by expiration.
  • Diaphragmatic Breathing - Use of the diaphragm to expand the thoracic cavity because the intercostal muscles are not being stimulated by the brain.

There are many things that can and do affect breathing patterns. Things such as fear, anxiety, chest trauma, diabetes, as well as many other factors can affect respiratory patterns. This is just another example of why assessing patients suffering neurological deficits is so difficult.

Treating the patient with suspected rising intracranial pressure should include hyperventilating with a bag-valve-mask and supplemental oxygen at a rate of 24 breaths per minute or greater. Be sure to use good technique when hyperventilating so as to avoid hypoinflation of the lower lungs. Hyperventilating does not mean to squeeze the bag-valve-mask as fast as you can. Use the entire contents of the bag-valve-mask in a smooth steady squeeze to ensure proper lung inflation. The patient that is not breathing properly will most likely have an abnormal level of carbon dioxide in their arterial blood. The normal level of PaCO2 is 40 mm Hg. An increase in PaCO2 causes cerebral blood vessels to dilate. A decrease of PaCO2 causes vasoconstriction. If the patient is poorly ventilated, this causes PaCO2 to rise which causes blood vessels to dilate, engorging them with blood and adding to intracranial pressure. Hyperventilating reduces the PaCO2 causing vessels to constrict and helps to minimize brain swelling.

Note: As with anything in the medical field, research is always being conducted to evaluate the effectiveness of certain techniques and therapies. Some current research does not advocate hyperventilating the patient with a neurological problem. Check your local protocols.

Spinal Evaluation

Evaluating the spine in the field should include assessing the patient's sensation and motor function in the extremities. The spinal column should be assessed for:

  • Pain and tenderness
  • Bruising
  • Deformities

Ask the patient to grip your index finger and middle finger in their hands simultaneously and give them a squeeze. Assess the strength of their grip and compare the grip strength of the left and right hands. If one side appears to be weaker in strength than the other, this could be a sign of neurological problems. Have the patient wiggle their toes. Grasp one toe between your finger and thumb asking the patient if they can feel you touching them and if they can tell you which toe you are touching. Have the patient describe the sensation when touching two different areas, if the sensation is sharp in one area and dull at the other area, this may be a significant finding. If you suspect possible spinal injuries, it may not be a good practice to use the push, pull method of assessing the lower extremities, this movement may aggravate a spinal injury. Checking the patient's motor function can be accomplished by having them wiggle their toes.

If a spinal injury is suspected, be alert for signs and symptoms of spinal shock which are different from the classic shock presentation. The patient will have a low blood pressure, but their heart rate will be normal or possibly bradycardic, and their skin will be warm and dry.

The use of the AVPU acronym and the Glasgow Coma Scale will aid you in the pre-hospital assessment of the patient with CNS injury.

EYE OPENING RESPONSE:

Spontaneous = 4

To Verbal Stimuli = 3

To Painful Stimuli = 2

No Response = 1

BEST VERBAL RESPONSE:

Oriented = 5

Confused = 4

Inappropriate Words = 3

Incomprehensible Sounds = 2

No Response = 1

BEST MOTOR RESPONSE:

Obeys Commands = 6

Localizes Pain = 5

Withdraws from Pain = 4

Flexion (decorticate posturing) = 3

Extension (decerebrate posturing) = 2

No Response = 1

The total score of the Glasgow coma scale can be an indicator of the chances for survival.

Scores

8 or better..............................................94% favorable outcome

5, 6, 7.....................................50% favorable (adult), 90% (child)

3, 4.....................................................10% favorable outcome

5, 6, 7 who drop a grade...................100% unfavorable outcome

5, 6, 7 who improve to more than 7.........80% favorable outcome

The lowest possible score is 3, the highest possible score is 15

If the patient is unconscious, you will need to determine whether or not the patient responds to verbal or painful stimuli. Use the AVPU scale to assess the level of responsiveness. If there is no response to verbal stimuli such as speaking in a loud tone of voice in an attempt to get a response, then you can use a sternum rub or a firm pinch of a fleshy area to try to get a response. If there is no response to this type of stimuli, then the patient is considered to be unresponsive. Make note of any incontinence as well.

Be alert for possible spinal shock, and be aware that the patient may vomit. Secure the patient on a long backboard and be prepared to turn the patient as a whole to the side if they vomit to prevent aspiration. Make sure the patient is on the long board very securely prior to turning them on the side.

Vital Signs

Baseline vitals and subsequent follow up vitals are important when assessing the patient with possible CNS problems. Increasing intracranial pressure is characterized by the following vital signs and is known as Cushing's Reflex:

Cushing's Reflex

Increasing blood pressure

Decreasing pulse rate

Decreasing frequency of respirations

Increasing body temperature

You will notice that these vital signs are generally opposite of those you would expect to find in the classic shock syndrome. The vital signs associated with Cushing's Reflex will tend to reverse towards the classic vital signs found in shock if intracranial pressure continues to rise unchecked. Body temperature will be the exception, it will remain elevated. Another sign is possible cardiac dysrhythmias. Careful monitoring of the heart by ECG will aid in assessing this type of patient. Another useful diagnostic tool is pulse oximetry.

Coma

Neurological System Emergencies

A patient suffering coma is in a very deep unconscious state. Attempts to arouse them by the use of external stimuli are found to be unsuccessful. There are two general physiological causes of coma:

  • Lesions of the ascending reticular activating system in the brainstem.
  • Metabolic abnormalities which produce circulating toxins or possibly the lack of metabolites such as oxygen or glucose which can cause depression of one or both cerebral hemispheres. This condition may also cause depression of the ascending reticular activating system in the brainstem.

Coma can be present as a result of these two mechanisms. The following is a list of six general causes of coma:

Structural Causes

  • Intracranial bleeding
  • Head trauma
  • Brain tumor or lesions

Metabolic Causes

  • Anoxia
  • Hypoglycemia
  • Kidney and liver failure
  • Thiamine deficiency
  • Postictal phase of seizure

Drugs

  • Barbiturates
  • Narcotics
  • Alcohol
  • Depressants
  • Hallucinogens

Cardiovascular

  • Hypertensive encephalopathy
  • Stroke
  • Dysrhythmias
  • Shock

Infection

  • Sepsis
  • Meningitis

Respiratory

  • Toxic substance inhalation
  • COPD

There are certain inorganic conditions which imitate coma. These include hysteria and psychogenic episodes. Patients experiencing these conditions are generally responsive to external stimuli, whereas patients experiencing organic causes of coma are unresponsive to external stimuli.

Mnemonics are very useful in remembering certain aspects of pre-hospital care and coma is no exception. A useful mnemonic to help in remembering causes of coma is AEIOUTIPS:

AEIOUTIPS

A - Acidosis, alcohol

E - Epilepsy

I - Infection

O - Overdose

U - Uremia

T - Trauma

I - Insulin

P - Psychosis

S - Stroke

There are two factors which can help EMS personnel distinguish between structural and metabolic causes of coma. When coma is due to structural effects, there is a common association of asymmetrical, focal neurological deficits such as weakness on one side, hemiparesis, and unequal pupils. When toxic metabolites are the culprit, neurological findings are often symmetrical. The onset of coma due to metabolic toxins is often slow compared to structural causes which is often acute.

Structural coma often follows a pattern of progressive deterioration which is caused by increasing intracranial pressure. The increasing pressure can cause herniation of the brain (the brain pushes through the opening at the base of the skull, or the foramen magnum) which would require rapid surgical intervention. Being able to distinguish between metabolic coma and structural coma can help you prepare to anticipate the course of a patient's condition.

Assessment and Management

Treatment is aimed at treating potentially reversible causes of coma by supporting the patient's vital functions, administering appropriate medications, giving intravenous fluids when needed and preventing further deterioration of the patient's condition

Hyperventilation at a rate of 24 breaths per minute will help reduce intracranial pressure by constricting blood vessels. Patients without a gag reflex should be intubated. After securing the airway, treatment of a patient with unknown causes of coma should include:

  • IV of Lactated Ringer's or normal saline per protocol.
  • Monitoring of the ECG
  • Check the blood glucose level and treat hypoglycemia per protocol.
  • Administration of thiamine may prevent dextrose from precipitating Wernicke's Syndrome or Korsakoff's Psychosis (an irreversible memory disorder) in alcoholic patients with depleted thiamine stores.
  • Naloxone may be given per protocol if there is no response to glucose in order to rule out or reverse narcotic overdose. You may need to give repeated doses of naloxone due to the duration of the narcotic which may be longer than that of naloxone. Titrate doses to keep the patient awake and to maintain a good respiratory pattern. When giving naloxone to patients with suspected drug overdose you will want to consider restraining the patient prior to administration. Many of these patients will wake up angry and abruptly (perhaps mad that you ruined their expensive high!).
  • Close the eyelids of the patient who fails to respond to the treatments indicated above to keep the eyes from drying out and causing damage. You may want to use moist 4 x 4's to cover the eyelids.
  • Transport the non-trauma patient in the lateral recumbent position if the patient fails to respond so that drainage of secretions is maximized and to minimize the risk of aspiration of stomach contents.
  • Closely monitor the patient and have suction available.

Often, an injury or illness of the central nervous system causes an alteration of mental status. Altered mental status is not a normal finding and requires further evaluation of the patient's condition. Mental status may vary from minor thought disturbances to complete unconsciousness. The deeply unconscious state is referred to as coma. This is where no amount of external stimuli raises a response from the patient.

Usually there are two causes :

  • Structural lesions that affect the brain tissue or destroy brain tissue.
  • Toxic-metabolic conditions where circulating toxins or metabolites or the lack of metabolites such as oxygen, glucose, or thiamine produces depression of both cerebral hemispheres.

Many causes of coma are too difficult to classify. There are some more common causes listed above in the section on coma. The mnemonic AEIOUTIPS is a useful tool in remembering the causes of coma.

Primary Survey

During the primary assessment, as in most cases, pay close attention to the airway and cervical spine in the unresponsive patient. Intubation is a viable option if you can rule out hypoglycemia as the primary cause of unconsciousness. The hypoglycemic patient should receive dextrose in an attempt to reverse their condition which may result in rapid reversal, and you don't want a conscious intubated patient on your hands. Self-extubation can be very painful. Hyperventilate the unresponsive patient to help reduce brain swelling if head trauma is the suspected culprit. Monitor the patient's airway and be alert for possible vomiting.

Secondary Survey

The secondary assessment will be helpful in determining the severity of the neurological deficit being experienced by the patient. Assess the patient by using the following steps:

  • History - Gather pertinent medical history from the patient's family, friends, or bystanders if available. History such as diabetes or drug abuse can be valuable in determining possible causes of impaired mental status. A recent history of head trauma or falls can be important. Look around and ask for medications the patient may be taking. Ask if the patient has been having similar problems recently. Use the following questions to guide your interview:
  • How long has the patient been experiencing this problem?
  • Was it a gradual or sudden onset?
  • Is there a recent history of head trauma within the last four weeks?
  • Is the patient currently under a doctor's care?
  • Does the patient have an alcohol or drug problem?
  • What were the preceding symptoms or complaints?
  • Is the patient currently taking any prescribed medications?
  • Look for any Medic-Alert tags.

Physical Exam

The initial evaluation of the patient should include:

  • Breathing (rate and quality)
  • Response to stimuli (AVPU)
  • Pupillary response

Examine the following areas for clues as to why the patient is unresponsive:

Pupillary reflex - The dilation and constriction of pupils is controlled by different nerve pathways. Constriction is a parasympathetic reaction while dilation is a sympathetic response. A failure in the midbrain can interrupt both pathways resulting in fixed, mid-sized pupils. Pinpoint pupils can point to lesions in the area of the pons. Compression of the third cranial nerve can result in a unilateral fixed and dilated pupil. Structural lesions often result in fixed or asymmetric pupils. Pupils that react to light generally indicate a toxic metabolic state.

Extraocular movement - The patient with a brainstem injury often presents with a dysconjugate gaze, which is eyes moving in an opposite direction than the head.

Motor response - Asymmetry implies structural lesions. If the patient responds to pain by localizing or withdrawing this may be an indicator of a minimal cortical impairment. A decerebrate or decorticate posturing is an ominous sign of deep cerebral or brainstem injury. Spinal injury usually results in a flaccid paralysis.

Respiratory patterns - Generally, abnormal respiratory patterns are not as reliable an indicator of central nervous system problems as pupillary response, extraocular movements, and motor response are. There are many factors that affect respiratory patterns. Kussmaul respirations and central neurogenic hyperventilation are virtually the same. Kussmaul respirations are generally associated with deep bilateral dysfunction of the cerebral hemispheres. Central neurogenic hyperventilations can point to a problem anywhere from the forebrain to the upper pons. Apnea can be due to a problem in the medulla.

Vital signs - Vital signs that point to central nervous system dysfunctions are:

  • Hypertension
  • Bradycardia
  • Abnormal respiratory patterns
  • Elevated body temperature

Management

Managing the patient's C-spine is a top priority if trauma is the suspected cause, along with management of the airway and supplying supplemental oxygen. If the patient's breathing is inadequate, supporting the respirations with a bag-valve-mask and supplemental oxygen is indicated. Make use of airway adjuncts to aid your treatment of the unresponsive patient.

After securing the C-spine and airway;

  • Make a determination of blood glucose levels using a reagent strip or preferably a glucometer. Low blood glucose levels will lead to altered mental status.
  • Start an IV of normal saline or Lactated Ringer's per protocol.
  • Monitor the cardiac rhythm.
  • Administer D-50 (Dextrose 50%) if indicated by the blood glucose check (per protocol), this will reverse the hypoglycemia and possibly save the life of the hypoglycemic patient.

An immediate response to the administration of glucose is a common occurrence if hypoglycemia is the cause of unconsciousness. Checking the blood glucose level should be done prior to intubating the patient to avoid having a conscious intubated patient to deal with as mentioned earlier.

An alcoholic patient can benefit from the administration of glucose as well. Many alcoholics are hypoglycemic.

Adult and pediatric doses of D-50 (Dextrose 50%) are as follows:

  • Adult - 50 ml (25 gm) IVP. May be repeated as necessary.
  • Pediatric- 0.5 - 1.0 gm/kg IVP. You will first need to dilute D-50 at a ratio of 1:1 with sterile water or normal saline to make the concentration of the solution D-25 (dextrose 25%).

For patients suspected of a narcotic overdose, administration of naloxone is indicated. Naloxone is a narcotic antagonist and can reverse the effects of narcotics and synthetic narcotic agents. Darvon overdoses may require larger than normal doses of naloxone. Field doses of naloxone are as follows:

  • Adult - 1 - 2 mg IV, ET, IM, or SQ. May be followed at two to three minute intervals for two to three doses if the patient fails to respond.
  • Pediatric - 0.01 mg/kg for a maximum dose = 0.8 mg IV, ET. If there is no response in ten minutes, give 2 mg.

Suspected alcoholics may benefit from the administration of thiamine. Thiamine is needed for the body to make use of glucose. Alcoholics are notoriously thiamine deficient. Administer 100 mg IV. The brain is extremely sensitive to thiamine deficiency.

The common field name for the previously mentioned medications administered to the unresponsive patient is the "coma cocktail".

Chronic Alcoholism

The chronic ingestion of alcohol interferes with the intake and absorption of thiamine. This deficiency can lead to Wernicke's Syndrome or Korsakoff's Psychosis. Wernicke's Syndrome is an acute, reversible, condition characterized by loss of memory, disorientation, eye muscle weakness, and mental disorders. Korsakoff's Psychosis is an even greater concern due to the fact that it tends to be irreversible. This condition is characterized by disorientation, muttering delirium, insomnia, hallucinations, and delirium. Symptoms include extremity pain, bilateral foot drop, bilateral wrist drop (in rare cases), and pain on pressure over the long nerves.

Intracranial Pressure

Most closed head injuries are likely to produce increased intracranial pressure. When a head injury is suspected, the patient should be hyperventilated to help constrict blood vessels and therefore minimizing brain swelling. The administration of a steroid such as dexamethasone (Decadron) may also help reduce cerebral edema. Many EMS systems also employ the use of an osmotic diuretic such as mannitol (Osmitrol) which causes diuresis, eliminating fluid from the intravascular space through the kidneys. It is possible that mannitol may also cause an oncotic effect which causes a fluid shift from brain tissue to the circulation of the brain thereby reducing brain swelling. Always follow your local protocols and medical direction regarding the use of any field administered medication.

Seizure

Seizures are caused by abnormal electrical activity in the brain. The highest incidence of seizures among the population occurs in children under 5 years of age and is associated with high fevers (febrile seizures). Seizures may be caused by multiple factors such as:

  • Stroke
  • Head trauma
  • Fever
  • Toxins
  • Drugs
  • Hypoxia
  • Hypoglycemia
  • Infection
  • Metabolic abnormalities
  • Tumors
  • Vascular disorders
  • Eclampsia

Determining the actual cause in the field is of less importance than managing the complications, and realizing whether the seizure is reversible. Seizures that occur persistently (with the exception of those that arise from alcohol withdrawal and other avoidable circumstances) are called epilepsy.

Types of Seizures

Generalized Seizures

The term "generalized seizure" refers to the fact that there is no definable origin in the brain. Petit mal and grand mal seizures are generalized seizures.

Petit mal (absent) seizures most often occur in children between the ages of four and twelve. There is a brief lapse of consciousness, often no motor activity, sometimes eye blinking, lip movements, or some clonic activity. Usually petit mal seizures last 15 seconds or less. During this time the patient is unaware of their surroundings then they return to a normal state of awareness. This type of seizure activity usually diminishes with age but some progress to grand mal seizures.

Grand mal (tonic/clonic) seizures are common and are often preceded by an aura (olfactory or auditory sensation) which is recognized by the patient who perceives this as a warning of an impending seizure. The grand mal seizure is characterized by a sudden loss of consciousness, a loss of organized muscle tone, then a tonic phase in which there is various muscle activity (flexion, extension), and periods of apnea.

Tongue biting and incontinence are common occurrences. The tonic phase should be short-lived (a few seconds) and then the patient goes into the bilateral clonic phase. This is where the alternating rigidity and relaxation of muscles occurs and lasts up to several minutes. During this phase the autonomic nervous system is kicking in and working overtime producing hyperventilation, salivation, and tachycardia. After the clonic phase, the patient usually becomes drowsy or is unconscious from minutes to hours. Once the patient regains consciousness they are generally confused, tired, and may exhibit transient neurological deficits. This is the postictal phase.

Status Epilepticus

When the grand mal seizure is prolonged or recurs prior to the patient regaining consciousness it is known as status epilepticus. This is a continuous seizure, lasting 30 minutes or more, or a recurrent seizure in which the patient fails to regain consciousness. This type of seizure is considered a true emergency. It can result in permanent neurological damage, respiratory arrest, and death. It may also result in brain damage, broken bones, necrosis of heart muscle, severe dehydration, and aspiration. This is most commonly caused by adults who fail to take their prescribed medication.

Partial Seizures

Partial seizures differ from generalized seizures in that the focus is from an identifiable cortical lesion. The partial seizure may be classified as simple or complex. Partial seizures generally manifest themselves in clonic activity specific to one area of the body such as one arm or one leg, or one hand or one side of the face.

Simple seizures result in a tingling or numbness of a body part or abnormal olfactory, auditory, visual, or taste symptoms. Patients with partial seizures do not usually lose consciousness. The seizure may, however, lead to a tonic-clonic seizure. Partial seizures that spread in an orderly fashion to surrounding areas of the body are known as Jacksonian Seizures.

Complex partial seizures originate in the temporal lobe of the brain and usually manifest themselves as changes in behavior. In a classic complex partial seizure the patient experiences an aura, that is followed by an abnormal repetitive motor behavior such as mouth movements, swallowing, or chewing. The patient is unaware of the activity and the seizure is typically very brief (less than one minute). The patient regains normal mental status quickly. This type of seizure may also progress to tonic-clonic seizures.

Assessment

Many times, when you arrive on the scene of a patient who has been reported having a seizure, you will be arriving during the postictal phase. You will need to question bystanders who were witnesses to the event if possible in order to gather accurate information regarding the onset of the seizure if in fact it was a seizure and not just a fainting spell (syncope).

History

There are many problems that may mimic a seizure including:

  • Migraine headaches
  • Hypoglycemia
  • Cardiac problems
  • Drug abuse

Hypotension

 To the general public, many of these problems seem to look like a seizure. Stiffness of the extremities can be caused by hyperventilation, meningitis, intracranial bleeding, or medication usage. When trying to ascertain a history, try to include the following:

  • History of seizures
  • Recent history of head trauma
  • Alcohol or drug use
  • History of diabetes
  • History of headache, fever, or stiff neck
  • History of heart disease or CVA
  • Current medications, especially anti-convulsant drugs such as Dilantin (phenytoin) or phenobarbital

Distinguishing between other medical problems and a true seizure is important in guiding your patient care. Syncope results from insufficient blood supply to the brain, usually resulting from low cardiac output, insufficient blood volume or dilation of peripheral blood vessels. Some syncope patients will exhibit a short period of seizure-like activity but will not experience a postictal phase. The most common causes of syncopal episodes are vasovagal activity, stress, cardiac disease, or dysrhythmias.

Management

Take the following steps when examining a seizure patient:

  • Look for any signs of head trauma or injury to the lips or tongue.
  • Be sure to monitor the ECG
  • Look for signs of drug and alcohol abuse.

Usually the seizure patient will not need a great deal of treatment. Support for family members is important. Provide supplemental oxygen and position the patient to prevent aspiration. Maintain body temperature and do the following:

  • Maintain airway
  • Administer oxygen
  • Start an IV with normal saline or Lactated Ringer's per protocol. Dextrose solutions may interfere with medications such as phenytoin (Dilantin).
  • Check the blood glucose level
  • Never restrain the patient
  • Position the patient on their side after the tonic-clonic phase
  • Have suction available and use it if needed
  • Monitor the ECG
  • Transport in a supine or lateral recumbent position

Status Epilepticus

Management

The most valuable intervention is assuring a patent airway. Assist ventilations with a bag-valve-mask and 100% oxygen. After securing the airway take the following steps:

  • Start an IV of normal saline or Lactated Ringer's per protocol
  • Monitor the ECG
  • If hypoglycemia is suspected, administer 25 gm of D50 (Dextrose 50%) IVP
  • For pediatric patients, administer 0.5 - 1.0 gm/kg of D25 per protocol
  • Administer 5 - 10 mg diazepam IVP for an adult per protocol
  • For pediatric seizures, administer diazepam 0.2 - 0.5 mg/kg per protocol

Cerebrovascular Accident (CVA, Stroke)

Stroke is caused by a sudden interruption of blood flow to the brain. Stroke affects more than 500,000 Americans every year. Stroke is the third leading cause of death in the U.S. and 10 - 15 % of those who suffer from a stroke die within 30 days. Survivors are often left severely debilitated. The following risk factors contribute significantly to the likelihood of a person suffering a stroke:

  • Hypertension
  • Diabetes
  • Atherosclerosis
  • Hyperlipidemia
  • Polycythemia
  • Cardiac disease

Patients suffering a stroke tend to experience a sudden loss of consciousness followed by paralysis. This can be caused by a hemorrhage into the brain tissue, an embolus in a cerebral blood vessel or a thrombus formation, occluding arterial blood supply to the brain. Cardiovascular accidents can be categorized as follows:

  • Infarction - The same mechanism as a myocardial infarction in that the blood supply to a certain area of the brain is inadequate. Necrosis of the nervous tissue develops. Infarctions can be due to an embolism or atherosclerosis.
  • Hemorrhage - This type of cardiovascular accident is often sudden and is characterized by a severe headache and stiff neck. Intracranial hemorrhage tends to occur in the hypertensive patient when a small blood vessel deep within the brain ruptures. Subarachnoid hemorrhages usually result from head trauma or aneurysm. Aneurysms tend to be on the surface and can hemorrhage into the subarachnoid space or the brain tissue itself.

When brain tissue is infarcted, the tissue that is affected will tend to swell causing further damage to surrounding tissue. If the swelling is severe enough, it may cause the brain to herniate.

Hemorrhage inside the brain tends to tear and separate adjoining tissue. Blood released into cavities that contain spinal fluid may paralyze vital brain centers. If the hemorrhage results in impaired drainage of spinal fluid, it will generally cause a rise in intracranial pressure. This may result in herniation of brain tissue through the foramen magnum, the narrow opening in the skull in which the spinal cord enters and connects to the brain via the brainstem.

Pathophysiology

There are four major vessels which supply the brain with blood. Two carotid arteries which provide about 80% of the blood flow and two vertebral arteries which join at the basilar artery supplying the remaining 20%. The two systems are interconnected mainly at the Circle of Willis, as well as in a few other places. The stoppage of blood flow distal to this area could result in ischemia and infarction. The sudden stoppage of circulation to a portion of the brain that is a result of blood vessel occlusion or hemorrhage cannot be corrected by the normal autoregulatory functions of cerebral blood vessels which can ordinarily constrict or dilate to preserve perfusion in the event of hypotension. Perfusion of the brain is also regulated at the arteriolar level which use levels of glucose and oxygen as components of regulation (ischemia and acidosis are profound vasodilators). Uncorrected ischemia leads to neuronal dysfunction and eventual death.

Clinical Presentation of Stroke

The area of the brain being affected has a bearing on the symptoms experienced by the patient suffering from stroke. Commonly affected areas are speech, motor function, and sensory functions. Pupils may be affected with the larger pupil indicating the affected side of the brain. The patient may become unconscious. Often one side of the body will become paralyzed. The skin can become cool and clammy and there may be speech disturbances or aphasia.

Transient Ischemic Attacks (TIA's)

Transient ischemic attacks are sometimes caused by small emboli that can temporarily interfere with blood supply to the brain. This temporary occlusion can produce signs and symptoms of stroke. The attack can last from a few minutes to several hours. Generally, the patient recovers fully with no evidence of permanent neurological damage. This can be a precursor to a full blown stroke. The TIA is often acute with the patient experiencing lightheadedness or dizziness. The symptoms will depend on the area of the brain being affected.

The following conditions are commonly associated with a TIA:

  • Blindness in one eye
  • Paralysis on one side (hemiparesis)
  • Inability to recognize by touch
  • Staggering
  • Difficulty swallowing (dysphagia)
  • Weakness on one side
  • Inability to speak (aphasia)
  • Dizziness
  • Numbness
  • Paresthesia (tingling or "pins and needles" sensation)

Carotid artery disease is perhaps the most common cause of transient ischemic attacks. Other causes can be hypertension, over-medication of anti-hypertensive agents, or cerebrovascular spasms.

When assessing the patient who may be experiencing a TIA, collect information on, or take note of the following:

  • Previous neurological symptoms
  • Initial symptoms and the progression of those symptoms
  • Precipitating factors
  • Dizziness
  • Changes in mental status
  • History of hypertension, sickle cell disease, cardiac disease, previous TIA's or CVA's
  • Palpitations of the heart

During the head-to-toe survey look for the following:

  • Hemiparesis noted during the neurological exam of the extremities
  • Unilateral facial droop
  • Speech disturbances
  • Confusion and agitation
  • Uncoordinated motor movements
  • Vision problems
  • Excessive laughing or crying

Coma

Management

Managing the patient suspected of experiencing a TIA or stroke should include keeping the patient in a supine position with the head elevated about 15 degrees to allow for drainage of venous blood from the brain. The management of the stroke patient is largely supportive and aimed at preventing secondary problems such as hypoxia, hypotension, and acidosis. Airway maintenance and ventilatory support with supplemental oxygen is extremely important.

Management of the stroke patient should include:

  • Initiate an IV of Lactated Ringer's or normal saline per protocol.
  • Draw a blood sample for lab analysis
  • Check the blood glucose level and administer 50% dextrose if indicated.
  • Monitor the cardiac rhythm
  • Protect paralyzed extremities

Degenerative and Congenital Neurological Disorders

There are numerous degenerative and congenital disorders of the nervous system. Following is a discussion of some of the disorders you may encounter in the field.

Parkinson's Disease

Parkinson's disease is a progressive disorder of the central nervous system that typically affects people around the age of 60. The underlying cause is unknown.

Pathological changes occur in the substantia nigra, which is a region of darkly pigmented nuclei in the basal ganglia of the midbrain that controls subconscious muscle activity. The dopamine-containing neurons in the substantia nigra degenerate resulting in an imbalance of neurotransmitter activity in the brain. The brain has too little dopamine and too much acetylcholine.

Involuntary muscle contractions interfere with voluntary movement. A common symptom of Parkinson's disease is shaking of the hands, or tremor. Some muscles may contract continuously causing rigidity. This is commonly seen in the facial muscles causing a mask-like effect. The patient has a wide-eyed, unblinking stare, slightly open mouth, and uncontrolled drooling. Other symptoms are a decreased range of motion, impaired walking, and difficulty with speech.

Parkinson's disease has no cure to date but several treatments are available. Many patients are prescribed a combination of the two drugs levodopa and carbidopa. Levodopa elevates dopamine levels in the body and carbidopa inhibits the formation of dopamine outside the brain, reducing the undesirable cardiac and other systemic effects of dopamine. Other medications that have had some success are monoamine oxidase (MAO) inhibitors and anticholinergics. A controversial treatment that has had positive results is transplantation fetal tissue into the basal ganglia of patients with severe Parkinson's disease.

Poliomyelitis

Poliomyelitis, or simply polio, is caused by a virus called poliovirus. The onset of the disease is marked by fever, severe headache, stiff neck and back, deep muscle pain and weakness, and loss of reflexes. In serious cases, paralysis may occur due to destruction of cell bodies of motor neurons in the spinal cord and cranial nerves. The level of paralysis depends on the extent of viral infection. Polio can cause death from respiratory failure or heart failure if the virus invades the brainstem.

The polio vaccine has virtually eradicated polio in the U.S. However, you may encounter patients who contracted polio prior to the development of the polio vaccine or patients that were born outside the U.S.

Spina Bifida

Spina bifida is a neural tube defect associated with folic acid deficiency just prior to and during pregnancy. It is a congenital defect of the vertebral column in which the laminae of the vertebrae fail to unite at the midline. There are three types of spina bifida: spina bifida occulta, meningocele, and myelomeningocele.

Spina bifida occulta is an opening in one or more of the vertebrae without damage to the spinal column. Many people may have this condition and not be aware of it. The second condition, meningocele, is a conditon in which the meninges push through the opening in the vertebrae in a sac called the "meningocele". The spinal cord remains intact and this defect can be surgically repaired without affecting nerve pathways.

The most serious form of spina bifida is termed myelomeningocele. The meninges and the spinal cord protrude from the spinal column. Surgery is required to repair this defect, but the child with this condition will most likely have lasting effects. Protrusion of the meninges and spinal cord can cause paralysis, loss of bladder control, and absence of reflexes. Hydrocephalus, which is an accumulation of fluid in the brain, is common. A shunt, or drain, can be inserted to relieve the pressure from the accumulated fluid. These children may have learning disabilities associated with hydrocephalus, require training to overcome problems with bladder and bowel functions, and may require crutches or wheelchairs for mobility.

Spina bifida can be diagnosed prenatally through a blood test, sonography, or amniocentesis.

Multiple Sclerosis

Multiple sclerosis is an inflammatory disorder that causes progressive destruction of the myelin sheaths in the central nervous system. The etiology is unknown, but it is thought to be an autoimmune disorder triggered by a viral infection. The myelin sheaths deteriorate into scleroses, which are hardened scars or plaques, in multiple regions, hence the name multiple sclerosis.

The first symptoms, muscular weakness, abnormal sensations, and double vision (diplopia), usually appear in early adulthood. The patient then goes into a period of remission, but the attacks reappear later in adulthood and recur about every one or two years. The result is a progressive loss of function and can leave the patient debilitated. No cure has been found at this time.

Muscular Dystrophy

Muscular dystrophy is an inherited muscle-destroying disease. It causes degeneration of individual muscle fibers which leads to progressive atrophy of skeletal muscle. The voluntary muscles are affected, not the internal muscles such as the diaphragm. The person with muscular dystrophy will suffer from progressive muscle weakness and will eventually become debilitated.

The most common form of muscular dystrophy is Duchenne muscular dystrophy, which affects mostly boys and the onset is between three and five years of age. No cure has been found at this time despite intense research about the disease.

Management

Management of degenerative and congenital neurological disorders depends on the signs and symptoms the patient is exhibiting. As with any patient, assess the ABC's, constantly monitor the patient's airway for patency, monitor vital signs, initiate therapy as needed for the patient's condition, and transport to the nearest appropriate facility.