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Nervous System Emergencies Nervous System A & P Nervous System Basics The body’s control system Exerts control through electrochemical impulses transmitted through nerves Three subdivisions Central nervous system (brain and spinal cord) Peripheral nervous system (cranial, peripheral nerves) Autonomic nervous system (sympathetic, parasympathetic) Nervous System A & P A & P of CNS (brain and spinal cord) Neuron-nerve cell; fundamental component of the nervous system Cell body contains nucleus Dendrites carry nervous impulses to cell body Axons transmit nerve impulses away from cell body Nervous System A & P A & P of CNS (brain and spinal cord) Transmission of impulses in the nervous system At rest, neuron is positively charged outside, negatively charged inside When stimulated, sodium enters cell, potassium rapidly leaves cell Activity produces positive charge, called action potential, at entry site Nervous System A & P Overview A & P of CNS (brain and spinal cord) Transmission of impulses in the nervous system (cont.) Action potential transmitted down neuron to meet other neurons at junctions called synapses Axon releases neurotransmitter (acetylcholine or norepinephrine) that transports impulses across synapse and stimulates connecting nerve Nervous System A & P Overview Protective structures of the CNS Mostly protected by body structures (skull, spinal column) Also covered by membranes - meninges (pia, arachnoid, dura) Brain and spinal cord also bathed in cerebrospinal fluid (CSF) Nervous System A & P Overview The brain Cerebrum Diencephalon Mesencephalon Pons Medulla Oblongata Cerebellum Nervous System A & P Overview Cerebrum Two hemispheres joined by corpus callosum Governs all sensory and motor functions Responsible for language, learning, analysis, memory Cerebral cortex is outermost layer Nervous System A & P Overview Diencephalon Superiormost portion of brain stem Contains thalamus, hypothalamus, limbic system Responsible for involuntary actions Major role in regulating autonomic nervous system Nervous System A & P Overview Mesencephalon Midbrain-located between mesencephalon and pons Responsible for motor coordination and eye movement Nervous System A & P Overview Pons Located between midbrain and medulla Contains connections between the brain and spinal cord Nervous System A & P Overview Medulla Oblongata Located between pons and spinal cord Marks division between brain and spinal cord Controls respirations, cardiac function , vasomotor activity Nervous System A & P Overview Cerebellum Located in posterior fossa of cranial cavity Coordinates fine motor movement, posture, equilibrium, muscle tone Nervous System A & P Overview Areas of Specialization Speech-temporal lobe Vision-occipital lobe Personality-frontal lobes Balance and coordination-cerebellum Sensory-parietal lobes Motor-frontal lobes Nervous System A & P Overview Vascular supply to brain Supplied by two systems: carotid system and vertebrobasilar system Both join at the circle of Willis before entering brain Interruption of one system will not seriously affect brain perfusion Venous drainage through venous sinuses and internal jugular veins Nervous System A & P Overview Spinal Cord 17-18 inches long Leaves the brain through the foramen magnum Conducts impulses to peripheral nervous system Conducts sensory impulses to the brain and has reflex arc capability Nervous System A & P Overview Spinal Cord (cont.) Has 31 pairs of nerve fibers Dorsal roots contain afferent fibers (body to brain) Ventral roots contain efferent fibers (brain to body) Nerve fibers innovate corresponding body areas called dermatones Nervous System A & P Overview A & P of the peripheral nervous system Basic information Consists of cranial and peripheral nerves Has both voluntary and involuntary components Nervous System A & P Overview A & P of the peripheral nervous system Categories of the peripheral nerves Somatic motor-carry impulses to skeletal muscles Visceral sensory-transmit sensations from visceral organs (e.g., full bladder need to defecate, etc.) Somatic sensory-transmit sensations of touch, pressure, pain, temperature, position Visceral motor-supply nerves to visceral glands and organs Nervous System A & P Overview Autonomic nervous system Responsible for unconscious control of body functions Made up of two antagonistic, but normally balanced parts Sympathetic nervous system controls stress response Parasympathetic nervous system controls custodial (vegetative) functions Assessment of the Neurological System Primary Assessment First check for responsiveness Place emphasis on airway maintenance and cervical spine stabilization With unconscious patients assume cervical spinal injury Use modified jaw thrust maneuvers Remain alert for possibility of respiratory arrest Assessment of the Nervous System Secondary Assessment History Determine trauma vs medical etiology If trauma When did incident occur Mechanism of injury Any loss of consciousness Chief complaint Complicating factors Assessment of the Nervous System Secondary Assessment (cont.) History (cont.) If nontrauma Chief complaint History of present illness Pertinent underlying medical problems (cardiac disease, hypertension, diabetes, seizures) Environmental clues (medications, Medic-alert ID, alcohol or drug bottles) Assessment of the Nervous System Head to toe survey Pupils Check eye movement and pupil reaction Early indicators of increasing ICP Cardinal positions of gaze Fixed, midsize pupils-midbrain Pinpoint pupils, barely reactive-pons Unilateral fixed and dilated pupil-third nerve Fixed or asymmetric pupils-structural lesions Nonreative pupils-toxic/metabolic states Assessment of the Nervous System Head to toe survey (cont.) Pupils (cont.) Extraocular movements Disconjugate gaze-structural brainstem lesion Doll’s eyes-brainstem dysfunction Assessment of the Nervous System Head to toe survey (cont.) Respiratory derangements common with CNS illness or injury Cheyne Stokes respiration-period of apnea followed by increasing depth and frequency of respirations Central neurogenic hyperventilation-rapid, deep, noisy respirations; lesion in CNS Ataxic respirations-ineffective thoracic muscular coordination due to CNS damage Assessment of the Nervous System Head to toe survey (cont.) Respiratory derangements common with CNS illness or injury (cont.) Apneustic respirations-prolonged inspiration unrelieved by expiration attempts; damage to upper pons Diaphragmatic breathing-caused by intercostal muscle dysfunction Assessment of the Nervous System Spinal Evaluation-document loss of motor function or sensation Evaluate for pain and tenderness Observe for bruises Observe for deformity Check for motor, sensory and position in each extremity and bilateral grip strength Determine response to pain Note any incontinence Assessment of the Nervous System Vital signs that characterize CNS injury Increased blood pressure Decreased pulse Decreased respirations Increased temperature Assessment of the Nervous System Neurological Evaluation - provides baseline neurological findings for later comparison/contrast Determine level of consciousness AVPU during primary survey Note sensation and motor function in extremities Asymmetry-structural lesions Abnormal posturing Flaccid paralysis-spinal cord injury Assessment of the Nervous System Glascow Coma Scale Evaluates coma patient with CNS injury by monitoring Eye openings Verbal response Motor response Nervous System Emergencies Altered mental status-hallmark of CNS illness or injury Basic mechanisms that can produce altered mental status Structural lesions Toxic-metabolic states Nervous System Emergencies Common causes of altered mental status Structural Trauma Brain tumor Epilepsy Intracranial hemorrhage Other space-occupying lesions Nervous System Emergencies Common causes of altered mental status Metabolic Anoxia Hypoglycemia Diabetic ketoacidosis Hepatic failure Renal failure Thiamine deficiency Nervous System Emergencies Common causes of altered mental status Drugs Barbiturates Narcotics Hallucinogens Depressants Nervous System Emergencies Common causes of altered mental status Cardiovascular Hypertensive encephalopathy Shock Anaphylaxis Dysrhythmias Cardiac arrest CVA Nervous System Emergencies Common causes of altered mental status Respiratory COPD Toxic gas inhalation Infectious Encephalitis Meningitis Nervous System Emergencies Primary Assessment Special attention to the airway and c-spine Consider AEIOU TIPS mnemonic Early intubation Nervous System Emergencies Secondary Assessment History Length of alteration in mental status Onset History of recent head trauma patient under medical care Alcohol or drug use Preceding symptoms or complaints Any medications Medic-Alert tags Nervous System Emergencies Secondary Assessment (cont.) Physical exam-should include breathing, response to stimuli, eye response, pupil response, being particularly alert in suspected CNS illness or injury cases Pupillary reflexes-fixed, dilated, or asymmetric pupils Extraocular movements-dysconjugate gaze Nervous System Emergencies Secondary Assessment (cont.) Physical exam-should include breathing, response to stimuli, eye response, pupil response, being particularly alert in suspected CNS illness or injury cases Motor findings-asymmetry, decorticate or decebrate posturing, flaccid paralysis Respiratory patterns Vital signs-hypertension, bradycardia, unusual body temperature Nervous System Emergencies Management Immobilization of the cervical spine Assure patency and adequate breathing Draw venous blood sample, check blood sugar with glucometer or chem strip IV 5% D5W at TKO rate; related NS or LR if trauma Cardiac monitor Nervous System Emergencies Drug considerations 50mL of 50% dextrose (25 grams) IV to correct hypoglycemia Naloxone 1-2 mg IV to reverse narcotic overdose Thiamine 100mg IV to correct thiamine deficiency and allow glucose metabolism Mannitol 25g IV to reduce ICP Decadron 4-24 mg IV to reduce cerebral edema Nervous System Emergencies Management with chronic alcoholism Many have thiamine deficiency Wernicke’s syndrome-memory loss, disorientation Korsakoff’s psychosis-disorientation,m muttering delirium, insomnia, delusions painful extremities, bilateral foot drop, pain on pressure over long nerves These patients should receive 100 mg Thiamine IV or IM Nervous System Emergencies Management with ICP Hyperventilate patient Decadron 4-24 mg IV to reduce cerebral edema Mannitol 25g IV to cause an osmotic diuresis Nervous System Emergencies Seizures Pathophysiology of seizures Massive electrical discharge of one or more groups of neurons in the brain Can be general or partial Generalized seizures-grand mal and petit mal Partial seizures-simple or complex (psychomotor) Nervous System Emergencies Seizures (cont.) Causes of seizures Stressors such as hypoxia, sudden elevation in temperature, or hypoglycemia in healthy persons Structural diseases such as tumors, head trauma, eclampsia, vascular disorders Idiopathic epilepsy is the most common cause Nervous System Emergencies Seizures (cont.) Types of Seizures Grand Mal-generalized motor seizure Produces loss of consciousness from brain hypoxia Causes uncontrollable tonic/clonic movements of extremities Disrupts respirations, producing cyanosis Often lead to frothing, incontinence, mental confusion Coma or drowsiness follows (postical period) Nervous System Emergencies Seizures (cont.) Grand-mal (progression) Aura-subjective sensation preceding seizure May be psychic (déjà vu) May be sensory (a noise, sight, sound, odor) Loss of consciousness Tonic phase-continuous motor tension and contraction of muscles Nervous System Emergencies Seizures (cont.) Grand-mal (progression cont.) Hypertonic phase-extreme muscular rigidity, hyperextension of the back Clonic phase-extreme muscular rigid Nervous System Emergencies Seizures (cont.) Grand-mal (progression cont.) Post-seizure coma Postictal period-patient awakens confused, fatigued with some neurological deficits Nervous System Emergencies Seizures (cont.) Focal motor seizures Characterized by dysfunction of one area of the body Caused by electrical discharge form one part of the brain Begin as localized tonic/clonic movements; can spread and appear s generalized Nervous System Emergencies Seizures (cont.) Psychomotor (temporal lobe) seizures Characterized by distinctive pre-seizure aura Focal seizures lasting 1-2 minutes Patient experiences loss of contact with surroundings Patient may be confused, purposeless, or may show change in personality or rage abruptly Nervous System Emergencies Seizures (cont.) Petit mal seizures Generalized seizures with 10-30 second loss of consciousness Patient may stare and flutter eyelids Observers may be unaware of seizure Nervous System Emergencies Seizures (cont.) Hysterical seizures Psychological disorders Patient presents with sharp and bizarre movements Curt commands can curtail seizure No postical period Use of aromatic ammonia may differentiate hysterical from true seizure Nervous System Emergencies Assessment rule out other causes of coma Obtain history including: History of seizure Alcohol/drug abuse Current medications Recent history of head trauma Description of seizure Past medical history (diabetes, cardiac, strokes) Differentiate true seizure vs. syncope Nervous System Emergencies Management Protect patient from self-harm; do not restrain Maintain airway Administer oxygen Establish IV access Determine blood glucose; D50W if needed Protect body temperature position patient on side after tonic/clonic phase Nervous System Emergencies Management (cont.) Suction if required Monitor cardiac rhythm Provide quiet rest, reassuring atmosphere Transport in supine or lateral recumbent position Nervous System Emergencies Status Epilepticus Description Series of two or more seizures without lucid period Most common cause is failure to take anticonvulsant medications Can lead to brain injury from anoxia Nervous System Emergencies Status Epilepticus (cont.) Management Establish and protect airway Assist ventilations with 100% oxygen Establish IV access with NS TKO Monitor cardiac rhythm Administer 50% dextrose 25gm IV Administer diazepam 5-10 mg IV Nervous System Emergencies Stroke (cerebrovascular accident - CVA) Pathophysiology injury or death to brain tissue from interruption of blood Can by caused by ischemic or hemorrhagic lesions commonly secondary to atherosclerosis or hypertension Sudden loss of consciousness followed by paralysis which may be caused by hemorrhage, embolism or thrombus Nervous System Emergencies Strokes (cont.) Categories Infarction of stroke Inadequate blood supply to limited prtion of the brain caused by embolism or blood vessel occlusion usually due to thrombus Hemorrhage Intracerebral or subarachnoid bleeding Marked by sudden onset of headache and stiff neck Can cause increased intracranial pressure Nervous System Emergencies Strokes (cont.) Clinical presentation of a stroke Symptoms depend on area of brain injured Motor, speech, and sensory centers most commonly affected Onset of symptoms is acute and may include: Unconsciousness Stertorous breathing Unequal pupils Unilateral paralysis Speech disturbances Nervous System Emergencies Strokes (cont.) Distinguishing CVA from transient ischemic attacks (TIA’s) Temporary stroke symptoms Usually caused by small emboli Can last several minutes to hours No evidence of neurological deficient after attack Abrupt onset with symptoms depending on area of brain affected Nervous System Emergencies Strokes (cont.) Symptoms Monocular blindness Hemiplegia Inability to recognize by touch Staggering Difficulty in swallowing, aphasia Hemiparesis Dizziness Numbness, paresthesia Nervous System Emergencies Strokes (cont.) History - Determine: Previous neurological symptoms Initial symptoms and their progression Chanbes in mental status Precipitating factors Dizziness Palpitations History of hypertension, cardiac disease, sickle cell disease, previous TIA or stroke Nervous System Emergencies Strokes (cont.) Physical Exam - Be alert for: Hemiparesis, hemiplegia Unilateral facial droop Speech disturbances Gait problems Altered mental status Vision problems Nervous System Emergencies Strokes (cont.) Management of CVA and TIA Maintain patient supine with 15 degree head elevation to maximize venous drainage Maintain c-spine integrity if trauma suspected Maintain a patent airway, assisting ventilation PRN Administer oxygen, hyperventilation if patient unresponsive Draw venous blood sample and test for blood sugar Nervous System Emergencies Strokes (cont.) Management Start IV with NS or LR TKO Monitor cardiac rhythm If patient hypoglycemic, give D50W Protect paralyzed extremities Reassure patient and transport quietly to hospital Nervous System Emergencies Judy Dyke, RN, NREMT-P Rogers State University Paramedic Technology Program
