Nervous System Emergencies

1. Nervous System Emergencies

2. 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)

3. 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

4. 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

5. 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

6. 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)

7. Nervous System A & P Overview • The brain • Cerebrum • Diencephalon • Mesencephalon • Pons • Medulla Oblongata • Cerebellum

8. 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

9. 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

10. Nervous System A & P Overview • Mesencephalon • Midbrain-located between mesencephalon and pons • Responsible for motor coordination and eye movement

11. Nervous System A & P Overview • Pons • Located between midbrain and medulla • Contains connections between the brain and spinal cord

12. 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

13. Nervous System A & P Overview • Cerebellum • Located in posterior fossa of cranial cavity • Coordinates fine motor movement, posture, equilibrium, muscle tone

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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

23. 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)

24. 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

25. Assessment of the Nervous System • Head to toe survey (cont.) • Pupils (cont.) • Extraocular movements • Disconjugate gaze-structural brainstem lesion • Doll’s eyes-brainstem dysfunction

26. 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

27. 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

28. 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

29. Assessment of the Nervous System • Vital signs that characterize CNS injury • Increased blood pressure • Decreased pulse • Decreased respirations • Increased temperature

30. 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

31. Assessment of the Nervous System • Glascow Coma Scale • Evaluates coma patient with CNS injury by monitoring • Eye openings • Verbal response • Motor response

32. 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

33. Nervous System Emergencies • Common causes of altered mental status • Structural • Trauma • Brain tumor • Epilepsy • Intracranial hemorrhage • Other space-occupying lesions

34. Nervous System Emergencies • Common causes of altered mental status • Metabolic • Anoxia • Hypoglycemia • Diabetic ketoacidosis • Hepatic failure • Renal failure • Thiamine deficiency

35. Nervous System Emergencies • Common causes of altered mental status • Drugs • Barbiturates • Narcotics • Hallucinogens • Depressants

36. Nervous System Emergencies • Common causes of altered mental status • Cardiovascular • Hypertensive encephalopathy • Shock • Anaphylaxis • Dysrhythmias • Cardiac arrest • CVA

37. Nervous System Emergencies • Common causes of altered mental status • Respiratory • COPD • Toxic gas inhalation • Infectious • Encephalitis • Meningitis

38. Nervous System Emergencies • Primary Assessment • Special attention to the airway and c-spine • Consider AEIOU TIPS mnemonic • Early intubation

39. 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

40. 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

41. 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

42. 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

43. 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

44. 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

45. 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

46. 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)

47. 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

48. 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)

49. 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

50. Nervous System Emergencies • Seizures (cont.) • Grand-mal (progressioncont.) • Hypertonic phase-extreme muscular rigidity, hyperextension of the back • Clonic phase-extreme muscular rigid