Neuro- MedSurg Notes PDF

NERVOUS SYSTEM  Group Members: Alap-ap, Nazzar Jul Cirunay, Jeyza Bongon, Princess Jel Ortiz, Alexis Leigh Ebrole, Mary Jenelle Sanchez, Jerica Gaye Topics to be Discussed: Assessment of Neurologic Functions Cerebrovascular Accident Cranial and Peripheral Nerves Conditions...

NERVOUS SYSTEM  Group Members: Alap-ap, Nazzar Jul Cirunay, Jeyza Bongon, Princess Jel Ortiz, Alexis Leigh Ebrole, Mary Jenelle Sanchez, Jerica Gaye Topics to be Discussed: Assessment of Neurologic Functions Cerebrovascular Accident Cranial and Peripheral Nerves Conditions Multiorgan Failure Assessment of the NEUROLOGIC FUNCTIONS  Anatomic and Physiologic Nervous System Overview 2 divisions: (1) Central Nervous System; (2) Peripheral Nervous system Functions: control all motor, sensory, autonomic, cognitive, and behavioral activities  Anatomic and Physiologic Cell of the Overview Nervous System NEURON - the basic functional unit of the brain - composed of dendrites and an axon. DENDRITE - branch-type structure with synapses (receiving) AXON - long projection (sending)  Anatomic and Physiologic Cell of the Overview Nervous System GANGLIA or NUCLEI - nerve cell bodies in clusters CENTER - cluster of cell bodies with same function NEUROGLIAL CELLS - a nerve cell which supports, protect and nourish neurons  Anatomic and Physiologic Neurotransmitters Overview messages from neuron-> another neuron -> specific tissue to potentiate, terminate, or modulate a specific action may excite or inhibit the target cell's activity very crucial in neurologic functions and play roles in neurologic disorders  Anatomic and Physiologic Neurotransmitters Overview Receptor Types: DIRECT - "inotropic" ; linked to ion channels; allow passage of ions when opened - rapid-acting INDIRECT RECEPTORS - affect metabolic processes in the cell - take from seconds to hours to occur.  Anatomic and Physiologic Neurotransmitters Overview Examples: Central Nervous System (1) BRAIN Cerebrum Cerebellum Brain Stem (2) SPINAL CORD PARTS OF THE BRAIN  Parts of the Brain CERREBRUM two hemispheres: Right and Left Gray matter -outermost; billions of neurons White matter - innermost; nerve fibers and neuroglia Each hemisphere divided into 2 pairs of: - frontal lobes - parietal lobes - temporal lobes - occipital lobes  Parts of the Brain CERREBRUM FRONTAL LOBE - largest lobe - concentration, abstract thought, information storage or memory, and motor function - Broca’s area - motor control of speech. - individual’s affect, judgment, personality, and inhibitions  Parts of the Brain CERREBRUM PARIETAL LOBE - sensory lobe - primary sensory cortex ' - individual’s awareness of the body in space, - orientation in space and spatial relations  Parts of the Brain CERREBRUM TEMPORAL LOBE - contains auditory receptive areas - interpretative area ' - provides integration of somatization, visual areas OCCIPITAL LOBE - for visual interpretation  Parts of the Brain CERREBRUM CORPUS CALLOSUM - connects the two hemispheres of brain - for transmission of information from one side of the brain to the other - (sensation, memory, learned discrimination) BASAL GANGLIA - masses of nuclei - control of fine motor movements (extremities)  Parts of the Brain CERREBRUM THALAMUS -relay station of all sensation except smell - memory, sensation, pain impulses pass through here HYPOTHALAMUS - has crucial role in endocrine system - regulates pituitary secretion - works with PG to maintain fluid balance, and temperature regulation - hunger center; sleep-wake cycle; BP; aggressive and sexual behaviors; emotional responses - control and regulate autonomimc nervous system  Parts of the Brain CERREBRUM PITUITARY GLAND - common site for brain tumors - frequently they are detected by physical signs and symptoms that can be traced to the pituitary, such as hormonal imbalance or visual disturbances secondary to pressure on the optic chiasm  Parts of the Brain CERREBRUM Topography of the cortex as it relates to function  Parts of the Brain BRAINSTEM MIDBRAIN - connects the pons and the cerebellum with the cerebral hemispheres; - contains sensory and motor pathways - center for auditory and visual reflexes. - CN III and IV origin  Parts of the Brain BRAINSTEM PONS - Cranial nerves V through VIII connect to the brain - contains motor and sensory pathways. - control the heart, respiration, and blood pressure.  Parts of the Brain BRAINSTEM MEDULLA OBLONGATA - contains motor fibers from the brain to the spinal cord; - sensory fibers from the spinal cord t the brain. - fibers cross, or decussate, at this level - CN IX through XII connect to the brain in the medulla.  Parts of the Brain CERREBELUM separated from the cerebral hemispheres by a fold of dura mater, the tentorium cerebelli. has both excitatory and inhibitory actions for coordination of movement. controls fine movement, balance, position sense , and integration of sensory input.  STRUCTURES PROTECTING THE BRAIN MENINGES - provide protection , support, and nourishment to the brain and spinal cord. Dura matter Arachnoid Pia matter  STRUCTURES PROTECTING THE BRAIN DURA MATTER outermost layer; covers the brain and the spinal cord tough, thick, inelastic, fibrous, and gray.  STRUCTURES PROTECTING THE BRAIN ARACHNOID middle membrane; an extremely thin appears white because it has no blood supply. contains the choroid plexus has arachnoid villi, that absorb CSF  STRUCTURES PROTECTING THE BRAIN PIA MATTER innermost membrane; a thin, transparent hugs the brain closely and extends into every fold of the brain’s surface. STRUCTURES PROTECTING THE BRAIN CEREBROSPINAL FLUID a clear and colorless fluid with a specific gravity of 1.007 produced in the ventricles and circulated around the brain and the spinal cord through the ventricular system. The two lateral ventricles -> third ventricle (foramen of Monro) --- fourth ventricle via the aqueduct of Sylvius. Fourth ventricle -> subarachnoid space and down the spinal cord on the dorsal surface. Arachnoid villi - absorb CSF Choroid plexus - CSF is produced composition is similar to other extracellular fluids (such as blood plasma) Normally with minimal number of WBC with no RBC.  CEREBRAL CIRCULATION ARTERIES Two internal carotid arteries and two vertebral arteries and their extensive system of branches provide blood supply to the brain. Internal carotid arteries - supply to the anterior of brain Basilar artery - joined vertebral arteries Vertebrobasilar arteries - supply most posterior of brain circulation Circle of Willis - provide collateral circulation if one or more of the four vessels supplying it becomes occluded or ligated.  CEREBRAL CIRCULATION ARTERIES  CEREBRAL CIRCULATION VEINS The network of the sinuses carries venous outflow from the brain and empties into the internal jugular vein, returning the blood to the heart. Do not have valves to prevent blood from flowing backward and depend on both gravity and blood pressure BLOOD BRAIN BARRIER a barrier to macromolecules and many compounds entering the brain All substances entering the CSF must filter through the capillary endothelial cells and astrocytes Blood–brain barrier has implications in the treatment and selection of medication for CNS disorders as well as serving a protective function. ANATOMY OF THE SPINAL CORD  SPINAL CORD Serve as the connection between the brain and the periphery Consists of gray (center) and white matter (surrounding) Surrounded by the meninges, dura, arachnoid, and pia layers An H-shaped structure with nerve cell bodies (gray matter) surrounded by ascending and descending tracts (white matter)  SENSORY & The Spianl Tracts MOTOR PATHWAYS white matter of the cord is composed of myelinated and unmyelinated nerve fibers. The fast-conducting myelinated fibers form bundles that also contain glial cells. Fiber bundles with a common function are called tracts. Six ascending tracts; eight descending tracts  SENSORY & The Spianl Tracts MOTOR PATHWAYS SIX ASCENDING TRACTS: 2 tracts for sensation (touch, pressure, vibration, position, passive motion) 2 spinocerebellar tracts for sensory impulses from muscle spindles (input for coordinated muscle contraction) 2 spinothalamic tracts for pain, temperature, proprioception, fine touch, vibratory sense from upper body to the brain.  SENSORY & The Spianl Tracts MOTOR PATHWAYS EIGHT DESCENDING TRACTS: 2 corticospinal tracts - motor impulses for voluntary muscle activities 3 vestibulospinal tracts - autonomic functions (sweating, pupil dilation, and circulation); and involuntary muscle control 1 corticobulbar tract - voluntary head and facial muscle movement 1 rubrospinal and 1 retculospinal tract - involuntary muscle movement  VERTEBRAL COLUMN surround and protect the spinal cord 7 cervical; 12 thoracic, and 5 lumbar vertebrae; sacrum (a fused mass of five vertebrae); coccyx. Nerve roots exit from the vertebral column through the intervertebral foramina (openings). The vertebrae are separated by disks, except for the first and second cervical, the sacral, and the coccygeal vertebrae. The Peripheral Nervous System The Peripheral Nervous System All nerves that branch out from CNS components and extend to other parts of the body The Peripheral Nervous System Cranial Nerves Spinal Nerves Autonomic and Somatic Nervous System Cranial Nerves SPINAL NERVES Also known as Volunatary SOMATIC Nervous System Control the voluntary muscle NERVOUS movements of the body Responsibile for reflex arc SYSTEM  Autonomic Nervous System Regulates the activities of internal organs Maintenance and restoration of internal homeostasis. Sympathetic Nervous System 1 “fight-or-flight” response 2 sympathetic neurotransmitter is norepinephrine (noradrenaline) Sympathetic neurons are located in the thoracic and the lumbar segments of 3 the spinal cord Parasympathetic Nervous System 1 ”Rest-or-digest” 2 Craniosacral division 3 parasympathetic nerves arise from the midbrain and the medulla oblongata. Motor System Functions Motor System Function Motor cortex controls the voluntary movements of body Consist of two-neuron pathway Motor System Function Upper and Lower Motor Neurons Upper and Lower Motor Motor System Function Neurons Upper Neuron Lower Nueron Located either in the anterior horn Originated in the of the spinal cord cerebral cortex, gray matter or cerebellum and within Cranial brain stem nerve nuclei in the brain stem. Upper and Lower Motor System Function Motor Neurons Motor System Function Coordination of Movement  Motor System Function Coordination of Movement The cerebellum is responsible for the coordination, balance and the timing of all muscular movements that originate in the motor centers of the cerebral cortex  Coordination of Movement Impaired cerebella function The patient may demonstrate decorticate, decebrate, or flaccid posture  Coordination of Movement Impaired cerebella function Coordination of Movement The basal ganglia play an important role in planning and coordinating motor movements and posture  Coordination of Movement Dysfunction of the basal ganglia Leads to muscle rigidity, with disturbances of the posture and movement.  Coordination of Movement Dysfunction of the basal ganglia Disorders due to lesions of the basal ganglia include Parkinson’s disease, Huntington’s disease and spasmodic torticollis Sensory System Function  Sensory System Funtion Integrating Sensory Impulses Conscious awareness of pain Integrates all Recognition of variation in the sensory temperature and touch. Sense of movement and impulse position. except Ability to recognize the size, olfactory shape, and quality of objects  Sensory System Funtion Receiving Sensory Impulses  Sensory System Funtion Sensory Losses Selective destruction or degeneration of the posterior columns of the spinal cord A lesion, such as a cyst, in the center of the spinal cord Lesions affecting the posterior spinal nerve roots Assessment: Neurological Examination  Health History The onset, character, severity, location, duration, and frequency of symptoms and signs. Family history of genetic disease Medical history System-by-system evaluation Clinical Manifestations Pain Seizures Dizziness Visual Disturbances Weakness Abnormal Sensation  Physical Examination Assessing Cerebral Function Mental Status Motor Ability Intellectual Function Language Ability Thought Content Impact on Lifestyle Emotional Status Documentation of Perception Findings Examining the Cranial Nerves Examining the Motor System muscle size tone strength coordination balance. Examining the Motor System Examining the Motor System Examining the Reflexes Testing these reflexes enables the examiner to assess involuntary reflex arcs that depend on the presence of afferent stretch receptors, spinal synapses, efferent motor fibers, and a variety of modifying influences from higher levels. Examining the Reflexes 0 No response 1+Diminished (hypoactive) 2+ Normal 3+ Increased (may be interpreted as normal) 4+Hyperactive (hyperreflexia) Examining the Reflexes Biceps reflex Patellar reflex Triceps reflex Ankle reflex Brachioradialis reflex Clonus Babinski reflex Superficial reflex Examining the Reflexes Sensory Examination Pain Light touch Temperature Position sense Vibration Discrimination sense Gerontological Considerations Structural Changes Motor Alterations Sensory Alterations Temperature Regulation and Pain Perception Taste and Smell Alterations Tactile and Visual Alterations Mental Status  DIAGNOSTIC EVALUATIONS DIAGNOSTIC EXAMS COMPUTED TOMOGRAPHY SCANNING Computed tomography (CT) makes use of a narrow x-ray beam to scan the head in successive layers. The images provide crosssectional views of the brain, with distinguishing differences in tissue densities of the skull, cortex, subcortical structures, and ventricles DIAGNOSTIC EXAMS POSITRON EMISSION TOMOGRAPHY Positron emission tomography (PET) is a computer-based nuclear imaging technique that produces images of actual organ functioning. The patient either inhales a radioactive gas or is injected with a radioactive substance that emits positively charged particles. DIAGNOSTIC EXAMS SINGLE PHOTON EMISSION COMPUTEDTOMOGRAPHY A three-dimensional imaging technique that uses radionuclides and instruments to detect single photons. It is a perfusion study that captures a moment of cerebral blood flow at the time of injection of a radionuclide DIAGNOSTIC EXAMS MAGNETIC RESONANCE IMAGING It has the potential for identifying a cerebral abnormality earlier and more clearly than other diagnostic tests. It can provide information about the chemical changes within cells, allowing the clinician to monitor a tumor’s response to treatment. DIAGNOSTIC EXAMS CEREBRAL ANGIOGRAPHY An x-ray study of the cerebral circulation with a contrast agent injected into a selected artery. Cerebral angiography is a valuable tool to investigate vascular disease, aneurysms, and arteriovenous malformations. I DIAGNOSTIC EXAMS NONINVASIVE CAROTID FLOW STUDIES Use ultrasound imagery and Doppler measurements of arterial blood flow to evaluate carotid and deep orbital circulation. The graph produced indicates blood velocity DIAGNOSTIC EXAMS MYELOGRAPHY An x-ray of the spinal subarachnoid space taken after the injection of a contrast agent into the spinal subarachnoid space through a lumbar puncture. DIAGNOSTIC EXAMS TRANSCRANIAL DOPPLER Uses the same noninvasive techniques as carotid flow studies except that it records the blood flow velocities. DIAGNOSTIC EXAMS ELECTROENCEPHALOGRAPHY It represents a record of the electrical activity generated in the brain. It is a useful test for diagnosing and evaluating seizure disorders, coma, or organic brain syndrome. DIAGNOSTIC EXAMS ELECTROMYOGRAPHY Obtained by introducing needle electrodes into the skeletal muscles to measure changes in the electrical potential of the muscles and the nerves leading to them  DIAGNOSTIC EXAMS NERVE CONDUCTION STUDIES Nerve conduction studies are performed by stimulating a peripheral nerve at several points along its course and recording the muscle action potential or the sensory action potential that results DIAGNOSTIC EXAMS LUMBAR PUNCTURE AND EXAMINATION OF CSF Queckenstedt's Test Cerebrospinal Fluid Analysis  ACUTE NEUROLOGIC CONDITIONS CEREBROVASCULAR ACCIDENT (CVA)  “Cerebrovascular disease” refers to any pathologic process involving blood vessels of the brain Cerebrovascular accident (CVA) is the medical term for a stroke.  Cerebrovascular Disease 1 Most common neurologic disorder in adults 2 Encompasses two major types of disorders, namely: Ischemic (85%) Hemorrhagic (15%)