Alterations of Neurologic Function Chapter 17 1 Brain

Alterations of Neurologic Function Chapter 17 1

Brain Trauma o Traumatic brain injury n n A traumatic insult to the brain possibly producing physical, intellectual, emotional, social, and vocational changes 50% are motor vehicle accidents 21% are falls Others: violence and sports 2 Mosby items and derived items © 2006 by Mosby, Inc.

Brain Trauma o Blunt (closed, nonmissile) trauma n n n o Head strikes hard surface or a rapidly moving object strikes the head The dura remains intact and brain tissues are not exposed to the environment Causes focal (local) or diffuse (general) brain injuries Open (penetrating, missile) trauma n n Injury breaks the dura and exposes the cranial contents to the environment Causes primarily focal injuries 3 Mosby items and derived items © 2006 by Mosby, Inc.

Brain Trauma o Coup injury n o Contrecoup n o o Injury directly below the point of impact Injury on the pole opposite the site of impact Compound fractures Basilar skull fracture 4 Mosby items and derived items © 2006 by Mosby, Inc.

Brain Trauma 5 Mosby items and derived items © 2006 by Mosby, Inc.

Focal Brain Injury o o o Observable brain lesion Force of impact typically produces contusions Contusions can cause: n n n Extradural (epidural) hemorrhages or hematomas Subdural hematomas Intracerebral hematomas 6 Mosby items and derived items © 2006 by Mosby, Inc.

Extradural (Epidural) Hematomas 7 Mosby items and derived items © 2006 by Mosby, Inc.

Subdural (Epidural) Hematomas 8 Mosby items and derived items © 2006 by Mosby, Inc.

Diffuse Brain Injury o Diffuse axonal injury (DAI) n n n Shaking, inertial effect Acceleration/deceleration Axonal damage o n Shearing, tearing, or stretching of nerve fibers Severity corresponds to the amount of shearing force applied to the brain and brain stem 9 Mosby items and derived items © 2006 by Mosby, Inc.

Diffuse Brain Injury (DAI) o Categories: n n n Mild concussion Classical concussion Mild, moderate, and severe diffuse axonal injuries (DAI) 10 Mosby items and derived items © 2006 by Mosby, Inc.

Mild Concussion o Temporary axonal disturbances causing attention and memory deficits but no loss of consciousness n n n I—confusion, disorientation, and momentary amnesia II—momentary confusion and retrograde amnesia III—confusion with retrograde and anterograde amnesia 11 Mosby items and derived items © 2006 by Mosby, Inc.

Classic Cerebral Concussion o Grade IV n n Disconnection of cerebral systems from the brain stem and reticular activating system Physiologic and neurologic dysfunction without substantial anatomic disruption Loss of consciousness (<6 hours) Anterograde and retrograde amnesia 12 Mosby items and derived items © 2006 by Mosby, Inc.

Diffuse Axonal Injury o Produces a traumatic coma lasting more than 6 hours because of axonal disruption n Mild Moderate Severe 13 Mosby items and derived items © 2006 by Mosby, Inc.

Spinal Cord Trauma o Most commonly occurs due to vertebral injuries n o o Simple fracture, compressed fracture, and comminuted fracture Traumatic injury of vertebral and neural tissues due to compressing, pulling, or shearing forces Most common locations: cervical (1, 2, 4 -7), and T 1– L 2 lumbar vertebrae n Locations reflect most mobile portions of vertebral column and the locations where the spinal cord occupies most of the vertebral canal 14 Mosby items and derived items © 2006 by Mosby, Inc.

Spinal Cord Trauma 15 Mosby items and derived items © 2006 by Mosby, Inc.

Spinal Cord Trauma 16 Mosby items and derived items © 2006 by Mosby, Inc.

Spinal Cord Trauma o Spinal shock n n Normal activity of the spinal cord ceases at and below the level of injury. Sites lack continuous nervous discharges from the brain. Complete loss of reflex function (skeletal, bladder, bowel, sexual function, thermal control, and autonomic control) 17 Mosby items and derived items © 2006 by Mosby, Inc.

Spinal Cord Trauma 18 Mosby items and derived items © 2006 by Mosby, Inc.

Spinal Cord Trauma o o o Paraplegia Quadriplegia Autonomic hyperreflexia (dysreflexia) n n Massive, uncompensated cardiovascular response to stimulation of the sympathetic nervous system Stimulation of the sensory receptors below the level of the cord lesion 19 Mosby items and derived items © 2006 by Mosby, Inc.

Autonomic Hyperreflexia 20 Mosby items and derived items © 2006 by Mosby, Inc.

Degenerative Disorders of the Spine o Degenerative disk disease (DDD) n n n o o Spondylolysis Spondylolisthesis Spinal stenosis Low back pain Herniated intervertebral disk 21 Mosby items and derived items © 2006 by Mosby, Inc.

Cerebrovascular Disorders o Cerebrovascular accidents (CVAs) n Thrombotic stroke o o n Arterial occlusions caused by thrombi formed in arteries supplying the brain or in the intracranial vessels Transient ischemic attacks Embolic stroke o Fragments that break from a thrombus formed outside the brain 22 Mosby items and derived items © 2006 by Mosby, Inc.

Cerebrovascular Disorders o o Hemorrhagic stroke Lacunar stroke Cerebral infarction Cerebral hemorrhage 23 Mosby items and derived items © 2006 by Mosby, Inc.

Cerebrovascular Disorders o Intracranial aneurysm n n Saccular (berry) aneurysms Fusiform (giant) aneurysms Mycotic aneurysms Traumatic aneurysms 24 Mosby items and derived items © 2006 by Mosby, Inc.

Intracranial Aneurysm 25 Mosby items and derived items © 2006 by Mosby, Inc.

Cerebrovascular Disorders o Vascular malformations n n Cavernous angiomas Capillary telangiectasis Venous angioma Arteriovenous malformation 26 Mosby items and derived items © 2006 by Mosby, Inc.

Cerebrovascular Disorders o Subarachnoid hemorrhage n o Blood escapes from defective or injured vasculature into the subarachnoid space Manifestations n n Kernig sign Brudzinski sign 27 Mosby items and derived items © 2006 by Mosby, Inc.

Headache o Migraine headache n n o Trigger factors Aura Cluster headache n Several attacks can occur during the day for a periods of days followed by a long period of spontaneous remission 28 Mosby items and derived items © 2006 by Mosby, Inc.

Headache o Chronic paroxysmal hemicrania n o Cluster-type headache that occurs with more daily frequency but with shorter duration Tension-type headache n Mild to moderate bilateral headache with a sensation of a tight band or pressure around the head 29 Mosby items and derived items © 2006 by Mosby, Inc.

Central Nervous System Tumors o Cranial tumors n Primary intracerebral tumors (gliomas) o o o n Astrocytoma Oligodendroglioma Ependymoma Primary extracerebral tumors o o o Meningioma Nerve sheath tumors Metastatic carcinoma 30 Mosby items and derived items © 2006 by Mosby, Inc.

Central Nervous System Tumors o Spinal cord tumors n n Intramedullary tumors Extramedullary tumors o o n Intradural Extradural Manifestations o o o Compressive syndrome Irritative syndrome Syringomyelic syndrome 31 Mosby items and derived items © 2006 by Mosby, Inc.

Spinal Cord Tumors 32 Mosby items and derived items © 2006 by Mosby, Inc.

Infection and Inflammation of the CNS o Meningitis n n Bacterial meningitis Aseptic (viral, nonpurulent, lymphocytic) meningitis Fungal meningitis Tubercular (TB) meningitis 33 Mosby items and derived items © 2006 by Mosby, Inc.

Meningitis 34 Mosby items and derived items © 2006 by Mosby, Inc.

Infection and Inflammation of the CNS o Suppurative cerebral masses n n Cerebral abscess Spinal cord abscess o Intramedullary spinal cord abscess 35 Mosby items and derived items © 2006 by Mosby, Inc.

Infection and Inflammation of the CNS o Encephalitis n n Acute febrile illness, usually of viral origin with nervous system involvement Most common forms of encephalitis are caused by arthropod-borne viruses and herpes simplex virus 36 Mosby items and derived items © 2006 by Mosby, Inc.

Neurologic Complications of AIDS o o o o Human immunodeficiency-associated cognitive dysfunction HIV myelopathy HIV neuropathy Aseptic viral meningitis Opportunistic infections Cytomegalovirus infections Parasitic infection CNS neoplasms 37 Mosby items and derived items © 2006 by Mosby, Inc.

Lyme Disease o o o Tick-borne spirochete bacterial infection Borrelia burgdorferi Progression n o Introduced by tick bite Incubates 3 to 32 days Migrates to skin, lymph nodes, and other body systems Stages 38 Mosby items and derived items © 2006 by Mosby, Inc.

Demyelinating Disorders o Multiple sclerosis (MS) n n MS is a progressive, inflammatory, demyelinating disorder of the CNS Types: o o o Mixed (general) Spinal Cerebellar 39 Mosby items and derived items © 2006 by Mosby, Inc.

Peripheral Nervous System Disorders o Neuropathies n Generalized symmetric polyneuropathies o o n Generalized neuropathies o n Distal axonal polyneuropathy Demyelinating polyneuropathy Sensory neuropathies Focal or multifocal neuropathies 40 Mosby items and derived items © 2006 by Mosby, Inc.

Peripheral Nervous System Disorders o Guillain-Barré syndrome n n n Acquired inflammatory disease causing demyelination of the peripheral nerves with relative sparing of axons Acute onset, ascending motor paralysis Humoral and cellular immunologic reaction 41 Mosby items and derived items © 2006 by Mosby, Inc.

Peripheral Nervous System Disorders o Amyotrophic lateral sclerosis (ALS) n n Classic ALS—“Lou Gehrig disease” Diffusely affects upper and lower motor neurons of the cerebral cortex, brain stem, and spinal cord (corticospinal tracts and anterior roots) Disease leads to progressive weakness leading to respiratory failure and death Patient has normal intellectual and sensory function until death 42 Mosby items and derived items © 2006 by Mosby, Inc.

Peripheral Nervous System Disorders o Radiculopathies n Radiculitis o n o Inflammation of the spinal nerve roots Radicular pain Plexus injures n Involves the nerve plexus distal to the spinal roots but proximal to the formation of the peripheral nerves 43 Mosby items and derived items © 2006 by Mosby, Inc.

Neuromuscular Junction Disorders o Myasthenia gravis n n n Chronic autoimmune disease An Ig. G antibody is produced against acetylcholine receptors (antiacetylcholine receptor antibodies) Weakness and fatigue of muscles of the eyes and the throat causing diplopia, difficulty chewing, talking, swallowing 44 Mosby items and derived items © 2006 by Mosby, Inc.

Neuromuscular Junction Disorders o Myasthenia gravis n Classification o o o n n Neonatal myasthenia Congenital myasthenia Juvenile myasthenia Ocular myasthenia Generalized autoimmune myasthenia Myasthenia crisis Cholinergic crisis 45 Mosby items and derived items © 2006 by Mosby, Inc.