Disorders of the Central and Peripheral Nervous Systems and Neuromuscular Junction

Traumatic Brain Injury (TBI)

Alteration in brain function from external force:

-motor vehicle accidents

-falls (most common in infants & elderly)

-unintentional blunt trauma

Primary:

-direct impact

-focal (closed or open) or diffuse

Secondary:

-indirect consequence of primary injury

-systemic and brain tissue responses

Glasgow Coma Scale

Domain: eye opening, best verbal, best motor

Response: spontaneous, to speech, to pain, none

oriented confused, inappropriate, incomprehensible, none

obeying, localizing, withdrawal, flexing, extending, none

Total Score: deep coma or death = 3

fully alert and oriented = 15

HIGHER SCORE THE BETTER

Categories of TBI

mild TBI (Mild Concussion): no/short loss of consciousness, GCS 13-15, confusion for several minutes, retrograde amnesia

moderate TBI (moderate concussion):

-loss of consciousness 30 minutes - 6 hours; GCS 9-12

-confusion with amnesia longer than 24 hours

-no signs of posturing or brain herniation

severe TBI (severe concussion):

-loss of consciousness longer than 6 hours; (GCS 3-8)

severe cognitive system defects & signs of brain stem damage

Complications of TBI

post-concussion syndrome:

-lasts for weeks or months post mild concussion

-HA, fatigue, dizziness, anxiety, difficulty with concentration

-symptomatic relief with observation

post traumatic seizures:

-occur within days, last up to 2-5 days post injury

-seizure prevention initiated early with moderate to severe TBI

Complications of TBI (2)

Chronic Traumatic Encephalopathy

Progressive dementing disease from repeated injury

-sports injury

-blast trauma

-work-related head trauma

—Violent behaviors, loss of control, depression, memory loss, change in cognition and motor function

Hematomas

*collection of blood outside the blood vessel*

Epidural: between dura mater and skull

Subdural: between dura mater and arachnoid membrane

Intracerebral: bleeding within the brain

Spinal Cord

Cervical Vertebrae: C1-C7

Thoracic Vertebrae: T1-T12

Lumbar Vertebrae: L1-L5

Sacrum: S1-S5

Spinal Cord (2)

lies within the vertebral canal, protected by the vertebral column

fxns: connect brain and body, conducts somatic and autonomic reflexes, provides motor pattern control centers, modulates sensory and motor function

end called the conus medullaris: nerves continue to form a nerve bundle called the cauda equina

Intervertebral Discs

-between each vertebral column

-contains nucleus pulposus at center- a pulpy mass of elastic fibers

-serves to absorb shock

-if excess stress, can rupture and cause compression of nerve root

Spinal Cord Injury

Primary: occurs with initial mechanical trauma and immediate tissue destruction

-occurs with inadequate mobilization following injury and may occur in absence of vertebral fracture or dislocation

Secondary: pathophysiologic cascade of events that begins immediately after injury and continues for weeks

-hemorrhages, inflammation, edema, ischemia

-life threatening is swelling in cervical region occurs: bc cardiovascular and respiratory control can be lost

Vertebral Injuries

-result from acceleration deceleration, or deformation forces

classification: simple fracture- single break

-compressed (wedged) fracture - vertebrae compressed anteriorly

-comminuted (burst) fracture- shattered into fragments

-dislocation

images on slide 14

Manifestations of Spinal Cord Trauma: Spinal Shock

Spinal Shock

-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, flaccid paralysis, absence of sensation, loss of bladder/rectal control, inability to regulate temperature, transient drop in blood pressure, bradycardia, poor venous circulation

-terminates with reappearance of reflex activity, hyperreflexia, spasticity, and reflex bladder emptying

Manifestations of Spinal Cord Trauma: Neurogenic Shock

-occurs with injury about T6

-caused by absence of sympathetic activity and unopposed parasympathetic tone

Manifestations of Spinal Cord Trauma: Autonomic Hyperreflexia (dysreflexia)

-sudden, massive reflex sympathetic discharge because descending inhibition is blocked

-stimulation of the sensory receptors below the level of the cord lesion

-image on slide 18

Cerebrovascular Disease (CVD)

-abnormality of the brain caused by a process in the blood vessels

-most frequent occurring neurologic disorder

-brain abnormalities:

ischemia with or without infarction, hemorrhage

Blood vessel abnormalities:

-lesions, occlusions, or rupture of vessel, alteration in blood quality

Cerebrovascular Accidents (Stroke Syndromes)

1) Leading cause of disability

2) third (females) and fifth (males) leading cause of death in United States

3) 25% of stroke are recurrent

4) Classified

-ischemic (thrombotic, embolic)

-hemorrhagic

-undetermined/cryptogenic

Ischemic strokes

1. Transient ischemic attacks (TIAs) : Ischemic event causing neurological dysfunction <1 hour, 12% of those having TIA will experience stroke

   2. Thrombotic stroke: obstruction by thrombus in arteries supplying the brain

   3. Embolic stroke: thrombus fragments obstructing small brain vessels

   4. Lacunar Strokes: occlusion of single, deep perforating artery of brain

   5. Hypoperfusion: systemic hypoperfusion decreases blood supply to brain

Cerebral Infarction

-when the area of the brain loses blood supply due to vascular occlusion

-central core of irreversible ischemia and necrosis, surrounded by rim of borderline hypoxic tissue (penumbra): prompt infusion of thrombolytic agents (tPA) may restore perfusion in punumbra and prevent necrosis

Ischemic— area pales and soften, necrosis

Ischemic Stroke

TIME IS TISSUE- intervene ASAP

imaging used to diagnose & locate

GOAL of IS: restore perfusion in timeframe that doesn’t cause reperfusion injury…

-want to administer Tissue Type Plasminogen Activator (tPA) w /in 3-4.5 hours

-surgically: thrombectomy or stent placement

Following Immediate Stabilization:

-prevent recurrence: antiplatelet therapy (typically aspirin), BP management

-rehabilitation: PT, OT, SLP

Prevent complication: What do you think potential complications might be? …

Hemorrhagic Stroke

bleeding occurs in brain tissue or subarachnoid/subdural spaces

HTN primary cause

mass of blood = compressed brain tissue, leading to ischemia, edema, and increased ICP + necrosis

symptoms may present similarly to ischemic stroke (may appear suddenly excruciating HA (worst of life), unresponsiveness, n/v

Goals: reduce bleeding, control BP/ICP, prevent rebleeding

Intracranial Aneurysm

Dilation/ballooning of cerebral vessel from weakness in vessel wall

classified by shape:

Saccular (berry) aneurysms

Fusiform (giant) aneurysms

Subarachnoid Hemorrhage

-blood escapes from defective or injured vasculature into the subarachnoid space

Risk: aneurysm, HTN, head injury, +FH, and arteriovenous malformation

Clinical Manifestations:

-H/A, AMS, n/v, altered vision or motor function

-Kernig/Brudzinski sign - d/t meningeal irritation

Often reoccur within 72 hrs: monitor for increased ICP, HTN, and deteriorating neurostatus

Primary Headache Syndromes : Migraine

Migraine:

-Episodic disorder characterized by HA lasts 4-72 hours

-usually, women 25 to 55 year old

-caused by combination of multiple genetic environmental factors

-chronic migraines occur > 14 days per month

Diagnosis: unilateral throbbing, worsened by movement, moderate/severe and on of: nausea, and/or vomiting, photophobia, and phonophobia

Primary Headache: Cluster Headache

-involves autonomic division of trigeminal nerve

-occur in clusters (min to hrs) for a period of days followed by a long period of remission

-usually, men between 20 to 50 years old

-unilateral severe pain with manifestations on the same side of the body (tearing and ptosis of the eye, stuffy nose)

Primary Headache: Tension-type Headache

Tension-type Headache

-most common recurrent headache

-average onset 2nd decade

-mild to moderate bilateral headache with sensation of a tight band or pressure around the head with gradual onset of pain

-occurs in episodes and may last for several hours or several days

-chronic version occurs at least 15 days per month for at least 3 months

Meningitis

-inflammation of brain or spinal cord

-infectious meningitis caused by: bacteria, viruses, fungi, parasites, toxins

-may be acute, subacute, or chronic

Meningitis (Bacterial)

Bacterial:

-infection of pia mater, arachnoid villi, subarachnoid space, ventricular system, and CSF

-caused by meningococci and pneumococci crossing the BBB and infect meninges

-causes infections, meningeal, and neurologic signs

-acute infectious purpura fulminans (rare, but deadly hematologic complication - 43% mortality : characterized by hemorrhagic necrosis and DIC

-rapid diagnosis and treatment essential to prevent morbidity and mortality

Meningitis (Viral)

Viral

-Infection limited to the meninges

-caused by enteroviral viruses, arboviruses, and herpes simplex 2

crosses the BBB

-clinical manifestations are milder than bacterial

Encephalitis

acute inflammation of the brain, usually from viral

caused by:

-bites of mosquitos, ticks, flies

-herpes simplex type 1

-may occur as complication of systemic viral disease

ranges from mild infectious disease to life-threatening disorder

Brain or Spinal Cord Abscess

Localized collection of pus within parenchyma

Immunosuppressed people at particular risk

Brain abscesses: extradural, subdural, intracerebral

Spinal Cord Abscesses: epidural, intramedullary

Clinical Manifestations of Brain/Spinal Cord Abscess

HA is most common early symptom

Later associated w/ expanding mass

Brain abscess: localized pain, purulent drainage from nose or ears, fever, localized tenderness, neck stiffness

Spinal cord abscess: spinal aching, severe root pain with back muscle spasms and limited vertebral movement, weakness, paralysis

Neurologic Complications of AIDS

Human immunodeficiency virus—associated neurocognitive disorder (HAND): Mild neurocognitive disorder, HIV- assosciated dementia, combined antiretroviral therapy has reduced prevalence and improved survival

Demyelinating Disorders

Disorders of the Periphery

Multiple Sclerosis

-chronic progressive immune mediated inflammatory disease

-multiple focal areas of myelin loss (plaques): disrupts nerve conduction with subsequent death of neurons and brain atrophy

four subtypes based on clinical course

REVIEW 17.9

Guillain-Barre Syndrome

Acquired inflammatory disease-causing demyelination of the peripheral nerves

-tingles, weakness, paralysis of the legs, quadriplegia, respiratory insufficiency, autonomic nervous system instability

-may require mechanical ventilation

-usually follows respiratory tract or GI infection

-recovery in weeks to months: -30% with residual weakness

Neuromuscular Disorder: Myasthenia Gravis

-Acquired chronic autoimmune disease; defect in nerve impulse transmission at neuromuscular junction, an IgG antibody is produced against acetylcholine receptors and post-synaptic neuro muscular jxn (Acetylcholine)

-weakness/fatigue eye muscles + throat —> diplopia + difficulty chewing talking swallowing = concern for ventilation and aspiration

diagnosed: by EMG, antibody presence, Tensilon test: improvement in muscle strength with administration of Acetylcholinesterase inhibitor

Myasthenic Crisis

-due to disease progression

-severe weakness leading to quadriparesis respiratory insufficiency and trouble swallowing

Cholinergic Crisis

-anticholinesterase drug toxicity

-increased intestinal peristalsis, diarrhea, bradycardia, drooling, sweating

CNS Tumors : Brain

Brain tumors: effects are due to compression or reduced blood flow

CNS tumors: primary brain (glioma)

originate in brain; do. notmetastasize as easily due to no lymphatic channels in area

examples: astrocytoma, oligodendroglioma, ependymoma

-glioblastoma multiforme- most lethal d/t high vascularity and infiltration

CNS tumor: extracerebral tumors

outside brain

-meningioma & nerve sheath tumors (neurofibromatosis)

CNS tumor: metastatic brain tumors

most prevalent; likely from lung, skin, breast

Central Nervous System Tumors

Spinal cord tumors)

1) intramedullary tumors (within neural tissues)

2) extramedullary tumors (tissues outside spinal cord)

-manifestations due to invasion & compression:

-Compressive syndrome: pain and affected motor/sensory function

-irritative syndrome: cord compression & radicular pain