Cns Ho2. Dysfunctions

NEURO HO2: CNS DYSFUNCTIONS I. Cerebrovascular Disorders Strokes: 2 major categories 1. ischemic (more common) 2. hemorrhagic (less common) A. Ischemic Stroke / Cerebrovascular Accident (CVA) / Brain Attack - with sudden loss of function resulting from disruption of blood supply to a part of the brain - 5 types of ischemic strokes (according to etiology): 1. small penetrating artery thrombosis - also called lacunar stroke because of the cavity that is created once the infarcted brain tissue disintegrates - most common type of ischemic stroke 2. large artery thrombosis - due to atherosclerotic plaques in the large vessels of the brain

3. cardiogenic embolic stroke - associated with cardiac dysrrhytmias, usually atrial fibrillation - left middle cerebral artery - most commonly affected 4. cryptogenic - no known cause 5. other - ex. related to cocaine use, coagulopathies,etc. Acute Stroke

® MCA infarct

coronal section of brain

57/M who developed left hemiparesis over the course of a few minutes; died after 3 days

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

1

31/F on oral contraceptives woke up unable to speak and move her right arm and leg; died of cardiac arrythmia 24 hrs. later coronal section revealed an acute infarct of the left MCA

_________________________________________________________________________________ Old Stroke

old ® MCA infarct (2 yrs. post-CVA)

cross section

73/M with past CVA, initially severely hemiplegic with partial recovery; died of pulmonary embolism

- pathophysiology: - the ischemic cascade begins when the cerebral blood flow falls to less than 25ml/100g/min.; at this point the neurons can no longer maintain aerobic respiration - the ensuing anaerobic respiration generates large amounts of lactic acid which changes the pH and renders the neurons incapable of producing sufficient ATPs; from here on the cells cease to function - around the infarcted area is an area of low cerebral blood flow (penumbra region) - THE STROKE CONTINUUM (Time Course Classification): > Transient Ischemic Attack (TIA) - temporary neurologic dysfunction; does not last longer than 24 hrs. - complete recovery is expected - serves as a warning of impending stroke (usually within the first month following the attack) > Reversible Ischemic Neurologic Deficits - S/Sx last longer than 24 hrs. - complete recovery is expected > Stroke in Evolution - worsening S/Sx; progressing stroke > Completed Stroke - stabilization of the neurologic s/sx; no further progression of hypoxic insult - S/Sx: * motor loss > most common dysfunction - hemiplegia (paralysis of one side of the body) due to a lesion of the opposite side of the brain > hemiparesis - weakness of one side of the body

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

2

* communication loss > dysarthria (difficulty in speaking) due to paralysis of muscles responsible for producing speech > dysphasia or aphasia (defective speech or loss of speech) expressive aphasia - damage in Broca’s area (frontal); with trouble producing grammatical language receptive aphasia - damage in Wernicke’s area (temporal); can hear spoken language but cannot understand it global aphasia - mixed > apraxia (inability to perform a previously learned action) * perceptual disturbances > visual-perceptual - disturbance in the sensory pathway between the eye and the visual cortex (occipital lobe) * homonymous hemianopsia (loss of half of the visual field on the same side in both eyes) - affected side of vision corresponds to the paralyzed side of the body

The visual images that we see on the right side travel from both eyes to the left side of the brain, while the visual images we see on the left side in each eye travels to the right side of the brain. Therefore, damage to the left side of the posterior (occipital lobe) portion of the brain can cause a loss of the right field of view in both eyes. Likewise, damage to the right posterior brain can cause a loss of the left field of vision.

* visual-spatial (perceiving the relation of 2 or more objects in space) * sensory loss - ranges from slight impairment of touch to loss of proprioception (perception of the position and motion of the body in space) * cognitive impairment and psychological effects Right-sided Stroke > paralyzed on the left side > impaired judgment > impaired time concepts > with spatial-perceptual deficits > rapid performance. short attention span > tends to deny or minimize problems > with left-side neglect

Left-sided Stroke > paralyzed on the right side > impaired speech, language / aphasia > impaired comprehension related to language and math > impaired right-left discrimination > slow performance, cautious > aware of his deficits, depressed, anxious

* diagnosis: initial test - CT scan * prevention: unmodifiable risk factors - age (more than 55 yrs.) - family history - gender (more common in males) - prior stroke, TIA, or heart attack

NCM 104 Lec - CNS Disorders

modifiable risk factors - cardiovascular disease - cigarette smoking - DM - physical inactivity / obesity

Gener C. Sibal, RN,MD,FPOA

3

* Medical Mx: * Warfarin (Coumadin) - used for long-term anticoagulation - only available in oral form - monitored by prothrombin time (PT) / (INR) * normal PT value: 9.6 - 11.8 secs. (adult male) > desired (therapeutic) effect: prolonged PT The traditional method of determining the efficacy of anticoagulation therapy is the prothrombin time (PT). This was first described by Armand J. Quick in 1935. He used thromboplastin derived from rabbit brains to prove his assumption that patients with bleeding abnormalities secondary to obstructive jaundice was due to a deficiency of prothrombin. This is now known to result from reduced levels of liver-produced vitamin K-dependent blood coagulation factors II, IX, and X. Today a blood sample is collected in a tube containing citrated sodium, in the laboratory the sample is spun in a centrifuge, and a specific volume of thromboplastin reagent is added to the sample. The time until a fibrin clot forms, measured in seconds, is reported as the PT. Because thromboplastins are produced using different methods and from different sources, the sensitivity of an individual thromboplastin to another can vary greatly. The more sensitive the thromboplastin reagent the longer the resulting PT. Conversely, the less sensitive the reagent the shorter the resulting PT. Variance can even occur within a single batch depending on shelf time. This variability in sensitivity and its effect on PT outcomes can have a major detrimental effects on the management of warfarin therapy in patients requiring anticoagulation. This variability has also caused great international debate and concern for several decades. To help standardize this difference two formats were developed, the first was the International Sensitivity Index (ISI) and the second was the International Normalized Ratio (INR). The INR was developed to incorporate the ISI values and attempt to make PT results uniformly useable.

warfarin tabs

* normal INR: 1.3 to 2 > treatment goal: INR value of 2 to 3

INR is not a separate lab test but a mathematical calculation that corrects for the variability in PT results attributable to the variable sensitivities (ISI- International Sensitivity Index)) of the thromboplastin agents used by laboratories

antidote

- antidote: phytonadione (AquaMEPHYTON) * thrombolytic therapy: - ex. streptokinase / urokinase / t-PA (tissue plasminogen activator) / alteplase - these drugs activate plasminogen which generates plasmin (that enzyme that dissolves clots) - most common side effect of these drugs: bleeding - antidote: aminocaproic acid

streptokinase

NCM 104 Lec - CNS Disorders

aminocaproic acid

Gener C. Sibal, RN,MD,FPOA

4

* antiplatelet medications: - ex. aspirin / dipyridamole / ticlopidine / abciximab - these drugs inhibit platelet aggregation, therefore = prolonged bleeding time

* Nursing Interventions: > improving mobility and preventing joint deformities / contractures - correct positioning: - to prevent shoulder adduction - pillow is placed in the axilla; elbow slightly flexed with the arm in neutral - hands / fingers - barely flexed; in slight supination - establish an exercise program; passive ROM to prevent contractures - prone position for 15 to 30 mins. 3x a day; pillow placed under pelvis extending to upper 3rd of thigh to hyperextend the hips and the knees * prone position also helps drain bronchial secretions - never pull on the arm when lifting patients > maintain skin integrity - position should be changed every 2 hours * position patient 2 hrs. on the unaffected side; 20 mins. on the affected side > elevate head of bed at least 30° to prevent aspiration * when eating - patient should be in sitting position - place food at the back of the mouth on the unaffected side > maintain BP at 150/100mmHg to maintain perfusion > suction secretions but never nasally and not longer than 10 secs. to prevent an increase in ICP > improve family coping > help patient cope with sexual dysfunction > teach self-care

B. Hemorrhagic Stroke / Bleed - less common than ischemic type but with more severe deficits and longer recovery time - 2 types: 1. primary - more common; due to spontaneous rupture of small vessels 2. secondary - associated with arteriovenous malformation (AVM); intracranial aneurysms; due to certain medications e.g. anticoagulants, amphetamines - pathophysiology: A. intracerebral hemorrhage - bleeding is caused by any factor which may cause rupture of the vessel which has been rendered weak by degenerative changes or by erosion of a vessel by a space-occupying lesion - common in hypertension and cerebral atherosclerosis

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

5

basal ganglia

cross-section

65/M who developed progressively severe headaches, accompanied by the sudden onset of left hemiparesis and hemianopsia; died 36 hrs. later from a pulmonary embolus

lobar hemorrhage

cross-section

57/M with severe thrombocytopenia and presented with a left homonymous hemianopsia and clouding of consciousness progressing over a few hours; died 36 hours later

B. intracranial aneurysms - bleeding is due to weakness of the arterial walls

diagram

angiogram

close-up

CT scan

C. AV malformation - abnormal embryonic development leads to a tangle of arteries and veins without a capillary bed; absence of capillary beds leads to dilatation of the arteries and veins and their eventual rupture

tangle of arteries and veins

NCM 104 Lec - CNS Disorders

bleeding into the brain substance

Gener C. Sibal, RN,MD,FPOA

6

D. subarachnoid hemorrhage - bleeding from any of the above which enters the SA space

normal

with bleed

actual specimen

* S/Sx: similar to those with ischemic type plus intense headache which may or may not be followed by LOC (for AVM) * Nursing Mx: > assist MD > supplemental oxygenation > same as those of ischemic *** Resolving Hematoma

CT scan taken

1 mo. after the event

3 mos. after the event

patient who had lobar hemorrhage but survived

II. Neurologic Trauma A. Scalp Injuries

scalp lacerations

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

7

s c a l p

2

a v u l s i o n

weeks

c o m p l e t e l y

post-op

r e c o v e r e d

> Nursing Intervention: - prepare necessary instruments - assist MD with suturing and repair - secure x-ray plates

B. Skull Fractures

post-mortem

CT scan

depressed fracture

> S/Sx:

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

8

Battle’s sign (mastoid ecchymosis)

racoon eyes (periorbital hematoma)

otorrhea (CSF coming from the ear)

halo sign (blood stain sorrounded by a yellowish stain on bed linens / dressings) > Nursing Mx: - if in doubt if otorrhea or rhinorrhea consist of CSF - test for glucose - do not insert NGT/perform nasotracheal suctioning if patient is suspected of having a basal skull fracture - for basal skull fractures: plug loosely (nose or ear) with sterile cotton and elevate head 30° to decrease ICP and promote spontaneous closure of leak (if nose); some prefer to have the patient lie on the side with the leaking side up (if ears) C. Brain Injury - may be closed (no opening through the skull) or open (with opening) 1. concussion - temporary loss of neurologic function with no apparent structural damage

2. contusion - the brain is bruised 3. intracranial hemorrhage a. epidural hematoma - blood collects between the skull and the dura mater - bleeding usually arterial in origin but may be venous

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

9

- usual clinical course: ↓ sensorium or (+) LOC followed by lucid interval (seeming recovery) the lapses back into unconsciousness usually after 1 to 2 hrs. b. subdural hematoma - bleeding is usually venous - bleeding is between the dura mater and the arachnoid mater

- usual clinical course: feels alright after the trauma then develops neuro s/sx over the next few days - classification: 1. acute - s/sx appear within 2 days 2. subacute - within 2 to 14 days 3. chronic - > 14 days Intracranial Pressure (ICP) > normal ICP - 10 to 20 mmHg * measured by “CPP” - cerebral perfusion pressure (pressure driving cerebral blood flow) → CPP = MAP (Mean Arterial Pressure) - ICP CPP ≥ 70 indicates adequate brain viability > most sensitive and earliest indication of increasing ICP - decreasing level of consciousness > hallmark sign of ↑ ICP: papilledema (swelling of the optic disk) * optic disk - “blind spot”; area where the optic nerve enters

normal optic disk

p a p i l l e d e m a

> Nursing Mx:

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

10

* with ↑ ICP: - elevate head of bed 30-40° - avoid Trendelenburg position - prevent flexion of neck and hips/knees - will result to decreased venous drainage from the brain - don’t give morphine sulfate - this will cause respiratory depression leading to hypoxia which in turn will result to further increase in ICP - when patient is connected to a mechanical ventilator: * maintain PaCO2 at 30-35mmHg - will constrict cerebral blood vessels → ↓ blood flow → ↓ ICP * maintain slight hyperventilation to prevent ↑ ICP - CO2 retention causes ↑ ICP; hyperventilation blows off CO2 - do not give hypertonic IV solutions - CONTROVERSIAL * will attract water and increase ICP * hypertonic solutions like mannitol does not cross the blood-brain barrier and draws fluid from the brain into the general circulation thus decreasing ICP - prevent shivering - shivering increases ICP * meds used to prevent shivering: chlorpromazine HCl (Thorazine) meperidine HCL (Demerol) - prevent hyperthermia: * hyperthermia → ↑ cerebral metabolism → ↑ hypoxia → ↑ ICP - positioning of the patient after surgery: * supratentorial - do not lower HOB * infratentorial / posterior fossa surgery - do not elevate HOB; patient lies on his side → intracranial space (inside of the skull): divided into 2 compartments 1. supratentorial compartment - area above the tentorium cerebelli 2. infratentorial compartment - area below the tentorium cerebelli - also called the posterior fossa

II. Cerebrospinal Fluid

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

11

> CSF is produced mainly by a structure called the choroid plexus in the right and left lateral, third and fourth ventricles > CSF flows from the 2 lateral ventricles to the third ventricle through the interventricular foramen (also called the foramen of Monro) > CSF flows from the third ventricle to the fourth ventricle through the cerebral aqueduct (also called the Aqueduct of Sylvius) > from the fourth ventricle CSF then flows into the cisterna magna through the lateral foraminae of Luschka (there are two of these) and the median foramen of Magendie (only one of these) * cisterna magna - opening in the subarachnoid space created by the separation of the arachnoid and pia mater > CSF flows down the dorsal surface of the spinal cord and is then returned to the brain where it is absorbed back into the blood stream through the arachnoid villi * when the CSF pressure is greater than the venous pressure, CSF will flow into the blood stream; however, if the CSF pressure is less than the venous pressure, the arachnoid villi will not let blood pass into the ventricular system * normal adult - approximately 500 ml of CSF is produced / day - approximately 125 to 150 ml is left unabsorbed and circulating at any given time CSF functions: 1. protection - CSF acts to cushion a blow to the head and lessen the impact 2. bouyancy - because the brain is immersed in fluid, the net weight of the brain is reduced from about 1,400 grams to about 50 grams; therefore, pressure at the base of the brain is reduced 3. excretion of waste products - the one-way flow from the CSF to the blood takes potentially harmful metabolites, drugs and other substances away from the brain 4. endocrine medium - CSF serves to transport hormones to other areas of the brain; hormones released into the CSF can be carried to remote sites of the brain where they may act III. Hydrocephalus - "water on the brain" - occurs when excess fluid builds up in the brain; the excess fluid can push fragile brain tissue up against the skull which may cause brain damage / death

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

12

- s/sx: vary by age group and disease progression in infants → an unusually large head a rapid increase in the size of the head a bulging "soft spot" on the top of the head sucking or feeding problems / vomiting sleepiness in older children and adults → headache followed by vomiting nausea blurred or double vision eyes fixed downward (sunsetting of the eyes) problems with balance, coordination or gait sluggishness or lack of energy

irritability / high-pitched cry seizures eyes fixed downward (sunsetting of the eyes) developmental delay

slowing or regression of development memory loss confusion urinary incontinence irritability changes in personality

- hydrocephalus presents in one of two forms: a. non-communicating hydrocephalus - caused by a blockage in the ventricular pathway through which the CSF flows b. communicating hydrocephalus - caused by the poor absorption of CSF; pathways are not obstructed - risk factors: a. infant prematurity - increased risk of bleeding b. intrapartum uterine infection c. congenital / developmental defects - diagnostic tools: a. routine pre/post-natal USG (before the bones of the skull harden and close) b. routine head circumference measurements c. ct scan d. mri * The severity of hydrocephalus depends on the age at which the condition develops and the course it follows. If the condition is well advanced at birth, major brain damage and physical disabilities are likely. In less severe cases, with proper treatment, it's possible to have a nearly normal life span and intelligence.

- treatment: NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

13

a. shunt - consists of a long flexible tube with a valve that keeps fluid from the brain flowing in the right direction and at the proper rate - one end of the tubing is usually placed in one of the brain's ventricles, the tubing is then tunneled under the skin to another part of the body where the excess cerebrospinal fluid can be more easily absorbed — such as the abdomen or a chamber in the heart (RA)

b. ventriculostomy - sometimes used when there's an obstruction of flow between ventricles - the surgeon makes a hole in the bottom of one of the ventricles to allow the cerebrospinal fluid to flow toward the base of the brain where normal absorption occurs - prevention: a. get regular prenatal care to reduce the risk of premature labor b. protect baby or child from head c. keep child immunizations up-to-date IV. Cerebral Palsy - "cerebral" → brain / "palsy" → muscle weakness / poor control - caused by damage to one or more specific areas of the brain, usually occurring during fetal development; before, during, or shortly after birth; or during infancy - not caused by problems in the muscles or nerves; instead, faulty development or damage to motor areas in the brain disrupt the brain's ability to adequately control movement and posture - not progressive (i.e. brain damage does not get worse); however, secondary conditions, such as muscle spasticity, can develop which may get better over time, get worse, or remain the same - not communicable; not "curable" but training and therapy can help improve function

- characterized by an inability to fully control motor function, particularly muscle control and coordination * depending on which areas of the brain have been damaged, one or more of the following may occur: 1. disturbance in gait or mobility a. muscle tightness or spasticity b. involuntary movement 2. abnormal sensation and perception a. impairment of sight, hearing or speech 3. seizures and/or mental retardation 4. difficulties in feeding / bladder and bowel control 5. problems with breathing because of postural difficulties

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

14

6. skin disorders because of pressure sores - types of cerebral palsy: a. spastic cerebral palsy (70 to 80%) - muscles are stiffly and permanently contracted - description is based on which limbs are affected, i.e spastic diplegia (both legs) or left hemi-paresis (the left side of the body) b. choreoathetoid or athetoid or dyskinetic cerebral palsy (10 to 20%) - characterized by uncontrolled, slow, writhing movements - these abnormal movements usually affect the hands, feet, arms, or legs and, in some cases, the muscles of the face and tongue, causing grimacing or drooling - the movements often increase during periods of emotional stress and disappear during sleep - may also have problems coordinating the muscle movements needed for speech (dysarthria) c. ataxic cerebral palsy (5 to 10%) - affects the sense of balance and depth perception - with poor coordination; walk unsteadily with a wide-based gait, placing their feet unusually far apart; and experience difficulty when attempting quick or precise movements, such as writing or buttoning a shirt - may also have intention tremor (begins as a voluntary movement which is transformed into trembling that affects the body part being used and that worsens as the individual gets nearer to the desired object d. mixed forms - most common mixed form → spasticity and athetoid movements - early signs of cerebral palsy: * usually appear before 3 yrs. of age (usually before 18 mos.) - parents are often the first to suspect that their infant is not developing motor skills normally e.g. slow to reach developmental milestones, such as learning to roll over, sit, crawl, smile, or walk

* abnormal muscle tone → hypotonia - decreased muscle tone; baby may seem flaccid and relaxed, even floppy → hypertonia - increased muscle tone; baby may seem stiff or rigid * in some cases, the baby has an early period of hypotonia that progresses to hypertonia after the first 2 to 3 months of life * may also have unusual posture or favor one side of their body * crouched gait or “scissored” gait - risk factors: a. premature birth b. low birth weight c. inability of the placenta to provide the developing fetus with oxygen and nutrients d. lack of growth factors during intra-uterine life e. RH or A-B-O blood type incompatibility between mother and infant f . infection of the mother with German measles or other viral diseases in early pregnancy g. bacterial infection of the mother, fetus or infant that directly or indirectly attack the infant's central nervous system h. prolonged loss of oxygen during the birthing process and severe jaundice shortly after birth V. Reye’s Syndrome

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

15

- primarily a children's disease, although it can occur at any age - affects all organs of the body but is most harmful to the brain and the liver - causing an acute increase of pressure within the brain and, often, massive accumulations of fat in the liver and other organs - blood sugar level typically drops while the level of ammonia and acidity in the blood rises - a two-phase illness because it generally occurs in conjunction with a previous viral infection, such as the flu or chicken pox * commonly occurs during recovery from a viral infection, although it can also develop 3 to 5 days after the onset of the viral illness - s/sx: * early persistent or continuous vomiting unusual sleepiness or lethargy * with disease progression irritable, aggressive or irrational behavior confusion weakness or paralysis in the arms and legs seizures loss of consciousness - etiology: unknown - risk factor: aspirin or salicylate-containing medications to treat viral illnesses * rule: “Don't give aspirin to anyone age 18 or younger, unless specifically recommended by the child's doctor.” * problem: “Children and teenagers who have certain chronic diseases, such as Kawasaki disease and juvenile rheumatoid arthritis, may need long-term treatment with drugs that contain aspirin. If a child needs aspirin therapy, make sure his or her vaccines are current - including two doses of the varicella (chickenpox) vaccine and a yearly flu vaccine. Avoiding these two viral illnesses can help prevent Reye's syndrome.”

chickenpox / chicken pox

flu

- diagnostic tool: no specific test for Reye's syndrome - treatment: none * management is primarily aimed at protecting the brain against irreversible damage by reducing brain swelling, reversing the metabolic injury, preventing complications in the lungs, and anticipating cardiac arrest - prognosis: >80% survival rate but may have residual brain damage can be fatal if untreated * recovery is directly related to the severity of the swelling of the brain

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

16

VI. Myasthenia Gravis > autoimmune disorder affecting the myoneural junction

> pathophysiology:

- for contraction to occur, acetylcholine from vesicles on the nerve terminal must first be released - upon release the acetylcholine must attach to the receptor sites on the motor end plate to stimulate contraction * in order to sustain muscle contraction there should be a continuous binding of acetylcholine to the receptor sites

- in MG, the post-synaptic muscle membrane loses its normal folded shape and becomes distorted and simplified resulting in the reduction of the concentration of ACh receptors on the motor (muscle) end-plate membrane - adding to the problem is the influx of antibodies which attach to the membrane which in turn result into a reduction of the available ACh receptors to which acetylcholine can attach; this does not yet include the effect of acetylcholinesterase on the released acetylcholine * antibodies are thought to originate from the thymus

the thymus is located in the upper anterior portion of the chest cavity just behind the sternum

- the overall effect is reduced transmission of impulses despite the normal release of acetylcholine from the vesicles hence the inability to sustain muscle contraction - clinically, this is manifested as muscle weakness / easy fatiguability > S/Sx: - initial manifestation involves the ocular muscles - diplopia (double vision) and ptosis (drooping of the eyelids) - with generalized muscle weakness, concern is shifted to: * decreased vital capacity - may lead to respiratory failure * dysphagia - may lead to choking and aspiration

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

17

- only the motor component is affected (does not affect sensory processes) > Dx: Edrophonium Chloride (Tensilon Test) - used to diagnose MG, and for those who are positive for MG, to differentiate between myasthenic crisis and cholinergic crisis - given through slow IV - (+) TT if there is increase in muscle strength within 30 to 60 secs. of administration and lasts for 4-5 min. - (-) TT if no improvement - Tensilon blocks the action of acetylcholinesterase thereby prolonging muscle stimulation and temporarily improving strength

> to differentiate myasthenic crisis from cholinergic crisis in a patient already taking medications for myasthenis gravis: administer Tensilon a. if the patient temporarily improves → myasthenic crisis - the patient needs more medication (underdosed)

b. if the patient temporarily worsens → cholinergic crisis - also referred to as a negative Tensilon test - client is overmedicated; give atropine sulfate (antidote) - cholinergic crisis symptoms (parasympathetic): > abdominal cramps, GI disturbances, N/V, diarrhea > miosis > HPN > ↑ bronchial secretions > ↑ salivation and tearing > sweating

> Medical Mx:

neostigmine bromide (Prostigmin)

pyridostigmine bromide (Mestinon)

ambemonium (Mytelase)

> Nursing Mx: - remind patients to take meds on time to prevent weakness because this will impair breathing and swallowing - take meds before meals for better absorption in order to maintain muscle tone for swallowing during feeding - when administering edrophonium chloride - have atropine sulfate readily available to

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

18

counteract a possible cholinergic crisis VII. Multiple Sclerosis - immune-mediated progressive demyelinating disease of the CNS - the body mistakenly directs antibodies and white blood cells against proteins in the myelin sheath, a fatty substance that insulates nerve fibers in the brain and spinal cord; this results in inflammation and injury to the sheath and ultimately to the nerves that it surrounds - the result may be multiple areas of scarring (sclerosis)

- eventually, this damage can slow or block the nerve signals that control muscle coordination, strength, sensation and vision > pathology: still unknown at the present time

> S/Sx: vary widely; depends on the location of the affected nerve fibers - numbness or weakness in one or more limbs - partial or complete loss of vision; often with pain during eye movement - double vision or blurring of vision - tingling or pain in parts of your body - electric-shock sensations that occur with certain head movements - tremor, lack of coordination or unsteady gait - fatigue - dizziness > primary diagnostic tool: MRI > Medical Mx: no known cure although at present these are some of the medications used 1. beta interferons - these drugs are genetically engineered copies of proteins that occur naturally in the body; they help fight viral infection and regulate the immune system - interferon beta-1a (Avonex, Rebif) - interferon beta-1b (Betaseron) 2. Glatiramer (Copaxone) - an alternative to beta interferons for relapsing remitting MS 3. Natalizumab (Tysabri) - blocks the attachment of immune cells to brain blood vessels - a necessary step for immune cells to cross into the brain 4. anti-neoplastic drugs > Nursing Mx: 1. assisting the physical and occupational therapists - teach patients strengthening exercises and show how to use devices that can ease the performance of daily tasks to help preserve independence 2. counseling - to help in coping with multiple sclerosis and to relieve emotional stress;

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

19

strengthen coping skills 3. teach self-care - get enough rest - fatigue is a common symptom of multiple sclerosis - exercise - improves strength, muscle tone, balance and coordination, and help with depression - be careful with heat - extreme heat may cause extreme muscle weakness; cooling down for a few hours usually will return the patient to his normal state - eat a well-balanced diet - well-balanced diet can help keep the immune system strong VIII. Guillain-Barré Syndrome - autoimmune - acute, rapid segmental demyelinization of peripheral nerves and some cranial nerves producing ascending weakness with dyskinesia (inability to execute voluntary movements), hyporeflexia, and paresthesia - weakness begins in the legs and progresses upwards

- Nursing Mx: - maintaining respiratory function - major concern * respiratory failure is the major cause of mortality - preventing contractures / enhancing mobility - passive ROM - preventing pressure sores - turning q2°

IX. Trigeminal Neuralgia (Tic Douloureux) - “tic” - twitch / “douloureux” - painful - paroxysms of pain felt in the area innervated by any of the 3 branches of CN V (trigeminal nerve) - most commonly involves the 2nd and the 3rd branches

3 branches of the trigeminal nerve

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

20

- S/Sx: unilateral, intense, stabbing, electric shock-like pain caused by irritation of the trigeminal nerve, which sends branches to the forehead, cheek, and lower jaw - pathophysiology: > the cause of the pain usually is due to contact between a normal artery or vein and the trigeminal nerve at the base of the brain; this places pressure on the nerve as it enters the brain and causes the nerve to misfire > the slightest touch can start a paroxysm

- Medical Mx: - anticonvulsant drugs have been shown to relieve the pain in most patients with TN - ex. first generation anticonvulsant ex. carbamazepine second generation anticonvulsant ex. lamotrigine X. Bell’s Palsy - facial paralysis due to unilateral inflammation of CN VII

- S/Sx: > sudden onset of paralysis or weakness on one side of the face, making it difficult to smile or to close the eye on the affected side > facial droop and difficulty with facial expressions > pain behind or in front of the ear on the affected side > sounds seem louder on the affected side > pain, usually in the ear on the affected side > headache > loss of taste > changes in the amount of tears and saliva the body produces - pathophysiology: > unknown XI. Encephaloceles - classified as neural tube defects (group of disorders occurring due to the failure of closure of the neural tube at about the 4th week of fetal development) - defect characterized by the herniation of brain tissue and membranes through an opening in the cranium

- types of encephaloceles:

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

21

a. notencephalocele (75%) - extend from the occipital region at or below the inion

b. sincipital encephalocele (25%) - extend from the orbits, nose or forehead - occur most frequently in Asians

- basal and transsphenoid encephaloceles: > rare; arise between the ethmoid and sphenoid bones and may present as an intranasal mass > may extend into the upper pharynx > neuroendocrine disturbances if the encephalocele involves the sella turcica or sphenoid sinus

- cerebral meningocele vs. cerebral encephalocele: * cerebral meningocele - consists of a CSF-filled meningeal sac only * cerebral encephalocele - portions of the brain found in the herniated meningeal sac - s/sx: * hydrocephalus * spastic quadriplegia (paralysis of all four limbs) * developmental delay * mental and growth retardation * uneven gait (ataxia) * seizures * microcephaly (abnormally small head)

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

22

* ocular hypertelorism (widespaced eyes) * cleft palate * problems with vision, breathing, and feeding XI. Spina Bifida - most common of the neural tube defects (group of disorders occurring due to the failure of closure of the neural tube at about the 4th week of fetal development) - occurs in the spine; counterpart of encephalocele in the brain - 3 types: a. spina bifida occulta - most common - “occulta” means hidden; defect is not visible - mildest form → there is a small separation or gap in one or more levels of the vertebrae - no neurologic problems because the spinal nerves are not involved - may have an abnormal tuft of hair, a collection of fat, a small dimple or a birthmark on the newborn's skin above the spinal defect

spina bifida occulta

meningocele

spina bifida cystica or myelomeningocele b. meningocele - the cyst does not contain neural elements - the membrane that surrounds the spinal cord enlarges and creates a lump or “cyst” - the cyst is often invisible and causes no problems but if the spinal canal is cleft or “bifid”, it may expand and come to the surface (skin) c. spina bifida cystica or myelomeningocele - also known as “open spina bifida” - THE form that people usually mean when they say spina bifida - neural elements protrude out of the skin; may or may not be covered by membrane - s/sx: paralysis bowel / bladder problems medical complications from infections

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

23

XII. DIAGNOSTICS Skull and Spinal X-rays

* remove the following because these can interfere with the reading: - hearing aids, dentures, hairpins, barrettes, clips, earrings or glasses, facial piercing - damp hair, tight braids, and some types of hair pieces or wigs - shirts / buttons / zippers / clips Computed Tomography (CT Scan) - ideal for bony tissues

> instruct client to hold breath when requested > inform client of mechanical noises during scanning > hot, flushed sensation and metallic taste in the mouth may be experienced when dye is injected > instruct patients to increase oral fluid intake after the procedure because diuresis from dye use (due to transient increase in renal blood flow) is expected Magnetic Resonance Imaging (MRI) - ideal for soft tissues

> remove all metals * contraindications:

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

24

cardiac pacemaker

implanted cardiac defibrillator

aneurysm clips

vascular clamp

neurostimulator

insulin or infusion pump

implanted drug infusion device

bone growth/fusion stimulator

cochlear implant

> precautions for patients attached to pulse oximeters because it can cause burns (because of electrically conductive cables and sensors; these heat up as they absorb energy) during testing if coiled around body parts > expect diuresis if contrast material is used, therefore encourage increased fluid intake

Lumbar Puncture

> also known as “spinal tap”

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

25

> needle is passed through L3-L4 or L4-L5 and into the subarachnoid space > contraindicated in patients with increased ICP because this will cause brain herniation > preprocedure nursing instruction: empty the bladder > postprocedure nursing instruction: flat on bed * positional postpuncture headache (throbbing bifrontal or occipital, dull and deep) in the strict sense begins or worsens within minutes of standing up and improves or disappears on lying down * postpuncture headache is caused by persistent leakage of CSF through a puncture-induced dural rent that may result in direct traction on intracranial pain-sensing structures and to intracranial venodilatation being apt to activate nociceptors * Queckenstedt’s test - an outdated clinical test formerly used to diagnose spinal stenosis - procedure: > with the patient in lateral decubitus position, lumbar puncture is done and the opening pressure is measured > then both jugular veins are compressed * normally the intracranial pressure must rise rapidly with compression and return quickly to normal when compression is released * if there is a slow rise and fall, this indicates a partial block; if there is no change in pressure, there is a complete block - presently, spinal stenosis is best diagnosed with MRI Myelogram Pre-procedure: > obtain an informed consent > provide hydration for at least 12hrs. before the test (side effects are related to dehydration) > assess clients for allergies to iodine or seafood (shellfish) > refer to MD regarding meds which need to be discontinued prior to testing Post-procedure: > obtain vital signs and perform neurological assessment regularly > encourage fluids and monitor intake and output > position based on contrast material used: a. water-based dye - elevate the head 15 to 30 degrees for 8 hrs. as prescribed b. oil-based dye - keep the client flat on bed for 6 to 8 hrs. as prescribed c. air - keep the head lower than the trunk for up to 48 hrs. as prescribed Cerebral Angiography

> dye is injected through the femoral artery into the carotid artery > pre-procedure NI: - hydrate for 2 days before the test

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

26

- NPO 4 to 6 hrs. prior to test - obtain baseline neuroassessment > post-procedure NI: - monitor NVS - monitor for neck swelling and difficulty of swallowing - bed rest X 12 hrs. - elevate head of bed 15 to 30° as prescribed (physiologically, this decreases the ICP; frowned upon by some MDs because of the possibility of decreasing perfusion to an already ischemic area) - keep bed flat if femoral artery was used - apply sand bags over insertion site for additional compression - place ice on puncture site Electroencephalogram (EEG) - detects problems in the electrical activity of the brain

> wash the client’s hair > inform the client that “electricity does not enter the head” > withhold stimulants, antidepressants, tranquilizers, anticonvulsants 24 to 48 hrs. before the test > no coffee, tea, cola 8 hrs. prior

NCM 104 Lec - CNS Disorders

Gener C. Sibal, RN,MD,FPOA

27