Johns Hopkins Nursing - NR.120.504.0201.SP21 Pathophysiology Neurological Miles, A & Allgood, S. (2021)

1. Neurological System
Alterations
Alison Miles, D.O.
& Sarah Allgood, PhD, RN
Modified from Susan Renda, DNP. Kristen Brown, DNP & Mathew Olson MD

2. Alterations in the Neurological System
► Pain
► Seizures
► Neuromotor and Neuromuscular disease
► Stroke and brain injury
► Infection
► Dementia

3. Vocabulary
Nocioceptors Excitatory
neurotransmitters
Inhibitory
neurotransmitters
Opioids Post-ictal
Epilepsy Convulsion Status Epilepticus Tonic/Clonic Dementia
Concussion Infarction Embolic stroke Thrombotic
stroke
Akinesia
Muscle tone
Terms
Muscle Movement
terms
Cogwheel rigidity Delirium Lower and upper
motor neuron

4. Objectives
► Define and describe seizures, including precipitating factors.
► Describe abnormalities of muscle tone and movement.
► List the 4 cardinal symptoms of Parkinson disease.
► State the significance of cerebral vascular disease and
different types of strokes.

5. Objectives
► Discuss primary and secondary brain injury,
contusion/concussion, increased ICP, and brain death vs.
cerebral death.
► Describe infections of the CNS.
► List causes of dementia.
► Differentiate between dementia and delirium.
► Pediatric variations (in module) not on test

6. Define and describe seizures, including precipitating factors.

7. Seizures
► Seizure disorders represent a manifestation of disease and
not a specific disease entity.
► A seizure is a sudden, transient disruption in brain electrical
function caused by abnormal excessive discharges of cortical
neurons. Produces a brief disruption of electrical function of
the brain and alters brain functions.
► Convulsion: sometimes applied to seizures and refers to the
tonic-clonic (jerky, contract-relax) movement associated with
some seizures.

8. Epilepsy
► Epilepsy is a disease of the brain with recurrent seizures
► Unknown cause or caused by a known epilepsy syndrome

9. Known Etiologies of Epilepsy
► Low oxygen at birth
► Head injuries
► Brian tumors
► Genetic conditions (e.g. tuberous sclerosis)
► Infections
► Stroke

10. Precipitating factors for seizures
► Hypoglycemia
► Fatigue
► Stress
► Hyponatremia
► Stimulants
► Withdrawal from depressants or alcohol
► Hyperventilation
► Environmental (lights, TV, noises, odors,…)

11. Seizure Types
► Generalized: originate on both sides of the brain
simultaneously. Motor symptoms.
► Focal: originate in one area of the brain. Can have motor or
non-motor symptoms, with or without loss of consciousness.
► Secondary generalization: starts focal, moves to general.
► Post-ictal state: follows a seizure and can include headache,
confusion, aphasia, memory loss, and paralysis that may last
hours or a day or two. Deep sleep also is common
11

12. Seizure Sequence

13. Status Epilepticus
► A state of continuous seizures lasting more than 5 minutes
OR
► A second seizure experienced before the person has fully
regained consciousness from the preceding seizure OR
► A single seizure lasts longer than 30 minutes.
► Medical emergency because of cerebral hypoxia

14. Demands during seizure activity
► Adenosine triphosphate (ATP) use is increased by 250%.
► Cerebral oxygen consumption is increased by 60%.
► Glucose is rapidly depleted
► Lactate builds up
► Cerebral blood flow also increases by approximately 250%.

15. Describe abnormalities of muscle tone and movement
.

16. Movement
► Complex patterns of activity controlled by:
• Cerebral cortex
• Pyramidal system (motor neurons from cortex to brainstem or spinal cord;
control voluntary and some involuntary movements)
• Extrapyramidal system (motor neurons controlling involuntary movements)
• Muscle motor units
► Dysfunction in any of these areas can cause motor dysfunction
► General motor dysfunction is associated with alterations in muscle tone,
movement and complex motor performance

17. Muscle Tone Abnormalities
► Hypotonia: Decreased muscle tone
► Hypertonia: Increased muscle tone
► Spasticity: Hyperexcitability of the stretch reflexes. Gradual
increase in tone that then abruptly decreases.
► Gegenhalten (paratonia): Resistance to passive movement
► Dystonia: Increased involuntary muscle contraction
► Rigidity: Firm and tense muscles; constant, involuntary muscle
contraction
• Plastic or lead pipe; cogwheel variants

18. Movement Abnormalities
► Hyperkinesia: excessive, purposeless movement. Includes tremors,
dyskinesias, chorea.
• Ex: Huntington Disease, Parkinson Disease (notably, Parkinson can also have
hypokinesia and non-motor symptoms).
► Paroxsymal dyskinesia: abnormal, involuntary movements occurring as
spasms
► Tardive dyskinesia: slow onset, involuntary movements of face, trunk,
extremities
• Most frequently a side effect of antipsychotic meds.
• Continual chewing, tongue protrusions, lip smacking, facial grimacing
► Hypokinesia: decreased movement

19. List the 4 cardinal symptoms of Parkinson disease

20. Parkinson’s Disease (PD)
► Complex motor disorder accompanied by systemic non-motor
and neurologic symptoms
► Primary and secondary causes
► The result of the loss of dopamine-producing brain cells

21. Parkinson’s Disease

22. Four Cardinal Symptoms
► Resting tremor (hand, arms, legs, jaw
and face)
► Cogwheel rigidity (stiffness of the
limbs and trunk)
► Bradykinesia/Akinesia (slowness or
absence of movement)
► Postural instability (impaired balance
and coordination)

23. Parkinson’s Disease
► Other symptoms:
• 30-40% have depression
• Cognitive impairment
• Confusion, repetitive behaviors
• Dementia develops over time
• Difficulty swallowing, chewing and speaking

24. Parkinson’s Disease
► https://www.youtube.com/watch?v=DsmSYb-DEGs

25. State the significance of cerebral vascular disease
and different types of strokes

26. Cerebral Vascular Disease
► Most frequently occurring neurologic disorder
► Any abnormality of the brain caused by a pathologic process
in the blood vessels
• Vessel wall- ex: aneurysm
• Vessel occlusion- ex: thrombus, embolism
• Vessel rupture
• Blood abnormality- ex: increased viscosity, clotting

27. Consequences of Cerebral Vascular Disease
► Ischemia with/without infarction
► Hemorrhage
► Clinical manifestation: stroke, TIA

29. Cerebral Vascular Accident-Stroke, Brain Attack
► Third-leading cause of death in the United States.
► Effects: Can range from minimal to death.
► Greatest risk factor: Hypertension
► Types
• Thrombotic or embolic ischemic stroke (87%)
• Hemorrhagic stroke

30. Ischemic Stroke
► Caused by obstruction to arterial blood flow from thrombus,
embolus from atherosclerosis or low perfusion from heart
failure/decreased blood volume
► Inadequate blood supply leads to ischemia (inadequate
oxygen delivery) and ultimately infarction (tissue death)

31. Type of Ischemic Strokes
► Thrombotic ischemic stroke
• Arterial occlusions are caused by thrombi formed in the arteries that
supply the brain or in intracranial vessels.
• Attributed to atherosclerosis and inflammatory disease processes
► Embolic ischemic stroke
• Fragments break from a thrombus formed outside of the brain
• A second stroke often occurs as the source of embolus continues to
exist.

32. ► Lacunar stroke: microinfarction is smaller than 1.5 cm in diameter;
occlusion of the small perforating arteries
► Brain hypoperfusion stroke: usually BL and diffuse. Caused by low blood
flow from cardiac failure, pulmonary embolism, blood loss, etc.
► Transient Ischemic Attack (TIA): episodes of neurologic dysfunction
lasting no more than 1 hour.
• Results from focal ischemia.
• Up to 17% of people with TIA will have a true stroke within 90 days; higher
percentage within 1 year

33. Hemorrhagic Stroke
► Can occur within the brain tissue (intraparenchymal), in
subdural or subarachnoid spaces
► Main cause of intraparenchymal hemorrhage is hypertension
► Subarachnoid hemorrhage associated with ruptured
aneurysms and other vessel anomalies
► Subdural hemorrhage usually associated with trauma
► Bleeding compresses surrounding areas leading to ischemia,
edema, increased intracranial pressure and tissue necrosis

34. Clinical Manifestations of Stroke
► Neurons surrounding the ischemic or infarcted areas undergo
changes that disrupt plasma membranes.
► Cellular edema causes compression of capillaries.
► Depend on the artery affected.
► Contralateral weakness in arms, legs, and/or face
► Possible motor, speech, and/or swallowing problems

35. Discuss primary and secondary brain injury,
contusion/concussion, increased ICP,
and brain death vs. cerebral death

36. Traumatic Brain Injury
► Alteration in brain function or other evidence of a brain pathologic
condition caused by an external force.
► Can lead to physical, intellectual, emotional, social, and vocational
changes.
► Causes:
• Falls
• Motor vehicle–related injuries
• Strike or blow to the head from or against an object
• Penetrating trauma
• Unknown

37. Types of Injury
► Primary injury
• Caused by the impact; involves neural injury, primary glial injury, vascular
responses, and shearing and rotational forces.
► Secondary injury
• Indirect consequence of the primary injury; includes a cascade of cellular
and molecular brain events.
► Tertiary injury
• Can develop days or months later, such as pneumonia, fever, infections,
and immobility, which contributes to further brain injury or delays repair.
Hallmark of severe brain injury is the loss of consciousness for 6
or more hours.

39. Contusion
► Brain bruise; blood leaking from a damaged vessel
► Caused by compression of the skull
► Coup (at the point of impact) or countercoup (opposite side,
from the brain rebounding off the opposite side of the skull)
► More severe in smaller areas of impact because the forec is
more concentrated
► Edema forms around the contusion, as can hemorrhages,
infarction, and necrosis

40. Glasgow Coma Scale (GCS)

41. Mild TBI
► Mild concussion; GCS 13-15
► Immediate but temporary effects
► No loss of consciousness (LOC) or LOC <30 min
► Headache, nausea, memory problems, dizziness, inability to
concentrate, confusion.
► Anterograde amnesia (inability to make new memories,
leading to short-term memory loss) for up to 24 hours is
possible

42. Moderate TBI
► Moderate concussion; GCS 8-13
► LOC > 30 min with anterograde amnesia lasting 24 hours or
more
► Confusion and memory loss plus unconsciousness are
prominent features
► Often results in permanent deficits in attention, memory, data
processing, vision, perception, and/or language. Mood
changes occur and range from mild-severe.

43. Severe TBI
► Severe concussion; GCS <8
► Associated with signs of brainstem injury (pupil changes, HR
and respiratory effects, posturing) and intracranial contusions,
hematomas and lacerations
► LOC >24 hours
► Increased intracranial pressure evident within 3-6 days
► Permanent deficits in cognition, movement, learning,
language. Up to 14% remain in vegetative state, 20-40% die

44. Epidural Hematoma
► Bleeding between dura and skull, usually from arterial source
► High volume bleed most often requiring emergent surgery
► Pts can have initial LOC, regain consciousness then have
recurrent LOC and rapid decline hours later as blood
accumulates
► Usually result from motor vehicle accidents, sometimes sports
injuries
► 1-2% of major head injuries

45. Epidural Hematoma

46. Subdural Hematoma
► Bleeding between dura and brain
► 10-20% of TBIs
► Caused by bleeding from veins. Usually occur at the top of
the skull.
► Can be acute or chronic
► As ICP rises, bleeding veins are compressed, limiting
bleeding. Compression of surrounding tissues can occur.

47. Subdural Hematoma

48. Intracerebral Hematoma
► Bleeding within brain
► 2-3% of head injuries
► Caused by small vessel injury from penetrating trauma or
shearing forces
► Hematoma expands, compressing surrounding structures,
increasing ICP, causing ischemia

49. Intracerebral Hematoma

50. Increased Intracranial Pressure
► Normal is 5 to 15 mm Hg.
► Is caused by increased intracranial content.
• Tumor growth
• Edema
• Excessive cerebrospinal fluid
• Hemorrhage

51. Increased Intracranial Pressure
Stage 4
Brain herniates; several herniation syndromes
Stage 3
Brain hypoxia and hypercapnia; autoregulation lost
Stage 2
Continued expansion of intracranial content
Stage 1
Vasoconstriction and external compression

52. Intracranial Hypertension (Increased ICP)

53. Herniation
► Consequence of increased ICP
► Shifting of brain tissue from compartment of greater pressure
to one with lesser pressure.
• Disrupts blood flow and further damages herniating brain tissue
• Process rapidly and markedly increases ICP further
• Mean systolic BP will bcome equal to ICP and cerebral blood flow
will stop

54. Herniation Syndromes
► Supratentorial; involves the temporal lobe and hippocampal gyrus,
shifting from the middle fossa to the posterior fossa.
► Transtentorial: downward shift of the diencephalon through
the tentorial notch.
► Cingulate gyrus: shifting under the falx cerebri
► Infratentorial: shift of the cerebellar tonsils through the
foramen magnum.

56. Decorticate:
Hemispheric damage above
the midbrain
Decerebrate:
Severe damage to
diencephalon or midbrain

57. Cerebral Death
► Irreversible coma
► Death of the cerebral hemispheres, exclusive of the brainstem
and cerebellum
► No behavioral or environmental responses
► Brain continues to maintain normal respiratory and
cardiovascular functions, temperature control, and
gastrointestinal functioning

58. Brain Death
► Irreversible loss of all brain functions including the brainstem.
• Lack of motor or autonomic responses to noxious stimulation.
• Absence of cranial nerve reflexes and spontaneous breathing.
► Irreversibility:
• The cause of coma is established and is sufficient to account for
permanent loss of brain function.
• The possibility of recovery of any brain function is excluded by
observation for an appropriate period of time.

59. Exam Components
► Coma
• Lack all responsiveness other than spinal reflexes
► Absence of brainstem reflexes
• Pupillary response BL (II, III)
• Ocular movements- oculocephalic (III, IV, VI) and oculovestibular (III, VI,
VIII)
• Corneal reflexes BL (V, VII)
• Facial muscle movement (V, VII)
• Pharyngeal and tracheal reflexes (gag and cough) (IX, X)
► Apnea test

60. Brain Death vs. Cerebral Death
► Brain has no potential for
recovery and can no longer
maintain the body’s internal
homeostasis.
► State laws:
• Entire brain, brainstem,
and cerebellum stops functioning.
• Brain is autolyzing (self-digesting) or
has already autolyzed on postmortem
examination.
Brain Death Cerebral Death
► Death of the cerebral
hemispheres is exclusive
of the brainstem and cerebellum.
► Brainstem may continue
to maintain internal homeostasis
(normal respiratory and
cardiovascular functions,
temperature control, and
gastrointestinal function).

61. Describe infections of the CNS

62. Meningitis
► Inflammation of brain or spinal cord
► Infection in the subarachnoid space; viral, bacterial, fungal,
parasitic
► Recovery depends on prompt treatment with antimicrobials
(other than when viral)
► Symptoms
• Headache
• Fever
• Stiff neck
• Cerebral dysfunction

63. Encephalitis
► Inflammation of the brain
► Symptoms vary from mild (fever, HA) to severe (coma,
seizures)
► Most common forms are caused by insect bites; most
common viral cause is HSV-1
► Treatment supportive unless etiology is herpes
• Acyclovir

64. Brain Abscess
► Mostly bacterial
► Necrotizing infections from neighboring structures (teeth,
sinuses, ears) or penetrating wounds
► Starts with low-grade fever, HA, nausea/vomiting, drowsiness
► Later manifestations caused by mass effect- decreased
attention, memory deficits, vision problems, ataxia, seziures
► Treatment: surgical drainage and antibiotics

65. List causes of dementia

66. Dementia
► Acquired deterioration and progressive failure of many
cerebral functions. Impairment in intellectual functions,
orientation, memory, judgment, decision-making.
► Behavioral changes can happen due to intellectual decline:
aggression, wandering, agitation.

67. Causes of Dementia
► Neurodegeneration (Alzheimer’s, Parkinson’s etc.)
► Atherosclerosis (vascular dementia)
► Trauma
► Tumors
► Increased ICP
► Metabolic disorders, vitamin deficiencies
► Others

68. Differentiate between dementia and delirium

69. Delirium
► Transient disorder of awareness. Can have sudden or gradual onset.
► Often secondary to something: illness, intoxication, electrolyte imbalance,
dehydration, etc.
► Hyperactive, hypoactive or mixed
► Difficulty concentrating, focusing attention, restlessness, irritability,
insomnia, tremulousness, poor appetite. Hallucinations or delusions can
occur.
► With hypoactive delirium, patient has decreased alertness, attention span,
confusion, slow speech, frequent dozing off. Can be confused with
depression or dementia.

70. Comparison of
Delirium and
Dementia

71. Alterations in Arousal
State Definition
Confusion Loss of the ability to think rapidly and clearly; impaired judgment and decision making
Disorientation Beginning loss of consciousness; disorientation to time, followed by disorientation to place and impaired
memory; recognition of self is lost last
Lethargy Limited spontaneous movement or speech; easy arousal with normal speech or touch; may not be
oriented to time, place, or person
Obtundation Mild-to-moderate reduction in arousal (awakeness) with limited response to the environment; falls asleep
unless verbally or tactilely stimulated; answers questions with minimum responses
Stupor Condition of deep sleep or unresponsiveness; person may be aroused or caused to open eyes only by
vigorous and repeated stimulation; response is often withdrawal or grabbing at stimulus
Coma No verbal response to the external environment or to any stimuli; noxious stimuli such as deep pain or
suctioning yields motor movement
Light coma Associated with purposeful movement on stimulation
Deep coma Associated with unresponsiveness or no response to any stimulus