Neurology and Brain Disorders Flashcards

Major Functional Areas of the Brain

• Frontal Lobe

  • Prefrontal Area (Left Cortex): Responsible for intellectual function and personality.

  • Premotor Cortex: Controls skilled movements.

  • Motor Cortex: Responsible for voluntary movements. It is mapped to specific body parts including the foot, leg, trunk, arm, hand, and face.

  • Broca's Area (Left Cortex): Involved in speech expression.

• Parietal Lobe

  • Somatosensory Area: Processes sensations such as touch and pain. It receives and localizes basic sensory input.

• Occipital Lobe

  • Visual Cortex: Responsible for vision.

  • Visual Association Area: Processes visual information.

• Temporal Lobe

  • Auditory Cortex: Responsible for hearing.

  • Olfactory Cortex: Responsible for smell.

  • Wernicke's Area (Left Cortex): Responsible for the comprehension of speech and memory.

• Cerebellum: Controls body balance, position, equilibrium, and coordinated movement.

• Brainstem (Medulla Oblongata, Pons, Midbrain)

  • Medulla Oblongata: Contains vital centers for control and coordination of respiration and cardiovascular activity. It serves as the reflex center for swallowing, vomiting, and coughing. Contains nuclei of five cranial nerves.

  • Pons: Part of the vital centers and connects different parts of the brain.

  • Reticular Activating System (RAS): Responsible for arousal, awareness, and level of consciousness.

• Diencephalon and Deep Nuclei

  • Thalamus: Serves as the sensory sorting and relay center.

  • Hypothalamus: Links with the endocrine system; controls body temperature and fluid balance; contains centers for thirst and hunger.

  • Basal Nuclei: Involved in the coordination and control of body movement.

  • Limbic System: Responsible for emotional responses.

The Spinal Cord and Autonomic Nervous System

• The Spinal Cord Structure

  • Cervical ($C-1$ to $C-8$): Includes the Phrenic nerve ($C-3$ to $C-5$) to the diaphragm for respiration. Controls arms.

  • Thoracic ($T-1$ to $T-12$): Includes Intercostal muscles for respiration ($T-1$ to $T-7$). Sympathetic nervous system fibers ($T-1$ to $L-2$) control heart, temperature, and blood vessels.

  • Lumbar ($L-1$ to $L-5$): Controls legs.

  • Sacral ($S-1$ to $S-5$): Parasympathetic nerves control bowel, bladder, and external genitalia.

• Autonomic Nervous System (ANS) Stimulation Effects

  • Cardiovascular System

    • Heart: Sympathetic ($\beta-1$) increases rate and force of contractions; Parasympathetic decreases rate and contractility.

    • Blood Vessels (Skin, Mucosa): Sympathetic ($\alpha-1$) causes vasoconstriction.

    • Skeletal Muscle Vessels: Sympathetic ($\beta-2$) causes vasodilation.

  • Adrenal Medulla: Sympathetic stimulation causes secretion of epinephrine and norepinephrine.

  • Respiratory System: Sympathetic ($\beta-2$) causes bronchodilation; Parasympathetic causes bronchoconstriction.

  • Eye: Sympathetic ($\alpha-1$) causes pupil dilation (radial muscle); Parasympathetic causes pupil constriction (sphincter).

  • Digestive System: Sympathetic decreases secretions and peristalsis ($\alpha-2$), and constricts sphincters ($\alpha-1$); Parasympathetic increases secretions/peristalsis and relaxes sphincters.

  • Urinary System: Sympathetic ($\alpha-1$) constricts bladder sphincters and increases renin secretion ($\beta-1$); Parasympathetic relaxes sphincters.

  • Male Genitalia: Sympathetic ($\alpha-1$) causes ejaculation; Parasympathetic causes erection.

Hemispheric Specialization and Consciousness

• Hemispheric Damage

  • Left Hemisphere Damage: Results in loss of logical thinking, analytical skills, intellectual abilities, and communication skills.

  • Right Hemisphere Damage: Impairs appreciation of music and art; causes behavioral problems; leads to deficient spatial orientation and recognition of relationships; self-care deficits are common.

• Levels of Reduced Consciousness

  • Confusion and Disorientation: Beginning loss of consciousness; first to time, then place/memory, last to self-recognition.

  • Lethargy: Limited spontaneous movement/speech; easily aroused; may or may not be oriented.

  • Obtundation: Mild to moderate reduction in arousal; limited environmental response; falls asleep without constant stimulation; minimum response to questions.

  • Stupor: Deep sleep condition; arouses only to vigorous stimulation; responds by withdrawing or grabbing stimulus.

  • Coma: No verbal response to any stimuli.

    • Light Coma: Purposeful movement only with extreme stimulus.

    • Deep Coma: Total unresponsiveness.

  • Vegetative State: Loss of awareness and mental capabilities due to diffuse brain damage; brainstem function continues (sleep-wake cycle present) but the person is unresponsive.

  • Locked-in Syndrome: Individual is aware and capable of thinking but is paralyzed and cannot communicate.

• Criteria for Brain Death

  • Cessation of brain function (cortex and brainstem).

  • Flat or inactive EEG.

  • Absence of brainstem reflexes and spontaneous respirations.

  • Certainty of irreversible damage; evaluated twice by different physicians.

Neurological Assessment and Motor/Sensory Dysfunction

• Glasgow Coma Scale (GCS)

  • Eye Opening ($1-4$): Spontaneous ($4$) to None ($1$).

  • Motor Response ($1-6$): Obeys commands ($6$) to None/Flaccid ($1$).

  • Verbal Response ($1-5$): Oriented ($5$) to None ($1$).

  • Scores: $15$ is normal/good; low scores (e.g., $4$) indicate severe impairment.

• Motor Dysfunction

  • Upper Motor Neuron (UMN) Damage: Interference with voluntary movement; weakness/paralysis on the contralateral side.

  • Lower Motor Neuron (LMN) Damage: Weakness/paralysis on the same side at and below the level of damage.

  • Decorticate Posturing (Flexor): Arms move toward the "cord" (like "Cs"); indicates problems with the cervical spinal tract or cerebral hemisphere.

  • Decerebrate Posturing (Extensor): Arms are like "Es"; indicates problems within the midbrain or pons.

• Sensory and Visual Deficits

  • Dermatomes: Areas of skin mapped to specific spinal nerves used to evaluate spinal cord lesions.

  • Hemianopia: Visual field loss.

    • Optic Chiasm Damage: Total or partial loss in both eyes.

    • Optic Tract/Occipital Lobe Damage: Loss of visual field on the side opposite to the damage.

Language Disorders

• Aphasia

  • Expressive (Broca area): Damage to left frontal lobe; impaired ability to speak/write fluently.

  • Receptive (Wernicke area): Damage to left temporal lobe; inability to understand written or spoken words.

  • Global: Combination of expressive and receptive; involves major brain damage to Broca, Wernicke, and connecting fibers.

  • Fluent Aphasia: Normal pace but uses made-up words (Wernicke damage).

  • Non-fluent Aphasia: Slow, labored speech with short phrases (Broca damage).

• Other Disorders

  • Dysarthria: Inability to articulate words clearly due to motor/cranial nerve damage.

  • Agraphia: Impaired writing ability.

  • Alexia: Impaired reading ability.

  • Agnosia: Loss of recognition or association.

Increased Intracranial Pressure (IICP)

• Causes: Increase in brain tissue ($80-85\%$), blood volume ($5-10\%$), or CSF ($10\%$).

• Pathophysiology: Traumatic injury leads to swelling/bleeding $→$ increase in intracranial volume $→$ rigid cranium prevents expansion $→$ IICP $→$ pressure on blood vessels $→$ cerebral hypoxia/ischemia $→$ brain herniation $→$ cessation of blood flow.

• Compensation (Autoregulation): CSF is shunted to the spinal cord; hyperventilation causes cerebral vasoconstriction via decreased $CO_2$.

• Stages of IICP

  • Stage 1 & 2: Stable vitals, small reactive pupils; Intervention is most effective here.

  • Stage 3 & 4 (Decompensation): Coma, ipsilateral or bilateral pupil dilation/fixation, Cheynes-Stokes or ataxic breathing, increasing systolic pressure with widening pulse pressure, bradycardia (Cushing's reflex).

• Herniation Types: Transtentorial, Uncal (temporal lobe into tentorial notch), Infratentorial (cerebellar/tonsillar).

Vascular Disorders and Stroke

• Transient Ischemic Attacks (TIAs): Temporary localized reduction of blood flow; symptoms (paresis, aphasia, visual blur) are short-lived warning signs for a stroke.

• Cerebrovascular Accident (CVA/Stroke): Infarction of brain tissue. $5\,minutes$ of ischemia causes irreversible damage.

  • Thrombus: Gradual onset (often at rest); minimal IICP; localized damage.

  • Embolus: Sudden onset; localized unless multiple emboli are present.

  • Hemorrhage: Sudden onset (often with activity); high IICP; widespread, severe, and often fatal effects.

• Emergency Treatment: Call $911$ immediately; rapid transport is critical as time relates directly to brain damage severity.

Head and Spinal Cord Injuries

• Head Injuries

  • Concussion: Reversible, sudden brain movement; recovery in $24\,hours$.

  • Contusion: Bruising of brain tissue with edema and vessel rupture.

  • Closed vs. Open: Closed (skull intact); Open (skull fractured/penetrated).

  • Basilar Fracture: Base of skull; may cause CSF leakage from ears/nose.

  • Contrecoup: Injury on the side opposite the impact as the brain bounces.

• Hematomas

  • Epidural: Bleeding between dura and skull; rapid onset within hours.

  • Subdural: Bleeding between dura and arachnoid; acute or subacute.

  • Subarachnoid: Bleeding between arachnoid and pia; blood mixes with CSF.

  • Intracerebral: Results from contusions/shearing; may develop days later.

• Spinal Cord Injury (SCI)

  • Mechanisms: Hyperflexion, Hyperextension, Compression.

  • Spinal Shock: Initial period where all neurologic activity and reflexes cease below the injury (flaccid paralysis).

  • Autonomic Dysreflexia: Massive sympathetic response below injury triggered by stimuli (e.g., bladder distention). Causes extreme hypertension, bradycardia (vagus nerve response), and vasodilation above the injury.

Seizure Disorders

• Etiology: $70\%$ are idiopathic; others caused by lesions, trauma, or biochemical disorders.

• Phases of a Seizure

  • Prodroma: Hours/days before (headache, irritability).

  • Aura: Sensory warning (visual, auditory, olfactory).

  • Ictal Phase: The seizure itself.

    • Tonic: Muscles stiffen; cyanosis.

    • Clonic: Limbs jerk; salivation.

  • Postictal: Recovery; sleepiness and confusion.

• Status Epilepticus: Seizure lasting more than $5-10\,minutes$ or recurrent seizures without regaining consciousness in between.

• Frontal Lobe

  • Prefrontal Area (Left Cortex): Responsible for intellectual function and personality.

  • Symptoms: Mental confusion, personality changes, difficulty with problem-solving.

  • Nursing Interventions: Assess cognitive function regularly, provide a structured environment, and offer cognitive therapy.

  • Premotor Cortex: Controls skilled movements.

  • Symptoms: Difficulty planning or executing movements.

  • Nursing Interventions: Encourage physical therapy and occupational therapy.

  • Motor Cortex: Responsible for voluntary movements.

  • Symptoms: Weakness or paralysis in specific limbs.

  • Nursing Interventions: Assist with mobility and exercises to strengthen affected areas.

  • Broca's Area (Left Cortex): Involved in speech expression.

  • Symptoms: Difficulty speaking or forming sentences.

  • Nursing Interventions: Facilitate communication through speech therapy, use of communication devices.

• Parietal Lobe

  • Somatosensory Area: Processes sensations such as touch and pain.

  • Symptoms: Numbness or tingling sensations, altered perception of touch.

  • Nursing Interventions: Monitor sensation changes, educate on safety, and encourage sensory stimulation activities.

• Occipital Lobe

  • Visual Cortex: Responsible for vision.

  • Symptoms: Visual disturbances, blurred vision.

  • Nursing Interventions: Assess vision regularly, provide a safe environment.

• Temporal Lobe

  • Auditory Cortex: Responsible for hearing.

  • Symptoms: Hearing loss or distortion.

  • Nursing Interventions: Monitor hearing capabilities, refer for audiologic evaluations.

  • Olfactory Cortex: Responsible for smell.

  • Symptoms: Loss of smell sensation.

  • Nursing Interventions: Assess for changes in smell and educate on safety risks.

  • Wernicke's Area (Left Cortex): Responsible for comprehension of speech and memory.

  • Symptoms: Difficulty understanding spoken or written language.

  • Nursing Interventions: Support communication and comprehension through tailored education strategies.

• Cerebellum

  • Controls body balance, position, equilibrium, and coordinated movement.

  • Symptoms: Coordination problems, unsteadiness.

  • Nursing Interventions: Implement balance and coordination exercises, and provide assistive devices if needed.

• Brainstem (Medulla Oblongata, Pons, Midbrain)

  • Medulla Oblongata: Contains vital centers for control and coordination of respiration and cardiovascular activity.

  • Symptoms: Respiratory distress, abnormal heart rhythms.

  • Nursing Interventions: Monitor vital signs, maintain airway, and provide oxygen if needed.

  • Pons: Part of the vital centers and connects different parts of the brain.

  • Reticular Activating System (RAS): Responsible for arousal, awareness, and level of consciousness.

  • Symptoms: Altered consciousness levels.

  • Nursing Interventions: Monitor level of consciousness and provide a calm environment to promote awareness.

• Diencephalon and Deep Nuclei

  • Thalamus: Serves as the sensory sorting and relay center.

  • Hypothalamus: Links with the endocrine system; controls body temperature and fluid balance.

  • Symptoms: Temperature dysregulation, abnormal thirst or hunger.

  • Nursing Interventions: Monitor fluid intake/output and body temperature, educate on managing symptoms.

  • Basal Nuclei: Involved in coordination and control of body movement.

  • Limbic System: Responsible for emotional responses.

  • Symptoms: Mood swings, emotional instability.

  • Nursing Interventions: Educate and support emotional management strategies, monitor mood changes.

• Scenario 1: Patient with Frontal Lobe Injury
  Patient exhibits significant personality changes and difficulty with problem-solving.

  • Nursing Intervention: Regularly assess cognitive function and provide a structured environment.
  • Rationale: Structured environments can help patients with frontal lobe injuries feel more secure and reduce confusion, providing them with predictable routines that may aid cognitive function.

• Scenario 2: Patient with Motor Cortex Damage
  Patient presents with weakness in their right arm and difficulty executing voluntary movements.

  • Nursing Intervention: Assist with mobility and implement occupational therapy.
  • Rationale: Occupational therapy focuses on regaining strength and improving the patient's functional abilities, which is vital for their independence and quality of life.

• Scenario 3: Patient with Wernicke's Aphasia
  Patient has difficulty understanding spoken language and responds in a nonsensical manner.

  • Nursing Intervention: Support communication efforts by using visual aids and encourage speech therapy sessions.
  • Rationale: Visual aids can assist in bridging communication gaps, while speech therapy focuses on restoring language comprehension and expression skills.

• Scenario 4: Patient with Cerebellar Dysfunction
  Patient shows signs of unsteadiness and coordination problems.

  • Nursing Intervention: Implement balance and coordination exercises and provide assistive devices as needed.
  • Rationale: Physical therapy and assistive devices can enhance mobility and safety, reducing fall risks and supporting physical rehabilitation.

• Scenario 5: Patient with Reticular Activating System Compromise
  Patient is in a confused state and shows altered levels of consciousness.

  • Nursing Intervention: Monitor level of consciousness regularly and create a calming environment.
  • Rationale: A calm environment can promote awareness and assist in stabilizing the patient’s consciousness levels, as stress can exacerbate confusion and disorientation.