Oncologic and Degenerative Neurologic Disorders Study Guide

Introduction to Oncologic and Degenerative Neurologic Disorders

• Overview: This topic covers the management of patients experiencing brain or nerve problems resulting from cancer (oncologic) or progressive conditions that deteriorate over time (degenerative).

• Oncologic Disorders of the Brain and Spinal Cord: These involve cancers affecting the central nervous system (CNS), either originating there or spreading from elsewhere.

• General Clinical Manifestations:     - Headheads.     - Seizures.     - Weakness.     - Personality changes.

• Importance of Early Detection: Early diagnosis and treatment are critical for patient outcomes.

Brain Tumors: Classification and Pathophysiology

• Primary Brain Tumors: These tumors originate directly within the brain tissue.

• Secondary (Metastatic) Brain Tumors: These develop from cancer in other parts of the body—such as the lungs or breasts—and spread to the brain.

• Why Tumors Cause Problems:     - Inflammation: Tumors trigger inflammatory responses.     - Compression: They exert pressure on nearby brain structures.     - Infiltration: They invade and replace normal brain tissue.

• Key Physical Changes Caused by Tumors:     - Increased Intracranial Pressure ($ICP$) and Cerebral Edema: Because the skull is a closed space with a fixed volume, any tumor mass takes up space, raising pressure. This results in headaches and changes in consciousness.     - Seizure Activity and Focal Signs: Tumors irritate brain cells and disrupt normal electrical signals among neurons, leading to seizures, weakness, or confusion.     - Hydrocephalus: A tumor may physically block the flow of cerebrospinal fluid ($CSF$). This blockage causes the ventricles to enlarge and increases $ICP$.     - Altered Pituitary Function: Tumors near the base of the brain can damage the pituitary gland, disrupting the production of hormones that control diverse body functions.

• Tumor Characterization:     - Benign: Non-cancerous tumors (e.g., colloid cysts). While not malignant, they remain dangerous if they compress vital brain areas.     - Malignant: Cancerous, aggressive tumors that grow rapidly and are difficult to remove completely.

Classification of Brain Tumors by Cell Type

• Gliomas: Tumors that originate from glial cells (support cells in the brain). This is the most common type of brain tumor in adults.     - Astrocytoma: Derived from star-shaped glial cells called astrocytes.         - Grades $1$ and $2$: Low-grade, slow-growing tumors.         - Glioblastoma (Grades $3$ or $4$ astrocytoma): Highly malignant, rapidly dividing, immature cells with a poor prognosis.     - Oligodendroglioma: Derived from oligodendrocytes (cells that produce myelin in the CNS). These often respond better to chemotherapy than astrocytomas.     - Ependymoma: Arises from ependymal cells lining the ventricles and spinal canal. Frequently causes hydrocephalus by blocking $CSF$ flow, particularly in children.

• Non-Glial Tumors: Arise from tissues surrounding the brain, not the brain cells themselves.     - Meningioma: Benign, slow-growing tumors arising from the meninges (the protective layers of the brain). Often grow near venous sinuses.     - Acoustic Neuroma (Vestibular Schwannoma): Arises from the eighth ($8^{th}$) cranial nerve (vestibulocochlear nerve). Early signs include hearing loss, tinnitus, and loss of balance.     - Pituitary Adenoma: Benign tumors of the glandular tissue in the pituitary gland.         - Physical effects: Compression of the optic chiasm leads to vision problems, specifically loss of peripheral vision.         - Hormonal effects:             - Prolactin excess: Leads to galactorrhea (spontaneous milk flow) and menstrual issues.             - Growth Hormone excess: Causes acromegaly in adults.             - Adrenocorticotropic Hormone ($ACTH$) excess: Causes Cushing’s syndrome.             - Thyroid Stimulating Hormone ($TSH$) excess: Causes hyperthyroidism.

Clinical Manifestations and Localization

• Common Tumor Sites:     - Corpus Callosum/Cerebrum: Affects cognition, speech, movement, or personality.     - Ventricular Areas: Blocks $CSF$ flow.     - Optic Chiasm: Causes visual field loss.

• General Symptoms:     - Headache: Most common, often worse in the morning.     - Vomiting: Caused by irritation of the vagal centers in the medulla.     - Visual Disturbances: Often due to compression of the third ($3^{rd}$) cranial nerve.

• Lobe-Specific Manifestations:     - Frontal Lobe: Hemiparesis (weakness on one side), partial seizures on the opposite side of the body.     - Parietal Lobe: Decreased sensation on the opposite side, sensory deficits.     - Temporal Lobe: Memory loss, mood changes, psychological symptoms, and seizures.     - Occipital Lobe: Vision loss or hallucinations.     - Cerebellar Lobe: Unsteady gait, dizziness, and loss of balance.     - Cerebellopontine Angle: Tinnitus and vertigo ($8^{th}$ cranial nerve involvement).     - Brain Stem: Cranial nerve deficits and complex sensory/motor problems.

Diagnostic Procedures and Medical Management

• Diagnostic Tools:     - CT Scan: Shows number, size, and density of lesions; identifies bleeding.     - MRI: Gold standard for soft tissue detail and small lesions.     - Stereotactic Biopsy: A $3D$-guided tool to sample tissue from hard-to-reach areas to confirm tumor type.     - PET Scan: Determines if a tumor is malignant, active, or inactive.     - EEG: For patients with seizures or unexplained behavior.     - Cytologic Studies of $CSF$: Checks for malignant cells in the fluid.

• Surgical Management:     - Craniotomy: Surgical opening of the skull to remove as much of the tumor as safely possible.

• Radiation Therapy:     - Gamma Radiation: Focused destruction of tumor cells.     - Brachytherapy: Radioactive material placed directly inside or near the tumor.     - Radioisotopes: Internal radiation via injection or implantation.

• Pharmacotherapy:     - Temozolomide: An oral chemotherapy drug used for glioblastoma.     - Corticosteroids (e.g., Dexamethasone): Reduce cerebral edema and lower high $ICP$.     - Mannitol: An osmotic diuretic used to rapidly lower $ICP$.     - Anticonvulsants: To prevent or control seizure activity.

• Other Treatments: Autologous bone marrow transplantation to replace marrow damaged by high-dose chemotherapy.

Nursing Management for Brain Tumors and Metastasis

• Patient Safety:     - Reorient the patient to person, time, and place to manage confusion.     - Implement seizure precautions: Pad side rails and keep the bed in a low position to prevent injury.

• Nutritional Support:     - Evaluate gag reflex and swallowing pre-operatively.     - Teach patients to chew on the unaffected side of the mouth to prevent aspiration.     - Maintain suction at the bedside if the gag reflex is weak.     - Record daily weights and quantity of food eaten ($daily$).     - Use parenteral nutrition ($NGT$ or $OGT$) if dysphagia is present.

• Neurological Monitoring: Frequent neuro checks and vital sign monitoring to detect shifts in $ICP$.

• Psychosocial Support: Allow the patient to communicate fears regarding death or change in appearance; encourage independence to maintain dignity.

• Cerebral Metastasis Support: When cancer spreads from the lungs or breast, the goal shifts to palliative care.     - Palliation: Focuses on comfort, pain relief (e.g., Morphine), and quality of life.     - Intrathecal Chemotherapy: Drugs delivered directly into the $CSF$ because systemic drugs often cannot cross the blood-brain barrier.

Spinal Cord Tumors

• Classification by Location:     - Intramedullary Lesions: Grow inside the spinal cord; damage motor and sensory tracts.     - Extramedullary - Intradural: Inside the dura mater but outside the cord; press on the cord from the outside.     - Extradural: Located in the vertebrae; often metastatic.

• Clinical Manifestations:     - Symptoms usually appear below the level of the lesion.     - Localized or shooting (radicular) pains.     - Progressive weakness, loss of reflexes, or paralysis.     - Loss of bowel and bladder control (urinary retention/incontinence).

• Management:     - Dexamethasone: High-dose corticosteroids to reduce inflammation.     - Surgery: Resection to reverse neurological deficits.

• Post-Operative Nursing Care:     - Log Rolling: Turn the patient as a single unit, keeping shoulders and hips aligned and the back straight. Use a pillow between the knees.     - Monitor for Pseudomeningocele: Bulging at the incision site that may indicate a $CSF$ leak requiring surgical repair.     - Assess for asymmetric chest movement or abdominal breathing.

Parkinson's Disease ($PD$)

• Definition: A slowly progressive movement disorder caused by the loss of dopamine-producing neurons in the Substantia Nigra.

• Pathophysiology:     - Loss of Dopamine: Results in an imbalance with Acetylcholine (an excitatory neurotransmitter).     - Movement disruption: Acetylcholine overstimulates muscles because the inhibitory signal (dopamine) is missing.

• Cardinal Signs of Parkinson's:     1. Tremor: Often "pill-rolling" tremor of the hands; occurs at rest and disappears during sleep/movement.     2. Rigidity: Stiffness of limbs/face; "cogwheel rigidity" (resistance to passive movement in a jerky way).     3. Bradykinesia: General slowness of movement; "freezing phenomenon" (feet feel glued to the floor).     4. Postural Instability: Stooped posture, forward-leaning, and "Parkinsonian gait" (short, shuffling steps).

• Other Manifestations:     - Non-motor: Excessive sweating, orthostatic hypotension, and gastric/urinary retention.     - Psychiatric: Depression, anxiety, and dementia.     - Physical: Micrographia (progressively smaller handwriting), mask-like face, dysphonia (soft/monotone voice), and dyskinesia.

• Medical Management:     - Levodopa: converted to dopamine in the brain. Often used as a diagnostic "Levodopa trial."     - Carbidopa: Added to Levodopa to prevent it from being broken down before reaching the brain.     - Deep Brain Stimulation ($DBS$): Surgical implantation of electrodes to regulate motor control when medication is no longer sufficient.     - Neural Transplantation: Research-level transplantation of pig, fetal, or stem cells (ethically controversial).

Huntington's Disease ($HD$)

• Definition: A chronic, progressive, hereditary disorder (Huntington's Chorea) involving the breakdown of nerve cells in the brain.

• Genetics: Autosomal dominant genetic disorder located on Chromosome $4$. If a parent has it, offspring have a $50\%$ chance of inheritance.     - Confirmatory Test: $CAG$ repeat marker. Normal is $10-35$ repeats; $HD$ is $36$ or more repeats.

• Pathophysiology: Mutation in the Huntington gene leads to an abnormal buildup of glutamine, causing premature neuron death in the basal ganglia and cerebellum.

• Clinical Manifestations:     - Chorea: Involuntary, jerky, "dance-like" movements.     - Cachexia: Severe emaciation due to constant movement and high caloric burn.     - Intellectual Decline: Progresses to dementia.     - Speech: Slurred, hesitant, or explosive.

• Nursing Care:     - Nutrition: High-protein, high-calorie diet. Use a long-handled spoon; place the spoon in the middle of the tongue with slight pressure.     - Safety: Remove sharp furniture; use padded headboards and elbow protectors to prevent skin breakdown.     - Psychosocial: Genetic counseling for the family.     - Medication: Tetrabenazine (FDA-approved for chorea) to lower dopamine.

Amyotrophic Lateral Sclerosis ($ALS$)

• Definition: Also known as Lou Gehrig's disease. It is a progressive degeneration of motor neurons in the brain and spinal cord.

• Characteristics:     - Amyotrophic: Muscle atrophy.     - Lateral Sclerosis: Scarring/hardening of the lateral columns of the spinal cord.

• Clinical Manifestations:     - Muscle weakness starting in the hands, feet, or legs.     - Fasciculations (involuntary muscle twitching).     - Bulbar Symptoms: Difficulty speaking ($dysarthria$) and swallowing ($dysphagia$).     - Preservation of Senses: The patient remains mentally alert while the body paralyzes.

• Management:     - Riluzole ($Rilutex$): Glutamate antagonist; extends survival by $3$ to $6$ months but is highly hepatotoxic (requires liver function tests).     - Spasticity: Managed with Baclofen, Dantrolene, or Diazepam.     - Ventilation: Eventually requires mechanical ventilation and $PEG$ tube feeding.

Muscular Dystrophy and Degenerative Disc Disease ($DDD$)

• Muscular Dystrophy: Incurable skeletal muscle wasting.     - Duchenne Muscular Dystrophy ($DMD$): Most common variant. Identifiable by high serum levels of Creatinine Kinase.     - Management: Mobility preservation, night splints, and genetic counseling.

• Degenerative Disc Disease ($DDD$):     - Pathophysiology: Discs between vertebrae deteriorate and bulge or rupture (herniation), compressing nerve roots.     - Symptoms: Radiculopathy (pain radiating down arms/legs), numbness, and tingling.     - Surgical Interventions:         - Laminectomy: Removing the lamina to access and decompress nerves.         - Discectomy with Fusion: Removing the disc and fusing vertebrae with a bone graft.         - Foramenotomy: Increasing the space where nerves exit the spinal canal.

Post-Polio Syndrome ($PPS$)

• Background: Affects individuals who previously survived polio ($years$ later).

• Pathophysiology: Surviving neurons originally generated "axon sprouts" to compensate for lost neurons. As the patient ages, these sprouts become overloaded, fail, and die, leading to new weakness.

• Manifestations: Fatigue, muscle weakness, and sleep apnea.

• Management:     - Pacing activities to conserve energy.     - Pulmonary hygiene.     - Continuous Positive Airway Pressure ($CPAP$) for sleep apnea.

Questions & Discussion

• Closing: The speaker noted that while these conditions are terminal or progressive, nurses must not abandon the patient, as "patients are living until the end."

• Inquiry: The speaker invited audience members to raise their hands for any questions following the summary of the slides.