Disorders of the CNS

The Nervous System

  • Divided into two parts:
      - Central Nervous System (CNS):
        - Composed of the brain and spinal cord.

Functions of the CNS

  • Processes incoming information and controls the body’s response to that information.

  • Main centers where integration and coordination of nervous system information occur.

Cognitive and Motor Functions Associated with the CNS

  • Language:
      - Sequence and perform movements.
      - Understand language.
      - Produce written and spoken language.

  • Analytical Functions:
      - Controlled, logical, and rational thinking.
      - Mathematical calculations.

  • Emotional Expression:
      - Express positive emotions such as love and happiness.
      - Express negative emotions.

  • Nonverbal Processing:
      - Process information holistically.
      - Artistic abilities, general concept comprehension, hand-eye coordination, spatial awareness, and postural abilities.

  • Sensory Processing:
      - Kinesthetic awareness:
        - Understand music
        - Understand nonverbal communication
        - Mathematical reasoning

Recap of the Lobes of the Brain

  • Frontal Lobe:
      - Functions:
        - Voluntary movement, intellect, orientation, personality, temper, judgment, reasoning, behavior.
        - Broca’s area: speech, concentration.

  • Parietal Lobe:
      - Associated with sensation of:
        - Touch, pressure, vibration, pain, temperature, and taste.
        - Receives information from other brain areas regarding hearing, vision, motor, sensory, and memory.
        - Interprets language and words.

  • Temporal Lobe:
      - Primary auditory processing.
      - Wernicke’s area: ability to understand and produce meaningful speech, verbal and general memory, assists with understanding of language.

  • Occipital Lobe:
      - Main processing center for visual information:
        - Processes colors, light, and shapes.
        - Judgment of distance.

Levels of Consciousness

  • Arousal:
      - Alertness.

  • Hyperarousal:
      - Excessive responsiveness to sensory stimulation.

  • Stupor:
      - General unresponsiveness with arousal from repeated stimuli.

  • Coma:
      - Unresponsiveness to all internal and external stimuli.

  • Delirium:
      - Characterized by disorientation, confusion, agitation, and loudness.

  • Hallucinations:
      - Sensing things that are not tangibly real:
          - Can be visual, auditory, or tactile.

Memory Deficits

  • Types of Memory:
      - Short-term memory.
      - Long-term memory.
      - Amnesia: includes anterograde amnesia, retrograde amnesia, posttraumatic amnesia.

Aphasia vs. Dysarthria

  • Aphasia:
      - The inability to communicate or comprehend due to damage to specific areas of the brain.
      - Types:
        - Expressive Aphasia (Broca’s aphasia): Non-fluent speech.
        - Receptive Aphasia (Wernicke’s aphasia): Fluent speech but lacks meaning.
        - Global Aphasia: Combination of expressive and receptive deficits.

  • Dysarthria:
      - Slurred and impaired speech due to motor deficits of the tongue or other essential muscles for speech.

Definitions of Other Cognitive and Motor Disorders

  • Alexia: Inability to read.

  • Agraphia: Inability to write.

  • Apraxia: Inability to perform skilled, purposeful movements or activities.
      - Ideomotor apraxia: inability to perform actions on command.
      - Ideational apraxia: inability to perform sequences of events or tasks.

  • Agnosia: Inability to interpret information accurately (visual, auditory, etc.).

  • Ataxia: Inability to perform coordinated movements.

  • Dysmetria: Inability to judge distance or range of a movement, often associated with occipital lobe dysfunction.

  • Dysdiadochokinesia: Inability to perform rapid alternating movements, often associated with cerebellar dysfunction.

  • Nystagmus: Involuntary rhythmic or oscillatory movements of the eyes in any direction.

  • Asthenia: Generalized muscle weakness.

Conditions Affecting the CNS

Infectious Disorders of the CNS

  • Types include:
      - Meningitis
      - Encephalitis
      - Tumor

Meningitis

  • Definition: Inflammation of the meninges of the brain and spinal cord.

  • Pathophysiology:
      - Inflammation and congestion may produce thrombosis, scarring, and can restrict flow of cerebrospinal fluid (CSF).
      - Possible outcomes include hydrocephalus or subarachnoid cysts.

  • Most common form: viral meningitis.

  • Most severe form: bacterial meningitis.

  • Incidence: Approximately 3000 new cases in the US each year.

Pathogenesis of Meningitis

  • Infectious agents penetrate the blood-brain barrier and move into the CSF and the tissues of the brain.

  • During infection and inflammation, the level of leukocytes in the brain increases, responding to viral and bacterial infections.

Types of Meningitis and Causes

  • Viral Meningitis:
      - Most common cause of inflammation of the CNS.
      - Causes include:
        - Enterovirus (most common)
        - Herpes simplex virus 2
        - Epstein-Barr virus
        - Systemic lupus erythematosus (SLE)
        - Mumps and measles.

  • Tuberculous Meningitis:
      - Caused by Mycobacterium tuberculosis.

  • Bacterial Meningitis:
      - Most severe form.
      - Causes include:
        - Haemophilus influenzae type b (HIB)
        - Streptococcus pneumoniae
        - Neisseria meningitidis.

  • Vaccinations recommended for prevention:
      - HIB, pneumococcal, meningococcal, and MMR vaccines.

Signs & Symptoms of Meningitis

  • Headache.

  • Stiff and painful neck.

  • Fever, vomiting.

  • Pain in lumbar area and posterior aspects of the thighs.

  • Positive Kernig’s sign and Brudzinski’s sign.

  • Seizures, coma, rash.

Diagnosis of Meningitis

  • Lumbar Puncture (Spinal Tap): key diagnostic tool.

  • Imaging Tests:
      - X-rays to rule out bone fractures.
      - CT or MRI scans for visualization of the meninges and brain.

  • Lab Testing for identification of infectious agents.

Medical Management of Meningitis

  • Treatment:
      - Begin immediately if meningitis is suspected.
      - Antibiotic therapy (for bacterial meningitis).
      - Antiviral therapy (for viral meningitis).

  • Criteria for Outpatient Management:
      - Inpatient microbial therapy for six or more days.
      - No fever for at least 24 to 48 hours.
      - No significant neurologic dysfunction.
      - Stable or improving condition.

  • Prognosis: Mortality varies from 5% to 25%, primarily associated with bacterial meningitis.

Precautions for Meningitis

  • Contact Precautions:
      - Gown & gloves.

  • Droplet Precautions:
      - Surgical mask.

  • Airborne Precautions:
      - N95 mask for:
        - Herpes simplex virus 2, Enterovirus, Measles, Epstein-Barr, Mumps, Mycobacterium tuberculosis, HIB, Streptococcus pneumoniae, Neisseria meningitidis.

Encephalitis

  • Definition: Acute inflammatory disease of the brain tissue.
      - Caused by direct viral invasion or hypersensitivity initiated by a virus.
      - Characterized by inflammation primarily in the gray matter of the CNS.

  • Most cases globally are caused by viruses transmitted by mosquitoes or ticks (vectors).

Causes of Encephalitis

  • 2/3 of cases of viral encephalitis have unidentified causes.

  • Infectious Encephalitis:
      - Vector-borne (mosquito or tick transmitted).

  • Autoimmune Encephalitis:
      - Medicated by the immune response.

  • Vaccine-preventable Encephalitis:
      - MMR and Varicella vaccinations.

  • Herpes Simplex Virus 1 & 2:
      - Causes cold sores and genital herpes, known for causing encephalitis.

  • Epstein-Barr Virus:
      - Associated with mononucleosis.

Pathogenesis of Encephalitis

  • Encephalitis elicits an inflammatory response, resulting in:
      - Swelling of infected cells and degeneration of cellular nuclei, leading to cell death.
      - Destruction of plasma membranes.
      - Damage to oligodendrocytes, potentially creating scarring.

Signs & Symptoms of Encephalitis

  • Headache.

  • Nausea and vomiting.

  • Altered consciousness and coma.

  • Agitation, stiffness of the back and neck.

  • Seizures, hallucinations.

  • Disturbance of memory, fatigue,

  • Fever, skin rash, diarrhea.

  • Diminished deep tendon reflexes.

Medical Management of Encephalitis

  • Diagnosis:
      - MRI, Lumbar Puncture (LP), blood tests.

  • Treatment Varies by Infectious Agent:
      - Bed rest, fluids, NSAIDs for symptom relief.
      - Antiviral/antibiotic medications as needed.
      - Physical therapy focused on balance, strength, and coordination, depending on the effects on the patient.

Tumors

  • Definition: Tumors may develop in the brain, spinal cord, or surrounding structures.

  • Tumors can be:
      - Benign vs. Malignant.
      - Primary vs. Secondary: Primary cancer types that may metastasize to the brain include breast, colon, kidney, lung, and melanoma.

Pathogenesis of Tumors

  • Tumors may displace or push spinal cord or brain tissue, block CSF flow, and compress surrounding tissue.

  • Types of tumors can invade and destroy normal brain tissue while causing increased intracranial pressure by pressing on normal tissue.

Signs & Symptoms of Tumors

  • Headache (HA).

  • Seizures.

  • Blindness and paralysis/numbness/tingling.

  • Cognitive impairments, difficulty with balance.

  • Speech difficulties, personality changes, or behavior changes.

Diagnosis of Tumors

  • Neurological Exam: To assess cognitive and physical function.

  • Imaging Tests:
      - MRI, CT scans, PET scans with dye to visualize cancerous cells.

  • Biopsy: Needle inserted into tumor to remove tissue sample for histopathological examination.

Treatment for Tumors

  • Options Include:
      - Surgery to remove tumor.
      - Radiation therapy to target malignant cells.
      - Chemotherapy to kill cancerous cells.
      - Rehabilitation therapies (PT, OT, ST) for restoring function affected by the tumor.
      - Alternative therapies like meditation and hypnosis, along with support group therapy.

Prognosis of Tumors

  • Prognosis varies based on:
      - Type of brain tumor.
      - Tumor size, grade, and location.
      - Benign vs. malignant classification.
      - Patient's age and overall health.
      - Length of time experiencing symptoms.
      - Types of treatments employed.

References

  • Cavallaro Goodman, C., & Fuller, K. S. (2017). Pathology for the Physical Therapist Assistant (2nd ed.). St. Louis, MO: Elsevier.

  • Giles, S. M. (2020). PTAEXAM: The complete study guide. Scarborough, ME: Scorebuilders.

  • John Hopkins Medicine. (n.d.). Brain tumors and brain cancer. Retrieved from https://www.hopkinsmedicine.org/health/conditions-and-diseases/brain-tumor#locations

  • Mayo Clinic Staff. (2024). Brain tumor. Retrieved from https://www.mayoclinic.org/diseases-conditions/brain-tumor/symptoms-causes/syc-20350084

  • O’Sullivan, S.B. & Schmitz, T. (2014). Physical rehabilitation (6th ed.). Philadelphia, PA. F. A. Davis.

  • Tortora, G. J., & Derrickson, B. (2009). Nervous tissue and the spinal cord and spinal nerves. In Principles of anatomy and physiology (12th ed., pp. 415–490). Wiley.

Images

  • For additional information, refer to these links:
      - https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-most-common-brain-tumor-5-things-you-should-know
      - https://medicine.washu.edu/news/aggressive-brain-tumor-mapped-in-genetic-molecular-detail/
      - https://www.2minutemedicine.com/patient-basics-brain-tumor-overview/
      - https://drprofyris.com/brain-tumour-resection/
      - https://blog.rapidwristbands.com/support-gray-the-brain-tumor-symbol
      - https://www.mayoclinic.org/diseases-conditions/encephalitis/symptoms-causes/syc-20356136
      - https://www.narayanahealth.org/blog/meningitis-in-children-causes-symptoms-and-treatment-options
      - https://my.clevelandclinic.org/health/diagnostics/12544-lumbar-puncture-spinal-tap