WEEK 4 NERVOUS SYSTEM

Fall 2019, Patho Exam 2 Review

WEEK 4 – NERVOUS SYSTEM

• Nervous System
• What makes up the autonomic nervous system?
• The sympathetic and parasympathetic nervous systems

ii. What is the parasympathetic nervous system?

• It conserves energy and the body’s resources
• “Rest and Digest”

iii. What is the sympathetic nervous system?

• Responds to stress by preparing the body to defend itself
• “Fight or Flight”
• How does this happen (5)?
• Catecholamines released – epinephrine
• Mobilizes energy stores and increases blood glucose and

decreases release of insulin

• Redistributes blood flow and increases muscle perfusion
• Increases diameter of bronchioles in the lungs
• Decreases peristalsis of the GI tract and skin
• Primary Brain Injury
• How are primary brain injuries classified?
• Focal or diffuse
• What are focal brain injuries?
• Specific, grossly observable brain lesions that occur in a precise location

ii. Ex: epidural hemorrhage, subdural hemorrhage

• What are diffuse brain injuries?
• Also called multifocal injuries

ii. Includes brain injuries due to hypoxia, meningitis, encephalitis, and damage to blood vessels

• What effect does swelling have after a traumatic brain injury (TBI)?
• Can lead to dangerous increases in intracranial pressure

ii. REMEMBER: the brain is within a limited space, and increased pressure can

cause collateral dysfunction

1. Ex: neurogenic diabetes insipidus – ADH not secreted thus polyuria

• Autonomic Hyperreflexia
• Who is most likely affected by autonomic hyperreflexia?
• Patients that have lesions at the T5-6 level or above
• What is autonomic hyperreflexia characterized by (7)?
• Paroxysmal hypertension (up to 300mm Hg systolic)

ii. Pounding headache iii. Blurred vision iv. Sweating above the lesion level with flushing of skin

• Why does this occur?
• The hypothalamus is unable to regulate body heat because of

sympathetic nervous system damage

• Piloerection

vi. Nasal congestion vii. Bradycardia (30-40bpm)

• Delirium and Dementia
• Delirium

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• What age does delirium occur?
• Usually older

ii. What is the onset?

• Acute – most common during hospitalizations

iii. Are there any associated conditions (9)?

1. UTI

• Thyroid disorders
• Hypoxia
• Hypoglycemia
• Toxicity
• Fluid-electrolyte imbalance
• Renal insufficiency
• Trauma
• Multiple medications

iv. What is the course?

• Fluctuating; remits with treatment
• What is the duration?
• Hours to weeks

vi. How is the patient’s attention?

• Impaired

vii. How is their sleep-wake cycle?

• Disrupted

viii. How is their alertness and orientation?

• Impaired

ix. What is their behavior like?

• Agitated, withdrawn/depressed
• What is their speech like?
• Incoherent
• Can be rapid or slowed

xi. What are their thoughts like?

• Disorganized with delusions

xii. What are their perceptions like?

• Hallucinations/illusions
• Dementia
• What age does dementia occur?
• Usually older

ii. What is the onset?

• Usually insidious
• Acute in some cases of strokes/trauma

iii. Are there any associated conditions (9)?

• May have no other conditions
• Brain trauma

iv. What is the course?

• Chronic slow decline
• What is the duration?
• Months to years

vi. How is the patient’s attention?

• Intact early

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• Often impaired late

vii. How is their sleep-wake cycle?

• Usually normal or fragmented

viii. How is their alertness?

• Normal

ix. How is their orientation?

• Intact early
• Impaired late
• What is their behavior like?
• Intact early

xi. What is their speech like?

• Word-finding problems

xii. What are their thoughts like?

• impoverished

xiii. What are their perceptions like?

• Usually intact early
• Alzheimer’s Disease
• What is Alzheimer’s Disease
• The leading cause of dementia

ii. One of the most common causes of severe cognitive dysfunction in older adults iii. Late onset causes about 90%

• What are risk factors of Alzheimer’s?
• Greatest risk factors are age and family history

ii. Other risk factors: diabetes, hypertension, hyperlipidemia, obesity, smoking, depression, cognitive inactivity or low education attainment, female gender, estrogen deficit at the time of menopause, physical inactivity, head trauma, elevated serum homocysteine and cholesterol levels, oxidative stress, and neuroinflammation

• What is the cause of AD?
• Exact cause is unknown and no real understanding of disease process

ii. Early onset familial AD is autosomal dominant

• What gene defects are linked to AD (3)?
• Amyloid precursor protein (APP) on chromosome 21
• Presenilin 1 (PSEN1) on chromosome 14
• PSEN2 on chromosome
• How is AD diagnosed?
• FIRST, rule out ALL other causes of dementia
• Stroke
• What is the incidence of stroke?
• Two times higher in blacks than whites

ii. Tends to run in families

• What is the most common type or stroke?
• Ischemic – thrombotic or embolic
• What is the diagnostic cause?
• No identifiable cause established by conventional diagnostics

and are classified as “undetermined” or “cryptogenic”

• What are possible outcomes of stroke?
• The mildest outcome can be almost unnoticed

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ii. The most severe outcomes include hemiplegia, coma, and death

• How are strokes classified?
• According to pathology
• Ischemic – thrombotic or embolic
• Global hypoperfusion – as in shock
• Intracerebral hemorrhage
• What is the most commonly involved artery?
• Middle cerebral artery
• What is the single greatest risk factor for stroke?
• Uncontrolled hypertension
• What are other risk factors for stroke (13)?
• Insulin resistance and diabetes mellitus

ii. High total cholesterol or low high-density lipoprotein (HDL) cholesterol level, elevated lipoprotein-A level iii. Hyperhomocysteinemia iv. Congestive heart disease and peripheral vascular disease

• Asymptomatic carotid stenosis

vi. Polycythemia and thrombocytopenia vii. Atrial fibrillation viii. Postmenopausal hormone therapy ix. High sodium intake, low potassium intake

• Smoking

xi. Physical inactivity xii. Obesity xiii. Chronic sleep deprivation

• Guillain-Barre Syndrome (GBS)
• What is GBS?
• An autoimmune disease triggered by a preceding bacterial or viral infection
• What are first manifestations?
• Numbness, pain, paresthesias, or weakness in the limbs
• How do motor signs manifest?
• As an acute or subacute progressive paralysis

ii. Proximal muscles may be involved earlier and more significantly than distal muscles iii. Paresis/paralysis may be present in an ascending pattern involving limbs, respiratory muscles, and bulbar muscles

• How does weakness progress?
• Usually plateaus or improves by the 4

th week in 90% of cases

• After plateau, strength improves over a period of days to months, with

the majority reaching levels similar to their pre-disease state ii. Respiratory weakness leads to need for ventilator support in 10-30% of cases iii. Cranial nerve weakness manifests as facial weakness and bulbar weakness in chewing, swallowing, and coughing

• Multiple Sclerosis
• What is MS?
• A chronic inflammatory disease involving degeneration of CAN myelin, scarring

or formation of plaque, and loss of axons