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Respiratory system includes: Nose and nasal cavity, Pharynx, larynx, trachea, Bronchi and their smaller

branches, Lungs and the air sacs called alveoli,

Hypoxemia - deficient oxygen in bloodstream / Hypoxia - a decrease in tissue oxygenation

Hypercapnia – excessive carbon dioxide levels in blood / Dyspnea – shortness of breath

Tachypnea – rapid respirations, >20 breaths per minute

1. Review the difference between primary and secondary brain injury

 Primary brain injury - occurs as a direct result of the initial insult

Example – Stroke, concussion

 Secondary injury - refers to progressive damage resulting from the body’s physiologic response

to the initial insult

Example – brain swelling secondary to stroke

 Critical factor in determining the neuronal cell fate after injury - degree of adenosine

triphosphate (ATP) depletion

2. Review causes of intracranial pressure; how does it lead to impaired neurological function?

Increased Intracranial Pressure (ICP)

 Volume of cranium composed of three elements:

o Brain tissue

o Cerebrospinal fluid (CSF)

o Blood

 Normal ICP 0 to 15 mm Hg

 Increased ICP can occur with space-occupying lesions, edema, or with obstruction or excessive

Increased Intracranial Pressure (ICP)

 Leads to impaired neurological functions due to:

 Compression of brain tissue

 Inability of the cranium to expand in adults – bones of skull fused in adulthood

 Reduced blood flow to the brain from increased pressure

 production of CSF

3. What are signs of increased ICP?

 Clinical manifestations

o Headache, vomiting, and altered level of consciousness (drowsiness)

o Blurry vision

o Pupil responsiveness to light becomes impaired

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o Altered respiratory patterns and unresponsive to stimulation

o Patient may become unable to move, verbalize, or open the eyes

4. Review the Glasgow coma scale, what is it used to assess?

Standardized tool for assessing LOC in acutely brain-injured persons

Numeric scores given to arousal-directed responses of eye opening, verbal utterances, and motor

reactions

Mild (>12), moderate (9 to 12), to severe (<8)

Motor response is the most powerful predictor of patient outcome

Decorticate posturing, abnormal flexor

Decerebrate posturing, abnormal extension

Traumatic brain injury (TBI) leading cause of death and disability in United States

 Most head injuries incurred in transportation-related accidents, falls, firearms, and sports

accidents

 Severity of TBI is classified by the Glasgow coma scale (GCS) as:

 Mild - GCS score 13 to 15

 Moderate - GCS score 9 to 12

 Severe - GCS score 8 or below

 Primary injury

 Usually caused by a sudden and violent blow or jolt to the head (closed injury) or a penetrating

(open injury) head wound that disrupts the normal brain function

 The injury can bruise the brain, damage nerve fibers, and cause hemorrhaging

 Secondary Injury

 Body’s response to initial injury may cause more harm than the initial injury

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 Can cause ischemia, hypoxic events, vasogenic/neurogenic edema, and other processes that lead to

brain swelling and increased ICP

 Ruptured vessels may rebleed or spasm, and CSF drainage can become clogged

5. Review the different types of stroke: ischemic versus hemorrhagic. How is a stroke diagnosed?

 Ischemia and Hypoxia

 Ischemia = decreased blood flow

o Ischemia results in immediate neurologic dysfunction because of inability of neurons to

generate ATP needed for energy-requiring processes

 Hypoxia = decreased oxygen at cellular level

 Usually ischemia and hypoxia occur together ****

o Stroke is a sudden onset of neurologic dysfunction caused by cardiovascular disease that results in an

area of brain infarction

o Transient ischemic attacks (TIA)

o Ischemic stroke

o Hemorrhagic stroke

Stroke is the fifth leading cause of death in the U.S.

Most common form of stroke is ischemic

Risk factors include:

 Hypertension

 DM

 Hyperlipidemia

 Smoking

 Advancing age

 Family history

 Results from sudden blockage (occlusion) of cerebral artery secondary to thrombus formation

or emboli

 Thrombotic strokes associated with atherosclerosis and clotting disorders (coagulopathies)

 Embolic strokes associated with cardiac dysfunction or dysrhythmias (atrial fibrillation)

Clinical manifestations Ischemic stroke

 Contralateral paralysis on one side of the body (hemiplegia)

 Facial dropping, ptosis

 Hemisensory loss

 Contralateral visual field blindness

 Difficulty with speech (aphasia)

Hemorrhagic Stroke

o Result of a bleed within the brain

o Less common compared to ischemic stroke

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o Usually occurs secondary to severe, chronic hypertension

o Can also be the result of severe head trauma, an aneurysm, or an arteriovenous malformation (AVM)

o Anticoagulant use puts an individual more at risk for hemorrhagic stroke

HOW IS STROKE DIAGNOSED?

Brain CT determines type and location

o Cardiovascular stabilization

o ICP monitoring and management

o Ischemic stroke - treatment aimed at minimizing infarct size and preserving neurologic function

o Thrombolytics, anticoagulant, antiplatelet, endarterectomy, angioplasty, stents

o Hemorrhagic stroke - blood pressure management (keep patient mildly hypertensive at first)

6. Review the difference between meningitis versus encephalitis

Meningitis - Inflammation of the meninges of the brain

 Can be due to bacterial, viral or fungal infections

 Most common causes: Streptococcus pneumoniae (pneumoncoccus), Neisseria meningitidis

(meningococcus), Haemophilus influenzae

 Bacteria usually reach the CNS via the bloodstream from sinuses or ears

 Most cases of viral meningitis due to Enteroviruses

 Other viruses include herpes virus, West Nile virus, mumps, HIV

Classic presentations - headache, fever, stiff neck (nuchal rigidity), photophobia, “splotchy” purple rash,

confusion, delirium

Diagnosis - lumbar puncture

Treatment - intravenous antibiotic therapy for bacterial, supportive measures for viral, corticosteroids

Prevention - vaccinations for Hib and N. meningitidis

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