Chapter 44: Acute Disorders of Brain Function Flashcards Preview

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Flashcards in Chapter 44: Acute Disorders of Brain Function Deck (15):
1

Glasgow Coma Scale

- 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 (

2

Pupil Reflex

- Indicates the function of the brainstem and cranial nerves (CN) II and III

- Changes in size, shape, and reactivity of the pupil early indicator of ICP and possible brain herniation

- Eye movements controlled by CN III, IV, and VI may be impaired with increased ICP

- Nystagmus, dysconjugate movement, and ocular palsies may be present

3

Oculovestibular Reflex

- Impaired reflex implies brainstem dysfunction

- Doll’s-eyes maneuver entails rotating the patient’s head from side to side (Normally eyes turn in opposite direction of the head rotation)

- Cold calorics: inject cold water into ear (Normal response: tonic deviation of both eyes toward the side that is irrigated)

- Both tests have many contraindications


4

Corneal Reflex

- Wisp of cotton touches cornea of the eye to elicit a blink response

- Absence of blink response: indictor of severely impaired brain function

5

Epidemiology of Cerebrovascular disease and stroke

- Cause abnormalities of cerebral perfusion (Transient ischemic attacks (TIA), ischemic stroke, and hemorrhagic stroke)

- Stroke is a sudden onset of neurologic dysfunction due to cardiovascular disease that results in an area of brain infarction

- Stroke is the third leading cause of death in the United States

- Most common form of stroke is ischemic

- Females affected more often than males

- Risk factors are similar to those for other atherosclerotic vascular diseases (hypertension, DM, hyperlipidemia, smoking, advancing age, family history)

6

Ischemic stroke

- Results from sudden occlusion of cerebral artery secondary to thrombus formation or emboli

- Thrombotic strokes associated with atherosclerosis and coagulopathies

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

7

Clinical Manifestations and Treatment of Ischemic Stroke

- Clinical manifestations include contralateral hemiplegia, hemisensory loss, and contralateral visual field blindness

- treatment: salvaging the penumbra is the aim of early thrombotic therapy; however, treatment must be instituted within 3 hours of symptom onset to be maximally effective

8

Transient Ischemic Attack (TIA)

- Neurologic symptoms typically last only minutes, but they may last as long as 24 hours

- Symptoms resolve completely without evidence of neurologic dysfunction

- TIAs are important warning signs of thrombotic disease and carry a significant risk for subsequent stroke

- Treatment: daily aspirin; carotid endarterectomy or angioplasty if 70% occluded

9

Hemorrhagic Stroke

- Hemorrhage within the brain parenchyma

-Usually occurs secondary to severe, chronic hypertension

- Most occur in basal ganglia or thalamus

- Degree of secondary injury and associated morbidity and mortality is much higher in hemorrhagic stroke than ischemic stroke

10

Treatment of Stroke

- Cardiovascular stabilization

- Brain CT determines type and location

- ICP monitoring and management

- Ischemic stroke: treatment aimed at minimizing infarct size and preserving neurologic function (Thrombolytics, anticoagulant, antiplatelet, endarterectomy, angioplasty, stents)

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


11

Stroke: Motor Deficits

- Initially motor deficits occur as flaccidity or paralysis; recovery of motor function occurs with onset of spasticity

- Contralateral to the side of the brain where the stroke occurred

- Active/passive range of motion exercises should be started in acute phase of recovery

- Elevate edematous limbs, use elastic stockings, and maintain body alignment

- Aggressive rehabilitation commonly required

12

Stroke: Sensory Deficits

- Sensory disturbances occur in same locations as motor paralysis and may involve neglect or visual impairment

- Loss of visual field on the paralyzed side also contributes to neglect

- Contralateral field blindness: homonymous hemianopsia, the same side of the retina in each eye is blinded

- Assess fall risk

13

Stroke: Language Deficits

- Aphasia occurs with brain damage to the dominant cerebral hemisphere and can involve all language modalities

- Broca aphasia (verbal motor/expressive) consists of poor articulation and sparse vocabulary

- Wernicke aphasia (sensory, acoustic, receptive) characterized by impaired auditory comprehension and speech that is fluent but does not make sense

14

Stroke: Cognitive Deficits

- Area of brain affected dictates presence and severity of cognitive impairments

- Evidenced as language impairment, impaired spatial relationship skills and short-term memory, and poor judgment

- Concentration, memory, and reasoning may be impaired

- May require rehabilitative services

15

Meningitis

- Bacteria usually reach the CNS via the bloodstream or extension from cranial structures like sinuses or ears

- Most common bacteria are Streptococcus pneumoniae

- Bacteria invade leptomeninges; accumulation of inflammatory exudate can result in obstructive hydrocephalus

- Clinical manifestations: Headache, fever, nuchal rigidity, photosensitivity

- Tx: Depends on the organism causing infection