Types of Strokes

• Ischemic:

  • Caused by cerebral thrombosis, which occurs as a result of: astherosclerotic plaques, extrinsic pressure from a mass within the brain itself
  • Most common (80-85%)
  • Usually associated with a long history of vessel disease
  • S&S: are slow to develop -
  • Hemiparesis (one-sided weakness) or hemiplegia (one-sided paralysis) on opposite side of the lesion
  • Numbness on opposite side of the lesion or of face
  • Aphasia (unable to speak/understand)
  • Confusion/coma
  • Convulsions
  • Incontinence
  • Diplopia (double vision)
  • Headache
  • Dysarthria (slurred speech)
  • Dizziness or vertigo
• Cerebral Embolus:

  • Stroke caused by embolus from occlusion of any intracranial vessel by a fragment of foreign substance outside of CNS
  • Sources of cerebral emboli:
  • Atherosclerotic plaques (from head, neck, or heart)
  • Thrombi developed on valves or in chambers of heart (valvular heart disease or atrial fib)
  • Air embolism after thoracic injury
  • Fat embolism after bone injury
  • Bacterial & fungal endocarditis
  • S&S: develop more quickly, similar to thrombotic stroke
• Hemorrhagic Stroke: happens anywhere within cranial vault - epidural, subdural, subarachnoid, intrapaarenchymal, & intraventicular spaces

  • Causes: cerebral aneurysms, arteriovenous (AV) malformations, HTN
  • Often asymptomatic until time of rupture - happen during stress/exertion
  • Cocaine & other sympathomimetic amines can contribute to intracranial hemorrhage by inc. BP
  • S&S: sudden
  • Starts with HA
  • N/V
  • Progressive deterioration in mental status
  • At time of hemorrhage: LOC, seizures
  • As hemorrhage progresses: ICP increases, pt becomes comatose, Cushing reflex
• Cushing's Reflex:

  • Inc. hypertension
  • Bradycardia
  • Dec./Irregular respirations
• Transient Ischemic Attacks (TIA)

  • Episodes of focal cerebral dysfunction last from minutes to several hours then pt returns to normal in 24hrs with no permanent neurological deficit
  • Indicate impending stroke
  • S&S:
  • Weakness
  • Paralysis
  • Numbness of face
  • Speech disturbances
• Assessment:

  • Maintain patent airway
  • Give ventilations with O2
  • Obtain history
• History:

  • Previous neurological symptoms (TIA) or deficits
  • Initial symptoms & progression
  • Alterations in LOC
  • Precipitating factors
  • Dizziness, Plapitations
  • HTN
  • Cigarette smoking
  • Diabetes mellitus
  • Cardiac, sickle cell disease
  • Previous stroke
  • Oral contraceptive use
• Management:

  • Time in field must be minimized
  • Less than 3hrs from symptom onset is required for thrombolytic therapy
  • Manage pt airway, breathing, circulation
  • IV with lasted ringer solution or NS at 30mL/hr
  • Glucose - administer D50 if needed
• Airway: paralysis of muscles of throat, tongue, & mouth can lead to obstructive airway & frequent suctioning is needed
• Breathing: inadequate ventilation should be managed w/ O2 & positive pressure ventilation; respiratory arrest from severe coma-producing brain injuries should be managed w/ intubations & ventilations
• Circulation:

  • Cardiac arrest uncommon, but can follow respiratory arrest
  • Cardiac dysrhythmias are frequent
  • Monitor BP & ECG
  • Tx of HTN is not recommended
  • If condition permits - keep pt supine with head elevated 15