Neurologic 7% Flashcards
Raccoon Eyes
Indication of basal skull fracture involving anterior fossa
Dripping of fluid from nose or ear of patient with basal skull fracture highly suggestive of a cerebrospinal fluid (CSF) leak.
CSF Leakage
Leakage from the nose or ear canal indicates a tear in the dura.
Dural tears increase the risk of infection.
Nursing care: Provide a sterile field for the drainage, nasal packing could lead to increased intracranial pressure (ICP).
Recombinant Tissue Plasminogen Activator (rt-PA)
Fibrinolytic Agent
Must be initiated within 3 hours of onset of symptoms
Complications:
Intracranial bleeding
Seizure (suggestive of intracranial hemorrhage).
Therapeutic Hypothermia
Reduces the metabolic demand of the brain.
Most important intervention to prevent anoxic encephalopathy is the prompt restoration of cerebral oxygenation through basic life support and advanced cardiovascular life support.
This often includes hypothermia immediately afterwards.
Why keep a neurological patient’s head in neutral head position?
Keeping the head and neck in a neutral position allows optimal venous drainage through the jugular veins.
Cerebral Perfusion Pressure (CPP) = ?
CPP = mean arterial pressure (MAP) - ICP
Goal CPP of at least 60 mm Hg.
Ex. ICP is 40 mm Hg, MAP must be at least 100 mm Hg to keep CPP at least 60 mm Hg.
Increase in ICP
Positive Pressure Ventilation (increases intrathoracic pressure)
Hypoxia (leads to vasodilation
Which of the following should not be used to determine central response to pain?
- Sternal Rub
- Trapezius Squeeze
- Nailbed Pressure
- Supraorbital Pressure
Nailbed Pressure
Nailbed pressure is peripheral pain.
Can be used to determine whether the patient can feel and withdraw such as checking for paralysis
Neurologic Change Early Signs
Change in LOC is the best indicator for change in neurologic function.
Reflection of cerebral and reticular activating system functioning.
Pupil changes may be early but usually follow LOC
Changes in motor function usually are an indication of a focal lesion in one of the cerebral hemispheres.
Vital sign changes are a late sign of intracranial hypertension.
Neurologic Change Late Signs
Elevated blood pressure
Dysrhythmias (Bradycardia)
Posturing
Major Sources of Intracranial Hypertension after Craniocerebral Trauma
Cerebral Edema and Expanding Lesions (e.g. hematoma)
Computated Tomography (CT) Scan of Head
Performed initially following stroke-like symptoms to identify intracranial hemorrhage
Angiogram
Visualizes extracranial and intracranial vasculature
Would be performed if intracranial hemorrhage is identified on a CT scan
Definitively show the location and size of any aneurysmal dilation
Lumbar Puncture
Collection of cerebrospinal fluid (CSF) by lumbar puncture
Can identify if and what infective organisms are present
If organism is bacterium, CSF will be cloudy and the glucose level will be decreased.
Contraindicated in patient with clinical indications of intracranial hypertension because herniation may occur
Evoked Potentials
Evoked potential studies measure the electrical responses in brain waves in response to sensory stimuli and are not indicated.
Cerebrospinal Fluid (CSF)
Test positive for glucose
Glucose in the CSF is 60% of the glucose in the serum.
Compensation
Ability of the brain contents to be shifted to prevent intracranial hypertension when intracranial volume increases
- Cerebrospinal fluid (CSF) production decreases
- Reabsorption is increased
- CSF is shunted to the lumbar spine
- Central nervous system hypertension causes hypocapnia, alkalosis, and vasoconstriction which reduce the amount of blood in the cranium.
- Eventually part of the brain is shifted out of the cranium (i.e., herniation)
Autoregulation
Relates to the ability of the crebral vessels to change size to normalize blood flow.
Cranial Nerves V (trigeminal), VII (facial), IX (glossopharyngeal), X (vagus), and XII (hypoglossal)
Important for eating without the danger of aspiration.
Control gag and swallow response
Must be intact bilaterally to protect the patient’s airway.
Decerebrate Posturing
Abnormal extension
Arms extended and hyperpronated
Decorticate Posturing
Abnormal flexion
Arms flexed against the chest
Early Sign of Uncal Herniation
First sign is ipsilateral pupil dilation with a sluggish reaction as a result of pressure on cranial nerve III.
Motor weakness may occur but would be on the contralateral side.
Contusion can act as a mass lesion and cause a unilateral shift and uncal herniation.
A scalp laceration located over a depressed skull fracture requires what?
Immediate surgery because there is a direct route between the outside environment and the brain, increasing risk for infection.
Meningitis
Classic clinical presentation includes: Headache Stiff neck High fever Kernig sign Brudzinski sign
Decrease in ICP
Low paCO2 (hyperventilation) (causes cerebral vasoconstriction and decrease in intracranial volume) Cerebral dehydration with osmotic diuretics (mannitol) would decrease intracranial volume Sedation decreases the oxygen requirements of the brain and may contribute to maintenance of normal ICP Hypocapnia (low PaCO2) (Causes vasoconstriction which decreases intracranial volume and pressure)
Myasthenia Gravis
Disorder of voluntary muscles caused by a defect in nerve impulse transmission at the neuromuscular junction.
Causes muscle weakness and fatigability.
Autoimmune disorder with destruction of acetylcholine receptors causing interference of neuromuscular transmission leading to muscle weakness and fatigability
Cranial Nerve III
Ability of the pupil to constrict
As ICP increases, changes in pupil size and reactivity occur
Pupil on the side of the pressure will dilate and become sluggish in response to light and finally nonreactive to light
Controls the ciliary response and constriction of the pupil
Cranial Nerve II
Responsible for vision
Cranial Nerves III, IV, and VI
All involved in eye movement
Cardiac Condition Representing Greatest Risk for Ischemic Stroke
Atrial fibrillation
Most significant cardiac risk factor for ischemic stroke
Due to mural thrombi which develop in the atria and then embolize from the left atrium to the cerebrovascular system
Prevention of stroke is primary reason that patients with chronic afib are maintained on anticoagulants
Subdural Hematoma
S/S may not occur for weeks to months after trauma
Many patients cannot remember a precipitating trauma
May occur spontaneously, especially in elderly patients, alcoholics, and patients taking anticoagulants
Can be acute, subacute, or chronic
Major Complications of Subarachnoid Hemorrhage
Cerebral Vasospasm
Narrowing of the vessel lumen caused by actual constriction or inflammation
Occurs anytime from 3 days to 2 or 3 weeks after hemorrhage
Cerebral rebleeding
Peaks 24 to 48 hours after hemorrhage and again 7 to 10 days after the initial bleed
*Mortality rate is high with both complications
Subarachnoid Hemorrhage
Caused by vascular problem
Bleeding from an aneurysm, that blood irritates the meninges.
Clinical presentation not consistent with intracranial, epidural, or subdural bleeding because the blood is not in contact with the meninges in those situations
Monro-Kellie Hypothesis
Physiologic concept
If one of the three intracranial volumes goes up, one of the other two intracranial volumes will go down to prevent an increase in ICP.
About shifting of intracranial contents to prevent an increase in ICP
Abnormalities Possible With Subarachnoid Hemorrhage
Cardiac dysrhythmias (torsades de pointe, T-wave changes, and U-waves
Protein levels are low in any negative LP
Hyponatremia occurs either due to SIADH or cerebral salt wasting, without complete clarity of the cause.
No hyperkalemia
Broca Aphasia
Inability to express oneself
Motor or expressive aphasia
Caused by a problem in Broca area of the frontal lobe
Wernicke Aphasia
Inability to understand what is being communicated
Sensory or receptive aphasia
Caused by a problem in Wernicke area of the temporal lobe
Dysprosody
Lack of inflection during speech, Foreign Accent Syndrome
Dysphagia
Difficulty swallowing
Epidural Hematoma
Classically present with short period of unconsciousness followed by a lucid interval and then rapid deterioration
Usually caused by arterial bleeding
Linear Fractures Link to Epidural Hematoma
Linear fractures of the temporal bone frequently disrupt the middle meningeal artery and cause epidural hematoma
Intracerebral Hemorrhage
Usually associated with hypertension, aneurysm, or arteriovenous malformation
Amyotrophic Lateral Sclerosis (ALS)
Chronic progressively debilitating disease
Causes degeneration of the upper and lower motor neurons and muscular atrophy
Not considered hereditary disorder
No demyelination
Not caused by trauma
Transient ischemic attack (TIA)
Cerebral hypoperfusion
Reversibility within 24 hours
Stroke-like symptoms
Contusion
Bruise on the brain
Oculocephalic Reflex
Patient must be assessed for cervical spine injury prior to testing oculocephalic reflex
Doll’s eyes
Requires head to be turned side to side
Normal response is that the eyes move in the direction opposite the direction the head is turned.
Absence of doll’s eyes is when eyes stay midline or fall to the direction that the head is being turned toward.
Absence of doll’s eyes indicates brainstem injury.
Guillain-Barre Syndrome (GBS)
Acquired acute inflammatory demyelinating axonal polyneuropathy.
Affects motor more than sensory nerves.
Frequently follows a viral or bacterial illness or influenza vaccination.
Patients with GBS are admitted to the critical care unit most often for acute respiratory failure.
HOB for infratentorial craniotomy
0 degrees (flat)
Infratentorial means below the tentorium
Tentorium is a fold of the dura that separates the cerebrum from the cerebellum and the brainstem.
The head of the bed should be maintained at 0 to 20 degrees after infratentorial craniotomy to prevent pressure on the brainstem.
Battle Sign
Basal skull fracture of the middle fossa.
Bruising of the mastoid.
Basal Skull Fractures of the Posterior Fossa
Do not cause either raccoon eyes or Battle Sign
Do increase the risk of epidural hematoma and cranial nerve defects.
Cushing Triad
Cushing Reflex
Late sign of increased intracranial pressure (ICP).
Increased systolic blood pressure with a decrease in diastolic blood pressure (widened pulse pressure) and bradycardia.
Kernig Sign
Resistance to leg extension with the hip flexed.
Indicative of meningeal irritation
Uncal herniation
Uncus, located at the tip end of the medial temporal lobe, protrudes over the tentorial edge as a result of increased intracranial pressure.
Side-to-side shift
Cranial nerve III is compressed by this displacement, causing dilation and nonreactivity of that pupil.
Eventually will cause pressure on the brainstem and respiratory cessation.
Central herniation
Downward displacement that puts pressure on the reticular-activating system.
First sign is change in level of consciousness.
Eventually will cause pressure on the brainstem and respiratory cessation.
Intracranial Pressure (ICP) Waveforms
A waves
A waves: (Plateau waves)
Spontaneous, rapid increases in pressure between 50 and 200 mm Hg that last 5 min or more.
Waves cause cerebral ischemia and are most clinically significant.
Immediate intervention necessary to prevent further brain injury and herniation.
A waves are AWFUL
Intracranial Pressure (ICP) Waveforms
A waves
A waves: (Plateau waves)
Spontaneous, rapid increases in pressure between 50 and 200 mm Hg that last 5 min or more.
Waves cause cerebral ischemia and are most clinically significant.
Immediate intervention necessary to prevent further brain injury and herniation.
A waves are AWFUL
Intracranial Pressure (ICP) Waveforms
B waves
B waves are BAD
Look for and prevent causes of intracranial hypertension.
Elevation of ICP to 20 to 50 mm Hg occurring every 30 seconds to 2 min.
Intracranial Pressure (ICP) Waveforms
C waves
C waves are COOL.
Elevation of ICP to 20 to 25 mm Hg every 4 to 8 min
Rule of Truama
Everything moves until it stops.
Rule of Trauma
Everything moves until it stops.
Vasospasm
Significant cause of morbidity in patients with subarachnoid hemorrhage
Vasospasm
Significant cause of morbidity in patients with subarachnoid hemorrhage
Intracranial Pressure (ICP) Monitoring Systems Management
Continuous flush preferred to avoid small volume increases in ICP.
Heparin not added due to causing intracranial hemorrhage.
Cerebrospinal fluid does not clot.
Preservative-free saline only for priming tubing due to potential for meningeal irritation from preservatives.
Transducer leveled to the foramen of Monro. (External reference point is tragus of the ear).
Pentobarbital-Induced Coma
Ideally have ICP line inserted.
Monitor changes in ICP and calculation of cerebral perfusion pressure (CPP) as well as brain tissue oxygen monitor.
LOC cannot be assessed for patients in coma.
Pupil changes best assessment to detect neurologic changes in the earliest stage for this patient.
Pronator (Ulnar) Drift
Indicates unilateral weakness
Patient holds out arms in front and one arm drifts slightly downward.
Hemiparalysis
Prevents patient from even raising limbs when testing muscle weakness.
Hemianesthesia /Agnosia
Test for sensory findings in stroke patients
NIH Stroke Scale (NIHSS)
Questions should be asked in order.
Answers should come from the patient rather than the family.
What the patient can actually do should be recorded.
Assessment should be objective.
Effect of intracranial volume increase on intracranial pressure (ICP)
With no brain pathology, a small initial increase in intracranial volume has no effect.
Brain is normally compliant.
Injured brain is noncompliant.
increase in volume result in increased pressure.
Small increase in volume results in profound increase in ICP and resultant herniation.
Cytotoxic Cerebral Edema
Caused by hypo-osmolality or hypoxia with resultant failure of the sodium-potassium pump.
Cellular - have cellular cause
Cardiac arrest is global brain problem which would affect all cells.
Vasogenic Cerebral Edema
Increase in extracellular fluid caused by a breakdown of the blood-brain barrier with the resultant increase in vascular permeability.
Begins locally and becomes more generalized.
Common causes are trauma (including surgical trauma), tumors, hemorrhage, and abscesses.
Craniotomy for a brain tumor
Traumatic brain injury
Brain abscess secondary to sinus infection
Passive Range of Motion
Slight resistance expected when flexing and extending the limb.
Transphenoidal Hypophysectomy
Common for CSF leak from the nose to occur approximately 48 hours following procedure.
Cerebellum
Controls balance and coordination
Presence of lesion results in difficulties with …
Coordinating movement
Equilibrium
Muscle tone
Proprioception
Ex. Nystagmus, ataxia, unsteady gait, and problems with rapid, alternating movements
Pituitary Gland
Endocrine gland that controls release of hormones within the body
Brainstem
Contains cardiac and respiratory centers, temperature, and other basic drives
Respiratory centers primarily in the pons with influence from the medulla
Frontal Lobe
Controls voluntary motor function and behavior
Cerebrum
Responsible for upper level functions such as integration of thought and control of voluntary functions
Hypothalamus
Regulates body temperature, food and water intake, sleep, and endocrine function.
Electromyelogram
Detects muscle disease
Cisternogram
Shows CSF flow
ICP A Wave Interventions
Mannitol Decreases cerebral edema Hyperventilation therapy Causes cerebral vessel constriction and decrease in blood volume in the head Drainage of CSF via IVC Reduces the volume of CSF in the head
Intraventricular Catheter (IVC)
Closed system
Fever in Neurologic Conditions
Each increase in temperature of 1 C, the cerebral oxygen consumption increases 7%.
Increase in body temperature has significant adverse effect on cerebral oxygenation.
Fever would cause a shift in the oxyhemoglobin dissociation curve to the right, which impairs pickup but facilitate drop-off of oxygen at the tissue level.
To Maintain Autoregulation, CPP Must Be Maintained Above What Level?
50 mm Hg
Autoregulation is the ability of the cerebral vessels to change their size to normalize blood flow.
MAP of 60 mm Hg is required to perfuse vital organs. Normal ICP is around 10 mm Hg. CPP would be 50 mm Hg.
Hyperventilation Therapy Reserved for Indications of Acute Herniation, Why?
Resultant vasoconstriction decreases intracranial volume and pressure but causes cerebral ischemia.
Hyperventilation causes respiratory alkalosis which causes vasoconstriction, decreasing intracranial volume and pressure.
Vasoconstriction potentially causes cerebral ischemia.
Status Epilepticus Management
- Benzodiazepine (Lorazepam first choice. Diazepam may be used if lorazepam not available)
Crosses the blood-brain barrier quickly. - Phenytoin or Fosphenytoin
Used following Lorazepam - Phenobarbital
Used after benzodiazepine or phenytoin has failed.
Multiple Sclerosis (MS)
Progressive demylination of nerve fibers in the central nervous system (CNS)
Demyelinating disorder of white matter of the brain and spinal cord (CNS).
May have genetic aspect but not considered hereditary.
Concussion
Associated with focal neurologic deficit or alteration in level of consciousness that clears within 6 to 12 hours or less.
Retrograde or antegrade amnesia is common.
Med Management of Intracranial Hypertension
Diuretic (osmotic diuretic mannitol)
Mannitol
Osmotic diuretic
Administer through an in-line filter due to likely presence of unseen crystals
May crystallize out of solution if exposed to low temperatures
If crystals present, warm solution
Use filter needle when drawing up from a vial
Babinski Reflex
Indication of upper motor neuron lesion
Located in the central nervous system (brain or spinal cord)
Great toe moves upward and other toes fan out when bottom of foot is stroked.
Cranial Nerve V
Trigeminal
Motor fibers innervate the muscles of mastication
Cranial Nerve VII
Facial
Motor fibers innervate all muscles of the face
Cranial Nerve IX
Glossopharyngeal
Works with X in swallowing and the gag reflex
Cranial Nerve X
Vagus
Works with IX in swallowing and the gag reflex
Cranial Nerve XII
Hypoglossal
Innervates muscles of the tongue
HOB Elevation Goal
HOB at 30 degrees
Helps facilitate venous drainage via the jugular veins from the cerebrum.
HOB elevations of 45 degrees or greater may increase intra-abdominal pressure and increase intracranial pressure or decrease blood pressure.
