Neuro Flashcards
What is the most potent agent that influences cerebral blood flow?
Carbon dioxide, Cerebral vessels dilate in response to CO2 levels greater than 45 mm Hg
GCS is a measure of?
consciousness and cognition and does not replace neurological assessment of specific brain function
GCS of 8 or less is consistent with?
Coma
What conditions limit the application of the GCS?
Medication, concurrent injuries-such as spinal cord injury
What is expressive dysphasia?
a deficit in language output or speech production from a dysfunction in the dominant frontal lobe. It varies from mild word-finding difficulty to complete loss of both verbal and written communication skills
What is receptive dysphasia?
The inability to comprehend language and follow commands
How can we assess short-term memory?
ask the patient to recall the names of three common words or objects (e.g., chair, clock, blue) after a 3-minute interval
How can we assess long-term memory?
by asking the patient questions about the distant past (e.g., birthplace, year of birth, year of graduation from school, year of marriage)
What is the most critical component of cranial nerve assessment?
Pupil examination… Normal pupil diameter ranges from 1.5 to 6 mm. Pupils are often assessed hourly for size, shape, equality, and direct and consensual response to light. Remember- Hypoxia and medications may also influence pupillary size and reactivity to light.
When do we use “arm drift”?
In a conscious patient, check for arm drift to detect subtle weakness. Ask the patient to close the eyes and stretch out the arms with palms up for 20 to 30 seconds. A downward drift of the arm or pronation of the palm indicates subtle weakness in the involved extremity
What is Flexor posturing?
involves rigid flexion and adduction of the arms, wrist flexion with clenched fists, and extension and internal rotation of the legs. It usually occurs secondary to damage of the corticospinal tract (also called decorticate).
What is Extensor posturing?
the result of a midbrain or pons lesion. In this posture, the arms and legs are rigidly extended, and the feet are in plantar extension (also called decerebrate)
What are some pathological reflexes that may reappear as a consequence of impaired neuro function?
Babinski reflex, the suck (sucking motions in response to touch the lips), snout (lip pursing in response to touching the lips), palmar (grasp in response to stroking the palm), and palmomental (contraction of the facial muscle in response to stimulation of the thenar eminence near the thumb) reflexes in adults
What causes increased intracranial pressure?
results when there is an increase of one of the three components comprising ICP: brain volume, blood, or CSF fluid. Normal range is 0-15mm Hg
When can herniation result?
When ICP is sustained at a pressure of 20 mm Hg for 5 minutes or longer, herniation may result
What can cause an increase in cerebral blood volume?
Loss of autoregulation, which provides a constant blood volume and cerebral perfusion pressure over a wide range of mean arterial pressures, can occur with head injury
What are some differences in a fluid-filled transducer system (used for Intracranial Pressure monitoring)?
(1) normal saline solution without preservatives must be used so as not to damage brain tissue, and (2) the flush system is not pressurized so that there is no possibility of flushing into the cranium
What is the priority management of a patient with increased intracranial pressure?
ensuring a patent airway. In addition to ensuring a patent airway, oxygenation must be supported. Previous practice of hyperventilation to decrease carbon dioxide, reducing the vasodilatory effect on cerebral blood vessels, has been abandoned because of the potential for ischemia
What kind of meds do we see given for increased intracranial pressure?
Osmotic and loop diuretics act to reduce brain tissue volume. Osmotic diuretics draw water from the extracellular space to decrease ICP. This effect occurs within minutes of administration. Loop diuretics remove sodium and water from injured brain cells. To sustain adequate cerebral perfusion pressure, fluid administration, guided by hemodynamic monitoring, must be optimized with the appropriate fluids. Sedation: Benzos, propofol, analgesics… induced hypothermia (Goal-34-35C), seizure prophylaxis, neuromuscular blockades
What is the blood pressure management for those with Increased ICP?
To maintain MAP 70-90mm Hg, CPP of at least 70 mm Hg, avoid hypertension (usually give Nicardipine) and avoid hypotension (give vasopressors)
What structures are included in a TBI usually?
injury can result in damage to the scalp, skull, meninges, and brain. An open injury involves a tear to the scalp or a fracture that extends into the sinuses. A closed traumatic brain injury occurs when there is no break in the scalp
Primary brain injury vs secondary brain injury:
Primary brain injury is direct injury to the brain tissue. As the brain is injured, it can sustain injury to the area under the direct impact (coup) as well as distal to the site of impact (contrecoup). Secondary brain injury occurs as a result of initial trauma and is characterized by cellular changes leading to vasogenic cerebral edema
Why is early recognition of a stroke needed?
to preserve blood flow to the brain and potentially reduce disability
What are the types of strokes?
Ischemic and Hemorrhagic. Types of hemorrhagic: intraparenchymal (uncontrolled hypertension), ruptured cerebral aneurysm (dilated cerebral artery that ruptures), arteriovenous malformation (congenital abnormality)
What are some tools used to assess an acute stroke?
History (time of onset of symptoms), neuro exam (mental status, cranial nerve function, motor strength, sensory function, neglect, coordination), NIH stroke scale; ABCs