Brain Injury: Final Exam Flashcards
Define Focal Injury.
A focal traumatic injury results from direct mechanical forces (such as occur when the head strikes a windshield in a vehicle accident)
Define Global Injury.
Yielding a larger deficit from the injury. (Such as altered consciousness, coma, loss of reflexes)
What is the Reticular Activating System?
RAS is the brain stem’s reticular activation system (which is responsible for our wakefulness, and our ability to focus, fight-flight responses)
Low RAS activity means lower awareness/wakefulness
What Happens When the RAS Becomes Damaged?
Damage can cause an overall decrease in awareness and activity which will lead to:
- Decreased Perfusion
- Altered metabolic State (Metabolic acidosis)
- Altered Consciousness
Define Brain Death.
Brain death is used to define a state where there is no motor control, no response to stimuli, no brain stem reflexes and apnea when the patient is removed from the oxygen machine.
Define Vegetative State.
The brainstem functions to maintain adequate hypothalamic function to meet basic metabolic needs. However, there is no awareness of self or surroundings, and an inability to voluntarily interact and reproduce behavioural responses.
Define Cerebral Edema.
Cerebral edema is the swelling of the brain bowling a primary brain injury! Caused by an increase in fluid within the extravascular space and increased ICP.
What is the Monro- Kellie Hypothesis?
It deals with how ICP is affected by CSF, the brain’s blood, and tissue and how these structures work to maintain cerebral perfusion pressure (CPP). If the volume of one of these structures increases, the others must decrease their volume to help alleviate pressure.
What are the Main Types of Edema?
Vasogenic: this occurs when the blood-brain barrier is compromised. Mainly a result of head injury, hemorrhage OR CNS infection which leads to inflammation. The blood flow is increased in the brain which causes Edema.
Cytotoxic: Increased Intracellular fluid shift into the cells, causing an increased ICP. Extracellular Na+ and other cations enter into neurons and astrocytes and accumulate intracellularly causing fluids to accumulate.
What Happens When the Intracranial Pressure Increases?
There is limited cerebral flow, due to the decreased cerebral perfusion from the building pressure in the brain. The brain cells will be starved from oxygen, blood and nutrients causing cellular dysfunction.
What is the Normal ICP?
Normal ICP= 0- 15 mmHg
Define Cranial Perfusion Pressure (CPP).
CPP= pressure gradient between the internal carotid artery and subarachnoid veins
(this tells us how much blood pressure is required to perfuse the brain)
The minimum CPP is 45 mmHg
Signs and Symptoms of Increased ICP.
- Mental Status Changes
- Irregular breathing
- Nerve changes to the optic and oculomotor nerve: double vision, swelling of the optic nerve (papilledema), pupil changes (decreased, increased, or unequal size)
- Cushing’s Triad: Increased systolic blood pressure (widening pulse pressure: increase in SBP and decrease in DBP), decreased heart rate, and abnormal breathing
Treatment for Cerebral Edema.
- Administer hypertonic normal saline solution
- Administer Osmotic Diuretics
- Drainage of CPF (if necessary)
- Treat the cause (Administer antibiotics, reperfuse, clot lysis)
- Maintain Vitals
Define Cerebrovascular Accident.
Also known as a STROKE. When blood flow to a part of your brain is stopped either by a blockage or the rupture of a blood vessel.
Two Types of CVAs
- Thrombotic/Ischemic Stroke
- Hemorrhagic Stroke
Define Thrombotic/ Ischemic Stroke.
Caused by a thrombus (blood clot) in a blood vessel that belongs to the brain. The clot affects the tissues surrounding it by restricting oxygen supply causing the neural tissue and cells to die unless the circulation is quickly returned.
Define Hemorrhagic Stroke.
Caused by a rupture of a cerebral vessel with associated bleeding into the neural tissue. A hemorrhagic stroke is when bleeding interferes with the brain’s ability to function. Hemorrhagic strokes have a sudden onset!
Treatment for Hemorrhagic Stroke.
Osmotic Directs and Hypertonic NS
(Diuretics help remove excess fluids, hypertonic NS shifts fluids OUT of the cells)
What Factors Increase the Risk of CVAs?
- Hypertension
- Coronary Artery Disease
- Smoking
- Artherosclerosis
- Dyslipidemia
- TIA (transient ischemic attack)
What is a Transient Ischemic Attack (TIA)?
A ‘mini stroke’. TIAs result when a cerebral artery is temporarily blocked, decreasing blood flow to the brain. Although the blockage is temporary it is a warning sign to indicate that an individual is at risk for a stroke.
