Disorders of Brain Function Flashcards
How do brain injuries occur?
Ischemia Trauma Tumors Degenerative processes Metabolic Derangements
Hypoxia and Ischemic Injury
Hypoxia
- low O2
- interferes with delivery of oxygen to the brain
- Ischemia
Low Blood Flow (think systematic)
- interferes with delivery of oxygen and glucose along with removal of waste products
- ex: hypovolemic shock, profusion issue
What causes Hypoxia and Ischemic Injury?
Strokes, Hypovolemic Shock, any profusion issue
What factors are involved with Increased Intracranial Pressure (ICP)
the amount of blood, brain tissue and CSF
What is the normal intracranial pressure?
0-15 mmHg while supine
Herniation
Displacement of brain tissue through skull
What is the brain protected by?
non-expandable skull and supporting septa
What do we do when there is ICP?
either drill a hole in the skull to drain the blood or if it is a CSF issue we can put a shunt in
What compensatory mechanisms does the brain have to control intracranial pressure?
Mainly controlling how much cerebrospinal fluid is pushed in and out of the brain cavity, also it can adjust Blood Pressure but this doesn’t affect the pressure nearly as much as controlling the CSF
What can cause ICP?
tumor, problems with vasculature (hemorrhagic stroke), hematoma, increased CSF, swelling from injury
What is Hydrocephalus?
abnormal increase in CSF volume in any part or all of the ventricular space
treatment: ventriculoperitoneal Shunt placement (so CSF can get out of the ventricular space)
What is a TBI?
traumatic brain injury
-structural damage to the brain and skull
could be an open head injury or closed
What is the leading cause of death of people under the age of 24?
TBI
What is the leading contributing factor/cause of TBIs?
lack of helmets and seatbelts
What are the 4 main types of Skull fractures (list)? What are the other types?
Simple (closed: skin is not broken)
Compound (open: skin is broken, laceration)
Depressed (like a cracked hard boiled egg)
Basilar
other types: linear, greenstick (incomplete fracture), comminuted (broken into 3 pieces or more)
Coup-Contrecoup
contusion resulting from a strong blow to the head, causing the brain to slam against the inside of the skull
Coup (primary)- injury of the brain where a direct hit has occurred
Contrecoup (secondary)- results when the brain impacts the side of the skull opposite the point of impact
- diffuse axonal injury
- widespread brain effects
- permanent brain injury
- coma/vegetative
Concussion
-recovery w/in 24 hours with mild concussions
S/S : headache, irritability
-s/s may persist for months (post concussion syndrome)
What is Post Concussion Syndrome?
where symptoms of the concussion can last days/weeks/months
-headaches, memory lapses
Traumatic Intracerebral Hematomas
- can occur in any lobe of the brain
- may be single or multiple
- occur most often in alcoholics and elderly (they fall a lot)
Vascular Deformity (AVM - arteriovenous malformation)
some vascular malformations lie deep in the brain and can cause hemorrhage directly into brain tissue
abnormal connection of the arteries and veins, by passing the capillary beds
-no exchange of gases…no capillary beds
-congenital
How can you know if you have a Vascular Deformity?
you wont know until you have a CT scan and it is found or it ruptures
Epidural Cerebral Hematoma
bleeding is rapid because of Skull Fracture and severance (ruptured) of Meningeal Artery
(bleeding between bone of skull and dura)
Subdural Cerebral Hematoma
bleeding is slow and results from tearing of veins that extend across the subdural (subarachnoid) space
- bleeding b/w dura and arachnoid space
- tearing of the small bridging veins
Acute Cerebral Hematoma
lasts 48 hours
s/s: could range from headache, ipsilateral SP?? (one sided) pupil that is fixed and dilated, confusion
Subacute Cerebral Hematoma
2-14 days
get better and then decline
S/S can be chronic
can have continual tears
seen in alcoholic and elderly (harder to diagnose in elderly)
What is a Cerebral Vascular Accident?
a stroke (requires rapid emergency treatment)
What are the major risk factors for CVA (stroke)?
Age, Gender (male), African American Heart disease, HTN high cholesterol Cigarette smoking prior stroke, diabetes Atrial Fibrillation (A-fib patients are high risk for throwing clots)
What are the two types of Stroke?
Ischemic and Hemorrhagic
What is a Ischemic stroke?
- interruption of blood flow in a cerebral vessel
- bloodless infarct of brain tissue caused by arterial Ischemia due to atherosclerotic blood vessels supplying the brain
What is a Hemorrhagic stroke?
- bleeding into brain tissue, associated with a much higher fatality rate than ischemic strokes
- usually caused by uncontrolled HTN