Neurological alterations pt 1 Flashcards
The brain does not have energy stores; it is dependent on ___.
aerobic metabolism
A brief interruption in blood supply-> significant ___
ischemic damage
A change in mental status is frequently not a ____.
primary neurological issue, so always remember to assess for other causes.
A drop in cardiac output will impact the ___
brain and other organs
The CNS is composed of:
Brain, Spinal cord, and cranial nerves I & II
The PNS is composed of:
Cranial nerves III-VII, Spinal Nerves, Peripheral components of the ANS
2 types of cells:
neurons and glial cells
Subjective neuro assessment includes:
- PMH/PSH
- Medications
3. Functional health patterns Health perception Nutrition/metabolic Elimination (urine, BM) Activity/exercise Sleep-rest Cognitive/perception Self-percept/self-concept Role-relationship Sexuality/reproductive Coping-stress Value-belief
Objective neuro assessment includes:
Mental status, Cranial nerve function, Motor function, Sensory function, Cerebellar function, Reflexes
Mental Status includes:
- Level of consciousness (awake, asleep, comatose)
- Orientation
- Cognition- responses to simple questions
- Motor activity
- Body posture
- Dress/hygiene
- Facial expression
- Speech pattern
Motor Function includes:
strength, tone (hypotonia and hypertonia), coordination (for ataxia), symmetry of muscle groups, pronator drift (motor cortex), involuntary movements (chorea), balance/coordination, gain, speech
how do you grade strength in the extremities?
+1 Trace movement
+2 Limb movement, but not against gravity
+3 Movement against gravity, but not against resistance
+4 Movement against some resistance
+5 Full strength
how do you assess for ataxia?
Cerebellar Function (balance)
- Gait assessment
- Romberg test
symptoms of Ataxia mimic those of being drunk,
such as slurred speech, stumbling, falling, and incoordination.
These symptoms are caused by damage to the cerebellum, the part of the brain that is responsible for coordinating movement.
How do you assess the motor cortex?
pronator drift test
region of the cerebral cortex involved in the planning, control, and execution of voluntary movements
Cerebral Blood Flow (CBF)
15-20% of total cardiac output
Brain uses 20% of the O2 in the body and 25% of glucose
Factors influencing CBF
i. CO2
ii. O2
iii. Hydrogen ion concentration
Cerebral Circulation
i. Brain makes up only 2% of total body mass, but requires 15-20% of total cardiac output
ii. Extremely sensitive to hypoxia; Any hypoxic damage to the brain becomes irreversible after only a few minutes
What are the 3 factors that influence cerebral blood flow (CBF)?
CO2, O2, Hydrogen ion concentration
An increase in CO2 and hydrogen ion level, decrease in O2 = NEGATIVE effect on CBF
What conditions cause a drop in cardiac output that could negatively affect the brain?
CO = SV x HR
- SV affected by dehydration and hemorrhage
- HR affected by dysrhythmias, bradycardia, hypothermia, beta blocker overdose, MI, cardiac arrest
- These are just a few examples
Intracranial Pressure (ICP)
the hydrostatic force measured in the brain CSF compartment
Normal ICP is 0 – 15 mmHg
↑ ICP > 20 mmHg for >5 minutes is an emergency
Measured by LP or with a ventriculostomy
3 components in the skull impact ICP: Brain tissue Blood CSF If one of these increases, another must drop OR will have brain damage from pressure
elevated ICP (intracranial pressure)
Cerebral edema
Increased cerebral blood volume
- Hypercapnia
- Hypoxemia
- Increased metabolic demands
- Increased intra-abdominal and intra-thoracic pressure
- Venous outflow obstruction
Too much CSF production
Cerebral Perfusion Pressure (CPP)
The net pressure gradient that drives oxygen delivery to cerebral tissue
MAP – ICP = CPP
Normal range = 60 – 100 mmHg
50 mmHg will maintain only basic cerebral functioning
< 30 mmHg = Ischemia and incompatible with life
What other non-neurological conditions can cause a change in mental status?
Examples include hypoglycemia and hypercapnia
Delirium
temporary, acute mental confusion that can be life-threatening; results in confused thinking and reduced awareness of surroundings.
Sudden onset (unlike dementia) Sometimes called post ICU symdrome Typically lasts 1-7 days, but can persist for longer and become chronic
Poorly understood
Contributing factors include:
1. Impairment of cerebral oxidative mechanism (i.e. insufficient oxygen, or trouble using the available oxygen)
2. Neurotransmitter abnormalities (e.g. Cholinergic deficiency, excess release of Dopamine)
3. Proinflammatory state
4. Cortisol excess
Risk factors: Older age, male gender, history of stroke/depression/dementia or other cognitive impairment, substance use history
Delirium can develop outside the hospital as a result of?
and inside the hospital?
Can develop outside the hospital as a result of:
- Alcohol or drug abuse
- Side effects of prescribed medications
- Polypharmacy
- Sleep deprivation
- Dehydration
- Electrolyte imbalances
- Glucose abnormalities
- A serious acute or chronic medical issue such as an acute infection, sepsis, liver failure, kidney failure, or thyroid hormone abnormalities
Can develop inside the hospital as a result of:
- All of the above, plus……..
- Unfamiliar environment
- Sensory overload or deprivation
- Emotional stress
- Pain
- Restraint use
delirium manifestations include:
Either
Hypoactivity and lethargy OR
Hyperactivity, agitation, hallucinations, misinterpretation, and impulsiveness
Others: inability to concentrate, disorganized thinking, irritability, insomnia, loss of appetite, restlessness, “picking” behavior, and confusion, “Sundowning”
