Neurology Flashcards
Divisions of the Brain
Cerebellum
Cerebrum
Brain Stem
Cerebrum
Divided into left + right hemispheres
Connected by corpus callosum
Interprets sensory impulses, controls voluntary muscles, memory, thought, reasoning
Cerebral Cortex
Outer layer of grey matter
Cerebral Medulla
White matter
Lobes of cerebrum
Frontal, parietal, temporal, occipital
Cerebellum
Controls posture and fine motor control
Meninges
Dura mater
Arachnoid mater
Pia mater
Supports structures and vasculature
Brainstem
Midbrain
Pons
Medulla oblongata
Midbrain
Just below cerebellum
Connects cerebrum to lower centers
Pons
Between mid brain and medulla
Conduction network between spinal cord and brain
Respiratory centre
Medulla Oblongata
Enlargement of cord as it enters cranial nerve through foramen magnum
Cardiac Centre
Vasomotor centre
Respiratory centre
Vomiting
Spinal Cord
From medulla to L1
Same coverings as brain
Reticular Activating System
Small portion of brain stem
Collection of neurons responsible for wakefulness and behaviour
Blood Supply to Brain
16% CO and 20% of total oxygen consumption
Supplied from carotid arteries
10s reserve
Constant supply of glucose
Drainage by jugular veins
Somatic Nervous System
Conscious control
Spinal + cranial nerves
Autonomic
Sympathetic
Parasympathetic
Spinal nerves #
31 pairs
Cranial nerves #
12
Nervous Tissue Function
Transmit nerve impulses
Interpretation
Storage (memory)
Nervous System Function
Receptors
Sensory Input
Integration center
Motor output
Effectors
Neurons
Relay impulse from body to spinal cord and brain
Messages from brain to all compartments of the body
Afferent
Sensory
Carry impulses toward brain and spinal cord from tissues and organs
Efferent
Motor
Carry away from brain and spinal cord
Interneurons
Connection between neurons
Exclusively in brain + spinal cord
3 Parts of Neurons
Dendrite
Cell body
Axon
Nervous Tissue Properties
Excitability
Conductivity
Cranial Nerve Names
I. Olfactory
II. Optic
III. Occulomotor
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII. Vestibulocochlear/auditory
IX. Glossopharyngeal
X. Vagus
XI. Spinal accessory
XII. Hypoglossal
Breakdown of Spinal Nerves
8 Cervical
12 Thoracic
5 Lumbar
5 Sacral
1 Coccygeal
Cervical Plexus
C1-C4
Skin and muscles of shoulder and neck
Diaphragm
Phrenic Nerve
Innervates diaphragm
C3,4,5
Brachial Plexus
C5-C8, T1
Skin and muscles of arm
Axillary nerve
Muscles of shoulder
Radial nerve
Back of arm, forearm, hand, thumb, 2 fingers (wrist drop)
Medial Nerve
Forearm, hand
Carpal tunnel
Ulnar Nerve
Wrist and hand muscles (claw hand)
Lumbosacral Plexus
T12, L1-5, S1-4
Lower torso + legs
Sciatic Nerve
Back of leg, buttocks
Femoral Nerve
Lower abdomen, front of thigh, medial leg and foot
Peroneal Nerve
Lateral leg, foot
Tibial Nerve
Back of leg, foot
Autonomic Neurotransmitters
Acetylcholine + Epinephrine
Cholinergic
Neurons releasing ACh (PNS)
Parasympathetic pre + post ganglionic neurons
Sympathetic preganglionic
Adrenergic
Neurons releasing epi (SNS)
Sympathetic post ganglionic
Sympathetic Chain Ganglia
Sympathetic axon collaterals bridge adjacent ganglia
In same side of vertebral column
Breakdown of Sympathetic Chain Ganglia
3 Cervical
11 Thoracic
4 Lumbar
4 Sacral
Alpha 1 receptors
Blood vessel vasoconstriction
Alpha 2 Receptors
Presynaptic neuron, eliminates release of NE
Beta 1
Heart, increases contractility and heart rate
Beta 2
Lungs, skeletal muscle, dilation
Norepinephrine
2 main receptors (alpha + beta)
NE Deactivation
2 enzymes MAO and COMT
Slower than ACh deactivation
Parasympathetic Neurons
Cell bodies in ganglion near effector organ
Synapse with one postganglionic neuron
Parasympathetic Effect
Restores vegetative function
Slows body function
Speeds up body functions (GI motility)
ACh deactivation
Acetylcholinesterase in synaptic cleft
2 Components of Consciousness
Content
Arousal
Anisocoria
Unequal pupils
Doll’s Eye Test
Move head side to side or up and down slow then quick
Should focus on fixed point
Abnormal is eyes fixed and move with head
Indicates brainstem dysfunction
Nystagmus
Involuntary but rhythmic oscillation of eyes
Hoover’s Sign
Flex contralateral leg against resistance
Involuntary extension of opposite leg won’t occur in cases of paresis with psychiatric etiology
Chair Test
Pts with gait disturbances
Propel self forward while seated, then walk same distance
Functional gait disturbance can ambulate chair but not standing
Scalp acronym
Skin
SubCutaneous tissue
Adipose
Ligament
Pericranium
Syncope
Transient complete LOC due to cerebral ischemia followed by recovery to mental status
Rapid onset
Short duration
Spontaneous complete recovery
Neually mediated syncope
Vasovagal
Carotid sinus sickness
Situational
Cardiac Syncope
Dysrhythmias
Structural disease
Cerebrovascular/neurologic syncope
Migraine
Subclavian steal
TIA
Carotid artery disease
Orthostatic Syncope
Autonomic failure
Drug-induced
Volume depletion
Patho Neurally Mediated Syncope
Autonomic reflex
Vasodilation + bradycardia
Systemic hypotension + cerebral hypo perfusion
LOC
Carotid Sinus Sickness
Over-activity or over-stimulation of carotid sinus
Quick head movement
Tight collar
Shaving over sinus area
Tumor or other growth
Emotional stress
Orthostatic Syncope Patho
Upright position causes hypotension and cerebral hypoperfusion without bradycardia
Standing up with exertion or with prolonged standing in crowds
Hypovolemia/faulty ANS
Medications affecting Orthostatic Syncope
Diuretics
B-adrenergic blockers
Anti-hypertensives
NTG
Common Dysrhythmias causing syncope
Transient VT
AV block
Sinus bradycardia
SVT, VF
Sick sinus syndrome
Pacemaker malfunction
Long QT
Structural Cardiac Syncope
Cardiac Ischemia
Outflow obstruction
Restrictive cardiomyopathy
Pericardial tamponade
PE
Aortic dissection
Congenital
Subclavian Steal
Occlusion/stenosis of subclavian artery or innominate artery
Causes retrograde flow in ipsilateral vertebral artery
Collateral pathway takes blood from contralateral vertebral artery and basilar artery to supply blood to arm
Pre-syncopal S/Sx
Weakness, headache, blurred vision, diaphoresis, n/v
Post Syncope S/Sx
Persistent drowsiness, headache, dizziness, nausea
S/Sx Cardiac Syncope
Chest pain
SOB
Palpitations
Supine syncope
Exercise syncope
S/Sx Reflex mediated syncope
Abdo pain
Nausea
Light-headedness
Seizures
Sudden change in behaviour due to excessive electrical activity in brain
Causes of Seizures
Electrolyte imbalances
Idiopathic
Epilepsy
Injury/head trauma
Infection
Brain tumor
Stork
Hypoglycemia
Drug use
Alcohol withdrawal
High fever
Eclampsia
Causes of Epilepsy
Stroke
Brain tumor
Brain infection
Past head injury
Metabolic problems
Neurological conditions
Genetic factors
Status Epilepticus
Prolonged seizures/numerous seizures without complete recovery between them (>5 min)
One constant seizure lasting longer than 5 min
Febrile Seizures
Fever >38
Child younger than 6
No CNS infection
NO metabolic abnormality
No history of previous seizures
Generalized vs focal
Short
Single rather than multiple
Benzodiazepine Actions
Enhance binding of GABA to GABA receptors in CNS
Opening of Cl channels
Hyperpolarization of cell membrane, decreasing ability to reach action potential
Midazolam
Short acting water soluble
Rapid administration causes hypotension + respiratory depresison
Phenytoin
Dilantin
Alters neuronal membrane permeability to sodium
Stabilizes membranes and suppresses firing
Does not act as CNS depressant
Effective in partial seizures + tonic-clonic and status
Worsens petit man
Crosses placental barrier
Carbamazepine
Tegretol
Blocks neuronal sodium channels
Inhibits repetitive action potentials
Drug for partial seizures
CNS depressant and eventually hepatotoxic
Metabolism inhibited by several drugs
Phenobarbital
Unknown mechanism but generally CNS depressant
Effective in treatment of recurrent seizures
Acute presentations of tonic-clonic and in adults that don’t respond to diazepam
Risk of rebound seizures
Valproic Acid
Enhances neuronal inhibitory synapses
Myoclonic seizures
Primidone
Similar to phenobarbital
Benzodiazepine Antidote
Flumazenil
Adverse effects Midazolam
CNS depression
Resp depression
Hypotension
N/v
Paradoxical CNS stimulation
Profound risk in elderly, debilitated, chronic illness
IV Pharmacokinetics Midazolam
Sedation in 3-5 min
Anterograde amnesia in 1-5 min, persists for 20-40 min
Elimination in 1.8-6.4
IM Pharmacokinetics Midazolam
Peak concentration in 30 min
Peak sedation 30-60 min
Duration ~1hour
Midaz Routes Preferred
Adults: IM -> IV
Ped: Buccal -> IN -> IM
Ketamine MOA
Blocks NMDA of GABA receptors
Antidepressive effects due to blockage of HCN1 receptors
Affect on cholinergic, aminergic and opioid systems
Side Effects Ketamine
Tachycardia
HTn
Increased ICP
Laryngospasm
Hypersalivation
N/v
Confusion, hallucination, paranoia
Impaired motor coordination
Anterior Circulation Stroke
Most common
Like typical stroke
MCA, ACA, and anterior choroidal artery
Posterior Circulation Stroke
Difficult to detect with vague, non-specific symptoms
Episodic Vestibular Syndrome
Symptoms resolved
Vasovagal/panic attack
Triggered Vestibular Syndrom
Pt sits up and dizzy, resolves when back down
Trigger causes symptom, removal of trigger resolves symptoms
Acute Vestibular Syndrome
Persistent Symptoms
Trigger, but no improvement with removal of trigger
Possible posterior circulation stroke
Pontine Stroke S/Sx
Pinpoint pupils
Bilateral paralysis/weakness
Vertigo
double vision
Locked in syndrome
CVA Mimickers
Hypoglycemia
Encephalopathy
Metabolic
Infections
Systemic
Mass lesions
Migraines
transient global amnesia
Todd’s Paralysis
Post-ictal hemiparesis
Focal weakness to one side post seizure lasting 20 min - 48 hours
Corticospinal Tract
Damage causes ipsilateral weakness, spasticity, increased deep tendon reflexes, babinski’s sign
Spinothalamic tract
Damage causes loss of pain + temperature sensation
Dorsal Column
Injury causes ipsilateral loss of vibration and proprioception sensation
Neurogenic Shock
Loss of vasomotor tone and sympathetic nervous system tone
Hypotension + bradycardia + poikilothermia
Occurs within 30 min of cord injury T5 or above, lasts up to 6 weeks
Spinal Shock
Acute spinal cord injury
Absence of all voluntary and reflex neurologic activity below site of injury
Lasts days to months
Neurogenic Pulmonary Edema
Form of ARDS, increase in pulmonary interstitial and alveolar fluid
Caused by seizures, cerebral hemorrhage, head injury
S/Sx of Neurogenic Pulmonary Edema
Sudden dyspnea, mild hemoptysis
Tachypnea
Tachycardia
Bibasilar crackles
Respiratory distress
Pulmonary edema with normal JV pressure and absence of cardiac gallop
Fever
Autonomic Dysreflexia
Body’s resolution of effects of spinal shock
Injuries at or above T6
Sudden HTN, bradycardia, headache, blurred vision, sweating + flushing skin
Myasthenia Gravis
Auto immune neuromuscular disorder
Signs of muscle weakness of voluntary muscles
Reduction in ACh receptors at synaptic cleft
S/Sx Myasthenia Gravis
Drooping eyelids
Double vision
Slurred speech
Nasal quality to speak
Drooling
Nasal regurgitation
Weak cough
problems chewing + swallowing
Trouble sitting up/holding head erect
Trouble walking
Feeling SOB
Complications of Myasthenia Gravis
Myasthenia crisis
Cholinergic crisis
Pneumonia
Sepsis
Complications related to immobility
Respiratory distress
Choking
Bells Palsy
Rapid onset
15-60 yo
7th cranial nerve affected
Unilateral/bilateral facial weakness
Majority have full recovery
Causes of Bells Palsy
Infection
Hemorrhage
Tumor
Meningitis
Local trauma
S/Sx Bells Palsy
Unilateral facial weakness
Aching pain around angle of jaw/behind ear
Headache
tearing
Unilateral mouth drooling + drooping
Inability to control facial expression in smiling, squinting, blinking/closing eyelid
Loss of sensation of taste
Complications Bell’s Palsy
Corneal ulceration + blindness
Impaired nutrition
Long-term psycho social problems
Guillan Barre Syndrome
Widespread inflammation or demyelination of ascending/descending nerves in peripheral nervous system
Weakness/paralysis
Muscles unable to respond to commands from brain due to decreased conduction
Cause of Guillian Barre Syndrom
Unknown
>50% non specific infection 10-14 days prior
S/Sx Guillian Barre
Lower extremity weakness leading to upper extremity and facial weakness
Sensory and motor loss
Complete paralysis with respiratory failure within 48 hours
Paralysis progressing in 2-3 weeks
HTN
Hypotension
Dysrhythmias
Circulatory collapse
Complications Guillian Barre
Cardiac failure
Respiratory failure
Infection + sepsis
Venous thrombosis
Pulmonary embolus
Cause of Parkinson’s
Lack of cells producing dopamine
Inability to relay information from cell to cell
S/Sx of Parkinsons
Muscle rigidity and akinesia
Jerky tremor
Difficulty walking
High pitched monotone voice
Mask like facial expression
Loss of posture control
Difficulty speaking/swallowing
Decreases with purposeful movement and sleep
ALS
Progressive degeneration of nerve cells in spinal cord and brain
Unknown cause, suspected excess glutamate
S/Sx ALS
Twitching + cramping muscles
Loss of motor control in hands + arms
Increased weakness in diaphragm and chest muscles
tripping and falling
Fatigue
Slurred/thick speech
Difficulty breathing + swallowing
Paralysis
Cardiac arrhythmia
Pneumonia
Respiratory arrest
