Neuro 306- In class lecture

What defines Epilepsy versus a single seizure event?

Epilepsy is a chronic disorder of recurrent unprovoked seizures caused by sudden bursts of abnormal electrical activity.

What defines a seizure?

An abnormal electrical discharge from neurons causing a discrete clinical event with variable symptoms.

What defines seizure disorders?

A group of disorders characterized by excessive excitability of neurons in the central nervous system.

What is the typical age of onset for epilepsy and what does onset after age 20 suggest?

Onset is most common in childhood; onset after age 20 usually indicates an underlying structural brain cause.

How do seizures differ from convulsions?

A seizure is an abnormal electrical discharge in neurons, while a convulsion is a violent involuntary muscle contraction (not all seizures involve convulsions).

In generalized seizures, neurons will not _______ enough, causing….

Generalized seizures represent a classic picture of neurons not repolarizing enough, which lowers the seizure threshold.

What is the fundamental cellular imbalance that triggers a seizure?

Excitatory neurotransmission exceeds inhibitory neurotransmission in the brain.

How does GABA deficiency affect the seizure threshold?

GABA is the main inhibitory neurotransmitter, so having not enough GABA lowers the threshold and can cause a seizure.

What metabolic and environmental factors alter the seizure threshold?

Fluid/electrolyte imbalances, cerebral edema, inflammation, substances that increase excitability, systemic stress, and sleep deprivation.

How do focal seizures originate?

Focal seizures start in one specific part of one cerebral hemisphere and stay localized or spread.

How do generalized seizures originate?

Generalized seizures originate simultaneously across both cerebral hemispheres.

What motor cues characterize focal seizures?

Unilateral clonus (twitching), postural stiffening (tonic), impaired awareness, and automatisms.

What are automatisms in focal seizures?

Involuntary, semi-purposeful repetitive movements (e.g., lip-smacking, chewing, hand rubbing) typical in temporal lobe seizures.

What sensory and non-motor cues can accompany focal seizures?

Unilateral tingling, electric shock sensations, pain, sensory aura, deja-vu, jamais-vu, and autonomic cues.

What is the clinical significance of a sensory aura in focal aware seizures?

An aura is often a warning sign of secondary generalization into a full seizure.

During generalized seizures what do patients often lose control of?

Patients frequently lose control of bladder or bowel function during generalized seizures.

What characterizes the Tonic phase of a Tonic-Clonic seizure?

Loss of consciousness, muscle stiffness, cyanosis, and tongue biting.

What characterizes the Clonic phase of a Tonic-Clonic seizure?

Violent, rhythmic muscle jerking.

What characterizes the Postictal state following a Tonic-Clonic seizure?

Lethargy, confusion, and potential airway compromise or aspiration risk.

What defines an Atonic seizure ("drop attack") and its key safety consideration?

Sudden loss of postural tone lasting under 2 seconds; poses an extreme head injury risk requiring helmet safety.

What characterizes Myoclonic seizures regarding consciousness?

Brief, lightning-fast shock-like muscle twitches bilaterally without loss of consciousness.

What characterizes an Absence (Petit Mal) seizure and its EEG correlate?

Brief (5-10 sec) staring spells with immediate recovery, showing a 3 Hz spike-and-wave pattern on EEG (often misdiagnosed as ADHD or daydreaming).

What distinguishes Focal Aware from Focal Impaired Awareness seizures?

In Focal Aware (simple partial), consciousness remains intact; in Focal Impaired Awareness (complex partial), consciousness is altered or lost.

What nursing safety action is essential during a Focal Impaired Awareness seizure?

Do not restrain the patient; clear the area of hazards and support them during post-event confusion.

What is Psychogenic Non-Epileptic Seizures (PNES)?

Paroxysmal seizure-like events stemming from psychological causes (unmanaged trauma or anxiety/PTSD) rather than abnormal electrical brain activity.

What EEG finding is expected during a PNES event?

A completely normal EEG during the event because symptoms are not caused by abnormal brain waves.

What clinical features help distinguish PNES from epileptic seizures?

Gradual onset, side-to-side head shaking, closed eyelids during event, partial responsiveness, and rapid postictal reorientation.

How is PNES diagnosed and treated?

Diagnosed with video EEG; treated with psychotherapy and psychotropic meds for anxiety/PTSD (not anti-seizure meds).

What defines Status Epilepticus?

A medical emergency defined as a continuous seizure lasting >= 5 minutes OR 2+ discrete seizures without returning to normal mentation in between.

What nursing actions and timeframes are critical during Status Epilepticus?

Track time, symptoms, and pre-seizure activity; note that most seizures end in 1-2 minutes, and abortive meds (benzos/ASDs) are given if it reaches 5 minutes.

What percentage of seizure cases can be controlled with anti-seizure drugs?

Approximately 70% of seizure cases can be controlled with medications alone.

What is a key diagnostic limitation of an EEG in epilepsy?

EEG is not super accurate and gives false negatives if not recorded during an actual seizure.

What is the role of surgery in epilepsy management?

Surgery (such as focal resection or corpus callosotomy) is an option to remove the seizure focus or prevent seizure spread.

What is the State of Michigan driving rule for patients with seizures?

Patients cannot drive unless they have been completely seizure-free for 6 consecutive months, regardless of the cause.

What are polygenic epilepsies?

The most common genetic epilepsy pattern, where multiple small gene mutations lower the overall seizure threshold.

What is Dravet Syndrome?

A severe infantile monogenic epilepsy caused by SCN1A gene mutations affecting sodium channels (autosomal dominant).

What is PRRT2-associated epilepsy?

The most common monogenic epilepsy, an autosomal dominant disorder associated with infantile seizures.

What is SLC2A1 / GLUT1 Deficiency Syndrome and how is it treated?

An autosomal recessive disorder impairing glucose transport into the brain; treated with a Ketogenic Diet.

What are de novo mutations in epilepsy?

Spontaneous new genetic mutations developing during egg/sperm formation or early embryonic development.

What is Guillain-Barré Syndrome (GBS)?

An acute, rapidly progressive, and potentially fatal autoimmune disorder causing acute demyelinating polyneuropathy of peripheral nerves.

What events typically precede Guillain-Barré Syndrome?

Viral infection, surgery, Hodgkin's disease, or certain vaccinations.

What is the prevalence and recovery rate of Guillain-Barré Syndrome?

Occurs equally in men and women (ages 30-50 most common); 80-90% of patients recover with minimal or no residual symptoms.

What is the characteristic pattern of paralysis in Guillain-Barré Syndrome?

Symmetrical ascending paralysis starting mid-legs ("rubbery/very heavy legs") and progressing upward.

How are deep tendon reflexes affected in Guillain-Barré Syndrome?

Deep tendon reflexes (like the knee-jerk reflex) disappear early in the disease.

What sensory symptoms occur in Guillain-Barré Syndrome, and is there numbness?

Pain and tingling are very common, but there is no numbness.

What autonomic symptoms can occur in Guillain-Barré Syndrome?

Postural hypotension, cardiac arrhythmias, facial flushing, sweating abnormalities, and urinary retention.

What is "The Danger Zone" in Guillain-Barré Syndrome?

Respiratory muscle failure as ascending paralysis reaches the diaphragm and intercostals.

What is the primary medical goal during progressive Guillain-Barré Syndrome?

To stop progressive paralysis before it reaches its natural stopping point.

What is the Plateau Period in Guillain-Barré Syndrome?

The phase where disease progression stops because the autoimmune attack ceases.

Why is recovery slow in Guillain-Barré Syndrome and how long can it take?

Recovery takes weeks to years because it depends on regenerating damaged peripheral nerves.

What medical therapies are used to treat Guillain-Barré Syndrome?

Plasmapheresis (separating plasma to remove autoantibodies), IVIG (IV immunoglobulin), and supportive care.

Which division of the nervous system is affected by Multiple Sclerosis?

Autoimmune destruction of myelin in the Central Nervous System (CNS only; does not affect the PNS).

What is the typical demographic and age of onset for Multiple Sclerosis?

Affects women more than men, typical onset at reproductive age (20-40 years), most common in Northern European ancestry (uncommon in Asia, Africa, South America).

What genetic marker and family history risk are linked to Multiple Sclerosis?

10-20% family history risk; strongly associated with the HLA-DR2 haplotype.

What cellular mechanism drives Multiple Sclerosis pathogenesis?

Autoreactive T-cells and B-cells cross the BBB and attack myelin sheaths and oligodendrocytes, leaving behind plaques/sclerosis.

Which CNS regions have a strong affinity for autoantibody attack in MS?

Optic nerves, periventricular white matter, brainstem, cerebellum, and spinal cord white matter.

What causes permanent, irreversible disability in Multiple Sclerosis?

Axonal degeneration following repeated demyelination and plaque formation.

What is the McDonald Criteria for diagnosing Multiple Sclerosis?

Demonstrating Dissemination in Space (>= 2 distinct CNS lesion sites) AND Dissemination in Time (or positive CSF oligoclonal bands / kappa light chains).

What diagnostic tests are used to confirm Multiple Sclerosis?

MRI (showing lesions or central vein sign), OCT, VEP, and Lumbar Puncture (CSF oligoclonal bands & kappa free light chains).

What visual and sensory cues are common in Multiple Sclerosis?

Optic neuritis (vision loss, diplopia, blurred vision), paresthesias (tingling/prickling), numbness, and neuropathic pain.

What motor and cognitive cues occur in Multiple Sclerosis?

Spasticity, unsteady gait, ataxia, dysarthria, dysphagia, paraplegia/quadriplegia, urinary retention, constipation, fatigue, and memory impairment.

What characterizes Relapsing-Remitting MS (RRMS)?

Most common pattern (85-90%), featuring clear flare-ups (relapses) followed by recovery (remissions) with no disease progression between flares.

What is the main goal of treatment in Relapsing-Remitting MS?

Treatment aims to prevent relapses and decrease flare severity (cannot reverse structural damage).

What characterizes Secondary Progressive MS (SPMS)?

Evolves from RRMS over time (~50% of cases), leading to steady neurological worsening with fewer or no remissions.

What characterizes Primary Progressive MS (PPMS)?

Rare form (10%) where patients steadily worsen from the beginning without remissions or previous RRMS.

What is the pathophysiology of Myasthenia Gravis?

Autoimmune antibody attack on nicotinic acetylcholine receptors (nAChRs) or MuSK receptors at the neuromuscular junction, blocking ACh binding.

What is the typical demographic for Myasthenia Gravis?

Can occur at any age but most common in young adulthood; affects females more than males.

How does physical exertion affect muscle weakness in Myasthenia Gravis?

Weakness worsens with exertion because acetylcholine (ACh) stores run out with repeated muscle use.

What ocular and facial cues occur in Myasthenia Gravis?

Ptosis (drooping eyelid), diplopia (double vision), blurred vision, flat facial expression, weak smile, and jaw fatigue.

What bulbar and respiratory cues occur in Myasthenia Gravis?

Dysarthria, dysphagia, nasal speech, difficulty chewing, weak cough, shallow respirations, and dyspnea.

Why is a Thymectomy performed in Myasthenia Gravis?

Performed because an enlarged, overactive thymus gland contributes to autoantibody production.

What is the underlying cause of a Myasthenic Crisis while taking meds

Too little medication (or triggered by infection, stress, or surgery), leaving inadequate ACh at receptors.

What is the primary life threat in a Myasthenic Crisis?

Respiratory failure due to extreme weakness of the diaphragm and intercostal muscles.

What are the systemic/autonomic signs during a Myasthenic Crisis?

Sympathetic or normal signs: tachycardia, normal pupils, dry skin, and absent/mild GI symptoms.

What is the underlying cause of a Cholinergic Crisis?

Overdose/toxicity of acetylcholinesterase inhibitors (pyridostigmine), causing an ACh surplus that desensitizes receptors.

What is the primary life threat in a Cholinergic Crisis?

Respiratory failure due to muscle weakness combined with excessive bronchial secretions (bronchorrhea) and bronchospasm.

What musculoskeletal sign occurs in a Cholinergic Crisis?

Fasciculations (muscle twitching/rippling under the skin) and flaccid paralysis.

What autonomic signs characterize a Cholinergic Crisis (SLUDGE / DUMBELS)?

Salivation, Lacrimation, Urination, Diarrhea, GI cramps, Emesis, plus bradycardia, miosis (pinpoint pupils), excessive sweating, and bronchorrhea.

What is the Ischemic Core in a stroke?

The central brain region directly affected by vascular blockage where severe oxygen deprivation causes rapid, permanent cell death.

What is the Ischemic Penumbra and what is the key clinical goal?

The surrounding tissue with reduced blood flow that is functionally stunned/impaired but salvageable; the main medical goal is to SAVE THE PENUMBRA!

What percentage of cardiac output is consumed by the brain?

The brain consumes approximately 1/6 to 1/5 (16%-20%) of total cardiac output.

What is the normal Mean Arterial Pressure (MAP) range for efficient cerebral autoregulation?

Efficient cerebral autoregulation occurs between a MAP of 60 to 140 mmHg.

What occurs when Mean Arterial Pressure (MAP) drops below 60 mmHg?

Vasodilation hits its maximum limit, blood flow drops linearly, and oxygen delivery to the brain decreases, causing ischemic injury, dizziness, or syncope.

What occurs when Mean Arterial Pressure (MAP) exceeds 140 mmHg?

Vasoconstriction hits its maximum limit, forcing vessels open, breaking down the blood-brain barrier, and causing cerebral edema or hyperperfusion injury.

What is the clinical definition of a stroke?

A focal neurological deficit resulting from an interruption or reduction of blood supply to part of the brain.

What are the three primary types of cerebrovascular events?

Ischemic Stroke, Hemorrhagic Stroke, and Transient Ischemic Attack (TIA).

What is a thrombolytic ischemic stroke?

An ischemic stroke caused by a blood-based clot forming directly inside a brain vessel.

What is an embolic ischemic stroke?

An ischemic stroke caused by a clot, air, or debris traveling through the bloodstream from another location (often the heart) to block a brain vessel.

What are the primary mechanical classifications of embolic ischemic strokes?

Cardioembolic, arterial (atherosclerosis), structural (PFO, DVT, hypercoagulable states, ESUS), and cryptogenic.

What are non-modifiable risk factors for stroke?

Advancing age, sex, race/ethnicity (higher in African American, Hispanic, South Asian, and Indigenous populations), family history/genetics, and prior history of stroke or TIA.

How does stroke risk vary by age and sex?

Under age 30, stroke incidence is higher in women; in mid-life, incidence is higher in men; in later life, incidence is higher in women.

What are major modifiable risk factors for stroke?

Hypertension, diabetes mellitus, high cholesterol, atrial fibrillation/valvular heart disease, tobacco use, obesity, sedentary lifestyle, substance use, diet, OSA, and HRT.

What are the main mechanical classifications of ischemic stroke?

Large artery thrombus, small penetrating (lacunar), embolic, and cryptogenic (unknown origin).

How quickly does brain cell death begin after blood flow is cut off?

Brain cell death begins within 4 to 6 minutes of lost blood supply.

What is the Ischemic Core in a stroke?

The central area directly affected by blood blockage where severe oxygen deprivation causes rapid, permanent cell death.

What is the Ischemic Penumbra?

The surrounding brain tissue receiving reduced or collateral blood flow that is functionally stunned/impaired but still salvageable.

What is the primary medical goal when managing an acute ischemic stroke?

SAVE THE PENUMBRA before the salvageable tissue converts into permanent ischemic core!

What is a Transient Ischemic Attack (TIA)?

A temporary cerebral blood flow disturbance ("mini-stroke") caused by a micro-thrombus or micro-embolus that reverses prior to cell infarction.

What are common vascular sources of micro-emboli in a TIA?

Carotid artery atherosclerotic plaque and Atrial Fibrillation.

Why is a Transient Ischemic Attack (TIA) difficult to truly diagnose on CT imaging?

Because a TIA resolves quickly and will not show evidence of acute infarction on a CT scan or MRI.