Cranial Nerves Quiz

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Questions and Answers

What is the primary function of the glossopharyngeal and vagus nerves?

Regulation of blood flow only

Sensory function only

Motor function only

Both motor and sensory functions (correct)

Where do the glossopharyngeal and vagus nerves originate?

Spinal cord

Cerebral cortex

Medulla oblongata (correct)

Cerebellum

Which of the following is a symptom that may occur during the prodromus stage of a seizure?

Loss of consciousness

Muscle convulsions

Difficulties in sleeping (correct)

Tonic immobility

What happens to cerebral oxygen demand during a seizure?

It increases by 60% Signup and view all the answers

How should the vagus nerve's impact on heart rate be described?

It slows down heart rate Signup and view all the answers

What is the initial alteration in perception that often occurs before a seizure called?

Aura Signup and view all the answers

Which term describes the actual period during which a seizure occurs?

Ictus Signup and view all the answers

What assessment can be used to test the strength of the accessory nerve?

Turning the head against resistance Signup and view all the answers

What measurement describes the increased demand for energy during seizure activity?

ATP demand increases by 250% Signup and view all the answers

During which phase can focal weakness known as Todd's paresis occur?

Post-ictal phase Signup and view all the answers

What is assessed when a patient is asked to stick their tongue out?

Function of the hypoglossal nerve Signup and view all the answers

What condition is characterized by at least two unprovoked seizures occurring more than 24 hours apart?

Epilepsy Signup and view all the answers

Which of the following symptoms is NOT typically associated with the post-ictal phase?

Muscle jerking Signup and view all the answers

Which of the following is a common source of seizures in individuals over 65 years old?

Cerebrovascular disease Signup and view all the answers

What characterizes an acute symptomatic seizure?

Seizure occurring as a result of an underlying systemic insult Signup and view all the answers

What is the term for the combination of sustained muscle contraction followed by rhythmic jerking during a seizure?

Tonic-clonic Signup and view all the answers

What is a potential conservative treatment approach for managing a haemorrhagic stroke with increased ICP?

Maintaining balance of BP Signup and view all the answers

What symptom might indicate a life-threatening secondary headache?

Head trauma Signup and view all the answers

Which condition is associated with neurogenic shock?

Spinal cord injury at T6 or above Signup and view all the answers

What is an appropriate non-narcotic analgesia for treating headaches in acute cases?

Paracetamol Signup and view all the answers

Which of the following is NOT a common cause of secondary headaches?

Tension-type headaches Signup and view all the answers

What is a recommended action when treating a patient exhibiting signs of increased ICP?

Raise the head of the stretcher 30 degrees Signup and view all the answers

What occurs in neurogenic shock related to sympathetic tone?

Decreased inotropy and chronotropy Signup and view all the answers

Which factor is NOT associated with the characteristics of a haemorrhagic stroke?

Presence of localized pain in the limbs Signup and view all the answers

Which symptom is NOT commonly associated with bradycardia?

Muscular rigidity Signup and view all the answers

What is a primary treatment for managing hypertensive crises in patients with bradycardia?

Positioning the patient upright Signup and view all the answers

Which of the following indicates a severe response to malignant hyperthermia?

Hypercapnia Signup and view all the answers

Which of the following is a possible sign of rhabdomyolysis associated with malignant hyperthermia?

Brown or bloody urine Signup and view all the answers

What is the role of the corticobulbar tract in the motor system?

Modulation of facial movements Signup and view all the answers

Which condition would most likely cause symptoms such as tachycardia and acidosis?

Malignant hyperthermia Signup and view all the answers

What is NOT a treatment option for managing bradycardia?

Stopping causative drugs Signup and view all the answers

Extrapyramidal reactions are primarily associated with which type of medication?

Antipsychotic drugs Signup and view all the answers

What is a possible consequence of untreated severe hyperpyrexic emergencies in Parkinson's patients?

Fatal outcomes Signup and view all the answers

What characterizes Amyotrophic lateral sclerosis (ALS)?

Progressive muscle weakness leading to respiratory failure Signup and view all the answers

Which age group is predominantly affected by Multiple Sclerosis?

Young adults aged 20-40 Signup and view all the answers

In Myasthenia Gravis, where is the main destruction occurring?

At the postsynaptic neuromuscular junction Signup and view all the answers

A commonly observed symptom in Myasthenia Gravis is:

Episodic muscle weakness Signup and view all the answers

What can trigger acute psychotic episodes in Parkinson's patients?

Concomitant infections Signup and view all the answers

What is a defining feature of Multiple Sclerosis attacks?

Vary widely with symptoms such as weakness and vision problems Signup and view all the answers

What is a potential outcome of a myasthenic crisis?

Hypopnea or apnea Signup and view all the answers

Study Notes

Cranial Nerves

Glossopharyngeal & Vagus nerves: Both have motor and sensory functions, sending sensory information from the nose, throat, and tongue.
Glossopharyngeal provides taste for the back of the tongue and controls voluntary movement of muscles in the back of the throat.
Vagus nerve controls communication sensation information from the ear canal and throat, sensory information from the heart and intestines.
Vagus nerve innervates the SA and AV nodes of the heart, slowing down heart rate when innervated.
Vagus nerve also innervates muscles in the throat, chest, and trunk, as well as taste near the root of the tongue.
Vagus nerve has the longest pathway among all cranial nerves.
To assess the glossopharyngeal and vagus nerves:
- Have the patient open their mouth wide and say "ahh". Look at the uvula in the back of their throat as they do this. The uvula should stay in a midline position.
- Ask the patient to swallow - they should be able to.
Accessory Nerve: Controls muscles in the neck, allowing for extension, flexion, and rotation.
Accessory nerve has two parts: a spinal portion that supplies muscles in the neck and a cranial portion that follows the vagus nerve.
To assess the accessory nerve:
- Have the patient turn their head to each side against resistance from your hand. They should have equal strength on each side.
- Alternatively, assess their ability to shrug by having the patient shrug their shoulders against resistance from your hands. The shrug should be strong and symmetrical.
Hypoglossal Nerve: Controls movement of most of the muscles in the tongue.
To assess the hypoglossal nerve:
- Have the patient stick their tongue out. It should stick out straight, not to one side.

Seizures

Seizures are a temporary disruption of brain function caused by uncontrolled excessive neuronal activity.
Seizures reflect an electrical problem in the brain that manifests as altered sensations and/or activity in the body.
Maintaining seizure activity requires a 250% increase in ATP demand in the brain.
Cerebral oxygen demand increases by 60%.
Cerebral blood flow increases by 250% due to increased demand during a seizure.
This increase in demand leads to rapid depletion of oxygen and glucose, potentially causing hypoxia and hypoglycemia.

Stages of a Seizure

Prodromal: The period of time from the first symptoms to the full development of the seizure. Can last hours to days before a seizure.
- Often includes symptoms like difficulty sleeping, behavioral changes, or other subtle changes.
Aura: The initial alterations in perception during a seizure.
- Usually lasts minutes to seconds, often the first part of a seizure.
- May include altered emotions, hearing, smell, taste, or vision.
Ictus: The period of the seizure itself.
Post-ictal: The state of confusion that may last minutes to hours after a seizure.
- Symptoms may include drowsiness, confusion, nausea, hypertension, headache, fatigue, incontinence, fear and anxiety, trouble walking, hypoglycemia, and tachycardia.

Motor Symptoms in the Ictal Phase

Tonus: Sustained muscle contraction.
Clonus: Muscle jerking in a rhythmic way.
Tonic-clonic: Sustained contraction followed by rhythmic jerking.
Atony: Muscle flaccidity.
Trismus: Tone/clenching of the jaw, restricting mouth opening.

Post-Ictal Phase

Todd's Paresis: Focal weakness in a part of the body, typically unilateral in the limbs.
- May also affect gaze, speech, or vision, impacting up to 13% of seizures.
- Because it can mimic stroke, it is crucial to determine which occurred first.

Seizures vs Epilepsy

A seizure is a transient occurrence of signs and symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Epilepsy is a brain disease characterized by:
- At least 2 unprovoked seizures occurring more than 24 hours apart.
- Or one unprovoked seizure with a high probability of further seizures.
Epilepsy can be considered resolved under certain conditions:
- If there is an age-dependent diagnosis and the patient has passed that age.
- If the patient has remained seizure-free for the past 10 years without taking seizure medications for the last 5 years.

Acute Symptomatic Seizure

A seizure occurring at the time of, or in close temporal relationship with, a central nervous system or systemic insult.
Also known as a reactive or provoked seizure.
The seizure is a symptom of another event.

Etiology of Seizures

Cerebrovascular, trauma, CNS infection, withdrawal, metabolic, toxic, or other causes.
For individuals over 65, cerebrovascular disease, such as stroke, is responsible for two-thirds of seizures.

Cerebrovascular Disease as a Cause of Seizures

Ischemia, hemorrhagic CVA/stroke, cerebral venous thrombosis, and vascular malformation.

Hemorrhagic Stroke

Bleeding into the brain tissue can be caused by hypertension, aneurysm, or arteriovenous malformations.
Treatment is primarily conservative, aiming to manage blood pressure, intracranial pressure, and blood glucose.

Secondary Headaches- Life Threatening Causes

Trauma to the head or neck.
CVA or cerebral vasculitis.
Tumors and increased intracranial pressure.
Seizures.
Medications or positions (nitrates cause vasodilation, carbon monoxide poisoning).
Infections (meningitis, encephalitis).
Hypertension, dehydration, renal or thyroid problems.

Headache Treatment

Gentle handling, reduce stimuli (lights, noise, sirens).
Non-narcotic analgesia (paracetamol).
Antiemetics (prochlorperazine).
Raise the stretcher head 30 degrees to help decrease intracranial pressure.
Transport to a neuro center if the patient has any red flags.

Neurogenic Shock

Shock occurring in the setting of normal blood volume (normovolemic hypotension).
Haemodynamic instability occurs in the setting of spinal cord injury at the level of T6 and above.
Related to loss of sympathetic tone to the peripheral vasculature and heart.
Significant loss of sympathetic division past T6, but large preservation of parasympathetic.
Loss of sympathetic tone prevents regulation of the peripheral vascular and heart.
Loss of sympathetic tone also disrupts the ability to stimulate adrenal glands to release catecholamines (adrenaline and noradrenaline).
This results in a loss of vascular tone, decreased inotropy (contractility), and decreased chronotropy (heart rate).
Symptoms include bradycardia, pounding headaches, nausea, anxiety, blurred vision, and nasal obstruction.

Neurogenic Shock Signs and Symptoms

Profuse sweating and flushing above the lesion (often face, neck, shoulders), with goosebumps below the injury.
The severity of attacks ranges from asymptomatic hypertension to hypertensive crisis, followed by profound bradycardia, cardiac arrhythmias or arrest, intracranial haemorrhage, and seizures.

Neurogenic Shock Treatment

Monitoring of blood pressure.
Positioning the patient upright to orthostatically lower blood pressure.
Removal of tight-fitting garments.
Searching for and correcting any noxious inciting stimuli.
Bladder distension, pressure areas, wounds, ingrown toenails, fractures.
Nitrates (GTN 300-600 mcg, repeat @ 10/60 intervals).

Malignant Hyperthermia

A rare, severe, and life-threatening hyperthermic response to medications, usually triggered by the combination of an inhaled anesthetic and a depolarizing neuromuscular blocker.

Malignant Hyperthermia Signs and Symptoms

Muscular rigidity, especially of the jaw (often the first sign).
Tachycardia or other dysrhythmias.
Tachypnoea.
Acidosis.
Shock.
Hyperthermia, with temperature usually above 40 degrees Celsius but can progress to extremes above 43 degrees Celsius.
Hypercapnia, as detected by an increased EtCO2.
Urine may appear brown or bloody if rhabdomyolysis and myoglobinuria have occurred.

Malignant Hyperthermia Treatment

Stop the causative drug immediately.
Aggressively cool the patient.
Immediate transfer to a hospital for dantrolene (muscle relaxant) to stop the hyperthermia.

Extrapyramidal Reactions

Related to the pyramidal system (motor pathways that control voluntary movement) and extrapyramidal tracts (motor pathways that control involuntary movement).
Extrapyramidal reactions are serious neurological symptoms that may occur after initiation of antipsychotic drugs.
Fluctuations in drug levels can lead to an acute exacerbation of Parkinson-like symptoms.
Severe, hyperpyrexic emergencies are possible, with altered consciousness, severe rigidity, and rhabdomyolysis.
Acute psychotic episodes, especially with concurrent infections.
Dystonic reactions may also occur.

Amyotrophic Lateral Sclerosis (ALS)

Progressive degeneration of upper and lower motor neurons.
Results in progressive muscle weakness leading to respiratory failure and death, typically within 2-5 years of onset.
Muscle atrophy occurs due to disuse caused by the loss of nerve innervation.
As the disease progresses, respiratory muscles are eventually affected.
Patients become apnoeic (unless ventilated), often leading to prehospital encounters.
Also called "Lou Gehrig's disease" and responsible for Stephen Hawking's disability.

Multiple Sclerosis (MS)

Steady, progressive, and irreversible degeneration of the myelin sheath primarily in the CNS.
The most frequent cause of permanent disability in young adults, aside from trauma, with onset predominantly in the 20-40 age group.
Though the exact cause remains unclear, it is thought to be an autoimmune disorder.
Links exist to the human leukocyte antigen (HLA) complex, which is responsible for numerous immune functions.
MS attacks or flare-ups can range from generalised weakness and paralysis to balance issues, paraesthesia (unusual sensations), and vision problems.

Myasthenia Gravis

Chronic autoimmune disorder characterised by the destruction of nicotinic acetylcholine receptors at the postsynaptic neuromuscular junction.
This destroys communication between nerves and the muscles they innervate.
Results in weakness of voluntary skeletal muscles, particularly those controlling the eyes, mouth, and limbs.
Symptoms include episodic muscle weakness and easy fatigability, worsening with activity and decreasing with rest.
Eye weakness is very common and often the first sign.
A myasthenic crisis occurs when respiratory muscles are affected, leading to hypopnea or apnea.

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Description

Test your knowledge on the glossopharyngeal and vagus nerves, their functions, and assessment techniques. This quiz explores sensory and motor roles as well as clinical implications. Perfect for students of anatomy or medical professionals.