Cranial Nerves PDF

## 12 Cranial Nerves | Nerve | Type | Function | Problem | |---|---|---|---| | I. Olfactory | Sensory | Smell | Anosmia (absence of smell) | | II. Optic | Sensory | Vision | Bluring of vision / Blindness | | III. Oculomotor | Motor | Eye movement | Anisocoria (unequal pupil) | | IV. Trochlear | Mot...

## 12 Cranial Nerves | Nerve | Type | Function | Problem | |---|---|---|---| | I. Olfactory | Sensory | Smell | Anosmia (absence of smell) | | II. Optic | Sensory | Vision | Bluring of vision / Blindness | | III. Oculomotor | Motor | Eye movement | Anisocoria (unequal pupil) | | IV. Trochlear | Motor | Eye movement | Smallest CN | | V. Trigeminal | Both | Maxillary (for sensation of pain & oral cavity); Opthalmic (for corneal reflex, nerve blink means Trigeminal is intact); Mandible (for chewing) | Largest CN | | VI. Abducens | Motor | Eye movement | | | VII. Facial | Both | Facial expression & taste (anterior 2/3) | | | VIII. Acoustic/Auditory | Sensory | Hearing | Hearing loss, tinnitus, vertigo | | IX. Glossopharyngeal | Both | Taste (posterior 1/3) & gag reflex | | | X. Vagus | Both | Gag reflex, PNS activation | Dysphagia, absent gag reflex | | XI. Spinal Accessory | Motor | Neck & shoulder movement | Unable to move shoulder / head | | XII. Hypoglossal | Motor | Tongue movement | Tongue deviation, dysarthria (causes slurred or slow speech altering muscles for speech) | ## 12 Cranial Nerves Summary - The **Olfactory Nerve (I)** is responsible for the sense of smell and its dysfunction results in anosmia. - The **Optic Nerve (II)** is responsible for vision, and its dysfunction can cause blurring of vision or blindness. - The **Oculomotor Nerve (III)** controls eye movement and pupillary constriction, leading to anisocoria if damaged. - The **Trochlear Nerve (IV)** is the smallest cranial nerve and controls eye movement. - The **Trigeminal Nerve (V)** is the largest cranial nerve and is responsible for sensation in the face, pain and oral cavity, corneal reflex, and chewing. - The **Abducens Nerve (VI)** controls eye movement. - The **Facial Nerve (VII)** controls facial expression, taste, and tears. - The **Vestibulocochlear Nerve (VIII)** is responsible for hearing and balance. - The **Glossopharyngeal Nerve (IX)** controls taste and swallowing. - The **Vagus Nerve (X)** controls the heart, lungs, and digestive system, and its dysfunction can cause dysphagia and absent gag reflex. - The **Spinal Accessory Nerve (XI)** controls neck and shoulder movement. - The **Hypoglossal Nerve (XII)** controls tongue movement and speech. ## Test Taking Strategies The client diagnosed with mild concussion is being discharged from the emergency department. Which discharge instruction should the nurse teach the client's significant other? - **a. Awake the client every two hours.** - **b. Monitor for increased intracranial pressure (ICP).** - **c. Observe frequently for hypervigilance** - **d. Offer the client food every three to four hours** ## Level of Spinal Nerves - **Breakfast at 8**: Controls diaphragm, chest wall muscles shoulders, arms - **Lunch at 12**: Controls upper body, GI fx - **Dinner at 5**: Controls lower body, bowel & bladder - **MS at 1**: Total 31 spinal nerves ## Nervous System - **Central Nervous System**: Brain & Spinal Cord - **Peripheral Nervous System**: Cranial & Spinal nerves - **Autonomic Nervous System**: Sympathetic & Parasympathetic ## Sympathetic vs Parasympathetic Nervous System | Sympathetic Nervous System | Parasympathetic Nervous System | |---|---| | **Fight or Flight Response** | **Rest & Digest Response** | | Catecholamine release from adrenal medulla | Acetylcholine release | | Anticholinergic / Adrenergic | Cholinergic response / vagal | | **↑** body activities except GIT & bladder | **↑** all bodily activities, except GIT & bladder | | **↓** blood flow in brain | **↑** blood flow in brain | | **↓** blood flow to GIT | **↑** blood flow to GIT | | **↑** heart rate and contractility | **↓** heart rate and contractility | | **↑** blood pressure | **↓** blood pressure | | **Dilate pupils** | **Constrict pupils** | | **Bronchodilation**| **Bronchoconstriction** | | **↓** salivation | **↑** salivation | | **↓** digestion | **↑** digestion | | **↓** urination | **↑** urination | | **↑** glucose release | **↓** glucose release | | **Inhibit bladder emptying** | **Promote emptying bladder** | | **Stimulate ejaculation** | **Promote erection**| | **Relax airways** | **Constrict airways** | | **Release of epinephrine and norepinephrine** | **Vagal response** | ## Increased Intracranial Pressure (ICP) - **Increased pressure in the skull due to an increase in one of the intracranial components.** - **Predisposing factors**: stroke (hemorrhagic stroke), tumor, inflammation (meningitis, encephalitis), trauma ## Cerebral Perfusion Pressure (CPP) - **Pressure that is needed to make sure the brain receives the right amount of blood.** - **Normal CPP**: 40-100 mmHg - **Normal MAP**: 70-100mmHg ## Cerebral Perfusion Pressure Calculation **CPP = MAP - ICP** - **MAP (Mean Arterial Pressure) = SBP + (DBP x 2)/3** ## ICP - **Normal ICP**: 0-15 mmHg - **Early Signs**: Blurred vision, visual acuity, diplopia, change in LOC, restlessness to confusion, drowsiness, lethargy, pupillary changes, eye movement problem, hemiparesis, hemiplegia, headache ## Late Signs: - **BP**: increased systolic and decreased diastolic - **Wide Pulse Pressure**: difference between systolic and diastolic (normal is 40, >60 is considered wide) - **Respiratory Rate**: irregular, Cheyne-Stokes hyperpnia (period of breathing followed by apnea) - **Temperature**: altered (may be high or low) ## Signs of Meningitis - **Kernig's Sign**: Patient supine with hip flexed 90°, knee cannot be fully extended. - **Brudzinski's Neck Sign**: Neck rigidity, passive flexion of neck causes flexion of both legs and thighs. ## Cerebral Hemorrhage - **Ischemic Stroke**: Partial or complete disruption of brain's blood supply due to thrombosis, embolism, or hemorrhage. - **Common Arteries**: Middle Cerebral Artery (MCA), Internal Carotid Artery (ICA) - **Transient Ischemic Attacks**: warning sign of impending stroke - **Hemorrhagic Stroke**: Hemorrhage, compartment syndrome (compression of nerves/arteries) - **Signs**: Headache, disorientation, confusion, decreased LOC ## Cerebral Embolism - **Embolic stroke**: Dislodged clot that travels to the brain. - **Signs**: Sudden onset of chest pain, syncope, headache, disorientation, confusion, decreased LOC ## Treatment for Cerebral Stroke - **CT scan**: Determines the type of stroke - **Cerebral Arteriography**: Reveals the site and extent of the occlusion - **MRI**: Shows damage to brain tissue. - **Carotid UIZ**: Show plaque and blood flow of carotid arteries. - **Endarterectomy**: Removal of plaque from carotid arteries. - **Echocardiogram**: Finds clot source in the heart. ## Seizures - **Abnormal sudden, excessive discharge of electricity in cerebral cortex.** - **Types** - **Focal Seizures**: Limited to one part of the brain, may only involve aura - **Generalized Seizures**: Involve the whole brain, may lead to loss of consciousness - **Febrile Seizures**: Most common in children - **Status Epilepticus**: Continuous seizure activity for at least 5 minutes or more. - **Priority**: Airway, prevent aspiration, coma, and death - **Treatment**: Diazepam, Dilantin, Thiamine - **Dx Tests**: CT scan (brain lesion), EEG (hyperactive brain waves) ## Multiple Sclerosis - **Chronic autoimmune disease that destroys myelin shealth of neurones in CNS** - **Symptoms**: Charcot's Triad (optic nerve: blurring of vision, diplopia, scotomas, nystagmus; Brainstem: dysarthria, cranial nerve 4 affected; Motor pathways: tremors, ataxia, muscle weakness & spasms - **Other possible symptoms**: - Paresthesia, sensory loss, incontinence, impaired sexual ability, cognition issues, mood swings - **Dx Tests**: CSF analysis (CSF protein, oligoclonal bands), MRI (demyelination) - **Treatment**: - supportive/palliative: manage symptoms, prevent complications, avoid overheating - acute exacerbation: corticosteroids (prednisone, dexamethasone), corticotropin (ACTH). - chronic: immunosupressants (beta-interferon) ## Alzheimer's Disease - **Progressive, degenerative brain dse** - **Common in women** - **Cause:** Deficiency of Somatostatin, Acetylcholine, Norepinephrine, and Substance P - **Symptoms:** Memory loss, amnesia, agnosia, apraxia, aphasia, ideation apraxia, receptive aphasia - **Dx Tests**: CT scan, autopsy - **Treatment**: Supportive/palliative, Donepezil (Aricept) ## Parkinson's Disease - **Progressive, degenerative dse** - **Common in older adults** - **Cause:** Depletion of dopamine - **Symptoms**: Resting tremor, rigidity, bradykinesia, postural instability, akinesia, mask-like facies, speech and swallowing difficulties, - **Treatment**: - Supportive/palliative: Maintain siderails, turn pt Q2H, assist in passive ROM, increase fluid intake, high fiber diet, safety precautions, assist in ambulation, assist in surgery (Deep Brain Stimulation) - Medications: Levodopa (L-Dopa) with Carbidopa, Amantadine, Artane, anticholinergics, iron supplement, vitamin C - Important to note that anti-Parkinsonian medication should be taken before meals to increase absorption. - **Note** The disease progressively worsens. ## Myasthenia Gravis - **Chronic autoimmune disorder** - **Involves impulse transmission at the neuromuscular junction** - **Affects voluntary muscles** - **More common in women** - **Cause**: Idiopathic - **Symptoms**: Ptosis, diplopia, mask-like facies, dysarthria, dysphagia, hoarseness, respiratory muscle weakness, leg weakness, fatigue - **Dx Test**: Tensilon Test (Edrophonium chloride) - **Crisis**: Two types of crisis: - **Myasthenic Crisis**: Caused by undermedication, stress, infection. - **Cholinergic Crisis**: Caused by overmedication. - **Treatment**: - Supportive/palliative: Airway management, aspiration prevention, immobility, side rails, passive ROM exercises, NGT feeding, plasmapheresis, thymectomy. - Medications: - **Cholinergics**: (Pyridostigmine, Neostigmine) - **Corticosteroids**: (Prednisone, dexamethasone) - **Immunosuppressants**: (Azathioprine, Methotrexate) ## Guillain-Barré Syndrome - **Acute, ascending symmetrical paralysis** - **Caused by demyelination** - **Affects men and women equally** - **Cause**: Idiopathic - **Recovery is possible** - **Symptoms**: Clumsiness, decreased deep tendon reflexes, paresthesia, difficulty breathing, dysphagia, ANS changes (alternate hypertension to hypotension, urinary incontinence, constipation) - **Treatment**: - Supportive/palliative: Airway management, monitor pulmonary function test, monitor VS, I&O, neuro check, ECG, maintain siderails, prevent complications of immobility, assist in passive ROM exercises, NGT feeding, plasmapheresis. - **Medications**: - **Corticosteroids**: Prednisone, dexamethasone - **IV Immunoglobulins**: Amiodarone, Lidocaine, Bretylium