Cranial Nerve Exam (Sabounchi) PDF, January 22, 2025

CRANIAL NERVE EXAM Shabnam Seyedzadeh Sabounchi, DDS, PhD Associate Professor, Orofacial Pain Department of Oral Pathology, Oral Medicine and Maxillofacial Surgery Temple University Kornberg School of Dentistry  Learning Objectives  Will be able to  Define what is accurate dia...

CRANIAL NERVE EXAM Shabnam Seyedzadeh Sabounchi, DDS, PhD Associate Professor, Orofacial Pain Department of Oral Pathology, Oral Medicine and Maxillofacial Surgery Temple University Kornberg School of Dentistry  Learning Objectives  Will be able to  Define what is accurate diagnosis  Review the anatomy and function of the 12 cranial nerves  Describe cranial nerve exam  Describe disorders involving the 12 cranial nerves  Define Quantitate Sensory Testing (QST) and applications in evaluating patients with nerve disorders Reference: De Leeuw R, Klasser G, editors. Orofacial Pain: Guidelines for Assessment, Diagnosis, and Management (AAOP The American Academy of Orofacial Pain), 7th Edition. 2023. INTRODUCTION A Correct Diagnosis in Health Care Most important step of patient management is obtaining an accurate history This can eliminate the expense of additional diagnostic procedures Thorough observation, recording, and analysis of findings  Orofacial Pain Frequently involves neuropathic disorders The cranial nerve examination is a necessary portion of the examination: – Necessary to evaluate physiologic and anatomical implications of disturbed function of the cranial nerves – Important to a clinical diagnosis [Neuropathic pain is now defined by the International Association for the Study of Pain (IASP) as ‘pain caused by a lesion or disease of the somatosensory nervous system’. ] de Leeuw and Klasser. Orofacial Pain: Guidelines for Assessment, Diagnosis and Management, 7th Edition 2023.  Neurologic Screening  Cranial nerve dysfunction may manifest as changes in either motor or sensory function.  Abnormal movement of muscles stimulated by one of the cranial nerves can indicate pathosis along the motor pathways.  A patient reporting sensory alterations may be tested for anesthesia, paresthesia, dysesthesia, allodynia, and hyperalgesia. de Leeuw and Klasser. Orofacial Pain: Guidelines for Assessment, Diagnosis and Management, 7th Edition 2023.  Neurologic Screening  Anesthesia: Pain in an area or region which is anesthetic.  Paresthesia: An abnormal sensation, whether spontaneous or evoked.  Dysesthesia: An unpleasant abnormal sensation, whether spontaneous or evoked. Note: Compare with pain and with paresthesia. Special cases of dysesthesia include hyperalgesia and allodynia. A dysesthesia should always be unpleasant, and a paresthesia should not be unpleasant  Allodynia: Pain due to a stimulus that does not normally provoke pain.  Hyperalgesia: Increased pain from a stimulus that normally provokes pain. "Part III: Pain Terms, A Current List with Definitions and Notes on Usage" (pp 209-214) Classification of Chronic Pain, Second Edition, IASP Task Force on Taxonomy, edited by H. Merskey and N. Bogduk, IASP Press, Seattle, ©1994.https://www.iasp-pain.org/resources/terminology/.  Neurologic Screening  Allodynia: Lowered threshold - Stimulus and response mode differ  Hyperalgesia: Increased response - Stimulus and response mode are the same  Hypoalgesia: Raised threshold: lowered response - Stimulus and response mode are the same "Part III: Pain Terms, A Current List with Definitions and Notes on Usage" (pp 209-214) Classification of Chronic Pain, Second Edition, IASP Task Force on Taxonomy, edited by H. Merskey and N. Bogduk, IASP Press, Seattle, ©1994.https://www.iasp-pain.org/resources/terminology/. Cranial Nerves 12 pairs of cranial nerves Provide sensory and motor innervation for the head and neck region Carry 6 distinct modalities 3 sensory 3 motor Cranial Nerves: Sensory General sensory nerves Touch, pain, temperature, pressure, vibration and proprioceptive sensations Visceral sensory nerves Sensory input, except pain from the viscera Special sensory nerves Smell, vision, taste, hearing and balance Cranial Nerves: Motor Somatic motor nerves Innervate the voluntary muscles that develop from the somites Branchial motor nerves Innervate the voluntary muscles that develop from the branchial arches Parasympathetic (visceral) motor nerves Innervate the viscera, including the glands, mucosae and all involuntary smooth muscle Key Message: A working knowledge of the anatomy and function of cranial nerves is needed to: Interpret clinical findings Accurately diagnose Treat or refer patients to an appropriate medical provider CRANIAL NERVES: EXAMINATION Examination Consciousness Depends upon interaction between intact cerebral hemispheres, and the upper brain stem, where activating mechanisms reside Extensive disease of the cerebral cortex or lesions of the brain stem may impair consciousness Mental status and speech Brief Cranial Nerve Exam Videos https://youtu.be/t5dolQ-Pzdw https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source =web&cd=&cad=rja&uact=8&ved=2ahUKEwjq7vHG3oWG AxW9JkQIHYj6ApUQtwJ6BAgWEAI&url=https%3A%2F%2 Fwww.youtube.com%2Fwatch%3Fv%3DvU8-PLsdJ- w&usg=AOvVaw2b1rGHvYTG68aIonCZ- 9cz&opi=89978449 Cranial Nerve Examination CN I: Olfactory Sense of smell Not usually checked unless there is a specific complaint Check that nasal passages are patent, and check each side individually Use non-irritating familiar stimulus Coffee, chocolate CN I: Olfactory Clinical Considerations – CN I Anosmia Loss of sense of smell Temporary loss of smell results most commonly, from swelling and congestion of the nasal mucosa due to the common cold or allergic rhinitis Permanent unilateral or bilateral anosmia can result from fractures of the cribriform plate, olfactory groove meningiomas and tumors of the frontal lobe CN I: Olfactory Clinical Considerations – CN I Ipsilateral loss of olfaction [anosmia] A-P skull fracture parallel to the sagittal suture Denervation of the cribriform plate following head trauma Possible CSF leak into nasal cavity Frontal lobe masses Tumor or abscess Compression of olfactory tract Lesion of primary cortical olfactory area in the temporal lobe » Olfactory hallucinations » Phantom smell  CN II: Optic Special sensory for vision Examination of the optic nerve involves four procedures: Measurement of visual acuity Testing of visual fields Testing of the pupillary light reflex Visualization of the fundus (Not done in dental practices) “The fundus of the eye is the inside, back surface of the eye. Composed of the retina, macula, optic disc, fovea and blood vessels.” CN II: Optic CN II: Optic Testing of the pupillary light reflex Pupillary light reflex relies on the integrity of both CN II (sensory pathway) and the parasympathetic nerve fibers that travel with CN III (motor pathway) Beam of light is shone directly on one pupil If both sensory and motor pathways are intact: Ipsilateral pupil constricts (direct response) Contralateral pupil should also constrict (indirect/consensual response) CN II: Optic CN III, IV and VI Eyelid position Elevation of eyelid results from activation of the levator palpebrae superioris Damage to CN III will result in ptosis Pupillary response to light Accommodation Allows the eye to focus on near objects Convergence and pupillary constriction of both eyes Extraocular eye movements CN III: Accommodation Abnormalities Blind eye Oculomotor nerve palsy Ptosis, mydriasis, “down and out” gaze Anisocoria Unequal size of the eyes' pupils Abnormalities Dilated Pupils Trauma Cocaine Small Fixed Pupils Opiates Nystagmus Amphetamines CN V: Trigeminal Sensory Component Discriminative touch, pain, temperature Simple touch Touch skin with sharp end of a pointed object and ask patient what he/she feels Temperature: hold warm or cool objects against the skin Simple touch: lightly touch skin with cotton wisp Check bilaterally for the presence of each modality in the forehead (V1), cheeks (V2) and jaw (V3) Determine if both sides of the face are equally sensitive Corneal reflex: observe whether patient blinks in response to a light touch with a wisp of cotton on the cornea CN V: Motor Component CN VII: Facial Facial Nerve supplies muscles of facial expression Raise eyebrows Frown Close eyes tightly and you try to open them Smile Show teeth Puff out cheeks Types of Facial Paralysis Upper motor neuron lesions Cortical tumors, infarcts (stroke) and abscesses affecting upper motor neuron cell bodies in the motor cortex, or their axons that project to the facial nucleus Loss of voluntary control of the lower muscles of facial expression contralateral to the lesion The frontalis muscle continues to function because it receives input from the ipsilateral hemisphere Types of Facial Paralysis Lower motor neuron lesions Lesions resulting from damage to the facial nucleus or its axons anywhere along the course of the nerve after it leaves the nucleus Complete paralysis of the facial nerve ipsilaterally Bell’s palsy Meningiomas Meningitis Acoustic neuromas Infarct involving the pontine branches of basilar artery CN VIII: Vestibulocochlear Special sensory for hearing and balance Balance Walking heel to toe along a straight line Hearing Patient covers one ear and examiner whispers in other ear Conductive hearing loss Obstruction in transmission of sound from the air to the cochlear Wax, ear infection, damage to tympanic membrane Sensorineural hearing loss Damage to the auditory pathway This will result in hearing loss on the one side CN IX: Glossopharyngeal CN X: Vagus Both supply fibers to the back of the throat CN X innervates intrinsic muscles of the larynx Listen to voice for any hoarseness Check oropharynx and have patient say “Ah”. The soft palate should move up symmetrically with the uvula staying in the midline Check the gag reflex on both sides CN XI: Spinal Accessory Inspect trapezius for any atrophy, symmetry, fasciculation Test trapezius for strength by asking patient to shrug shoulders against your holding against them Test the sternocleidomastoid by having patient turn head to side and push against your hand CN XII: Hypoglossal Have patient stick tongue straight out, then move side to side If it deviates it will deviate towards paralyzed/weak side de Leeuw and Klasser. Orofacial Pain: Guidelines for Assessment, Diagnosis and Management, 7th Edition 2023. Quantitative Sensory Testing (QST) QST is established as a protocol to examine: thermal and mechanical sensory function, offers insight on potential mechanisms contributing to an individual’s experience of pain, by assessing their perceived response to standardized delivery of stimuli. Quantitative Sensory Testing (QST) - Physiopedia.pdf  Quantitative Sensory Testing (QST) Conditions for which QST can be useful include (1,2): Neuropathic pain, Polyneuropathy (diabetic, HIV-related, chemotherapy-related), Postherpetic neuralgia, Complex regional pain syndrome (CRPS), Chronic low back pain, Knee osteoarthritis. 1. Weaver KR, et al. Quantitative sensory testing across chronic pain conditions and use in special populations. Frontiers in Pain Research. 2022 Jan 28;2:779068. 2. Mucke M, et al. Quantitative sensory testing (QST). English version. Schmerz. 2016;35:153-60. CRANIAL NERVES: DYSFUNCTION  Local Anesthesia Complications Neuralgia (Facial Pain) Infarcts/ Cerebrovascular Accident/ Stroke Infections Bacterial/odontogenic Viral: herpes simplex and herpes zoster Inflammatory Conditions Toxins (Drugs) Trauma Tumors Bell’s Palsy Idiopathic facial paralysis Most common cause of unilateral facial paralysis Compression of the nerve as it passes through the facial canal in the petrous portion of the temporal bone Men = Women Signs and symptoms are determined by the branches of the facial nerve that are affected Motor: acute onset of unilateral weakness Sensory: impairment of taste and hyperacusia Secretory: reduction of salivary gland function 80-85% recover within 3 months Treatment: corticosteroids, eye care, antivirals, surgery Bell’s Palsy https://news.yahoo.com/c-tv-reporter-loses-her-smile-bells-palsy-164432652--abc-news-wellness.html Classic Ramsay Hunt Syndrome A complication of varicella zoster virus infection Reactivation of herpes zoster in the geniculate ganglion Triad of Clinical Features Patients typically present with paroxysmal pain deep within the ear Vesicular rash of ear or mouth Ipsilateral lower motor neuron facial palsy (CN VII) Other Cranial Nerve Findings Vertigo and ipsilateral hearing loss (CN VIII) Herpes Zoster Trigeminal Neuralgia Painful condition that affects the face unilaterally in the distribution of one or more divisions of the trigeminal nerve Average age of onset: approx. 50 years Trigeminal Neuralgia Clinical Presentation Pain Unilateral Localization In distribution of V2, V3 and less likely V1 Quality Severe, electric shock-like, stabbing pain Duration Brief (Paroxysms) Seconds to 2 minutes Triggers Non-painful stimuli Washing face, shaving, touching tooth, brushing teeth Frequency Several per day Associated No neurologic deficits symptoms Trigeminal Neuralgia Pathogenesis Demyelinating compression of the trigeminal nerve Compression of the nerve root close to its entry into the pons by overlying blood vessels Superior cerebellar artery Spontaneous nerve firing and cross-talk among adjacent fibers Symptomatic Trigeminal Neuralgia 15% of cases Invasive tumors Neurological symptoms Vascular anomalies Multiple sclerosis Bilateral symptoms Young age Associated symptoms: diplopia, loss of vision, muscle weakness Cavernous Sinus Syndrome Rare condition characterized by: Ophthalmoplegia: paralysis or weakness of the eye muscles Proptosis Ocular and conjunctival congestion Trigeminal sensory loss Horner’s syndrome Results from pathologic involvement of the cranial nerves passing through the cavernous sinus Infectious or noninfectious inflammatory, vascular, traumatic, and neoplastic processes are the principal causes Serious odontogenic infections Contents of Cavernous Sinus Horner’s Syndrome Oculosympathetic paresis Interruption of the sympathetic nerve supply to the eye Classic triad Miosis Partial ptosis Loss of hemifacial sweating Clinical presentation depends on the level of the lesion Prognosis depends on the underlying cause Horner’s Syndrome Superior Orbital Fissure Syndrome Rare neurological disorder resulting from involvement of cranial nerves that pass through the superior orbital fissure, which runs lateral, anterior and superior from the apex of the orbit Craniomaxillofacial trauma: most common cause (zygomatic and orbital floor fractures) Other causes: neoplasms, syphilis, sinusitis, herpes zoster etc Superior Orbital Fissure Syndrome Rare neurological disorder resulting from involvement of cranial nerves that pass through the superior orbital fissure, which runs lateral, anterior and superior from the apex of the orbit Symptoms: Eyelid ptosis Globe proptosis (forward protrusion of the globe with respect to the orbit) Absent/decreased extraocular movements CN III, IV, VI Ophthalmic division V1 anesthesia TAKE HOME MESSAGES A working knowledge of the anatomy and function of cranial nerves is needed to: Interpret clinical findings Accurately diagnose Treat or refer patients to an appropriate medical provider