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Chapter t3 Cranral Nerve Palsy Update Christopher S. Wolfe, O.D., F.A.A.O. Updated 2016 by: Philip Roels, O.D., F.A.A,O 177 CHAPTER 13. CRANIAL NERVE PALSY UPDATE 178 13,1 Oculomotor Nerve Palsy o The oculomotor nucleus in the midbrain consists of subnuclei responsible for inner',?tion of the individual extraocular muscles, the levator palpebrae, and the iris sphincter muscle. The third nerve leaves the midbrair and enters the subarachnoid space before entering the cavernous sinus It then splits into superior and inferior branches when entering the orbit l,hrough l,he superior orbihal fissurc. - The superior division of the oculomotor nerve supplies the ipsilateral levator and the contralateral superior rectus. - The inferior division of the oculomotor nerve innervates the ipsilateral medial rectus, inferior rectus, inferior oblique, and the iris sphincter muscle. . Common causes of an oculomoto! nerve pa,lsy iDclude an aneurysm to the posterior communicating artery, tumor, trauma, pituitary apoplexy, orbital inflammation or masses, herpes zoster, Ieukemia, and uncal herniation. . It occurs most often in patients over age 50 with microvascular factors. risk Symptoms: Depending on the severity of the upper eyelid ptosis, the patierrt may or m8y not notice diplopia due to the upper eyelid blocking the visual axis of the affected cye. Patients may also conrplail of nrild or moderate pain in ischemjc lesions, or severe pain in cases of a ruptured ancrrrysm, innammatory lcsions, or pitujLary apoplexv (6). Signs: A complete palsy will have an ipsilateral ptosis with an eye tllat rs down and out. Incomplete palsy is anything less thaD a complete palsy. Exatnples include the following: . A riAht inferior oblique palsy will present with a right hypotropia in primary gaze and vertical diplopia that is y/orse on gaze up and to the left and worse with head tilt to the teft 13 1, OCULOMOTOR NERVE PALSY 179 Inferior oblique muscle entrapment ard Brown's syndrome may present with Endings sirnilar to a right inferior oblique palsy, Forced duction testing may be used to diEerentiate between these conditions. An inferior oblique palsy is chara.te zed by a negative forced duction test (the eye will mo\re when forced), while Bro{,'n's s}.ndrome and an inferior oblique muscle entrapment are characterized by a positive forced duction t€st (the eye will not move when forced). o Right medial rectus palsy will present with horizontal diplopia that is worse on left gaze, and a negative forced duction test. . RiBht supetior rectus palsy will present with right hypotropia in prima.ry gaze that is worse on gaze right and head tilt to the right, as well as a negative forced ductio[ test. . Superior division palsy is chara.terized by significant ptosis and limited ability to look up, a.s this division of CN 3 contrcls both the superior rectus and the le\Btor palpebra€ muscle. o Inferior division palsy will present with poor a.dduction a.nd limited ability to look down, a.s this division of CN 3 inrlenBte6 the medial rectus, inferior rectus, and the inferior oblique- I\eatment will depend on the extent of EOM and pupil involvement . If the palsy is incomplete or if the pupil is involved (dilated), an imme. diate MRI/MRA is indicated. . If the palsy is complete, the pupil is NOT involved, the patient is over the age of 40 with known \,rscula.r disease (e.g., diabetes rnellitus, hypertension, smoking), there are no other neurological abnormalities, and there ale no new s],.mptorna on subsequent exams, the palsy is considered ischemic in nature. Tlestment includes: - Flesnel prism or petching os symptoms dictate Check blood plessure, blood sugar, and hemoglobin A1c - Abefiant regeneration never occurs in ischemic CN 3 palsies. Monitor for resolution; if there is no resolution by 3 months, an MRI/MRA is indicated. . Third nerve palsies that are NOT isolated, and/or are accoopa.ried by othe! neurologic sitns or symptoms require prompt neuroimaging with MRI/MRA. . Patients older tha.n 55 years of age should be evaluated for symptorrrc ard signs of giant cell arteritis, including ordering a CBC, er).throclte sedimentation rate (ESR), and C reactive protein (CRP). o An orbital CT scan is indicsted if orbital dis€a.se is suspected as the cause of a third nerve palsy due to proptoois and/or resistance of the globe to retropulsion. CHAPTER 13, CRANIAL NERVE PALSY UPDATE 180 13.2 Tlochlear Nerve . Palsy CN 4leaves the midbrain dorsally and then decussates to the contralateral side of the brainstem; thus, the right superior oblique is innervated by the right CN 4, with its nucleus on the left side of the brainstern. Because CN 4 has the lontest course, it is most susceptible to trauma. Symptoms: vertical diplopia without ptosis Signs: head tilt and turn away from the involved eye, and limited depression on adduction 1. Congenital CN 4 palsy: . Long history of head tilt (refer to old pictures) o F\ller face on the opposite side of the head paretic muscle) tilt (sarne side &s the . No torsional diplopia complaints, and may not see a torsional conrponent with Ma.ddox rod . Large yertical vergence ranges: sional amplitude > 3 prism diopters of vertical fu- 2. Acquired CN 4 palsy (trauma, vascular, iatrogenic (e.g., sinus surgery, orbital surgery), or tumor): o No facial asymmetry . . Acute ons€t Torcional diplopia - perform a double Maddox rod test if a bilateral CN 4 palsy is suspected 3. Park's Thrcc Stcp can be uscful lor confirnring a CN 4 palsy, :s only a single muscle is responsible for a yertical deviation. The test involves the following questions (2): a) Which . eye is highest in the primary position of gaze? The afiected muscle could be the inferior-acting muscles (inferior rectus or superior oblique) in the hyper eye OR the superior-acting muscles (superior rectus or inlerior oblique) in the h)?o eye. b) Is the hyper worse when the patient looks in left or irr right gaze? c) Is the hyper worse when the patient tilts his head to the left or to the right? ]3.3. ABDUCENS NERVE PALSY 181 try to rninimize the eflects of a superior oblique palsy by tilting their head away from the afrected side. One of the actions Patients will of the superior oblique is incyclotorsion; by tilting their head away fronr the aflected side, patients minimize incyclotorsion of the affected eye, resulting in a decrease in diplopia. o Che& blood pressure, blood sugar (BS), and hemo8lobin AIC if miclovascular disease is suspected. . An orbital CT is indicated if orbital disease is suspected due to proptosis snd/or resistence to retropulsion. . Order er,'throc)'te sedimentation rate (ESR), C reactive protein (CRP), and platelets if GCA is suspected. . If the patient has large vertical fi$ional vergence ranges, or old pictures show a head turn, consider prescribing vertical prism based on the asso ciated phoria findings. o If the CN 4 palsy is progressive, other neurological findings are present, the patient is younger than 40 without a history of head trauma, or the patient is 4G55 years of age with no microlascular risk factors, consider neurcimaging. 13,3 . Abducens Nerve Palsy CN 6 fibers leave the nucleus in the pons by Lraversing between the pons and the medulla before making a tight bend over the petrous ridge of the temporal bon6 to enter the cavernous sinus (3). Within the cavernous sinus, CN 6 trsvels near the lateral wall of the internal carotid artery. Lesions along the course of CN 6 can lead to tnpaired function. . Common causes of CN 6 palsy include: - Microvascular: patients with undiagnosed or uncontrolled DM or HTN Ttmors or pseudotumor cerebri * An increase in intracranial pressure will ptrch CN 6 down onto the petrous portion of the temporal bone, resulting in decreosed innervation of the lateral rectus (12). ,r A tumor involving the ca\.€rnous sinus or brainstem rnay present with Ilorncr's syndrome in addition to an abduction dcficit CHAPTER 13. CR,4NIAL NERVE PALSY UPDATE 182 - tatrma - lnternal carotid adery sreurysm Symptoms: horizontal diplopia Signs: limited ABduction . If patients . . Orde! an ESR, CRP, and platelets if GCA is suspected. present with symptoms or signs of increased intracranial pressure (e,g., postural headache, papilledema, neurological symptonls), or llvith multiple cranial nerve involvement, irrrnediate neulo-imaging with an MRI/MRA is vrarranted. Order an RPR, FTA-ABS, and Lyme titer if syphilis or Lyme disease is suspected. . If patients have a history of micro!"scular disease, communicate with their PCP to ensure adequate control of blood sugar, blood pressure, or any other relerant measures. If DM and HTN are controlled, and the CN VI palsy does not resolve within 3 months, consider neuro-ilnaging. . Consider Fresnel prism or occlusion for temporary relief of diplopia Once the ocular deviation has stabilized, consider ground-in prism in spectacle Ienses. 13.4 Facial Nerve Palsy(CN VII) o The faciol nerve is lesponsible for voluntary motor inneE€tion to the muscles of facial expression and eyelid closure, as well as involuntary motor innervation to the inner ear (stapedius muscle), and parasympathetic supply to the facial glands (including the lacrimal gland) The facial nerve also co.rries taste sensations from the anterior 2/3 of the tongue. . CN 7 travels near CN 6 and CN 8. If a patient presents with a palsy of one of those crarial nerves, check the aations of the other 2 cratial nerves to determine whether all three axe involved . The following is a description of the neurological path of CN 7: - Movements are initiated in the precentral motor cortex irr the lob€ ( l1). frontal Fibers descend within the corticobulbar tract to the nuclei of CN 7 in the pons ( 11). 13.4. FACIAL NERVE PALSY(CN VII) - - 183 Fibers leave the nucleus by arching arouDd the abducens nucleus; any nuclear lesion of CN 6 could also afrect CN 7. Fibers then travel with CN 8 through the temporal bone (12). Within the temporal bone, the greater petrosal nerve breaks away, carrying parasympathetic innenation to the lacrimal gland. As the fibers leave the temporal bone, CN 7 departs from CN 8 and enters the fallopian ca.nal. Withir tle canal, CN 7 Sives ofl a motor trranch to the stapedius rnuscle (to dampen sound) and the chorda tyrnpari nerue (carries taste from the anterior two-thirds of the tongue and parasympathetic 6bers to the submandibular and sublingual glands). CN 7 leaves the fallopian canal and exits the skull via the stylom&stoid foramen, then divides irrto terrninal branches within the parotid gland. These branches inner%te the muscles of facial expression; they do not inneF'ate the parotid gland (receives innen?tion lrom cN e). Symptoms: Iack of lower and/or upper facial expression, reduction in taste, and decreased Iacrimation and sali%tion Signs: exposure keratitis, incomplete lid closure, facial asyrnmetry . A supranuclear lesion results in impaired inneruation to the Iower facc on the contralateral sidc. The contralatcral fibers that arc rG sponsible for eyelid closure and wrinkling of the forehead a.re spared; therefore, stroke patients should be able to wrinkle their forehead and lirrnly close their eyes. Damage on one side of the l:rain contributes to contralateral muscle weakness of the lower face, which can manifest as mouth drooping. . A lower motor neuron lesion (i.e., Bell's palsy) results in impaired iunervation to the entire side of the face on the ipsilateral side. Paticnts will not bc ablc to lirmly closc thcir eye and Lhcir mouths will droop on the affected side. A lower motor neuron lesion can result in paralltic lagophthalmos, the most common form of lagophthalmos ( 1). Bell's Palsy will completely resolve without treatment in 70-80% of cases (8). o If Bell's palsy is present without sny other craoial nerve defects or other neurological symptoms, and without a history of facial spasm, teuroimaging is not necessary (8). . If the patient presents within (l 10 days of onset, consider oral prednisone mg/kg of body weight, dosed in the morning) for 7-10 days, with a short taper after 10 days (4). . Consider sdding an oral antiviral (800 mg acyclovir 5X/day, 500 rrrg famciclovir TID, or 1,000 mg relacyclovir TID) for 7-10 days if a herpetic infection is suspected (4). CHAP'TER 13, CRANIAL NERVE PALSY UPDATE 184 . Bell'B palsy may be the initial s],mptom of a more serious underlying disease. Therefore, if the palsy wonens or do€s not improve within 6 weeks, neuro-imaging is indicated (11). 1. How often is an isolat€d cranial nerve palsy due to an etiology other than microvascular disease? . . A prospectile observation case series of 109 patients older than age 50 was performed to estimate the proportion of patients with isG lated third, fourth, or sixth cranial nerve palsies of presumed microaascular origin veNus other caused (15): - 62 patients had cranial nerve 6 palsy - 25 patients had cranial nerve 4 palsy - 22 patients had cra al nerve 3 palsy 18 patients had a cronial nerve palsy caused by an etiolo6/ other than presumed microvascular ischemia (e.g., midbrain infarction, neopla.srns, iDflarnmation, pituitary apoplexv, and giant cell arteritis). 2. 15 of these 18 patients had either GCA or a cranial nerve 3 palsy. The incidence of non-miclov'ascular causes for isolated fourth and sixth cranial nerve palsies \rvas 4.770 (3164). Wlat is the most common cause of a CN 4 patsy? . In a study of 190 patients with a superior oblique palsy, 72% of p8lsieg were congenital, arld 28ya werc acquired. Of the acquired CN 4 palsies, 54% were due to trauma (per history), 23% were iatrogenic, 13% were vascular, and 10% were caused by a tumor. Of the 1S0 patients with a supe or oblique palsy, only 2.8% of cases were due to a tumor (16). 3. 'What are the rnost common risk factors associated with microvasculaf cranial nerve palsies? . A study of 54 patients wa6 pelformed to investigate the risk factors ond prognoEis for ischemic cra.nial nerve 3, 4, and 7 palsies (9): - Out of microaescul$ sk factors including diabetes mellitus (DM), hypertension (HTN), hlperlipidemia, ischemic heart disease, left ventricular hlpertrophy (LVH), aad smoking, DM, HTN and hyperlipidemia were much more likely to be the u[derlying cause of the cranial nerve palsy compared to the other risk factors. - The average recovely time for patients with 2 or more risk factors was 9.0 +/- 5.1 week. - The average lecol€ry time for patients with 1 risk factor wa.9 6.1 t/- 2.2 weks. 4. Does aspirln play a role in preventing cranial nerve palsies? . A study of 100 patients that eraluated whether aspirir helped to prevent ischemic CN palsies associated with DM a.nd/or HTN found no siSnificant difference in the incidence of CN palsies in patients who took aspirin compared to those who did not (7) 13.4. FACIAL NERVE PALSY(CN Vrr) 185 5. Do oral steroids or oral antivirals improve resolution of Bell's palsy? . A study of 551 patients older than 16 yearc of age with unilateral, idiopathic facial nerve weakness (Bell's pa-lsy) seer within 72 hours after the onset of symptoms evaluated whether early treatment with oral prednisone (25 mg BID) or oral a.yclovir (400 mg 5X/day) improves the chance of recovery in Bell's palsy compared to a placebo (14). Patients were randomized into I of 4 treatment groups and were followed for I months: a) Acyclovir (400 mg 5X/day for 10 days) + placebo b) Acyclovir (400 mg SX/day for 10 days) + prednisone (25 mg BID for 10 days) Prednisone (25 mg BID for 10 days) Placebo + Placebo 3 month study results: c) d) . - . I + placebo 83% of patients who received oral predlisone demonstrated complete recovery compared to 63.6% ofpatients who do not receive oral prednisone (Absolute risk reduction (ARR) : l9-4%, Number needed to treat (NNT) : 6). 71.2% of patients taking acyclovir demonstrated complete recovery compared to 75.7% of patients who did not receive acy- clovir (not a statistically sigrifrcart difierence). 64.7% of patients who received double plaaebo demonstrated complete recovery. month study results: - 94.4% of patierlts who received ora,l prednisone demoostrated complete recovery compared to 81.6% of patients who did not - receive prednisone (ARR : 12.8%, NNT = 8). 85.4% ol patients who received acyclovir demonstrated complete recovery compared to 90.8% of patients who did not receive a.yclovir (nob a statistically significant difierence). a5.2% of patients who received double placebo demonstrated complete recovery. 6. Does the addition of valacyclovir to oral prednisone aid in the resolution of Bell's palsy? o A study of 296 patients older than 15 years of age with unilateral, idiopathic facial nerve weaftness (Bell's palsv) seen within 7 davs after the oruet of symptoms evaluated whethei treatment with oral prednisole and oral va.lacyclovir improved resolution conpared to oral prednisone alone (5). Patients were randomized into I of 2 . treatment groups and were followed untjl recovery or 6 months: a) Valacyclovir (500 mg BID for 5 days) * prednisone (60 mgld for 5 days, 30 mg/d for 3 days, 10 mg/d for 2 days) (VP) b) Placebo + prednisone (60 mg/d lor 5 days, 30 mg/d for 3 days, 10 mg/d for 2 day$ (PP) Complete recovery occurred in 96.5% of patients in the VP group compared to 89.7% of patients in the PP group (ARR = 6.8%, NNT : . 15). Patients treated with Iacyclovir within 3 days after the onset of symptoms were siSnificantly more likeLy to recover. CHAPTER 13, CRANIAL NER]/E PALSY UPDATE r86 . For patients treated 4 days or more afler the onset of symptoms, there was no significant diflerence in recovery between treatmenL SrouPs. KMK Clinicat . Pearls In patients with an isolated CN 3 palsy, have a heightened suspicion of other underlying diseases, even in the presence of microvascular disease. Consider ordcting an MRI/MRA, CBC with differential, DSR, and CRP, even when the pupil is not involved, in a patient with a complete CN 3 palsy. o A microrarular CN palsy is expected to completely resolve by 3 rnonths; neuro-imaging should be performed (or repeated) at 3 months if resolution has not occurred. Also recall that the greatpr the rumber of microvascular risk fa.tors, the longer it may take a CN palsy to resolve; it is unlikely for patients with I micro\,ascular risk factor to have a CN palsy that does rot resolve withil 2 months, so it may be prudent to consider neurGimaging in patients with presumed ischemic CN palsies at 2 months if resolution has not occurred by that tiIne. o Aspirin appears to be ineffective at preventing ischemic third, fourth, sixth, and seventh cranial nerve palsies. There are no clinical trials that have investigated whether aspirin prescribed at the initial onset of a CN palsy results in faster resolutiorr. . Acute, unilateral facial paralysis can occur from damage to the facial nerve secondary to infcctiolr, inflafiunation, compression, or trauma. T]rc diagnosis of Bell's palsy is reserved for those cases in which the precipitating event cannot be identified (i.e, idiopathic CN 7 palsy) . Patients presenting with a new onset Bell's palsy within 72 hours should be educated that there is an approximately 65% chance of complete recovery in 3 months, and an 85% chance of complete recovery in I months without treatment. . The use of oral prednisone in previous studies has been shown to increase the likelihood of complete recovery to 83% by 3 months and 94% by 9 months. . Oral prednisone should be used with caution in patients with poorly controlled diabetes mellitus or hypertension, or a comprornised imnrune system. Oral prednimne shor.rld also be avoided in patients who are pregnant o! breast-feeding. . For those patients with s complete Bell's palsy, the addition of vala- cyclovir (50O mg BID for 5 days) can signiffcantly improve the likelihood of a complete recovery by 6 months. This statistical difference was not seen if the patient was siarted onT.alacyclovir 4 days or more after the onset of symptoms. . Treating BelJ's palsy with oral acyclovir docs not significanhly improvc the likelihood of recovery, . Consider testing for herpes zoster (VZV), as it is the cause of facial paJal)sis similax to Bell's palsy in up to 870 of patients with presumed Bell's palsy (5). 13.4. FACIAL NER\E PALSY(CN VIt) . VZV faaial paralysis is often more r87 severe and has a wolse recovery rate compaxd to Bell's palsy. Due to the Iow incidence of VZV facial paralysis, the low complication rate associa,ted with treatment, and the need to quickly start treatment, patients should be treated empirically as a Bell's palsy without waiting for the results of serologic testing for VZV. . Additional testing and neuro-irnaging should be considered in patients whose Bell's palsy has a slow onset (longer than 10 days), occurs bilaterally, or is associated with other syrptonrs (13). References Ii] Bartlett J, Jaanus S. Clinical Ocular Pharmacology, sth Edition. Butterworth-Heinemann, 2008. [2] Casser L, Fingeret M, Woodcome H. Atlas of Prirnary Eyecare Procedure;, {3] Doxanas MT, Anderson RL. Clinica-l Orbit&l Anetomy. Baltimore: Williams and Wilkins, 1984; 131 [4] Goroll A, Mulley A. Primary care medicine: office eva.luation and management of the a.dult patient. Lippincott Williarns and Wilkins. 2009. [5] Hato et al. Valacyclovir ard prednisolone treatment for Bell's palsy: a multicenter, raidomized, placebo-corrtrolled study. Otol Neurol 2007; vol 28: pgs 408-413. [6] Jscobson DM. Relative pupil-sparing third nerve palsy: etiolo8y and clirF ical r,ariables predictive of a mass. Neurology 2001;56:797. [7] Johnson 2nd ed. Appteton and Lange, 1997 L, Stetson S, Xrohel G, et al. Aspirin use and the prevention of acute ischemic cranial neNe palsy. Arn J Ophthalmol. 2000 Mar;129(3):367-71. [8] Johnson R, Griffin J, McArthur J. Current therapy in neurologic disease, Volume 1, Mosby. 2006. [9] Jung J, Kim D. Risk factom and prognosis of isolated ischemic third, fourth, or sixth qanial nerve palsies in the korean population. J Neuroophthalmol. 2015 Mar;35(l):37-40. [10] Miller N, Newman N, Biousse V, Kerrison J. Clinical Neuro. Ophthalmologr: The Essentials. 2nd Fdition. Philadelphia: Lippincott Williams and Wilkins, 2008. [11] May M, Schaitkin B. The focial nerve, 2nd ed. Thieme,2000. [12] Rrmington L. Clinical Anatomy Butterworth-Heinemann, 1988. of the Visual System. Boston: [13] Roob et al. Peripheral facial palsy: etiology, diagnosis and treatment. Eur Neurol 1999; vol 41 (1); pes 3-9. [14] Sullivan et al. Early treatment with prednisolone or acyclovir palsy. N Eng J Med 2007; vol 357: pgs 1598-1607. in Bell's 188 CHAP'I'ER 13, CKANIAL NERYI' PALSY LIPDATE [15] Tamharkar M, Biousse V, Ying G, et al Isolabed thir(1, lourth, and sixth cranial nerve palsies from presumed rnicrovascular versus other causes: a prospective study. Oplrthalmology. 2013 N-ov; 1 20( 1 1 ) :2264-9 [16] Trar$actrons of the Anrerican Ophthalrnologic Socrety. Vol. XLIV. 199ti [17] Wolfie E. Eugerre WolE's Analorny of tLe Eye .urd OrLrt. W.Lruick, R (ed) Philadelphia: Saunders, 1976; 160.