neurology lecture on cranial nerve

8/7/2019 neurology lecture on cranial nerve

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NEUROLOGY LECTURE ON NEUROLOGY LECTURE ON

CRANIAL NERVESCRANIAL NERVES ALFREDO R. GUZMAN MD,FPCP ALFREDO R. GUZMAN MD,FPCP

ASSISTANT PROFESSOR ASSISTANT PROFESSORPLM CMPLM CM


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First cranial nerve

Disturbances of olfaction are uncommon inneurological practice. Alteration of taste and smell is a recognized

complication of head injury and can follow anapparently trivial upper respiratory tract infection.

Rarely, in a patient with a subfrontalmeningioma unilateral anosmia is the presentingcomplaint.

Dulling of olfaction occurs in the elderly,accompanies Parkinsons disease and is a relativelyearly feature of Alzheimers disease.


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22 ndnd cranial nervecranial nerve


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PROPTOSIS ASSOCIATED WITH RIGHT ORBITAL MENINGIOMAPROPTOSIS ASSOCIATED WITH RIGHT ORBITAL MENINGIOMA ..Meningiomas of th e op t ic nerve s h ea th lead t o gradual visual failure associa t ed w ithMeningiomas of th e op t ic nerve s h ea th lead t o gradual visual failure associa t ed w ith

mild prop t osismild prop t osis


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HO RNER S SYNDROM E before and after instilation of of 4%HO RNER S SYNDROM E before and after instilation of of 4%

cocaine of unaffected left pupilcocaine of unaffected left pupil


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HORNER S SYNDROME. A ffec t ed rig ht pupil af t er ins t ila t ion of HORNER S SYNDROME. A ffec t ed rig ht pupil af t er ins t ila t ion of 4% cocaine4% cocaine


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TONIC PUPIL SYNDROME. Th e lef t pupil is dila t edTONIC PUPIL SYNDROME. Th e lef t pupil is dila t ed


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TONIC PUPILS. A ft er 1 min . near effor t, th e affec t ed lef t pupil TONIC PUPILS. A ft er 1 min . near effor t, th e affec t ed lef t pupil is no w smaller th an th e rig ht.is no w smaller th an th e rig ht.


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TONIC PUPILTONIC PUPIL .. Gradual dila t a t ion af t er release of Gradual dila t a t ion af t er release of near s t imulus af t er a . 15 sec near s t imulus af t er a . 15 sec

and b . s t ill incomple t e af t er 60 minand b . s t ill incomple t e af t er 60 min


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IRIDOPLEGIA. D ila t ed lef t pupil w ith no response t o lig htIRIDOPLEGIA. D ila t ed lef t pupil w ith no response t o lig htor accommoda t ion .or accommoda t ion .

An isola t ed iridoplegia , w ith a fixed dila t ed pupil unresponsive t o lig ht An isola t ed iridoplegia , w ith a fixed dila t ed pupil unresponsive t o lig htor a near effor t, can resul t from an organic insul t t o th e ciliary or a near effor t, can resul t from an organic insul t t o th e ciliary ganglion , bu t is usually th e consequence of th e acciden t al or ganglion , bu t is usually th e consequence of th e acciden t al or

delibera t e ins t illa t ion of mydria t ic eyedelibera t e ins t illa t ion of mydria t ic eye--drops .drops .


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ARGYLL ROB ERTSO N PUPILS. The right pupil is small, slightly irregular, ARGYLL ROB ERTSO N PUPILS. The right pupil is small, slightly irregular,and fixed to light although reacts to near stimulus. The left eye isand fixed to light although reacts to near stimulus. The left eye is

artificial.artificial.


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BENEDICT S SYNDROME. Th ird lef t nerve palsy w ith pupil BENEDICT S SYNDROME. Th ird lef t nerve palsy w ith pupil sparingsparing


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Compression of the nerve in its distal course is most often the result of aCompression of the nerve in its distal course is most often the result of aposterior communicating aneurysm. H ere the pupil is inevitably affected if theposterior communicating aneurysm. H ere the pupil is inevitably affected if the

paresis is complete. In incomplete lesions, however, there may be partialparesis is complete. In incomplete lesions, however, there may be partialpupillary sparing.pupillary sparing.

33 RDRD NRVENRVEPALSY DUEPALSY DUETO POSTETO POSTE --

RIORRIORCOMMUNICOMMUNI

CATINGCATING ANEURYSM ANEURYSM


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PO STERIPO STERIO RO R

COMM .COMM . ARTERY ARTERY

ANEURYS ANEURYSMM


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Diabe t es is an Diabe t es is an impor t an timpor t an t

cause of an cause of an isola t ed th ird isola t ed th ird nerve palsy nerve palsy

and it may be and it may be th e firs tth e firs t

manifes t a t ion manifes t a t ion of th e of th e

condi t ion .condi t ion .Typically , th e Typically , th e

paresis (R ) is paresis (R ) is painful and painful and t ends t o spare t ends t o spare

th e pupil .th e pupil .


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Various ocular mo t or Various ocular mo t or palsies h ave been palsies h ave been

described in described in associa t ion w ithassocia t ion w ith

Herpes op hth almicus .Herpes op hth almicus .Mos t common is a Mos t common is a

par t ial par t ial or comple t e or comple t e oculomo t or palsy .oculomo t or palsy .


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erran regenera on o erran regenera on o th e th ird nerve is th e th ird nerve is

encoun t ered follo w ing encoun t ered follo w ing t rauma or compression of t rauma or compression of

th e nerve by aneurysm .th e nerve by aneurysm . Various anomalous Various anomalous

movemen t s can resul t,movemen t s can resul t,wh ich include adduc t ion wh ich include adduc t ion

on a tt emp t ed do w n or up on a tt emp t ed do w n or up gaze , lid re t rac t ion on gaze , lid re t rac t ion on a tt emp t ed medial or do w n a tt emp t ed medial or do w n

gaze , and cons t ric t ion of gaze , and cons t ric t ion of th e pupil during th e pupil during

a tt emp t ed adduc t ion . Th e a tt emp t ed adduc t ion . Th e mos t common of th ese is mos t common of th ese is

lid eleva t ion on a tt emp t ed lid eleva t ion on a tt emp t ed do w n gaze .( N o t e do w n gaze .( N o t e

re t rac t ed lid on medial re t rac t ed lid on medial gaze of lef t eyegaze of lef t eye


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Four th nerve palsies are uncommon . T rauma is th e usual Four th nerve palsies are uncommon . T rauma is th e usual t rigger . I n addi t ion t o th e defec t of eye movemen t, th ere t rigger . I n addi t ion t o th e defec t of eye movemen t, th ere

t ends t o be a ch arac t eris t ic h ead t ilt a w ay from th e t ends t o be a ch arac t eris t ic h ead t ilt a w ay from th e

affec t ed eye .affec t ed eye .


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Bila

teral

6Bila

teral

6 ththnerve palsy nerve palsy in pa t ien tin pa t ien t

w ith pon t ine w ith pon t ine lesion . Th ere lesion . Th ere

is a is a

t endency t o t endency t o A. A.

convergence convergence w ithw ith

incomple t e incomple t e abduc t ion of abduc t ion of th e B. rig htth e B. rig htand C. lef tand C. lef t

eyeeye


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Rig ht 6Rig ht 6thth

nerve palsy . A.nerve palsy . A.rig ht la t eral gaze B. for w ard rig ht la t eral gaze B. for w ard gaze C. Lef t la t eral gazegaze C. Lef t la t eral gaze


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Bila t eral six th nerve Bila t eral six th nerve palsies are encoun t ered palsies are encoun t ered

in some pa t ien t s w ithin some pa t ien t s w ithraised in t racranial raised in t racranial

pressurepressure .. ATTEMPTED ATTEMPTEDGAZE TO THEGAZE TO THE

a . RIGHTa . RIGHTb . LEFTb . LEFT


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OPTIC NERVE SHEATH MENINGIOMA.MILD LEFTOPTIC NERVE SHEATH MENINGIOMA.MILD LEFTPROPTOSISPROPTOSIS


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ORBITALORBITAL

CAVERNOUSCAVERNOUSHEMANGIOMA.HEMANGIOMA.MRIMRI

APPEARANCE APPEARANCE


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SPHENOIDAL WING MENINGIOMA SHOWING RT PROPTOSISSPHENOIDAL WING MENINGIOMA SHOWING RT PROPTOSIS


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CAVERNOUS ANEURYSM. CT APPEARANCE a . BEFORE ANDCAVERNOUS ANEURYSM. CT APPEARANCE a . BEFORE ANDb . AFTER IV CONTRASTb . AFTER IV CONTRAST

CALCIFICATION (CONTRAST ) ENHANCEMENT INT THE ANEURYSMCALCIFICATION (CONTRAST ) ENHANCEMENT INT THE ANEURYSM


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CAROTICO CAVERNOUS FISTULA. R ig ht prop t osis and gross edema of CAROTICO CAVERNOUS FISTULA. R ig ht prop t osis and gross edema of th e eyelids and periorbi t al t issuesth e eyelids and periorbi t al t issues


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Caro t icocavernous fis t ulae are usually t rauma t ic or consequen t t o rup t ure of a cavernous aneurysm .

Gross conges t ion of th e veins draining t o th e cavernous sinus follo w s , including th e

superior op hth almic and conjunc t ival veins .Typically , th ere is pulsa t ing exop hth almos associa t ed w ith an orbi t al brui t, op hth almoplegia , orbi t al pain and gross prop t osis , t oge th er w ith oedema of th e lids and conjunc t ivae


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VERICAL SKEW DEVIATION IN PATIENT WITH PONTINE VERICAL SKEW DEVIATION IN PATIENT WITH PONTINELESION.LESION.

Ske w devia t ion is associa t ed w ith a ver t ical imbalance of Ske w devia t ion is associa t ed w ith a ver t ical imbalance of

th e visual axes and can occur w ith lesions a t vir t ually any th e visual axes and can occur w ith lesions a t vir t ually any level of th e brain s t em .level of th e brain s t em .


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BILATERALBILATERAL

INTERINTER --NUCLEARNUCLEAROPHTHALOPHTHAL --MOPLEGIAMOPLEGIA


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INO OFINO OF ABDUCTION. ABDUCTION.Th ere is impairmen tTh ere is impairmen t

of abduc t ion of abduc t ion bila t erally in th is bila t erally in th is pa t ien t w ith h erpes pa t ien t w ith h erpes simplex simplex

encep h ali t is .encep h ali t is .


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RIGHT GAZE PALSY +RIGHT INORIGHT GAZE PALSY +RIGHT INOTh e ` oneTh e ` one- -andand- -aa--h alf syndromeh alf syndrome

I f a vascular or demyelina t ing lesion involving th e I f a vascular or demyelina t ing lesion involving th e mlf ex t ends t o th e paramedian pon t ine re t icular mlf ex t ends t o th e paramedian pon t ine re t icular forma t ion (PPRF ) or th e adjacen t abducens nucleus ,forma t ion (PPRF ) or th e adjacen t abducens nucleus ,

a combina t ion of a la t eral gaze paresis w ith an a combina t ion of a la t eral gaze paresis w ith an ipsila t eral I n t ernuclear op hth almoplegia resul t s .ipsila t eral I n t ernuclear op hth almoplegia resul t s .Th e only remaining h orizon t al eye movemen t is Th e only remaining h orizon t al eye movemen t is

abduc t ion of th e con t rala t eral eye wh ich may t end abduc t ion of th e con t rala t eral eye wh ich may t end t o lie in an abduc t ed posi t ion .t o lie in an abduc t ed posi t ion .


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a&ba&b--Bila t eral h orizon t al gaze paresisBila t eral h orizon t al gaze paresisc&dc&d-- Ver t ical gaze is largely preserved th oug h th ere is ver t ical a slig ht Ver t ical gaze is largely preserved th oug h th ere is ver t ical a slig htver t ical ske w devia t ionver t ical ske w devia t ion ..


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Lesions of th e abducens nucleus or th e paramedian pon t ine re t icular forma t ion produce a h orizon t al gaze paresis .

I f th e ros t ral PPRF is affec t ed , ves t ibular evoked movemen t s (e .g . w ith th e dolls h ead maneuver) can overcome th e paresis .

I f all h orizon t al eye movemen t s are affec t ed , a more caudal lesion ex t ending in t o th e six th nerve and ves t ibular nuclei is likely .

I f th e lesion is bila t eral , th en a comple t e h orizon t al gaze paresis follo w s .


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TRIGEMINAL LESION.TRIGEMINAL LESION.Devia t ion of th e ja w t o Devia t ion of th e ja w t o

th e lef t due t o th e th e lef t due t o th e unopposed ac t ion of th e unopposed ac t ion of th e

rig ht p t erygoids .rig ht p t erygoids .


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TRIGEMINAL LESIONTRIGEMINAL LESION ..a . W as t ing of th e lef t t emporalis w ith b . normal rig ht t emporalisa . W as t ing of th e lef t t emporalis w ith b . normal rig ht t emporalis


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I n t rigeminal neuropa th y ,

progressive loss

of

facial

sensa

tion

occurs w ith ou t involvemen t of mo t or fibers .

Th e disorder is of unkno w n e t iology .

Even t ually , th e loss of facial sensa t ion may resul t in neuropa th ic ulcera t ion or t issue loss .

SEE BELOW!


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Th e seven th nerve , accompanied by th e eig hth nerve , passes across th e

cerebellopon t ine angle before en t ering th e in t ernal audi t ory mea t us .La t er , th e seven th nerve w ith th e

nervus in t ermedius , en t ers th e facial canal . Mos t of th e seven th nerve fibres are mo t or and supply th e muscles of facial expression , t oge th er w ith

buccina t or , s t ylo h yoid , th e pos t erior belly of digas t ric and s t apedius .


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Th e ch orda t ympani branc h con t ains t as t e fibres from th e an t erior tw o- th irds of th e t ongue along w ith secre t omo t or fibres t o th e submaxillary and submandibular glands .

Secre t omo t or fibres t o th e lacrimal gland pass via th e grea t er superficial pe t rosal nerve and th e sp h enopala t ine ganglion .

Th e facial nerve con t ains a small number of soma t ic sensory fibres conveying impulses from an area be h ind

th e ear .


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UPPER MOTORNEURON LESION FACIAL WEAKNESS ON THE RIGHTUPPER MOTORNEURON LESION FACIAL WEAKNESS ON THE RIGHT


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PERIPHERAL FACIAL NERVE PARALYSIS (BELL S PALSY )PERIPHERAL FACIAL NERVE PARALYSIS (BELL S PALSY )


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RAMSAY HUNT SYNDROME. A, H erpe t ic disrup t ion over th e h ard RAMSAY HUNT SYNDROME. A, H erpe t ic disrup t ion over th e h ard pala t e and b . over th e pinnapala t e and b . over th e pinna

I n th e Ramsay Hun t syndrome (genicula t e zos t er) , a h erpe t ic I n th e Ramsay Hun t syndrome (genicula t e zos t er) , a h erpe t ic

infec t ion affec t s th e genicula t e ganglion . I n addi t ion t o th e facial infec t ion affec t s th e genicula t e ganglion . I n addi t ion t o th e facial paresis , a h erpe t ic erup t ion may be found ei th er in th e ex t ernal paresis , a h erpe t ic erup t ion may be found ei th er in th e ex t ernal

audi t ory canal , th e pinna or th e pala t eaudi t ory canal , th e pinna or th e pala t e


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Bilateral lower motor Bilateral lower motor neurone facialneurone facialparesisparesis can becan be

particularly difficult toparticularly difficult torecognize.recognize.

There is a loss of facialThere is a loss of facialexpressivity. Causesexpressivity. Causes

include the Guillaininclude the Guillain- -BarrBarrsyndrome and leprosy.syndrome and leprosy.Causes of a unilateralCauses of a unilaterallower motor neuronelower motor neuronefacial paresis includefacial paresis include

trauma, compression of trauma, compression of the nerve in thethe nerve in the

cerebellopontine anglecerebellopontine angleand involvement of theand involvement of the

nerve, or its parentnerve, or its parentnucleus, within the brainnucleus, within the brainstem. A sixth nerve palsystem. A sixth nerve palsy

is likely with nuclear is likely with nuclear seventh nerve lesions.seventh nerve lesions.


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HEMIFACIALHEMIFACIALSPASM ON THESPASM ON THE

LEFTLEFT


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Hemifacial spasm consis t s of con t rac t ion of muscles supplied by th e

facial nerve .Th e condi t ion usually begins around th e

eye bu t can la t er affec t th e wh ole of one side of th e face . I n es t ablis h ed cases , a lo w er mo t or neurone paresis appears .

Th e condi t ion is considered t o be th e resul t of cross-compression of th e seven th nerve by small t umours or more commonly by an aberran t ar t ery .


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Facial and pala t al myoclonus occur w ith a varie t y of brain s t em pa th ological

disorders,

particularly

trauma

or

cerebrovascular disease .

Th e myoclonus usually appears several mon th s af t er th e ini t ia t ing even t and th en t ends t o persis t. A myoclonic con t rac t ion of muscle occurs ,

generally a t 80 -1 2 0H z.

Th e pa t ien t some t imes complains of a persis t en t clicking noise and th e rh y th mical na t ure of th e pala t al movemen t can be apprecia t ed by asking th e pa t ien t t o sing a no t e .


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THE EIGHTH CRANIAL NERVE Th e eig hth nerve con t ains a ves t ibular

componen t wh ic h provides informa t ion on h ead posi t ion and movemen t, t oge th er w ithan acous t ic componen t responsible for th e sense of h earing .

Of relevance t o th e neurologis t are th ose cases of unila t eral deafness due t o a compressive lesion w ith in th e

cerebellopontine

angle

.It h as been es t ima t ed th a t 10 per cen t of

cases of unila t eral h earing loss are due t o an acous t ic neuroma , wh ic h accoun t s for 8

per cen t of all in t racranial t umours .


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Th e t umours arise w ith in th e in t ernal audi t ory mea t us , t ypically from th e superior ves t ibular componen t of th e nerve . As th e t umour expands , it ex t ends

in t o th e cerebellopon t ine angle , la t er causing compression of th e brain s t em and cerebellum (F ig 14.59 ) .


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ACOUS ACOUS --TICTIC

NEURONEUROMAMA

TUMO RTUMO RWITH WITH

C YSTIC C YSTIC COM POCOM PO--

NENTNENT


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ACOUSTIC NEUROMA ACOUSTIC NEUROMAa . AUDIOMETRY SHOWING LEFT SIDED DEAFNESS MAXIMAL FOR HIGHa . AUDIOMETRY SHOWING LEFT SIDED DEAFNESS MAXIMAL FOR HIGH

TONES b . CALORIC RESPONSE SHOWING INCOMPLETE LEFT CANALTONES b . CALORIC RESPONSE SHOWING INCOMPLETE LEFT CANALPARESISPARESIS


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Removal of an

acous t ic neuroma may lead t o facial w eakness , th e effec t s of wh ic hcan be par t ly offse tby facio h ypoglossal

anas t omosis .


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ATROPHY OFATROPHY OF

THE LEFT SIDETHE LEFT SIDEOF THEOF THE

TONGUETONGUE

FOLLOWING AFOLLOWING AFASCIOHY-

POGLOSSAL

ANASTO-MOSIS.


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THE NINTH CRANIAL NERVE

Th e glossop h aryngeal nerve is predominan t ly sensory .

It s func t ion is bes t t es t ed by applying

a painful s t imulus t o th e t onsillar fossa .I sola t ed lesions of th e nerve are rare .I n glossop h aryngeal neuralgia ,

paroxysms of pain in th e t ongue or th roa t occur , analogous t o th e facial paroxysms of t rigeminal neuralgia .


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Th e tent h cranial nerve

Th e t en th nerve is more readily assessed . Itis responsible for th e efferen t componen t of th e gag reflex .

I n a unila t eral t en th nerve palsy , th e sof tpala t e lies lo w er on th e affec t ed side and along w ith th e pos t erior p h aryngeal w all devia t es t o th e in t ac t side during p h ona t ion (F ig 14.6 3 ) (Video) .

Th e vocal cord on th e affec t ed side lies fixed in a posi t ion mid w ay be tw een abduc t ion and adduc t ion resul t ing in a slig ht ly h oarse voice .


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1010 TH TH NN PALSY LEFT NN PALSY LEFT

a . THE LEFT SIDEa . THE LEFT SIDEOF THE SOFTOF THE SOFTPALATE ISPALATE ISSLIGHTLYSLIGHTLY

DEPRESSED ANDDEPRESSED ANDb . THE PALATEb . THE PALATE

SLIGHTLYSLIGHTLY

DEVIATES TO THEDEVIATES TO THERIGHT ONRIGHT ONPHONATIONPHONATION


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THE ELEVENTH CRANIAL NERVE The eleventh cranial nerve, or at least

its spinal component, arises from thesegments C l to C4 and supplies thesternomastoid and trapezius muscles.

Lesions of the nerve outside the jugularforamen cause paralysis of sternomastoid and the upper fibres of trapezius, the lower half being spared onaccount of its innervation by spinalsegments C3 and C4.


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1111 TH TH CN PALSY CN PALSY a . WAISTINGa . WAISTING

OF THEOF THE

STERNOMASTSTERNOMASTOID AT RESTOID AT REST AND b . & c . AND b . & c .

DURINGDURING

HEADHEADROTATIONROTATION


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THE TWELFTH CRANIAL NERVE A lesion of th e h ypoglossal nerve

produces ipsila t eral w as t ing and fascicula t ion of th e t ongue

Th ere is litt le effec t on p h ona t ion or

s w allo w ing . B ila t eral involvemen t of th e t ongue a t th e lo w er mo t or neurone level produces severe immobili t y .

Th e problem is usually par t of a bulbar

palsy w ith a tt endan t deficiencies of movemen t in th e pala t e , p h arynx and larynx , th e consequence mos t commonly of mo t or neurone disease .


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ipsila t eral w as t ing and fascicula-t ion of

th e t ongue


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neurology lecture on cranial nerve

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