SARAF OKULOMOTORIUS

) SARAF OKULOMOTORIUS (N. III)Nukleus saraf okulomotorius terletak sebagian di depan substansia grisea periakuaduktal (Nukleus motorik) dan sebagian lagi di dalam substansia grisea (Nukleus otonom).Nukleus motorik bertanggung jawab untuk persarafan otot-otot rektus medialis, superior, dan inferior, otot oblikus inferior dan otot levator palpebra superior. Nukleus otonom atau nukleus Edinger-westhpal yang bermielin sangat sedikit mempersarafi otot-otot mata inferior yaitu spingter pupil dan otot siliaris.

4) SARAF TROKLEARIS (N. IV)Nukleus saraf troklearis terletak setinggi kolikuli inferior di depan substansia grisea periakuaduktal dan berada di bawah Nukleus okulomotorius. Saraf ini merupakan satu-satunya saraf kranialis yang keluar dari sisi dorsal batang otak. Saraf troklearis mempersarafi otot oblikus superior untuk menggerakkan mata bawah, kedalam dan abduksi dalam derajat kecil.5) SARAF TRIGEMINUS (N. V)Saraf trigeminus bersifat campuran terdiri dari serabut-serabut motorik dan serabut-serabut sensorik. Serabut motorik mempersarafi otot masseter dan otot temporalis. Serabut-serabut sensorik saraf trigeminus dibagi menjadi tiga cabang utama yatu saraf oftalmikus, maksilaris, dan mandibularis. Daerah sensoriknya mencakup daerah kulit, dahi, wajah, mukosa mulut, hidung, sinus. Gigi maksilar dan mandibula, dura dalam fosa kranii anterior dan tengah bagian anterior telinga luar dan kanalis auditorius serta bagian membran timpani.

6) SARAF ABDUSENS (N. VI)Nukleus saraf abdusens terletak pada masing-masing sisi pons bagian bawah dekat medula oblongata dan terletak dibawah ventrikel ke empat saraf abdusens mempersarafi otot rektus lateralis.

Third Nerve Palsy

What is a third nerve palsy?

The third cranial nerve controls movement of four eye muscles that move the eye in, up, down and torsion. The third cranial nerve also controls constriction of the pupil, the eyelid and the ability of the eye to “focus” or accommodate and upper eyelid position. A complete third nerve palsy  causes a totally closed eyelid and a down and out deviation of the eye. The eye cannot

move in or up and the pupil is typically enlarged and does not react normally to light. A partial third nerve palsy affects to varying degrees any of the functions controlled by the third cranial nerve.

What are the symptoms of third nerve palsy?

People over 10 years of age with third nerve palsy.usually have double vision due to misalignment of the eyes. If a droopy eyelid (ptosis) covers the pupil, diplopia may not be noticeable.   Ptosis of the eyelid or an enlarged pupil may be the first  sign of a third nerve palsy Young children usually do not complain of double vision. Figure 1 demonstrates the droopy eyelid. Figure 2 demonstrates outward position of the eye underneath the droopy eyelid signifying the palsy.

What causes third nerve palsy?

A third nerve palsy may be present at birth, and the exact cause may not be clear.  Acquired third nerve palsy can be associated with head injury, infection, migraine, brain tumor, aneurysm, diabetes and high blood pressure.

 What problems develop in children with third nerve palsy?

 Children may develop amblyopia in the involved eye. Amblyopia can often be treated  by patching the unaffected eye. Patching may be necessary for several years, sometimes until age 9 years. Children with severe third nerve palsy often do not have binocular vision (simultaneous perception with both eyes), and stereopsis (three dimensional vision) is often absent. An abnormal head posture may allow binoculoar vision. Partial palsy is often associated with the development of binocular vision.

What can be done to correct third nerve palsy?

Unfortunately, there is no treatment to re-establish function of the weak nerve other than the body’s own healing. Relief of pressure on the third nerve from a tumor or blood vessel (aneurysm) with surgery may improve third nerve palsy.

The ophthalmologist will usually wait at least 6 months after onset for possible spontaneous improvement. During this observation period,  patching one eye can alleviate double vision. Prism spectacles may relieve diplopia for some. If the palsy is present after 6 months, eye muscle

surgery can be performed to  realign the eyesin straight ahead gaze. The more severe the third nerve palsy, the more difficult it is to re-establish eye movements and an area of single binocular vision, The remaining diplopia can be quite bothersome. Surgery can be performed to raise the eyelid in selected cases.

PENDAHULUANSaraf otak (nervus cranialis) adalah saraf perifer yang berpangkal pada batang otak dan otak. Fungsinya sebagai sensorik, motorik dan khusus. Fungsi khusus adalah fungsi yang bersifat panca indera, seperti penghidu, penglihatan, pengecapan, pendengaran dan keseimbangan.

Saraf otak terdiri atas 12 pasang, saraf otak pertama langsung berhubungan dengan otak tanpa melalui batang otak, saraf otak kedua sampai keduabelas semuanya berasal dari batang otak. Saraf otak kedua dan ketiga berpangkal di mesensefalon, saraf otak keempat, lima, enam dan tujuh berinduk di pons, dan saraf otak kedelapan sampai keduabelas berasal dari medulla oblongata. (1)

ANATOMINervus okulomotorius berasal dan inti yang terletak di sisi ventrolateral substansia grisea sentralis mesensefalon sekitar akwaduktus. Penataan inti tersebut masih belum  diketahui   secara pasti.  Tetapi  mungkin sekali sebagai berikut.

Inti median ialah tunggal dan dinamakan inti dari Perlia. Inti ini mengurus konvergensi dan akomodasi. Inti yang lateral ialah sepasang. Salah satu dari kelompok lateral itu tersusun oleh sel-sel yang berukuran kecil.  Inilah inti dari Edinger Westphal yang mengurus konstnksi pupil. Inti lateral lainnya terdiri dari motoneuron yang berukuran besar. Serabut-serabutnya menyarafi muskulus levator palpebrale, rektus superior, oblikus inferior, rektus medialis dan rektus inforior. Baik serabut-serabut visero motorik {dari inti dari EdingerWestphal), maupun serabut-serabut somatomotorik dari inti lateral lainnya menyusun nervus okulomotorius ipsilateral. Lain halnya dengan serabut-serabut yang berasal dari inti median yang tunggal. Mereka ikut menyusun nervus okulomotorius kedua sisi.

Setelah mereka meninggalkan intinya nervus okulomotorius menuju ke ventral dan melintasi fasikulus longitudinalis medialis, nukleus ruber dan tepi medial substansia nigra untuk muncul pada permukaan ventral di tepi medial krus serebri (pedunkulus serebri). Kemudian ia menjulur ke depan, di antara arteria serebeli superior dan arteria serebri posterior dekat arteria komunikans posterior. Di tingkat prosesus klinoideus posterior ia menembus dura mater pada suatu tempat di antara daun tentorium serebeli yang bebas dan yang lidak bebas. Kemudian ia melanjutkan perjalanannya ke depan melalui dinding lateral sinus kavernosus. Di situ ia berdekatan dengan saraf otak keempat, keenam dan cabang pertama saraf otak kelima. Ia meninggalkan dinding lateral sinus tersebut untuk tiba di fisura orbitalis superior, di antara kedua bagian dari muskulus rektus lateralis. Di sini ia bercabang dua. Yang atas menyarafi muskulus levator palpebrale dan muskulus oblikus inferior. Dan cabang bawahnya menyarafi muskulus rektus medialis, rektus inferior dan oblikus inferior.

Nervus okulomotorius mengurus gerakan bola mata secara konjugat dan diskonjugatif. Gerakan bola mata konjugat berarti kedua bola mata bergerak ke suatu jurusan sedangkan pada gerakan diskonjugatif kedua bola mata bergerak ke arah yang saling berlawanan, seperti pada waktu konvergensi dan divergensi. Pada gerakan konjugat dan diskonjugatif, kedua nervus okulomotorius bekerja sama dengan sarafotak -sarafotak okuler lainnya, yaitu nervus trokhlearis dan nervus abdusens. (1)

Secara ringkas, fungsi nervus okulomotorius, mempersarafi otot-otot bola mata antara lain:

r  Muskulus recti superior, inferior dan medial yang fungsinya menarik bola mata ke arah superior, inferior dan medial.

r  Muskulus obligus inferior, fungsinya memutar bola mata menghadap atas-lateral.

r  Muskulus levator palpebra superior, fungsi mengangkat palpebra superior.

r  Muskulus ciliaris, fungsi dipengaruhi oleh saraf simpatis dan parasimpatis.

r  Muskulus sphingter pupil, fungsi dipengaruhi oleh saraf parasimpatis ® jika dirangsang pupil mengecil.

r  Muskulus dilatator pupil, fungsi dipengaruhi oleh saraf parasimpatis ® jika dirangsang pupil membesar.

Fungsi N. Trochlearis, mempersarafi muskulus obligus superior ® fungsi memutar bola mata menghadap bawah-lateral.

Fungsi N. Abdusen, mempersarafi muskulus rectus lateral ® fungsi menarik bola mata kearah lateral. (2)

DEFINISIParesis nervus okulomotorius atau paralisis parsial nervus okulomotorius adalah gangguan fungsi motorik akibat adanya lesi jaringan saraf pada nervus okulomotorius. (3)

ETIOLOGIParesis nervus okulomotorius dapat disebabkan oleh hal-hal sebagai berikut:

1. Meningitis (meningitis tuberkulosa, luetika, dan purulenta).2. Lues serebrospinal.3. Infiltrasi karsinoma anaplstik dari nasofaring.4. Stroke (infark atau perdarahan di mesensefalon, yang menimbulkan sindroma dari

weber).5. Trauma kapitis (fraktur basis kranii, traksi pada nervus okulomotorius).6. Aneurisma pada sirkulasi arteriosus Willisii.7. Migren.8. Neuritis reumatika.

9. Neuropatia pasca-difteri.

10.  Herpes zoster oftalmikus.  (1,4)

MANIFESTASI KLINISManifestasi klinis yang ditimbulkan oleh paresis nervus okulomotorius dapat berupa hal dibawah ini:

1. Ptosis, hal ini disebabkan oleh karena kelupuhan musculus levator palpebra (sinistra atau dekstra) sesuai dengan letak lesi.

2. Jika lesi pada sinistra, maka bola mata kiri hanya dapat bergerak ke samping kiri. Bila melihat ke bawah, bola mata itu akan agak memutar, karena adanya kontraksi dari musculus obligus superior.

3. Pupil midriasis dengan refleks cahaya dan konvergensi yang negatif.4. Tidak dapat melakukan akomodasi.5. Strabismus divergens.6. Diplopia dengan gambar kembar heteronim. (1,4,5)

Suatu paralisis totalis dari nervus okulomotorius hanyalah dapat timbul bila nervus okulomotorius itu oleh karena suatu sebab misalnya trauma sehingga menjadi terputus. Bila lesi itu terletak pada nucleus okulomotorius (yang mengambil tempat yang cukup luas), maka oleh karena selalu masih akan terdapat nuclei yang bebas lesi, akan timbul suatu paralisis yang parsial.

Suatu paralisis nervus okulomotorius yang parsial dapat pula kita jumpai pada lesi di perifer, yaitu bila paralisis nervus okulomotorius itu ditimbulkan oleh suatu meningitis. Suatu meningitis akan menghinggapi hanya bagian marginal dari nervus okulomotorius tersebut. Bagian sentral dari saraf itu akan terhindar.

Dengan demikian, maka fungsi nervus okulomotorius itu hanyalah akan terganggu secara parsial. Bila pada mata itu hanya tampak ptosis saja, maka kita harus pertimbangkan kemungkinan-kemungkinan akan adanya:

1. Lesi parsial nervus okulomotorius.2. Sindrom Horner’s.3. Miastenia gravis4. Pseudoptosis karena trakoma. (1,4,5,6,7,8)

DIAGNOSISDiagnosis Paresis nervus okulomotorius dapat ditegakkan dengan melakukan anamnesis tentang riwayat penyakit, termasuk juga riwayat keluhan, berapa lama keluhan sudah timbul dan apakah unilateral ataukah bilateral.

Pemeriksaan nervus okulomotorius biasanya dilakukan bersama-sama dengan pemeriksaan nervus troklearis dan nervus abdusen, pemeriksaan tersebut terdiri atas:

1. Celah kelopak mata

Pasien disuruh memandang lurus ke depan ® kemudian dinilai kedudukan kelopak mata terhadap pupil dan iris

1. Pupil

Yang perlu diperiksa adalah (1) ukuran: apakah normal (diameter 4-5 mm), miosis, midriasis atau pin pont pupil, (2) bentuk: apakah normal, isokor atau anisokor, (3) posisi: apakah central atau eksentrik, (4) refleks pupil: refleks cahaya langsung ® cahaya diarahkan pada satu pupil ® reaksi yang tampak untuk kontraksi pupil homolateral, refleks cahaya tidak langsung (konsensual /crossed light refleks) ® selain kontraksi homolateral juga akan tampak kontraksi kontralateral, refleks akomodasi-konvergensi ® pasien diminta melihat jauh kemudian melihat ketangan pemeriksa yang diletakkan 30 cm di depan hidung pasien. Pada saat melihat tangan pemeriksa, kedua bola mata pasien bergerak secara konvergensi (kearah nasal) dan tampak pupil mengecil. Refleks ini negatif pada kerusakan saraf simpatikus leher, refleks siliospinal ® refleks nyeri ini dilakukan dalam ruangan dengan penerangan samar-samar. Caranya ialah merangsang nyeri pada daerah leher dan sebagai reaksi pupil akan melebar pada sisi ipsilateral. Refleks ini terjadi bila ada benda asing pada kornea atau intraokuler, atau pada cedera mata atau pelipis, refleks okulosensorik ® refleks nyeri ini adalah konstriksi atau dilatasi disusul konstriksi, sebagai respons rangsang nyeri di daerah mata atau sekitarnya.

1. Gerakan bola mata

Fungsi otot-otot ekstrinsik bola mata dinilai dengan gerakan bola mata keenam arah yaitu lateral, medial, lateral atas, medial atas, medial atas dan medial bawah, cara: pasien menghadap ke depan dan bola mata digerakkan menurut perintah atau mengikuti arah objeck.

Kelainan-kelainan yang dapat terjadi:

1. Kelemahan otot-otot bola mata (opthalmoParesis/opthalmoplegi) berupa:(1) gerakan terbatas, (2) kontraksi skunder dari anta-gonisnya, (3) strabismus, (4) diplopia

2. Nistagmus (gerakan bolak-balik bola mata yang involunter) ® dapat terlihat saat melihat ke samping, atas, bawah. (4,5,6,7,8)

DAFTAR RUJUKAN

1. Mardjono M, Sidharta P. Sarafotak dan Patologinya. Dalam: Neurologi Klinis Dasar. Penerbit PT. Dian Rakyat. Jakarta. 2000: 114 – 82.

2. Sidarta Ilyas. Anatomi dan Fisiologi Otot Pengerak Bola Mata. Dalam: Ilmu Penyakit Mata. Fakultas Kedokteran Universitas Indonesia. Jakarta. 2000: 233 – 65.

3. Dorland: Kamus Kedokteran, Penerbit Buku Kedokteran EGC, Edisi 26, cetakan II, Jakarta 1996

4. Prof. Dr. I. Gusti Ng. Gd. Ngoerah. Nervi Kranialis. Dalam: Dasar-Dasar Ilmu Penyakit Saraf. Penerbit Universitas Airlangga. Surabaya. 1990: 103 – 130.

5. Sylvia A. Price. Lorraine M. Wilson. Pemeriksaan Saraf Kranial. Dalam: Patofisiologi Konsep Klinis Proses-Proses Penyakit Edisi 4. Penerbit Buku Kedokteran EGC. Jakarta. 1995: 945 – 6.

6. Judana A, Santoso D, Kusumoputro S. Saraf – Saraf Otak. Dalam: Pedoman Praktis Pemeriksaan Neurologi. Penerbit Bagian Neurologi Fakultas Kedokteran Universitas Indonesia. Jakarta. 1978: 10 – 21.

7. Http://www.yahoo.net/seach/cache?/neuro24.de/hirnnerven_oculomotorius.htm .8. Http://www.yahoo.net/search/cache?/angelfire.com/nc/neurosurgery/Topik.html .

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Question: What does a fourth nerve palsy look like and what causes it?

Answer: The trochlear nerve (CN4) only controls the superior oblique. This muscle has a funny course, and runs through a pulley at the superior-medial wall of the eye socket. Because of this change in direction, the superior oblique muscle works mainly as an intorter, though it does perform some vertical movement, especially when the eye looks medially.

Patients will often complain of a vertical diplopia, especially when looking away from the lesion. They may develop a head-tilt away from the affected eye. On cross cover testing, you’ll find a vertical hypertropia of the affected eye that worsens when that eye is looking medially toward the nose, especially when reading.

Fourth nerve palsies can occur from DM/HTN ischemia, like all palsies. They can also be:

Trauma (that fourth nerve pops off the dorsally and has a long course to traverse) Congenital palsy that decompensates with age Tumor

Fourth Nerve (Superior Oblique) PalsyWhat is a fourth nerve palsy?

The fourth cranial nerve innervates the superior oblique muscle, so weakness of the nerve is also known as superior oblique palsy.  Weakness of the superior oblique muscle causes a combination of vertical, horizontal and torsional misalignment of the eyes.  The vertical misalignment is typically the most noticeable feature. Palsy refers to a complete weakness of a muscle while a paresis is a partial weakness. This condition is usually unilateral (one eye) but can be bilateral (both eyes).

Does superior oblique palsy cause double vision (diplopia)?

Superior oblique palsy may cause double vision because of misalignment of the eyes (the brain perceives an image from two different directions). The double vision may be vertical (one image on top of the other), diagonal (vertically and horizontally separated) and less often torsional (rotated or twisted). The torsional phenomenon occurs more frequently with acquired cases superior oblique palsy.

Why is the head tilted with superior oblique palsy?

Head tilt and/or turn is common with superior oblique palsy. The abnormal head position allows better alignment of the eyes, sometimes aiding in relief of diplopia. A child with a head tilt should be evaluated by an ophthalmologist for superior oblique palsy and other possible eye problems.

What causes superior oblique palsy?

Superior oblique palsy is most commonly congenital (present at birth). Other congenital anomalies may be associated with superior oblique palsy (e.g. a misshaped skull – craniosynostosis). A common cause of superior oblique palsy is head trauma, including relatively minor trauma. A concussion or whiplash injury from a motor vehicle accident may be sufficient to cause the problem. Rare causes of superior oblique palsy are stroke, tumor and aneurysm.

How is superior oblique palsy treated?

In cases of acquired superior oblique palsy it is important to identify and treat the underlying cause first.  Once the cause of an acquired superior oblique palsy has been treated, the ophthalmologist will usually wait 6 months for possible spontaneous resolution of the palsy. During that period, diplopia can be managed with prism glasses. Prisms merge two images into one but do not strengthen the eye muscles. If prism is not effective, patching or covering one eye can alleviate the double vision.  If the palsy does not recover over this 6 month period and if prisms are not able to adequately control the diplopia, surgery may be indicated.

The treatment of choice for congenital superior oblique palsy and for an unresolved (after 6 months) acquired palsy is typically eye muscle surgery. Surgery usually minimizes double vision, reduces the unsightly upward drift of an eye, and corrects a compensatory head tilt. Surgery is performed on one or both eyes, depending on the extent of the eye misalignment, the change of the misalignment in different directions of gaze, the amount of head tilt, and the amount of torsion.

These disorders involve paralysis of one of the cranial nerves that control eye movement (the 3rd, 4th, or 6th nerve), impairing the ability to move the eyes. How eye movement is affected depends on which nerve is affected.

The eye is moved by three pairs of muscles, controlled by the 3rd, 4th, and 6th cranial nerves. These muscles move the eye up and down, right and left, and diagonally. People with one of these palsies may have double vision when they look in certain directions.

Third Cranial Nerve (Oculomotor Nerve) Palsy

A palsy of the 3rd cranial nerve can impair eye movements, the response of pupils to light, or both. This palsy can be caused by brain disorders—such as a head injury, a bulge (aneurysm) in an artery supplying the brain, a hemorrhage, or a tumor—or by diabetes or high blood pressure.

Symptoms

The affected eye turns outward when the unaffected eye looks straight ahead, causing double vision. The affected eye can move only to the middle when looking inward and cannot move up and down. Because the 3rd cranial nerve also raises the eyelids and controls the pupils, the eyelid droops, and the pupil may be widened (dilated). It may not narrow (constrict) in response to light.

The disorder causing the palsy may worsen, resulting in a serious, life-threatening condition. For example, a severe headache may occur suddenly, or a person may become increasingly drowsy or less responsive. In such cases, the cause may be a ruptured aneurysm, which then bleeds. People may go into a coma. In such people, dilation of both pupils and lack of response to light (fixation) by both pupils indicates deep coma and possibly brain death (see Coma and Impaired Consciousness: Brain Death).

Diagnosis and Treatment

The diagnosis is based on results of a neurologic examination and computed tomography (CT) or magnetic resonance imaging (MRI). If the pupil is affected or if symptoms suggest a serious underlying disorder, CT is done immediately. If a ruptured aneurysm is suspected and CT does not detect blood, a spinal tap (lumbar puncture—see Symptoms and Diagnosis of Brain, Spinal Cord, and Nerve Disorders: How a Spinal Tap Is Done ), magnetic resonance angiography, CT angiography, or cerebral angiography is done (see Common Imaging Tests: Angiography).

Treatment depends on the cause. Emergency treatment is required if a life-threatening disorder is the cause.

Fourth Cranial Nerve (Trochlear Nerve) Palsy

A palsy of the 4th cranial nerve affects vertical eye movements. Often, the cause cannot be identified. The most common identified cause is a head injury, often due to a motorcycle accident. Occasionally, diabetes causes this palsy. Rarely, the cause is a tumor, an aneurysm, or multiple sclerosis.

One or both eyes may be affected. The affected eye cannot turn inward and down. As a result, people see double images, one above and slightly to the side of the other. Thus, going down stairs, which requires looking inward and down, is difficult. However, tilting the head to the side opposite the affected eye muscle can compensate and eliminate the double images. This position can eliminate the double images because people use eye muscles that are unaffected by the palsy to focus both eyes on an object.

Usually, the diagnosis is suspected if a person has characteristic limited eye movement. CT or MRI may be done.

The disorder causing the palsy, if identified, is treated. Eye exercises may help. Sometimes surgery is necessary to eliminate double vision.

Sixth Cranial Nerve (Abducens Nerve) Palsy

A palsy of the 6th cranial nerve affects the ability to turn the eye outward. Many disorders can cause this palsy:

Head injuries Tumors Multiple sclerosis Aneurysms Brain infections, such as meningitis, a brain abscess, or a parasitic infection Complications of an ear or eye infection Bleeding within the brain Blockage of an artery supplying the nerve, as can result from diabetes, a stroke, a

transient ischemic attack, or vasculitis (inflammation of blood vessels) Wernicke encephalopathy (commonly due to chronic alcoholism) Benign intracranial hypertension (pseudotumor cerebri—see Headaches: Idiopathic

Intracranial Hypertension) Respiratory infections (in children)

Some of these disorders put pressure on the nerve by causing nearby swelling or by increasing pressure within the skull. Others interfere with blood flow to the nerve.

If this palsy occurs alone (without other cranial nerve palsies), its cause is often never identified.

Symptoms

The affected eye cannot turn fully outward and may turn inward when people look straight ahead. Double vision occurs when people look toward the side of the affected eye. Other symptoms depend on the cause. They may include severe headache, accumulation of fluid (edema) in the conjunctiva (the membrane covering the white of the eye), numbness in the face and mouth, loss of vision, and inability to move the eye in other directions.

Diagnosis and Treatment

Usually, doctors can easily identify a 6th cranial nerve palsy, but the cause is less obvious. An ophthalmoscope is used to look into the eye and check for evidence of tumors, increased pressure, and abnormalities in blood vessels. CT or, preferably, MRI is done to exclude tumors and other abnormalities. If the results are unclear, a spinal tap (lumbar puncture) may be done to determine whether pressure within the skull is increased and whether an infection is present. If symptoms suggest vasculitis, blood is withdrawn to check for evidence of inflammation, such as certain abnormal antibodies (antinuclear antibodies and rheumatoid factor) and an abnormal erythrocyte sedimentation rate (ESR—how quickly red blood cells settle to the bottom of a test tube containing blood). After all tests are done, the cause may remain unknown.

Treatment depends on the cause. When the cause is treated, the palsy usually resolves. Palsies with no identifiable cause usually resolve without treatment within 2 months, as do those due to a blocked blood vessel.

Horner sindrome

Horner syndrome is a rare disorder that occurs when certain nerves that travel from your brain to your eyes and face are damaged.

Horner syndrome isn't a disease itself. Rather, it's a sign of another medical problem — such as a stroke, tumor or spinal cord injury. In some cases, however, no underlying cause can be found.

Horner syndrome usually affects only one side of your face. Typical symptoms of Horner syndrome include a drooping eyelid, decreased pupil size and decreased sweating on the affected side of your face.

There's no specific treatment for Horner syndrome. Instead, treatment is directed at the underlying cause, when possible.

Signs and symptoms of Horner syndrome usually occur on one side of your face and typically include:

Drooping of your upper eyelid (ptosis) and slight elevation of the lower lid Decreased pupil size in your affected eye (miosis)

Decreased or absent sweating on the affected side of your face (anhidrosis)

Rarely, a baby may be born with Horner syndrome. In these cases, the iris in the affected eye may be lighter in color than the other eye.

When to see a doctor

Horner syndrome is caused by damage to the sympathetic nerves of your face and eyes. Sympathetic nerves control your body's circulation and sweating. Depending on where the nerves are damaged, Horner syndrome is often classified in two groups.

CentralSympathetic nerves in your face start in an area of your brain known as the hypothalamus, travel through the brainstem and then down your spinal cord to enter your chest. This is the first half of their "route." Possible causes of nerve damage in this area are:

Stroke (usually a cerebral infarction or most commonly a brainstem location) Tumor Syringomyelia — a condition in which a fluid-filled cyst (syrinx) develops within your

spinal cord Cluster headaches

PeripheralFrom your chest, your sympathetic nerves go back up your neck, next to the main arteries that deliver blood to your head (carotid arteries), into your skull and then to your eyes. Nerve damage in this area may be caused by:

Spinal cord injury A tear in the inner lining of one of your carotid arteries (carotid artery dissection) An injury to a baby during birth Lung cancer in the apex of the lung

Although Horner syndrome may be a sign of one of these conditions, in some situations, a specific cause can't be found. This is known as idiopathic Horner syndrome.

An understanding of the anatomy is essential to make a logical diagnosis of the cause of acquired diplopia.[1]

Anatomy

There are 6 external ocular muscles, of which the superior oblique is supplied by the trochlear nerve (IV), the lateral rectus is supplied by the abducent nerve (VI), and all other external muscles, the internal muscles and the eyelid are supplied by the oculomotor nerve (III).

The 4 rectus muscles pull directly on the globe so that they move the eye in the direction of their name: superior, inferior, medial and lateral. The oblique muscles hook round a 'pulley' so that they move the eyes the opposite way. Hence, the superior oblique moves the eye down and out (the tramp's muscle) and the inferior oblique moves it up and out. The superior and inferior recti are not placed centrally so they have a tendency to move the eye medially but this is opposed by the obliques.

External Ocular Paralysis

Muscle Direction of pull Result of paralysis Cranial nerve

Medial rectus Medially Lateral III

Superior rectus Upwards Downwards III

Lateral rectus Laterally Medial VI

Inferior rectus Downwards Upwards III

Superior oblique Down and out Up and in IV

Inferior oblique Up and out Down and in III

Aetiology

The cause may be a space-occupying lesion in the orbit or skull, a vascular lesion, trauma or a neurological, or muscle disorder.

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Presentation

Paralysis of a muscle means that the eye will not move fully in the direction in which it pulls. At rest, when the other muscles are unopposed, the eye may deviate in the opposite direction from

the pull of that muscle.

See separate article Squints, dealing with eye movements and squint. Strabismus occurs in children when there is an imbalance between the external ocular muscles. It may be noticed on routine developmental checks or the parents may present with the complaint. Children with squints often tilt the head to one side. Strabismus will cause diplopia but the immature brain will suppress one of the images and this is why early diagnosis and treatment are important.

Symptoms

The patient will often complain of double vision. Ask when it occurs. There may be diplopia on looking to the right but not to the left. This could be due to paralysis of either the right lateral rectus or the left medial rectus. It may be intermittent and associated with tiredness. A droopy eyelid may also be noticed. Is there pain in the eye?

Signs

Look at the eyes.

Ptosis is often the first sign of weakness and it suggests the affected side. Are both pupils equal and do they react to light and accommodation? In Horner's syndrome the

pupil on the affected side will be smaller because of reduced sympathetic tone. Move your finger along the skin from forehead to cheek on both sides. In Horner's syndrome the

finger moves less freely on that side of the face, as there is loss of sweating. Look at the patient looking straight at you. Does one eye seem to be deviated? Hold the head still with one hand and hold up the index finger of the other hand about 40 to 50

cms from the eyes. Get the patent to follow your finger to the left and the right, up and down, and to note when diplopia occurs.

If it is not obvious that one eye is failing to move as far as the other, repeat the test but, instead of getting the patient to follow a finger, shine a pen torch in their eyes. The light should be reflected in the centre of the pupil. When diplopia occurs the reflection will appear eccentric in one pupil and that is the side with the pathology.

Check the retina and ascertain that the disc is not obscured by papilloedema. Check the other cranial nerves as described in the separate article Neurological History and

Examination.

Children

In children, especially very small children, getting the child to follow a pen torch is much easier than asking the child to follow your finger and to report diplopia. Another test that is used is the cover test. Get the child to look at your face and then suddenly cover one of their eyes. If there is a squint, the eye with the pathology will move to look directly at you when the other is covered.

Differential diagnosis

There are many possible causes of diplopia and this list is not exhaustive but gives some leads. From the history and examination it should be possible to decide which muscle or muscles are affected. Isolated palsy of just one of the muscles supplied by the oculomotor nerve (III) is unusual.

Common causes

The intracranial course of the abducent nerve (VI) is long and so it is vulnerable at many sites. Hence, abducent nerve paralysis is important but it is a poor localising sign for a space-occupying lesion.

Examination may fail to show any abnormality where fatigue is important, as in myasthenia gravis. About half of all patient with myasthenia gravis will present with ocular symptoms such as diplopia and 50 to 60% will progress to the full disease. A Cochrane review was unable to find good evidence as to the best medical or surgical management.[2]

Do not be too eager to assume hysteria. That is a diagnosis of exclusion. Fluctuating weakness can also occur in encephalopathy and sepsis.[3]

Horner's syndrome is a good lateralising sign but no use to localise a lesion. Inability to look up or down, called vertical gaze palsy, affects both eyes, pupils are often

unequal but fixed and there is usually no diplopia. Think of Parkinson's disease and progressive supranuclear palsy. Inability to look down can lead to falling down stairs.

Multiple sclerosis (MS) often presents with optic neuritis in which there is pain and loss of vision. Diplopia can occur.[4] In MS there will usually be nystagmus and an extensor plantar response too.

Rarer causes

Ophthalmoplegic migraine is a rare condition, thought to represent a variant of migraine; however, clinical presentation and MRI findings have suggested that it might be an inflammatory cranial neuropathy.[5]

Temporal arteritis , also called giant cell arteritis, can present with diplopia.[6]

Sarcoidosis can present as an isolated cranial nerve lesion. Chest X-ray may show bilateral hilar lymphadenopathy (BHL).

Diplopia may be a complication after refractive surgery.[7]

Ocular lesions, including diplopia, can be amongst the presenting features of Creutzfeldt-Jakob disease (CJD), especially new variant CJD.[8]

Chronic progressive external ophthalmoplegia (CPEO)[9] is a rare disorder of slowly progressive paralysis of the extraocular muscles. It is usually bilateral and symmetrical with progressive ptosis followed by external ocular paresis months to years later. Ciliary and iris muscles are spared.

Kearns-Sayre syndrome (KSS)[9] is very rare mitochondrial myopathy related to CPEO but starting before age 20 and with pigmentary retinopathy.

PatientPlus

Examination of the Cranial Nerves

Strabismus Cranial Nerve Lesions Tolosa-Hunt Syndrome

Investigations

Diagnosing which muscles are affected is fairly easy. A final diagnosis is unlikely to be reached in primary care, so referral is usually required. Before referral, check for diabetes if it is not already diagnosed and check blood pressure in case of a vascular disorder.

MRI scan may show a tumour, an area of infarction or even an arterial aneurysm pressing on a nerve. It can also show demyelination.

Chest X-ray may reveal malignancy or sarcoidosis with bilateral hilar lymphadenopathy (BHL).

Management

Clinical management depends upon the cause. In childhood strabismus, surgery may be required but not always. An alternative that shows potential is botulinum toxin.[10]

Driving

People with diplopia must not drive. They may resume driving on confirmation to the licensing authority that the diplopia is controlled by glasses or by a patch which the licence holder undertakes to wear whilst driving. There will probably be permanent revocation of an LGV or PCV licence.

Exceptionally, a stable uncorrected diplopia of 6 months' duration or more may be compatible with driving if there is consultant support indicating satisfactory functional adaptation.

Prognosis

A sixth nerve palsy of vascular or unknown causes typically resolves within 6 to 8 weeks. If resolution does not occur within 2 to 3 months, the condition progresses or, if additional neurological signs or symptoms develop, imaging studies are required.[11]

Provide feedback

Further reading & references

Kanski J. Clinical Ophthalmology, A Systematic Approach, 5th ed. Butterworth Heinemann (2003) University of West Indies ; Anatomy of External Ocular Muscles

1. Rucker JC, Tomsak RL ; Binocular diplopia. A practical approach. Neurologist. 2005 Mar;11(2):98-110.

2. Benatar M, Kaminski H ; Medical and surgical treatment for ocular myasthenia. Cochrane Database Syst Rev. 2006 Apr 19;(2):CD005081.

3. Engstrom JW ; Myasthenia gravis: diagnostic mimics. Semin Neurol. 2004 Jun;24(2):141-7.

4. Chen L, Gordon LK ; Ocular manifestations of multiple sclerosis. Curr Opin Ophthalmol. 2005 Oct;16(5):315-20.

5. Levin M, Ward TN ; Ophthalmoplegic migraine. Curr Pain Headache Rep. 2004 Aug;8(4):306-9.6. Unwin B, Williams CM, Gilliland W ; Polymyalgia rheumatica and giant cell arteritis. Am Fam

Physician. 2006 Nov 1;74(9):1547-54.7. Kowal L, Battu R, Kushner B ; Refractive surgery and strabismus. Clin Experiment Ophthalmol.

2005 Feb;33(1):90-6.8. Armstrong RA ; Creutzfeldt-Jakob disease and vision. Clin Exp Optom. 2006 Jan;89(1):3-9.9. Roy H Sr , Chronic Progressive External Ophthalmoplegia, Medscape, Jun 201110. Crouch ER ; Use of botulinum toxin in strabismus. Curr Opin Ophthalmol. 2006 Oct;17(5):435-40.11. Goodwin D ; Differential diagnosis and management of acquired sixth cranial nerve palsy.

Optometry. 2006 Nov;77(11):534-9.

What Is Myasthenia Gravis? What Causes Myasthenia Gravis?Editor's ChoiceMain Category: Neurology / NeuroscienceArticle Date: 22 Feb 2010 - 0:00 PDT

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In Myasthenia gravis, also known as Goldflam disease, a neuromuscular disease, the muscles under our voluntary control become easily tired and weak because there is a problem with how the nerves stimulate the contraction of muscles. Typically, the muscles around the eyes are affected first, causing the eyelids to droop; some patients also develop double vision.

Muscles we cannot control voluntarily, such as the heart muscles, are not affected.

Myasthenia gravis is an autoimmune disorder, in which circulating antibodies cause weakness by blocking acetylcholine receptors at the post-synaptic neuromuscular junction, inhibiting the stimulative

effect of the neurotransmitter acetylcholine. The disease is treated with immunosuppressants or cholinesterase inhibitors. Although there is no cure, treatment is effective in alleviating symptoms of arm/leg weakness, double vision, drooping eyelids, speech difficulties, chewing, swallowing and breathing. In fact, many people with the disease become completely free of symptoms after treatment.

Symptoms generally worsen with physical activity and improve after resting or a good night's sleep.

Affecting 1 or 2 people in every 10,000, myasthenia gravis is one of the less common autoimmune disorders. Myasthenia gravis (MG) is distinguished from congenital myasthenic syndromes (which have similar symptoms) in that MG responds well to immunosuppressive interventions, while congenital myasthenic syndromes do not.

Myasthenia gravis more commonly occurs in women under 40 years and men over 60. However, it may affect individuals of any age.

According to Medilexicon's medical dictionary:

Myasthenia gravis is " a disorder of neuromuscular transmission marked by fluctuating weakness and fatigue of certain voluntary muscles, including those innervated by brainstem motor nuclei; caused by a marked reduction in the number of acetylcholine receptors in the postsynaptic membrane of the neuromuscular junction, resulting from an autoimmune mechanism."

What are the signs and symptoms of myasthenia gravis?A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor detect. For example, pain may be a symptom while a rash may be a sign.

Muscle weakness severity varies greatly among patients with MG. Sometimes the weakness may be in a localized form, such as just the eye muscles, while in other cases it may be in a severe or generalized form in which many muscles are affected; even those that control breathing.

The main feature of myasthenia gravis is the patient's susceptibility to fatigue (fatigability, fatiguability).

Muscles become progressively weaker during periods of activity Muscles improve after periods of rest Eye muscles - in over 50% of patients the first signs and symptoms involve eye muscles,

including such problems as ptosis (drooping of one or both eyelids), diplopia (double vision), and blurred vision (which may be intermittent). For about 15% of patients only the eye muscles are affected - in such cases their condition is known as ocular myasthenia.

Facial muscles - for approximately 15% of patient the first symptoms involve the throat and face muscle. In such cases individuals may have problems with:

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o Speaking (dysarthria) - depending on which muscles are affected, speech may become soft or nasal.

o Swallowing (dysphagia) - the patient may choke easily, making eating, drinking, swallowing pills harder. Sometimes when the individual tries to drink, the liquid comes out of his/her nose.

o Chewing - muscles used for chewing may weaken considerably during a meal, especially if the person has been eating something hard or chewy, such as a steak.

o Facial expressions - some people may develop an unusual or different smile if certain facial muscles are affected.

Limbs - the arm and leg muscles may weaken, affecting such activities as lifting or walking (the patient's walk may seem like a waddle). When limb muscles are affected, this generally occurs in conjunction with other muscles in the body, such as the throat, eyes or face.

See a doctor if you have problems:

Breathing With your vision Swallowing Chewing Walking

Myasthenic crisis - this is when the respiratory muscles become paralyzed. The patient requires assisted ventilation to stay alive. In patients with already weakened respiratory muscles, myasthenic crises may be triggered by infection, fever, an autonomic nervous system, an adverse reaction to some medication, or emotional stress.

What are the causes of myasthenia gravis? Myasthenia gravis is an autoimmune disease.

What is an autoimmune disease? It is an illness that develops when the person's body tissues are attacked by their own immune system. Our immune system is a complex organization within the body which is designed to find and destroy foreign undesirable invaders, such as bacteria, toxins, or viruses. If somebody has an autoimmune disease their abnormal antibodies, which circulate in the blood, attack desirable things (things that should be protected and not destroyed), such as body tissues.

In the case of myasthenia gravis, antibodies are produced that block or destroy muscle receptor cells, resulting in fewer available muscle fibers. Our nerves communicate with our muscles by releasing neurotransmitters (type of chemicals) which fit precisely into receptor sites on the muscle cells (muscle receptor cells). Consequently, there is inadequate communication between the nerves and affected muscles; the muscles cannot contract properly and become tired and weak very easily - with fewer receptor sites the muscles receive fewer nerve signals.

Why some people's immune systems make antibodies that attack muscle receptor cells is still unknown. Experts say that the thymus gland (located in the upper chest beneath the breastbone) is probably associated with the production of the abnormal antibodies. The thymus gland is large during infancy and small during adulthood; however, a significant number of adult patients with myasthenia gravis have an abnormally large thymus gland. About 1 in 10 myasthenia patients have a non-cancerous tumor of the thymus gland.

We suspect, but are not sure wheter certain medications or viruses might trigger the onset of myasthenia gravis. Symptoms among patient who already have the disease may worsen with some medications, such as beta blockers, calcium channel blockers, quinine, and some antibiotics. Many believe some people have a genetic propensity to developing the disease.

The following are known to make symptoms worse:

Emotional/mental stress Illness Some medications Tiredness Very high temperatures

Diagnosing myasthenia gravisPatients who experience undue weakness which improves with rest have the hallmark signs of myasthenia gravis (MG) - it is a key sign. A GP (general practitioner, primary care physician) may also suspect MG if the patient has impaired eye movements or muscle weakness which is not accompanied by the loss of the ability to feel things. Nevertheless, as MG shares signs and symptoms with some other conditions, the diagnosis will need to be confirmed.

MG patients whose muscles are weak respond well to the application of ice to the affected area. Some doctors may try this initially as they gather data to help them make a diagnosis.

If the patient sees a GP who suspects possible MG, he/she will most likely be referred to a neurologist (a doctor specialized in the human nervous system) to confirm diagnosis. The following diagnostic tests will probably be ordered:

Edrophonium test - this test is usually only ordered when other tests have not yet yielded a conclusive

diagnosis. Edrophonium chloride (Tensilon, Reversol) or neostigmine (Prostigmin) is injected into a vein - the drug clocks the breakdown of acetylcholine by cholinesterase (cholinesterase inhibitors) and temporarily increases the levels of acetylcholine at the neuromuscular junction - put simply, edrophonium bocks an enzyme that breaks down acetylcholine, the chemical that transmits signals from the nerve ending to the muscle receptor sites. Some patients may experience a brief period in which muscle weakness is relieved, especially those with weakness in the eye muscles.

Blood tests - the aim here is to identify certain antibodies:

One test is for antibodies against the acetylcholine receptor. This test has a reasonable sensitivity of 80% to 90%. However, it may be as low as 50% in ocular myasthenia patients (those with just eye muscle weakness).

Some MG patients without antibodies against the acetylcholine receptor have antibodies against the MuSK protein. A blood test may detect those antibodies.

In some rare cases, when the doctor may want to rule out Lambert-Eaton syndrome, the blood test will attempt to detect antibodies against a voltage-gated calcium channel.

Repetitive nerve stimulation - electrodes are attached to the skin over the affected muscles. Small electrical pulses are sent through the electrodes to measure how well the nerves send a signal to the muscle. The electrical pulses will be applied several times to determine whether signals get worse when the muscle is tired.

Single-fiber electromyography (EMG) - this measures the electrical activity that flows between the brain and the muscle. A very fine wire electrode is inserted through the skin, into the muscle. Some patients may find this test uncomfortable. In a more precise version of this test, called single-fiber EMG, a single muscle fiber is tested.

Imaging scans

A chest X-ray is commonly performed, as it may point towards alternative diagnoses, such as Lambert-Eaton due to a lung tumor, and comorbidity (the presence of one or more disorders/diseases in addition to a primary disease/disorder, or the effect of such additional disorders or diseases).

A CT (computed tomography) or MRI (magnetic resonance imaging) scan may be performed to identify a thymoma (tumor in the thymus gland). CT or MRI scans are better at detecting thymomas than X-rays.

Pulmonary function test (spirometry) - the aim here is to determine whether the patient is breathing adequately. The forced vital capacity (the maximum amount of air a person can expel from the lungs after a maximum inspiration) may be periodically measured so as not to miss a gradual worsening of muscular weakness in the lungs. MG patients with severe symptoms are at risk of respiratory failure due to exhaustion of the respiratory muscles. Respiratory failure is when there is inadequate gas exchange by the respiratory system, with the result that arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges.

Muscle biopsy - this is only done if the diagnosis is in doubt and a muscular condition is suspected. A needle or small incision is used to remove a small sample of muscle. The patient will receive a local anesthetic.

What are the treatment options for myasthenia gravis? There is no cure for myasthenia gravis. However, most therapies (treatments) are very effective in controlling symptoms. In fact, the majority of MG patients who undergo treatment become completely free of symptoms, and can lead normal (or near normal) lives. In some cases, all that is required to relieve symptoms are adequate sleep and rest.

Cholinesterase inhibitors - such as pyridostigmine (Mestinon) block the action of the chemical that normally makes the muscle relax after it has contracted - they improve communication between nerves and muscles. This medication is very effective for patients with mild MG symptoms; helping the affected muscles contract properly and maintain good strength. Some side effects may include nausea and/or stomach cramps.

Steroids or Immunosuppressants - prednisolone (a steroid drug) or azathioprine (an immunosuppressant drug) may alter the body's immune system and lower the production of antibodies that cause MG. It usually takes about four weeks for the effects of steroids to appear, while azathioprine may take from three to six months.

These medication are usually very effective; either significantly reducing symptoms or getting rid of them altogether.

This type of medication is usually only given to patients who could not have their thymus gland surgically removed, or those whose symptoms did not improve after surgery.

Removal of the thymus gland (thymectomy) - about 15% of MG patients have a tumor in their thymus gland. In such cases a thymectomy is required - the gland is surgically removed.

It is unclear whether the risks of removing the thymus gland outweigh the benefits for MG patients who don't have a tumor. If the patient's symptoms are mild, only involve the eyes, or if he/she is over 60 years of age most doctors will not recommend surgery.

Surgically removing the thymus gland improves symptoms for over 70% of MG patients, and eliminates symptoms completely for 30%. Improvements gradually appear over a period of 12 months; in some cases this may take longer (up to 3 years).

Plasmaphoresis and immunoglobulin therapy - this therapy, which is given in hospital, is used for patients with severe symptoms; specifically patients with life-threatening breathing or swallowing problems.

Plasmaphoresis - the procedure depletes the body of blood plasma without depleting the body of its blood cells. Blood is removed from the body, the plasma is separated from the cells, the cells are then suspended in saline (or a plasma substitute or donor plasma), and the reconstituted solution is returned to the patient. Put simply - the blood is taken out of the patient, the abnormal antibodies that cause MG are removed, and the blood is placed back into the patient.

Intravenous immunoglobulin therapy - normal antibodies that alter the way the immune system acts are injected into the patient.

Although extremely effective with rapid results, the benefits last no longer than a few weeks. This treatment is a short-term one, used only if the patient is extremely ill.

What are the possible complications of myasthenia gravis? Myasthenic crisis - the respiratory muscles become so weak that the patient cannot breathe properly. This is potentially a life-threatening complication and requires emergency treatment with mechanical breathing assistance. Plasmaphoresis and immunoglobulin therapies, as well as medications help patients recover.

Thymus tumors - approximately 15% of MG patients have a tumor in the thymus gland. In most cases it is a benign (non-cancerous) tumor. This is treatable.

Thyroid problems - the thyroid gland secretes hormones that regulate our metabolism; it is located in the neck. MG patients may have either an overactive thyroid (hyperthyroidism) or an underactive one (hypothyroidism).

Lupus - an autoimmune disease where the body's immune system becomes hyperactive and attacks normal, healthy tissue. This results in symptoms such as inflammation, swelling, and damage to joints, skin, kidneys, blood, the heart, and lungs.

Rheumatoid arthritis - a chronic (long lasting), progressive and disabling auto-immune disease condition that causes inflammation (swelling) and pain in the joints, the tissue around the joints, and other organs in the human body. Rheumatoid arthritis usually affects the joints in the hands and feet first, but any joint may become affected. Patients with rheumatoid arthritis commonly have stiff joints and feel generally unwell and tired.