Wednesday, May 18, 2011

Oculomotor nerve palsy - Diagnosis

Topographic diagnosis of oculomotor nerve paralysis
- The orbit can be affected only extrinsic muscles, without being affected oculomotor nerves. Common causes that can affect muscles are traumatic orbital hematoma, orbital tumors, myasthenia, miozitele, exoftalmiile cause of malignancy.Oculomotor nerve lesions in the orbit are given most frequently by trauma and tumors.
- The gap sphenoid oculomotor nerves are in the vicinity of the ophthalmic trigeminal nerve wreath and this region leads to impaired sensory-motor ophthalmoplegic. Common causes of damage are sphenoid slot: sinusitis, osteoperiostitele, malignant tumors. The most commonly injured nerve VI is.
- In the middle portion of the cavernous lodge oculomotor nerve palsy causes are internal carotid artery aneurysms or cavernous sinus thrombophlebitis. The sphenoid bone fracture meets a bilateral paralysis of VI nerve sudden. If a VI nerve palsy is suspected onset of a slow expansion of the internal carotid artery aneurysm. The cavernous sinus, the nerve can be affected VI and carotid cavernous fistula, tumor like pituitary adenoma, meningiomas, nasopharyngeal carcinoma, herpes infections. In the middle portion of the cavernous lodge oculomotorilor paralysis nerve paralysis associated with maxillary and ophthalmic nerve, and signs of pituitary dysfunction.
- Lodge in the posterior cavernous nerve VI ascending portion crosses the carotid artery, nerve and carotid artery is positioned between the Gasser ganglion. If an internal carotid artery aneurysm in this area appears syndrome "broken the previous hole." This syndrome is characterized by VI cranial nerve palsy and trigeminal nerve (cranial nerve V), plus signs of sympathetic suffering pericarotidian. Can appear as Claude Bernard-Horner syndrome associated with trigeminal neuralgia.
- Rock the temporal bone in the tip region, abducens nerve (nerve VI) is commonly injured by fractures, osteitis of rock and temporal mastoiditis. In this region, nerve damage and paralysis is accompanied VI wreath of ophthalmic trigeminal nerve, causing Gradenigo syndrome. This syndrome is characterized by deafness, pain and paralysis of the ipsilateral abducens.
- In the subarachnoid space, which it crosses the oculomotor nerves, the most frequent causes that injure these nerves are intracranial hypertension, which causes paralysis most often bilateral VI nerve, intracranial hypotension by lumbar puncture, anesthesia, or spontaneous dural extravasation cerebrospinal fluid, with the effect of moving the brainstem, near convexity subdural hematoma can cause paralysis of the oculomotor nerves indirectly by brain compression herniaza hiatus gap in the cerebellum, hematoma of the skull base through mass direct effect and can cause paralysis oculomotorilor other cranial nerves. Other causes leading to the oculomotor nerve palsy are meningitis and subarachnoid space inflammatory states during otomastoiditelor meningeene. Meningitis syphilitic skull base especially damaging cranial nerve III. Bilateral VI cranial nerve palsy and oculomotor nerve palsy parceling of others is also found in cerebrospinal meningitis. In tuberculous meningitis in children most frequently injured nerve III tuberculous meningitis in adults usually injures nerve VI. In posterior fossa tumors is frequently injured nerve VI.
Oculomotorilor paralysis during brain stem syndromesWhen the lesion is apparent between the nuclei and the origin of the nerves in the brainstem, through gaining pyramid horses appear before crossing alternate hemiplegiile: Weber syndrome, Millard-Gubler syndrome.Weber syndrome consists of oculomotor nerve palsy with homolateral hemiplegia controlaterala, appearing in the peduncle lesions.Millard-Gubler syndrome is characterized by a cross paralysis, controlaterala homolateral limbs and face, being the result of nerves VI and VII and the corticospinal tract. It usually occurs from acute Pontin, being incriminated anterior-inferior cerebellar artery.Oculomotor nerve palsy is common feature in case of nuclear paralysis, that is due to parceling nucleus (which consists of several cell groups).
The differential diagnosis of blepharospasm is running a VII nerve palsy. It is distinguished from true ptosis in that it resists attempts to lift the eyelid. It is associated with strabismus or diplopia.Congenital strabismus is usually related to a refractive defect and diplopia is not met in this case. Myasthenia gravis may lend itself to confusion with oculomotor paralysis especially in its early stages and remains a long time when eye muscle area, but in this case pupillary muscles are untouched.

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