anatomy - دانشکده پزشکی اصفهانmed.mui.ac.ir/clinical/ophthalmology/anatomy.pdf ·...

Anatomy

Orbital facia

Periororbital faciaOrbital septumBulbar faciaMuscular facia

Physiology of symptoms

1) Proptosis ( exophthalmos)PseudoproptosisAxialNon axialPulsatingPositionalIntermittent

2) Conjunctival and eye lid edema &redness

3) Diplopia4) Retinal edema and venous engorgement5) Choroidal fold6) Visual loss

Diagnosis studies

1) Imaging CT & MRI2) Ultrasonography3) Venography4) Angiography5) Radiography6) Fin – needle aspiration

Disease & disorders of theorbit

Inflammatory disorders1) Grave's ophthalmopathy2) Pseudo tumor

Orbital infections

1) Orbital cellulites2) Mucormycosis

Grave's ophthalmopathy

The most common cause of unilateral andbilateral orbital proptosis in adult is grave'sdiseaseSome degree of ophthalmopathy – usually mild– occurs in a high percentage of hyperthyroidpatientsSevere infiltrative orbital myopathy withsignificant proptosis and restricted motilityoccurs in about 5% of cases of grave's disease

This severe form can also occur withhypothyroidism or with no detectablethyroid abnormalityThyroid ophthalmopaty is thought to bean autoimmune diseaseIt is often seen in autoimmune(Hashimotos ) thyroiditis( antithyroglobulin – antimicrosomal )

Clinical findings1) Protosis with lid retraction ( corneal

exposure)Ocular myopathy usually begins withinfiltration & edema of the rectus muscles( fibrotic – restricted )

2) Diplopia ( usually ) begins in the upperfield of gaze

3) Compressive neuropathy early signsinclude an afferent pupillary defect –impairment of color vision and slight lossvisual acuity & blindness

TreatmentThe goal of treatment of grave'sophthalmopathy is initially maintaincorneal protection ( lubricant )As the disease progresses it became toaddress the problems of diplopiaproptosis & compressive opticneuropathy

1) Manage the thyroid status( endocrinologist)

2) Oral corticosteroids ( 60- 100 mg/d or 1-2mg/kg)

3) Surgical decompression of the orbit (neuropathy unresponsive to medicalmanagement )

4) Orbital radiation ( active phase )5) Surgery ( strabismus – lidretraction ( eye lid )

Pseudotumor

A frequent cause of proptosis in adultand childrenDiffuse inflammation of any orbitalstructure( myositis – dacryoadenitis –lymphogranoloma ) ( Lymphocytesfibroblasts – histiocytes plasma cellsPseudotumor : is usually unilateral

Differential diagnosis

1) Grave's disease2) Orbital lymphoma

Treatment

1) Systemic NSAIDS2) Systemic corticosteroid3) Radiation4) Surgery often exacerbates the

inflammatory reactions

Orbital infections

1) Orbital cellulites2) Mucormycosis

Orbital cellulitis is the most commoncause of proptosis in childrenImmediate treatment is essentialOrbital cellulitis frequently led toblindness

The orbit is surrounded by paranasalsinuses and part of their venous drainageis through the orbitMost cases of orbital cellulitis a viasefrom extension of sinusitis through thethin ethmoid bones

Organism

1) Hemophilus influenzae2) Streptococcus pneumonia3) Other streptococcoci and staphylococci

Clinical findingsOrbital cellulitis : preseptal -postseptalBoth present with edema , erythema ,hyperemia pain and leukocytosis

Postseptal orbitalcellulitis

ChemosisProptosisLimitation of eye movementReduction of vision

Extention to the cavernous sinus maycauses bilateral involvement of cranialnerves II- VI with severe edema andseptic feverErosion of the orbital bones may causebrain abscess cells and meningitis

Differential diagnosis

1) RhabdomyosarcomaPseudotumorGrave's disease

TreatmentAs soon as nasal conjunctival and bloodcultures are obtainedIntravenous antibiotics ( gram – negativeand gram positivesHot compressesNasal decongestants andvasoconstrictorsMRI is useful in deciding when andwhere to drain an orbital abscessEarly consultation whit otolaryngologist

Mucormycosis

Diabetics and immunocompromisedpatients have a propensity to developsevere and often fatal fungal infections ofthe orbitThe organisms are of the zygomycetesZygomycetes have a tendency to invadevessels and create ischemic necrosis( muscle , bone and soft tissue )

Clinical findings

Pain and proptosisNecrotic area of mucosa of the nose andpalate

Without treatment , the infectiongradually erodes in to the cranial cavityresulting in meningitis brain abscess anddeath

Treatment

1) Correction of the underlying disease2) Surgical debridment3) Amphotericin B intravenously

recurrences are common

Cystic lesions involvingthe orbit

-Dermoid-Epidermoidcyst-DermolipomaSinusmucocele-Meningocele

Vascular abnormalitiesinvolving the orbit

Arteriovenous malformationCarotid artery – cavernous sinus fistula

Primary orbital tumors1) Capillary hemangioma2) Cavernous hemangioma3) Lymphangioma4) Rhbdomyosarcoma5) Neurofibroma6) Optic nerveglioma

Lacrimal gland tumor

LymphomaHistocytosis

Metastatic tumors

Metastatic tumors reach the orbit byhematogenous spread since the orbit isdevoid of lymphaticsMetastasis are usually from the breastwomenMetastasis are usually from lung in men

The most common metastatic tumor isneurblastoma in children