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