Thyroid Eye Diseaseaka Thyroid Associated Ophthalmopathy

Etiologi Berhubungan dengan penyakit-penyakit kelenjar tiroid

TirotoksikosisGraves Disease Goiter toksik noduler

HipothyroidHashimotos Disease

PathologyActivated T cells infiltrate orbital contentsand stimulate fibroblasts, leading to:

Enlargement of extraocular musclesCellular infiltration of interstitial tissuesProliferation of orbital fat and connective tissue

Enlargement of extraocular musclesThe stimulated fibroblasts produce glycosaminoglycans (GAGs) which cause the muscle to swellMuscle size may increase by up to 8 timesThe swollen muscles occupy orbital space and can compress the optic nerveThese swollen muscles can cause a forward propulsion of the globe (proptosis) so that the eyelids do not cover well and eyes dry out, causing exposure keratopathySwollen musclesCompression of optic nerve at apex of orbitSwollen muscle (lateral rectus)Swollen muscle (medial rectus)

Cellular infiltration of interstitial tissuesLymphocytes, plasma cells, macrophages and mast cells infiltrate extraocular muscles, fat and connective tissueLymphocyte cuff

Pathololgy (contd)Causes degeneration of muscle fibresLeads to fibrosis of the involved muscle

Build up of fibrous tissue

This restricts its movement and causes diplopia (double vision) in the direction of gaze which is restrictedRLWhen looking up, the Right eye fails to elevate, due to muscle tethering

Two Stages of DevelopmentActive inflammation:Eyes red and sore yearsCosmetic problemRemission within 3 years in most patients10% patients develop serious long-term ocular complicationsQuiescent stage:Eyes whitePainless motility defect maybe presentSeverity may range from being nuisance to blindness (2 exposure keratopathy or optic neuropathy)

Five Main Clinical ManifestationsSoft Tissue InvolvementEyelid RetractionProptosisOptic Neuropathy / Exposure KeratopathyFibrosed Muscles

KlasifikasiKlas 0 N o physical signs or symptomsKlas 1 O nly signs, no symptom (hanya stare, lidlag, upper eyelid retractionKlas 2 S oft tissue involvement (palpebra bengkak, kemosis dan lain-lain) 90%Klas 3 P roptosis (> 3mm dari batas atas normal) 30%Klas 4 E xtraocular muscle involvement (sering dengan diplopia) 60%Klas 5 C orneal involvement 9%Klas 6 S ight loss (karena saraf optikus terlibat) 34%

Soft Tissue Involvement - SymptomsVariable grittinessPhotophobiaLacrimation - watery eyes

Soft Tissue Involvement - SignsPeriorbital and lid swellingConjunctival hyperaemiaSensitive sign of disease activityChemosis (oedema of the conjunctiva)Severe cases: conjunctiva prolapses over lower eyelid

Soft Tissue Involvement - RxFrequently unsatisfactory, may be of some benefitTopical Rx lubricants (artificial tears & ointment) reduce irritation caused by conjunctival inflammation and mild corneal exposureElevating the head end of bed during sleep may decrease periorbital oedema. Diuretics given at night may also reduce the morning accumulationTaping of eyelids at night may be useful for mild exposure keratopathy

Eyelid RetractionRetraction of both upper and lower eyelids occur in 50% of patientsNormally, upper eyelid rests about 2mm below limbus, with lower eyelid resting at the inferior limbusWhen retraction occurs, the sclera (white) can be seenCauses cosmetic problemsPathogenesis not clearMay be due to contraction of the levator muscle by fibrosis, or be chemically induced by high thyroid hormone levelsIf persists when disease is inactive, can be helped by eye lid surgery

Eyelid Retraction Clinical FeaturesClinical signs:Lid retraction in 1 (front) gazeLid lag i.e. delayed descent of upper lid in downgazeStaring appearance of the eyes

Eyelid Retraction - RxMild eyelid retraction does not require Rx, in 50% of cases, there is spontaneous improvementRx of associated hyperthyroidism may also improve lid retractionMain indications are exposure keratopathy and poor cosmesisTreatment is surgical if required, when both the eyelid retraction and thyroid are stable

ProptosisProptosis is axialTED is the most common cause of both bilateral and unilateral proptosis in adultsProptosis is uninfluenced by Rx of hyperthyroidism and is permanent in 70% of casesSevere proptosis prevents adequate lid closure, and may lead to severe exposure keratopathy and corneal ulceration

Proptosis - RxSystemic steroids to reduce inflammationLow dose radiotherapySurgical decompression: This is where one or more walls of the orbit are removed causing an increase in space and relief of the proptosis.

Optic NeuropathySerious complication affecting about 5% of patientsCaused mainly through direct compression of the optic nerve or its blood supply by enlarged and congested rectus muscles at the orbital apexMay occur in the absence of proptosisCan cause severe but preventable visual impairment

Optic Neuropathy Clinical FeaturesAn early sign is decreased colour visionSlow progressive impairment of visual acuityVisual defects, especially central scotomasOptic atrophy in chronic advanced cases

Optic Neuropathy - RxDepends on severityInitial RX by systemic steroids and/or radiotherapyOrbital decompression is considered if above is ineffective or optic nerve severely involved

Ocular Motility ProblemsBetween 30% and 50% of dysthyroid patients develop eye movement problemsThe diplopia caused by this may be transient, but in many, it is permanentOcular motility is restricted by oedema in the infiltrative stage and fibrosis during the fibrotic phaseA defect in elevation is most common due to fibrosis of inferior rectus tethering eye

Rx of Ocular Motility ProblemsSurgery is usually considered if there is diplopia in primary gaze or reading positionDiplopia must have been stable for about 6 months Rx is by muscle surgery, with the aim of producing binocular vision when looking forward, and good cosmetic resultBotulinum toxin injection (Botox) to relax muscles may be useful in selected cases

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