Download MBBS Ophthalmology PPT 17 Thyroid Ophthalmopathy Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Ophthalmology PPT 17 Thyroid Ophthalmopathy Lecture Notes


Causes of proptosis

and

Thyroid Ophthalmopathy

Department of Ophthalmology

1

Acknowledgement

? UptoDate: Graves' orbitopathy: Diagnosis and Treatment.
? Cummings Otolaryngology. Girod, Douglas A.; Wemer, Richard D.;

Larsen, Christopher G. Published January 1, 2015. ? 2015.

? Endocrinology : Adult and Paediatric. Burch, Henry B.; Bahn, Rebecca

S.. Published January 1, 2016. ? 2016.

? Some of the images used were taken from eyetext.net

2
Learning Objectives

? At the end of this class the students shal be able to :
? Enumerate the common causes of proptosis

? Understand the pathogenesis and clinical features of thyroid eye disease.

? Enumerate and elicit the common eye signs of thyroid ophthalmopathy.

? Have a basic understanding of principles of management of the disease.

3

Question

? A 44-year-old female patient presents with bilateral protrusion of the

eyeball along with retraction of the eyelids and lid lag on downgaze.

What is her most likely diagnosis?

? a. Grave's disease
? b. Orbital pseudotumor
? c. Orbital cellulitis
? d. Orbital varices

4


Proptosis

? Forward displacement or protrusion of

eyebal .

? Protrusion of globe >21mm or atleast 2mm

asymmmetry between the two eyes is

abnormal.

? Measured by Hertel's Exophthalmometer

? Differentiate from pseudoproptosis or

apparent eyebal protrusion


High myopia

Lid retraction

5

Proptosis

? Axial and non-axial(Abaxial)
? Unilateral and Bilateral proptosis

Inflammation: Thyroid

Congenital: Dermoid Cyst

orbitopathy

Traumatic: Orbital hemorrhage

Sarcoidosis

Inflammatory: Orbital cellulitis

Neoplasia: Lymphoma

Orbital psudotumour

Leukaemia

Vascular: Orbital varix

Vascular malformation:

Cystic: Orbital cysticercosis

Arterio-venous shunts

Tumours of the orbit

Lacrimal lesions: Sjogren's

syndrome

6
Introduction of Thyroid eye disease

? Thyroid eye disease is an autoimmune disease producing symptoms
related to inflammation, accumulation of fluid in the orbit and also to
adipogenesis raising intra-orbital pressure.
? Synonyms
? Graves' ophthalmopathy/orbitopathy (GO)
? Thyroid eye disease (TED)
? Thyroid associated ophthalmopathy (TAO)
? Dysthyroid ophthalmopathy

7

Epidemiology

? Prevalence of thyroid ophthalmopathy = 0.4%
Women > Men
? But severity greater in men
? Bimodal age distribution ? Peak incidence in fourth and sixth decades

of life

? May be exacerbated by stress and smoking
? Most common cause of exophthalmos
? >50% of cases with Graves' disease have eye involvement

8
Etiology

? Graves' hyperthyroidism (90%)

? Hypothyroid Hashimoto's thyroiditis

? Euthyroid subjects with no current or past evidence of thyroid

hyper or hypofunction (so called euthyroid Graves' disease).

? In patients with Grave's disease, eye signs may precede, coincide with

or follow the hyperthyroidism

9

Risk factors

? Smoking (strongest modifiable risk factor)

? Family history

? Monozygotic twins

10


Pathogenesis

? Autoimmune process manifesting as:

? Extraocular muscle myositis

? T-cel inflammatory infiltrate

? Fibroblast proliferation

? Glycosaminoglycan overproduction

? Increase in soft tissue mass within

bony orbit due to extraocular muscle

enlargement, increased orbital fat and

connective tissue

? Later in disease, inflammatory

infiltrate replaced by widespread

fibrosis

? "Inactive" phase occurs after 8months

to 3years

11

Pathogenesis

Pleomorphic cel ular infiltrate

Increased secretion of GAG's

Osmotic imbibition of water

Muscular swel ing upto 8 times

Subsequent degeneration leading to

fibrosis

12


Histology

Fluid and inflammatory cells separate the muscle bundles of the
extraocular muscles

13

Histology

Lymphocytes, plasma

cells, macrophages

and mast cells

infiltrate extraocular

muscles, fat and

connective tissue

14


Histology

Degeneration

of muscle fibres

Leads to fibrosis

of the involved

muscle

15

Natural History of Thyroid Eye Disease

? Progressive phase lasting for up to 18 months
? Stable (inactive) phase

16


Course of disease

? Inflammatory/active phase Fibrotic/inactive phase

Clinical course of orbital disease proceeds independently of thyroid gland

dysfunction and treatment

17

Symptoms

? Foreign body sensation
? Epiphora (tearing)
? Photophobia
? Bulging of eyes
? Puffiness of eye lids
? Diplopia
? Visual loss

18


Signs

? Eyelid Retraction

? Proptosis

? Restrictive Myopathy

? Soft Tissue Involvement

--- Conjunctival hyperaemia, lid oedema and chemosis

? Optic Neuropathy

19

Clinical signs in TED

? Facial signs
? Joffroy's sign-absent creases

in the forehead on superior

gaze

20




Clinical eye lid signs in TED

? Kocher's sign- staring appearance

? Von Graefe's sign- lid lag on downgaze

? Dalrymple's sign- lid retraction

? Stel wag's sign- incomplete & infrequent blinking

? Enroth 's sign- edema of lower lid

? Griffith's sign- lower lid lag on upgaze

21

Soft Tissue Inflammation

? Often the earliest sign.

Consists of
? periorbital edema
? conjunctival hyperemia
? chemosis

22


Eyelid retraction

? Also cal ed Dalrymple's sign.

? Normal y, upper eyelid- 2mm below limbus

? Lower eyelid-inferior limbus

? When retraction occurs, the sclera (white) can

be seen

Occurs due to :

? Increased sympathetic stimulation of M?ller's

muscle by thyroid hormone

? Overaction of the levator muscle contracting

against a tight inferior rectus

23

Proptosis

? Usually (90%) bilateral
? Thyroid eye disease is the most common

cause of unilateral and bilateral

proptosis in adults

? Axial
? Resulting from enlargement of the

extraocular muscles and adipose

tissue, as well as orbital fat
? Infiltration of orbital tissues by GAGs and

leukocytes

24


Proptosis

? It does not respond to hyperthyroidism

treatment

? Is permanent in 70% of cases.
? Severe proptosis prevents adequate lid

closure

? May lead to severe exposure

keratopathy and corneal ulceration.

25

Restrictive Myopathy

? Eye movements are restricted due to oedema in extraocular muscles
during infiltrative stage and subsequent fibrosis.
? Despite expansion of the extraocular muscles , the muscle fibres
themselves are normal.
? IR>MR>SR>LR
? Pressure exerted by a fibrotic inferior rectus muscle on the
globe may cause a spike in intraocular pressure during upgaze.

26


Dysthyroid Optic Neuropathy

(DON)

Optic neuropathy as result of optic nerve compression

from enlargement of extraocular muscles

27

WERNER?S CLASSIFICATION - NOSPECS

? Class 0: No signs or symptoms
? Class 1: Only signs (lid retraction, stare ? lid lag)
? Class 2: Soft tissue involvement
? Class 3: Proptosis
? Class 4: Extraocular muscle involvement
? Class 5: Corneal involvement
? Class 6: Sight loss (optic nerve involvement)

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EUGOGO classification

? Mild : eyelid swelling , lid retraction, proptosis

? Moderate-Severe : Active disease (EOM dysfunction, diplopia ,

proptosis >25 mm)

? Very severe : Compressive Optic Neuropathy , Corneal exposure

(needs emergent surgery)

29

VISA classification

? V (Vision) , I (inflammation), S (Strabismus) , A (Appearance)
? Vision/CON
? Inflammation/Congestion : based on documented change of

inflammation rather than absolute value

? Strabismus/Motility : measuring ductions and alignments
? Appearance/Exposure
? Score of 5 or more --> Active disease or progression (Consider

Steroids)

30
Differential Diagnosis

? Orbital tumors (primary or metastatic)
? Orbital pseudotumor
? Wegener's granulomatosis
? Orbital infection
? Carotid-cavernous sinus fistula

31

Diagnosis

? Characteristic eye findings
? Thyroid dysfunction
? Imaging

32
Blood investigations

? Highly sensitive & specific -- T4(thyroxine) + TSH or serum TSH

? If eye findings associates with euthyroid Graves' disease ?

? Thyroid peroxidase antibody

? Antibody to thyroglobulin

? Others

? Free T4 index

? Thyroid-stimulating immunoglobulin

? Antithyroid antibodies

? Serum T3

33

Radiological Evaluation

? Usually employed if cause of exophthalmos is unclear (ie. normal

thyroid lab studies, or history/physical examination inconsistent with

thyroid disease)

? Also to determine optic nerve involvement if not obvious by

fundoscopic examination.

? Distinct sparing of muscle tendons in thyroid ophthalmopathy.

34


Radiological Evaluation

? CT scan is currently the imaging study of choice.
? MRI is sensitive for showing compression of the optic nerve.

? Neuroimaging usually reveals
? Thick muscle belly with tendon sparing
? Usually IR & MR
? Bilateral muscle enlargement is the norm
? Unilateral cases usually represent asymmetric involvement rather

than normality of the less involved side

35

Axial and coronal C.T. scan in Thyroid eye disease

36


? Non-contrast enhanced coronal orbital CT scan most helpful to assess

size of extraocular muscles.

37

Axial CT of orbits

demonstrating

medial rectus

enlargement

38
Management

? T ? Tobacco abstinence
? E ? Euthyroidism
? A ? Artificial tears
? R ? Referral
? S ? Self help groups

39

Medical Management of Hyperthyroidism

? Anti-thyroid drugs : thinoamides (PTU) , carbimazole , methimazole.

? Thionamides inhibit synthesis of thyroid hormones.

? Need 6-8 weeks to achieve euthyroid state

? Side effects of anti-thyroid drugs
Skin rash , urticarial , arthralgia , fever

40


Treatment of mild Thyroid eye disease

41

Symptomatic treatment

? Artificial tears

? Eye shades

? Raise head of bed at night

? Diplopia can be managed with prism glasses

? Eventually may require strabismus surgery

? Conserve useful vision

? Minimize amount of exposed cornea

? May require lid surgery

? Treat optic neuropathy

42
Selenium

? 200 microgram/day for 6 months
? For Mild disease

? Antioxidant effect
? Immunomodulatory effect : reduce thyroid autoantibodies
? Reduces severity of disease and improve quality of life

43

Corticosteroids

? Intravenous , Oral
? IV pulses are more effective and have less side effects
? IV dose (max 8 grams) : 500 mg weekly for 6 weeks and then 250 mg
weekly for 6 weeks
? Relapse is common (20%)
? Steroid response is evident usually 2-4 weeks later
? Moderate to severe TED : 71% respond to IV steroid vs 51% with oral
? IV steroids for compressive Optic Neuropathy

44
Rituximab
? Chimeric mono-clonal antibody targets CD20

? CD20 is expressed on more than 95% of B cells and plasma cells

? RTX depletes 95% of mature B cells , blocks Ab production , and
decreases inflammatory cytokine release

? For steroid-refractory disease

? Side effects : Allergic reaction (mild) PML (severe)

45

Orbital Radiation

? Mechanism : lymphocyte sterilization, destruction of tissue
monocytes
? 20 Gy in 10 divided sessions over 2 weeks
? May have a role in patients with TED who have restricted ocular
motility or active disease
? Some studies have shown benefit (controversial)
? More suited for patients > 35 years of age
? Contra-indicated in pre-existing retinopathy (diabetes , hypertensive)

46
Botulinum Toxin

? Neurotoxin , inhibits acetylcholine release
? For upper lid retraction (transconjunctival , transcutaneous route)
? Effect on Muller's muscle and LPS
? Side effects of Botox : bruising , ptosis and diplopia

47

Orbital Decompression for TED

? Decompression usually in stable phase of disease.

? Indications

? compressive optic neuropathy

? severe exposure keratopathy

? Post-operative complications (diplopia, vision loss)

? Outcome is variable : degree of fibrosis , fat expansion , bone

available, duration of optic neuropathy.

? Decompression --> Muscle Surgery --> Lid surgery

48
Strabismus Surgery for TED

? In the stable phase with stable alignments for 6 months
? Aim is single binocular vision in primary and reading position
? Typically involves release of the restricted muscle by recession rather

than resection

? Conjunctival dissection is challenging
? Use of adjustable sutures is strongly recommended due to the

variability in fibrosis, resulting in unpredictable results.

? Oblique surgery can increase area of single binocular vision

49

Eye lid surgery

? The most common indication for lid surgery is upper lid retraction.

? Graded Muller's and levator aponeurosis weakening.

? Lower lid lengthening is indicated in lower lid retraction.

50


Psychological Impact of TED

? Disfigurement/altered facial appearance
? Misinterpretation as hostile or angry
? Almost 50% of TED suffer depression and/or anxiety
? 90% of TED have appearance concerns (young females)
? 44% have self-confidence issues
? Multidisciplinary approach (psychiatric included)
? Support groups

51

52
Conclusion

? Activation of thyrotropin receptor on orbital fibroblast by circulating
autoantibodies plays a primary role in development of thyroid
ophthalmopathy.
? Management is based on accurate assessment of both severity and
activity of disease.
? Immunosuppressive therapy is reserved for patients with clinically
active moderate to severe disease

53

Question

? Which of the following statement is correct regarding Thyroid eye

disease?

? a. It cannot be present in the euthyroid patient.
? b. The earliest sign is loss of sight due to optic neuropathy
? c. The lateral rectus muscle is least commonly involved.
? d. There is only unilateral involvement in the disease.

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Thank You

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This post was last modified on 07 April 2022