- Clinical science
The orbital cavity (eye socket) is the bony cavity that encloses the bulb and accessory organs of the eye, including the ocular muscles, lacrimal glands, nerves, vessels, and retrobulbar adipose tissue. Diseases of the orbital cavity include Graves ophthalmopathy, orbital cellulitis, rhabdomyosarcoma, and lacrimal sac disorders. Typical symptoms associated with these diseases include exophthalmos and diplopia. Treatment differs according to the underlying disease and includes conservative measures (antibiotics), surgery, radiotherapy, and chemotherapy.
are discussed in a separate learning card.
- Definition: Graves ophthalmopathy or orbitopathy (GO) (also known as thyroid-associated orbitopathy or ophthalmopathy, TAO) is an autoimmune condition that is generally associated with
- Sex: ♀ > ♂
- Risk factors; : family history of Graves disease and tobacco smoking
- TSH autoantibodies are present in the orbital cavity; (eye socket) → bind TSH receptor antigen (autoimmune reaction) on cells; → lymphocytic infiltration into the orbital tissues → inflammation and release of cytokines from CD4+ T cells → stimulates fibroblasts to secrete glycosaminoglycans (hyaluronic acid), which also pulls water into the interstitial space (osmotic effect); → expansion of retro-orbital tissue due to increased fluid in extraocular muscles, lymphocytic infiltration, and adipogenesis
- Exophthalmos : can be unilateral or bilateral, often asymmetric. Retropulsion (palpation of the globe while the eyelid is closed) enable adequate examination.
- Ocular motility disturbances
Lid retraction, also known as “thyroid stare”
- Dalrymple sign: retraction of the upper eyelid with visible sclera and extended palpebral fissure
- Von Graefe sign: lagging of the upper eyelid on downgaze (may occur with Grove sign: resistance to pulling the retracted upper lid down)
- Stellwag sign: infrequent and incomplete blinking (rare)
- Lagophthalmos → keratitis (occurs with insufficient blinking)
- Joffroy sign: absent forehead creases during superior gaze
- Conjunctival injection and chemosis
- Ocular discomfort (pain or pressure)
- Patient may be hyperthyroid, euthyroid, or hypothyroid.
- Laboratory analysis: ↓ TSH and ↑ free T3/T4; (to diagnose of hyperthyroidism), ↑ TSH receptor antibodies, which are specific and sensitive to Graves disease but not widely available
- CT: confirmatory test that shows exophthalmos, increased fat density and inflammation and enlargement of extraocular muscles, and helps monitor progression of disease
- MRI: alternative option to CT that can show similar findings to CT and, additionally, compression of the optic nerve
- This is a self-limiting disease, but intervention may be necessary because of severe symptoms or risk of complications.
- Goals of therapy include treatment of hyperthyroidism, smoking cessation, eye protection, and decreasing inflammation.
- Radioiodine therapy may initially worsen the appearance and symptoms of the disease, while surgery and thioamides do not affect the disease.
- If radioiodine therapy is used, steroids are recommended before and after treatment.
- Mild disease
Moderate to severe inflammation, nonresponders, or threatened/manifested vision loss: high-dose IV steroids
- If response is good: consider orbital radiation
- If no response after 48–72 hours → surgical decompression while on steroids
|Orbital cellulitis||Preseptal cellulitis|
|Epidemiology|| || |
|Clinical features|| |
|Complications||Although preseptal cellulitis can cause severe complications, these are rare, which is why the condition is rarely life-threatening.|
- Definition: malignant mesenchymal tumor of primitive skeletal muscle cells (rhabdomyoblasts) that have failed to fully differentiate
- Clinical features
- Open or core needle biopsy for light microscopy to look for rhabdomyoblasts (confirm the presence of rhabdomyosarcoma)
- Surgery (complete excision) if a functional and cosmetic result is possible
- Combination of radiation and chemotherapy following a diagnostic biopsy if complete excision is not feasible
- Prognosis: more favorable for localized tumors of the orbit , and less favorable for metastatic disease