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COMMON CAUSES OF PROPTOSIS. What is proptosis ?. Abnormal protrusion of the eyeball. Exophthalmos : same as above but usually used in relation to endocrinopathies such as thyroid related proptosis . Pathophysiology.
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What is proptosis? • Abnormal protrusion of the eyeball. • Exophthalmos : same as above but usually used in relation to endocrinopathies such as thyroid related proptosis.
Pathophysiology • The basic pathophysiology irrespective of the aetiology is an increase in volume of the orbital content within the fixed bony orbital confines. • The orbit is widest anteriorly and not enclosed so the contents are displaced anteriorly resulting in proptosis.
Anatomy of the Orbit • A Pear shaped cavity with the optic canal as the stalk. • Has 4 parts: • Roof: • Formed by the lesser wing of sphenoid and frontal bones. Subjacent to the anterior cranial fossa and frontal sinus. • Any defect may lead to a pulsatileproptosis.
Lateral wall • Formed by greater wing of sphenoid and zygomatic bones. • Protects only the posterior half of the globe. • Anterior half is vulnerable to lateral trauma. • Floor: • Consists of zygomatic, maxillary and palatine bones. • Forms the roof of the maxillary sinus.
Contd.. • Maxillary carcinoma may invade the orbit displacing the globe upwards. • The posterior medial portion is weak predisposing it to blow out fractures. • Medial Wall: • Consists of 4 bones: maxillary, lacrimal, ethmoid, and sphenoid. • Has very thin lamina papyracea covering the medial wall and perforated by foramina for nerves and blood vessels. Therefore predisposed to orbital cellulitis secondary to ethmoidal sinusitis.
Importance of proptosis • Visual Threatening: exposure keratopathy, compressive optic neuropathy. • Life Threatening: malignant tumors. • Cosmetic implications
Causes of Proptosis • Primary orbital pathology. • Secondary to systemic diseases.
Contd... • Vascular: Orbital Varices, carotid cavernous fistula. • Inflammatory: Thyroid orbitopathy • Trauma: orbital haemorrhage, fractures • Aneurysm(CYSTIC LESIONS): dermoid cyst, encephlocele, mucocele. • Miscellaneous: Leukaemia, lymphoma, rhabdomyosarcoma, metastatic Ca. • Infection: Orbital Cellulitis • Neoplasm: Lacrimalpleomorphic adenoma optic nerve glioma, optic nerve sheath meningioma.
Clinical features • Symptoms depends on the cause: • Pain in inflammatory causes • Rapidly progressing protrusion in acute causes. • Poor vision from corneal lesions or optic nerve compression. • Restricted globe movement from extraocular muscle contraction as in thyroid eye disease.
Clinical Evaluation • Ocular: • Visual Acuity • Colour vision • Pupillary reflex • Extent of globe displacement using an exophthalmometer. • Globe retropulsion • Eyelid position
Examination contd... • Pulsation or thrill • Bruit on auscultation. • Cranial nerves. • Regional lymph nodes • Nasal • Thyroid • Breast • Prostate
Investigation • Radiological: • Plain x-ray: Caldwell view detects orbital lesion. Waters view, detects orbital floor fractures. • CT-scan: useful in locating and detecting SOL, in detecting FB, blood, emphysema.depicts bony structure. Doesn’t differentate radiological isodense tissue masses. • MRI: Can image orbital apex lesions and intracranial extensions. Not good with bony lesions
Haematological • WBC: total and differentials • Blood culture • Microbiology • Lumbar puncture for mcs • Conjunctival swab for mcs • Fine needle aspiration biopsy
Treatment • Depends on the cause: • Medical: • Antibiotics : topical and systemic for infective causes. • Chemotherapy for malignancies. • Surgical: • Excision • Interventional radiology with intravascular balloons introduced via a catheter to close the internal carotid artery fistula in CCF.