Disease's of the Orbit Flashcards
What is the most common cause of axial proptosis both uni- and bilaterally in adults?
Thyroid eye disease
How does hyperthyroidism lead to the development of proptosis?
Hyperthyroidism is an autoimmune disease. There are two phases to the eye disease. Firstly the active inflammatory stage which causes read and painful eyes, Then there is the inactive fibrotic phase which involves the extraocular muscles and connective tissues.
What causes eyelid retraction in graves disease?
The overstimulation of the muller muscle, due to high levels of Thyroid hormones.
what is von Graefe sign?
The lid lag on downward gaze
What is Kocher sign?
A ‘staring’ appearance
What order are the EOM typically affected by the deposition of the glycosaminoglycans?
IR MR SR LP LR
What investigations should be done for suspected thyroid disease?
TFTs
Imaging - CT or MRI is indicated if orbital decompression is planned
Visual field testing
What management options are there for thyroid eye disease?
Smoking cessation Thyroid management Watchful waiting Lubricating orbit topical ciclosporin overnight lid taping IV methylprednisolone Orbital radiotherapy Surgery - post inflammatory phase. May require orbital decompression, strabismus surgery or eyelid surgery.
What are some complications of thyroid eye disease?
Dysthyroid optic neuropathy
Superior limbic keratoconjunctivitis
Exposure keratopathy
What is another orbital disease, which is similar to cellulitis but presents more gradually and is often seen in immunocompromised patients on in DKA?
Orbital mucormycosis
A fungal infection caused by mucoracea
What is a characteristic of orbital murcomycosis?
Necrotic black eschars over the nasal turbinates and palate.
What are the most common causative organisms of orbital cellulitis?
Strep Pneumoniae
Staph Aureus
Haemophilus influenzae
What investigation should you do for orbital cellulitis?
CT
What is the appropriate management for orbital cellulitis?
IV antibiotics - ceftriaxone + flucloxacillin
List some complications of orbital cellulitis?
Abscess
Cavernous sinus thrombosis
Brain abscess / meningitis
Neuropathy
What type of rare tumours present in childhood and form a blood-filled ‘chocolate’ cyst?
Lymphangioma
What are some characteristics of an anterior lymphangioma?
Bluish mass
Superonasally on the eyelid
Exacerbated by Valsalva manoeuvre
What are the two types of optic nerve tumours?
Glioma
Meningioma
What is the most common primary orbital malignancy in children?
Rhabdomyosarcoma
Give some characteristics of rhabdomyosarcoma’s of the orbit?
Typically affect children, mean age 8y/o.
Has the ability to differentiate into striated muscle from undifferentiated mesenchymal cells
Rapidly progressing unilateral proptosis
Diplopia may occur
What is a carotid-cavernous fistula?
This is the development of an arteriovenous connection between the cavernous sinus (venous) and the carotids (arterial)
Direct are often due to trauma while indirect can be due to hypertension and will occur spontaneously
What is the most common solid, extracranial tumour in children that forms from the neural crest of the sympathetic?
Neuroblastoma.
What are some features of a neuroblastoma?
Homer-Wright rosettes
Child with periorbital ecchymosis and uni/bilateral proptosis.
What condition can be associated with optic nerve gliomas?
Neurofibromatosis 1
