Cavernous Sinus Flashcards
Cavernous sinus fistula
Result of abnormal communication between the AV systems. High pressure blood demo the carotid artery builds up with inthe cavernous sinus, preventing the return of venous blood from the globe of the eye; this reuslts in the classic unique triad of chemosis, pulsatile proptosis, and ocular bruit. Can be caused by trauma. Can be assoacited with high IOP, headaches, EOM trstrictions. Opthalmoplegia (CN 6 palsy) occurs in 50% of CFF
Most common cause if unilateral or bialteral proptosis in young or middle aged patients
TED
What is TED
AI disease characterized by TSH receptors autoABs directed against the EOMs and soft tissue within the orbit. Similar to patients with CFF, may have EOM restrictions. Fibrosis of the MR can resutls in an abduction deficits, mimicking a 6th nerve palsy
- unlike CFF, proptosis secondary to TED is not pulsatile and does not classically have a rapid onset
- if conj chemosis is present in TED, it is typically mild and no assocaited with an increase in IOP in the invovled eye
- patients with EOM restrictions secondary to TED will habe a positive forced duction test, in contrast to ophthalmoplegia resulting from CFF
Thyroid function and TED
30-70% of patients with TED have abnormal thyroid function, most commonly hyperthyroidism; patients may reports a Hx of systemic symptoms including heart palpitations, weight loss, heat intolerance, and/or hair loss
Orbital pseudotumor
Idiopathic inflammation of the soft tissues and muscles in the orbit. Characterized by a sudden onset, unilateral, painful proptosis in young to middle aged patients. It may also be associated with conjunctival chemosis and hyperemia, eyelid edema and hyperemia, EOM restrictions, decreased corneal sensation (V1), and an increased IOP on the invovled side. In general, patietns have decreased VA in the affected eye due to compression of the ONH
Chemosis
Typically bilateral and associated with allergic symptoms. If a patient presetns with unirlateral chemosis WITHOUT allergic symptoms, consider idiopathic orbital pseudotumor, esp in patietns 20-50yo
Orbital cellulitis
Infection posterior to the orbital septum. Leading cause of exophthlamos in kids. The classical presentation includes unilateral proptosis, eyelea edema, pain, and/or restrictions on eye movements causing diplopia, fever, decreased vision due to ONH compression (an APD will be present), and conjunctival chemosis and hyperemia. Potential etiologies include sinus infections (ethmoid), orbital infections, dental infections, orbital trauma, or previous ocular surgeries
Anterior encephalocele
Rare neural tube defect resulting in malformation of the bones of the skull, leading to increased risk of cerebrum protrusion from the skull. The brain and tissue and meninges may protrude anteriorly or posteriorly within the skull. Anterior encephalocele is typically associated with a better prognosis because it is less leaky to contain brain tissue (compared to posterior). It may result in a pulsatile proptosis that worsens when newborns cry; there is no thrill or ocualr bruit
CFFs causes
Spontaneously (ruptured carotid artery aneurysm), from associated cavernous sinuspatholgoy, or from recent trauma. 77% of CFFs result from closed head trauma
Diagnosing CFF
MRI and angiography
-asymmetrically enlarged cavernous sinus or superior ophthalmic vein
What condition is assocaited with minocyline
Pseudotumor cerebri
Treatment for CFF
Balloon embolization for high flow CFFs
Low flow observed without treatment, unless vision or life threatening situations develop
Dx and Tx of TED
Evaluation includes a CT scan of the orbits and blood work for thyroid function (T3/T4/TSH)
- the orbital CT scan will show enlargement of the bodies of the EOMs, WITHOUT tendon involvement (orbital pseudotumor involves tendon)
- bc pts with TED most often have hyperthyroidism, T3 and T4 values are often elevated and TSH levels are low (due to negative feedback loop between the thyroid and the pituitary glands). An endocrinology consult is warranted in patietns with confirmed TED
TED complications
Exposure keratopathy
SLK
Optic neuropathy
Restrictive myopathy
Treatment of SLK and exposure Keratopathy from TED
ATs, Mucomyst, punctal occlsuon, taping lids at bedtime, and/or lateral tarsorrhaphy or canthorrhaphy
Tarsorrhaphy
Procedures in which the upper and lower eyelids (lateral) are sewn together in order to reduce the size of the palpebral aperture to limit exposure of the ocular surface.
Canthorrhaphy
Shortening of the palpebral fissure of the eyelids by suturing the canthus. Although a tarsorrhaphy is very simialr, it is not restricted to the medial or lateral canthi, as it may involve the middle portion of the eyelid
Treatment of optic neuropathy from TED
Immediate treatment with oral steroids (pre 100mg QD for 2-14 days) or radiotherapy (less common) in order to reduce inflammation of the EOMs and orbital soft tissue. Orbital decompression surgery may be indicated if oral steroid treatment is contraindicated or ineffective
Treatment of restrictive myopathy from TED
Confirmed with forced duction test
- inferior and medial most commonly affected
- treatment is orbital decompression, followed by strab surgery
Graves and smoking
Sig increased risk of ophthalmic complications in patients with Graves’ disease (2-9x greater risk). Patients should be encouraged to stop smoking. Also recall that 1% of patietns with TED have or will develop MG
Orbital pseudotumor Dx and Tx
Orbital CT scan indicated and will show enlargement of bodies and tendons of EOMs
Treated with systemic steroids (oral pred 60-100mg QD for 2-3 weeks, with slow taper) leading to significant improvement in the first 24-48 hours; if does not respond in the first 48 hours, consider alternative DX
What should always be RXed in combo with high dose steroids
H2 PPIs
Orbital cellulitis DX
ENT tissue diagnosis of the sinuses and rule out fungal phycomycosis. Immunocompromised patients or patients with DM with orbital cellulitis can develop mucor, an aggressive and potentially life threatening fungal infection
Treatment for orbital cellulitis
Immediate hospitalization for a 1 week treatment with IC ABX, commonly ceftriaxone and naficillin, after improving on IV ABX therapy, patients are started on a 10 day course of oral abx such as augmentin 250-500mg TID, Ceclor 250-500mg TID, or Bactrim 1 double strength tablet QD (allergic to PCN)
-topical abx ointments indicated for concurrent conjunctivitis or corneal exposure
Anterior encephalocele dx
Prenatal ultrasound, refer to neurosurgery for consultation and treatemnt
