Cavernous Sinus Thrombosis
The cavernous sinuses are trabeculated sinuses located at the base of the skull that drain venous blood from facial veins. Cavernous sinus thrombosis is an extremely rare complication of common facial infections, most notably nasal furuncles (50%), sphenoidal or ethmoidal sinusitis (30%), and dental infections (10%). Most common pathogens are Staphylococcus aureus (70%), followed by Streptococcus species; anaerobes are more common when the underlying condition is dental or sinus infection.
The 3rd, 4th, and 6th cranial nerves and the ophthalmic and maxillary branches of the 5th cranial nerve are adjacent to the cavernous sinus and are commonly affected in cavernous sinus thrombosis. Complications of cavernous sinus thrombosis include meningoencephalitis, brain abscess, stroke, blindness, and pituitary insufficiency.
Initial symptoms of cavernous sinus thrombosis are progressively severe headache or facial pain, usually unilateral and localized to retro-orbital and frontal regions. High fever is common. Later, ophthalmoplegia (typically the 6th cranial nerve in the initial stage), proptosis, and eyelid edema develop and often become bilateral. Facial sensation may be diminished or absent. Decreased level of consciousness, confusion, seizures, and focal neurologic deficits are signs of central nervous system (CNS) spread. Patients with cavernous sinus thrombosis may also have anisocoria or mydriasis (3rd cranial nerve dysfunction), papilledema, and vision loss.
Cavernous sinus thrombosis is often misdiagnosed because it is rare. It should be considered in patients who have signs consistent with orbital cellulitis. Features that distinguish cavernous sinus thrombosis from orbital cellulitis include cranial nerve dysfunction, bilateral eye involvement, and mental status changes.
Diagnosis is based on neuroimaging. MRI is the better study, but CT is also helpful. Useful adjunct testing may include blood cultures and lumbar puncture.
Mortality is 30% in all patients with cavernous sinus thrombosis and 50% in those with underlying sphenoid sinusitis. An additional 30% develop serious sequelae (eg, ophthalmoplegia, blindness, disability due to stroke, pituitary insufficiency), which may be permanent.
Initial antibiotics for patients with cavernous sinus thrombosis include nafcillin or oxacillin 1 to 2 g every 4 to 6 hours combined with a 3rd-generation cephalosporin (eg, ceftriaxone 1 g every 12 hours). In areas where methicillin-resistant S. aureus is prevalent, vancomycin 1 g IV every 12 hours should be substituted for nafcillin or oxacillin. A drug for anaerobes (eg, metronidazole 500 mg every 8 hours) should be added if an underlying sinusitis or dental infection is present.
In cases with underlying sphenoid sinusitis, surgical sinus drainage is indicated, especially if there is no clinical response to antibiotics within 24 hours.
Secondary treatment for cavernous sinus thrombosis may include corticosteroids (eg, dexamethasone 10 mg IV or orally every 6 hours) for cranial nerve dysfunction; anticoagulation is controversial because most patients respond to antibiotics, and adverse effects may exceed benefits.