Cavernous sinus thrombosis is a very rare, typically septic thrombosis of the cavernous sinus, usually caused by nasal furuncles or bacterial sinusitis. Symptoms and signs include pain, proptosis, ophthalmoplegia, vision loss, papilledema, and fever. Diagnosis is confirmed by CT or MRI. Treatment is with IV antibiotics. Complications are common, and prognosis is guarded.
Etiology of 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 sphenoidal or ethmoidal sinusitis (greater than 50%), nasal furuncles, and dental infections (1). Common pathogens are Staphylococcus aureus (70%), followed by Streptococcus species; anaerobes are more common when the underlying condition is a dental infection.
Thrombosis of the lateral sinus (related to mastoiditis) and thrombosis of the superior sagittal sinus (related to bacterial meningitis) occur but are rarer than cavernous sinus thrombosis.
Etiology reference
1. Caranfa JT, Yoon MK. Septic cavernous sinus thrombosis: A review. Surv Ophthalmol. 2021;66(6):1021-1030. doi: 10.1016/j.survophthal.2021.03.009
Pathophysiology of Cavernous Sinus Thrombosis
Cranial nerves III (oculomotor), IV (trochlear), and VI (abducens) and the ophthalmic and maxillary branches of cranial nerve V (trigeminal) 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.
Symptoms and Signs of Cavernous Sinus Thrombosis
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, which may be associated with Horner syndrome), proptosis, and eyelid edema develop and often become bilateral. Facial sensation may be diminished or absent due to trigeminal nerve involvement. 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.
Diagnosis of Cavernous Sinus Thrombosis
MRI or CT
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 (1), but CT is also helpful. Contrast-enhanced MR venogram (MRV) and CT venogram are more sensitive than either CT or MRI. Useful adjunct testing may include blood cultures and lumbar puncture (1).
Diagnosis reference
1. Saposnik G, Bushnell C, Coutinho JM, et al. Diagnosis and management of cerebral venous thrombosis: A scientific statement from the American Heart Association. Stroke. 2024;55(3):e77-e90. https://doi.org/10.1161/STR.0000000000000456
Treatment of Cavernous Sinus Thrombosis
IV high-dose antibiotics
Sometimes glucocorticoids
Sometimes anticoagulation
Typical initial antibiotics for patients with cavernous sinus thrombosis include nafcillin or oxacillin combined with a third-generation cephalosporin. In areas where methicillin-resistant Typical initial antibiotics for patients with cavernous sinus thrombosis include nafcillin or oxacillin combined with a third-generation cephalosporin. In areas where methicillin-resistantS. aureus is prevalent, vancomycin should be substituted for nafcillin or oxacillin. An antimicrobial for anaerobes (eg, metronidazole) should be added if an underlying dental infection is present (is prevalent, vancomycin should be substituted for nafcillin or oxacillin. An antimicrobial for anaerobes (eg, metronidazole) should be added if an underlying dental infection is present (1, 2).
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 glucocorticoids (eg, dexamethasone) for cranial nerve dysfunction. Unfractionated or low-molecular-weight heparin is recommended in patients without contraindications. These medications reduce morbidity and mortality (Secondary treatment for cavernous sinus thrombosis may include glucocorticoids (eg, dexamethasone) for cranial nerve dysfunction. Unfractionated or low-molecular-weight heparin is recommended in patients without contraindications. These medications reduce morbidity and mortality (2).
Treatment references
1. Saposnik G, Barinagarrementeria F, Brown RD Jr, et al; American Heart Association Stroke Council and the Council on Epidemiology and Prevention. Diagnosis and management of cerebral venous thrombosis: A statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2011;42(4):1158-1192. doi: 10.1161/STR.0b013e31820a8364
2. Saposnik G, Bushnell C, Coutinho JM, et al. Diagnosis and management of cerebral venous thrombosis: A scientific statement from the American Heart Association. Stroke. 2024;55(3):e77-e90. https://doi.org/10.1161/STR.0000000000000456
Prognosis for Cavernous Sinus Thrombosis
Mortality in the antibiotic era is approximately 10 to 15%. Approximately one-third of surviving patients develop serious sequelae (eg, ophthalmoplegia, blindness); stroke and pituitary insufficiency are also possible (1).
Prognosis reference
1. Halawa O, Gibbons A, Van Brummen A, Li E. Septic cavernous sinus thrombosis: Clinical characteristics, management, and outcomes. J Neuroophthalmol . 2025;45(1):50-54. doi: 10.1097/WNO.0000000000002146
Key Points
Cavernous sinus thrombosis is an extremely rare complication of infections such as sphenoidal or ethmoidal sinusitis, nasal furuncles, and dental infections.
Consider the diagnosis in patients at risk who have facial pain and fever, particularly with mental status changes, ophthalmoplegia (eg, with the 6th cranial nerve), Horner syndrome, proptosis, and/or eyelid edema.
Obtain immediate neuroimaging with MRI or CT (or contrast-enhanced MR venogram or CT venogram if immediately available).
Treat with antistaphylococcal antibiotic plus a third-generation cephalosporin, and, if dental infection is present, metronidazole; anticoagulation should be instituted if there is no contraindication.Treat with antistaphylococcal antibiotic plus a third-generation cephalosporin, and, if dental infection is present, metronidazole; anticoagulation should be instituted if there is no contraindication.
