What are the signs of cavernous sinus thrombosis?

Cavernous Sinus Thrombosis: Clinical Signs and Presentation

Cavernous sinus thrombosis presents with a characteristic triad of fever, headache, and progressive ocular manifestations including periorbital edema, chemosis, proptosis, and ophthalmoplegia—with cranial nerve VI palsy (lateral rectus weakness) being the most common cranial nerve finding. 1, 2

Cardinal Clinical Features

Ocular Manifestations (Nearly Universal)

• Periorbital edema and chemosis develop in almost all recognized cases and are among the earliest signs 1, 2, 3
• Proptosis (bulging eye) occurs due to impaired venous drainage from the orbit 4
• Ophthalmoplegia with limitation of extraocular movements, particularly lateral gaze palsy from cranial nerve VI involvement (most commonly affected) 1, 2
• Ptosis (drooping eyelid) may be present 5
• Vision changes including diplopia are common presenting complaints 1, 5

Systemic Signs

• Fever is present in nearly all cases (approaching 100% in septic cavernous sinus thrombosis) 1, 2, 3
• Headache is prevalent but may not be as prominent as in other forms of cerebral venous thrombosis 1, 2

Cranial Nerve Involvement Pattern

• Cranial nerve VI (abducens) is affected first and most frequently, causing inability to abduct the eye laterally 1, 2
• Cranial nerves III, IV, and V may subsequently become involved as the thrombosis progresses 1
• The ophthalmic and maxillary divisions of cranial nerve V can cause facial pain and sensory changes 4

Critical Temporal Pattern

Bilateral involvement is a hallmark feature: The opposite eye frequently develops signs within 2 days following the onset of unilateral symptoms, distinguishing cavernous sinus thrombosis from other orbital conditions 2, 3. This rapid bilateral progression should raise immediate suspicion for this diagnosis.

Common Antecedent Conditions

The most common underlying etiology is infection of the middle third of the face (the "danger triangle"), particularly: 1, 2, 3

• Sphenoid or ethmoid sinusitis (most common paranasal source) 6, 4
• Facial skin infections several days prior to CST development 1
• Dental abscess or recent dental procedures 5, 4
• Less commonly: otitis media 2, 3

Important Clinical Pitfalls

Subacute Presentations Exist

While most cases present acutely, not all cavernous sinus thrombosis presents typically and acutely—subacute presentations with symptoms evolving over weeks to months can occur, making diagnosis challenging 5. Maintain high clinical suspicion when ocular symptoms follow facial infections or dental procedures, even if the timeline is prolonged.

Headache May Be Subtle

Unlike other forms of cerebral venous thrombosis where headache is the dominant symptom (90% of cases) 7, 8, headache in cavernous sinus thrombosis may not be prominent, potentially delaying recognition 2.

Laboratory Findings

• Elevated inflammatory markers are typically present 1
• Blood cultures are positive in up to 70% of cases, with Staphylococcus aureus being the most common pathogen, followed by streptococcal species 1, 4

Prognosis Context

Despite modern treatment, complete recovery occurs in less than 50% of patients, with mortality remaining around 30% and the majority experiencing neurological sequelae 2, 3, 4. This high morbidity and mortality underscores the critical importance of rapid recognition based on the clinical signs described above.