Aarti Sarwal, MD
DESCRIPTION 
- Cavernous sinus thrombosis (CST) is a rare disorder characterized by clot formation in the cavernous sinuses.
- Because of its complex neurovascular anatomic relationship, CST is the most important of any intracranial septic thrombosis.
EPIDEMIOLOGY
Incidence
- CST is generally a fulminant process with high rates of morbidity and mortality with only a few hundred case reports in the medical literature.
- Fortunately, the incidence has markedly decreased with the advent of effective antimicrobial agents.
- There is no known age, sex, or race predilection.
RISK FACTORS
- Infection: Middle third of the face, paranasal sinuses, pharynx, maxilla, middle ear, or mastoid process in otherwise healthy individual
- Trauma: Otolaryngologic surgery or trauma
- Hypercoagulable states: Malignancy, pregnancy, oral contraceptive use
- Diabetes mellitus
- Chronic sinusitis
Pregnancy Considerations
Pregnancy is a risk factor for the aseptic form of CST.
GENERAL PREVENTION
Furuncles or abscesses (pimples) in the central portion of the face should not be manipulated without prior antibiotic coverage.
PATHOPHYSIOLOGY
- The cavernous sinuses are paired, interconnected, trabeculated cavities located on either side of the sella turcica, superior to the sphenoid sinus and posterior to the optic chiasm.
- They receive venous drainage from face, orbits, sinuses, and brain through valveless veins.
- The internal carotid artery and sixth cranial nerve pass through the sinuses, whereas the third, fourth, ophthalmic, and maxillary branches of the fifth cranial nerve lie within the lateral wall of the sinuses.
ETIOLOGY
- Any infection in structures with venous drainage to the cavernous sinuses may propagate through valveless veins. Once the organisms are caught in the trabeculations of the sinuses, inflammation and secretion of coagulase may lead to clot formation and thrombosis.
- In the rare chronic form, slow thrombosis of the sinuses allows time for formation of venous collaterals.
- Coagulase-positive Staphylococcus aureus accounts for most infections. Streptococcus pneumonie, Gram-negative bacilli, Rhizopus, Aspergillus, and Mucor can also be seen.
COMMONLY ASSOCIATED CONDITIONS
- Infection of the central face or paranasal sinuses, bacteremia or infections of the ear or maxillary teeth.
- Surgical or blunt trauma or hypercoagulable state leads to thrombosis of the cavernous sinus and often to bacterial superinfection.
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PHYSICAL EXAM
- Eye swelling that begins as a unilateral process and spreads to the other eye within 24–48 hours is pathognomonic for CST.
- Orbital swelling with cranial nerve involvement should raise suspicion of CST.
- Signs and symptoms of the primary infection, venous congestion and sepsis:
- Fever and headache
- Ptosis and pupillary dilation
- Chemosis of bulbar conjunctiva
- External or internal ophthalmoplegia
- Proptosis and periorbital edema
- Decreased visual acuity
- Meningeal signs
- Systemic signs indicative of sepsis including chills, fever, shock, delirium, and coma
DIAGNOSTIC TESTS AND INTERPRETATION
Lab
Initial Lab Tests
- CST is primarily a clinical diagnosis.
- Polymorphonuclear leukocytosis on CBC and blood cultures can help confirms an infectious etiology.
- CSF is consistent with either parameningeal inflammation or frank meningitis.
Imaging
Initial Approach
Contrast-enhanced CT or MRI of the head is the most sensitive and specific imaging studies to confirm the diagnosis and differentiate its CST from alternatives like orbital cellulitis.
Follow-Up & Special Considerations
Angiography and venography are considered when carotid-cavernous fistula or intracavernous aneurysm is suspected.
Diagnostic Procedures/Other
- Lumbar puncture: CSF is typically inflammatory but may not grow organisms
- Funduscopic examination
DIFFERENTIAL DIAGNOSIS
- Contralateral spread of signs and symptoms within 48 hours is virtually pathognomonic for CST.
- Differential to be considered include:
- Orbital or periorbital cellulitis
- Epidural or subdural infection
- Sinusitis
- Trauma at orbital apex or superior orbital fissure
- Orbit or optic nerve tumor
- Rhinocerebral mucormycosis
- Intracavernous carotid artery aneurysm
- Carotid-cavernous fistula
- Intraorbital pseudotumor or Tolosa–Hunt syndrome
- Exophthalmic goiter
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MEDICATION
First Line
- Antibiotics
- Early and aggressive high-dose, broad-spectrum antibiotics
- Coverage should include penicillinase producing Gram-positive, Gram-negative, and anaerobic organisms
- Dosed for CNS penetration
- Antifungals should be added in case patient has diabetes, neutropenia, or is otherwise immunosuppressed
- A regimen including intravenous oxacillin or nafcillin 2 g every 4 hours plus a third-generation antipseudomonal cephalosporin such as intravenous ceftazidime 2 g every 8 hours or IV imipenem 2 g every 6 hours should cover Gram-positive and Gram-negative organisms.
- IV metronidazole 500 mg every 6 hours should be added for anaerobic coverage
- If MRSA is suspected Vancomycin 1 g IV q12 or Linezolid may be added to the coverage
- IV antibiotics are recommended for a minimum of 3–4 weeks or at least 2 weeks beyond clinical resolution as the infection may be sequestered within the thrombus.
Second Line
- Anticoagulation
- Some studies have shown prevention of propagation and septic embolization (2)[C].
- Anticoagulation with heparin should be considered unless contraindications like presence of intracerebral hemorrhage or other bleeding diathesis exist.
- The duration for anticoagulation is controversial and may be considered for 3 and 9 months depending on the severity of symptoms and the clinical course.
- Corticosteroids may help to reduce inflammation and edema and may be instituted after antibiotic coverage.
- Pituitary insufficiency may develop necessitating steroid treatment.
ADDITIONAL TREATMENT
General Measures
- Eradicating the infection, halting progression of thrombosis, and reducing inflammation
- Rapid diagnosis and initiation of treatment are essential
Issues for Referral
- Infectious disease consultations for antibiotic choice
- Necessary surgical consultations should be sought
COMPLEMENTARY AND ALTERNATIVE THERAPIES
- Symptomatic treatment
- Pain control
SURGERY/OTHER PROCEDURES
Locally administered thrombolytics may be considered for severe refractory cases on experimental basis.
IN-PATIENT CONSIDERATIONS
Admission Criteria
Patients with diagnosed or suspected CST should be admitted to an intensive care unit.
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FOLLOW-UP RECOMMENDATIONS
Follow clinical course rather than normalization of imaging studies.
Patient Monitoring
Relapses and intracranial abscess have been reported weeks to months later due to sequestration of bacteria within thrombus. Thus, patients should be followed for several months after antibiotics are stopped.
PROGNOSIS
In the absence of treatment, meningitis, intracranial spread, septic shock, and death follow. Mortality rate is as high as 30%; the majority of survivors suffer permanent sequelae including blindness, visual impairment, diplopia, pituitary insufficiency, hemiparesis, seizure disorder, or vascular steal syndrome.
COMPLICATIONS
Complications and sequelae include
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ICD9
325 Phlebitis and thrombophlebitis of intracranial venous sinuses
Eye swelling that begins as a unilateral process and spreads to the other eye within 24–48 hours is pathognomonic for CST.