Cavernous sinus thrombosis

Dr Donna D'Souza et al.

Cavernous sinus thrombosis (CST) is a rare condition, most commonly infectious in nature, and the diagnosis on imaging is not always straightforward. It has high mortality and morbidity rates.

CST is rare with ~4.5 cases per 1,000,000 per year 5. It is the least common dural venous sinus thrombosis, accounting for <1.5% of cases 4.

A headache is the most common symptoms (85%. Focal neurological symptoms and/or seizures may also occur 5. Isolated CN III palsy is thought to be an early manifestation.

Orbital signs can include:

  • chemosis and peri-orbital swelling
  • exophthalamos
  • infection
    • most commonly results from contiguous spread of infection from the sinuses or middle third of the face, or less commonly dental abscess or orbital cellulitis
    • Staphylococcus aureus is the most common infectious microbe (~55% cases)
  • sinus compression, e.g. trauma, tumour
  • procoagulable conditions, e.g. Protein C/S deficiency, OCP use, malignancy
  • idiopathic (25%) 5

CST is a clinical diagnosis, however, MRI with contrast is the modality of choice to confirm its presence and to differentiate it from alternatives such as orbital cellulitis, which may have a similar clinical presentation.

  • non-contrast: high-density thrombus in affected cavernous sinus (seen in only 25%) 5
  • contrast-enhanced: distended cavernous sinus with a non fat density filling defect 4
  • T1 and T2 5
    • absent flow void
    • signal characteristics vary depending on the age of the thrombus but will be abnormal
  • contrast-enhancement or lack of is not a reliable indicator as organising thrombus can enhance
  • diagnosis can generally be made on venography

The mortality rate of CST is up to 30% with significant morbidity (e.g. blindness, cranial nerve palsy) in survivors not uncommon 6.

The dural venous sinuses and cerebral veins should also be carefully evaluated in cases of CST as up to 90% of patients will have multiple thromboses 5

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Article information

rID: 1065
Tag: cases
Synonyms or Alternate Spellings:
  • Thrombosis of the cavernous sinus

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