Diagnosis of Cavernous Sinus Thrombosis
Diagnosis of cavernous sinus thrombosis requires urgent investigation and typically begins with a thorough clinical assessment followed by imaging studies. Because CST is a medical emergency, speed and accuracy in diagnosis are crucial to initiate treatment as soon as possible.
1. Medical History and Physical Exam
Doctors will begin by taking a detailed history, including recent infections (such as sinusitis or facial boils), current symptoms, and underlying health conditions. The physical exam will focus on:
- Eye appearance and movement
- Facial swelling or tenderness
- Neurological function (e.g. alertness, eye reflexes, sensation)
- Vital signs to detect fever or signs of sepsis
The presence of periorbital swelling, proptosis, cranial nerve palsies, and fever strongly raises suspicion for cavernous sinus thrombosis.
2. Blood Tests | Diagnosis of Cavernous Sinus Thrombosis
Initial blood work includes:
- Full blood count (looking for elevated white blood cells)
- C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) for inflammation
- Blood cultures to identify the causative organism
These tests support the diagnosis and guide antibiotic therapy but are not diagnostic on their own.
3. Imaging
The most critical component of diagnosis is imaging of the brain and sinuses, typically using:
- MRI with MR venography (MRV): This is the preferred imaging technique and can visualise the thrombus in the cavernous sinus directly
- CT scan with contrast: Faster and more readily available in emergencies, though less sensitive than MRI
- CT venography may also be used where MRI is not possible
These scans help confirm the presence of a clot, assess for complications such as stroke or brain abscess, and detect the source of infection.
4. Lumbar Puncture | Diagnosis of Cavernous Sinus Thrombosis
If meningitis is suspected, a lumbar puncture may be performed to examine cerebrospinal fluid. This is only done if safe — after ruling out high intracranial pressure via imaging.
A timely and accurate diagnosis of cavernous sinus thrombosis allows for immediate treatment, which is vital for preventing life-altering complications. Delay in diagnosis significantly worsens the prognosis.
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