Otology: Lateral Sinus Thrombophlebitis (Sigmoid Sinus Thrombosis)
High-Yield Revision for NEET PG
Lateral sinus thrombophlebitis is a severe intracranial complication of otitis media characterized by inflammation and thrombus formation within the sigmoid (lateral) sinus.
1. Classic Clinical Signs
- “Picket-Fence” Fever: Classic hectic fever spikes with rigors, indicating periodic septic emboli (though now less common due to early antibiotics).
- Griesinger’s Sign: Edema and tenderness over the posterior part of the mastoid due to thrombosis of the mastoid emissary vein.
- Tobey-Ayer Test: A diagnostic test where manual compression of the internal jugular vein on the healthy side produces a rapid, significant rise in CSF pressure, whereas compression on the affected (thrombosed) side shows no effect.
- Crowe-Beck Sign: Compression of the healthy jugular vein results in engorgement of retinal veins, whereas compression on the affected side does not.
2. Diagnostics & Imaging
| Method | Finding |
|---|---|
| CT Scan (Contrast) | “Delta Sign”: A triangular area of peripheral enhancement with a central low-density filling defect. |
| MRI/MRV | More sensitive; demonstrates absence of venous flow and signal intensity changes within the thrombus. |
3. NEET PG High-Yield Pearls
- Management: Requires aggressive IV antibiotics and surgical intervention (typically Canal Wall Down Mastoidectomy with removal of the clot and perisinus infection).
- Pathophysiology: Infection spreads through bone erosion (e.g., cholesteatoma) or thrombophlebitis of the small venules around the dura.
- Complications: Can propagate to the jugular bulb, causing tenderness along the sternocleidomastoid muscle (Jugular vein thrombosis), or lead to intracranial hypertension (papilledema).