Several classical signs are associated with lateral (sigmoid) sinus thrombosis. In this post, we will discuss:
Delta Sign
Griesinger Sign
Picket Fence Fever
Delta Sign
📌 Type of Sign
👉 Radiological Sign seen on:
Contrast enhanced CT (CECT)
MRI
📌 Also Known As
👉 Empty Triangle Sign
🔍 What is the Sign?
Delta Sign refers to a triangular filling defect within the dural venous sinus, surrounded by contrast enhancement.
It is seen as:
Central low density
Triangular rim enhancement around it
Seen in Lateral Sinus Thrombosis.
Which section of CT Scan is it seen in?
What is the reason behind Delta sign?
🔺 Why is it Called Delta Sign?
The appearance resembles a triangle (delta), hence the name Delta Sign.
As it looks like an empty triangle, it is also called the Empty Triangle Sign.
What is the most common cause of lateral sinus thrombosis?
Griesinger Sign
📌 Type of Sign
👉 Clinical Sign seen during Mastoid examination.
🔍 What is the Sign?
Griesinger Sign refers to edema of the post-auricular soft tissues overlying the mastoid process, due to thrombosis of the mastoid emissary vein.
Tenderness is also present over this area.
Seen in Lateral Sinus Thrombosis.
What is the pathogenesis involved in Griesinger Sign?
👨⚕️ Eponym
Named after Griesinger, who described mastoid region edema due to mastoid emissary vein thrombosis in sigmoid sinus thrombosis.
Picket Fence Fever
📌 Type of Sign
👉 Clinical Sign
🔍 What is the Sign?
Picket Fence Fever refers to a characteristic fever pattern with spikes of high temperature separated by normal or near-normal readings.
Seen in Lateral Sinus Thrombosis.
🧠 Why Does it Occur?
Fever spikes are due to Septicemia.
Septicemia coincides with release of septic emboli into the bloodstream
Each release of septic emboli → A spike in temperature
Temperature then returns to normal
What are the Features of Picket Fence Fever?
🪵 Why is it Called Picket Fence Fever?
The temperature chart, with repeated high spikes separated by normal readings, resembles a picket fence, hence the name Picket Fence Fever.
⚠️ Important Viva Pearl
Picket Fence Fever is ❌ Not seen in every case of lateral sinus thrombosis
Patients who have started receiving antibiotics may not show this fever pattern.
⭐ High Yield Rapid Revision Table
Sign
Type
Finding
Cause
Delta Sign
Radiological
Triangular filling defect with rim enhancement on CECT / MRI
Thrombus in dural venous sinus
Griesinger Sign
Clinical
Edema of post-auricular soft tissue over the mastoid
Thrombosis of mastoid emissary vein
Picket Fence Fever
Clinical
High temperature spikes separated by normal readings
Septicemia with release of septic emboli
🧠 Viva Pearls
Delta Sign, Griesinger Sign and Picket Fence Fever are seen in lateral sinus thrombosis.
Delta Sign is a radiological sign seen on contrast enhanced CT or MRI.
Delta Sign is also known as Empty Triangle Sign.
In the Delta Sign, the central non-enhancing area is the thrombus and the rim enhancement is the normal dura.
Griesinger Sign is edema over the mastoid due to thrombosis of the mastoid emissary vein.
Griesinger Sign is elicited during mastoid examination.
Picket Fence Fever is caused by septicemia with repeated release of septic emboli.
Picket Fence Fever is accompanied by chills, rigors and profuse sweating.
Picket Fence Fever may be absent in patients already on antibiotics.
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