Halo Sign refers to a Double ring appearance on filter paper seen when a mixture of Blood & Cerebrospinal Fluid (CSF) is dropped onto absorbent paper.
🩺 Where is it Seen?
Seen in cases of Suspected CSF Leak.
Especially:
CSF Rhinorrhea
CSF Otorrhea
What are the other names of Halo sign seen in CSF Leaks?
🧪 How is the Test Performed?
A drop of suspected nasal discharge is placed onto Filter paper.
If CSF is mixed with blood:
Blood remains concentrated centrally
CSF spreads outward
creating a characteristic Double Ring Appearance.
Why does the double ring appareance occur in CSF Leaks?
🎯 Why is it Called Halo Sign?
The clear outer ring surrounds the central blood spot like a Halo around an object.
Hence the name Halo Sign.
Does Halo Sign Confirm CSF Leak?
❌ No, it is only suggestive.
What is the most common cause of CSF Leak?
What is the Gold Standard Test for Confirming CSF Leak?
What is the most Important Complication of Untreated CSF Leak?
Halo Sign (Ear)
📌 Type of Sign
👉 Radiological sign
Seen on CT Temporal Bone.
🔍 What is the Sign?
Halo Sign refers to a Radiolucent ring surrounding the cochlea giving a Double Ring Appearance on CT scan.
🩻 Where is it Seen?
Seen in Cochlear Otosclerosis.
🧠 Why Does it Occur?
In cochlear otosclerosis there is Demineralization of the otic capsule around the cochlea.
This produces a Hypodense zone surrounding the cochlea.
The resulting radiolucent ring creates the characteristic Halo Appearance.
🎯 Clinical Significance
Presence of Halo Sign indicates Inner ear involvement and suggests a Sensorineural component to the hearing loss.
🎯 Why is it Called Halo Sign?
The radiolucent ring surrounds the cochlea like a Halo creating a characteristic double-ring appearance.
What section of the CT scan of Temporal bone is the halo sign best seen in?
What is the most Common Bone Involved in Otosclerosis?
What is the most Common Site of Otosclerosis?
What are the audiological Findings seen in Otosclerosis in Pure Tone Audiogram & Impedance Audiometry?
What is the most Common Hearing Loss seen in Otosclerosis?
⭐ High Yield Rapid Revision Table
Feature
Halo Sign (Nose)
Halo Sign (Ear)
Type
Clinical sign
Radiological sign
Test
Filter paper test
CT Temporal Bone
Appearance
Double ring pattern
Radiolucent cochlear ring
Seen In
CSF Rhinorrhea / CSF Leak
Cochlear Otosclerosis
Mechanism
Different diffusion of CSF and blood
Demineralization of otic capsule
Significance
Suggests CSF leak
Indicates cochlear involvement
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