Signs in ASOM & Acute Mastoiditis | Cartwheel Sign, Lighthouse Sign, Ironed Out Mastoid & Reservoir Sign
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Signs in ASOM & Acute Mastoiditis
Several classical signs are associated with Acute Suppurative Otitis Media (ASOM) and Acute Mastoiditis.
In this post, we will discuss:
- Cartwheel Sign
- Lighthouse Sign
- Ironed Out Appearance of Mastoid
- Reservoir Sign
Cartwheel Sign
📌 Type of Sign
👉 Clinical Sign seen during Otoscopic examination.
🔍 What is the Sign?
Cartwheel Sign refers to a congested tympanic membrane with a leash of blood vessels along the handle of the malleus and at the periphery of the tympanic membrane.
Seen in Acute Suppurative Otitis Media.
📍 Stage of ASOM
👉 Stage of Pre suppuration
Why is the Cartwheel appearance seen in the stage of pre suppuration in ASOM?
What are the stages of ASOM?
🎡 Why is it Called Cartwheel Sign?
The radially oriented congested vessels resemble the spokes of a cartwheel, hence the name Cartwheel Sign.
Lighthouse Sign
📌 Type of Sign
👉 Clinical Sign seen during Otoscopy.
📌 Also Known As
👉 Pulsatile Otorrhea
🔍 What is the Sign?
Lighthouse Sign refers to pus coming out under pressure through a small pinhole perforation of the tympanic membrane, in synchrony with the arterial pulse.
Seen In
1- Acute Suppurative Otitis Media - In the transitory phase from the stage of suppuration to the stage of early resolution, when the tympanic membrane perforates
2- Acute Mastoiditis
🧠 Why Does it Occur?
- Pus collects in the middle ear and mastoid
- Pus comes out under pressure through the pinhole perforation
- Vascular pulsations within the middle ear make the discharge pulsatile
- The discharge reflects light intermittently as it comes out
🚨 Why is it Called Lighthouse Sign?
The tiny perforation emits pulsatile discharge intermittently, resembling a lighthouse beam flashing intermittently, hence the name Lighthouse Sign.
Ironed Out Appearance of Mastoid
📌 Type of Sign
👉 Clinical Sign seen during Examination of the mastoid.
🔍 What is the Sign?
Ironed Out Appearance refers to a smooth, shiny, flattened appearance of the skin over the mastoid region, with loss of the normal bony contour.
Seen in Acute Mastoiditis.
What does a normal mastoid feel on palpation?
🧠 Why Does it Occur?
Infection starts in the middle ear
→ Spreads to the mastoid air cells
→ Pus breaks through the mastoid cortex
→ Periosteitis and subperiosteal pus collection
→ Thickened periosteum
→ Overlying skin becomes stretched, shiny and swollen
👔 Why is it Called Ironed Out Appearance?
The mastoid appears flat, smooth and polished, like cloth that has been ironed, hence the name Ironed Out Appearance.
Reservoir Sign
📌 Type of Sign
👉 Clinical Sign seen during Otoscopy.
🔍 What is the Sign?
Reservoir Sign refers to immediate refilling of the external auditory canal with pus or discharge, as soon as it is suctioned and cleared.
Seen in Acute Mastoiditis.
🧠 Why Does it Occur?
- Pus accumulates in the mastoid and middle ear
- There is continuous pus production
- Suctioning cannot keep up with the rate of pus production
- Pus continuously drains into the external auditory canal
🪣 Why is it Called Reservoir Sign?
The mastoid and middle ear act like a reservoir of pus, which keeps spilling into the external auditory canal and refilling it, hence the name Reservoir Sign.
What are some signs seen in Acute Mastoiditis?
⭐ High Yield Rapid Revision Table
| Sign | Type | Finding | Seen In |
|---|---|---|---|
| Cartwheel Sign | Clinical | Congested tympanic membrane with radiating blood vessels | ASOM (Stage of Pre suppuration) |
| Lighthouse Sign | Clinical | Pulsatile pus through a pinhole perforation | ASOM (Suppuration → Early resolution), Acute Mastoiditis |
| Ironed Out Mastoid | Clinical | Smooth, shiny, flattened skin over the mastoid | Acute Mastoiditis |
| Reservoir Sign | Clinical | External auditory canal refills with pus immediately after suctioning | Acute Mastoiditis |
🧠 Viva Pearls
- Cartwheel Sign is seen in the stage of pre suppuration of ASOM.
- In the Cartwheel Sign, congested vessels radiate from the handle of the malleus like the spokes of a cartwheel.
- Lighthouse Sign is also known as pulsatile otorrhea.
- Lighthouse Sign is seen in ASOM and acute mastoiditis.
- In ASOM, the Lighthouse Sign is seen in the transitory phase from suppuration to early resolution.
- Ironed Out Appearance of the mastoid is due to subperiosteal pus collection and periostitis.
- A normal mastoid feels pitted on palpation.
- Reservoir Sign is immediate refilling of the external auditory canal with pus after suctioning.
- Reservoir Sign is due to continuous pus production in the mastoid and middle ear.
- Obliteration of the retroauricular sulcus and sagging of the posterosuperior meatal wall are also seen in acute mastoiditis.
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