Pneumatic Otoscopy

PNEUMATIC OTOSCOPY Definition: Pneumatic otoscopy is a diagnostic technique used to assess the landmarks, mobility, transparency, color and vascularity, and position of the tympanic membrane as well as the presence of pathologic middle ear abnormalities. The pneumatic otoscope: This photograph shows two views of a pneumatic otoscope head which are separated by a size oo metal ear curette. The otoscope head attaches to handle containing a power source. The otoscope head consists of a plastic ear speculum, a unit which contains a light bulb and fiberoptic illumination system, a retractable magnification lens, and a smaller operating lens. A rubber bulb is attached to the head of the otoscope with a piece of plastic tubing.

The otoscope head is a closed air system except for the opening of the ear speculum which is inserted in the ear canal. In order to assess tympanic membrane mobility, the tip of the ear speculum must make an adequate seal with the ear canal. Failure to make an adequate seal is the most common reason that clinicians have difficulty in accurately determining membrane mobility. Attaching a small piece of rubber tubing snugly around the ear speculum as shown in the picture will help to achieve a good seal while minimizing the child's discomfort. Visualization of tympanic membrane landmarks: The first step in becoming a skilled otoscopist is learning to recognize the tympanic membrane landmarks. This schematic diagram of a left tympanic membrane shows how the membrane can be divided into four quadrants by a line drawn through the long process of the malleus and its perpendicular line through the center of the umbo.

Views

External View

Internal View

The photographs show two views of the middle ear; one external view as seen with an otoscope and another internal view as seen with an endoscope passed through the Eustachian tube. The landmarks include the light reflex (1), the umbo of the malleus (2), long process of the malleus (3), lateral process of the malleus (4), and the incus (5). The malleus and incus as well as the stapes (8) are ossicles or small bones which play an important role in conducting sound across the middle ear space. A branch of the facial nerve called the chorda tympani (9) runs adjacent to the incus. The tympanic membrane above the short process of the malleus is called the pars flacida (6) while the remainder of the membrane is called the pars tensa (7).

Light Reflex The cone light reflex is often the easiest landmark to visualize. Locating it orients you to the other tympanic membrane landmarks. Note that the cone light reflex appears as a cone in the anterior inferior quadrant of the tympanic membrane. The broad base of the light reflex points anteriorly while the narrower section of the cone points to the end of the malleus named the umbo.

External View

Schematic View

After locating the cone light reflex, follow the narrow end of the cone light reflex to the umbo and then visualize the malleus. Follow the long process of the malleus superiorly where it forms the short or lateral process in the anterior superior quadrant.

Incus After viewing the lateral process of the malleus, look at the area in the posterior superior quadrant just posterior to the short process and malleus. When the membrane is translucent you often can see a small whitish bone called the incus.

It is important to get a good view of this area because this is the location where most retraction pockets and cholesteatomas develop. Next look at the entire membrane to identify tympanosclerosis or a perforation.

Color

Tympanic Membrane Appearance: Transparency, Color and Vascularity Look to see if light diffuses through the membrane so that the bony landmarks are clearly visible. The membrane is transparent when light passes through the membrane as shown in the image above. When some light passes through the membrane is translucent. The membrane is opaque when light does not pass through the membrane so that the bony landmarks can not be clearly seen. (as shown below)

The color of the tympanic membrane can be considered red, amber, or yellow. The membrane may also appear colorless in the absence of inflammation. The tympanic membrane shown above, is both a yellow and red color. Increased vascularity present on the tympanic membrane can produce injection. This is often most prominent on the malleus. (as shown below) Increased vascularity may result when a child cries, or from irritation associated with removing cerumen from the ear canal. It is a common reason for overdiagnosing Acute Otitis Media.

Bulging Tympanic Membrane Position: The tympanic membrane can appear to be bulging outward, retracted, or in its normal location. Bulging: When the middle ear space contains a large amount of fluid, the membrane is forced outward. Note that the membrane seems to bulge around the umbo creating a donut like appearance. The bulging often impairs the visibility of the bony landmarks.

Retraction: The key to recognizing retraction of the tympanic membrane is the position of the lateral process of the malleus and foreshortening of the long process of the malleus. Note in the left diagram that the lateral process is very prominent and that the long process appears rotated upward. The lateral process is usually oriented in the direction that corresponds to about 8 o'clock in a circular watch dial. When negative pressure in the middle ear space retracts the tympanic membrane the lateral process may be pulled superiorly so that the orientation of the lateral process becomes shifted towards 9 or 10 o'clock. When the membrane is more severely retracted the short process becomes very prominent. Another sign of negative pressure in the middle ear space and retraction of the membrane is the loss of space between the lateral process and the pars flacida (see green arrow on right diagram). The lateral process appears to almost touch the pars tensa.

Retraction with Negative Middle Ear Pressure Normal Middle Ear Pressure

Tympanic Membrane Mobility: The best way to determine the presence of middle ear fluid is by assessing membrane mobility. Squeezing the rubber bulb introduces air into the pneumatic otoscope system and creates a positive pressure on the outside surface of the tympanic membrane. The positive pressure normally displaces the tympanic membrane inward. When the rubber bulb is released air is sucked out of the ear canal creating a negative pressure outside the tympanic membrane. This negative pressure displaces the tympanic membrane outward. Thus alternating squeezing and releasing of the rubber bulb will cause the tympanic membrane to move briskly if no fluid is present. Normal Mobility The diagram and video shown below demonstrate brisk movement equally in both directions associated with normal mobility.

Decreased Mobility When fluid is present in the middle ear space the mobility will be diminished or absent. It is important to remember that excessive pressure produced by the rubber bulb may result in some mobility of the tympanic membrane even in the presence of middle ear fluid. The diagram and video shown below demonstrate this concept. Increased Mobility with Negative Pressure

When the tympanic membrane is retracted with negative middle ear pressure, the movement is greater when the bulb is released than when it is compressed. Therefore mobility is increased with negative pressure compared to positive pressure. The diagram and video shown below demonstrate this concept.

Middle Ear Conditions: Pneumatic otoscopy is useful in identifying pathologic conditions such as acute otitis media, middle ear effusions (residual and persistent), eustachian tube dysfunction with negative middle ear pressure, tympanosclerosis, tympanic membrane perforations, retraction pockets, adhesive otitis media, and cholesteatomas. Acute Otitis Media: Acute otitis media is characterized by inflammation of the middle ear space which presents with the rapid onset of symptoms such as otalgia, fever, irritability, anorexia, or vomiting. Acute otitis media is often associated with an upper respiratory infection or cold. Findings of middle ear inflammation include middle ear fluid causing decreased tympanic membrane mobility and bulging with impaired visibility of bony landmarks, a red or reddish yellow color, exudate on the membrane, or bullae.

Otitis media with effusion Otitis media with effusion is characterized by an asymptomatic middle ear effusion, that may be associated with a "plugged ear" feeling. The membrane often appears translucent but may be opaque when children have experienced frequent episodes of acute otitis

media. There is diminished membrane mobility which is often associated with a retracted position.

As the fluid clears air fluid levels or bubbles may be seen through the membrane as seen in the images below. Fluid present from 3 to 16 weeks following the diagnosis of acute otitis media without otoscopic signs of inflammation is a residual effusion. After 16 weeks the fluid can be classified as a persistent effusion. Tympanosclerosis Tympanosclerosis is a form of membrane thickening produced by hyalization. It results from chronic inflammation or trauma; often in association with the insertion of ventilating tubes.

Perforations Tympanic membrane perforations can occur in the pars tensa or pars flacida.

Most perforations produced by acute otitis media heal within a few days when the tympanic membrane is otherwise normal. The persistence of drainage, called otorrhea, for 6 weeks or longer is classified as chronic suppurative otitis media.

Tympanic Membrane Atalectasis, Retraction Pockets and Adhesive Otitis Media Retraction pockets occur when chronic inflammation and negative middle ear pressure produce atrophy and atelectasis of the tympanic membrane. This produces a defect or pocket which is usually located in the posterior superior area of the pars tensa or in the pars flacida. The tympanic membrane may adhere to the medial wall of the middle ear. Atrophy of the tympanic membrane can occur without a retraction pocket because of chronic inflammation with or without prior perforations. When adhesions develop between the retraction pocket and ossicles, insertion of a ventilating tube fails to restore normal ventilation and the pocket will persist (see diagram above). This condition is called

adhesive otitis media, which may lead to erosion of the ossicles and ossicular discontinuity, or the development of a cholesteatoma. Cholesteatoma

A cholesteatoma is a greasy-looking mass or accumulation of debris that is seen in a retraction pocket or perforation. It often presents as chronic otorrhea unresponsive to antibiotic therapy. The diagram below shows how a retraction pocket can enlarge and accumulate debris to form an acquired cholesteatoma. Cholesteatomas also may be congenital.