Otoscope

A Comprehensive Guideline To Otoscopes

Overview


An otoscope, or auriscope, is a medical device used by physicians to examine different compartments of the ear.
The use of otoscopes in family medicine is quite common, as physicians incorporate ear examination in the general checkup.
However, this device is most beneficial when a patient presents with symptoms, such as ear pain, tinnitus, or hearing impairment.

Otoscopes have a long history that helped millions of patients diagnose and treat complex conditions in their ear.
In this article, we will briefly discuss ear anatomy, and then move on to the basics of otoscopy.

Ear anatomy


The ear is divided into three compartments:

  • The external ear

This is the part that receives sound vibration and includes the outer ear (pinna) and the external auditory canal, which transmits sound vibrations to the eardrum (tympanic membrane).

  • The middle ear

It starts at the eardrum and includes the three major ear bones that respond to the vibrations transmitted from the tympanic membrane.

The middle ear is isolated from the external ear by the eardrum that prevents any fluid and/or air exchange between the two milieux.

However, this part has an outlet to the external milieu via the Eustachian tube, which connects the middle ear to the pharynx (throat). (1)


  • The inner ear

This is where the real magic happens!
In response to the bones’ movement in the middle ear, the fluid of the inner ear will change spatial positions. Consequently, these signals get transmitted to the brain via the auditory nerve.


History of otoscopes


Historians date the first otoscope to the mid-1300s when a French surgeon by the name of Guy de Chauliac

described a device that enables physicians to look inside the nasal and ear canals

This design was unchanged until after three centuries when Wilhelm Fabry

developed a new prototype that resembles the nasal speculum we use today.

In the 19th century, many physicians and surgeons started to modify the prototype to create a funnel-like structure that goes inside the ear.


Perhaps the most work was A. Hartmann’s version of the otoscope in Berlin (1881). In fact, some famous brands of otoscopes that we used today in practice (e.g. Welch Allyn) were initially designed by Hartmann.
Indications to use otoscopes
As mentioned earlier, an otoscope is used for a variety of reasons, including any symptom that affects the ear.
Without otoscopes, physicians would not be able to look inside the ear, which may delay the diagnosis and treatment of the underlying condition.
In this section, we will cover the most common chief complaints and conditions that require an otoscope-assisted ear examination.


Hearing impairment

There are three types of hearing impairment, depending on their etiology:

  • Conductive hearing impairment
  • Sensorineural hearing impairment
  • Mixed hearing loss

The main goal of otoscopy in this situation is to confirm or eliminate the diagnosis of conductive hearing loss.

As the name suggests, conductive hearing impairment is caused by a problem in either the outer or middle ear. (2)
The main causes of conductive hearing impairment include substantial accumulation of earwax, recurrent ear infections, ear tumors, abnormal growth of the bones inside the ear, and a ruptured eardrum.
When the physician takes a detailed look at the ear using an otoscope, he/she will be able to orient the diagnostic efforts toward the most probable cause of hearing loss.


Ear pain associated with fever

Otitis media is a common infection that affects the ears due to overgrowth of bacterial species, such as:

  • Streptococcus pneumoniae
  • Moraxella catarrhalis
  • Hemophilus influenzae
  • Pseudomonas aeruginosa

By using the otoscope, the doctor will look for signs of inflammation, pus, and swollen ear tissue. Add these findings to systemic signs, such as fever and chills, and the diagnosis of otitis media is almost certain.

These patients need a short course of antibiotic therapy to clear out the infection and eradicates the germs in the ear. (3)


Unexplained dizziness

The ear is not solely responsible for hearing, as it contains the vestibular system in its inner compartment.
This system is responsible for balance and coordinating movements. Consequently, patients who develop ear infections may not only complain of fever or pain but also dizziness that cannot be explained by another cause. (4)
The ENT doctor will use the otoscope to check for the integrity of the ear and the absence of any tumoral masses that could interfere with the vestibular system.


Otomycosis

Similar to otitis media, otomycosis is an infection of the middle ear that causes inflammation, itching, and malodorous discharges.

The difference between this condition and otitis media is that otomycosis is the result of fungal species overgrowth, such as Aspergillus fumigatus and Candida albicans. (5)
Otoscopes become essential to make this diagnosis, as they allow the ENT physician to observe any signs of local inflammation (e.g. swollen eardrum, pus, redness).


Earwax

Earwax, also known as cerumen, is the accumulation of a yellowish waxy substance that protects the ear from microbes and foreign objects.
However, when the quantities of earwax exceed physiological levels, patients may experience hearing impairment due to the interruption of vocal vibratory transmission.
The definitive diagnosis of this condition is assisted by otoscopes, which help the physician to locate the earwax and the degree of obstruction.


Foreign body

Often seen in kids, foreign objects may get stuck inside the ear canal, triggering inflammation and infection in the surrounding tissues.

Patients complain of otalgia (ear pain), tinnitus (ringing inside the ear), and dizziness.

Fortunately, doctors can easily diagnose this condition using an otoscope.


Contraindications of otoscope

The only documented contraindication of otoscopy is confirmed tympanic perforation (6), where the use of an otoscope may enlarge the hole even more.
The cause of this perforation might be severe otitis media or high pressure difference between the middle and the outer ear. The exposure to intense sounds that exceed the ear’s capacity may lead to tympanic rupture.
Another relative contraindication is the patient’s extreme phobia from otoscopes that can make the procedure impossible to perform.


Aside from these two factors, otoscopy is very safe and ear examination is routinely performed during checkups.

Adverse effects of using otoscopes


The medical literature seldom reports any otoscopy-induced adverse effects. (7)
However, one of the rare side effects may arise from the transmission of pathogens from one ear to another if the doctor does not carefully clean the otoscope.
As a result, patients may develop a bilateral ear infection, requiring potent antibiotics to remove the microbes.
General specifications of otoscopes
Each brand produces its own otoscope design; however, there are some specifications in common that we tried to gather.


Here are the specs of a standard otoscope:

  • Height: 19.8 CM
  • Width: 11.8 CM
  • Depth: 5.3 CM
  • Weight: 0.65 KG
  • Magnification of lens: 2.5 x
  • Diameter of ear specula 2.5 mm, 4.0 mm
  • Luminance: 24 Lumen
  • Battery type: Alkaline battery


Takeaway message

Otoscopes are an amazing invention that helped millions of patients by allowing access to an area of the ear that wouldn’t otherwise be accessible.
This process helped the prompt diagnosis of a myriad of ear conditions, including tumors, which is crucial to prevent overgrowth and metastasis.
If you have questions about otoscopy or different ear conditions, do not hesitate to ask in the comment section below.