Chronic Suppurative Otitis

Etiology

Although viruses are the most common etiology in otitis media, bacteria often affect children with chronic suppurative otitis media. The etiology is usually polymicrobial. The most common microorganisms found in this pathology Staphylococcus aureus (MRSA). Others like are Pseudomonas aeruginosa, Proteus spp, Klebsiella spp, Bacteroides spp. and Fusobacterium spp can cause the disease. Less common are Aspergillus spp and Candida spp. which are more frequently found in patients immunocompromised.[4] Tuberculosis can also cause chronic suppurative otitis media; it is a more common cause in areas with a high incidence of tuberculosis.

Epidemiology

Chronic suppurative otitis media usually develops in early childhood, most commonly around two years of age. The children at greatest risk are the ones of low-income status.[5] This disease is also most common in children with craniofacial anomalies such as cleft palate and those born with Down syndrome. Although very rare, otitis media is present in Gradenigo syndrome, which is accompanied by orbito-facial pain and sixth cranial nerve palsy. This syndrome can occur as a complication of chronic suppurative otitis media.[6] The common feature in these congenital anomalies is a deficiency in the functioning of the Eustachian tubes, which predisposes these children to middle-ear disease. The main risk factors associated with chronic suppurative otitis media are a) frequent episodes of acute otitis media, b) upper respiratory tract infections, c) any trauma affecting the tympanic membrane, and d) poor nutrition and living conditions.[5]

Pathophysiology

In chronic suppurative otitis media, bacterial pathogens invade the mucosa of the middle ear through the external canal.[7] An inflammatory reaction occurs in the middle ear accompanied by edema and fibrosis with spontaneous perforation of the tympanic membrane and ongoing infection.

Also, chronic suppurative otitis media can occur as a complication of tympanostomy tubes inserted to treat otitis media with effusion.

Histopathology

Microscopic examination is not routinely performed in children with chronic suppurative otitis media, and it's not necessary for the diagnosis and treatment. If ear microscopy is performed, however, it will demonstrate the perforation in the drum membrane.[7]

History and Physical

Chronic suppurative otitis media presents with otorrhea most of the time, although dry ears also can be found. Symptoms that can be found but are not obligatory for diagnosis are hearing impairment, tinnitus, and aural fullness.[8] It is important to consider that children can often be asymptomatic or have a very critically ill presentation with intracranial complications. It is crucial to investigate if the patient has had vertigo and the relation with any ear complaints. All patients should be asked about their history of ear infections, recent antibiotic treatment, and surgery. Any other medical problems, such as allergic rhinitis and gastroesophageal reflux, should be noted as well as smoke exposure.[2]

Evaluation

Two types of otoscope heads can be used to evaluate the ears: 1) surgical or operating, and 2) diagnostic or pneumatic. By inspecting the ears, the degree of tympanic membrane mobility in response to negative or positive pressure can be evaluated to assess for fluid in the middle ear, a hallmark of otitis media. Other abnormalities in the tympanic membrane found are erythema, bulging or fullness, or extreme retraction. The treatment of chronic suppurative otitis media needs to be guided by a microbiologic investigation with the targeting of the microorganism according to the result. 

Pseudomonas is one of the organisms most frequently found and ubiquitous in our physical environment and has a predilection for moist areas. It is thought to infect tissues first by adherence to epithelial cells through pili or fimbriae.

Treatment / Management

Topical quinolones are the treatment of choice for chronic suppurative otitis media; they are equally or more effective as aminoglycosides and lack the risk of ototoxicity. Quinolones are effective in resolving otorrhoea and eliminating the microorganism.[9] If there is no associated cholesteatoma, parenteral antimicrobial treatment combined with assiduous aural cleansing is likely to be successful in clearing the infection, but in refractory cases, tympanomastoidectomy can be required. Beta-lactam antipseudomonal drugs such as ceftazidime are used in cases that need a parental regimen. Ticarcillin-clavulanate is an alternative agent that is effective against Pseudomonas sp. and S. aureus.(A1)

The formation of biofilm has been linked to the pathogenesis of the infection and resistance to antibiotic treatment.[5] If treated with surgery, this might have some effects preventing complications, but patients still can have ear discharge postoperatively.

If the patient does not respond to the initial treatment regimen and/or a cholesteatoma or any other mass develops, it is imperative to refer the patient to otolaryngology. When cholesteatoma is present, intervention from the otolaryngology team is required for mastoidectomy with tympanoplasty.

It is also very important to always assess hearing function and provide appropriate follow-up in all patients presenting with chronic otitis media.

Differential Diagnosis

It is important to consider other pathologies that could present with a similar clinical picture to chronic suppurative otitis media. Because otorrhea is one of the most common signs encountered in this entity and the most frequent age at presentation is usually less than 5 years, the presence of a foreign body in the ear canal needs to be ruled out. The presence of a foul-smelling odor emanating from the ear can help differentiate an otorrhea caused by a foreign body or chronic supportive otitis media. Other conditions that can be mistaken for chronic otitis media are myringitis and otitis externa (both share the signs of otorrhea), but with a physical examination, the diagnosis can be elucidated. More serious conditions that must also be ruled out are mastoiditis, abscess, and meningitis. In these cases, the presentation is more severe, and systemic symptoms are present.

• Cholesteatoma
• Petrositis
• Langerhans cell histiocytosis
• Neoplasia
• Foreign body
• Sigmoid sinus thrombosis
• Otitic hydrocephalus
• Extradural abscess
• Meningitis
• Brain abscess
• Tuberculosis
• Labyrinthitis
• Wegener granulomatosis

Toxicity and Adverse Effect Management

Aminoglycosides, although not considered the first-line treatment for chronic suppurative otitis media, is one of the choices that can be used. It is important to take into consideration the potential ototoxicity that aminoglycosides can cause.[5]

Prognosis

Overall the prognosis for chronic suppurative otitis media is good if treatment is provided and complications are avoided. Some refractory cases can be found, and these require more extensive evaluation and treatment. Because chronic suppurative otitis media is most of the time followed by acute otitis media, it's important to diagnose and treat the bacterial cause of acute otitis media to prevent chronic suppurative otitis media. The introduction of the Pneumococcus vaccine has shown a positive effect in decreasing the incidence of acute otitis media, which leads to a reduction of cases presenting with chronic suppurative otitis media.[5]

Complications

Multiple complications can result from chronic suppurative otitis media such as polyps, osteitis, sclerosis, tympanosclerosis, labyrinthitis, and intracranial suppurative complications such as epidural, subdural, or brain abscesses. The most common complication is hearing loss, either conductive or sensorineural. Hearing loss is associated with language delays and behavioral problems.[10]