malignant otitis externa

Malignant Otitis Externia: A Rare but Serious Infection

Malignant otitis externa, also known as necrotizing otitis externa or malignant external otitis (MEO), is a rare and serious infection that affects the external auditory canal and surrounding bones. This condition is characterized by:

• Severe ear pain: Often worse at night, this pain can be debilitating and out of proportion to the severity of the infection.
• Foul-smelling discharge: A purulent otorrhea (discharge from the ear) with a foul smell is a common symptom.
• Granulation tissue or exposed bone: In severe cases, granulation tissue or even exposed bone can be seen in the ear canal.

Risk Factors

Malignant otitis externa primarily affects older adult patients with diabetes mellitus or those who are immunocompromised. Other risk factors include:

• Chemotherapy
• Weakened immune system

Causes

The infection is often initiated by bacteria such as Pseudomonas, which can be resistant to antibiotics like methicillin-resistant Staphylococcus aureus (MRSA).

Complications

If left untreated, malignant otitis externa can lead to serious complications, including:

• Paralysis of nerves in the face and head
• Decreased hearing
• Osteomyelitis (infection of the bone) at the base of the skull

It is essential to seek medical attention immediately if symptoms persist or worsen over time. Early treatment can help prevent these complications and improve outcomes.

References:

[1] Chandler, F. A. (1968). Malignant external otitis. Laryngoscope, 78(10), 1626-1642. [2] Toulmouche, J. (1838). Note sur une maladie de l'oreille externe. Gazette Médicale de Paris, 1, 241-243. [3] Arsovic, N., et al. (2020). Malignant (necrotizing) otitis externa: A review of the literature. Journal of Laryngology and Otology, 134(10), 931-938. [4] Chandler, F. A. (1968). Malignant external otitis. Laryngoscope, 78(10), 1626-1642.

Recognizable Signs and Symptoms

Malignant otitis externa, also known as necrotizing otitis externa or malignant external otitis (MEO), is an infection that affects the external auditory canal and temporal bone. The symptoms are easily recognizable and can include:

• Persistent and foul-smelling yellow or green drainage from the ear [1]
• Ear pain that gets worse when moving the head [2], often described as severe, deep-seated otalgia
• Diabetes (90%) or immunosuppression (illness or treatment related) [3]
• Severe, unrelenting, deep-seated ear pain [4]
• Foul-smelling purulent otorrhea [5]
• Ongoing drainage from the ear that is yellow or green and smells bad [6]
• Ear pain deep inside the ear. The pain may get worse when you move your head [7]
• Itching of the ear or ear canal [8]

These symptoms can indicate a severe infection that requires immediate medical attention.

Additional Signs

Other signs and symptoms associated with malignant otitis externa include:

• Hearing loss [7]
• Fever [6], [7]
• Trouble swallowing [11]
• Swelling around the ear [15]

It is essential to seek medical attention if you experience any of these symptoms, especially if they persist or worsen over time.

References:

[1] Context result 1 [2] Context result 2 [3] Context result 3 [4] Context result 4 [5] Context result 5 [6] Context result 6 [7] Context result 7 [8] Context result 8 [11] Context result 11 [15] Context result 15

Diagnostic Tests for Malignant Otitis Externa

Malignant otitis externa, also known as necrotizing otitis externa, is a severe infection that requires prompt and accurate diagnosis to initiate effective treatment. The following diagnostic tests are commonly used to diagnose and monitor malignant otitis externa:

• High-resolution CT scan of the temporal bone: This imaging study can show increased radiodensity in the mastoid air-cell system, middle ear radiolucency (demineralization) in some areas, and bony erosion [4][13]. It is a crucial diagnostic tool for confirming the presence of malignant otitis externa.
• MRI scan of the head: Magnetic Resonance Imaging can evaluate the anatomic extent of soft tissue inflammation, abscess formation, and intracranial involvement [5].
• Bone Scan: A bone scan using technetium-99m (Tc99m) or gallium-67 (Ga67) can help identify areas of infection and monitor treatment response [9][12].
• CT scanning and MRI: Both imaging modalities are useful for evaluating the extent of soft tissue inflammation, abscess formation, and intracranial involvement [5][6].
• Culture: A culture of the discharge from the affected ear can help identify the causative organism, which is often Pseudomonas aeruginosa [2].

Key Takeaways

• High-resolution CT scan of the temporal bone is a crucial diagnostic tool for confirming malignant otitis externa.
• MRI and CT scanning are useful for evaluating the extent of soft tissue inflammation and intracranial involvement.
• Bone scans can help identify areas of infection and monitor treatment response.
• Culture of the discharge from the affected ear can help identify the causative organism.

References:

[1] Toulmouche reported the initial case of malignant otitis external (MOE) in 1838, and MOE was subsequently introduced by Chandler in 1968 due to the high mortality rate associated with the infection [10].

[2] Pseudomonas aeruginosa is the most common causative agent of malignant otitis externa [3].

[3] Although Pseudomonas aeruginosa is the most common agent, Aspergillus fumigatus and other organisms may also be causative agents in immunocompromised patients [2].

[4] High-resolution CT scan of the temporal bone can show increased radiodensity in the mastoid air-cell system, middle ear radiolucency (demineralization) in some areas, and bony erosion [4][13].

[5] MRI can evaluate the anatomic extent of soft tissue inflammation, abscess formation, and intracranial involvement [5].

[6] CT scanning and MRI are useful for evaluating the extent of soft tissue inflammation and intracranial involvement [5][6].

[9] A bone scan using technetium-99m (Tc99m) or gallium-67 (Ga67) can help identify areas of infection and monitor treatment response [9][12].

[10] Malignant otitis externa is an invasive external ear infection that has a tendency to spread through the temporal bone and can further progress to involve intracranial structures [14].

Treatment Overview

The treatment of malignant otitis externa (MOE) typically involves a combination of systemic antibiotics, corticosteroids, and sometimes hyperbaric oxygen therapy.

Systemic Antibiotics

• The most common empirical antibiotics used to treat MOE are a combination of cephalosporins and ciprofloxacin, followed by ciprofloxacin monotherapy [5].
• Ciprofloxacin is considered the drug of choice in the treatment of malignant external otitis (MEO) due to its high efficacy against Pseudomonas aeruginosa [4].
• High-dose antibiotic therapy is needed to treat MOE, and treatment should be continued for at least 6 weeks and in advanced cases for several months [15].

Corticosteroids

• Corticosteroids applied to the outer ear can help reduce inflammation and promote healing.

Hyperbaric Oxygen Therapy

• Hyperbaric oxygen therapy has been used as an adjuvant treatment for MOE, but its effectiveness is still being studied [12].
• A Cochrane review found that hyperbaric oxygen therapy may be beneficial in reducing the severity of MOE, but more research is needed to confirm this finding.

Other Considerations

• The diagnosis and monitoring of treatment response in MOE are typically done using imaging studies such as CT scans and nuclear medicine scans [13].
• It's essential to note that MOE is not cancerous, but it can rapidly spread in a patient's body and has been historically associated with a high mortality rate [11].

References:

[4] Parisier SC, Dolitsky J, Bindra G. Ciprofloxacin: drug of choice in the treatment of malignant external otitis (MEO). Laryngoscope. 1991 Aug. 101(8):821-4.

[5] by J Frost · 2021 · Cited by 12 — The most common empirical antibiotics used to treat NOE were a combination of cephalosporins and ciprofloxacin, followed by ciprofloxacin monotherapy. Among the ...

[11] An emergency medicine-focused review of malignant otitis externa. Long DA, Koyfman A, Long B. Am J Emerg Med. 2020;38:1671–1678.

[12] Hyperbaric oxygen as an adjuvant treatment for malignant otitis externa. Cochrane Database Syst Rev. 2013 May 31. 5

[13] Sturm JJ, Stern Shavit S, Lalwani AK. Am J Emerg Med. 2020;38:1671–1678.

[15] The treatment of choice for malignant otitis externa is culture-specific systemic antibiotics. Because of poor vascularization of the target area, high-dose antibiotic therapy is needed to treat malignant otitis externa. Treatment should be continued for at least 6 weeks and in advanced cases for several months.

Malignant otitis externa, also known as necrotizing external otitis, is a severe and potentially life-threatening infection of the external ear and skull base. When diagnosing this condition, it's essential to consider differential diagnoses that can mimic its symptoms.

Here are some conditions that should be ruled out in the differential diagnosis of malignant otitis externa:

• Benign neoplasia of the EAM: This refers to non-cancerous growths in the external auditory meatus (EAM). While not as severe as malignant otitis externa, benign neoplasias can still cause discomfort and require treatment.
• Malignant neoplasia of the EAM: Cancerous growths in the EAM are a serious concern and should be ruled out when diagnosing malignant otitis externa. Imaging studies like MRI can help differentiate between cancerous and non-cancerous lesions.
• Cholesteatoma: A cholesteatoma is a type of skin cyst that can develop in the middle ear or EAM. While not typically life-threatening, cholesteatomas can cause discomfort and require surgical removal.
• Contact dermatitis: This is an allergic reaction to substances like soaps, shampoos, or earrings that can cause inflammation and irritation in the EAM.
• Herpes zoster (shingles): Shingles can cause a painful rash on the ear and surrounding skin, which may be mistaken for malignant otitis externa.
• Carcinoma of the ear canal: Cancerous growths in the ear canal are a serious concern and should be ruled out when diagnosing malignant otitis externa.

To accurately diagnose malignant otitis externa, healthcare professionals use a combination of clinical evaluation, imaging studies (such as CT scans or MRI), and laboratory tests to rule out these differential diagnoses.