Malignant Otitis Externa Risk Factors

Diabetes Mellitus is the most significant risk factor for Malignant Otitis Externa (MOE), present in up to 90% of patients due to small-vessel vasculopathy and impaired immune function. This predisposition is primarily due to the presence of a chronic wound or inflammatory process, which can provide a portal of entry for bacteria to cause infection. Additionally, immunodeficiencies, such as lymphoproliferative disorders or medication-related immunosuppression, can also exacerbate the risk of developing MOE.

Moeschi and colleagues found that aural irrigation is a significant predisposing factor for MOE, with up to 50% of cases reported to be preceded by traumatic aural irrigation in patients with diabetes. The authors suggest that the trauma caused by aural irrigation can disrupt the skin and mucous membranes of the ear canal, allowing bacteria to penetrate and cause infection.

Pseudomonas aeruginosa is the most common causative pathogen in MOE, accounting for approximately 47% of cases. However, other organisms, such as Staphylococcus aureus, Klebsiella, and Proteus mirabilis, have also been reported as causative agents. These pathogens can cause a range of symptoms, including discharge, pain, and fever, and can spread to other parts of the head and neck, including the brain and eye.

The complications of MOE can be severe and life-threatening. Facial nerve palsy is a common complication, associated with a poorer prognosis. Intracranial complications, such as meningitis, brain abscess, thrombophlebitis of the lateral sinus, extradural abscess, and otitic hydrocephalus, can occur, and can be fatal if left untreated.

Cholesteatoma is a complication of MOE that can occur when a combination of factors, including a chronic inflammatory process, a predisposing factor such as otitis media, and a compromised immune system, come together to create an ideal environment for bacterial growth. The pathogenesis of cholesteatoma involves the accumulation of keratin debris in the middle ear cleft, which can become infected and lead to a range of complications, including intracranial sepsis and abscesses.

The ear is a complex organ that plays a vital role in our ability to hear and maintain balance. The structures of the medial wall of the ear include the oval window, round window, and promontory, which work together to transmit sound vibrations to the inner ear. The facial nerve motor branches innervate the muscles of facial expression, while the sensory branches provide sensation to the anterior two-thirds of the tongue and the skin of the external ear.

Upper motor neuron lesions (UMNL) result in contralateral facial paralysis, while lower motor neuron lesions (LMNL) result in ipsilateral facial paralysis. Longitudinal fractures typically involve the otic capsule and can result in hearing loss, while transverse fractures are more likely to cause facial nerve paralysis. Chronic safe cholesteatoma is limited to the middle ear, while chronic unsafe cholesteatoma can erode into the mastoid and cause complications.

Acoustic neuroma is a tumor of the eighth cranial nerve, while Ménière's disease is a disorder of the inner ear that can cause vertigo, hearing loss, and tinnitus. Pathological perforations are typically caused by chronic otitis media, while traumatic perforations are caused by acute injury to the tympanic membrane.

Sinusitis is a common condition that affects the paranasal sinuses, which are air-filled cavities in the skull. Complications of sinusitis include orbital complications, intracranial complications (e.g., meningitis, brain abscess), and osteomyelitis of the frontal or sphenoid bones. The treatment of choanal atresia typically involves surgical correction, either by transnasal or transpalatal approaches.

The pharynx is a tube-like structure that extends from the base of the skull to the esophagus, and plays a vital role in the transport of food and air from the mouth to the stomach and lungs. The contents of the parapharyngeal space include the internal carotid artery, internal jugular vein, cranial nerves IX-XII, and lymph nodes. The blood supply to the pharynx is primarily from the external carotid artery, including the ascending pharyngeal, facial, and lingual arteries.

The blood supply to the tonsils is from the tonsillar branches of the facial and lingual arteries. Complications of tonsillitis include peritonsillar abscess (quinsy), cervical lymphadenitis, and airway obstruction. The causes of quinsy include bacterial infections, typically Streptococcus pyogenes or Staphylococcus aureus. The complications of quinsy include airway obstruction,

Learn about the causes and predisposing factors of Malignant Otitis Externa, including diabetes and immunodeficiencies.