Malignant external otitis

Malignant external otitis

    * Introduction
    * Signs and symptoms
    * Diagnosis
    * Treatment
Necrotizing otitis externa or malignant otitis is an infection involving the temporal bone and adjacent a relatively rare complication of external otitis. Occurs mainly in immunocompromised individuals, the elderly with diabetes and is initiated by trauma to the external auditory canal. The most common pathogen is Pseudomonas aeruginosa. Patients with malignant external otitis accused severe ear pain that gets worse at night and otoree. Clinical elements include the development of granulation tissue in the external ear canal, especially the bone-cartilage junction. Facial paralysis and other cranial nerves indicates a negative prognosis, intracranial complications are the most common cause of death.
Diagnosis requires the cultivation of secretions from the ear and anatomopathological examination of granulation tissue at the site of infection. Imaging studies include CT scan, bone scintigraphy with technetium 99 medronat sig alum citrate 67.
Treatment includes correction of immunosuppression when possible, local treatment of auditory canal, long systemic antibiotic therapy and surgery in selected patients. Patients should be educated to avoid manipulation succeptibili canal by using cotton buds and ear canal to minimize exposure to high concentrations of chloride.
Pathogenesis and causes:
Soft tissue infection or swimmer's ear canal external autidiv is common, especially in humid and warm climates. Trigger events are usually self-inflicted trauma by cleaning her ears with sticks and exposure to swimming pool water that has high concentrations of halogens. The most commonly cultured pathogen Pseudomonas aeruginosa is not normally found in a canal. Other potential pathogens include Staphylococcus epidermidis, gram-negative bacteria and fungi. Patients with otitis externa and ear pain sensitivity accused ear movements. Otorea may be present and the obliteration of the ear canal can cause hearing loss and watery swelling or a feeling of fullness in the ear. The infection can spread to cartilaginous skeleton of the canal and through the temporal bone fractures Snatorini cauzins osteitis. A mark of this extension is granulation tissue at the bone cartilage junction of the external auditory canal. This element is critically important otoscope. Because of significant differences between natural evolution and treatment is crucial differentiating severe external otitis malignant otitis externa. Involvement of deeper soft tissues of the ear canal occurs only in malignant form. Skull base osteitis secondary external otitis but may be due to infections and middle ear.
Although malignant otitis externa can occur in immunocompetent persons develop typical in those with diabetes or other conditions that affect the immune system as gained immunodeficiency syndrome, neoplasia or chemotherapy. The contribution of diabetes cause poor vascular disease exacerbated by the vasculitis microvascular pseudomonala further restricting circulation. Diabetes is associated with impaired function of polymorphonuclear and high pH of cerumen in the ear canal. These factors along with the sensitivity of Pseudomonas aeruginosa to low pH restricts body defense against infection. Patients with skull base osteitis extraauriculare events sometimes have as cervical lymphadenopathy, trismus due to temporomandibular joint involvement or irritation of the masseter muscle. As the infection spreads to the temporal bone and can cause paralysis extends to the skull and cranial nerves. Paralysis is usually caused by the secretion of neurotoxins or destructive effect of the process through the foramen compression. Due to its location in temporal bone anatomy, the facial nerve is the nerve that is usually affected first.