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What is Malignant otitis externa is caused by: and explain in detail?
Ans: b (Pseudomonas) Ref: Dhingra, p. 67 & 4th ed, p. 52Malignant otitis externa (Invasive otitis externa)Aetiology: Pseudomonal infectionSusceptible: Diabetes & patients on immunosuppressive drugsC/F: Nocturnal earachePurulent otorrhoeaGranulations in the meatusComplications: Skull base osteomyelitisMultiple cranial nerve palsiesSigmoid sinus thrombosisI.O.C: Diagnostic inv - Tc 99 scanPrognostic inv - Gallium scanTreatment: Antipseudomonal antibiotics - 3rd generation cephalosporins x 6-8 wks(Ticarcillin, Tobramycin)Other important external ear conditions frequently asked are:Otomycosis & keratosis obturansOtomycosis:Aetiology: Aspergillus niger. Asp. Fumigatus, Candida albicansC/FOtoscopic: Itching, watery discharge from ear with musty odour finding: Wet cotton appearance, tissue paper appearance.Treatment: Eartoilet by syringing, suction or mopping Keep the ear dryAntifungal agents-- nystatin, clotrimazoleKeratosis obturans:Collecion of pearly white mass of desquamated epithelium in deeper meatusPathology: Failure of migration of normal epithelium of TM, onto post. Meatal wall|Collection of pearly white masses of desquamated epithelium|Bone resorption|Facial nerve exposure and paralysis|Treatment: Keratotic mass removed by syringing or instrumentationRecurrence - Keratolytic agents like 2% salicylic acid in alcohol