This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
[{'content': 'A 65-year-old diabetic presents with necrosis of the external auditory meatus with foul smelling discharge. The probable organism associated with the condition is \nSelect and explain. \nA. Haemophilus influenzae, B. Streptococcus pyogenes, C. Pseudomonas aeruginosa, D. E. Coli', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Malignant Otitis externa o Malignant otitis externa,\nalso called necrotizing external otitis, is a misnomer as it is not a neoplastic condition, rather it is an infectious condition.\nMalignant otitis externa is a disorder involving inflammation and damage of the bones and cartilage at the base of the skull in temporal bone as a result of the spread of infection from the outer ear.\nMalignant otitis externa is often caused by difficult to treat bacteria such as Pseudomonas aeruginosa.\nOnly rare cases of malignant otitis externa due to S.aureus, Proteus mirabilis and Aspergillus fumigatus have been reported.\nThe infection spreads from the floor of the ear canal to the nearby tissues and into the bones at the base of the skull.\nThe infection and inflammation may damage or destroy the bones. The infection may spread more and affect the cranial nerves, brain, or other parts of the body. Predisposing factors for malignant otitis externa o Elderly diabetics (most common predisposing factor)\n\xa0Individuals with altered immune function (immunodeficiency)\n\nChemotherapy Clinical features of malignant otitis externa\n\nThe severe pain inside the ear and may get worse when moving the head.\n\nGranulation tissue in the external auditory canal,\n\nat the junction of a bony and cartilaginous part\n\nDrainage from the ear - yellow, yellow-green, foul-smelling, persistent\n\nFever o Itching of the ear or ear canal\n\nTroubled swallowing & weakness of face.\n\nComplications \xa0Cranial nerve palsies most commonly facial nerve is involved.\nOther cranial nerves can also be involved (glossopharyngeal, vagus, spinal accessory, hypoglossal,\nabducens, trigeminal),\n\nJugular venous thrombosis \xa0Cavernous sinus thrombosis \xa0Meningitis Treatment of malignant otitis externa \xa0In all cases,\n\nthe external ear canal is cleansed and a biopsy specimen of the granulation tissue sent for culture. IV antibiotics are directed against the offending organism.\nFor Pseudomonas aeruginosa, the most common pathogen,\nthe regimen involves an antipseudomonal penicillin or cephalosporin (3rd generation piperacillin or ceftazidime) with an aminoglycoside.\nA fluoroquinolone antibiotic can be used in place of the aminoglycoside.\nEar drops containing antipseudomonal antibiotic e.g. ciprofloxacin plus a glucocorticoid is also used. Early cases can be managed with oral and otic fluoroquinolones only.\nExtensive surgical debridement once an important part of the treatment is now rarely needed.', 'role': 'assistant'}]