Most common cause of orbital cellulitis is?
High-Yield Explanation
ANSWER: (C) S. aureusREF: With textBacterial orbital cellulitis is a life-threatening infection of the soft tissues behind the orbital septum. It can occur at any age but is more common in children. The most common causative organisms are S. pneumoniae, S. aureus, S. pyogenes and H. Influenzae. (Ref: Khurana 4th ed page 385, Kanski 7th ed chapter 3)The major causes of orbital cellulitis are sinusitis (58%), lid or face infection (28%), foreign body (11%), and hematogenous (4%). Staphylococcus andStreptococcus are the most common causative organisms in adults, Haemophilus influenzae in children. Less common organisms are Pseudomonas and Escherichia coli. (Ref: Yanoff 2nd ed page 739)H. influenza type b has been the most common pathogen responsible for Orbital cellulitis prior to the advent of its vaccine. Currently Staphylococcus is the most common bacterial isolate. (Ref: Oculoplastics and Orbit: Aesthetic and Functional Oculofacial Volume 3 ByRudolf R Guthoff, James Katowitz page 151)Option (D); Rhino-orbital mucormycosis: Mucormycosis is a very rare opportunistic infection caused by fungi of the family Mucoraceae, which typically affects patients with diabetic ketoacidosis or immunosuppression. (Ref: Kanski 7th ed chapter 3)