In septic arthritis of the hip in adults, which organism is the MOST common causative agent in a sexually active 25-year-old?
- A Staphylococcus aureus
- B Neisseria gonorrhoeae ✓
- C Streptococcus pyogenes
- D Haemophilus influenzae
Correct answer: B. Neisseria gonorrhoeae
Explanation
In sexually active young adults (15-40 years), Neisseria gonorrhoeae is the most common cause of septic arthritis, accounting for up to 75% of cases in this demographic. Gonococcal arthritis often presents as a migratory polyarthritis, dermatitis, and tenosynovitis triad before monoarticular septic arthritis ensues. Staphylococcus aureus is the most common overall in all age groups and predominates in children, elderly, and IV drug users. Haemophilus influenzae was common in children <2 years before routine vaccination.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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