WBR0208
| Author | PageAuthor::Mugilan Poongkunran |
|---|---|
| Exam Type | ExamType::USMLE Step 3 |
| Main Category | MainCategory::Primary Care Office |
| Sub Category | SubCategory::Infectious Disease, SubCategory::Musculoskeletal/Rheumatology |
| Prompt | [[Prompt::27 year old male presents to the office with several day history of joint pain. He says he has never had such pain before. His past medical history is insignificant and also has tried over the counter ibuprofen but it has not helped his pain. He is a smoker and alcoholic. He uses marijuana occasionally but denies any injectable drug use. He is sexually active and uses condoms. He has no recent travel outside the country and has no allergies. Physical examinations show mild hyperemia and swelling in the right knee and right ankle. Range of movements is restricted because of pain. No rash is present. Arthrocentesis done shows a turbid fluid with WBC count of 20,000/mm3. What is the best next step to confirm the diagnosis?
A. Joint fluid culture B. Culture from joint fluid, urethra and oral cavity C. Blood culture D. RA factor E. Chemistry study of joint fluid culture]] |
| Answer A | AnswerA::Joint fluid culture |
| Answer A Explanation | AnswerAExp::'''Incorrect''' : Joint fluid culture alone would be positive only in 50% of individuals with gonococcal arthritis. |
| Answer B | AnswerB::Culture from joint fluid, urethra and oral cavity |
| Answer B Explanation | AnswerBExp::'''Correct''' : Culture of joint fluid and other mucosal surfaces would be diagnostic in 80% of individuals. |
| Answer C | AnswerC::Blood culture |
| Answer C Explanation | AnswerCExp::'''Incorrect''' : Patients with the tenosynovitis, dermatitis, polyarthralgia form of DGI are more likely to have positive blood cultures than those presenting with purulent arthritis. |
| Answer D | AnswerD::RA factor |
| Answer D Explanation | [[AnswerDExp::Incorrect : Patients with the constellation of reactive arthritis, tenosynovitis, and urethritis (formerly Reiter syndrome), unlike those with typical DGI, also have one or more of the following: conjunctivitis; circinate balanitis; or keratoderma blenorrhagicum.]] |
| Answer E | AnswerE::Chemistry study of joint fluid culture |
| Answer E Explanation | [[AnswerEExp::Incorrect : Chemistry studies of the joint fluid, such as the concentrations of glucose, lactate dehydrogenase, or protein have only limited value; a reduction in glucose concentration and elevation of LDH are consistent with a bacterial infection, but are not diagnostic or particularly sensitive.]] |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::Disseminated gonococcal infection (DGI) results from bacteremic spread of the sexually transmitted pathogen, neisseria gonorrhoeae, which can lead to a variety of clinical symptoms and signs, such as tenosynovitis, dermatitis, and multiple skin lesions. It should be suspected in sexually active individuals with mono or oligoarthritis. Culture of joint fluid and other mucosal surfaces would be diagnostic in 80% of individuals. The mean synovial fluid leukocyte count in gonococcal arthritis is typically around 50,000 cells/mm3; in some cases, however, cell counts below 10,000 cells/mm3 may be observed. Educational Objective: |
| Approved | Approved::Yes |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |