WBR0061
| Author | PageAuthor::William J Gibson |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology |
| Sub Category | SubCategory::Reproductive, SubCategory::General Principles, SubCategory::Infectious Disease |
| Prompt | [[Prompt::A 29-year-old female presents to the emergency room with the acute onset of right lower quadrant pain. She describes the pain as constant as opposed to colicky. Ultrasound demonstrates an adnexal mass. Her last menstrual period was 7 weeks ago. If an infection was responsible for the patient developing this condition, which of the following describes the most likely causal organism?]] |
| Answer A | AnswerA::Gram positive cocci, catalase positive |
| Answer A Explanation | AnswerAExp::This describes Staphylococcus aureus, which is responsible for cutaneous infections, particularly staph scalded skin syndrome. |
| Answer B | AnswerB::Dimorphic fungus |
| Answer B Explanation | AnswerBExp::This describes Candida albicans, which is responsible for yeast infections. |
| Answer C | AnswerC::Gram negative rod, maltose fermenter |
| Answer C Explanation | AnswerCExp::This describes Neisseria meningitidis which is responsible for bacterial meningitis in older adults |
| Answer D | AnswerD::Gram positive cocci, catalase negative |
| Answer D Explanation | AnswerDExp::This describes Streptococcus pneumoniae which is the most common cause of community acquired pneumoniae |
| Answer E | AnswerE::Gram negative rod, maltose nonfermenter |
| Answer E Explanation | AnswerEExp::The most common cause of pelvic inflammatory disease is Neisseria gonnorhea, a gram negative rod. |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::The patient in this vignette is presenting with a history consistent with ectopic pregnancy. Ectopic pregnancy occurs when an egg is fertilized and implants outside of the uterus, most commonly in the fallopian tube. These pregnancies are not viable, but represent a significant health risk to the mother. Early on, ectopic pregnancies can present with pain in the lower abdomen or during urination. Sometimes mild vaginal bleeding can occur due to poor progesterone production by the corpus luteum and therefore withdrawal of the uterine lining. However, late ectopic pregnancies almost always present with significant pain and either vaginal or internal bleeding. These patients often present with symptoms similar to appendicitis. Lower abdominal or back pain is caused by a ruptured fallopian tube causing sometimes life-threatening internal bleeding.
 One of the main risk factors for ectopic pregnancy is pelvic inflammatory disease (PID). PID causes salpingitis or inflammation of the fallopian tubes, which can lead to scarring if untreated. The scarring of the fallopian tube serves as a nidus for inappropriate implantation. Ectopic pregnancy rarely occurs with active PID. The most common cause of PID is untreated infection with either Neisseria gonnorhea (65%) or Chlamydia trachomatis (10%). Neisseria gonnorhea is a gram negative rod which can be treated with ceftriaxone. First Aid 2012 page 202]] |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Pregnancy, WBRKeyword::Ectopic pregnancy, WBRKeyword::Microbiology, WBRKeyword::Bacteria, WBRKeyword::Infection, WBRKeyword::Abdominal pain, WBRKeyword::Pelvic inflammatory disease |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |