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::Incorrect - This describes Staphylococcus Aureus, which is responsible for cutaneous infections, particularly staph scalded skin syndrome.
Answer B	AnswerB::Dimorphic fungus
Answer B Explanation	AnswerBExp::Incorrect- This describes Candida Albicans, which is responsible for yeast infections.
Answer C	AnswerC::Gram negative rod, maltose fermenter
Answer C Explanation	AnswerCExp::Incorrect - 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::Incorrect - 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::Correct - See Explanation
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. Educational Objective: Ectopic pregnancy is caused by Pelvic Inflammatory Disease. The most common cause of Pelvic Inflammatory Disease is Neisseria Gonnorhea, a gram negative rod. References: First Aid 2012 page 202 Educational Objective: References: ]]
Approved	Approved::Yes
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