Which of the following conditions is characterized by the formation of calcium oxalate or calcium phosphate stones within the renal collecting system?

Correct Answer: D

Rationale: Nephrolithiasis refers to the formation of stones within the kidney or urinary tract. The most common types of kidney stones are either composed of calcium oxalate or calcium phosphate. When these stones form within the renal collecting system, they can lead to symptoms such as flank pain, hematuria, and urinary obstruction. Ureteropelvic junction (UPJ) obstruction and ureterovesical junction (UVJ) obstruction are specific types of blockages within the urinary system that can be caused by kidney stones but are not characteristic of the stone formation itself. Renal colic is the term used to describe the severe pain associated with the passage of a kidney stone through the ureter.

Correct Answer: C

Rationale: The clinical presentation described with fever, headache, maculopapular rash starting on the face and spreading to the trunk and extremities, along with leukopenia and thrombocytopenia suggests a likely diagnosis of Rocky Mountain spotted fever (RMSF), which is caused by the bacterium Rickettsia rickettsii.

Correct Answer: D

Rationale: Incompetent cervix, also known as cervical insufficiency, is the most likely cause of the symptoms described. Incompetent cervix is a condition where the cervix begins to dilate and efface prematurely, typically in the second trimester, without contractions or labor. This can lead to painless cervical dilation and bulging of the amniotic sac into the vagina, which can cause vaginal bleeding and crampy abdominal pain. It is a leading cause of second-trimester pregnancy loss. Treatment may involve a cervical cerclage, a surgical procedure where the cervix is stitched closed to provide additional support.

Correct Answer: C

Rationale: Uterine rupture is a serious obstetric emergency that involves a tear or rupture of the uterine wall during pregnancy. In this scenario, the pregnant woman with severe lower abdominal pain, vaginal bleeding, and a tender, distended abdomen is showing signs consistent with uterine rupture. These symptoms are typically not seen with other conditions listed.

Correct Answer: B

Rationale: When a woman in active labor is receiving intravenous oxytocin for labor augmentation, it is essential to increase the oxytocin infusion rate gradually to prevent oxytocin-induced uterine hyperstimulation. Uterine hyperstimulation can lead to complications such as fetal distress, uterine rupture, and postpartum hemorrhage. By increasing the oxytocin infusion rate gradually, the uterus has more time to adapt to the medication and reduces the risk of hyperstimulation. It is crucial for the healthcare provider to carefully monitor the woman's response to oxytocin and adjust the infusion rate as needed to ensure safe and effective labor augmentation. Monitoring for signs of uterine hyperstimulation, such as persistent contractions close together or excessive uterine activity, is crucial in preventing complications and ensuring the well-being of both the mother and baby.