A patient presents with watery diarrhea, abdominal cramps, and nausea after consuming contaminated water from a stream during a camping trip. Laboratory tests reveal oocysts in the stool sample. Which of the following parasites is most likely responsible for this infection?

Correct Answer: C

Rationale: Cryptosporidium parvum is a parasite commonly found in contaminated water sources such as streams or lakes. It causes an infection called cryptosporidiosis, which often presents with symptoms like watery diarrhea, abdominal cramps, and nausea. The oocysts of Cryptosporidium parvum can be identified in stool samples, making it the likely culprit in this scenario. Giardia lamblia, another common waterborne parasite, can also cause similar symptoms but is characterized by trophozoites rather than oocysts in stool samples. Entamoeba histolytica is associated with amoebic dysentery and does not typically present with watery diarrhea. Cyclospora cayetanensis is another parasite causing gastrointestinal symptoms but is not as commonly associated with contaminated water sources as Cryptosporidium parvum.

Correct Answer: A

Rationale: The clinical presentation of severe lower abdominal pain and vaginal bleeding in a pregnant woman, along with cervical motion tenderness, unilateral adnexal tenderness, and an adnexal mass on the affected side, is highly concerning for an ectopic pregnancy. Ectopic pregnancy occurs when a fertilized egg implants outside the uterus, most commonly in the fallopian tube. The presence of an adnexal mass and tenderness on one side is indicative of potential tubal involvement and can mimic symptoms of pelvic inflammatory disease. Prompt evaluation and management are crucial in ectopic pregnancy to prevent life-threatening complications associated with rupture of the fallopian tube.

Correct Answer: B

Rationale: Meconium-stained amniotic fluid indicates that the fetus may have passed stool in utero, which can lead to potential respiratory problems once born due to meconium aspiration. The priority action for the nurse in this situation is to prepare for immediate delivery to expedite the removal of the fetus from the contaminated environment and provide necessary interventions such as suctioning of the airway to prevent aspiration of meconium. Prompt delivery is crucial to minimize the risk of complications related to meconium aspiration syndrome. Administering oxygen, inserting a urinary catheter, and notifying the neonatal resuscitation team can be important subsequent actions, but the immediate focus should be on delivering the baby.

Correct Answer: B

Rationale: Urticaria (hives) and pruritus (itching) are common signs of an allergic reaction to antibiotics, including those used for GBS prophylaxis during labor. Other signs of an adverse reaction may include flushing, fever, chills, and anaphylaxis. It is important to monitor the woman closely for any signs of an allergic reaction and to intervene promptly if one occurs to ensure the safety of both the mother and the baby.

Correct Answer: B

Rationale: In the case of umbilical cord prolapse, the priority nursing action is to prepare for an immediate cesarean section. Umbilical cord prolapse is a serious obstetric emergency where the umbilical cord slips through the cervix ahead of the presenting part of the fetus. This can lead to compression of the cord, compromising fetal blood flow and oxygenation. Immediate delivery via cesarean section is necessary in order to prevent fetal hypoxia and avoid potential complications such as brain damage or death. Elevating the mother's hips or administering intravenous fluids rapidly may be interventions done in conjunction with preparing for a cesarean section, but the priority remains expedited delivery of the baby. Applying external fetal monitoring is not the most appropriate action in this emergency situation.