A 28-year-old woman, gravida 1 para 0, at 34 weeks gestation comes to the emergency department due to sudden-onset lower abdominal pain. The patient initially had intermittent flank pain over the past 4 days that improved with acetaminophen. For the last 2 hours, she has had excruciating pain in the right flank that radiates to her groin. She has had some irregular contractions but no vaginal bleeding or leakage of fluid. Fetal movement is normal. Her pregnancy has been uncomplicated, and she has no chronic medical conditions. Temperature is 37.5 C (99.5 F), blood pressure is 130/86 mm Hg, and pulse is 98/min. Fetal heart rate tracing shows a baseline of 155/min, moderate variability, multiple accelerations, and no decelerations. Tocodynamometer reveals irregular contractions every 7-15 minutes. There is tenderness to palpation over the right flank and right inguinal region. The uterus is nontender and the cervix is closed. Urinalysis shows moderate blood but is negative for white blood cells, leukocyte esterase, and nitrites. Which of the following is the best next step in management of this patient?

Question

A 28-year-old woman, gravida 1 para 0, at 34 weeks gestation comes to the emergency department due to sudden-onset lower abdominal pain.  The patient initially had intermittent flank pain over the past 4 days that improved with acetaminophen.  For the last 2 hours, she has had excruciating pain in the right flank that radiates to her groin.  She has had some irregular contractions but no vaginal bleeding or leakage of fluid.  Fetal movement is normal.  Her pregnancy has been uncomplicated, and she has no chronic medical conditions.  Temperature is 37.5 C (99.5 F), blood pressure is 130/86 mm Hg, and pulse is 98/min.  Fetal heart rate tracing shows a baseline of 155/min, moderate variability, multiple accelerations, and no decelerations.  Tocodynamometer reveals irregular contractions every 7-15 minutes.  There is tenderness to palpation over the right flank and right inguinal region.  The uterus is nontender and the cervix is closed.  Urinalysis shows moderate blood but is negative for white blood cells, leukocyte esterase, and nitrites.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_da9b_2489_bc81_a1285d50134c_MD0003_00 This patient most likely has symptomatic nephrolithiasis (ie, kidney stones). Nephrolithiasis typically occurs during the second and third trimesters because pregnancy causes progesterone-induced urinary stasis and increases urinary calcium excretion. As the stone travels the course of the ureter, it causes intermittent obstruction (eg, intermittent flank pain that radiates to the groin) and epithelial damage (eg, hematuria). Some patients develop irregular contractions due to the proximity of the uterus to the inflamed ureter. Most patients with suspected nephrolithiasis undergo CT scan of the abdomen and pelvis; however, during pregnancy, this imaging may expose the fetus to radiation. Although the highest risk of fetal injury is in the first trimester, radiation should be limited throughout pregnancy to avoid fetal complications (eg, microcephaly, growth restriction). Therefore, pregnant women with suspected nephrolithiasis undergo ultrasound of the kidney and ureters because of the low risk of fetal radiation exposure. Treatment is supportive (eg, pain control, hydration) because most stones pass spontaneously. Patients with complicated nephrolithiasis (eg, sepsis, obstruction) may require additional management with cystoscopy and possible stent placement. (Choice A) A 24-hour urine collection for protein is used to evaluate for preeclampsia as a measure of end-organ damage. This patient does not have preeclampsia because her blood pressure is normal for pregnancy (ie, <140/90 mm Hg). (Choice B) Betamethasone, a corticosteroid used to promote fetal lung maturity, and indomethacin, a tocolytic, are administered to patients in preterm labor (ie, regular, painful contractions that cause cervical dilation). Although nephrolithiasis can cause preterm labor, this patient has irregular contractions and a closed cervix. In addition, indomethacin is contraindicated after 32 weeks gestation due to the risk of premature closure of the fetal ductus arteriosus. (Choice C) CT scans are relatively contraindicated in pregnancy because of the risk of fetal radiation exposure. Limited low-dose CT scans may be considered in the second and third trimesters if safer imaging modalities (eg, ultrasound, MRI) are nondiagnostic. (Choice D) Laparotomy and cesarean delivery are performed in patients with possible abruptio placentae or uterine rupture (ie, uterine tenderness, fetal distress). This patient has a nontender uterus and a reassuring fetal heart rate tracing (eg, moderate variability, accelerations). Educational objective: Nephrolithiasis typically presents with flank pain that radiates to the groin and hematuria. Ultrasound of the kidneys and ureters is used for diagnosis during pregnancy because of this modality's low risk of fetal radiation exposure. References: The role of imaging in the diagnosis and management of renal stone disease in pregnancy. (http://www.ncbi.nlm.nih.gov/pubmed/26454345) ACR appropriateness criteria for acute onset of flank pain with suspicion of stone disease. (http://www.ncbi.nlm.nih.gov/pubmed/27929205) Radiology of renal stone disease. (http://www.ncbi.nlm.nih.gov/pubmed/27816704)

A 28-Year-Old Woman, Gravida 1 Para 0, at 34 Weeks