Preeclampsia Work Up

Andrew Lane, MD
PGY 4, Greenville Health System
Mentor: Lauren Demosthenes, MD

Clinical Scenario A

A 17 year old G1 @ 35 weeks presented to L+D triage for evaluation of labor. She was determined not to be in labor by the on call physician. However, during her evaluation she was found to have several blood pressures between 140-160/90-110 over a 4 hour observation period. Labs to assess for preeclampsia included Hgb 11.2, platelets 225,000/microliter, creatinine 0.5 mg/dL, AST 17 IU/L, AST 26 IU/L, LDH 173 IU/L and serum uric acid 3.5 mg/dL.

She was admitted to collect a 24 hour urine protein, requiring a 2 night stay. She missed 2 days of school. Her 24 hour urine protein resulted as 294 mg/24 hr. She underwent a detailed growth scan and biophysical profile by Maternal-Fetal medicine. She was discharged with a diagnosis of gestational hypertension.

Clinical Scenario B 

A 17 year old G1 @ 35 weeks presented to L+D triage for evaluation of labor. She was determined not to be in labor by the on call physician, however, during her evaluation she was found to have several blood pressures between 140-160/90-110 over a 4hr observation period. Labs to assess for preeclampsia included Hgb 11.2, Platelets 225,000/microliter, creatinine 0.5 mg/dL, AST 17 IU/L, AST 26 IU/L and an LDH 173 IU/dL. A spot urine protein:creatinine ratio was sent and resulted at 0.23 mg/dL.

She was discharged after 4 hours with a diagnosis of gestational hypertension.

Discussion Questions

• Discuss the utility of the uric acid in diagnosis of preeclampsia.
• Discuss how the p:c ratio may be used in the diagnosis of preeclampsia.
• What are indications to admit a patient to rule in or rule out preeclampsia?

Costs Scenario A

Triage Charges:
Level IV Evaluation Baseline Charge: $1,420.00
Complete Blood Cell Count: $74.80
Complete Metabolic Panel: $199.00
Lactate Dehydrogenase: $70.00
Serum Uric Acid: $41.40
Spot Urine Protein:Creatinine: $48.50

Inpatient Charges:
23hr Observation Baseline Charge: $1,275.13
24hr Urine for Protein: $34.50
Ultrasound by Maternal-Fetal Medicine: $764.10
Other: $1,674.29

Total Charges: $5,601.72

Costs Scenario B

Triage Charges:
Level IV Evaluation Baseline Charge: $1,420.00
Complete Blood Cell Count: $74.80
Complete Metabolic Panel: $199.00
Lactate Dehydrogenase: $70.00
Spot Urine Protein:Creatinine: $48.50

Total Charges: $1,812.30

Teaching Moment 

Serum uric acid (SUA) is a marker of oxidative stress, tissue injury, and renal dysfunction. Its availability and low cost, makes it a potentially useful biomarker for the prediction of preeclampsia and its complications. There have been several reviews on the use of SUA to predict risk of developing preeclampsia when used as a biomarker in early pregnancy, with conflicting results (1). Another potential role of SUA is the prediction of adverse maternal and fetal outcomes in women already diagnosed with preeclampsia. Studies on this are highly conflicted (2-3). ACOG does not recommend using SUA for either of these purposes. However, ACOG does recommend a baseline SUA in pregnancies with chronic hypertension to assist in ruling out causes of potentially treatable secondary hypertension and to assess for end organ damage (4).

ACOG currently recommends diagnosing preeclampsia with either a 24 hour value or a P:C in a single voided urine (4). A ratio > 0.3 mg/dL has been shown to meet or exceed 300 mg protein on a 24 hr urine (5).

This patient underwent both unnecessary testing and unnecessary hospitalization for a diagnosis that could have been made in the triage unit. SUA is not necessary or recommended for the diagnosis of preeclampsia. A P:C ratio is sufficient to assess for proteinuria in the diagnosis of preeclampsia The combination of mild range blood pressures 4 hours apart and a negative laboratory workup, made the diagnosis of gestational hypertension while ruling out the preeclampsia in the triage unit.

References

1. Cnossen JS, de Ruyter-Hanhijarvi H, van der Post JA, Mol BW, Khan KS, ter Riet G. Accuracy of serum uric acid determination in predicting pre-eclampsia: a systematic review. Acta obstetricia et gynecologica Scandinavica. 2006;85(5):519-525.
2. Thangaratinam S, Ismail KM, Sharp S, Coomarasamy A, Khan KS, Tests in Prediction of Pre-eclampsia Severity review g. Accuracy of serum uric acid in predicting complications of pre-eclampsia: a systematic review. BJOG : an international journal of obstetrics and gynaecology. Apr 2006;113(4):369-378.
3. Koopmans CM, van Pampus MG, Groen H, Aarnoudse JG, van den Berg PP, Mol BW. Accuracy of serum uric acid as a predictive test for maternal complications in pre-eclampsia: bivariate meta-analysis and decision analysis. European journal of obstetrics, gynecology, and reproductive biology. Sep 2009;146(1):8-14.
4. American College of O, Gynecologists, Task Force on Hypertension in P. Hypertension in pregnancy. Report of the American College of Obstetricians and Gynecologists' Task Force on Hypertension in Pregnancy. Obstetrics and gynecology. Nov 2013;122(5):1122-1131.
5. Wheeler TL, 2nd, Blackhurst DW, Dellinger EH, Ramsey PS. Usage of spot urine protein to creatinine ratios in the evaluation of preeclampsia. American journal of obstetrics and gynecology. May 2007;196(5):465 e461-464.