Which symptom would indicate a diagnosis of preeclampsia with severe features?

A doubling of serum creatinine concentration is a critical indicator of preeclampsia with severe features. Preeclampsia is characterized by the development of hypertension and often involves signs of kidney dysfunction. An increase in serum creatinine emphasizes acute kidney injury, which is a key parameter used in evaluating the severity of preeclampsia. The elevation in creatinine levels suggests that the kidneys are not filtering waste products effectively, which can lead to significant maternal and fetal complications if not managed promptly.

Other symptoms, while concerning, do not distinctly define preeclampsia with severe features in the same way. For instance, severe headache without visual changes is a common presentation in preeclampsia but is not specific to severe features on its own. Similarly, persistent swelling of lower extremities can occur in normal pregnancy or mild cases and does not correlate as closely with the severe manifestations. A sudden drop in blood pressure is also not typical in preeclampsia, where hypertension is a defining characteristic. Thus, the doubling of serum creatinine is a stronger diagnostic criterion for recognizing the severity of preeclampsia.