Severe hyponatremia in preeclampsia: a case report and review of the literature

Purpose To summarize the clinical characteristics and treatments of preeclampsia complicated with hyponatremia. Methods We reported a new case of preeclampsia complicated with severe hyponatremia; searched for relevant articles from the PubMed, Scopus and Cochrane databases; and reviewed all reported cases. Results Twenty-one reported cases were found. Our case is 22nd, and the serum sodium level in this case was the lowest reported. After treatment comprising fluid restriction, hypertonic saline and caesarean section, a relatively good outcome was achieved. In all reported cases, SIADH, preeclampsia or the combined effect of preeclampsia and induced nephrotic syndrome were the speculated pathogeny. Termination was performed due to adverse manifestations; six cases underwent transvaginal deliveries, and sixteen cases underwent caesarean section. Fifteen patients recovered from hyponatremia within 72 h after delivery. Conclusion The pathogenesis of hyponatremia occurring in patients with preeclampsia is still unclear. Termination of the pregnancy led to a stabilization of the sodium level, ICU monitoring was necessary, and fluid restriction and hypertonic saline intake were applied; however, there was no evidence of the effectiveness of the treatments.