Acute hyponatremia after a religious fast

Abstract Objectives Vigorous exercise or fasting, particularly when followed by excessive fluid intake can lead to dangerous electrolyte abnormalities. Our objective is to describe that polydipsia and intake of nonsteroidal anti-inflammatory drugs (NSAIDs)after fasting while breastfeeding may result in acute symptomatic hyponatremia. Case report We present the case of a 24 year-old woman 4 weeks postpartum who engaged in a 20 hour fast from both eating and drinking, during which she continued to breastfeed her newborn child. After ending her fast, she noted decreased milk supply. Attributing her decreased milk supply to dehydration, she then consumed 4 liters of water with little salt and also took NSAIDs for a headache, which continued to worsen. Upon presentation to the emergency department, she was found to have a sodium level of 124 meq/L (normal range 135-145 meq/L) and a urine specific gravity of 1.015 (normal range 1.005 – 1.030). Thyroid function tests and cortisol level were normal. She was diagnosed with acute, symptomatic hypovolemic hyponatremia. After 1 liter of normal saline her sodium rapidly corrected to normal and her symptoms resolved. At two months follow up she was asymptomatic and had no further episodes of hyponatremia. Discussion Due to the patient’s gender and small body size, 4 liters of water was sufficient to lower her serum sodium rapidly from normal to 124 meq/L. She was unable to excrete this water due to a combination of hypovolemia-mediated AVP and NSAID use. Conclusion Clinicians should be cognizant that reproductive age women are uniquely susceptible to hyponatremia and dangerous sequelae therein. They should counsel fasting individuals, particularly lactating women, to consume solute as well as fluid after fasting.