Acute Hyponatremia After a Religious Fast.

Area of Science:

• Endocrinology
• Nephrology
• Reproductive Medicine

Background:

• Acute symptomatic hyponatremia is a potentially dangerous condition characterized by low serum sodium levels.
• Reproductive-age women, particularly those who are breastfeeding, may be uniquely susceptible to developing hyponatremia.
• Factors such as fasting, excessive fluid intake (polydipsia), and certain medications can precipitate hyponatremia.

Observation:

• A 24-year-old woman, 4 weeks postpartum, fasted for 20 hours while breastfeeding.
• Post-fasting, she consumed 4 L of water with minimal salt and took nonsteroidal anti-inflammatory drugs (NSAIDs) for a headache.
• She presented with worsening symptoms and was found to have a serum sodium level of 124 mEq/L.

Findings:

• The patient was diagnosed with acute symptomatic hypovolemic hyponatremia.
• Her hyponatremia was attributed to excessive water intake, hypovolemia-mediated arginine vasopressin release, and NSAID use, which impaired water excretion.
• Treatment with 1 L of normal saline rapidly corrected her sodium levels and resolved symptoms.

Implications:

• Clinicians must recognize the increased risk of hyponatremia in reproductive-age women, especially lactating individuals.
• Counseling on appropriate fluid and solute intake after fasting is crucial for this population.
• This case underscores the importance of considering polydipsia and NSAID use as contributing factors to hyponatremia.