Hyponatremia: evaluation and management.

BACKGROUND: Hyponatremia is one of the most common electrolyte disorders encountered in clinical practice. The pathophysiology is complex, but its understanding is vital to the disorder's evaluation and treatment. The clinical manifestations of hyponatremia include headache, dizziness, nausea/vomiting, seizures, obtundation, and death. Undercorrection must be avoided, but overly aggressive treatment can also be detrimental.

OBJECTIVES: We review normal water physiology, including central osmosensory mechanisms, that are now becoming better understood. We will then review the classification and causes of hyponatremia and the clinical evaluation and workup of the disorder. Treatment options will be briefly reviewed.

DISCUSSION: Evaluation of hyponatremia begins with a detailed history and physical examination. Appropriate urine and serum studies can contribute to the evaluation and classification of the disorder. Treatment decisions are based on the underlying cause and severity of symptoms.

CONCLUSION: We present an extensive review of the physiology, pathophysiology, clinical evaluation, and management ofhyponatremia.