Hyponatraemia associated with cardiac tamponade and chronic fluid excess

Abstract

SummaryWe describe a complex case of hyponatraemia with two aetiologies. A 49-year-old man who drank 6 litres of dilute alcohol per day presented confused and oedematous with a serum sodium of 95 mmol/litre. Urine sodium was <10 mmol/litre and urine osmolality 440 mOsmol/kg. Chest x-ray demonstrated a globular heart. ECG showed saddle-shaped ST elevation. ECHO demonstrated a large pericardial effusion causing marked tamponade. Following pericardiocentesis there was a marked diuresis; serum sodium returned to normal after 2 weeks. A full recovery ensued. Cardiac tamponade is associated with antidiuresis via release of antidiuretic hormone (ADH). Tamponade is also associated with antinatriuresis. Antidiuresis and antinatriuresis usually balance in cardiac tamponade; excessive fluid intake may have caused an imbalance in this case. BACKGROUND

Pericardial Effusion-Associated Hyponatremia

“…Pericardial effusion-associated hyponatremia has been described in previous case reports [2][3][4][5][6] and retrospective studies [7,8]. In most patients, hyponatremia resolves following medical management or pericardiocentesis.…”

“…Resolution of hyponatremia following pericardiocentesis has been described in case reports by other authors [2][3][4][5][6]. In addition, in a recent review of 31 patients, Jong et al found that individuals with cardiac tamponade-related hyponatremia demonstrated a statistically significant increase in serum sodium levels within 48 hours of pericardiocentesis [7].…”

“…The documented etiologies of pericardial effusion-associated hyponatremia include uremia [ 2 ], malignancy [ 5 , 8 ], medication [ 6 ], and idiopathic [ 3 , 4 ]. In each of these cases, patients had symptomatic cardiac tamponade with hemodynamic instability.…”

“…Pericardial effusion has been identified as a rare cause of hyponatremia. Interestingly, pericardiocentesis often results in rapid and complete reversal of hyponatremia [2][3][4][5][6][7][8][9]. The mechanism underlying pericardial effusionrelated hyponatremia remains to be established.…”