Sodium and Its Multiorgan Targets

Case Presentation: A 66-year-old retired man presented to his physician with complaints of shortness of breath and weight gain over 1 week's time during a recent cruise. He was not short of breath in the supine position, although his neck veins were distended. The blood pressure was 196/104 mm Hg; his heart rate was 92 bpm; and his cardiac rhythm was normal. He had a large habitus and was 76 in tall and 248 lb, which was 27 lb heavier than when he was evaluated 6 weeks previously in the office. The lungs revealed fine crackling rales bilaterally and posteriorly, but no wheezes or other sounds were noted. A fourth heart sound was heard at the apex. The ECG revealed left atrial abnormality and left ventricular hypertrophy with a normal sinus rate and rhythm. The echocardiogram confirmed left ventricular hypertrophy, increased left atrial size, and evidence of impaired diastolic function, and the left ventricular ejection fraction was 32%. Pulse wave velocity and aortic distensibility were impaired. There was severe 4+ bilateral edema of both lower extremities to the knees. Although the hemogram was normal, his blood urea nitrogen and creatinine concentrations were 28 and 1.2 mg/dL, respectively. The urinalysis revealed 4+ proteinuria, and a 24-hour urine collection for sodium content (at the time when his appointment was made) was >13 g.The patient had been a long-time patient of ours, with well-controlled hypertension (receiving an angiotensin II receptor blocker, a calcium antagonist, a β-adrenergic receptor blocker, furosemide, spironolactone, and a statin). He controlled his diet at home, but always was tempted by the cuisine on his frequent vacation cruises. His dietary indiscretion actually produced his 27-lb weight gain within the first 3 days of his cruise and was lost 2 days after his office visit after a temporary increase in …