A male infant, the first child of a non-consanguineous parents, presented at age 4 months with salt depletion and dehydration (plasma sodium (Na) 114, potassium 5.1 mmol/l). He quickly responded to I.V. Saline. During hyponatremia his plasma renin activity (7625 ng AlC?1 hr?1, NR 472-3130) and plasma aldosterone (PAldo) (3670 pmol/l NR 100-500) levels were appropriately elevated and his renal Na reabsorption was normal (fractional tubular excretion 0.2%, N < 1.0%). A normal Na intake of 3 mmol/kg/day led to a further fall in plasma Na (124 mmol/l), an increase PAldo (16,700 pmol/1) and a fall in urinary Na exception. A search for the source of Na loss revealed sweat Na in the upper normal range (53,58 mmol/1), normal rectal potential difference (60 mV) indicating normal intestinal & Na transport, and a markedly elevated salivary Na (170, 151 mmol/l, NR 4-10). Fludrocortisone 0.1 mg. daily induced no fall in salivary Na. On an intake of Na 6 mmol/kg/day, normal plasma Na levels were maintained and he thrived. His parents' salivary Na levels were ^ 15 mmol/l. We suggest that salt depletion was caused by salivary Na loss due to selective end-organ insensitivity to circulating aldosterone.
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机译：一名男婴，是非近亲父母的第一胎，在4个月大时出现了盐耗竭和脱水（血浆钠（Na）114，钾5.1 mmol / l）。他迅速回应了I.V.盐水。在低钠血症期间，他的血浆肾素活性（7625 ng AlC？1 hr？1，NR 472-3130）和血浆醛固酮（PAldo）（3670 pmol / l NR 100-500）水平适当升高，并且肾脏对Na的重吸收正常（分数肾小管排泄物0.2％，N <1.0％。正常的钠摄入量为3 mmol / kg /天会导致血浆Na（124 mmol / l）进一步下降，PADdo升高（16,700 pmol / 1），尿中Na异常下降。对钠损失源的搜索显示，汗液Na处于正常范围的上限（53,58 mmol / 1），正常直肠电位差（60 mV）表明肠道和Na转运正常，唾液Na明显升高（170，151） mmol / l，NR 4-10）。氟可的松0.1毫克。每天诱导唾液钠没有下降。 Na摄入量为6 mmol / kg / day时，血浆Na水平保持正常，并且he壮成长。他父母的唾液Na水平为^ 15 mmol / l。我们认为，盐的消耗是由于唾液中Na丢失所致，这是由于对循环醛固酮的选择性终末器官不敏感性所致。
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