Hypernatraemia and Hyponatraemia 47 



volume was greater than normal. The infant did not excrete a 

 dose of water at the normal rate and the authors thought she 

 was secreting an excess of ADH. An excessive secretion of 

 ADH would, of course, be appropriate only to a restricted 

 fluid intake. When her fluid intake was restricted the plasma 

 [Na] rose to normal. 



Schwartz and co-workers (1957) have recently suggested 

 that an inappropriate secretion of ADH might account for 

 the hyponatraemia in two patients with carcinoma of the 

 bronchus whom they studied. They imply that there was an 

 abnormal stimulation of the receptors for maintaining the 

 volume of the body fluids. Their patients had normal renal 

 and adrenal function; they excreted a normal amount of 

 aldosterone. In one of them the plasma [Na] fell as low as 

 103 m-equiv./l., but the extracellular volume, far from being 

 reduced as in sodium deficiency, was expanded and there 

 was no evidence of peripheral vascular failure. The urine 

 was generally hypertonic to the plasma, and this is the 

 principal argument adduced by Schwartz and co-workers 

 that these patients were producing too much ADH. The 

 kidneys of these patients did not conserve sodium when their 

 fluid intake was unrestricted, though they did so when 

 large amounts of salt-retaining steroids were given. Schwartz 

 and co-workers do not comment on the rate of excretion of a 

 dose of water. But there is no doubt the kidneys did respond 

 normally to water deprivation. Under this stimulus the 

 urinary sodium fell and the plasma [Na] rose. Others have 

 also described this response to water deprivation in hypo- 

 natraemia (see Edelman, 1956). It might be interpreted as 

 the usual "dehydration reaction". 



Some observations we have made on two patients with 

 unexplained hyponatraemia are relevant. 



Case reports 



Albert, aged 62, was admitted on 25th May 1957 in status epilepticus 

 accompanied by hyperpjTcxia and heavy sweating. He had been up 

 and about until then, although he had had a right hemiparesis for two 

 years, which had become worse two months before admission. His 



