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A B S T R A C T In a 19 yr old male with familial hyperkalemic periodic paralysis, paralysis was consistently induced by the administration of potassium chloride, corticotropin-gel, and a variety of glucocorticoids (dexamethasone, 6-methylprednisolone, triamcinolone) but not by mineralocorticoids (D-aldosterone, deoxycorticosterone) or by adrenocorticotropin (ACTH)-gel plus metyrapone. Induced attacks were virtually identical with spontaneous attacks, being associated, after a latent period of a few hours, with a rise in plasma K+ and HCO3-and a simultaneous fall in plasma Na' and Cl-concentrations to an extent implying exchange of 1 K+ with 2 Na+ and 2 Cl-between extracellular and intracellular fluid. ACTH-induced paralysis was preceded by rising serum inorganic P, and associated with increased plasma glucose, blood lactate, and serum creatine phosphokinase concentrations. In normal subjects ACTH, cortisol, and triamcinolone administration failed to change plasma electrolytes or strength, while ingestion of KCI produced no weakness and smaller changes in plasma K and Na than in the patient.Since the patient and normal subjects showed the same changes in renal excretion of K after the administration of cortisol and KCl, it seems likely that paralysis in the patient resulted from abnormally slow uptake (and/or excessive loss) of K by the muscle cells, possibly caused by an abnormal "ion-exchange pump." Normal adrenocortical function and absence of a peak in plasma 11-hydroxycorticoid (11-OHCS) concentration preceding spontaneous paralysis, indicated that spontaneous paralysis did not result from changes in cortisol secretion. Similar hyperkalemic paralysis was precipitated by ACTH-gel in a brother and first cousin of the Dr. Fellerman is a U. S. Public Health Service Trainee in Endocrinology.

1. On constant high (200 mmol)- and low (10 mmol)-sodium diets, thirty-one patients with idiopathic oedema have been compared with six non-oedematous control subjects while upright from 08.00 to 20.00 hours for 3 days and while recumbent all day for 2 days. 2. The cumulative weight rise in the upright posture and fall in recumbency were ‘normal’ in five patients (‘non-orthostatic oedema’) and excessive in twenty-six (‘orthostatic oedema’). 3. Leg volume showed a cumulative rise during the upright period, which was excessive in the orthostatic oedema patients only. 4. When the orthostatic oedema patients were in the upright posture, fifteen retained sodium excessively (‘orthostatic sodium retainers’), while eleven retained ‘normal’ amounts of sodium (‘orthostatic water retainers’). 5. The ‘orthostatic sodium retainers’ experienced excessive acute orthostatic falls in inulin and para-aminohippurate (PAH) clearances. Half of them showed excessive aldosterone excretion and secretion rates and excessive potassium excretion in the upright posture on the 200 mmol of sodium diet. Plamsa volume fell excessively after 1 h in the upright posture in these patients. None of these changes was significant or consistent in the other patients with oedema. 6. Plasma renin activity and plasma protein and albumin concentrations were ‘normal’ in all patients in all circumstances. 7. Idiopathic oedema is a group of disorders each associated with: (I) orthostatic fall in filtered sodium often with orthostatic hyperaldosteronism and consequent orthostatic sodium retention; (II) orthostatic water retention possibly related to orthostatic hypervasopressinism and occasionally associated with occult heart failure; or (III) non-orthostatic factors.

Myotonic dystrophy (MyD) is a common genetic neuromuscular disorder in which chromosome 19 gives rise to an abnormal expansion of CTG-trinucleotide repeats. MyD is a highly variable multisystem disorder with muscular and nonmuscular abnormalities. Increasingly, endocrine abnormalities, such as gonadal, pancreatic, and adrenal dysfunction are being uncovered. Herein we present three unrelated cases with MyD with abnormally elevated serum potassium; 2 of the 3 cases presented clinically with cardiac dysrhythmias. Hyperkalaemic conditions such as renal failure, cortisol deficiency, pseudohyperkalaemia, and hyperkalaemic periodic paralysis were excluded. Further endocrine evaluation revealed baseline hypoaldosteronism associated with elevated renin activity. Perturbation of the renin-angiotensin-aldosterone system resulted in appropriately enhanced renin activity but with a subnormal aldosterone response, which appeared to be due to adrenal hyporesponsiveness. The treatment of all cases with fludrocortisone was without effect. Whether the apparent mineralocorticoid abnormality in MyD is due to associated hormonal perturbations (i.e. excessive ACTH responsiveness. elevated cytokines, elevated atrial natriuretic hormone, etc.), adrenal atrophy, and/or a manifestation of the underlying kinase dysfunction is uncertain, but merits further evaluation in view of the clinical consequence of hyperkalaemia.