Studies on the characteristics of the control system governing sodium excretion in uremic man.

Sodium excretion was studied in a group of patients with chronic renal disease, (a) on constant salt intakes of varying amounts with and without mineralocorticoid hormone administration and, (b) after acute extracellular fluid volume expansion. The lower the steady-state glomerular filtration rate (GFR), the greater was the fraction of filtered sodium excreted on both a 3.5 and 7.0 g salt diet; and the lower the GFR, the greater was the change in fractional excretion in the transition from the 3.5 to the 7.0 g salt diet. This regulatory capacity did not appear to be influenced by mineralocorticoid hormone administration. After acute expansion of extracellular fluid (ECF) volume, the increment in sodium excretion exceeded the concomitant increment in filtered sodium in six of nine studies and in the remaining three studies, the increment in excretion averaged 59% of the Delta filtered load (i.e., only 41% of the increase in filtered sodium was reabsorbed). During saline loading, the decrease in fractional reabsorption of sodium tended to vary inversely with the steady-state GFR, although all patients received approximately the same loading volume. When an edema-forming stimulus was applied during saline infusion, the natriuretic response was aborted and the lag time was relatively short. When GFR and the filtered load of sodium were increased without volume expansion, the Delta sodium excretion averaged only 19% of the Delta filtered load; moreover, changes in fractional sodium reabsorption were considerably smaller than those observed during saline loading. The data implicate the presence of a factor other than GFR and mineralocorticoid changes in the modulation of sodium excretion in uremic man.

Control of phosphate excretion in uremic man.

The present studies were performed in an effort to examine the characteristics of the control system governing phosphate excretion in uremic man. In a group of patients with glomerular filtration rates (GFR) ranging from normal to 2 ml/min, it was found that the lower the GFR the lower the fraction of filtered phosphate reabsorbed (TRP). On a fixed phosphate intake, phosphate excretion rate was the same in patients with GFRs ranging from 60 to 3 ml/min. When plasma phosphate concentrations were diminished to subnormal levels in hyperphosphatemic, hypocalcemic uremic patients, TRP values increased but did not return to normal. TRP failed to rise substantially when GFR, as well as plasma phosphate concentrations, were diminished. In patients with unilateral renal disease, TRP values were equal bilaterally, and values were substantially higher in the diseased kidneys than in patients with bilateral involvement. When plasma calcium concentrations were raised to normal for 2-3 wk in uremic patients in whom plasma phosphate concentrations had previously been lowered to subnormal levels, TRP values rose to an average value of 86%. Values remained in the normal range when phosphate concentrations were allowed to increase while normocalcemia was maintained. The data are interpreted to indicate that in advancing renal disease, the changing patterns of phosphate excretion are mediated by a control system in which parathyroid hormone serves as a major effector element. An increase in GFR per nephron, hyperphosphatemia, and intrinsic inability of the surviving nephrons to transport phosphate do not appear to be of primary importance in the progressive reduction in TRP.

Transient hepatocellular injury during attacks of cholinergic urticaria.

Cholinergic urticaria presents as wheals and erythroderma that develop in response to a variety of factors which stimulate muscarinic receptors, including exercise, heat, cold, sweat and emotional stress. We describe a 25-year-old man with ulcerative colitis who developed cholinergic urticaria diagnosed by a metacholine test. He had had seven previous attacks over 8 years, and the finding of elevated liver enzymes required admission to four different hospitals. The clinical picture was identical: urticaria, hepatosplenomegaly, lymphadenopathy and elevation of liver enzymes. The causative agent was never identified and recovery was complete, with or without antibiotic therapy. To the best of our knowledge, this is the first description of liver involvement in cholinergic urticaria noted in the English-language medical literature.

Methysergide therapy causing vascular insufficiency of the upper limb.

A 41-year-old woman, who was receiving methysergide maleate for the treatment of severe headaches, had occlusion of the left brachial artery, confirmed by arteriography. The occlusion was believed to result from the use of methysergide and the drug was therefore withdrawn. Within 4 days the distal pulses were normal, as confirmed by arteriography, and she was asymptomatic.

Hyperviscosity syndrome in rheumatoid arthritis.

The course of a patient with rheumatoid hyperviscosity syndrome is described. Manifestations of hyperviscosity included somnolence, circulatory overload, bleeding diathesis and dilated retinal veins. Serum hyperviscosity was associated with marked hypergammaglobulinemia, elevated IgM and IgG serum concentrations, and high titers of rheumatoid factor. High molecular weight IgG-IgM immune complexes shown in the serum were considered responsible for the increased viscosity. An unusual feature of the hyperviscosity, was spurious hyponatremia and a negative anion gap. Plasmapheresis rapidly controlled acute features of hyperviscosity, lowered gamma globulin concentrations and led to normal serum sodium and anion gap. Clinical improvement was maintained with moderate prednisone doses.